WO2025134987A1 - Vinyl-based polymer, production method therefor, and curable resin composition - Google Patents

Abstract

Provided is a vinyl-based polymer having a crosslinkable functional group. A cured object of the vinyl-based polymer has a recovery of 75% or greater and an elongation at break of 300-600%.

Description

Vinyl polymer, its production method, and curable resin composition

CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Japanese Patent Application No. 2023-217244, filed on December 22, 2023, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a vinyl polymer, a method for producing the same, and a curable resin composition.

　Vinyl polymers with crosslinkable functional groups are widely known as curable resins used in industrial applications. Vinyl polymers with crosslinkable groups are blended with other components as necessary, and are widely used as curable resin compositions to produce a variety of cured products, such as paints, adhesives, pressure sensitive adhesives, sealants, molding materials, rubber sheets, etc.

Patent Document 1 discloses a vinyl polymer having crosslinkable silyl groups at both ends, obtained by living radical polymerization, as a vinyl polymer to be blended into a curable resin composition for producing a cured product.

Japanese Patent Application Publication No. 11-130931

In recent years, with the improvement in the durability of buildings themselves, there is a high demand for sealants with high tensile properties, heat resistance, and weather resistance in sealants used in buildings. In particular, in applications where outdoor use is expected, such as construction applications, it is desirable for the cured product (particularly the surface) obtained by curing the curable resin composition to have weather resistance (hereinafter also referred to as "dynamic weather resistance") that can withstand dynamic deformation of the cured product itself due to temperature, humidity, etc.

The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a vinyl polymer that can give a cured product that has excellent tensile properties, heat resistance, and weather resistance.

As a result of intensive research conducted by the present inventors to solve the above problems, it has been discovered that a vinyl polymer having a crosslinkable functional group, in which the physical properties of the cured product of the vinyl polymer are within a specific range, can provide a cured product having excellent tensile properties, heat resistance, and weather resistance (particularly dynamic weather resistance). Specifically, the present disclosure provides the following vinyl polymer, a method for producing the same, and a curable resin composition.

[1] A vinyl polymer having a crosslinkable functional group, the vinyl polymer having a recovery rate of 75% or more when cured and a breaking elongation of 300 to 600%.
[2] The vinyl polymer according to [1], wherein the average number of the crosslinkable functional groups per molecule is 1.8 or more.
[3] The vinyl polymer according to [1] or [2], which contains 0.1 to 50 mass% of structural units derived from an alkyl (meth)acrylate having an alkyl group having 10 or more carbon atoms in the ester moiety, based on all structural units constituting the vinyl polymer.
[4] The vinyl polymer according to any one of [1] to [3], wherein a ratio of structural units derived from an alkyl (meth)acrylate ester having an alkyl group having 2 or less carbon atoms in an ester moiety is 20 mass % or less based on all structural units constituting the vinyl polymer.
[5] The vinyl polymer according to [1] or [2], which contains structural units derived from an alkyl (meth)acrylate having an alkyl group with 10 or more carbon atoms in the ester moiety in an amount of 0.1 to 50 mass% based on all structural units constituting the vinyl polymer, and the proportion of structural units derived from an alkyl (meth)acrylate having an alkyl group with 2 or less carbon atoms in the ester moiety is 20 mass% or less based on all structural units constituting the vinyl polymer.
[6] The vinyl polymer according to any one of [1] to [5], which is a block copolymer consisting of polymer block (A)/polymer block (B)/polymer block (A).
[7] The vinyl polymer according to [6], wherein the polymer block (A) has the crosslinkable functional group.
[8] The vinyl polymer according to any one of [1] to [7], having a weight average molecular weight (Mw) of 30,000 to 100,000 and a molecular weight distribution (Mw/Mn) of 1.80 or less.
[9] A curable resin composition comprising the vinyl polymer according to any one of [1] to [8] and an oxyalkylene polymer having a crosslinkable silyl group.
[10] The curable resin composition according to [9], wherein a mass ratio of the vinyl polymer to the oxyalkylene polymer is 10/90 to 90/10, when expressed as vinyl polymer/oxyalkylene polymer.
[11] The curable resin composition according to [9] or [10], which is for use as a sealant, an adhesive, a pressure-sensitive adhesive, or a coating material.

[12] The method for producing a vinyl polymer according to any one of [1] to [8], comprising a polymerization step of polymerizing a vinyl monomer, the vinyl monomer comprising a vinyl monomer having a crosslinkable functional group, and the polymerization step comprises carrying out polymerization while continuously or intermittently supplying into a reactor at least a part of the total amount of the vinyl monomer having a crosslinkable functional group used in the production of the vinyl polymer.
[13] The method for producing a vinyl polymer according to [12], wherein the vinyl polymer is produced by living radical polymerization.

[14] A method for producing a vinyl polymer having a crosslinkable functional group, the vinyl polymer being a block copolymer consisting of polymer block (A)/polymer block (B)/polymer block (A), the average number of the crosslinkable functional groups per molecule being 1.8 or more, the method comprising: a first polymerization step of polymerizing a vinyl monomer in the presence of a living radical polymerization controller and a polymerization initiator to obtain the polymer block (A); and a second polymerization step of polymerizing a vinyl monomer in the presence of the polymer block (A) obtained in the first polymerization step and a polymerization initiator to form the polymer block (B), the vinyl monomer used in the first polymerization step comprising a vinyl monomer having a crosslinkable functional group, the first polymerization step comprising carrying out polymerization while continuously or intermittently supplying into a reactor at least a part of the total amount of the vinyl monomer having a crosslinkable functional group used to produce the polymer block (A).
[15] The method for producing a vinyl polymer according to [14], wherein the living radical polymerization inhibitor is a chain exchange transfer mechanism type polymerization inhibitor.
[16] The method for producing a vinyl polymer according to [14] or [15], wherein the ratio of the vinyl monomer having a crosslinkable functional group to be continuously or intermittently fed into a reactor is 10 to 100 mass % based on the total amount of the vinyl monomer having a crosslinkable functional group used in the production of the polymer block (A).

The vinyl polymer disclosed herein can produce a cured product that exhibits excellent tensile properties, heat resistance, and weather resistance (especially dynamic weather resistance).

The present disclosure will be described in detail below. In this specification, "(meth)acrylic" means acrylic and/or methacrylic. "(meth)acrylate" means acrylate and/or methacrylate. "(meth)acryloyl" means acryloyl and/or methacryloyl.

<Vinyl polymer>
The vinyl polymer of the present disclosure (hereinafter also simply referred to as "vinyl polymer") is a polymer having a crosslinkable functional group, a recovery rate of a cured product of the polymer being 75% or more, and a breaking elongation being 300 to 600%.

(Crosslinkable functional group)
Examples of the crosslinkable functional group possessed by the vinyl polymer include a crosslinkable silyl group, a silanol group, a carboxyl group, a hydroxyl group, an epoxy group, an oxazoline group, an isocyanate group, and a polymerizable unsaturated group. Of these, the crosslinkable functional group possessed by the vinyl polymer is preferably a crosslinkable silyl group, in that it can provide a cured product obtained by using the vinyl polymer with superior breaking elongation and breaking strength, and in that it is easy to control the reactivity.

Examples of crosslinkable silyl groups include alkoxysilyl groups and halogenosilyl groups. Specific examples of these include trimethoxysilyl groups, triethoxysilyl groups, triisopropoxysilyl groups, tris(2-propenyloxy)silyl groups, methyldimethoxysilyl groups, diethoxymethylsilyl groups, ethyldiethoxysilyl groups, diisopropoxymethylsilyl groups, (chloromethyl)dimethoxysilyl groups, and (ethoxymethyl)dimethoxysilyl groups. Of these, alkoxysilyl groups are preferred because they exhibit good reactivity while also having high storage stability.

The crosslinkable silyl group as a whole can be regarded as one reaction point. Therefore, in this specification, the entire crosslinkable silyl group is considered to be one crosslinkable functional group. For example, vinyltrimethoxysilane is a vinyl monomer having a trimethoxysilyl group as a crosslinkable functional group, and the number of crosslinkable functional groups in one molecule is one. Also, vinylmethyldimethoxysilane is a vinyl monomer having a methyldimethoxysilyl group as a crosslinkable functional group, and the number of crosslinkable functional groups in one molecule is one.

(Recovery rate)
The vinyl polymer has a recovery rate of 75% or more for the cured product obtained by curing the polymer. Here, the recovery rate of the cured vinyl polymer refers to the ratio of the strain recovered after removing the load to the strain when the cured vinyl polymer is stretched by applying a load to the cured vinyl polymer for a certain period of time. That is, it is possible to apply a load to the cured vinyl polymer for a certain period of time to stretch the cured vinyl polymer, and the recovery behavior of at least a part of the strain of the cured vinyl polymer can be observed after removing the load applied to the cured vinyl polymer, so that the recovery rate of the cured vinyl polymer can be obtained. Specifically, when the gauge length [mm] before stretching is L ₀ , the gauge length [mm] when stretched by applying a load for a certain period of time is L ₁ , and the gauge length [mm] after removing the load is L ₂ , the recovery rate (unit %) of the cured vinyl polymer is expressed by the following formula (1).
Restoration rate [%] = (L ₁ - _{L 2} )/(L ₁ - _{L 0} ) x 100...(1)

The restoration rate expressed by the above formula (1) can be used as an index of the rubber elasticity of a vinyl polymer. In other words, the higher the restoration rate of a cured vinyl polymer, the higher the rubber elasticity of the vinyl polymer can be evaluated. The restoration rate of a cured vinyl polymer can be adjusted to a desired range by controlling the average number of crosslinkable functional groups per vinyl polymer molecule, the type of crosslinkable functional group, and the position at which the crosslinkable functional group is introduced. Details of the method for measuring the restoration rate of a cured product follow the method described in the Examples below.

If the recovery rate of the cured vinyl polymer, expressed by the above formula (1), is less than 75%, the weather resistance of the cured vinyl polymer obtained using the curable resin composition is insufficient. From the viewpoint of obtaining a cured vinyl polymer with good weather resistance (particularly dynamic weather resistance), the recovery rate of the cured vinyl polymer is preferably 76% or more, more preferably 78% or more, and even more preferably 80% or more. If the recovery rate is within the above range, even if the cured vinyl polymer repeatedly expands and contracts due to external changes such as temperature and humidity, the occurrence of cracks and wrinkles in the cured vinyl polymer due to the expansion and contraction can be effectively suppressed. The upper limit of the recovery rate is not particularly limited, and is a value of 100% or less.

(Elongation at break)
The vinyl polymer has a breaking elongation of 300 to 600%. When the breaking elongation of the vinyl polymer is less than 300%, the cured product is inferior in flexibility. For this reason, for example, when the vinyl polymer is applied to a sealant for an exterior wall material, the cured product (sealant) cannot follow the expansion and contraction of the exterior wall material (more specifically, the variation of the joint width) due to vibration, temperature, humidity, etc., and as a result, cracks and wrinkles are likely to occur in the cured product. In addition, when the breaking elongation of the vinyl polymer cured product exceeds 600%, the strength of the cured product is reduced. From the viewpoint of improving the weather resistance (particularly dynamic weather resistance) and strength of the cured product in a well-balanced manner, the breaking elongation of the vinyl polymer cured product is preferably 305% or more, more preferably 310% or more. In addition, the breaking elongation of the vinyl polymer cured product is preferably 550% or less, more preferably 500% or less, and even more preferably 450% or less. The breaking elongation of the cured product is a value measured in accordance with JIS K 6251:2017. The breaking elongation of the cured product of the vinyl polymer can also be adjusted to a desired range by controlling the average number of crosslinkable functional groups per vinyl polymer molecule, the type of crosslinkable functional group, and the introduction position of the crosslinkable functional group. Details of the measurement method are as described in the examples below.

Here, in this specification, the "cured vinyl polymer" which is the object (i.e., test piece) for measuring the recovery rate and breaking elongation is a cured product obtained by using the vinyl polymer alone or by using a composition which contains the vinyl polymer and does not contain any components other than the solvent and curing component (specifically, the crosslinking agent and curing catalyst described below) in order to evaluate the recovery rate and breaking elongation of the vinyl polymer itself. In terms of ease of forming a cured product, a cured product formed by a composition consisting of a vinyl polymer and a curing component or a composition consisting of a vinyl polymer, a solvent, and a curing component can be preferably used as the cured vinyl polymer.

For example, in the case of a vinyl polymer having a crosslinkable silyl group as a crosslinkable functional group, a composition consisting of a vinyl polymer having a crosslinkable silyl group and a curing catalyst, or a cured product formed from a composition consisting of a vinyl polymer having a crosslinkable silyl group, a curing catalyst, and a solvent is used as the test piece. In this case, the amount of curing catalyst can be appropriately set, but can be, for example, 0.3 to 3.0 parts by mass per 100 parts by mass of the vinyl polymer having a crosslinkable silyl group. The details of the procedure for preparing the measurement target for the recovery rate and breaking elongation follow the method described in the examples below.

The vinyl polymer of the present disclosure may have a crosslinkable functional group, a recovery rate of the cured product of 75% or more, and a breaking elongation of 300 to 600%, and the type and structure of the monomers constituting the vinyl polymer are not particularly limited. Preferred aspects of the vinyl polymer of the present disclosure are described in detail below.

(Monomer)
As a monomer constituting a vinyl polymer, a vinyl monomer having a crosslinkable functional group (hereinafter, also referred to as a "crosslinkable group-containing vinyl monomer") is preferably used, since a vinyl polymer having a crosslinkable functional group can be easily obtained.

