TWI849006B - Primer composition - Google Patents

Abstract

[Problem of the present invention] A primer composition is provided, which is difficult to penetrate into porous building materials even when applied to porous building materials, can exhibit high film-forming properties, and has strong film strength after application, so that the filler material can be well attached to the porous building materials, and the continuous application property is also excellent when used on the previously applied filler material. [Means for solving the problem] The primer composition contains: (A) a methyl methacrylate polymer having a weight average molecular weight of 60,000 or more and a methyl methacrylate ratio of 80% by weight or more in the resin; and (B) a methyl methacrylate polymer containing an alkoxysilyl group having a weight average molecular weight of less than 80% by weight of methyl methacrylate in the resin.

Description

Primer composition

The present invention relates to a primer composition.

In the past, in residential construction, before the construction of the caulking material on the surface of the exterior wall material, the primer was applied to the surface. By applying the primer to the surface of the exterior wall material, the adhesion between the adherend and the caulking material is improved, and the surface strength of the caulking material with fragile surface strength can be strengthened. In recent years, due to the requirements of extending the service life of the house and maintenance-free, the exterior wall materials and caulking materials with high durability have been developed. In line with this, the primer used in the building caulking material is also required to have high durability.

In addition, kiln-made or wooden exterior wall boards are often used as exterior wall materials for wooden houses. Since these exterior wall boards are porous, they are easily affected by moisture and the primer easily penetrates. Therefore, the film-forming property of the primer on the exterior wall material is reduced, and good adhesion durability, especially adhesion durability under wet conditions, is not necessarily obtained.

Therefore, a primer composition is known, which contains: (A) a saturated hydrocarbon polymer having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and having at least one silicon-containing group that can be crosslinked by forming a siloxane bond (for example, refer to Patent Document 1). The primer composition in Patent Document 1 can improve long-term adhesion. In addition, a primer composition is known, which contains: (A) an organic polysiloxane resin containing a hydroxyl group or an alkoxy group bonded to a silicon atom, (B) a silane compound containing an amino group, (C) an isobutylene polymer containing an alkoxysilyl group, (D) a tin (IV) compound as a catalyst, and (E) an organic solvent (for example, refer to Patent Document 2). The primer composition in Patent Document 2 has been proposed to be used for porous surfaces.

On the other hand, after the filler is applied to the construction part such as the surface to be bonded, there are cases where the construction part must be repaired due to the deterioration of the filler. In this case, after the existing filler, that is, the filler applied first, is removed, when the new filler (the filler applied later) is applied, there are cases where the filler applied earlier cannot be completely removed. In this case, the filler applied later has to be applied successively to the filler applied earlier. In the case of the successive application of the filler, the filler applied earlier and the filler applied later need to have good adhesion to each other, but the adhesion often fails to achieve the desired goal, and generally, a primer is also used in the subsequent application.

However, even when a primer is used for the joint application of the sealing materials, there are cases where the joint application of the sealing materials is poor or the joint application cannot be performed successively.

Therefore, a primer composition for subsequent application of a modified polysilicone-based caulking material is known, which contains a) a polyisocyanate having an isocyanurate ring, b) an epoxysilane compound, c) one or more silane compounds selected from the group consisting of an aminosilane compound having a structure represented by a specified formula, an aminosilane compound having a structure represented by a specified formula, and a ketiminesilane compound having a structure represented by a specified formula, and d) a film-forming resin, and b) the epoxysilane compound is a condensate of at least one epoxysilane represented by a specified formula, or a condensate of at least one epoxysilane represented by a specified formula and at least one alkoxysilane represented by a specified formula (for example, refer to Patent Document 3).

Furthermore, the primer composition is not only an auxiliary material for the filler, but is also required to reduce the penetration of water, alkali, etc. from the inside of the porous material to the filler contact surface, and reduce the migration of plasticizers, etc. from the adherend or the filler (for example, refer to non-patent document 1). [Prior art document] [Patent document]

[Patent Document 1] Japanese Patent Publication No. 11-343429 [Patent Document 2] Japanese Patent Publication No. 2000-86990 [Patent Document 3] Japanese Patent Publication No. 4802448 [Non-Patent Document]

[Non-patent document 1] Handbook of building sealants, Japan Sealing Materials Industry Association, 2017, 19

[Problems to be solved by the invention]

However, although the primer composition described in Patent Document 1 can improve adhesion to glass or metal, it cannot fully exert its effect on porous building materials. In addition, although the primer composition described in Patent Document 2 is considered to be applicable to porous surfaces, it does not have sufficient durability in practical use. That is, in the situation where the properties required of primers have been upgraded due to recent technological innovations, optimization of materials, simplification and/or shortening of manufacturing processes, etc., there is no primer composition in the past that can satisfy the adhesion (e.g., initial adhesion, water-resistant adhesion, and heat-resistant adhesion) to various adherends such as kiln-type exterior wall panels or aluminum coated panels at a high level, and further improvement of these properties is sought.

Furthermore, the primer composition for subsequent application described in Patent Document 3 only exhibits the property of subsequent application by aminosilane, and since the property of subsequent application to the previously applied filler (normal adhesion, water-resistant adhesion) is not satisfied at a high level, further improvement of these properties of the primer composition for subsequent application is sought. Furthermore, the primer composition is also required to achieve the property of reducing the penetration of water and alkali from the inside of the porous material to the filler contact surface, and reducing the migration of plasticizers from the adherend or the filler (hereinafter referred to as "barrier property" in this specification).

Therefore, the purpose of the present invention is to provide a primer composition which is difficult to penetrate into porous building materials even when applied to porous building materials, can exert a high degree of film-forming property, and has a strong film strength after application, so that the caulking material can be well adhered to the porous building materials. Furthermore, a primer composition is provided which has excellent follow-up application property when used on the caulking material applied previously. [Means for solving the problem]

In order to achieve the above-mentioned object, the present invention provides a primer composition, which comprises: (A) a methyl methacrylate polymer having a weight average molecular weight of 60,000 or more and a methyl methacrylate content of 80% by weight or more in the resin; and (B) a methyl methacrylate polymer containing an alkoxysilyl group and having a methyl methacrylate content of less than 80% by weight in the resin.

In addition, the primer composition may further include (C) an amino group-containing silane.

Furthermore, the primer composition may further include (D) an epoxy resin.

Furthermore, the above-mentioned primer composition may also contain (E) a silane-based crosslinking agent. [Effect of the invention]

If the primer composition according to the present invention can provide a primer composition, even if it is applied to porous building materials, the primer composition is difficult to penetrate into the porous building materials, can exert a high degree of film-forming property, and the film strength after application is strong, so that the filler material can be well adhered even to the porous building materials, and the continuous application property is also excellent when used on the previously applied filler material.

[Form used to implement the invention]

>Definition and meaning of numerical values and terms> The definitions and meanings of the terms used in this manual are as follows.

(Definition of room temperature) The "room temperature (normal temperature)" in this manual refers to a temperature of 23°C.

(Meaning of term: solid at room temperature) In this specification, the term "solid at room temperature" means that the target substance (e.g., a specified composition) is a crystalline substance, a partially crystalline substance, and/or a glassy amorphous substance, and has a softening point higher than 23°C (measured by the cosmic method) or a melting point. The melting point here is the maximum value of the curve measured during a heating operation by, for example, dynamic differential calorimetry (differential scanning calorimetry [DSC]), and is the temperature at which the target material changes from a solid state to a liquid state.

(Weight average molecular weight) In this specification, the weight average molecular weight can be measured, for example, using HLC-8220 (manufactured by TOSOH Co., Ltd.) and polystyrene as a standard substance under the following conditions.

