WO2024225074A1 - Method for producing (meth)acryloyl group-containing organopolysiloxane - Google Patents

Abstract

[Problem] A purpose of the present invention is to provide a method for producing a new (meth)acryloyl group-containing organopolysiloxane that has easy control of reaction conditions, good availability of raw materials, and favorable reaction efficiency. [Solution] A method for producing a (meth)acryloyl group-containing organopolysiloxane, the method including a step for obtaining a (meth)acryloyl group-containing organopolysiloxane by reacting (A) an organopolysiloxane selected from the group consisting of a halogen-containing organopolysiloxane (a-1) represented by the average compositional formula (1) below and a halogen-containing organopolysiloxane (a-2) represented by the average compositional formula (2) below (in formula (1), R¹ are each independently a halogen-containing alkyl group having 1-11 carbon atoms, R² are each independently a group selected from a substituted or unsubstituted monovalent hydrocarbon group having 1-11 carbon atoms, an alkoxy group having 1-11 carbon atoms, and an organic group having a hydroxyl group, and a and b are numbers satisfying a≥1, b≥0, and 20≥a+b≥3) (in formula (2), R³ and R³' are each independently a group selected from the choices of R¹ and R², at least one among R³ and R³' is a group represented by R¹, and c, d, e, and f are numbers satisfying c≥2, d≥0, e≥0, f≥0, 2≤c+d+e+f≤1,000), and (B) (meth)acrylic acid metal salt in the presence of (C) a phase transfer catalyst selected from a quaternary ammonium salt having at least one monovalent hydrocarbon group having 4-20 carbon atoms, a crown ether, and a phosphonium compound.

Description

Method for producing (meth)acryloyl group-containing organopolysiloxane

The present invention relates to a method for producing (meth)acryloyl group-containing organopolysiloxane.

The technique of applying energy to liquid resin compositions to harden them is a widely used technology, and is used in many fields to create coatings and molded products. The energy required for hardening can be heat or radiation such as ultraviolet light. In the case of heat hardening, a catalyst that is activated by heat is mixed into the base resin, and a hardened product is obtained by applying heat. In the case of radiation hardening, a composition that contains a photoinitiator that is activated by ultraviolet light or other radiation is hardened by irradiating it with radiation.

Typical functional groups used in radiation curing include (meth)acryloyl, mercapto, and epoxy groups. (Meth)acryloyl groups form crosslinks through radical polymerization reactions, and mercapto groups undergo radical ene-thiol reactions in the presence of alkenyl groups. Epoxy groups undergo cationic polymerization in the presence of acids.

Various resins are used for this type of radiation curing, one of which is silicone. Silicone is a general term for organopolysiloxanes that have continuous siloxane bonds in the main chain and organic groups such as methyl groups in the side chains. Silicones have excellent heat resistance, cold resistance, chemical resistance, electrical insulation, and releasability, and can be made into various forms such as oil, rubber, and resin. Radiation-curable silicones are the raw material for cured products such as silicone rubber, silicone for release paper, and silicone for hard coats.

Organopolysiloxanes containing (meth)acryloyl groups as radiation-polymerizable groups are used in release coatings, hard coats, and as surface tension adjusters. A photopolymerization initiator is added to this base material, and the material is irradiated with radiation while purging with nitrogen in a chamber to efficiently react with the radicals generated by radiation, resulting in a cured product.

Several studies have been conducted on methods for producing such organopolysiloxanes containing (meth)acryloyl groups. In Patent Document 1, an organopolysiloxane containing (meth)acryloyl groups is produced by using an epoxy-modified organopolysiloxane as a raw material and reacting (meth)acrylic acid with an epoxy group. However, in this case, hydroxyl groups are generated as the epoxy ring opens, and the viscosity of the product increases, leaving an issue in terms of handling.

Patent Document 2 proposes a method of introducing acryloyl groups into siloxanes containing methoxy groups by reacting them with hydroxyethyl acrylate and heating them, accompanied by the distillation of methanol. However, the product obtained by this method contains hydrolyzable silicon-oxygen-carbon bonds, leaving issues in terms of storage stability.

Patent Document 3 discloses a method for introducing a (meth)acryloyl group into a siloxane compound by reacting a siloxane compound having a Cl-containing organic group with an alkali metal salt of (meth)acrylic acid in the presence of tetramethylammonium chloride. This is one of the most effective manufacturing methods, but the activity of tetramethylammonium chloride is low, so there is an issue that the reaction efficiency is poor depending on the type of siloxane compound having a Cl-containing organic group.

JP 2018-521188 A JP 2016-209874 A JP 2021-17424 A

As mentioned above, the conventional methods for producing (meth)acryloyl group-containing organopolysiloxanes have problems with handling and reaction efficiency. Therefore, the object of the present invention is to provide a new method for producing (meth)acryloyl group-containing organopolysiloxanes that allows easy control of reaction conditions, good availability of raw materials, and good reaction efficiency.

As a result of extensive research into achieving the above object, the inventors have discovered that (meth)acryloyl-modified organopolysiloxanes can be efficiently synthesized by reacting an organopolysiloxane having a halogen-containing organic group with a (meth)acrylate salt in the presence of a phase transfer catalyst.