Specific examples of crosslinkable group-containing vinyl monomers include crosslinkable silyl group-containing vinyl compounds, unsaturated carboxylic acids, unsaturated acid anhydrides, hydroxyl group-containing vinyl compounds, epoxy group-containing vinyl compounds, primary or secondary amino group-containing vinyl compounds, oxazoline group-containing vinyl compounds, and isocyanate group-containing vinyl compounds. The crosslinkable group-containing vinyl monomer may be one of these, or two or more of them.

Examples of crosslinkable silyl group-containing vinyl compounds include vinyl silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilane; trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, methyldimethoxysilylpropyl (meth)acrylate, dimethylmethoxysilylpropyl (meth)acrylate, trimethoxysilylmethyl (meth)acrylate, methyldimethoxysilylmethyl (meth)acrylate, 8-(trimethoxysilyl) (meth)acrylate, ) octyl and other alkoxysilyl group-containing (meth)acrylic acid esters; aromatic vinyl group-containing alkoxysilanes such as p-styryltrimethoxysilane, p-styrylmethyldimethoxysilane, p-styryldimethylmethoxysilane, p-styryltriethoxysilane, p-styrylmethyldiethoxysilane, and p-styryldimethylethoxysilane; alkoxysilyl group-containing vinyl ethers such as trimethoxysilylpropylvinyl ether; and alkoxysilyl group-containing vinyl esters such as vinyl trimethoxysilylundecanoate. Crosslinkable silyl group-containing vinyl compounds are suitable in that they can efficiently carry out the polymerization reaction and subsequent crosslinking reaction when producing a vinyl polymer, since a crosslinked structure is formed by dehydration condensation between crosslinkable silyl groups.

Examples of unsaturated carboxylic acids include (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and further, monoalkyl esters of unsaturated dicarboxylic acids (monoalkyl esters of maleic acid, fumaric acid, itaconic acid, citraconic acid, etc.).
Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, and citraconic anhydride.

Examples of the hydroxy group-containing vinyl compound include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and mono(meth)acrylic acid esters of polyalkylene glycols (e.g., polyethylene glycol, polypropylene glycol, etc.).
Examples of the epoxy group-containing vinyl compound include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate.

Examples of primary or secondary amino group-containing vinyl compounds include amino group-containing (meth)acrylic acid esters such as aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, N-methylaminoethyl (meth)acrylate, and N-ethylaminoethyl (meth)acrylate; and amino group-containing (meth)acrylamides such as aminoethyl (meth)acrylamide, aminopropyl (meth)acrylamide, N-methylaminoethyl (meth)acrylamide, and N-ethylaminoethyl (meth)acrylamide.

Examples of the oxazoline group-containing vinyl compound include 2-isopropenyl-2-oxazoline and 2-vinyl-2-oxazoline.
Examples of the isocyanate group-containing vinyl compound include 2-isocyanatoethyl (meth)acrylate and (meth)acryloyl isocyanate.

Among these, vinyl compounds containing crosslinkable silyl groups are preferred as crosslinkable group-containing vinyl monomers, since they can give cured products that are excellent in breaking elongation and breaking strength, and also exhibit good weather resistance.

The average number of crosslinkable functional groups per molecule of the vinyl polymer is preferably 1.8 or more. When the average number of crosslinkable functional groups in one molecule of the vinyl polymer is 1.8 or more, the recovery rate of the cured product of the vinyl polymer can be increased, and the weather resistance (particularly dynamic weather resistance) of the cured product obtained by using the curable resin composition can be further improved. From this viewpoint, the average number of crosslinkable functional groups in one molecule of the vinyl polymer is more preferably 2.0 or more, even more preferably 2.2 or more, even more preferably 2.4 or more, even more preferably 2.7 or more, and even more preferably 3.0 or more. In addition, in order to make the breaking elongation of the cured product obtained by using the curable resin composition more excellent, the average number of crosslinkable functional groups in one molecule of the vinyl polymer is preferably 8.0 or less, more preferably 7.0 or less, even more preferably 6.0 or less, and even more preferably 5.5 or less.

The preferred range of the average number of crosslinkable functional groups per molecule in the vinyl polymer can be set by appropriately combining the upper and lower limits described above. Specifically, the average number of crosslinkable functional groups per molecule in the vinyl polymer is preferably 1.8 to 8.0, more preferably 2.0 to 7.0, even more preferably 2.2 to 6.0, and even more preferably 2.4 to 5.5.

The average number of crosslinkable functional groups in a vinyl polymer can be calculated by ¹ H-NMR measurement and gel permeation chromatography (GPC) measurement. For example, when determining the average number of crosslinkable functional groups in a vinyl polymer having a crosslinkable silyl group as a crosslinkable functional group, first, the structural units constituting the polymer are identified, and the monomers used in the polymerization are determined. Then, the polymer composition and the molar fraction of the crosslinkable silyl group ^- containing monomer are calculated from the integral value of the signal derived from the hydrogen atom bonded to the carbon atom of the alkoxysilane, which is observed around 3.5 ppm in the 1 H-NMR spectrum, and then the average number of crosslinkable silyl groups in one molecule can be calculated by multiplying this molar fraction by the number average molecular weight (Mn) obtained by GPC measurement.

The vinyl polymer may contain a structural unit derived from a vinyl monomer containing a crosslinkable group (hereinafter also referred to as a "crosslinkable group-containing vinyl unit") and a structural unit derived from a vinyl monomer other than the crosslinkable group-containing vinyl monomer (hereinafter also referred to as an "other vinyl monomer"). The other vinyl monomer is not particularly limited as long as it is a monomer that can be copolymerized with the crosslinkable group-containing vinyl monomer. Specific examples of the other vinyl monomer include (meth)acrylic acid alkyl ester compounds, (meth)acrylic acid aliphatic cyclic ester compounds, (meth)acrylic acid aromatic ester compounds, and the following formula (1):
_CH2 = ^CR1 -C(=O)O-( ^R2O ) _n - ^R3 ...(1)
(In formula (1), ^R1 represents a hydrogen atom or a methyl group, ^R2 represents a linear or branched alkylene group having 2 to 6 carbon atoms, ^R3 represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n represents an integer of 1 to 100.)
Examples of the monomers that constitute the vinyl polymer include compounds represented by the formula (I) below, styrene-based compounds, maleimide compounds, amide group-containing vinyl compounds, and fluorine-containing (meth)acrylic acid ester compounds. The other monomers that constitute the vinyl polymer may be one or more of these.

Specific examples of (meth)acrylic acid alkyl ester compounds include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and icosyl (meth)acrylate.

Specific examples of aliphatic cyclic ester compounds of (meth)acrylic acid include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentanyl (meth)acrylate.

Specific examples of aromatic ester compounds of (meth)acrylic acid include phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxymethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, and 3-phenoxypropyl (meth)acrylate.

Regarding the compound represented by the above formula (1), when n in the above formula (1) is 1, the compound represented by the above formula (1) has an oxyalkylene structure such as an oxyethylene chain, an oxypropylene chain, or an oxybutylene chain. Specific examples of the compound in which n in the above formula (1) is 1 (i.e., an (meth)acrylic acid alkoxyalkyl ester compound) include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, n-propoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, ethoxypropyl (meth)acrylate, n-propoxypropyl (meth)acrylate, n-butoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, n-propoxybutyl (meth)acrylate, and n-butoxybutyl (meth)acrylate.

When n in the above formula (1) is 2 or more, the compound represented by the above formula (1) has a polyoxyalkylene structure such as a polyoxyethylene chain, a polyoxypropylene chain, and a polyoxybutylene chain. When n is 2 or more, two or more ^R2 in the above formula (1) may be the same or different from each other. That is, the compound in which n in the above formula (1) is 2 or more may have different types of polyoxyalkylene structures in one molecule, such as a block structure consisting of polyoxyethylene/polyoxypropylene.

Specific examples of compounds in which n in the above formula (1) is 2 or more include polyoxyethylene (meth)acrylate, polyoxypropylene (meth)acrylate, polyoxybutylene (meth)acrylate, polyoxyethylene-polyoxypropylene (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, lauroxypolyethylene glycol (meth)acrylate, stearoxypolyethylene glycol (meth)acrylate, octoxypolyethylene glycol polypropylene glycol (meth)acrylate, nonylphenoxypolypropylene glycol (meth)acrylate, and phenoxypolyethylene glycol polypropylene glycol (meth)acrylate.

Specific examples of styrene-based compounds include styrene, α-methylstyrene, β-methylstyrene, vinylxylene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, p-n-butylstyrene, p-isobutylstyrene, p-t-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, o-isopropenylphenol, o-vinylbenzoic acid, m-vinylbenzoic acid, p-vinylbenzoic acid, divinylbenzene, and vinylnaphthalene.

Specific examples of maleimide compounds include maleimide and N-substituted maleimide compounds. N-substituted maleimide compounds include N-alkyl-substituted maleimide compounds such as N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, and N-stearylmaleimide; N-cyclopentylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, and N-stearylmaleimide; N-cycloalkyl-substituted maleimide compounds such as N-cyclohexylmaleimide and N-cycloalkyl-substituted maleimide compounds; N-phenylmaleimide, N-(4-hydroxyphenyl)maleimide, N-(4-acetylphenyl)maleimide, N-(4-methoxyphenyl)maleimide, N-(4-ethoxyphenyl)maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, and N-benzylmaleimide and other N-aryl-substituted maleimide compounds.

Specific examples of amide group-containing vinyl compounds include (meth)acrylamide, (meth)acrylamide derivatives, and N-vinylamide monomers. Of these, specific examples of (meth)acrylamide derivatives include tert-butyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and (meth)acryloylmorpholine. Specific examples of N-vinylamide monomers include N-vinylacetamide, N-vinylformamide, and N-vinylisobutylamide.

Specific examples of fluorine-containing (meth)acrylic acid ester compounds include trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, perfluoroethylene, perfluoropropylene, vinylidene fluoride, etc.

Other vinyl monomers include, in addition to those mentioned above, vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate; alkenes such as ethylene and propylene; conjugated dienes such as butadiene and isoprene; vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol.

The other vinyl monomer preferably contains a (meth)acrylic acid alkyl ester compound, because it is easy to obtain a vinyl polymer with a low Tg and excellent fluidity. As the (meth)acrylic acid alkyl ester compound, a (meth)acrylic acid alkyl ester having an alkyl group (R) of 1 to 20 carbon atoms in the ester portion (-COOR) can be preferably used, because it is easy to obtain a vinyl polymer with a low glass transition temperature (Tg) and excellent fluidity. The (meth)acrylic acid alkyl ester compound constituting the vinyl polymer is more preferably a (meth)acrylic acid alkyl ester having an alkyl group of 2 to 20 carbon atoms in the ester portion, even more preferably a (meth)acrylic acid alkyl ester having an alkyl group of 2 to 18 carbon atoms in the ester portion, and even more preferably a (meth)acrylic acid alkyl ester having an alkyl group of 4 to 18 carbon atoms in the ester portion. In addition, the vinyl polymer preferably contains a structural unit derived from an acrylic monomer, and more preferably contains a structural unit derived from an acrylic acid alkyl ester compound, because it can be a polymer with excellent weather resistance and fluidity.

In the vinyl polymer, the proportion of structural units derived from (meth)acrylic acid alkyl ester compounds is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, and even more preferably 90% by mass or more, based on the total structural units constituting the vinyl polymer, from the viewpoint of obtaining a vinyl polymer with excellent fluidity. Note that the (meth)acrylic acid acrylic ester compounds constituting the vinyl polymer may be of only one type, or of two or more types.

When considering the mechanical properties of a vinyl polymer, it is preferable that the vinyl polymer has a structural unit derived from an alkyl (meth)acrylate ester having an alkyl group with 4 to 18 carbon atoms in the ester portion. From the viewpoint of achieving both the fluidity and mechanical properties of the vinyl polymer, in an alkyl (meth)acrylate ester having an alkyl group with 4 to 18 carbon atoms in the ester portion, the number of carbon atoms in the alkyl group in the ester portion is preferably 4 to 16, and more preferably 4 to 15.

In the vinyl polymer, the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 4 to 18 carbon atoms in the ester portion is preferably 25% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on the total structural units constituting the vinyl polymer, from the viewpoint of obtaining a vinyl polymer that exhibits fluidity and has excellent mechanical properties.

In particular, in terms of facilitating the production of a vinyl polymer having a low Tg and excellent fluidity, it is preferable that the vinyl polymer contains a structural unit derived from an alkyl (meth)acrylate ester having an alkyl group with 10 or more carbon atoms in the ester portion. By using a vinyl polymer having a low Tg and excellent fluidity as a component of a curable resin composition, the workability when using the curable resin composition can be improved. In addition, by the vinyl polymer containing a structural unit derived from an alkyl (meth)acrylate ester having an alkyl group with 10 or more carbon atoms in the ester portion, when a polymer different from the vinyl polymer (e.g., a polyoxyalkylene polymer, hereinafter also referred to as "other polymer") is blended into the curable resin composition when preparing a curable resin composition containing the vinyl polymer, compatibility with the other polymer can be improved. This is preferable in that the mechanical properties of the cured product obtained from the curable resin composition can be improved.

When the vinyl polymer contains a structural unit derived from an alkyl (meth)acrylate ester having an alkyl group with 10 or more carbon atoms in the ester portion, it is preferable to use an alkyl (meth)acrylate ester having an alkyl group with 10 to 18 carbon atoms in the ester portion as the alkyl (meth)acrylate ester constituting the structural unit, from the viewpoint of ensuring the fluidity of the vinyl polymer.