Columns used: TSKgel SuperMultiporeHZ-M×2, TSKguardcolumn SuperMP(HZ)-M×1, TSKgel Super MultiporeHM-L×1 Solvent: THF Flow rate: 1.0ml/min Measurement temperature: 40℃

(Glass transition temperature) The glass transition temperature (hereinafter sometimes referred to as "Tg") can be easily estimated from the type and amount of monomer components using the following Fox equation.

1/Tg=W ₁ /Tg ₁ +W ₂ /Tg ₂ +･･･+W _n /Tg _n (Fox formula)

In the above Fox formula, Tg is the glass transition temperature (K) of, for example, an acrylic resin, W ₁ , W ₂ , ..., and W _n are the weight fractions of each monomer, and Tg ₁ , Tg ₂ , ..., and Tg _n are the glass transition temperatures of homopolymers of each monomer. In addition, the glass transition temperature of the homopolymer used in the above Fox formula can be a value described in the literature, for example, in the Acrylate Catalog (1997 edition) of Mitsubishi Rayon Co., Ltd. or in Kyozo Kitaoka, "New Polymer Library 7 Introduction to Synthetic Resins for Coatings", Polymer Publishing Society, p168-p169, etc.

>Overview of primer composition> The inventors of this case have conducted various studies from the perspective of improving the various properties required of primer compositions. For example, although it is known that the use of aminosilanes can improve compatibility with modified polysilicone-based caulking materials and improve the continuous application of the caulking materials, in the prior art, acrylic components are used as film-forming resins (for example, Japanese Patent No. 4802448), and no prior art recognizes the improvement of adhesion due to acrylic components. The inventors of this case discovered the adhesion of acrylic components in primer compositions and studied compositions that maximize this property. As a result, it was found that by using a specified acrylic polymer and a silicone-containing polymer, a primer composition can be obtained that is difficult to penetrate into porous building materials, exhibits a high degree of film-forming property, has a strong film strength after coating, allows the caulking material to adhere well even to porous building materials, and has excellent subsequent application properties.

That is, the primer composition of the present invention is a composition containing (A) a methyl methacrylate polymer (hereinafter referred to as component (A)) and (B) a methyl methacrylate polymer containing an alkoxysilyl group (hereinafter referred to as component (B)). In addition, the primer composition of the present invention may further contain (C) an amino group-containing silane (hereinafter referred to as component (C)), (D) an epoxy resin (hereinafter referred to as component (D)), (E) a silane crosslinking agent (hereinafter referred to as component (E)), and/or other additives.

> Details of primer composition> The primer composition of the present invention is composed of (A) a methyl methacrylate polymer with a specified weight average molecular weight and (B) a methyl methacrylate polymer containing an alkoxysilyl group with a specified weight average molecular weight. In addition, the primer composition of the present invention can also be prepared by adding component (C), component (D), component (E), and/or other additives to component (A) and component (B). Moreover, the primer composition of the present invention has moisture curing properties at room temperature.

>(A) Methyl methacrylate polymer> The (A) methyl methacrylate polymer of the present invention is preferably a resin in which the ratio of methyl methacrylate contained in the resin is 80% by weight or more and the weight average molecular weight Mw (the apparent weight average molecular weight converted to polymethyl methacrylate by GPC [gel permeation chromatography] method) is 60,000 or more.

By making the ratio of methyl methacrylate contained in the resin 80% by weight or more and the weight average molecular weight 60,000 or more, even when the primer composition of the present invention is applied to porous building materials, the primer composition becomes difficult to penetrate into the porous building materials. As a result, the primer composition of the present invention can exhibit high film-forming properties, the film strength after application becomes strong, and excellent adhesion is exhibited.

The resin may include: a homopolymer of methyl methacrylate, or a copolymer of methyl methacrylate and any one or more copolymerizable monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, acrylonitrile, acrylic acid, methacrylic acid, 2-hydroxyacrylate, maleic anhydride, styrene, or α-methylstyrene.

As the monomers capable of copolymerization, alkyl acrylates having an alkyl group with 1 to 4 carbon atoms, such as methyl acrylate, ethyl acrylate, and n-butyl acrylate, and (meth)acrylic acid are preferred, methyl acrylate, ethyl acrylate, and (meth)acrylic acid are more preferred, and methyl acrylate and (meth)acrylic acid are even more preferred. By copolymerizing methyl methacrylate with these monomers, the solubility of component (A) in the solvent increases, and the viscosity of the primer composition of the present invention becomes appropriate (thickening), making it difficult to penetrate into porous building materials. Therefore, the primer composition of the present invention can exhibit high film-forming properties, and the film strength after coating becomes stronger, and exhibits excellent adhesion.

Commercially available products of component (A) include, for example, Delpowder (registered trademark) 80N (manufactured by Asahi Kasei Industries, polymethyl methacrylate, methyl methacrylate/methyl acrylate = 97.5/2.5 weight ratio, weight average molecular weight 100,000, concentrated viscosity 0.54 dl/g, glass transition temperature 105°C), a copolymer with methyl acrylate, Dianal (registered trademark) BR-84 (manufactured by Mitsubishi Rayon Co., Ltd., polymethyl methacrylate, weight average molecular weight 100,000, glass transition temperature 105°C, acid value: 6.5 mgKOH/g), and the like.

The weight average molecular weight Mw of component (A) is preferably 60,000 or more, more preferably 70,000 or more, further preferably 80,000 or more, and particularly preferably 90,000 or more. In addition, the weight average molecular weight Mw of component (A) of the present invention is usually preferably 200,000 or less, more preferably 180,000 or less, further preferably 160,000 or less, and particularly preferably 140,000 or less. If the weight average molecular weight Mw of component (A) is 60,000 or more, the barrier property, adhesion durability, and adhesion to porous surfaces of the primer composition are increased; if the weight average molecular weight Mw is 200,000 or less, good adhesion durability, workability, and adhesion to porous surfaces of the primer composition can be obtained.

In addition, the proportion of methyl methacrylate contained in component (A) is preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 95% by weight or more. The glass transition temperature of component (A) is preferably 80° C. or more, more preferably 90° C. or more, and even more preferably 95° C. or more; preferably 140° C. or less, more preferably 120° C. or less, and even more preferably 110° C. or less.

For the primer composition, the addition amount of component (A) is preferably 1% or more, more preferably 2% or more, and even more preferably 3% or more; preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less. If the addition amount of the primer composition is greater than 20%, the viscosity during the coating operation becomes high and the workability is reduced. If the addition amount is less than 1%, when coating porous building materials, the primer composition may penetrate into the porous building materials and fail to exert a high film-forming property. In addition, this addition amount represents the ratio when the mass of the entire primer composition is taken as 100%.

>(B) Alkoxysilyl-containing methyl methacrylate polymers> (B) Alkoxysilyl-containing methyl methacrylate polymers are (meth)acrylate polymers having alkoxysilyl groups and containing methyl methacrylate, which is solid at room temperature, as an essential monomer.

The methyl methacrylate polymer containing an alkoxysilyl group (B) of the present invention is preferably a resin in which the proportion of methyl methacrylate contained in the resin is less than 80% by weight and the weight average molecular weight Mw (apparent weight average molecular weight in terms of polystyrene by GPC [gel permeation chromatography] method) is less than 60,000.

Due to component (B), the primer composition exhibits excellent adhesion to the cured product of the caulking material (the caulking material applied first), and achieves good continuous application. In addition, when component (B) is used together with component (C) described later, it exhibits even better adhesion and good continuous application to the cured product of the caulking material (the caulking material applied first). Furthermore, the alkoxysilyl group of component (B) and the alkoxysilyl group of component (C) described later exhibit excellent adhesion to the substrate (exterior wall board, etc.) by curing. Furthermore, the silyl group of component (B) and the silyl group of component (C) can improve the hot water-resistant adhesion to the substrate by crosslinking.