（式中、Ｒ^１は、互いに独立に、ハロゲン含有の炭素数１～１１のアルキル基であり、Ｒ^２は、互いに独立に、置換又は非置換の、炭素数１～１１の１価炭化水素基、炭素数１～１１のアルコキシ基、及び、水酸基を有する有機基から選択される基であり、ａ及びｂは、ａ≧１、ｂ≧０、２０≧ａ＋ｂ≧３を満たす数である）

（式中、Ｒ^３及びＲ^３’は、互いに独立に、上記Ｒ^１及びＲ^２の選択肢から選ばれる基であり、Ｒ^３及びＲ^３’のうち少なくとも１つは上記Ｒ^１で示される基であり、ｃ、ｄ、ｅ、ｆは、ｃ≧２、ｄ≧０、ｅ≧０、ｆ≧０、２≦ｃ＋ｄ＋ｅ＋ｆ≦１，０００を満たす数である）、及び
（Ｂ）（メタ）アクリル酸金属塩を、
（Ｃ）炭素数４～２０の一価炭化水素基を少なくとも１つ有する第４級アンモニウム塩、クラウンエーテル、及びホスホニウム化合物から選ばれる相間移動触媒
の存在下で反応させて（メタ）アクリロイル基含有オルガノポリシロキサンを得る工程を含む、前記（メタ）アクリロイル基含有オルガノポリシロキサンの製造方法を提供する。 That is, the present invention provides an organopolysiloxane selected from the group consisting of (A) a halogen-containing organopolysiloxane (a-1) represented by the following average composition formula (1) and (a-2) represented by the following average composition formula (2):

(In the formula, R ¹ 's are each independently a halogen-containing alkyl group having 1 to 11 carbon atoms, R ² 's are each independently a substituted or unsubstituted group selected from a monovalent hydrocarbon group having 1 to 11 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, and an organic group having a hydroxyl group, and a and b are numbers that satisfy a≧1, b≧0, and 20≧a+b≧3.)

(wherein R ³ and R ³ ' are each independently a group selected from the options for R ¹ and R ² above, at least one of R ³ and R ³ ' is a group represented by R ¹ above, and c, d, e, and f are numbers satisfying c≧2, d≧0, e≧0, f≧0, and 2≦c+d+e+f≦1,000), and (B) a metal (meth)acrylate,
and (C) a step of reacting in the presence of a phase transfer catalyst selected from a quaternary ammonium salt having at least one monovalent hydrocarbon group having 4 to 20 carbon atoms, a crown ether, and a phosphonium compound to obtain a (meth)acryloyl group-containing organopolysiloxane.

The present invention further provides the above-mentioned production method, which further satisfies at least one of the following constituent requirements [1] to [9]:
[1] A method for producing the (meth)acryloyl group-containing organopolysiloxane, characterized in that the number of silicon atoms to which R ¹ is bonded in the halogen-containing organopolysiloxane (a-2) represented by the average composition formula (2) is 1 to 100% based on the total number of silicon atoms.
[2] A method for producing the (meth)acryloyl group-containing organopolysiloxane, characterized in that the (B) component is blended in an amount of 1 to 3 moles per mole of halogen atoms contained in the (A) component, and further, the (C) component is blended in an amount of 0.05 to 10 parts by mass per 100 parts by mass of the (A) component.
[3] The method for producing the (meth)acryloyl group-containing organopolysiloxane, wherein the (B) metal (meth)acrylate is an alkali metal salt.
[4] The phase transfer catalyst (C) is represented by the following formula (3):
R ⁴ ₄ N ⁺ X ^- (3)
(In the formula, R ⁴ is, independently of each other, a hydrogen atom or a linear or branched monovalent hydrocarbon group having 1 to 20 carbon atoms, with the proviso that at least one of R ⁴ is a linear or branched monovalent hydrocarbon group having 4 to 20 carbon atoms, and X ⁻ is a halide ion.)
The (meth)acryloyl group-containing organopolysiloxane is a quaternary ammonium salt represented by the formula:
[5] The method for producing the (meth)acryloyl group-containing organopolysiloxane, wherein the phase transfer catalyst (C) is a quaternary ammonium salt represented by the above formula (3), and the halide ion is Br 4 ^- or Cl 4 ^- .
[6] The method for producing the aforementioned (meth)acryloyl group-containing organopolysiloxane, wherein each R ¹ in component (A) is independently an alkyl group having 1 to 7 carbon atoms and containing a halogen at the terminal.
[7] A method for producing the aforementioned (meth)acryloyl group-containing organopolysiloxane, wherein in the aforementioned average composition formula (2), 1≦d≦998, and at least one of R ³ ' is a group represented by the aforementioned R ¹ .
[8] A method for producing the above (meth)acryloyl group-containing organopolysiloxane, wherein in the above average composition formula (2), 1≦d≦998, at least one of R ³ ' is a group represented by the above R ¹ , and each of the R ¹ 's is independently an alkyl group having 1 to 5 carbon atoms and a halogen atom at its terminal.
[9] The method for producing the (meth)acryloyl group-containing organopolysiloxane, further comprising blending (D) a polymerization inhibitor in an amount of 0.01 to 1 part by mass per 100 parts by mass of the total of the components (A) and (B).

The manufacturing method of the present invention allows the desired (meth)acryloyl group-containing organopolysiloxane to be obtained efficiently through a desalting reaction using inexpensive raw materials.

The present invention will be described in detail below.

（式中、Ｒ^１は、互いに独立に、ハロゲン含有の炭素数１～１１のアルキル基であり、Ｒ^２は、互いに独立に、置換又は非置換の、炭素数１～１１の１価炭化水素基、炭素数１～１１のアルコキシ基、及び、水酸基を有する有機基から選択される基であり、ａ及びｂは、ａ≧１、ｂ≧０、２０≧ａ＋ｂ≧３を満たす数である）

（式中、Ｒ^３及びＲ^３’は、互いに独立に、上記Ｒ^１及びＲ^２の選択肢から選ばれる基であり、Ｒ^３及びＲ^３’のうち少なくとも１つは上記Ｒ^１で示される基であり、ｃ、ｄ、ｅ、ｆは、ｃ≧２、ｄ≧０、ｅ≧０、ｆ≧０、２≦ｃ＋ｄ＋ｅ＋ｆ≦１，０００を満たす数である）。 [Component (A)]
Component (A) is at least one organopolysiloxane selected from the group consisting of halogen-containing organopolysiloxane (a-1) represented by the following average composition formula (1) and halogen-containing organopolysiloxane (a-2) represented by the following average composition formula (2):

(In the formula, R ¹ 's are each independently a halogen-containing alkyl group having 1 to 11 carbon atoms, R ² 's are each independently a substituted or unsubstituted group selected from a monovalent hydrocarbon group having 1 to 11 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, and an organic group having a hydroxyl group, and a and b are numbers that satisfy a≧1, b≧0, and 20≧a+b≧3.)