In the vinyl polymer, the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 10 or more carbon atoms in the ester portion is preferably 0.1% by mass or more, more preferably 1.0% by mass or more, even more preferably 2% by mass or more, even more preferably 5% by mass or more, even more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total structural units constituting the vinyl polymer. In addition, the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 10 or more carbon atoms in the ester portion is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, based on the total structural units constituting the vinyl polymer, from the viewpoint of improving the fluidity of the vinyl polymer.

The preferred range of the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 10 or more carbon atoms in the ester portion in the vinyl polymer can be set by appropriately combining the upper and lower limits described above. Specifically, the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 10 or more carbon atoms in the ester portion in the vinyl polymer is preferably 0.1 to 50 mass%, more preferably 1.0 to 45 mass%, even more preferably 2 to 40 mass% or more, and even more preferably 5 to 40 mass% or more, based on the total structural units constituting the vinyl polymer.

In order to appropriately increase the viscosity of the vinyl polymer, it is preferable that the vinyl polymer contains a relatively small proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 2 or less carbon atoms in the ester moiety, such as methyl (meth)acrylate and ethyl (meth)acrylate. Specifically, in the vinyl polymer, the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 2 or less carbon atoms in the ester moiety is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less, based on the total structural units constituting the vinyl polymer. Note that the vinyl polymer may not have structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 2 or less carbon atoms in the ester moiety. That is, the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 2 or less carbon atoms in the ester moiety in the vinyl polymer may be 0% by mass.

The vinyl polymer is particularly suitable in that it contains 0.1 to 50 mass% of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 10 or more carbon atoms in the ester moiety relative to the total structural units constituting the vinyl polymer, and the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 2 or less carbon atoms in the ester moiety is 20 mass% or less relative to the total structural units constituting the vinyl polymer, thereby ensuring the fluidity (i.e., low viscosity) of the vinyl polymer and improving workability, while providing the cured product obtained from the curable resin composition containing the vinyl polymer with excellent tensile properties, weather resistance, and heat resistance.

The method for introducing a crosslinkable functional group is not limited to the method of polymerizing a crosslinkable group-containing vinyl monomer, and other methods may be used. Examples of other methods for introducing a crosslinkable functional group include the following methods 1 and 2.
Method 1: A method of introducing a structural unit derived from an unsaturated carboxylic acid into a vinyl polymer, and reacting (addition reaction) a carboxyl group in the structural unit derived from the unsaturated carboxylic acid with a crosslinkable group-containing epoxy compound (preferably, a crosslinkable silyl group-containing epoxy compound). Method 2: A method of introducing a structural unit derived from an epoxy group-containing vinyl compound into a vinyl polymer, and reacting (addition reaction) an epoxy group in the structural unit derived from the epoxy group-containing vinyl compound with a crosslinkable group-containing amine compound (preferably, a crosslinkable silyl group-containing amine compound).

(Molecular weight characteristics)
The vinyl polymer preferably has a polystyrene-equivalent number average molecular weight (Mn) measured by GPC in the range of 10,000 to 300,000. When Mn is 10,000 or more, it is preferable in that when a cured product is produced from the vinyl polymer, the strength, weather resistance, and heat resistance of the cured product can be sufficiently increased. Also, when Mn of the vinyl polymer is 300,000 or less, good fluidity and coatability can be ensured.

From the viewpoint of strength, weather resistance, and heat resistance of the cured product, the Mn of the vinyl polymer is more preferably 15,000 or more, even more preferably 20,000 or more, even more preferably 25,000 or more, and even more preferably 30,000 or more. From the viewpoint of ensuring the flowability of the polymer, the upper limit of the Mn of the vinyl polymer is more preferably 200,000 or less, even more preferably 150,000 or less, even more preferably 100,000 or less, and even more preferably 70,000 or less. The preferred range of Mn of the vinyl polymer is more preferably 15,000 to 200,000, even more preferably 20,000 to 150,000, even more preferably 25,000 to 90,000, and even more preferably 30,000 to 70,000.

Furthermore, it is preferable that the weight average molecular weight (Mw) of the vinyl polymer in terms of polystyrene measured by GPC is in the range of 15,000 to 300,000. If the Mw is 15,000 or more, when a cured product is produced from the vinyl polymer, the strength, weather resistance, and heat resistance of the cured product can be sufficiently high. Furthermore, if the Mw of the vinyl polymer is 300,000 or less, good fluidity and coatability can be ensured.

From the viewpoint of strength, weather resistance, and heat resistance of the cured product, the Mw of the vinyl polymer is more preferably 20,000 or more, even more preferably 25,000 or more, even more preferably 30,000 or more, and even more preferably 35,000 or more. From the viewpoint of ensuring the flowability of the polymer, the upper limit of the Mw of the vinyl polymer is more preferably 200,000 or less, even more preferably 150,000 or less, and even more preferably 100,000 or less. The preferred range of the Mw of the vinyl polymer is more preferably 20,000 to 200,000, even more preferably 20,000 to 150,000, even more preferably 30,000 to 150,000, and even more preferably 30,000 to 100,000.

For vinyl polymers, the molecular weight distribution (Mw/Mn) obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn) is preferably 1.90 or less, more preferably 1.85 or less, even more preferably 1.80 or less, even more preferably 1.75 or less, even more preferably 1.70 or less, and even more preferably 1.65 or less, from the viewpoint of obtaining a cured product with excellent tensile properties (elongation at break, strength at break, etc.) and weather resistance. There is no particular restriction on the lower limit of the molecular weight distribution (Mw/Mn), but it may be, for example, 1.05 or more, or 1.10 or more.

(viscosity)
The viscosity of the vinyl polymer is preferably 50 to 1000 Pa·s. When the vinyl polymer has a viscosity within the above range, it can be a polymer having good fluidity and coatability while having high mechanical strength. From the viewpoint of obtaining a polymer having sufficiently high mechanical strength, the viscosity of the vinyl polymer is more preferably 60 Pa·s or more, even more preferably 70 Pa·s or more, even more preferably 80 Pa·s or more, and even more preferably 90 Pa·s or more. In addition, from the viewpoint of ensuring fluidity and coatability, the viscosity is more preferably 900 Pa·s or less, even more preferably 800 Pa·s or less, and even more preferably 600 Pa·s or less. The viscosity of the vinyl polymer is a value measured by an E-type viscometer at 25°C. Details of the viscosity measurement method follow the method described in the examples below.

(Structure of vinyl polymer)
The order of monomers in the vinyl polymer is not particularly limited. The vinyl polymer may be any of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer. Among these, the vinyl polymer is preferably a block copolymer, since it is easy to control the position where the crosslinkable functional group is introduced, and therefore it is easy to obtain a cured product having excellent tensile properties, weather resistance, and heat resistance.

(Block Copolymer)
When the vinyl polymer of the present disclosure is a block copolymer, the block copolymer (hereinafter also simply referred to as "block copolymer") may have two or more polymer blocks having different polymer compositions, and the structure is not particularly limited. A preferred example of the block copolymer is a vinyl polymer having a polymer block (A) having a crosslinkable functional group and a polymer block (B) having a different polymer composition from that of the polymer block (A).

Polymer block (A)
Examples of monomers constituting the polymer block (A) include the compounds exemplified as specific examples of monomers constituting vinyl polymers. Of these, the polymer block (A) preferably has a structural unit derived from a (meth)acrylic acid alkyl ester compound, and more preferably has at least a structural unit derived from a (meth)acrylic acid alkyl ester having an alkyl group having 2 to 18 carbon atoms.

In the polymer block (A), the proportion of structural units derived from (meth)acrylic acid alkyl ester compounds is preferably 50% by mass or more relative to the total structural units constituting the polymer block (A) from the viewpoint of obtaining a vinyl-based polymer having excellent mechanical properties and excellent weather resistance. From this viewpoint, the proportion of structural units derived from (meth)acrylic acid alkyl ester compounds in the polymer block (A) is more preferably 55% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit of the proportion of structural units derived from (meth)acrylic acid alkyl ester compounds in the polymer block (A) is, for example, 99% by mass or less, preferably 98% by mass or less, and more preferably 95% by mass or less, from the viewpoint of fully obtaining the improvement effect due to the introduction of crosslinkable functional groups.

In the polymer block (A), the proportion of structural units derived from a crosslinkable group-containing vinyl monomer (i.e., crosslinkable group-containing vinyl units) is preferably 1% by mass or more relative to the total structural units constituting the polymer block (A). By setting the proportion of crosslinkable group-containing vinyl units to 1% by mass or more, it is preferable in that mechanical strength can be sufficiently improved. The proportion of crosslinkable group-containing vinyl units in the polymer block (A) is preferably 2% by mass or more, and more preferably 5% by mass or more. On the other hand, from the viewpoint of ensuring the flexibility of the vinyl polymer, the upper limit of the crosslinkable group-containing vinyl units is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less relative to the total structural units constituting the polymer block (A).

The number average molecular weight (Mn) of the polymer block (A) measured by GPC in terms of polystyrene is preferably in the range of 1,000 to 80,000. If Mn is 1,000 or more, it is preferable in that when a cured product is produced using the block copolymer, the strength and durability of the cured product can be sufficiently increased. Also, if Mn is 80,000 or less, it is preferable in that good fluidity and coatability can be ensured.

From the viewpoint of the strength of the cured product, the Mn of the polymer block (A) is more preferably 2,000 or more, even more preferably 3,000 or more, even more preferably 3,500 or more, and even more preferably 4,000 or more. From the viewpoint of ensuring the fluidity of the block copolymer, the upper limit of the Mn of the polymer block (A) is more preferably 60,000 or less, even more preferably 40,000 or less, even more preferably 20,000 or less, and even more preferably 10,000 or less. The preferred range of the Mn of the polymer block (A) can be set by appropriately combining the above-mentioned upper and lower limits. The Mn of the polymer block (A) is more preferably 2,000 to 60,000, even more preferably 3,000 to 40,000, even more preferably 3,500 to 20,000, and even more preferably 4,000 to 10,000.

The weight average molecular weight (Mw) of the polymer block (A) measured by GPC in terms of polystyrene is preferably in the range of 1,200 to 100,000. If the Mw is 1,200 or more, it is preferable that the strength and durability of the cured product produced using the block copolymer can be sufficiently increased. If the Mw is 100,000 or less, it is preferable that good fluidity and coatability can be ensured.

From the viewpoint of the strength of the cured product, the Mw of the polymer block (A) is more preferably 2,000 or more, even more preferably 3,000 or more, even more preferably 4,000 or more, and even more preferably 5,000 or more. From the viewpoint of ensuring the fluidity of the block copolymer, the upper limit of the Mw of the polymer block (A) is more preferably 80,000 or less, even more preferably 60,000 or less, even more preferably 40,000 or less, and even more preferably 15,000 or less. The preferred range of the Mw of the polymer block (A) can be set by appropriately combining the above-mentioned upper and lower limits. The Mw of the polymer block (A) is more preferably 2,000 to 80,000, even more preferably 3,000 to 60,000, even more preferably 4,000 to 40,000, and even more preferably 5,000 to 15,000.

When a block copolymer has multiple polymer blocks (A), the number average molecular weight of the polymer block (A) represents the sum of the number average molecular weights of all the polymer blocks (A). For example, when a block copolymer is an (A)-(B)-(A) triblock copolymer consisting of polymer block (A)/polymer block (B)/polymer block (A), the "number average molecular weight of polymer block (A)" means the sum of the number average molecular weights of the two polymer blocks (A) contained in the block copolymer. The same applies to the weight average molecular weight and polymer block (B).

The molecular weight distribution (Mw/Mn) of the polymer block (A) is preferably 1.80 or less, more preferably 1.75 or less, even more preferably 1.70 or less, and even more preferably 1.50 or less, from the viewpoint of obtaining a cured product with excellent tensile properties (elongation at break, strength at break, etc.) and weather resistance. The lower limit of the molecular weight distribution (Mw/Mn) may be, for example, 1.05 or more, or 1.10 or more.

Polymer block (B)
Examples of the monomer constituting the polymer block (B) include the compounds exemplified as specific examples of the monomer constituting the vinyl polymer. Among the above-exemplified monomers, the polymer block (B) is preferably a polymer having a (meth)acrylic acid alkyl ester compound as the main structural unit, more preferably a polymer having a (meth)acrylic acid alkyl ester having an alkyl group with 2 to 18 carbon atoms in the ester moiety as the main structural unit, and even more preferably a polymer having a (meth)acrylic acid alkyl ester having an alkyl group with 4 to 18 carbon atoms in the ester moiety as the main structural unit, in that it can obtain a vinyl polymer having excellent flexibility.

In the polymer block (B), the proportion of structural units derived from (meth)acrylic acid alkyl ester compounds is preferably 50% by mass or more relative to the total structural units constituting the polymer block (B) from the viewpoint of obtaining a vinyl-based polymer with excellent mechanical properties. The proportion of structural units derived from (meth)acrylic acid alkyl ester compounds in the polymer block (B) is more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more.

When considering the fluidity of the block copolymer, it is preferable that the polymer block (B) has a structural unit derived from an alkyl acrylate ester having an alkyl group with 4 to 8 carbon atoms in the ester portion. Furthermore, when considering increasing compatibility with other polymers (e.g., polyoxyalkylene polymers) to be blended in a curable resin composition containing the block copolymer when preparing the curable resin composition, it is preferable that the polymer block (B) has a structural unit derived from an alkyl (meth)acrylate ester having an alkyl group with 10 or more carbon atoms in the ester portion, and it is more preferable that the polymer block (B) has a structural unit derived from an alkyl (meth)acrylate ester having an alkyl group with 10 to 18 carbon atoms in the ester portion.