(Alkoxysilyl) The alkoxysilyl of component (B) is a group having an alkoxy group bonded to a silicon atom and capable of crosslinking by a silanol condensation reaction. Examples of the alkoxysilyl group include groups represented by the following general formula (1).

In the general formula (1), ^R1 represents an alkyl group having 1 to 20 carbon atoms, a substituted alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. When there are two or more ^R1 groups, they may be the same or different. X represents an alkoxysilyl group. When there are two or more X groups, they may be the same or different. a represents 0, 1, 2 or 3. In the alkoxysilyl group of the general formula (1), a is preferably 2 or 3. When a is 3, the curing speed is faster than when a is 2.

Specific examples of ^R1 include alkyl groups such as methyl and ethyl, substituted alkyl groups such as methoxymethyl, and cycloalkyl groups such as cyclohexyl. Among these, methyl is preferred, and substituted alkyl groups in which the α carbon is substituted with a polar group are preferred from the viewpoint of increasing the curing speed.

There is no particular limitation on the alkoxysilyl group represented by X, as long as it is a conventionally known alkoxysilyl group. Among alkoxy groups, groups with fewer carbon atoms have higher reactivity, such as in the order of methoxy>ethoxy>propoxy, and the more carbon atoms there are, the lower the reactivity becomes. Although it can be selected according to the purpose and use, methoxy and ethoxy are generally used. In the case of the alkoxysilyl group represented by the general formula (1), a is preferably 2 or more in consideration of hardenability.

Specifically, examples of the alkoxysilyl group include trialkoxysilyl groups (-Si(OR ² ) ₃ ) such as trimethoxysilyl and triethoxysilyl; and dialkoxysilyl groups (-SiR ¹ (OR ² ) ₂ ) such as methyldimethoxysilyl and methyldiethoxysilyl. Here, R ¹ is the same as described above, and R ² is an alkyl group such as methyl or ethyl. As the alkoxysilyl group, trimethoxysilyl and triethoxysilyl are preferred from the viewpoint of high reactivity, and trimethoxysilyl is more preferred. From the viewpoint of obtaining a hardened material having flexibility, methyldimethoxysilyl and methyldiethoxysilyl are preferred.

The alkoxysilyl group may be used alone or in combination of two or more. The alkoxysilyl group may be present in the main chain or the side chain, or both.

The number (average value) of the alkoxysilyl groups of the component (B) is preferably 0.3 or more, more preferably 0.5 or more, and even more preferably 1 or more per polymer molecule; preferably 5 or less, more preferably 3 or less, and even more preferably 2.5 or less. If the number of alkoxysilyl groups contained in the molecule is less than 0.3, the curing property becomes insufficient, and if it is too much, the mesh structure becomes too dense and good mechanical properties cannot be exhibited.

(Method for introducing alkoxysilyl groups) In the preparation of component (B), alkoxysilyl groups can be introduced into (meth)acrylate polymers by various well-known methods. For example, the following methods can be cited as examples of methods for introducing alkoxysilyl groups.

(1) Copolymerizing an unsaturated compound having an alkoxysilyl group. (2) Polymerizing using an initiator or chain transfer agent having an alkoxysilyl group. (3) Reacting a (meth)acrylate polymer having a functional group such as a hydroxyl group with a compound having another functional group such as an epoxysilane that can react with the functional group and an alkoxysilyl group.

Among these methods for introducing alkoxysilyl groups, the method (1) of copolymerizing an unsaturated compound having an alkoxysilyl group is preferred from the viewpoint of ease of introduction of the alkoxysilyl group. A method of combining the method (1) with the method (2) is also preferred. For example, by using methyl methacrylate, 2-ethylhexyl methacrylate, 3-methacryloyloxypropyltrimethoxysilane, titanocene dichloride as a metal catalyst, 3-propyltrimethoxysilane (acting as an initiator and a chain transfer agent through the action of titanocene dichloride), and a benzoquinone solution as a polymerization terminator, and using the synthesis method according to Synthesis Example 4 of WO2015-088021, a (meth)acrylic polymer containing trimethoxysilyl groups as a methyl methacrylate-based polymer containing alkoxysilyl groups can be obtained.

(Unsaturated compounds with alkoxysilyl groups) As unsaturated compounds with alkoxysilyl groups used for copolymerization, (meth) acrylate alkyl esters and vinyl silanes with alkoxysilyl groups are preferred. As related compounds, for example, 3-(meth) acryloxypropyl trimethoxysilane, 3-(meth) acryloxypropyl methyl dimethoxysilane, 3-(meth) acryloxypropyl triethoxysilane, 3-(meth) acryloxypropyl alkoxysilane, vinyl triethoxysilane, etc., vinyl alkoxysilane, etc., etc., can be listed. Among these, (meth) acrylate alkyl esters with substituted alkyl groups in which the carbon number of the alkyl group with alkoxysilyl groups is 10 or less, preferably 3 or less are preferred.

(Other monomers other than monomers having alkoxysilyl groups used in component (B)) As other monomers other than monomers having alkoxysilyl groups used in component (B) of the present invention, there can be listed: methyl methacrylate-based random copolymers having methyl methacrylate as an essential monomer component and having repeating units represented by general formula (2).

-CH ₂ C(R ³ )(COOR ⁴ )- (2)

In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents a alkyl group which may have a substituent. In addition, (meth)acrylate represents acrylate and/or methacrylate alkyl ester.

As monomers other than the monomer having an alkoxysilyl group and methyl methacrylate used in the synthesis of the polymer of the component (B) of the present invention, preferably, an alkyl (meth)acrylate is used, more preferably, an alkyl (meth)acrylate having an alkyl group with 1 to 30 carbon atoms, and particularly preferably, an alkyl (meth)acrylate having an alkyl group with 1 to 30 carbon atoms and having no substituent.

Examples of the alkyl (meth)acrylate compound include well-known compounds such as methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate.

Furthermore, from the viewpoint of exhibiting excellent adhesion to the cured filler (previously applied filler) and achieving good subsequent application properties, alkyl (meth)acrylates having an ester group with a carbon number of 8 or more, such as 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate, are preferred. From the viewpoint of imparting flexibility to component (B), alkyl (meth)acrylates having a glass transition temperature (Tg) of 0°C or less, such as n-butyl acrylate (Tg: -55°C), 2-ethylhexyl acrylate (Tg: -70°C), and lauryl acrylate (Tg: -3°C), are preferred. In addition, the glass transition temperature in this paragraph refers to the glass transition temperature of a homopolymer.

The alkyl group of the (meth)acrylate may have a substituent such as a hydroxyl group, an alkoxy group, a halogen atom, or an epoxy group. Examples of such compounds include (meth)acrylates having a hydroxyl group such as hydroxyethyl (meth)acrylate, (meth)acrylates having an alkoxy group such as methoxyethyl (meth)acrylate, (meth)acrylates having an epoxy group such as glycidyl (meth)acrylate, and (meth)acrylates having an amino group such as diethylaminoethyl (meth)acrylate. In addition, unsaturated compounds having a high molecular chain such as acrylates having a polystyrene chain (macromonomer or macromonomer) may be used.

Furthermore, the methyl methacrylate polymer containing an alkoxysilyl group of the component (B) may contain, in addition to the repeating units derived from the (meth)acrylate compound, repeating units derived from a compound copolymerizable with the (meth)acrylate compound. Examples of the compound copolymerizable with the (meth)acrylate compound include: acrylic acid such as (meth)acrylic acid; amide compounds such as (meth)acrylamide; vinyl ether compounds such as alkyl vinyl ether; and other acrylonitrile, styrene, α-methylstyrene, vinyl chloride, vinyl acetate, and the like.