(In the formula, ^R3 and ^R3 ' are each independently a group selected from the options for ^R1 and ^R2 above, at least one of ^R3 and ^R3 ' is a group represented by ^R1 above, and c, d, e, and f are numbers satisfying c≧2, d≧0, e≧0, f≧0, and 2≦c+d+e+f≦1,000).

^R1 's are each independently an alkyl group having 1 to 11 carbon atoms, preferably an alkyl group having 1 to 7 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and further preferably an alkyl group having 1 to 3 carbon atoms, which has a halogen at its terminal.

^R2 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 11 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, or a hydroxyl group-containing organic group. Examples of the monovalent hydrocarbon group having 1 to 11 carbon atoms include alkyl groups such as methyl, ethyl, propyl, and butyl groups, cycloalkyl groups such as cyclohexyl groups, and aryl groups such as phenyl and tolyl groups. Examples of the alkoxy group having 1 to 11 carbon atoms include methoxy, ethoxy, isopropoxy, and butoxy groups. Examples of the hydroxyl group-containing organic group include hydroxymethyl, hydroxyethyl, hydroxypropyl, and hydroxybutyl groups. ^R2 is preferably a methyl, ethyl, methoxy, ethoxy, or hydroxyl group-containing organic group.

In the above average composition formula (2), R ³ and R ³ ' are each independently a group selected from the options of R ¹ and R ² , and at least one of R ³ and R ³ ' is a group represented by R ^1. Preferably, at least one of R ³ ' is a group represented by R ^1. Therefore, preferably, in the above average composition formula (2), 1≦d≦998, and at least one of R 3 ' is an alkyl group having 1 to 7 carbon atoms and a halogen at the end, more preferably an alkyl group having 1 to 5 carbon atoms, and even more preferably an alkyl group having 1 to 3 ^{carbon atoms. More preferably, R 3 is} a group selected from the options of R ² , that is, a monovalent hydrocarbon group having 1 to 11 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, or a hydroxyl group-containing organic group, and even more preferably, R ³ is an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group, or a hydroxyl group-containing organic group.

In the above average composition formula (2), the ratio of the number of silicon atoms bonded to a halogen-containing alkyl group having 1 to 11 carbon atoms (i.e., R ¹ ) to the total number of all silicon atoms is preferably 1 to 100%, more preferably 3 to 75%, more preferably 5 to 50%, and even more preferably 5 to 30%. In particular, if the number of silicon atoms bonded to a halogen-containing alkyl group having 1 to 11 carbon atoms is less than 1%, the curability when cured by radiation may be insufficient.

Examples of R ¹ include halogen alkyl groups such as chloromethyl, chloroethyl, chloropropyl, chlorobutyl, chloropentyl, chlorohexyl, chlorooctyl, bromomethyl, bromoethyl, bromopropyl, bromobutyl, bromopentyl, bromohexyl, bromooctyl, iodomethyl, iodoethyl, iodopropyl, iodobutyl, iodopentyl, iodohexyl, and iodooctyl. From the viewpoint of ease of reaction, the substitution position of the halogen atom is preferably primary or secondary, and more preferably primary. In addition, from the viewpoint of ease of availability of raw materials for functional groups, the number of carbon atoms of the halogen-containing organic group is preferably 1 to 5. Furthermore, the halogen-containing organic group is preferably a chloroalkyl group or a bromoalkyl group, and particularly preferably a chloroalkyl group. Among them, a chloromethyl group, a chloroethyl group, and a chloropropyl group are preferable. The halogen-containing alkyl group having 1 to 11 carbon atoms, preferably 1 to 5 carbon atoms, may be linear or branched. R ¹ is represented, for example, by the following structure: In the following formula, the positions indicated by dotted lines are bonds to silicon atoms of the organopolysiloxane.

In the average composition formula (1), a and b are numbers that satisfy a ≧ 1, b ≧ 0, and 20 ≧ a + b ≧ 3, and preferably a is a number from 1 to 15, b is a number from 0 to 15, and a + b is a number from 3 to 15, and more preferably a is a number from 1 to 10, b is a number from 0 to 10, and a + b is a number from 3 to 10. Preferably, the organopolysiloxane has a viscosity at 25°C of 1 to 2,000 mPa·s, and more preferably a viscosity of 2 to 1,000 mPa·s. The viscosity is a value measured with a BM type rotational viscometer at 25°C.

（式中、ｇは１～２０であり、ｈは０～１９、ｉは０～１９であり、及び、２０≧ｇ＋ｈ＋ｉ≧３である） Examples of organopolysiloxanes represented by the average composition formula (1) include compounds represented by the following structures: In the formula, Me represents a methyl group, and Ph represents a phenyl group.

(In the formula, g is 1 to 20, h is 0 to 19, i is 0 to 19, and 20≧g+h+i≧3.)

In the average composition formula (2), c, d, e, and f are numbers that satisfy c≧2, d≧0, e≧0, f≧0, and 2≦c+d+e+f≦1,000. Preferably, c is a number from 2 to 32, d is a number from 0 to 998, d is preferably a number from 1 to 998, e is a number from 0 to 10, f is a number from 0 to 10, and c+d+e+f is 2 to 1000. More preferably, c is a number from 2 to 20, d is a number from 1 to 798, e is a number from 0 to 6, f is a number from 0 to 6, and c+d+e+f is 3 to 800. More preferably, c is 2, and d is a number from 1 to 600. Even more preferably, c is 2, and d is a number from 1 to 400. As described above, at least one of the R ³ ' groups bonded to the silicon atom of [R ³ 'R ³ 'SiO _2/2 ] _d should be a group represented by R ¹ above.
It is preferable that the ratio of silicon atoms bonded to the halogen-containing alkyl group (R ¹ ) having 1 to 11 carbon atoms falls within the above-mentioned range, and that the organopolysiloxane has a viscosity of 5 to 10,000 mPa·s, and more preferably a viscosity of 10 to 5,000 mPa·s, at 25° C. The viscosity is a value measured with a BM type rotational viscometer.