In the polymer block (B), the proportion of structural units derived from an alkyl (meth)acrylate ester having an alkyl group with 4 to 8 carbon atoms in the ester portion is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total structural units constituting the polymer block (B), from the viewpoint of obtaining a block copolymer that fully exhibits fluidity and has excellent mechanical properties.

In addition, the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 10 or more carbon atoms (preferably 10 to 18 carbon atoms) in the ester portion is preferably 1% by mass or more, and more preferably 5% by mass or more, based on all structural units constituting polymer block (B), from the viewpoint of improving compatibility with other polymers. The upper limit is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less, and even more preferably 30% by mass or less, based on all structural units constituting polymer block (B).

The polymer block (B) may further have a crosslinkable functional group. When the polymer block (B) has a crosslinkable functional group, the crosslinkable functional group may be any of the groups exemplified as the crosslinkable functional group possessed by the vinyl polymer. From the viewpoint of forming a uniform crosslinked structure, it is preferable to concentrate the crosslinking points in the polymer block (A). From this viewpoint, it is preferable that the ratio of the structural units derived from the crosslinkable group-containing vinyl monomer to the total structural units constituting the polymer block (B) is less than the ratio of the structural units derived from the crosslinkable group-containing vinyl monomer to the total structural units constituting the polymer block (A).

Specifically, the proportion of structural units derived from a crosslinkable group-containing vinyl monomer (i.e., crosslinkable group-containing vinyl units) in polymer block (B) is preferably 15% by mass or less relative to all structural units constituting polymer block (B). If the proportion of crosslinkable group-containing vinyl units in polymer block (B) is 15% by mass or less, this is preferable in that the flexibility of the block copolymer can be sufficiently ensured. The proportion of crosslinkable group-containing vinyl units in polymer block (B) is preferably 10% by mass or less relative to all structural units constituting polymer block (B), more preferably 5% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less.

The number average molecular weight (Mn) of the polymer block (B) measured by GPC in terms of polystyrene is preferably in the range of 9,000 to 250,000. If Mn is 9,000 or more, when a cured product is produced using the block copolymer, the strength and durability of the cured product can be sufficiently high. Furthermore, if Mn is 250,000 or less, good fluidity and coatability can be ensured. Furthermore, by having Mn of the polymer block (B) in the above range, the molecular weight of the molecular chain portion corresponding to the distance between crosslinking points can be sufficiently ensured.

From the viewpoint of the strength of the cured product, the Mn of the polymer block (B) is more preferably 14,000 or more, even more preferably 19,000 or more, even more preferably 23,000 or more, and even more preferably 25,000 or more. From the viewpoint of ensuring the fluidity of the polymer, the upper limit of the Mn of the polymer block (B) is more preferably 150,000 or less, and even more preferably 100,000 or less. The preferred range of the Mn of the polymer block (B) can be set by appropriately combining the above-mentioned upper and lower limits. The Mn of the polymer block (B) is more preferably 14,000 to 150,000, even more preferably 19,000 to 100,000, and even more preferably 23,000 to 80,000.

The weight average molecular weight (Mw) of the polymer block (B) measured by GPC in terms of polystyrene is preferably in the range of 10,000 to 300,000. If the Mw is 10,000 or more, when a cured product is produced using the block copolymer, the strength and durability of the cured product can be sufficiently high. If the Mw is 300,000 or less, good fluidity and coatability can be ensured, and the molecular weight of the molecular chain portion corresponding to the distance between crosslinking points can be sufficiently ensured.

From the viewpoint of the strength of the cured product, the Mw of the polymer block (B) is more preferably 15,000 or more, even more preferably 20,000 or more, even more preferably 25,000 or more, and even more preferably 30,000 or more. From the viewpoint of ensuring the flowability of the polymer, the upper limit of the Mw of the polymer block (B) is more preferably 250,000 or less, and even more preferably 200,000 or less. The preferred range of the Mw of the polymer block (B) can be set by appropriately combining the above-mentioned upper and lower limits. The Mw of the polymer block (B) is more preferably 15,000 to 250,000, even more preferably 20,000 to 200,000, and even more preferably 30,000 to 200,000.

The molecular weight distribution (Mw/Mn) of the polymer block (B) is preferably 3.0 or less from the viewpoint of obtaining a polymer having excellent weather resistance. The molecular weight distribution of the polymer block (B) is more preferably 2.5 or less, even more preferably 2.2 or less, and even more preferably 2.0 or less. The lower limit of the molecular weight distribution of the polymer block (B) is not particularly limited, but from the viewpoint of ease of production, it is, for example, 1.05 or more.

Structure of block copolymer Examples of the structure of the block copolymer having polymer block (A) and polymer block (B) include (A)-(B) diblock consisting of polymer block (A) and polymer block (B), (A)-(B)-(A) triblock consisting of polymer block (A)/polymer block (B)/polymer block (A), (B)-(A)-(B) triblock consisting of polymer block (B)/polymer block (A)/polymer block (B), and (A)-(B)-(A)-(B)-(A) pentablock consisting of polymer block (A)/polymer block (B)/polymer block (A)/polymer block (B)/polymer block (A). The block copolymer may further have a polymer block (C) other than the polymer block (A) and the polymer block (B). Examples of the monomer constituting the polymer block (C) include the compounds exemplified as specific examples of the monomer constituting the present polymer.

Among these, the triblock copolymer is preferred, and the (A)-(B)-(A) triblock copolymer is more preferred, since the number of blocks is as small as possible to ensure ease of production while providing a polymer that exhibits excellent weather resistance. With such a structure, the polymer block (A) having a structural unit derived from a vinyl monomer containing a crosslinkable group acts as a crosslinking segment, making it easy to form a uniform crosslinked structure while ensuring the molecular weight between crosslinking points, and is therefore advantageous in that the mechanical strength and weather resistance of the resulting cured product can be increased.

In the block copolymer, the proportions of the polymer block (A) and the polymer block (B) are not particularly limited, but from the viewpoint of sufficiently introducing crosslinking points into the block copolymer to obtain a polymer with high mechanical strength and weather resistance, it is preferable that the proportion of the polymer block (A) is 2 parts by mass or more per 100 parts by mass of the total amount of the polymer block (A) and the polymer block (B). The proportion of the polymer block (A) is more preferably 4 parts by mass or more, even more preferably 6 parts by mass or more, even more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more per 100 parts by mass of the total amount of the polymer block (A) and the polymer block (B). The upper limit of the content of the polymer block (A) is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less per 100 parts by mass of the total amount of the polymer block (A) and the polymer block (B).

<Production of Block Copolymer>
The polymerization method for obtaining the block copolymer is not particularly limited as long as it has two or more polymer blocks. For example, in order to obtain a block copolymer with precisely controlled molecular weight and molecular weight distribution, various controlled polymerization methods such as living radical polymerization and living anionic polymerization can be used. In addition, the block copolymer may be produced by coupling polymers having functional groups. Among these, the production by living radical polymerization is preferable because the operation is simple, it can be applied to a wide range of monomers, and the content of metal components that may affect durability at high temperatures can be reduced, thereby obtaining a cured product with excellent heat resistance.

When producing a vinyl polymer by living radical polymerization, a known polymerization method can be used as the living radical polymerization method. Specific examples of living radical polymerization methods include exchange chain transfer mechanism type living radical polymerization method, bond-dissociation mechanism type living radical polymerization method, and atom transfer mechanism type living radical polymerization method. Of these, exchange chain transfer mechanism type living radical polymerization method is preferred because it can be applied to the widest range of vinyl monomers and has excellent polymerization controllability, and reversible addition-fragmentation chain transfer polymerization method (RAFT method) is particularly preferred from the viewpoint of ease of implementation.

In the RAFT method, polymerization proceeds via a reversible chain transfer reaction in the presence of a living radical polymerization control agent (RAFT agent) and a polymerization initiator. As the RAFT agent, various known RAFT agents such as dithioester compounds, xanthate compounds, trithiocarbonate compounds, and dithiocarbamate compounds can be used. Of these, dithioester compounds or trithiocarbonate compounds are preferably used, and trithiocarbonate compounds are more preferably used, in terms of excellent polymerization controllability of (meth)acrylic acid ester compounds. Examples of compounds having a trithiocarbonate group include S,S-dibenzyl trithiocarbonate, bis[4-(2,3-dihydroxypropoxycarbonyl)benzyl]trithiocarbonate, bis[4-(2-hydroxyethoxycarbonyl)benzyl]trithiocarbonate, and 1,4-bis(alkylsulfanylthiocarbonylsulfanylmethyl)benzene (e.g., 1,4-bis(n-dodecylsulfanylthiocarbonylsulfanylmethyl)benzene, etc.).

The RAFT agent may be a monofunctional agent having only one active site in one molecule, or a multifunctional agent having two or more active sites in one molecule. It is preferable to carry out the polymerization using a bifunctional RAFT agent, since this allows efficient production of an (A)-(B)-(A) triblock block copolymer consisting of polymer block (A)/polymer block (B)/polymer block (A). The amount of the RAFT agent used may be appropriately adjusted depending on the type of monomer and RAFT agent used, etc.

For example, when obtaining an (A)-(B)-(A) triblock material consisting of polymer block (A)/polymer block (B)/polymer block (A) by living radical polymerization using a bifunctional RAFT agent (e.g., S,S-dibenzyltrithiocarbonate), the target product can be obtained efficiently by a method including the following two-stage process as a polymerization process for polymerizing a vinyl monomer. That is, in the first step (first polymerization process), a vinyl monomer is polymerized in the presence of a RAFT agent and a polymerization initiator to obtain polymer block (A). Then, in the second step (second polymerization process), a vinyl monomer is polymerized in the presence of the polymer block (A) obtained in the first polymerization process and a polymerization initiator to form polymer block (B). This makes it possible to obtain an (A)-(B)-(A) triblock material consisting of polymer block (A)/polymer block (B)/polymer block (A). In addition, by using a similar method, it is also possible to obtain block copolymers with even higher order than triblock copolymers (for example, (A)-(B)-(A)-(B)-(A) pentablock copolymers).

As the polymerization initiator, known radical polymerization initiators such as azo compounds, organic peroxides, and persulfates can be used. Among these, azo compounds are preferred because they are safe to handle and less likely to cause side reactions during radical polymerization. Specific examples of azo compounds include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], and 2,2'-azobis(N-butyl-2-methylpropionamide). Only one type of polymerization initiator may be used, or two or more types may be used in combination. Furthermore, the polymerization initiator used in the first polymerization step and the polymerization initiator used in the second polymerization step may be the same or different.

The amount of polymerization initiator used is not particularly limited and can be set appropriately depending on the polymerization method employed. For example, in the case of the RAFT method, from the viewpoint of obtaining a polymer with a narrower molecular weight distribution, it is preferable to set the amount of polymerization initiator used per 1 mol of RAFT agent to 0.5 mol or less, and more preferably 0.4 mol or less. Furthermore, from the viewpoint of carrying out a stable polymerization reaction, the lower limit of the amount of polymerization initiator used is preferably 0.01 mol or more, and more preferably 0.05 mol or more, per 1 mol of RAFT agent. The amount of polymerization initiator used per 1 mol of RAFT agent is preferably 0.01 to 0.5 mol, and more preferably 0.05 to 0.4 mol.

In the case of the RAFT method, the polymerization reaction may be carried out in the presence of a chain transfer agent, such as an alkylthiol compound having 2 to 20 carbon atoms, if necessary. In addition, a dehydrating agent, such as trimethyl orthoacetate or triethyl orthoacetate, may be mixed into the reaction system if necessary.

The polymerization method of living radical polymerization is not particularly limited, and various methods such as solution polymerization, emulsion polymerization, mini-emulsion polymerization, suspension polymerization, and bulk polymerization can be appropriately adopted. For example, when the solution polymerization method is adopted, the polymerization reaction is carried out using a known polymerization solvent. As the polymerization solvent, various solvents can be used, for example, saturated hydrocarbon compounds, aromatic compounds, ester compounds, ketone compounds, alcohol compounds, ether compounds, nitrile compounds, water, etc. are included. As the polymerization solvent, it is preferable to use a solvent capable of dissolving the monomer, and it is more preferable to use an organic solvent capable of dissolving the monomer. Note that the polymerization solvent may be used alone or in combination of two or more types.

Specific examples of polymerization solvents include saturated hydrocarbon compounds such as hexane, heptane, and cyclohexane; aromatic compounds such as benzene, toluene, xylene, and anisole; ester compounds such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl formate, and methyl propionate; ketone compounds such as acetone, methyl ethyl ketone, and cyclohexanone; alcohol compounds such as methanol, ethanol, and 2-propanol; ether compounds such as tetrahydrofuran; and nitrile compounds such as acetonitrile. Other polymerization solvents that may be used include dimethylformamide, dimethylsulfoxide, and water. As the polymerization solvent, it is preferable to use a solvent capable of dissolving the monomer. The polymerization solvent may be used alone or in combination of two or more.

The amount of polymerization solvent used is preferably 5 to 200 parts by mass, and more preferably 10 to 100 parts by mass, per 100 parts by mass of the total amount of monomers used in the polymerization reaction. Using 100 parts by mass or less of polymerization solvent is preferable because it allows a high polymerization rate to be achieved in a short period of time. Using 10 parts by mass or more of polymerization solvent is also preferable because it allows efficient removal of polymerization heat and prevents an increase in reaction temperature.