(Usage ratio of monomers) The amount of methyl methacrylate in the polymer of component (B) is less than 80% by weight, preferably 20% by weight or more, more preferably 30% by weight or more, and even more preferably 40% by weight or more. In addition, the usage ratio of the compound copolymerizable with the (meth)acrylate compound in the polymer of component (B) is preferably 20% by weight or less, more preferably 10% by weight or less, and even more preferably 5% by weight or less. However, when a macromolecular monomer is used, the amount of the macromolecular monomer in the polymer of component (B) is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 3% by weight or less.

(Glass transition temperature) Component (B) has a glass transition temperature (Tg) of 0°C to 120°C. The glass transition temperature is preferably 0°C or higher, more preferably 20°C or higher, and even more preferably 40°C or higher. Also, it is preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower. If the glass transition temperature is less than 0°C, the bonding strength immediately after bonding tends to be poor. Also, if the glass transition temperature is greater than 120°C, the viscosity becomes high, and the application of the primer to the adherend tends to become difficult. The glass transition temperature can be easily estimated using the above-mentioned Fox formula.

The molecular weight of component (B) is preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 3,000 or more, in terms of weight average molecular weight (molecular weight measured by GPC method in terms of polystyrene conversion); preferably 20,000 or less, more preferably 10,000 or less, and even more preferably 6,000 or less. When the weight average molecular weight is less than 1,000, the initial adhesion after coating is low, and when it is greater than 20,000, the viscosity during coating becomes too high, and workability is reduced. In addition, the polymer of component (B) is preferably solid at room temperature, or has a Globe softening point of 80°C or more.

The amount of component (B) added to the primer composition is preferably 5% or more, more preferably 10% or more, and even more preferably 20% or more; preferably 60% or less, more preferably 50% or less, and even more preferably 40% or less. If the amount added is greater than 60%, the viscosity during coating becomes too high, and workability is reduced. If the amount added is less than 5%, good continuous application properties cannot be achieved. In addition, this amount added is a ratio when the mass of the entire primer composition is taken as 100%.

(Polymerization method of component (B)) As the polymerization method of component (B), free radical polymerization method can be used. For example, conventional solution polymerization method and block polymerization method using thermal polymerization initiators such as benzoyl peroxide and azobisisobutyronitrile can be used. In addition, a method of polymerization by irradiation with light or radiation using a photopolymerization initiator can also be used. In free radical copolymerization, in order to adjust the molecular weight, a chain transfer agent such as lauryl mercaptan and 3-propyltrimethoxysilane can also be used. In addition, free radical polymerization method using a thermal polymerization initiator can be used to easily obtain the polymer of component (B) of the present invention by related methods. In addition, other polymerization methods such as the living radical polymerization method described in Japanese Patent Publication No. 2000-086998 can also be used.

>(C) Silane containing an amino group> From the viewpoint of not only improving the adhesion to the substrate (attachment member), but also further improving the adhesion to the cured filler material (previously applied filler material) by using it in combination with component (B), and having excellent continuous application properties, the primer composition of the present invention preferably further contains (C) silane containing an amino group. As the amino group of the silane containing an amino group (C), a monovalent functional group obtained by removing hydrogen from a primary amine or a diamine and a ketimine group can be listed. Specifically, as the silane containing an amino group (C) of the present invention, aminosilane and ketimine-based silane can be listed. In addition, ketimine silane is a silane compound that generates a specific amine by reacting with water, and in the present invention, ketimine silane is also included in the component (C).

Examples of aminosilanes include monosilylaminosilanes such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(β-aminoethyl)-3-aminopropyltrimethoxysilane, N-(β-aminoethyl)-3-aminopropyltriethoxysilane, and N-(β-aminoethyl)-3-aminopropylmethyldiethoxysilane; and bissilylaminosilanes such as bis(trimethoxysilylpropyl)amine, bis(triethoxysilylpropyl)amine, bis(triethoxysilylpropyl)ethylenediamine, N-[2-(vinylbenzylamino)ethyl]-3-aminopropyltrimethoxysilane, and aminoethyl-aminopropyltrimethoxysilane.

Furthermore, aminosilanes include: aminosilane reactants such as reactants of the above-mentioned aminosilanes and epoxysilanes, reactants of aminosilanes and silanes having a (meth)acryloxy group, reactants of aminosilanes and epoxy resins (bisphenol A diepoxypropyl ether, phenylepoxypropyl ether, etc.), reactants of aminosilanes and polyacrylates; condensates formed by partially condensing the above-mentioned silanes (preferably aminosilane condensates formed by partially condensing the above-mentioned aminosilanes, aminosilane reactants, and mixtures of the reactants); and modified derivatives thereof.

Examples of the ketimine silane include N-(1,3-dimethylbutylene)-3-(trimethoxysilyl)-1-propylamine, N-(1,3-dimethylbutylene)-3-(triethoxysilyl)-1-propylamine, N-(1,3-dimethylbutylene)-3-(methyldimethoxysilyl)-1-propylamine, and N-(1,3-dimethylbutylene)-3-(methyldiethoxysilyl)-1-propylamine.

The blending amount of component (C) is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 parts by mass or more, relative to 100 parts by mass of the total amount of component (A) and component (B); preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less. In addition, the blending amount of component (B) refers to the blending amount of the solid component excluding the solvent component from component (B).

>(D) Epoxy resin> The primer composition of the present invention may further contain (D) epoxy resin. (D) Epoxy resin reacts with (C) silane containing an amino group to strengthen the mesh structure of the primer composition after curing, thereby improving adhesion, water-resistant adhesion, and adhesion durability under high temperature and high humidity conditions. In addition, the barrier properties are improved by the strong mesh structure, thereby preventing discoloration and deterioration of the joint and peripheral parts of the filler material of the adherend. In particular, (D) epoxy resin inhibits the migration of active compounds by reacting with compounds having reactive groups, and exhibits an excellent effect in preventing discoloration and deterioration caused by compounds having reactive groups for epoxy groups such as amine compounds.

(D) As the epoxy resin, various epoxy resins can be used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin or epoxy resins hydrogenated from these, glycidyl epoxy resin, glycidyl amine type epoxy resin, aliphatic epoxy resin, novolac type epoxy resin, urethane epoxy resin, Urethane modified epoxy resins with ester bonds, fluorinated epoxy resins, rubber modified epoxy resins (e.g., epoxy resins modified from any of polybutadiene, styrene-butadiene rubber (SBR), nitrile rubber (NBR), and CTBN), flame retardant epoxy resins such as glyoxypropyl ether of tetrabromobisphenol A, etc. These epoxy resins can be used alone or in combination of two or more.

Among these epoxy resins, from the viewpoint of balance among workability, curability, bonding strength, versatility of adherends, water resistance, durability, etc., bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin or epoxy resins hydrogenated therefrom are preferred, bisphenol A type epoxy resin and bisphenol F type epoxy resin are more preferred, and bisphenol A type epoxy resin is the most preferred.

The molecular weight of component (D) is not particularly limited, but the weight average molecular weight is preferably 300 or more, more preferably 350 or more, and preferably 1,000 or less, more preferably 600 or less. In terms of easy handling, it is preferred to use an epoxy resin (D) that is liquid at room temperature.

The molar ratio (EP group/active hydrogen derived from amine group) of the epoxy group and the amine group (primary amine or diamine and ketimine group) of the component (D) is preferably 0.4 or more, more preferably 0.6 or more, and even more preferably 0.8 or more; preferably 3.0 or less, more preferably 2.0 or less, and even more preferably 1.0 or less.

The blending amount of component (D) is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, relative to 100 parts by mass of the total amount of component (A) and component (B). In addition, the blending amount of component (B) refers to the blending amount of the solid component excluding the solvent component from component (B).