（式中、ｊは０～９９７であり、ｋは１～９９８、ｌは０～１００であり、１≦ｊ＋ｋ≦９９８、又は、０≦ｊ＋ｉ≦９９８を満たす） Examples of organopolysiloxanes represented by the average composition formula (2) include compounds represented by the following structures: In the formula, Me represents a methyl group, and Ph represents a phenyl group.

(In the formula, j is 0 to 997, k is 1 to 998, and l is 0 to 100, and 1≦j+k≦998 or 0≦j+i≦998 is satisfied.)

[Component (B)]
Component (B) is a metal (meth)acrylate, which is a reaction agent for introducing a (meth)acryloyl group into component (A). Component (B) is preferably a metal (meth)acrylate represented by the following general formula (4). More preferably, it is an alkali metal salt.

In formula (4), ^R5 is a hydrogen atom or a methyl group, and Mm ⁺ is a metal ion. Examples of the metal ion include potassium ion, sodium ion, calcium ion, and zinc ion. Among them, from the viewpoint of ease of proceeding of the desalting reaction, Mm ⁺ is preferably an alkali metal ion, and more preferably a potassium ion. m is an integer of 1 to 2, and preferably 1.

The amount of component (B) to be reacted is 1 to 3 moles, preferably 1 to 2 moles, and more preferably 1.01 to 1.5 moles per mole of halogen atoms in organopolysiloxane (A). If the amount of component (B) is less than the lower limit above, the introduction rate of (meth)acryloyl groups by the desalting reaction decreases. If it is more than the upper limit above, the introduction rate of (meth)acryloyl groups by the desalting reaction increases, but the amount of component (B) is too large, which may result in a decrease in pot yield or an increase in the viscosity of the reaction mixture, making handling difficult.

[Component (C)]
Component (C) is a phase transfer catalyst selected from quaternary ammonium salts having at least one monovalent hydrocarbon group having 4 to 20 carbon atoms, crown ethers, and phosphonium compounds, and is preferably a quaternary ammonium salt represented by the following general formula (3):
R ⁴ ₄ N ⁺ X ^- (3)
(In the formula, R ⁴ is, independently of each other, a hydrogen atom or a linear or branched monovalent hydrocarbon group having 1 to 20 carbon atoms, provided that at least one of R ⁴ is a linear or branched monovalent hydrocarbon group having 4 to 20 carbon atoms, and X ⁻ is a halide ion.)

R ⁴ is, independently of each other, a hydrogen atom or a linear or branched monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 18 carbon atoms, and more preferably 1 to 16 carbon atoms. However, at least one of R ⁴ is a linear or branched hydrocarbon group having 4 to 20 carbon atoms, preferably 4 to 18 carbon atoms, and more preferably 4 to 16 carbon atoms. Examples of R ⁴ include alkyl groups such as methyl, ethyl, propyl, n-butyl, isopropyl, t-butyl, pentyl, hexyl, and octyl groups, cycloalkyl groups such as cyclohexyl, and phenyl groups. Among them, from the viewpoint of efficiency of the desalting reaction, R ⁴ is preferably a linear alkyl group, and more preferably an n-butyl group, an n-pentyl group, or an n-hexyl group.

The reason why the reaction efficiency improves when ^R4 is an alkyl group such as a butyl group, a pentyl group, or a hexyl group is believed to be that the presence of an alkyl group with a long chain length improves the compatibility of the ammonium (meth)acrylate salt, which is generated by the ion exchange reaction between the quaternary ammonium salt, which is the phase transfer catalyst, and the metal (meth)acrylate salt, with silicone, making it easier to promote the reaction.

X ⁻ is a halide ion, and is preferably Br 2 ⁻ or Cl 2 ⁻ from the viewpoint of availability.

Examples of the phase transfer catalyst represented by formula (3) include compounds represented by the following structures:

The amount of component (C) is 0.05 to 10 parts by mass, preferably 0.1 to 7.5 parts by mass, and more preferably 0.3 to 5 parts by mass, per 100 parts by mass of component (A). If the amount is less than the lower limit, the reaction may not proceed sufficiently. If the amount exceeds the upper limit, the curing property when cured by radiation may decrease. In addition, only one type of phase transfer catalyst may be used, or two or more types may be selected from the above.

[Component (D)]
Component (D) is a polymerization inhibitor, which is an additive for suppressing self-polymerization of (B) metal (meth)acrylate without reacting with component (A) during the reaction. The polymerization inhibitor is not limited as long as it has the effect of suppressing radical polymerization, and examples of the polymerization inhibitor include alkylphenols such as those listed below.

p-Methoxyphenol, 2,6-di-t-butylhydroxytoluene, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, 4,4'-dioxydiphenol, 1,1'-bis(4-hydroxyphenyl)-cyclohexane, 3-methyl-4-isopropylphenol, 2,4,5-tri-hydroxybutyrophenone, 2,6-di-t-butylphenol, 2,5-di-t-amylhydroquinone, 2,5-di-t-butylhydroquinone, 4-hydroxymethyl-2,6-di-t-butylphenol, 2,6-di-t-butyl-α-dimethylamino-p -cresol, 4,4-bis(2,6-di-butylphenol), 2,2'-methylene-bis(4-ethyl-6-t-butylphenol), 2,2'-methylene(2,6-di-t-butylphenol), 4,4'-methylene(2,6-di-t-butylphenol), 4,4'-butylidene(3-methyl-6-t-butylphenol), 4,4'-thio-bis(6-t-butyl-3-methylphenol), bis(3-methyl-4-hydroxy-5-t-butylbenzyl)sulfide, 4,4'-thio-bis(6-t-butyl-o-cresol), and 2,2'-thio-bis(4-methyl-6-t-butylphenol).