The method of feeding each raw material may be a batch-type initial lump-sum feeding in which all raw materials are fed at once, a semi-continuous feeding in which at least some of the raw materials are fed continuously into the reactor, or a continuous polymerization method in which all raw materials are fed continuously and the product is simultaneously continuously withdrawn from the reactor.

In terms of being able to easily obtain the vinyl polymer of the present disclosure, it is preferable that in the polymerization step of polymerizing the vinyl monomer, polymerization is performed while continuously or intermittently supplying at least a portion of the total amount of the crosslinkable group-containing vinyl monomer into the reactor. This method is believed to be able to suppress the variation in the number of crosslinkable functional groups per polymer molecule, and to introduce a uniform number of crosslinkable functional groups into each polymer. In other words, it is believed that the proportion of molecules in which more crosslinkable functional groups than the average number of crosslinkable functional groups have been introduced, molecules in which the number of crosslinkable functional groups is less than the average number, and molecules that do not have crosslinkable functional groups can be reduced, relative to the average number of crosslinkable functional groups in one polymer molecule. This makes it possible to suppress the variation in the crosslinked structure when the vinyl polymer is crosslinked, and as a result, a cured product with excellent weather resistance and heat resistance can be obtained.

When obtaining an (A)-(B)-(A) triblock consisting of polymer block (A)/polymer block (B)/polymer block (A) as a vinyl polymer, for the reasons mentioned above, in a method including the above-mentioned first and second polymerization steps, it is preferable to carry out polymerization in the first polymerization step while continuously or intermittently supplying at least a portion of the total amount of crosslinkable group-containing vinyl monomer used to produce polymer block (A) into a reactor. In this case, crosslinkable functional groups can be introduced into polymer blocks (A) located at both ends of the vinyl polymer while suppressing the variation in the number of crosslinkable functional groups between molecules. This makes it possible to obtain a cured product that exhibits excellent weather resistance and heat resistance.

When the crosslinkable group-containing vinyl monomer is continuously or intermittently fed into the reactor during the production of the polymer block (A), all of the crosslinkable group-containing vinyl monomer used in the production of the polymer block (A) may be fed into the reactor continuously or intermittently after the start of polymerization (i.e., after the addition of the polymerization initiator). Alternatively, a portion of the crosslinkable group-containing vinyl monomer used in the production of the polymer block (A) may be charged into the reactor before the start of polymerization (i.e., before the addition of the polymerization initiator), and the remaining crosslinkable group-containing vinyl monomer may be fed into the reactor continuously or intermittently after the start of polymerization. In terms of the high effect of equalizing the number of crosslinkable functional groups per polymer molecule between the molecules, it is preferable to feed a portion of the crosslinkable group-containing vinyl monomer used in the production of the polymer block (A) into the reactor before the start of polymerization, and feed the remainder into the reactor continuously or intermittently after the start of polymerization. In the following, among the vinyl monomers used in the production of polymer block (A), the monomer charged into the reactor before the start of polymerization is also referred to as the "initial charge monomer", and the monomer continuously or intermittently supplied to the reactor after the start of polymerization is also referred to as the "continuously supplied monomer".

The ratio of the initially charged monomer to the continuously supplied monomer of the crosslinkable group-containing vinyl monomer used in the production of the polymer block (A) is preferably 10 to 100% by mass of the continuously supplied monomer in the total amount of the crosslinkable group-containing vinyl monomer used in the production of the polymer block (A). From the viewpoint of making the number of crosslinkable group-containing vinyl monomers introduced into each molecule of the polymer block (A) uniform, the ratio of the continuously supplied monomer in the total amount of the crosslinkable group-containing vinyl monomer used in the production of the polymer block (A) is more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 60% by mass or more. In addition, the ratio of the continuously supplied monomer in the total amount of the crosslinkable group-containing vinyl monomer used in the production of the polymer block (A) is more preferably 95% by mass or less, even more preferably 90% by mass or less.

The supply mode of the continuously supplied monomer is not particularly limited as long as the crosslinkable group-containing vinyl monomer can be supplied into the reactor over a predetermined time period after the start of polymerization. For example, the crosslinkable group-containing vinyl monomer can be supplied into the reactor continuously (i.e., without interruption) or intermittently (i.e., with interruptions and continuity). In order to introduce the crosslinkable group-containing vinyl monomer more uniformly into each molecule of the polymer block (A), it is preferable that the supply mode of the crosslinkable group-containing vinyl monomer after the start of polymerization be continuous supply.

The timing for starting the continuous or intermittent supply of the crosslinkable group-containing vinyl monomer may be simultaneous with the start of polymerization, or after a predetermined time has elapsed since the start of polymerization. From the viewpoint of introducing the crosslinkable group-containing vinyl unit into the end of the vinyl polymer and thereby obtaining a cured product with excellent weather resistance and heat resistance, it is preferable to start the continuous or intermittent supply of the crosslinkable group-containing vinyl monomer simultaneously with or immediately after the start of polymerization. When supplying the crosslinkable group-containing vinyl monomer into the reactor after the start of polymerization, it is preferable to supply the crosslinkable group-containing vinyl monomer over a period of, for example, 10 minutes to 8 hours, and to supply it over a period of 30 minutes to 6 hours.

The reaction temperature and reaction time in the polymerization reaction can be appropriately set depending on the type of polymerization method employed and the types of monomers and polymerization solvents used. For example, in the case of the RAFT method, the reaction temperature is preferably 40°C or higher and 100°C or lower, more preferably 45°C or higher and 90°C or lower, and even more preferably 50°C or higher and 80°C or lower. A reaction temperature of 40°C or higher is preferred in that the polymerization reaction can proceed smoothly, and a reaction temperature of 100°C or lower is preferred in that side reactions can be suppressed and restrictions on the initiators and polymerization solvents that can be used are relaxed. The reaction time is, for example, 1 hour or higher and 48 hours or lower, and preferably 2 hours or higher and 24 hours or lower.

By the above polymerization, a solution containing a vinyl polymer is obtained as a polymer-containing solution. The polymer-containing solution obtained by polymerization may be subjected to a known solvent removal process, thereby isolating and/or purifying the vinyl polymer. In addition, after carrying out the following reaction steps as necessary, the obtained polymer may be isolated and/or purified. The process for isolating and purifying the polymer may be carried out according to a known method.

If the vinyl polymer obtained by the above polymerization has a thiocarbonylthio group derived from the RAFT agent, a step of reacting the vinyl polymer with a nucleophile (hereinafter also referred to as a "post-treatment step") may be carried out. By reacting the nucleophile with the thiocarbonylthio group of the vinyl polymer, the thiocarbonylthio group is converted to a thiol group, and it is presumed that the thiol group reacts (Michael addition reaction) with unreacted monomers remaining in the polymerization system (for example, acrylate compounds in the reaction system), thereby obtaining a vinyl polymer from which the thiocarbonylthio group has been removed.

Nucleophiles include ammonia, primary and/or secondary amine compounds, alkali metal alkoxides, hydroxides, and thiols. Among these, primary and/or secondary amine compounds are preferably used as nucleophiles in terms of reactivity.

The amount of nucleophile used is preferably such that the molar equivalent of the nucleophile relative to the thiocarbonylthio group is 2 to 90 mol equivalents. From the viewpoint of reaction efficiency, the amount of nucleophile used is preferably 2.5 mol equivalents or more relative to the thiocarbonylthio group, more preferably 3 mol equivalents or more, and even more preferably 3.5 mol equivalents or more. In addition, from the viewpoint of reducing the effect of odor due to unreacted nucleophile, the amount of nucleophile used is preferably 75 mol equivalents or less relative to the thiocarbonylthio group, more preferably 60 mol equivalents or less, and even more preferably 50 mol equivalents or less.

The reactor used in the reaction of the thiocarbonylthio group with the nucleophile may be a known reactor such as a batch reactor or a tubular reactor. The reaction temperature is preferably 10°C or higher, more preferably 15°C or higher, and even more preferably 25°C or higher in order to increase the reaction efficiency. In addition, in order to prevent side reactions (e.g., nucleophilic reactions to the polymer main chain, etc.), the reaction temperature is preferably 80°C or lower, more preferably 60°C or lower, and even more preferably 50°C or lower. The reaction pressure is usually normal pressure, but may be increased or decreased as necessary. The reaction time is preferably 1 hour or more, more preferably 2 hours or more, in terms of reaction efficiency. In addition, the upper limit of the reaction time is preferably 48 hours or less, more preferably 24 hours or less, in terms of suppressing side reactions such as nucleophilic reactions to the polymer main chain. When a polymer solution is obtained by the above reaction, the polymer can be isolated by subjecting the polymer solution to a known desolvation treatment.

《Curable resin composition》
The vinyl polymer of the present disclosure has high weather resistance and is suitable for applications such as sealants, adhesives, pressure-sensitive adhesives, and paints. The vinyl polymer of the present disclosure can be used alone for applications such as sealants, adhesives, pressure-sensitive adhesives, and paints, but may also be used as an embodiment of a curable resin composition containing various components such as known additives as necessary. For example, a curable resin composition can be obtained by blending a necessary crosslinking agent, a curing accelerator (also called a curing catalyst), other polymers having crosslinkable functional groups, etc., depending on the type of crosslinkable functional group possessed by the vinyl polymer. In addition, a cured product according to the application can be obtained by molding the curable resin composition and subjecting it to heat treatment or the like as necessary.

Other polymers having crosslinkable functional groups Examples of other polymers having crosslinkable functional groups include hydrocarbon polymers such as polyoxyalkylene polymers having crosslinkable functional groups, polyester polymers having crosslinkable functional groups, polyurethane polymers having crosslinkable functional groups, polybutadiene polymers having crosslinkable functional groups, hydrogenated polybutadiene polymers having crosslinkable functional groups, and polyisobutylene polymers having crosslinkable functional groups; polyamide polymers; bisphenol polymers, etc. Among these, in terms of excellent mechanical properties of the cured product, it is preferable that the curable resin composition of the present disclosure contains a polyoxyalkylene polymer having a crosslinkable functional group together with the vinyl polymer of the present disclosure. Examples of the crosslinkable functional groups possessed by the other polymers include the groups exemplified as the crosslinkable functional groups that may be possessed by the vinyl polymer of the present disclosure.

Examples of polyoxyalkylene polymers having a crosslinkable functional group (hereinafter also referred to as "crosslinkable polyoxyalkylene polymers") include polymers having a repeating unit represented by the following formula (2).
-O-R ⁴ -...(2)
(In formula (2), ^R4 represents a divalent hydrocarbon group.)

Examples of ^R4 in the above formula (2) include the following structures.
-( _CH2 ) _m- (m is an integer from 1 to 10)
・-CH(CH ₃ )CH ₂ -
・-CH(C ₂ H ₅ )CH ₂ -
・-C(CH ₃ ) ₂ CH ₂ -
The crosslinkable polyoxyalkylene polymer may contain one or a combination of two or more of the above repeating units. Among these, -CH(CH ₃ )CH ₂ - is preferred from the viewpoint of excellent workability.

As the crosslinkable functional group possessed by the crosslinkable polyoxyalkylene polymer, a crosslinkable silyl group is preferred in terms of excellent compatibility with the vinyl polymer of the present disclosure, excellent mechanical properties of the cured product, and excellent weather resistance, and an alkoxysilyl group is more preferred in terms of ease of controlling reactivity.

The method for producing a crosslinkable polyoxyalkylene polymer is not particularly limited, but examples include a polymerization method using the corresponding epoxy compound or diol compound as a raw material, an alkali catalyst (e.g., KOH, etc.), a polymerization method using a transition metal compound-porphyrin complex catalyst, a polymerization method using a composite metal cyanide complex catalyst, and a polymerization method using phosphazene.

The average number of crosslinkable silyl groups contained in one molecule of the crosslinkable polyoxyalkylene polymer is preferably in the range of 1 to 4, and more preferably in the range of 1.5 to 3, from the viewpoint of the mechanical properties and adhesiveness of the cured product. The position of the crosslinkable silyl group contained in the crosslinkable polyoxyalkylene polymer is not particularly limited, and can be in the side chain and/or at the end of the polymer. The crosslinkable polyoxyalkylene polymer to be blended in the curable resin composition may be either a linear polymer or a branched polymer. These may also be used in combination.

The number average molecular weight (Mn) of the crosslinkable polyoxyalkylene polymer measured by GPC in terms of polystyrene is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more, from the viewpoint of mechanical properties. The upper limit of Mn is preferably 60,000 or less, more preferably 50,000 or less, and even more preferably 40,000 or less, from the viewpoint of achieving low viscosity and improving workability when applying the curable resin composition. The range of Mn is preferably 5,000 to 60,000, more preferably 10,000 to 60,000, and even more preferably 15,000 to 50,000.

Commercially available cross-linkable polyoxyalkylene polymers may be used. Specific examples include "MS Polymer S203", "MS Polymer S303", "MS Polymer S810", "Silyl SAX510", "Silyl SAX220", "Silyl SAT200", "Silyl SAT350", "Silyl EST280" and "Silyl SAT30" manufactured by Kaneka Corporation, and "Exestar ES-S2410", "Exestar ES-S2420", "Exestar ES-S3430" and "Exestar ES-S4530" (all trade names) manufactured by AGC.