>(E) Silane-based crosslinking agent> The primer composition of the present invention may further contain (E) silane-based crosslinking agent. As (E) silane-based crosslinking agent, silane compounds having two or more alkoxysilyl groups other than component (C) can be listed. (E) Silane-based crosslinking agent strengthens the mesh structure obtained after curing of the primer composition, and has the effect of improving adhesion, water-resistant adhesion, and adhesion durability under high temperature and high humidity conditions. In addition, (E) silane-based crosslinking agent can also enhance the barrier properties of the primer composition by promoting crosslinking. Therefore, from the perspective of enhancing the purpose of crosslinking, the number of alkoxysilyl groups in component (E) is preferably 2 or more, and more preferably 3 or more.

As the component (E), silane isocyanate, carbasilatrane, silane reaction products, silane condensates, and the like can be used.

Examples of the isocyanurate silane include isocyanurate propyltris(trimethoxysilyl) etc. Examples of the carbon-doped nitrogen silane tricyclic include the reaction product of 1.0 mol of 3-aminopropyltrimethoxysilane and 2.0 mol of 3-glycidoxypropyltrimethoxysilane described in Japanese Patent No. 3831481.

Examples of silane reactants and silane condensates (however, compounds containing primary or secondary amine groups are excluded in this paragraph) include reactants of aminosilane and epoxysilane, reactants of aminosilane and isocyanatesilane, reactants of aminosilane and silane having a (meth)acryloxy group, reactants of aminosilane and epoxy resins (bisphenol A diepoxypropyl ether, phenyl glycidyl ether, etc.), Aminosilane reactants such as reactants of silane and polyisocyanate, reactants of aminosilane and polyacrylate, etc.; condensates formed by partially condensing the above silanes (preferably aminosilane condensates formed by partially condensing the above aminosilane, isocyanate silane, aminosilane reactants, and mixtures of the reactants); amino-modified silyl polymers, silylated amine polymers, etc. of the modified derivatives thereof.

When the component (E) is used, the blending amount of the silane-based crosslinking agent (E) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, and preferably 60 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 15 parts by mass or less, relative to 100 parts by mass of the total amount of the components (A) and (B). In addition, the blending amount of the component (B) refers to the blending amount of the solid component excluding the solvent component from the component (B).

>Other additives> The primer composition of the present invention may contain other additives as needed. Examples of such additives include: solvents, condensation reaction accelerators, dehydrating agents, silane-based bonding agents, polyisocyanate compounds, chlorinated polymers, polyurethane-based resins, pigments, dyes, anti-aging agents, antistatic agents, flame retardants, etc.

(Solvent) As solvents, there can be cited, for example, organic solvents such as aliphatic compounds (n-hexane, heptane, etc.), aromatic compounds (toluene, xylene, etc.), alcohols (methanol, ethanol, isopropanol, butanol, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, butyl thiocyanate, etc.), and light petroleum. The solvent can be one or more of these, and can be added to the primer composition of the present invention in an appropriate amount.

Among these solvents, methyl ethyl ketone and ethyl acetate are preferred from the viewpoint of better connection speed and workability. In addition, the above solvents are preferably used after being fully dried or dehydrated.

The content of the solvent is preferably 40% to 90% of the total mass of the primer composition of the present invention, and more preferably 50% to 80%. If the content of the solvent is within this range, good coating properties can be obtained. In addition, the content of the solvent in the primer composition of the present invention can be appropriately changed according to the use and purpose of the composition.

(Condensation reaction accelerator) As the condensation reaction accelerator of the alkoxysilyl group, a wide range of well-known hardening catalysts can be used, for example, a silanol condensation catalyst is preferably used. As the silanol condensation catalyst, for example, metal catalysts, tin catalysts, amine catalysts, etc. can be listed; as the amine catalyst, organic metal compounds, amines (especially tertiary amines), salts of tertiary amines and carboxylic acids, etc. can be listed.

Specifically, as the organic metal compound, for example, there can be listed: divalent organic tin compounds such as tin octylate; tetravalent organic tin compounds such as dibutyltin dilaurate, dibutyltin diacetate, dioctytin dilaurate, and the reaction product of dibutyltin oxide and phthalate; chelates of various metals such as dibutyltin bis(acetylacetonate), titanium tetrakis(acetylacetonate), aluminum tris(acetylacetonate), and bis(acetylacetonate); titanium esters such as tetrapropyl titanate, etc.

As amines, there can be mentioned, for example, primary and secondary amines such as octylamine; polyamines; N-methyl Cyclic amines such as cyclohexane, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), amine compounds such as aminophenol compounds such as 2,4,6-tris(dimethylaminomethyl)phenol, and their carboxylates, and reaction products of excess polyamines and epoxy compounds. These catalysts may be used alone or in combination of two or more.

Among these, tin catalysts and amine catalysts are preferred from the viewpoint of having a large catalytic ability in a trace amount, and tin catalysts are particularly preferred. Either or both of tin catalysts and amine catalysts can be used. As tin catalysts, either divalent or tetravalent catalysts can be used alone, or both can be used in combination. As amine catalysts, tertiary amines are preferably used.

When a condensation reaction accelerating catalyst is used, the amount of the condensation reaction accelerating catalyst blended is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, and preferably 10 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1 part by mass or less, based on 100 parts by mass of the total amount of component (A) and component (B).

(Dehydrating agent) As dehydrating agents, there can be listed: silane compounds such as vinyltrimethoxysilane, dimethoxydiphenylsilane, methyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane, and tetramethoxysilane; ester compounds such as trimethyl orthoformate and triethyl orthoformate. These dehydrating agents can be used alone or in combination of two or more. In addition, as dehydrating agents, silane compounds are preferred, and dimethoxydiphenylsilane and phenyltrimethoxysilane are more preferred.

When a dehydrating agent is used, the amount of the dehydrating agent blended is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, and preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass of the total amount of component (A) and component (B).

(Silane-based adhesives) From the perspective of improving the adhesion of hard-to-adhere painted surfaces, silane-based adhesives can be added to the primer composition of the present invention. Examples of silane-based adhesives include epoxy silane, acrylic silane, butyl silane, urea silane coupling agents, isocyanate silane, etc.

Examples of epoxysilanes include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane. Examples of acrylic silanes include 3-methacryloyloxypropyltrimethoxysilane. Examples of ethylsilanes include 3-ethyltrimethoxysilane. Examples of urea silane coupling agents include 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane. As the isocyanate silane, 3-isocyanatepropyltriethoxysilane can be mentioned.

From the viewpoint of adhesion, epoxysilane, acrylic silane-based silane, urea silane-based coupling agent, and isocyanate silane are preferred, and epoxysilane is more preferred.

When a silane bonding agent is used, the blending amount of the silane bonding agent is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 parts by mass or more, and preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, based on 100 parts by mass of the total amount of component (A) and component (B).

(Polyisocyanate compound) The primer composition of the present invention may further contain a polyisocyanate compound. There is no particular limitation on the polyisocyanate compound as long as it has two or more isocyanate groups in the molecule. The polyisocyanate compound can exhibit a high degree of film-forming property, and the film strength after coating becomes stronger, and excellent adhesion is exhibited. In addition, the isocyanate group hardens and exhibits excellent adhesion to the substrate (exterior wall board, etc.), and the isocyanate group can enhance the warm water resistance and heat resistance adhesion to the substrate by crosslinking.

Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), polymethylene polyphenyl isocyanate (polymethylene polyphenyl isocyanate) (polymeric MDI), aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), alicyclic polyisocyanates such as isophorone diisocyanate (IPDI), addition products of these polyisocyanates, such as those formed using trihydroxymethylpropane or glycol, such isocyanurate-modified polyisocyanates, alloformate-modified polyisocyanates, biuret-modified polyisocyanates, and the like. Such polyisocyanates may be used alone or in combination of two or more.

From the viewpoint of good film-forming property and better adhesion to the coating surface with poor adhesion, the polyisocyanate compound preferably has three or more isocyanate groups. As the polyisocyanate compound having three or more isocyanate groups, for example, polyisocyanate adducts obtained by reacting compounds such as thiophosphoric acid phenyl isocyanate and trihydroxymethyl propane (TMP) with the above-mentioned polyisocyanate compound, and adducts, biuret bodies, and isocyanurates of polyisocyanate compounds, etc., can also be listed. Hereinafter, such polyisocyanate compounds are referred to as "isocyanate adducts". These can be used alone or in combination of two or more.

Examples of such isocyanate adducts include HDI-TMP adducts obtained by reacting HDI with TMP, XDI-TMP adducts obtained by reacting XDI with TMP, TDI-TMP adducts obtained by reacting TDI with TMP, TMXDI-TMP adducts obtained by reacting TMXDI with TMP, HXDI-TMP adducts obtained by reacting HXDI with TMP, IPDI-TMP adducts obtained by reacting IPDI with TMP, biuret form of HDI, isocyanurate form of HDI, isocyanurate form of IPDI, isocyanurate form of TDI, etc. Among these, TDI-TMP adducts obtained by reacting TDI with TMP and isocyanurate modified products are preferred.

As the polyisocyanate compound having an isocyanurate ring, an isocyanurate modified product of a diisocyanate compound obtained by trimerizing a diisocyanate compound is preferred. As the diisocyanate compound, for example, the aromatic polyisocyanates exemplified above can be cited. Among these, the polyisocyanate compound having an isocyanurate ring obtained by reacting a mixture of TDI and HDI is preferred from the viewpoint that the initial adhesion and hot water-resistant adhesion to the difficult-to-adhere coating surface become better and sufficient adhesion can be obtained.

Examples of commercially available polyisocyanate compounds include thiophosphoric acid phenyl isocyanate (Desmodur RFE, manufactured by Bayer AG), a polyisocyanate compound having an isocyanurate ring obtained by reacting a mixture of HDI and TDI (Desmodur HL, manufactured by Bayer AG), and polymethylene polyphenyl isocyanate (Sumidur 44V-10, manufactured by Sumika Bayer Urethane Co., Ltd.).

(Chlorinated polymer) Chlorinated polymers can exhibit high film-forming properties, and the film strength after coating becomes stronger, and excellent adhesion is exhibited. Examples of chlorinated polymers include chlorides of isoprene-based synthetic rubbers, chlorinated polyethylene, chlorinated polypropylene, chlorinated polyethylene-propylene copolymers, chlorinated polybutadiene, chlorinated polystyrene, chlorinated polybutadiene-styrene copolymers, chlorosulfonated polyethylene, and chlorosulfonated polyethylene-vinyl acetate copolymers.

(Polyurethane resin) Polyurethane resins have high film-forming properties, and the film strength after coating becomes strong and has excellent adhesion. Polyurethane resins are compounds formed by copolymerizing monomers through urethane bonds formed by condensation of isocyanate groups and alcohol groups. As polyurethane resins, various polyurethane resins can be used within the range in which the effects of the present invention are exerted. As polyurethane resins, from the viewpoint of adhesion of the primer composition, those with a number average molecular weight of 3,000 to 60,000 are preferred. Polyurethane resins can be used alone or in combination of two or more.

As the polyurethane resin, commercially available products such as polyurethane resin (PANDEX (registered trademark) T-5205, number average molecular weight: 60,000, manufactured by DIC Corporation) and polyurethane resin (PANDEX (registered trademark) T-5201, number average molecular weight: 55,000, manufactured by DIC Corporation) can be used.

(Pigment) As the pigment, one or both of inorganic pigments and organic pigments can be listed. For example, inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, hematite, zinc barium white, lead, cadmium, iron, cobalt, aluminum, hydrochloride, and sulfate; organic pigments such as azo pigments and copper phthalocyanine pigments can be used.

(Dye) As dye, conventionally known dyes can be used. For example, black dye, yellow dye, red dye, blue dye, brown dye, etc.

(Anti-aging agent) As anti-aging agents, for example, hindered phenol compounds, hindered amine compounds, benzotriazole compounds, etc. can be cited.

(Antistatic agent) As antistatic agents, for example, hydrophilic compounds such as quaternary ammonium salts, polyglycols, and ethylene oxide derivatives can be cited.

(Flame retardant) As flame retardants, for example, chloroalkyl phosphates, dimethyl methylphosphonate, bromine-phosphorus compounds, ammonium polyphosphate, bromine neopentane polyether, brominated polyether, etc. can be cited.

>Preparation method of primer composition> The preparation method of the primer composition of the present invention is not particularly limited, and can be manufactured using, for example, a mixer that can uniformly mix liquids. For example, by weighing a specified amount of materials constituting the primer composition (component (A), component (B), component (C), component (D), component (E), and/or other additives), the weighed materials are mixed using a mixer with a single-axis or double-axis stirring shaft, or a tank with a pulsating pump at the bottom. In particular, it is preferred to use a device equipped with a jacket that can variably adjust the temperature of the material.

>Method for applying primer composition> There is no particular limitation on the method for applying the primer composition of the present invention to the adherend. For example, the following application method is preferred. First, use a brush, pen, etc. to remove the liquid until the liquid does not fall, and then apply the primer composition of the present invention evenly to the adherend surface with a coating amount of 50 to 400 ml/ ^m2 . After 30 minutes to 8 hours after application, apply the caulking material. In addition, it is preferred to avoid construction on rainy days and use in an environment where water droplets remain on the surface of the adherend. It is preferred to apply the primer composition under conditions of 5°C to 35°C.

>Applications> The primer composition of the present invention can be suitably used in primer compositions, caulking materials, adhesives, etc. for construction, civil engineering, concrete, wood, metal, glass, plastic, etc. In addition, the primer composition of the present invention can be suitably used in caulking materials because of its excellent continuous application property to the cured caulking material.

Furthermore, the primer composition of the present invention can also be appropriately used as a primer for poorly adherent painted components. Examples of poorly adherent painted components that can use the primer composition of the present invention include acrylic electrodeposition painted components, fluorine baking paint components, and anodic oxidation painted components. Furthermore, the primer composition of the present invention can also be used for components other than poorly adherent painted components.

>Effects of Implementation Forms> The primer composition of the present invention comprises component (A) and component (B) containing alkoxysilyl. Component (A) and/or component (B) have a specified weight average molecular weight and/or a specified ratio of methyl methacrylate. Therefore, even when applied to or in contact with a porous building material (for example, the surface of the side of an exterior wall sheet, etc.) as a target, the primer composition has an effect of being difficult to penetrate into the porous building material. Therefore, the primer composition of the present invention can exhibit a high degree of film-forming property and can enhance the film strength after application. In addition, the primer composition of the present invention can be easily applied by brushing, etc., and can also exhibit a high degree of workability. Therefore, the primer composition of the present invention can be applied to exterior wall materials such as kiln-based or wooden exterior wall panels, especially exterior wall materials coated with sealers or paints.

Furthermore, the primer composition of the present invention can inhibit the migration of plasticizers and the like from the adherend or the filler material due to its high barrier properties, and can also exhibit high adhesion durability over a long period of time. Moreover, the primer composition of the present invention can exhibit high adhesion even on a wet surface. [Example]

The following examples are used to further explain the present invention. In addition, these examples are illustrative only and should not be construed in a limiting sense.