　Amine-based polymerization inhibitors can also be used, such as those listed below.

Alkylated diphenylamines, N,N'-diphenyl-p-phenylenediamine, phenothiazine, 4-hydroxy-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1,4-dihydroxy-2,2,6,6-tetramethylpiperidine, 1-hydroxy-4-benzoyloxy-2,2,6,6-tetramethylpiperidine.

The amount of polymerization inhibitor is 0.01 to 1 part by mass, preferably 0.02 to 0.5 parts by mass, and more preferably 0.03 to 0.3 parts by mass, per 100 parts by mass of the total of components (A) and (B). If the amount of component (D) is more than the above upper limit, the curability of the resulting radiation-curable organopolysiloxane composition containing the radically polymerizable organopolysiloxane may decrease. If the amount of component (D) is less than the above lower limit, there is a concern that the (meth)acrylic acid may polymerize during production, causing thickening or gelation. Furthermore, only one type of polymerization inhibitor may be used, or two or more types may be selected from the above and used.

[solvent]
The desalting reaction of the present invention may be carried out either without a solvent or in an organic solvent, but is preferably carried out in an organic solvent from the viewpoint of the ease of reaction progression. As the organic solvent, it is preferable to select and use one or more types from high polarity solvents, and it is more preferable to select and use one or more types from each of high polarity solvents and low polarity solvents. The amount of the solvent is preferably 0 to 200 parts by mass, more preferably 0 or 1 to 150 parts by mass, per 100 parts by mass of component (A).

In this reaction, the addition of a highly polar solvent allows the reaction to proceed efficiently. When using a protic solvent, it is preferable to use an aprotic solvent because the halogen atoms may react with the solvent. Furthermore, it is preferable to use a solvent with a high boiling point so that it can be used as a solvent even at high reaction temperatures. Although the detailed mechanism of the reaction has not been clarified, it is believed that the addition of a highly polar solvent improves the solubility of the metal (meth)acrylate salt in the organic phase, promoting the reaction between the halogen-containing silicone, which is an organic substance, and the metal (meth)acrylate salt, which is an inorganic salt. The amount of the highly polar solvent is preferably 0 or 1 to 50 parts by weight, more preferably 5 to 45 parts by weight, and even more preferably 10 to 40 parts by weight, per 100 parts by weight of component (A).

Examples of the aprotic highly polar solvents include ether-based solvents such as diethyl ether, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, and dipropylene glycol dimethyl ether; ester-based solvents such as ethyl acetate and butyl acetate; nitrogen-containing solvents such as N,N-dimethylformamide, acetonitrile, and N-methyl-2-pyrrolidone; and mixed solvents of these. These can be used alone or in appropriate combinations of two or more.

In this reaction, a purification procedure is performed after the reaction is completed, but this can be made easier by adding a low-polarity solvent. Purification procedures include water washing, filtration, stripping, distillation, etc., and these can be performed alone or in appropriate combination of two or more. Furthermore, if the acrylic group content is high, thickening or gelling can be suppressed by diluting the reaction with a low-polarity solvent.

Low polarity solvents include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, heptane, octane, isooctane, cyclohexane, methylcyclohexane, and isoparaffin, and hydrocarbon solvents such as industrial gasoline, petroleum benzine, and solvent naphtha, or mixed solvents of these. These can be used alone or in appropriate combinations of two or more. The amount of low polarity solvent is preferably 0 to 200 parts by mass, more preferably 0 or 1 to 150 parts by mass, per 100 parts by mass of component (A).

[Desalting reaction]
In the present invention, the halogen atoms contained in component (A) and the acryloyl oxide moieties of component (B) are subjected to a desalting reaction using the catalyst component (C) to obtain the target organopolysiloxane. The reaction is outlined below. Specific examples of ≡Si-R-X in the formula are those explained in the section on component (A) above. X represents a halogen.

The reaction temperature can be 50 to 150°C, preferably 60 to 145°C, and more preferably 70 to 140°C. If the temperature is lower than the lower limit, the reaction may not proceed sufficiently. If the temperature is higher than the upper limit, there is a concern that the (meth)acrylic acid ester of component (B) may polymerize and cause thickening and gelation. The reaction time may be in the range of 1 to 72 hours, but is not limited to this. The reaction atmosphere may be a nitrogen atmosphere or air, or a mixed gas such as nitrogen containing a small amount of oxygen may be used. The amount of oxygen in this case is 0.1 to 20%, preferably 0.5 to 18%, and more preferably 1 to 15%, calculated by volume.

After the reaction is complete, the resulting salts are removed by washing with water or filtration, and the product can be obtained by dehydrating with Glauber's salt or removing low molecular weight components by vacuum stripping. The temperature during stripping should be between 20°C and 130°C, and the vacuum should be between 1 and 200 mmHg (0.133 kPa and 26.664 kPa), but this is not a limitation.

（式中、Ｒ^６は、互いに独立に、（メタ）アクリロイル基含有の炭素数１～１１のアルキル基であり、Ｒ^７は、互いに独立に、炭素数１～１１の１価炭化水素基、炭素数１～１１のアルコキシ基、水酸基を有する有機基から選択される基であり、ｎ及びｏは、ｎ≧１、ｏ≧０、２０≧ｎ＋ｏ≧３を満たす数である）

（式中、Ｒ^８及びＲ^８’は、互いに独立に、Ｒ^６及びＲ^７の選択肢から選ばれる基であり、Ｒ^８及びＲ^８’のうち少なくとも１つはＲ^６である。また、ｐ、ｑ、ｒ、ｓは、ｐ≧２、ｑ≧０、ｒ≧０、ｓ≧０、２≦ｐ＋ｑ＋ｒ＋ｓ≦１，０００を満たす数である。） The (meth)acryloyl group-containing organopolysiloxane obtained in the present invention is represented by the following average composition formula (5) or (6).