When the curable resin composition contains a crosslinkable polyoxyalkylene polymer, the content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, based on 100 parts by mass of the total amount of the vinyl polymer and the crosslinkable polyoxyalkylene polymer of the present disclosure. By setting the content of the crosslinkable polyoxyalkylene polymer within the above range, a cured product with high mechanical properties can be obtained. In addition, from the viewpoint of obtaining a cured product exhibiting excellent weather resistance, the upper limit of the content of the crosslinkable polyoxyalkylene polymer is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less, based on 100 parts by mass of the total amount of the vinyl polymer and the crosslinkable polyoxyalkylene polymer of the present disclosure.

The mass ratio of the vinyl polymer and the crosslinkable oxyalkylene polymer of the present disclosure, expressed as vinyl polymer/oxyalkylene polymer, is preferably 5/95 to 95/5, more preferably 10/90 to 90/10, and even more preferably 15/85 to 85/15.

・Cross-linking agent (hardening agent)
Examples of the crosslinking agent (curing agent) include an epoxy compound having two or more epoxy groups, an isocyanate compound having two or more isocyanate groups, an aziridine compound having two or more aziridinyl groups, an oxazoline compound having an oxazoline group, a metal chelate compound, a butylated melamine compound, etc. When a crosslinking agent is blended, among these, the epoxy compound, the isocyanate compound, and the aziridine compound are preferred, and among these, the isocyanate compound is preferred in that a cured product having good physical properties under high temperature conditions can be obtained.

When the curable resin composition contains a crosslinking agent, the content is usually 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the vinyl polymer and polyoxyalkylene polymer of the present disclosure. The content of the crosslinking agent is preferably 0.03 parts by mass to 5 parts by mass, and more preferably 0.05 parts by mass to 2 parts by mass.

・Cure accelerator (curing catalyst)
As the curing accelerator (curing catalyst), known compounds such as tin-based catalysts, titanium-based catalysts, and tertiary amines can be used. Among these, examples of tin-based catalysts include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetonate, and dioctyltin dilaurate. Specific examples include products sold by Nitto Kasei Corporation under the trade names "Neostan U-28,""NeostanU-100,""NeostanU-200,""NeostanU-220H,""NeostanU-303," and "SCAT-24."
Examples of titanium catalysts include tetraisopropyl titanate, tetra n-butyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethyl acetylacetonate, dibutoxytitanium diacetylacetonate, diisopropoxytitanium diacetylacetonate, titanium octylene glycolate, and titanium lactate.
Examples of tertiary amines include triethylamine, tributylamine, triethylenediamine, hexamethylenetetramine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), diazabicyclononene (DBN), N-methylmorpholine, and N-ethylmorpholine.

The amount of the curing accelerator is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 2 parts by mass, per 100 parts by mass of the total amount of the vinyl polymer and polyoxyalkylene polymer of the present disclosure.

Other components that can be added to the curable resin composition include, in addition to those mentioned above, for example, plasticizers, packing materials (also called fillers), pigments, adhesion promoters, dehydrating agents, anti-aging agents, UV absorbers, crosslinking agents (also called curing agents), and oils.

Plasticizers include liquid polyurethane resin, polyester-based plasticizers obtained from dicarboxylic acid and diol; etherified or esterified products of polyalkylene glycols such as polyethylene glycol and polypropylene glycol; polyether-based plasticizers such as sugar-based polyethers obtained by addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to sugar polyhydric alcohols such as sucrose, followed by etherification or esterification; polystyrene-based plasticizers such as poly-α-methylstyrene; and poly(meth)acrylates that do not have crosslinkable functional groups. Of these, poly(meth)acrylates that do not have crosslinkable functional groups are preferred in terms of durability such as weather resistance of the cured product. Of these, polymers with Mw in the range of 1,000 to 7,000 and a glass transition temperature of -30°C or lower are preferred as plasticizers.

The amount of plasticizer used is preferably in the range of 0 to 100 parts by mass, may be in the range of 0 to 90 parts by mass, or may be in the range of 10 to 90 parts by mass, relative to 100 parts by mass of the total amount of the vinyl polymer and polyoxyalkylene polymer of the present disclosure.

Fillers include light calcium carbonate with an average particle size of about 0.02 to 2.0 μm, heavy calcium carbonate with an average particle size of about 1.0 to 5.0 μm, titanium oxide, carbon black, synthetic silicic acid, talc, zeolite, mica, silica, calcined clay, kaolin, bentonite, aluminum hydroxide, barium sulfate, glass balloons, silica balloons, and polymethyl methacrylate balloons. These fillers improve the mechanical properties of the cured material, and can increase tensile strength and tensile elongation.

Among these, preferred fillers are light calcium carbonate, heavy calcium carbonate, and titanium oxide, which are effective in improving physical properties, and a mixture of light calcium carbonate and heavy calcium carbonate is more preferred. The amount of filler to be blended is preferably 20 to 300 parts by mass, and more preferably 50 to 200 parts by mass, per 100 parts by mass of the total amount of the vinyl polymer and polyoxyalkylene polymer of the present disclosure. When a mixture of light calcium carbonate and heavy calcium carbonate is used, the ratio of light calcium carbonate/heavy calcium carbonate is preferably in the range of 90/10 to 50/50 by mass. Titanium oxide, carbon black, or the like may be blended as a pigment in the curable resin composition.

Adhesion promoters include aminosilanes such as those manufactured by Shin-Etsu Silicones under the trade names "KBM602", "KBM603", "KBE602", "KBE603", "KBM902" and "KBM903" and those manufactured by Dow Corning Toray under the trade name "SH6020". Dehydrating agents include methyl orthoformate, methyl orthoacetate and vinylsilane.

As the anti-aging agent, ultraviolet absorbers such as benzophenone compounds, benzotriazole compounds, and anilide oxalates, light stabilizers such as hindered amine compounds, antioxidants such as hindered phenols, heat stabilizers, and mixtures of these can be used.

Examples of ultraviolet absorbers include BASF's Tinuvin 571, Tinuvin 1130, and Tinuvin 327. Examples of light stabilizers include BASF's Tinuvin 292, Tinuvin 144, and Tinuvin 123, and Sankyo's Sanol 770. Examples of heat stabilizers include BASF's Irganox 1135, Irganox 1520, and Irganox 1330. In addition, BASF's Tinuvin B75, a mixture of ultraviolet absorber, light stabilizer, and heat stabilizer, may be used.

For the purpose of adjusting the performance, coatability, processability, etc. of the curable resin composition containing the vinyl polymer of the present disclosure, other thermoplastic resins, etc. may be blended into the curable resin composition. Specific examples of thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, styrene resins such as polystyrene, vinyl resins such as polyvinyl chloride, polyester resins, polyamide resins, etc. Also, known elastomers may be blended.

The curable resin composition of the present disclosure can be prepared as a one-component curable resin composition in which all ingredients are mixed in advance and stored in a sealed container, and which hardens after application by absorbing moisture in the air. It can also be prepared as a two-component curable resin composition in which ingredients such as a curing catalyst, filler, plasticizer, and water are mixed separately as a curing agent, and the curing agent and resin composition are mixed before use. Of these, the one-component type is more preferred in that it is easy to handle and can prevent mixing errors during application.

The curable resin composition containing the vinyl polymer of the present disclosure exhibits good fluidity when heated from room temperature (25°C) to about 150°C. Therefore, it can be applied to various coating processes, as well as molding processes using various methods such as extrusion molding, injection molding, and casting.

Below, the present disclosure will be specifically explained based on examples, but the present disclosure is not limited to these examples. In the following, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Details of the analysis methods for the polymers obtained in the synthesis examples, comparative synthesis examples, production examples, and comparative production examples are as follows.

<Analysis method for vinyl polymers>
<Molecular weight measurement>
Using a gel permeation chromatograph (model name "HLC-8320", manufactured by Tosoh Corporation), the weight average molecular weight (Mw) and number average molecular weight (Mn) were obtained in terms of polystyrene under the following conditions. The molecular weight distribution (Mw/Mn) was calculated from the obtained values.
Measurement conditions Column: Tosoh Corporation TSKgel SuperMultiporeHZ-M x 4 Column temperature: 40°C
Eluent: Tetrahydrofuran Detector: RI

<Viscosity measurement>
The E-type viscosity was measured under the following conditions using a TVE-20H viscometer (cone/plate type, manufactured by Toki Sangyo Co., Ltd.).
Measurement conditions: Cone shape: angle 1°34', radius 24 mm (less than 10 Pa·s)
Angle 3°, radius 7.7mm (10Pa・s or more)
Temperature: 25℃±0.5℃

<Gas Chromatography (GC) Measurement>
Measurement conditions Column: Capillary column Agilent CP-Wax52CB (60 m x 0.32 mm ID, df = 0.5 μm) and Agilent DB-1 (30 m x 0.32 mm ID, df = 1.0 μm)
Solvent: Tetrahydrofuran Column temperature: 50°C (5 min), 7°C/min, 230°C (5 min)

<Measurement of Non-volatile Concentration of Polymerization Solution>
Approximately 0.5 g of a sample was placed in a weighing bottle whose weight had been measured in advance [weight of weighing bottle = B (unit: g)] and accurately weighed together with the weighing bottle [weight of sample and weighing bottle before drying = W0 (unit: g)]. The sample together with the weighing bottle was then placed in a hot air circulating dryer and dried at 155°C for 45 minutes, and the weight after drying was measured together with the weighing bottle [weight of sample and weighing bottle after drying = W1 (unit: g)]. The mass of non-volatile content in the sample [X (unit: g)] was then calculated using the following mathematical formula (2):
X=(W1-B)/(W0-B)...(2)

<Average Number of Crosslinkable Silyl Groups per Vinyl Polymer Molecule>
The average number of crosslinkable silyl groups (alkoxysilyl groups) (hereinafter, also referred to as "f(Si)") was calculated using the following formula from the amount (parts by mass) of monomers having crosslinkable silyl groups when the total amount of monomers used in the synthesis of the vinyl polymer was taken as 100 parts by mass.
f(Si)={amount of crosslinkable silyl group-containing monomer/(molecular weight of crosslinkable silyl group-containing monomer×100/Mn)}

<Recovery rate>
The recovery rate [%] of the cured vinyl polymer was determined by the following procedure.
100 parts of vinyl polymer, 70 parts of methyl ethyl ketone, and 20 parts of propylene glycol methyl ether acetate were mixed and dissolved at room temperature, and then 1 part of curing catalyst U-220H (dibutyltin diacetylacetonate, Neostan U-220H (manufactured by Nitto Kasei Co., Ltd.)) was added and mixed to prepare a mixed solution. This mixed solution was slowly poured into a box-shaped container made of a 2 mm thick Teflon (registered trademark) sheet so that the thickness of the dried film would be 2 mm, and the mixture was left to stand at 23°C and 50% RH for more than one week to obtain a cured sheet. A dumbbell for tensile testing (JIS K 6251 No. 2 type) was prepared from the cured sheet, and this was used as a test piece. Using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation), the test piece was stretched at a rate of 5 mm/min so that the gauge length (dumbbell No. 2 type: 20 mm) became 32 mm, and was held for 24 hours. Next, the test piece removed from the tensile tester was placed on a 2 mm thick Teflon (registered trademark) sheet, and after 1 hour, the gauge length ( _L2 ) was measured. The measurement was performed in an environment of 23°C and 50% RH. The recovery rate was calculated by the following formula when the test piece could be elongated under the above measurement conditions and recovery behavior was observed in the test piece removed from the tensile tester.
Restoration rate [%] = (L ₁ - _{L 2} )/(L ₁ - _{L 0} ) x 100
Where L ₀ : Gauge length before stretching [mm]
_L1 : Gauge length when stretched [mm]
_L2 : Gauge length [mm] 1 hour after removal from the tensile tester
Here, L ₀ =20 [mm], L ₁ =32 [mm].

<Tensile properties>
The tensile properties were measured using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation) using a tensile tester dumbbell (JIS K 6251 Type 2) prepared in the same manner as in the measurement of the recovery rate. The breaking elongation (El, unit %), breaking strength (Ts, unit MPa), and strength at 50% elongation (M50, unit MPa) were measured under conditions of a temperature of 23°C, 50% RH, and a tensile speed of 200 mm/min.

<Production and Evaluation of Vinyl Polymers>
<Production of polymer block (A)>
Synthesis Example 1: Production of Polymer a-1 In a 1 L flask equipped with a stirrer and a thermometer, S,S-dibenzyl trithiocarbonate (hereinafter also referred to as "DBTTC") (6.7 parts), 2,2'-azobis(2,4-dimethylvaleronitrile) (hereinafter also referred to as "V-65") (0.29 parts), n-butyl acrylate (hereinafter also referred to as "BA") (59.0 parts), ethyl acrylate (hereinafter also referred to as "EA") (3.9 parts), n-tetradecyl acrylate (hereinafter also referred to as "TDA") (15.7 parts), methyldimethoxysilylpropyl methacrylate (hereinafter also referred to as "DMS") (5.4 parts), ethyl acetate (85.1 parts) and trimethyl orthoacetate (hereinafter also referred to as "MOA") (21.3 parts) were charged, thoroughly degassed by nitrogen bubbling, and the temperature was raised to 58 ° C. to initiate polymerization. After the polymerization was started, DMS (16.1 parts) was continuously added dropwise to the 1 L flask over 2 hours from immediately after the start of polymerization. After 2 hours from the start of polymerization, the temperature was raised to 70° C. over 1 hour, and the reaction was continued at 70° C. for another 4 hours. Thereafter, the reaction was stopped by cooling to room temperature, and a solution containing polymer a-1 was obtained.
The molecular weight of the obtained polymer a-1 was measured by GPC (gel permeation chromatography) (polystyrene equivalent) to be Mn 4,700, Mw 6,130, and Mw/Mn 1.30. The reaction rates of each monomer measured by gas chromatography (GC) were BA: 80%, EA: 87%, TDA: 83%, and DMS: 100%. The non-volatile content of the polymerization solution measured by the above method was 43.1%.