(Synthesis Example 1: Methacrylic Resin Containing Alkoxysilyl Groups) As a methacrylic resin containing alkoxysilyl groups, a (meth)acrylic polymer containing trimethoxysilyl groups was synthesized. Specifically, 70.00 g of methyl methacrylate, 30.00 g of 2-ethylhexyl methacrylate, 12.00 g of 3-methacryloyloxypropyltrimethoxysilane, 0.10 g of titanium cyclopentadienyl chloride as a metal catalyst, 8.60 g of 3-butyltrimethoxysilane, and 20.00 g of benzoquinone solution (95% THF solution) as a polymerization terminator were used to obtain a (meth)acrylic polymer containing trimethoxysilyl groups according to the method of Synthesis Example 4 of WO2015-088021.

The solid content was determined by heating the ethyl acetate solution of the obtained reaction product at 105°C, and the result was 70.5%. The molecular weight of the obtained polymer measured by gel permeation chromatography (GPC) in terms of polystyrene was 4,000 in weight average molecular weight (Mw), and the molecular weight distribution (Mw/Mn) was 2.4. Furthermore, by ¹ H-NMR measurement (using NMR400 manufactured by Shimadzu Corporation, measured in CDCl ₃ solvent), it was confirmed that the trimethoxysilyl group contained was 2 per molecule. The glass transition temperature was 61°C.

(Examples, Comparative Examples) For Examples 1 to 12 and Comparative Examples 1 to 3, component (A), component (A'), component (B), component (C), component (D), component (E), and other additives were mixed in the blending ratios shown in Table 1, and the mixture was stirred and mixed. Thus, primer compositions of Examples and Comparative Examples were obtained. Then, the primer compositions of Examples 1 to 12 and Comparative Examples 1 to 3 were evaluated as follows. The results are shown in Table 1. In addition, the unit of the blending amount of each blending substance in Table 1 is "g".

[Table 1] Element Material Embodiment Comparison Example 1 2 3 4 5 6 7 8 9 10 1 2 3 A Methyl methacrylate polymer Delpowder 80NS 10 10 10 10 20 - 10 10 10 10 - - 10 Dianal BR84 - - - - - 10 - - - - - - - A' ARUFON UH-2170 - - - - - - - - - - - 10 - B Alkoxysilane-containing methacrylate resin The polymer obtained in Synthesis Example 1 100 100 100 100 100 100 100 60 60 60 100 100 - C Amine-containing silane KBM903 - 0.9 0.9 0.9 0.9 0.9 - - - - 0.9 0.9 0.9 Dynasylan1124 - 0.8 0.8 0.8 0.8 0.8 - - - - 0.8 0.8 0.8 Ketimine coupling agent - - - - - - 1.3 1.3 1.3 1.3 - - - (D) Epoxy jER828 - - - - - - 1.0 3.0 - - - - - EP1001 - - - - - - - - 2.3 - - - - (E) Silane crosslinking agent X-12-965 - - - - - - - - - 5.0 - - - (-) Dehydrating agent KBM202SS 2.0 - 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 - - 2.0 A-1630 - - - - - - - - - - 2.0 2.0 - (-) Solvent Dehydrated ethyl acetate 100 100 100 100 100 100 100 100 100 100 100 100 100 (-) Catalyst U-360 0.2 0.2 - 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Reviews Workability Brush-on ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Film forming properties ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ × × × Continue to apply continuity POS seal LM ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ × POS seal LM super weather resistant ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ × Barrier properties Chlorinated Polypropylene ○ ○ ○ ○ ◎ ○ ◎ ◎ ◎ ◎ × × △ Stretch Adhesion (Normal/MOEN M) 50% modulus (MPa) 0.09 0.08 0.09 0.08 0.07 0.07 0.07 0.07 0.07 0.08 0.07 0.07 0.08 Tmax(MPa) 0.34 0.32 0.33 0.37 0.34 0.36 0.35 0.36 0.35 0.35 0.32 0.34 0.30 Emax(%) 573 562 573 628 575 582 614 584 561 580 556 590 522 Tensile Adhesion (80℃2w/MOEN M) 50% modulus (MPa) 0.10 0.09 0.10 0.10 0.09 0.10 0.09 0.09 0.09 0.09 0.09 0.09 0.10 Tmax(MPa) 0.46 0.44 0.45 0.44 0.46 0.46 0.44 0.50 0.45 0.45 0.50 0.47 0.33 Emax(%) 563 586 592 610 604 585 605 637 586 616 614 614 429 Stretch adhesion (60℃ warm water 2w/ MOEN M) 50% modulus (MPa) 0.09 0.08 0.09 0.09 0.08 0.09 0.08 0.08 0.08 0.08 0.09 0.08 0.09 Tmax(MPa) 0.27 0.24 0.29 0.23 0.32 0.34 0.27 0.29 0.30 0.24 0.18 0.19 0.19 Emax(%) 489 506 505 489 536 628 576 591 567 454 312 375 272

The details of the materials shown in Table 1 are as follows. In addition, the blending amount of component (B) in Table 1 includes the amount of the solvent. (Component (A)) ・Delpowder (registered trademark) 80NS: Asahi Kasei Industries, polymethyl methacrylate, MMA/MA = 97.5/2.5 weight ratio, weight average molecular weight: 100,000, concentrated viscosity: 0.54 dl/g, glass transition temperature (Tg): 105°C ・Dianal BR84: Mitsubishi Rayon Co., Ltd., polymethyl methacrylate, weight average molecular weight: 100,000, glass transition temperature (Tg): 105°C, acid value: 6.5 mgKOH/g

(Component (A’)) ・ARUFON (registered trademark) UH-2170: Made by Toagosei Co., Ltd., styrene, acrylic acid, weight average molecular weight: 14,000, OH value: 88 mgKOH/g, glass transition temperature (Tg): 60°C/DSC

(Component (C)) ・KBM903: Shin-Etsu Chemical Co., Ltd., amine coupling agent, weight average molecular weight: 179, 3-aminopropyltrimethoxysilane ・Dynasylan1124: Evonik Co., Ltd., weight average molecular weight: 343, amine coupling agent, bis(3-trimethoxysilylpropyl)amine ・Ketimine coupling agent: N-(1,3-dimethylbutylene)-3-(trimethoxysilyl)-1-propylamine, weight average molecular weight: 261

(Component (D)) ・jER828: Mitsubishi Chemical, bisphenol A type epoxy resin, liquid, weight average molecular weight: 370, d = 1.17, epoxy equivalent: 184 to 194 ・EP1001: Mitsubishi Chemical, epoxy resin, solid, weight average molecular weight: 900, d = 1.19, softening point: 97°C, epoxy equivalent: 450 to 500

(Component (E)) ・X-12-965: Shin-Etsu Chemical Co., Ltd., isocyanurate coupling agent, weight average molecular weight: 616, number of Si groups: 3, isocyanurate (trimethoxysilylpropyl)

(Dehydrating agent) ・KBM202SS: Made by Shin-Etsu Chemical Co., Ltd., benzene-based coupling agent, diphenyldimethoxysilane ・A-1630: Made by Momentive Co., Ltd., coupling agent, trimethoxymethylsilane

(Catalyst) ・U-360: Made by Nitto Chemical Co., Ltd., silanol catalyst, dibutyltin octyl silanol acetate

(Evaluation method: workability) In the evaluation of workability, the brushability and film-forming properties of the primer composition were evaluated. Specifically, regarding brushability, the primer composition of Example 1 was first applied to the side of an exterior wall sheet (MOEN SIDING M, manufactured by Nichiha Co., Ltd.) with a brush. Similarly, as a comparison object, a comparison primer composition (MP3000, manufactured by CEMEDINE Co., Ltd.) was applied to the side of an exterior wall sheet (MOEN SIDING M, manufactured by Nichiha Co., Ltd.) with a brush.