(In the formula, R ⁶ are each independently an alkyl group having 1 to 11 carbon atoms and containing a (meth)acryloyl group, R ⁷ are each independently a group selected from a monovalent hydrocarbon group having 1 to 11 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, and an organic group having a hydroxyl group, and n and o are numbers that satisfy n≧1, o≧0, and 20≧n+o≧3.)

(In the formula, ^R8 and ^R8 ' are each independently a group selected from the options of ^R6 and ^R7 , and at least one of ^R8 and ^R8 ' is ^R6 . In addition, p, q, r, and s are numbers that satisfy p≧2, q≧0, r≧0, s≧0, and 2≦p+q+r+s≦1,000.)

In the formula, ^R6 is an alkyl group having 1 to 11 carbon atoms and a (meth)acryloyl group at its terminal (hereinafter collectively referred to as a (meth)acryloyl group-containing group). The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

In the formula, R ⁷ is independently a group selected from a monovalent hydrocarbon group having 1 to 11 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, and an organic group having a hydroxyl group, and the examples for R ² described above apply.

In the formula, R ⁸ and R ⁸ ' are groups defined as R ⁶ or R ⁷ above. The number of silicon atoms to which (meth)acryloyl-containing groups are bonded is preferably 1 to 100%, more preferably 3 to 75%, even more preferably 5 to 50%, and even more preferably 5 to 30% of the total number of silicon atoms. More preferably, at least one of R ⁸ ' is R ^6. In the average composition formula (6), p, q, r, and s are numbers that satisfy p≧2, q≧0, r≧0, s≧0, and 2≦p+q+r+s≦1,000. Preferably, p is a number from 2 to 32, q is a number from 0 to 998, r is a number from 0 to 10, s is a number from 0 to 10, and p+q+r+s is a number from 2 to 1000, and more preferably, p is a number from 2 to 20, q is a number from 1 to 798, r is a number from 0 to 6, s is a number from 0 to 6, and p+q+r+s is a number from 3 to 800. More preferably, p is a number from 2 and q is a number from 1 to 600. Even more preferably, p is a number from 2 and q is a number from 1 to 400, and at least one of the R ⁸ 's bonded to the silicon atom of [R ⁸ 'R ⁸ 'SiO _2/2 ] _d is R ⁶ .

The (meth)acryloyl group-containing group is a group in which the terminal halogen atom of the halogen-containing group represented by ^R1 above has been substituted with a (meth)acryloyloxy group, i.e., an alkyl group having 1 to 11 carbon atoms and one (meth)acryloyloxy group at the terminal, and is represented, for example, by the following structure: In the following formula, the site indicated by the dotted line is the bond to the silicon atom of the polysiloxane.

^R9 is a hydrogen atom or a methyl group.

In the average composition formula (5), n ≧ 1, o ≧ 0, and 20 ≧ n + o ≧ 3. Preferably, the organopolysiloxane has a viscosity of 1 to 2,000 mPa·s at 25°C, and more preferably a viscosity of 2 to 1,000 mPa·s. The viscosity is a value measured with a BM type rotational viscometer at 25°C.

（式中、ｔは１～２０であり、ｕは０～１９、ｖは０～１９である。２０≧ｔ＋ｕ＋ｖ≧３である） Examples of organopolysiloxanes represented by the average composition formula (5) include compounds represented by the following structures: In the formula, Me represents a methyl group, and Ph represents a phenyl group.

(In the formula, t is 1 to 20, u is 0 to 19, and v is 0 to 19. 20≧t+u+v≧3.)

In the average composition formula (6), p≧2, q≧0, r≧0, s≧0, and 2≦p+q+r+s≦1,000. Preferably, the amount of (meth)acryloyl group-containing organic groups satisfies the above range, and the organopolysiloxane has a viscosity of 5 to 10,000 mPa·s at 25°C, and more preferably a viscosity of 10 to 5,000 mPa·s. The (meth)acryloyl group-containing organopolysiloxane obtained by the above production method of the present invention can have a low viscosity. It can have a viscosity of preferably 5 to 3,000 mPa·s, more preferably 5 to 2,000 mPa·s, even more preferably 8 to 1,500 mPa·s, even more preferably 10 to 1,000 mPa·s, and particularly preferably 15 to 700 mPa·s. The viscosity is a value measured by a BM type rotational viscometer.

（式中、ｗは０～９９７であり、ｘは１～９９８、ｙは０～１００である。１≦ｗ＋ｘ≦９９８であり、０≦ｗ＋ｙ≦９９８である） Examples of organopolysiloxanes represented by the average composition formula (6) include compounds represented by the following structures: In the formula, Me represents a methyl group, and Ph represents a phenyl group.

(In the formula, w is 0 to 997, x is 1 to 998, and y is 0 to 100. 1≦w+x≦998, and 0≦w+y≦998.)

The present invention will be explained in more detail below with examples and comparative examples, but the present invention is not limited to the following examples. Note that parts in the examples are parts by weight.

[(Meth)acryloyl group introduction rate]
The introduction rate of (meth)acryloyl groups in the desalting reaction in the Examples and Comparative Examples was calculated as follows: The introduction rate of (meth)acryloyl groups in the present invention was calculated using ^1H -NMR to determine the sum of the integrals of the protons (δ=3.49) of the methylene groups bonded to the halogen atoms of the raw material organopolysiloxane containing an alkyl group having a halogen atom, and the protons (δ=4.11) of the methylene groups bonded to the (meth)acryloyloxy groups generated as the reaction progresses and the halogen atoms are replaced by (meth)acryloyloxy groups, since this value remains unchanged before and after the reaction. For example, when the sum of the integrals of the protons of the methylene group bonded to the halogen atom (δ=3.49) and the protons of the methylene group bonded to the (meth)acryloyloxy group (δ=4.11) is taken as 1.00, if the introduction rate of the (meth)acryloyl group by the desalting reaction is 100%, the integral of the protons of the methylene group bonded to the (meth)acryloyloxy group (δ=4.11) will be 1.00. From this, the introduction rate of the (meth)acryloyl group was calculated according to the following formula:
(Meth)acryloyl group introduction rate=[integral value of protons (δ=4.11) of methylene groups bonded to (meth)acryloyloxy groups/1.00]×100 (%)