[Synthesis Examples 2 to 17 and Comparative Synthesis Examples 1 to 3] Preparation of Polymers a-2 to a-17 and ca-1 to ca-3 Polymers a-2 to a-17 and ca-1 to ca-3 were obtained by the same operation as in Synthesis Example 1, except that the raw materials were used as shown in Tables 1 and 2. The molecular weight of each polymer, the non-volatile concentration of the polymerization solution, and the reaction rate of each monomer were measured and shown in Tables 1 and 2. In Tables 1 and 2, "initial charge monomer" represents the monomer charged into a 1 L flask (reactor) before the start of polymerization, and "continuously supplied monomer" represents the monomer continuously supplied dropwise into a 1 L flask (reactor) over 2 hours immediately after the start of polymerization.

[Synthesis Example 18] Production of Polymer a-18 A 1L flask equipped with a stirrer and a thermometer was charged with DBTTC (6.7 parts), BA (49.0 parts), EA (4.0 parts), TDA (25.0 parts), p-styryltrimethoxysilane (hereinafter also referred to as "STMS") (5.5 parts), ethyl acetate (24.0 parts) and MOA (12.0 parts), and further added one-third of V-65 (0.77 parts) to a 1L flask, thoroughly degassed by nitrogen bubbling, and heated to 75 ° C. to initiate polymerization. After the start of polymerization, three divided amounts of V-65 (0.77 parts) were added to the 1L flask at 1.0 and 2.0 hours from the start of polymerization. In addition, STMS (16.5 parts) was divided into four and added at 0.5, 1.0, 1.5 and 2.0 hours from the start of polymerization, respectively. Two hours after the start of polymerization, the temperature was raised to 80° C. over one hour, and the reaction was continued for another two hours at 80° C. Thereafter, the reaction was stopped by cooling to room temperature, and a solution containing polymer a-18 was obtained.

The abbreviations for the compounds in Tables 1 and 2 (same for Tables 3 to 8) are as follows:
BA: n-butyl acrylate TDA: n-tetradecyl acrylate SA: octadecyl acrylate (stearyl acrylate)
EA: Ethyl acrylate MMA: Methyl methacrylate DMS: Methyl dimethoxysilylpropyl methacrylate TMS: Trimethoxysilylpropyl methacrylate MTMS: Trimethoxysilylmethyl methacrylate STMS: p-Styryltrimethoxysilane DBTTC: S,S-Dibenzyl trithiocarbonate V-65: 2,2'-Azobis(2,4-dimethylvaleronitrile)
MOA: trimethyl orthoacetate

<Production of Triblock Copolymer>
[Synthesis Example 19] Production of triblock copolymer b-1 A 1L flask equipped with a stirrer and a thermometer was charged with the solution containing the polymer a-1 obtained in Synthesis Example 1 (47% purity, 5.3 parts (11.3 parts x 0.47 = 5.3 parts) as polymer a-1), BA (71.0 parts), EA (4.8 parts), TDA (19.0 parts), 2,2'-azobis (2-methylbutyronitrile) (hereinafter, also referred to as "ABN-E") (0.157 parts), ethyl acetate (16.0 parts) and MOA (4.0 parts), and the solution was thoroughly degassed by nitrogen bubbling, and polymerization was started in a thermostatic bath at 70 ° C. Six hours after the start of polymerization, the reaction was stopped by cooling to room temperature to obtain a solution containing triblock copolymer b-1. The "purity" is a value (unit: %) represented by the ratio of the total amount of monomers to the total amount charged at the time of polymerization (the total amount of monomers, control agent, initiator and solvent).
The molecular weight of the obtained triblock copolymer b-1 was Mn 70,000, Mw 97,000, and Mw/Mn 1.39. The reaction rates of each monomer measured by gas chromatography (GC) were BA: 92%, EA: 88%, and TDA: 90%.
The obtained triblock copolymer b-1 has a polymer block (A) consisting of BA, EA, TDA, and DMS, and a polymer block (B) consisting of BA, EA, and TDA, and is a triblock copolymer having a block structure of (A)-(B)-(A) (polymer block (A)/polymer block (B)/polymer block (A)).

[Synthesis Examples 20 to 47 and Comparative Synthesis Examples 4 to 6] Production of triblock copolymers b-2 to b-29 and cb-1 to cb-3 Triblock copolymers b-2 to b-29 and cb-1 to cb-3 were obtained by the same procedure as in Synthesis Example 19, except that the raw materials were used as shown in Tables 3 and 4. The molecular weight of each polymer and the reaction rate of each monomer were measured and are shown in Tables 3 and 4.

In Tables 3 and 4, the abbreviations for the compounds other than those listed in Tables 1 and 2 represent the following.
ABN-E: 2,2'-azobis(2-methylbutyronitrile)

<Production of Pentablock Copolymer>
[Synthesis Example 48] Preparation of pentablock copolymer c-1 The solution containing triblock copolymer b-1 obtained in Synthesis Example 19 (98.88 parts) and MOA (0.23 parts) were charged, thoroughly degassed by nitrogen bubbling, and heated to 60 ° C. After the internal temperature was stabilized at 60 ° C., ABN-E (0.015 parts) was added to start polymerization. DMS (1.12 parts) was divided into four portions and added at 0 hours, 0.5 hours, 1.0 hours, and 1.5 hours after the start of polymerization. After 7 hours from the start of polymerization, the reaction was stopped by cooling to room temperature to obtain a solution containing pentablock copolymer c-1. The molecular weight of the pentablock copolymer c-1 was Mn 69,000, Mw 103,000, and Mw / Mn 1.49. The reaction rates of the individual monomers measured by gas chromatography (GC) were as follows: BA: 92%, EA: 91%, TDA: 90%, and DMS: 99%.
The obtained pentablock copolymer c-1 had a polymer block (A) consisting of BA, EA, TDA and DMS, and a polymer block (B) consisting of BA, EA and TDA, and was a pentablock copolymer having a block structure of (A)-(B)-(A)-(B)-(A) (polymer block (A)/polymer block (B)/polymer block (A)/polymer block (B)/polymer block (A)). The composition ratio of polymer block (A) to polymer block (B) calculated from the polymerization rate was (A)/(B) ≈ 15/85 (wt %).

[Synthesis Examples 49 to 77 and Comparative Synthesis Examples 7 to 9] Preparation of pentablock copolymers c-2 to c-30 and cc-1 to cc-3 Pentablock copolymers c-2 to c-30 and cc-1 to cc-3 were obtained by the same procedure as in Synthesis Example 48, except that the raw materials used were as shown in Tables 5 and 6. The molecular weights of the polymers were measured and shown in Tables 5 and 6. The composition ratios of polymer block (A) and polymer block (B) were calculated and shown in Tables 5 and 6.

<Post-treatment process of the pentablock copolymer>
[Production Example 1] Production of triblock copolymer d-1 A solution containing block copolymer c-1 (100.0 parts) obtained in Synthesis Example 48 was thoroughly degassed by nitrogen bubbling, and then n-propylamine (0.36 parts) was charged, and the decomposition reaction of the thiocarbonyl group was initiated in a thermostatic bath at 40° C. After 5 hours, the reaction was stopped by cooling to room temperature, and a solution containing block copolymer d-1 was obtained.
The solution containing the block copolymer d-1 was reduced in pressure to 20 kPa, and volatile components (unreacted monomers, solvent, etc.) were continuously distilled off using a thin-film evaporator maintained at 120° C., and the block copolymer d-1, which was a non-volatile component, was recovered.
Block copolymer d-1 is a triblock copolymer (polymer block (A)/polymer block (B)/polymer block (A)) having a block structure of (A)-(B)-(A) including a polymer block (A) consisting of BA, EA, TDA, and DMS, and a polymer block (B) consisting of BA, EA, and TDA, and is a Michael adduct of a thiol formed by decomposition of a thiocarbonylthio group of block copolymer c-1 with an amine and a residual acrylate compound contained in block copolymer c-1. It was confirmed from ¹ H-NMR measurement that the peak (4.8 ppm) of hydrogen bonded to the carbon adjacent to the thiocarbonylthio group, which was observed in block copolymer c-1, disappeared in block copolymer d-1, and peaks (3.3 ppm, 2.9 ppm) originating from a Michael adduct with a residual acrylate compound (terminal molecular structure represented by the following general formula (3)) appeared.
The molecular weight of the block copolymer d-1 was Mn 41,600, Mw 71,400, and Mw/Mn = 1.72. The polymer composition calculated from the monomer charge ratio and the reaction rate of each monomer measured by gas chromatography (GC) was BA unit: 73.4 mass%, TDA unit: 19.5 mass%, EA unit: 4.9 mass%, and DMS unit: 2.2 mass%. The average number of crosslinkable silyl groups per molecule was calculated to be 4.0. The E-type viscosity of the block copolymer d-1 was 198 Pa·s.
Furthermore, a dumbbell for a tensile test (JIS K 6251 No. 2 type) was prepared using the block copolymer d-1, and the recovery rate and tensile properties were measured. The recovery rate was 84%, the elongation at break (EI) was 339%, the breaking strength (Ts) was 0.25 MPa, and the strength at 50% elongation (M50) was 0.06 MPa.

[Production Examples 2 to 30 and Comparative Production Examples 1 to 3]
Block copolymers d-2 to d-30 and cd-1 to cd-3 were obtained by the same procedure as in Production Example 1, except that the raw materials were used as shown in Tables 7 and 8 and the desolvation temperature was appropriately adjusted. The molecular weight, polymer composition, average number of crosslinkable silyl groups per molecule, viscosity, recovery rate, and tensile properties of each polymer were measured and are shown in Tables 7 and 8.

Comparative Production Example 4: Production of telechelic polymer Copper (I) bromide (0.25 parts), pentamethyldiethylenetriamine (1.00 g), BA (302.4 g), TDA (80.4 g), EA (20.1 g) and anisole (247 g) were charged into a 1 L flask equipped with a stirrer and a thermometer, and the mixture was thoroughly degassed by nitrogen bubbling. Ethylene bis (2-bromoisobutyrate) (1.37 g) was added, and polymerization was started in a thermostatic bath at 80°C. Six hours after the start of polymerization, the mixture was heated and stirred under reduced pressure at 80°C to remove volatile matters. Acetonitrile (200 g), 1,7-octadiene (15.4 g), and pentamethyldiethylenetriamine (1.21 g) were added thereto, and stirring was continued for 8 hours. The mixture was heated and stirred under reduced pressure at 80°C to remove volatile matters, and a polymer-containing concentrate (1) was obtained.
Toluene was added to the concentrate (1) to dissolve the polymer, and then diatomaceous earth was added as a filter aid and aluminum silicate and hydrotalcite as adsorbents, and the mixture was heated and stirred in an oxygen-nitrogen mixed gas atmosphere (oxygen concentration 6%) at an internal temperature of 100° C. The solid content in the mixture was removed by filtration, and the filtrate was heated and stirred under reduced pressure at an internal temperature of 100° C. to remove volatile matters, thereby obtaining a polymer-containing concentrate (2).
Furthermore, 3 parts by mass of aluminum silicate as an adsorbent, 3 parts by mass of hydrotalcite, and 0.5 parts by mass of Irganox 1010 (manufactured by BASF) as an antioxidant were added to 100 parts by mass of the concentrate (2), and the mixture was heated and stirred under reduced pressure (reduced pressure of 10 Torr or less, average temperature of about 175° C.) to obtain a treatment liquid (1).
Next, 3 parts by mass of aluminum silicate as an adsorbent, 3 parts by mass of hydrotalcite, and 0.5 parts by mass of Irganox 1010 (manufactured by BASF) as an antioxidant were added to 100 parts by mass of the treatment liquid (1), and the mixture was heated and stirred in an oxygen-nitrogen mixed gas atmosphere (oxygen concentration 6%) at an internal temperature of 150° C. Subsequently, toluene was added, and the solid content in the mixture was removed by filtration, and the filtrate was heated and stirred under reduced pressure at an internal temperature of 60° C. to remove volatile matters, thereby obtaining a polymer having an alkenyl group.
The polymer having an alkenyl group, dimethoxymethylsilane (2.97 g), methyl orthoformate (1.49 g), and a platinum catalyst [a xylene solution of bis(1,3-divinyl-1,1,3,3-tetramethyldisiloxane) platinum complex catalyst: hereinafter referred to as platinum catalyst] (10 mg of platinum per kg of polymer) were mixed and stirred under a nitrogen atmosphere at 100° C. to obtain a reaction mixture.
The disappearance of the alkenyl groups was confirmed by ¹ H-NMR analysis, and the reaction mixture was concentrated under reduced pressure at an internal temperature of 60° C. to obtain a polymer (referred to as polymer cd-4) which was poly(n-butyl acrylate) having dimethoxysilyl groups at its terminals. The molecular weight of the obtained polymer cd-4 was measured to be Mn 42,000, Mw 54,300, and Mw/Mn 1.29. The average number of crosslinkable silyl groups introduced per molecule of polymer cd-4 was calculated to be 2.0 by ¹ H-NMR analysis. The E-type viscosity of polymer cd-4 was 205 Pa·s.
Furthermore, a dumbbell for a tensile test (JIS K 6251 No. 2 type) was prepared using polymer cd-4, and the recovery rate and tensile properties were measured. The recovery rate was 58%, the breaking strength (Ts) was 0.30 MPa, the strength at 50% elongation (M50) was 0.09 MPa, and the breaking elongation (El) was 353%.