Then, regarding brush-applicability, the ease of application of the primer composition during application was evaluated by comparing the primer composition of Example 1 with the comparative primer composition. The evaluation criteria were as follows.

"○": Ease of application is equal to or greater than that of MP3000. "×": Harder to apply than MP3000.

In addition, regarding the film-forming property, all the primer composition applied on the side surface does not penetrate into the side surface, and the state of the film formed by the primer composition on the side surface is evaluated by visual inspection. The evaluation criteria are as follows.

"○": Uniform film formation was observed. "×": Sparse (partially penetrated, disappeared) film formation was observed.

The same evaluation was performed on other examples and comparative examples. The evaluation results are shown in Table 1.

(Evaluation method: Adhesion of continuous application) The adhesion of continuous application was evaluated as follows. First, a modified polysilicone caulking material ("POS seal LM" manufactured by CEMEDINE) as the adherend to be applied first was cured for 7 days in an environment of 23°C 50%RH. Next, the primer composition of Example 1 was applied to the surface of the cured caulking material (adhesion), and after being placed in an environment of 23°C 50%RH for 30 minutes, a modified polysilicone caulking material ("POS seal LM Super Weathering" manufactured by CEMEDINE) for continuous application was applied thereon in beads as a test piece. After the test piece was cured for 3 days at 23℃50%RH and then for 4 days at 50℃40%RH, a portion of the interface (i.e., the interface between the adherend and the modified polysilicone-based caulking material) was cut with a knife and the cut portion was peeled off by hand. The peeled state was then visually observed to evaluate the damage state. The evaluation results are shown in the "Continuous Application Adhesion: POS seal LM" column of Table 1. In addition, the evaluation criteria are as follows.

"○": Cohesive failure of the previously applied and/or subsequently applied filler material. "×": The cured product of the primer composition fails at the interface with the previously applied filler material.

In addition, the same procedure as above was followed to evaluate the subsequent application adhesion, except that a modified polysilicone-based caulking material ("POS seal LM Super Weathering" manufactured by CEMEDINE) as the adherend to be applied first was cured for 7 days in an environment of 23°C and 50%RH. The evaluation results are shown in the "Continuous Application Adhesion: POS seal LM Super Weathering" column of Table 1. The other embodiments and comparative examples were also evaluated in the same manner. The evaluation results are shown in Table 1.

(Evaluation method: barrier property) The barrier property was evaluated as follows. A chlorinated polypropylene coating agent (20% ethyl acetate solution of SUPERCHLON 814HS (manufactured by Nippon Paper Industries)) was applied to the surface of a stainless steel plate and left in an environment at 23°C for 24 hours to obtain a stainless steel plate coated with chlorinated polypropylene. The primer of Example 1 (0.02 g/ ^cm2 ) was applied on the coating of the obtained stainless steel plate and dried in an environment at 23°C for 1 hour.

The filler material (POS seal LM super weatherproof) was applied in beads on the dried primer and cured for 3 days at 23℃50%RH and 4 days at 50℃40%RH. After further heating at 70℃ for 3 days, the filler material was cut along the interface with a cutter and the coating part in contact with the filler material was observed to confirm the color change. The evaluation criteria are as follows.

"◎": No change "○": Almost no change "△": Some change "×": Change (color change)

The other examples and comparative examples were evaluated in the same manner. The evaluation results are shown in Table 1.

(Evaluation method: tensile adhesion) The test method and characteristic determination method of tensile adhesion are based on the standard "JTC S-0001 Kiln industry exterior wall board joint filling material (2004)" of the NPO Corporation Housing Exterior Decoration Technology Center, and the I-shaped test body described in 5.1.6 of the same specification is made and implemented. First, the exterior wall board (MOEN SIDING M, manufactured by Nichiha Co., Ltd.) is cut into a size of 50mm long and 50mm wide to make the first exterior wall board and the second exterior wall board. Then, the first and second outer wall panels obtained by cutting are fixed so that the sides are facing each other at a distance of 10 mm in the longitudinal direction, that is, the distance between the sides of the first and second outer wall panels is 10 mm. Then, a back-up material made of expanded polystyrene with a length of 50 mm, a width of 10 mm, and a thickness of 6 mm is placed under the gap between the side of the first and second outer wall panels, and the surfaces of the first and second outer wall panels are covered with masking tape. Then, the primer composition of Example 1 was applied to the area in contact with the caulking material (i.e., the side surface of the first exterior wall board and the side surface of the second exterior wall board), and the caulking material (POS seal LM super weatherproof, manufactured by CEMEDINE Co., Ltd.) was filled in the gap (joint) with a thickness of 8 mm at intervals of 10 mm, and then the masking tape was removed to prepare a test sample.

Then, in order to evaluate the normal adhesion, the test sample was cured in an environment of 23℃50%RH for 1 week, and then cured in an environment of 30℃ for 1 week, and then a tensile adhesion test was performed in an environment of 23℃ at a tensile speed of 50mm/min. ("Tensile Adhesion (Normal/MOEN M)" in Table 1). In addition, in order to evaluate the heat-resistant adhesion, another test sample was cured in an environment of 23℃50%RH for 1 week, and then cured in an environment of 30℃ for 1 week, and then cured in an environment of 80℃ for 2 weeks. Then, after each curing period, a tensile adhesion test was performed at a tensile speed of 50 mm/min in an environment of 23°C ("Stretch Adhesion (80°C 2w/MOEN M)" in Table 1). Furthermore, in order to evaluate water-resistant adhesion, another test sample was cured in an environment of 23°C 50% RH for 1 week, further cured in an environment of 30°C for 1 week, and then immersed in warm water at 60°C for 2 weeks. Then, after each curing period, a tensile adhesion test was performed at a tensile speed of 50 mm/min in an environment of 23°C ("Stretch Adhesion (60°C Warm Water 2w/MOEN M)" in Table 1). In the tensile adhesion test, the load (MPa) when the elongation is 50%, the maximum load (T _max (MPa)), and the elongation at the maximum load (E _max (%)) are measured. In addition, the "50% modulus" in Table 1 is the load when the elongation is 50%.

The other examples and comparative examples were evaluated in the same manner. The evaluation results are shown in Table 1.

As can be seen from Table 1, the primer compositions of the examples all have excellent workability, subsequent application adhesion, and barrier properties. The tensile adhesion under various conditions also shows good properties when the primer compositions of the examples are used. Referring to the examples and the comparative examples, it can be seen that the combination of component (A) and component (B) exhibits good workability, subsequent application adhesion, and barrier properties.

The above describes the embodiments and examples of the present invention, but the embodiments and examples described above do not limit the scope of the invention to be applied for. In addition, it should be noted that the combination of features described in all embodiments and examples is not necessarily a necessary means for solving the problem of the present invention; and various modifications are possible as long as they do not deviate from the technical idea of the present invention.

without.

without.

without.

Claims (5)

A primer composition comprising: (A) a methyl methacrylate polymer having a weight average molecular weight of 60,000 to 140,000, wherein the proportion of methyl methacrylate contained in the resin is 80% by weight or more; and (B) a methyl methacrylate polymer containing an alkoxysilyl group, wherein the proportion of methyl methacrylate contained in the resin is less than 80% by weight, wherein the addition amount of component (A) is 1% to 20% relative to the primer composition. The primer composition of claim 1 further comprises: (C) silane containing an amino group. The primer composition of claim 1 or 2 further comprises: (D) epoxy resin. The primer composition of claim 1 or 2 further comprises: (E) a silane-based crosslinking agent. The primer composition of claim 3 further comprises: (E) a silane-based crosslinking agent.