（全ケイ素原子数に対するハロゲン含有基が結合するケイ素原子数の比率は５．７％）

[Example 1]
A separable flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 140 g of an organopolysiloxane represented by the average compositional formula (A-1) below (viscosity at 25° C.: 200 mPa·s), 11.76 g of potassium acrylate (B-1) (an amount equivalent to 1.05 molar equivalents per mole of halogen atoms in the organopolysiloxane (A-1)), 1.89 g of tetrabutylammonium bromide (C-1), 0.07 g of 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate (D-1), and 30 g of N,N-dimethylformamide as a solvent, and the mixture was heated and stirred for 7 hours at a temperature such that the inside of the reaction system reached 120° C. while blowing 4% oxygen-mixed nitrogen gas into the reaction solution through a glass tube, to carry out the reaction. Toluene was added to this reaction mixture, and the salt was removed by washing with water, after which the toluene and other components were removed by vacuum stripping at 100° C. for 4 hours at 15 mmHg, yielding an organopolysiloxane represented by the following average compositional formula (X-1). The target product was brown and transparent, and the introduction rate of acryloyl groups was 97%.

(The ratio of the number of silicon atoms bonded to halogen-containing groups to the total number of silicon atoms is 5.7%)

[Example 2]
The procedure of Example 1 was repeated except that the amount of (C-1) was increased to 4.00 g and 30 g of N,N-dimethylformamide was omitted, to obtain an organopolysiloxane represented by the average compositional formula (X-1). The target product was a brown, transparent product, and had an acryloyl group introduction rate of 64%.

（全ケイ素原子数に対するハロゲン含有基が結合するケイ素原子数の比率は５．７％）

[Example 3]
Example 1 was repeated, except that 140 g of an organopolysiloxane (viscosity at 25°C 200 mPa·s) represented by the following average compositional formula (A-2) was used instead of (A-1) in Example 1, to obtain an organopolysiloxane represented by the following average compositional formula (X-2). The target product was brown and transparent, and the acryloyl group introduction rate was 97%.

(The ratio of the number of silicon atoms bonded to halogen-containing groups to the total number of silicon atoms is 5.7%)

（全ケイ素原子数に対するハロゲン含有基が結合するケイ素原子数の比率は２０％） 

[Example 4]
A separable flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 70 g of an organopolysiloxane represented by the average compositional formula (A-3) below (viscosity at 25° C.: 200 mPa·s), 17.86 g of potassium acrylate (B-1) (an amount equivalent to 1.01 molar equivalents per mole of halogen atoms in the organopolysiloxane (A-3)), 0.26 g of tetrabutylammonium bromide (C-1), 0.05 g of 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, and 14 g of N,N-dimethylformamide as a solvent, and the mixture was heated and stirred for 3 hours at a temperature such that the inside of the reaction system reached 120° C. while blowing 4% oxygen-mixed nitrogen gas into the reaction solution through a glass tube to effect a reaction. Toluene was added to this reaction mixture, and the salt was removed by washing with water, after which the toluene and other components were removed by vacuum stripping at 115° C. for 3 hours at 18 mmHg, yielding an organopolysiloxane represented by the following average compositional formula (X-3). The target product was a pale pink transparent product, and the introduction rate of acryloyl groups was 96%.

(The ratio of the number of silicon atoms bonded to halogen-containing groups to the total number of silicon atoms is 20%)

[Example 5]
Into a separable flask equipped with a stirrer, a thermometer, and a reflux condenser, 200 g of an organopolysiloxane represented by the following average compositional formula (A-4) (viscosity at 25°C: 60 mPa·s), 169 g of (B-1) potassium acrylate (an amount equivalent to 1.05 molar equivalents per mole of halogen atoms in the organopolysiloxane (A-4)), 1.88 g of (C-1) tetrabutylammonium bromide, and (D-1) 2-t-butylammonium bromide were added. 0.40 g of ethyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate, 0.04 g of (D-2) N,N'-diphenyl-p-phenylenediamine, 200 g of toluene as a solvent, and 80 g of N,N-dimethylformamide were charged, and while blowing 4% oxygen-mixed nitrogen gas into the reaction solution using a glass tube, the reaction was allowed to proceed with heating and stirring for 5 hours at a temperature at which the reaction system reached 115°C. Salts were removed from this reaction mixture by washing with water, and then toluene and the like were removed by a reduced pressure strip at 70°C for 5 hours at 7.7 mmHg, yielding an organopolysiloxane represented by the following average composition formula (X-4). The target product was brown and transparent, and the acryloyl group introduction rate was 98%.

[Example 6]
The procedure of Example 5 was repeated except that the amount of (C-1) was increased to 4.00 g and 80 g of N,N-dimethylformamide was omitted, to obtain an organopolysiloxane represented by the average compositional formula (X-4). The target product was a brown, transparent product, and the introduction rate of acryloyl groups was 97%.

[Example 7]
The procedure of Example 5 was repeated except that 6.00 g of (C-2) trioctylmethylammonium chloride was used instead of (C-1), 80 g of N,N-dimethylformamide was omitted, and the reaction time was changed to 7 hours, to obtain an organopolysiloxane represented by the average compositional formula (X-4). The target product was brown and transparent, and the introduction rate of acryloyl groups was 89%.

[Example 8]
Example 5 was repeated except that 200 g of an organopolysiloxane (viscosity at 25°C 70 mPa·s) represented by the following average compositional formula (A-5) was used instead of (A-4) and the amount of (B-1) potassium acrylate was changed to 129 g (an amount equivalent to 1.05 molar equivalents per mole of halogen atoms in the organopolysiloxane (A-5)), to obtain an organopolysiloxane represented by the average compositional formula (X-5). The target product was brown and transparent, and the acryloyl group introduction rate was 95%.