<Production and evaluation of curable resin composition>
<Production of Curable Resin Composition>
[Example 1]
As the vinyl polymer base resin, the block copolymer d-1 obtained in Production Example 1 was used, and each component was blended according to the blending ratio shown in Table 9 below, to prepare a curable resin composition according to a conventional method.

Details of the compounds in Table 9 are as follows:
Polyoxyalkylene polymer: Modified silicone Exestar ES-S4530 (manufactured by AGC)
UP-1020: Acrylic plasticizer, ARUFON (registered trademark) UP-1020 (manufactured by Toagosei Co., Ltd.)
Light calcium carbonate: Viscolite-EL20 (manufactured by Shiraishi Calcium Co., Ltd.)
・Heavy calcium carbonate: Super SS (manufactured by Maruo Calcium Co., Ltd.)
R-820: Titanium oxide R-820 (manufactured by Ishihara Sangyo Kaisha)
B75: Anti-aging agent, Tinuvin B75 (manufactured by Chiba Specialty Co., Ltd.)
SH6020: 3-(2-aminoethylamino)propyltrimethoxysilane, SH6
020 (Dow Corning Toray Co., Ltd.)
SZ6300: Vinyltrimethoxysilane, SZ6300 (manufactured by Dow Corning Toray Co., Ltd.)
U-220H: Tin catalyst (dibutyltin diacetylacetonate), Neostan U-220H (manufactured by Nitto Kasei Co., Ltd.)

[Examples 2 to 30, Comparative Examples 1 to 4]
Using the vinyl polymers obtained in Production Examples 2 to 30 and Comparative Production Examples 1 to 4, the same procedure as in Example 1 was carried out to prepare curable resin compositions.

<Evaluation>
The curable resin compositions prepared above were evaluated by the following methods. The evaluation results are shown in Tables 10, 11, and 12.

(Tensile properties)
Each curable resin composition was applied to a Teflon (registered trademark) sheet at room temperature (25°C) to a thickness of 2 mm, and cured for 5 days under conditions of 23°C and 50% RH (relative humidity), and then for 1 day in a saturated water vapor atmosphere at 50°C to prepare a cured sheet.
Dumbbells for tensile tests were prepared from the resulting cured sheets and measured using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation). The shape of the dumbbells for tensile tests was based on Type 3 of JIS K 6251, a Japanese Industrial Standard. Specifically, the strength at 50% elongation (M50, unit: MPa), breaking strength (Ts, unit: MPa), and breaking elongation (El ₁ , unit: %) were measured under conditions of a temperature of 23°C, humidity of 50%, and a tensile speed of 200 mm/min.

(heat resistance)
The above dumbbells for tensile testing were heated in a dryer at 100°C for 42 days, and then aged for one day under conditions of 23°C and 50% RH (relative humidity). A tensile test was then performed at a tensile speed of 200 mm/min using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation), the breaking elongation ( _El2 , unit: %) was measured, and the breaking elongation retention rate ( _El2 / _El1 x 100) was calculated. A higher breaking elongation retention rate and a higher breaking elongation value indicate better heat resistance.

(Recovery rate)
The above-mentioned tensile test dumbbell was stretched at a rate of 5 mm/min using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation) so that the gauge length (dumbbell No. 3: 20 mm) became 40 mm, and was maintained for 24 hours. Next, the tensile test dumbbell removed from the tensile tester was placed on a Teflon (registered trademark) sheet having a thickness of 2 mm, and the gauge length (L ₂ ) was measured after 1 hour. The measurement was performed in an environment of a temperature of 23° C. and a relative humidity of 50%. The recovery rate was calculated by the following formula when the test piece could be stretched under the above measurement conditions and the test piece removed from the tensile tester showed recovery behavior.
Restoration rate [%] = (L ₁ - _{L 2} )/(L ₁ - _{L 0} ) x 100
Where L ₀ : Gauge length before stretching [mm]
_L1 : Gauge length when stretched [mm]
_L2 : Gauge length [mm] 1 hour after removal from the tensile tester
Here, L ₀ =20 mm and L ₁ =40 mm.

(Workability)
Each curable resin composition was applied onto a substrate with a trowel, and the ease of application of the curable resin composition (liquid) was evaluated according to the following criteria.
⊚: The curable resin composition can be spread evenly when the temperature is 5°C.
◯: When the temperature of the curable resin composition was 5° C., the trowel became heavy and it was difficult to spread the composition, but when the temperature was 10° C. or higher, the composition could be spread smoothly.
Δ: When the temperature of the curable resin composition was 10° C., the trowel became heavy and it was difficult to spread the composition, but when the temperature was 23° C., the composition could be spread smoothly.
x: Even when the temperature of the curable resin composition was 23° C., the trowel was heavy and the composition could not be spread evenly.

(weather resistance)
Each curable resin composition was applied to a Teflon (registered trademark) sheet at room temperature (25°C) to a thickness of 2 mm, and cured for 5 days under conditions of 23°C and 50% RH (relative humidity), and then cured for 1 day in a saturated water vapor atmosphere at 50°C to prepare a cured sheet.
The obtained cured sheet was placed in a metaling weather meter (DAIPLA METAL WEATHER KU-R5NCI-A manufactured by Daipla Wintes) and subjected to an accelerated weather resistance test. The conditions were irradiation temperature of 63°C, 70% RH, and illuminance of 80 mW/ ^cm2 , and the test was performed with a 2-minute shower once every 2 hours.
After 600 hours, 900 hours, and 1200 hours, the weather resistance was evaluated by visually checking the surface condition for the presence or absence of cracks on the surface and the degree of wrinkles and sagging, and was judged based on the following criteria: ◯: No change in surface condition.
Δ: No cracks were observed, but wrinkles and loosening were observed.
×: Cracks were generated.

(Dynamic Weather Resistance)
The cured sheet prepared in the weather resistance evaluation above was cut into a 15 mm x 70 mm strip to prepare a test piece. The cut test piece was placed in a metaling weather meter (DAIPLA METAL WEATHER KU-R5NCI-A manufactured by Daipla Wintes) and subjected to an accelerated weather resistance test. The conditions were irradiation at 63°C, 70% RH, and illuminance of 80 mW/ ^cm2 , and the test was performed with a 2-minute shower once every 2 hours.
After 300 hours, the test piece was stretched at a speed of 5 mm/min under conditions of 23° C. and 50% RH using a tensile tester so that the distance between the gauge lines was 60 mm (at 100% elongation). Two gauge lines were marked in the center of the rectangular test piece so that the distance between the gauge lines was 30 mm.
The surface condition (between the gauge lines and the elongated portion) was visually inspected to determine whether or not cracks had occurred on the surface, and was judged according to the following criteria.
○: No change in surface condition.
△: Cracks are partially generated.
×: Cracks occur all over the surface.

As is clear from the results of Examples 1 to 30, the sealants containing vinyl polymers d-1 to d-30 had excellent weather resistance (particularly dynamic weather resistance). In addition, the curable resin compositions of Examples 6, 10, 11, 15, 16, and 19, which contained vinyl polymers containing relatively large amounts of (meth)acrylic acid alkyl esters with alkyl groups having 10 or more carbon atoms, also had excellent workability.

On the other hand, Comparative Examples 1 to 4, which used vinyl polymers cd-1 to cd-4, had poor weather resistance (especially dynamic weather resistance). Upon detailed examination, it is presumed that the vinyl polymers cd-1 and cd-2 used in Comparative Examples 1 and 2 had the entire amount of hydrolyzable silyl group-containing vinyl compound charged at the start of polymerization when synthesizing polymer block (A), and therefore crosslinkable silyl groups could not be introduced uniformly between the polymer molecules. For this reason, it is believed that a uniform crosslinked structure was not formed when the product was cured, resulting in reduced weather resistance.

The vinyl polymer cd-3 used in Comparative Example 3 had an average number of crosslinkable silyl groups of 1.5, and it is believed that the cured product made using this vinyl polymer cd-3 had a low crosslink density and insufficient weather resistance. The vinyl polymer cd-4 used in Comparative Example 4 is a telechelic polymer (having a crosslinkable silyl group at the polymer end), with one crosslinkable silyl group at each end. This telechelic polymer has a lower crosslink density than the vinyl polymers d-1 to d-30, and its recovery rate was insufficient, which is believed to have reduced its weather resistance (especially dynamic weather resistance).

From the above, the vinyl polymer of the present disclosure has excellent tensile properties (elongation at break and strength at break) and recovery properties, and also has good fluidity (low viscosity) and therefore excellent handling properties. Such vinyl polymers of the present disclosure can be widely applied in various fields such as coatings for automobile parts, electrical appliances, and medical-related products, packings, gaskets, hose materials, adhesive raw materials, construction and civil engineering materials, and daily necessities. In addition, the curable resin composition containing the vinyl polymer of the present disclosure exhibits high weather resistance (particularly dynamic weather resistance) and heat resistance. Therefore, the curable resin composition can be applied as an adhesive, sealant, paint, coating agent, molding material, rubber sheet, etc., and is particularly suitable for use as a sealant.

The present invention is not limited to the above-described embodiment, but includes various modifications and modifications within the scope of equivalents, without departing from the spirit of the present invention. Therefore, in light of the above teachings, various combinations and forms, as well as other combinations and forms that include only one element, more than one element, or less than one element, should be understood to fall within the scope and concept of the present invention.

Claims (16)

A vinyl polymer having a crosslinkable functional group,
The vinyl polymer has a recovery rate of 75% or more and a breaking elongation of 300 to 600% after curing. The vinyl polymer according to claim 1, in which the average number of crosslinkable functional groups per molecule is 1.8 or more. The vinyl polymer according to claim 1, which contains 0.1 to 50 mass% of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 10 or more carbon atoms in the ester portion, based on the total structural units constituting the vinyl polymer. The vinyl polymer according to claim 1, in which the proportion of structural units derived from (meth)acrylic acid alkyl esters having an alkyl group with 2 or less carbon atoms in the ester portion is 20 mass % or less of the total structural units constituting the vinyl polymer. The vinyl polymer contains structural units derived from an alkyl (meth)acrylate ester having an alkyl group having 10 or more carbon atoms in an ester moiety in an amount of 0.1 to 50% by mass based on the total amount of structural units constituting the vinyl polymer,
2. The vinyl polymer according to claim 1, wherein a ratio of structural units derived from an alkyl (meth)acrylate ester having an alkyl group having 2 or less carbon atoms in an ester moiety is 20 mass% or less based on all structural units constituting the vinyl polymer. The vinyl polymer according to claim 1, which is a block copolymer consisting of polymer block (A)/polymer block (B)/polymer block (A). The vinyl polymer according to claim 6, wherein the polymer block (A) has the crosslinkable functional group. The weight average molecular weight (Mw) is 30,000 to 100,000;
2. The vinyl polymer according to claim 1, having a molecular weight distribution (Mw/Mn) of 1.80 or less. The vinyl polymer according to any one of claims 1 to 8,
an oxyalkylene polymer having a crosslinkable silyl group;
A curable resin composition comprising: The curable resin composition according to claim 9, wherein the mass ratio of the vinyl polymer to the oxyalkylene polymer is 10/90 to 90/10 when expressed as vinyl polymer/oxyalkylene polymer. The curable resin composition according to claim 9, which is for use as a sealant, adhesive, pressure sensitive adhesive or paint. A method for producing the vinyl polymer according to any one of claims 1 to 8, comprising the steps of:
A polymerization step of polymerizing a vinyl monomer,
The vinyl monomer includes a vinyl monomer having a crosslinkable functional group,
The method for producing a vinyl polymer, wherein the polymerization step is carried out while continuously or intermittently supplying into a reactor at least a part of the total amount of the vinyl monomer having a crosslinkable functional group used for producing the vinyl polymer. The method for producing a vinyl polymer according to claim 12, wherein the vinyl polymer is produced by living radical polymerization. A method for producing a vinyl polymer having a crosslinkable functional group, comprising the steps of:
the vinyl polymer is a block copolymer consisting of polymer block (A)/polymer block (B)/polymer block (A), and the average number of the crosslinkable functional groups per molecule is 1.8 or more;
a first polymerization step of polymerizing a vinyl monomer in the presence of a living radical polymerization inhibitor and a polymerization initiator to obtain the polymer block (A);
a second polymerization step of polymerizing a vinyl monomer in the presence of the polymer block (A) obtained in the first polymerization step and a polymerization initiator to form the polymer block (B);
Including,
The vinyl monomer used in the first polymerization step includes a vinyl monomer having a crosslinkable functional group,
The method for producing a vinyl polymer, wherein in the first polymerization step, polymerization is carried out while continuously or intermittently supplying into a reactor at least a part of the total amount of the vinyl monomer having a crosslinkable functional group used for producing the polymer block (A). The method for producing a vinyl polymer according to claim 14, wherein the living radical polymerization inhibitor is a chain exchange transfer mechanism type polymerization inhibitor. The method for producing a vinyl polymer according to claim 14 or 15, wherein the ratio of the vinyl monomer having a crosslinkable functional group that is continuously or intermittently fed into the reactor is 10 to 100 mass % based on the total amount of the vinyl monomer having a crosslinkable functional group used in the production of the polymer block (A).