[Comparative Example 1]
An acrylic-modified silicone was produced using the catalyst tetramethylammonium chloride used in Examples 1 to 3 of Patent Document 3 (JP 2021-017424 A).
An attempt was made to synthesize an organopolysiloxane represented by the average compositional formula (X-1) by repeating Example 2, except that 4.00 g of tetramethylammonium chloride was used instead of (C-1) in Example 2. However, after 7 hours of reaction, the acryloyl group introduction rate was 0%, and the reaction did not proceed.

[Comparative Example 2]
An acrylic-modified silicone was produced using the catalyst tetramethylammonium chloride used in Examples 1 to 3 of Patent Document 3 (JP 2021-017424 A).
An attempt was made to synthesize an organopolysiloxane represented by the average composition formula (X-4) by repeating Example 5, except that 4.00 g of tetramethylammonium chloride was used instead of (C-1) and 80 g of N,N-dimethylformamide was omitted. However, after 5 hours of reaction, the acryloyl group introduction rate was 4%, and the reaction could not be completed.

In the method of the comparative example above, it is believed that the reaction did not proceed due to the low miscibility between the organopolysiloxane having chloropropyl groups and the organic salt. In contrast, in the manufacturing method of the present invention, as shown in Examples 1 to 6, the reaction proceeds sufficiently even with organopolysiloxane having chloropropyl groups.

[Comparative Example 3]
An attempt was made to synthesize an organopolysiloxane represented by average composition formula (X-4) by repeating Example 5, except for omitting (C-1) in Example 5. However, after 5 hours of reaction, the acryloyl group introduction rate was 2%, and the reaction could not be completed.

The method of the present invention makes it possible to simply and efficiently synthesize a (meth)acryloyl-modified organopolysiloxane by reacting an organopolysiloxane having a halogen-containing organic group with a (meth)acrylate salt. The (meth)acryloyl-modified organopolysiloxane obtained by the manufacturing method of the present invention is useful for radiation-curable coating agents, additives, resins, etc.

Claims (10)

(A) An organopolysiloxane selected from the group consisting of halogen-containing organopolysiloxanes (a-1) represented by the following average composition formula (1) and halogen-containing organopolysiloxanes (a-2) represented by the following average composition formula (2):

(In the formula, R ¹ 's are each independently a halogen-containing alkyl group having 1 to 11 carbon atoms, R ² 's are each independently a substituted or unsubstituted group selected from a monovalent hydrocarbon group having 1 to 11 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, and an organic group having a hydroxyl group, and a and b are numbers that satisfy a≧1, b≧0, and 20≧a+b≧3.)

(wherein R ³ and R ³ ' are each independently a group selected from the options for R ¹ and R ² above, at least one of R ³ and R ³ ' is a group represented by R ¹ above, and c, d, e, and f are numbers satisfying c≧2, d≧0, e≧0, f≧0, and 2≦c+d+e+f≦1,000), and (B) a metal (meth)acrylate,
(C) a step of reacting in the presence of a phase transfer catalyst selected from a quaternary ammonium salt having at least one monovalent hydrocarbon group having 4 to 20 carbon atoms, a crown ether, and a phosphonium compound to obtain a (meth)acryloyl group-containing organopolysiloxane. The method for producing a (meth)acryloyl group-containing organopolysiloxane according to claim 1, characterized in that the number of silicon atoms to which R ¹ is bonded in the halogen-containing organopolysiloxane (a-2) represented by the average composition formula (2) is 1 to 100% of the total number of silicon atoms. The method for producing a (meth)acryloyl group-containing organopolysiloxane according to claim 1, characterized in that the amount of the (B) component is 1 to 3 moles per mole of halogen atoms contained in the (A) component, and further, the amount of the (C) component is 0.05 to 10 parts by mass per 100 parts by mass of the (A) component. The method for producing a (meth)acryloyl group-containing organopolysiloxane according to claim 1, wherein the (B) (meth)acrylic acid metal salt is an alkali metal salt. The phase transfer catalyst (C) is represented by the following formula (3):
R ⁴ ₄ N ⁺ X ^- (3)
(In the formula, R ⁴ is, independently of each other, a hydrogen atom or a linear or branched monovalent hydrocarbon group having 1 to 20 carbon atoms, with the proviso that at least one of R ⁴ is a linear or branched monovalent hydrocarbon group having 4 to 20 carbon atoms, and X ⁻ is a halide ion.)
2. The method for producing the (meth)acryloyl group-containing organopolysiloxane according to claim 1, wherein the quaternary ammonium salt is represented by the formula: 6. The method for producing an organopolysiloxane containing a (meth)acryloyl group according to claim 5, wherein the phase transfer catalyst (C) is a quaternary ammonium salt represented by the above formula (3), and the halide ion is Br ^{2 -} or Cl 2 ^- . 2. The method for producing an organopolysiloxane containing a (meth)acryloyl group according to claim 1, wherein each R ¹ in component (A) is independently an alkyl group having 1 to 7 carbon atoms and containing a halogen at the terminal. 2. The method for producing an organopolysiloxane containing a (meth)acryloyl group according to claim 1, wherein in the average composition formula (2), 1≦d≦998, and at least one of R ³ ' is a group represented by R ¹ . The method for producing a (meth)acryloyl group-containing organopolysiloxane according to claim 1, wherein, in the average composition formula (2), 1≦d≦998, at least one of R ³ ' is a group represented by R ¹ , and each of the R ¹ 's is independently an alkyl group having 1 to 5 carbon atoms and a halogen atom at the terminal. The method for producing a (meth)acryloyl group-containing organopolysiloxane according to any one of claims 1 to 9, wherein in the above step, 0.01 to 1 part by mass of a polymerization inhibitor (D) is further blended per 100 parts by mass of the total of the components (A) and (B).