WO2023095556A1

WO2023095556A1 - Production method for (meth)acryloyl group-containing organopolysiloxane

Info

Publication number: WO2023095556A1
Application number: PCT/JP2022/040480
Authority: WO
Inventors: 理土田; 賢治田中
Original assignee: 信越化学工業株式会社
Priority date: 2021-11-25
Filing date: 2022-10-28
Publication date: 2023-06-01
Also published as: TW202337965A

Abstract

[Problem] The present invention aims to provide a novel transesterification production method whereby a (meth)acryloyl group-containing organopolysiloxane that is transparent and has a good external appearance can be obtained at reduced cost. [Solution] A production method for (meth)acryloyl group-containing organopolysiloxane that is characterized by including a step in which a hydroxyl group-containing organopolysiloxane (A) indicated by average formula (1) (in the formula, each R¹ is independently a substituted or unsubstituted C1–10 monovalent hydrocarbon group, an alkoxy group, or a monovalent hydrocarbon group or a (poly) oxyalkylene alkyl group (hereinafter collectively referred to as a hydroxyl group-containing group) that has a hydroxyl group at a terminal thereof, at least one R¹ is a hydroxyl group-containing group, a is an integer of at least 2, b is 0 or an integer, C is 0 or an integer, d is 0 or an integer, and 2 ≤ a + b + c + d ≤ 1, 000) is reacted, in the presence of component (C) and component (D), with a (meth) acrylic acid ester (B) represented by general formula (2) (in the formula, R² is a hydrogen atom or a methyl group and R³ is a substituted or unsubstituted C1–5 linear or branched monovalent hydrocarbon group), in an amount that provides a molar ratio of 1 to 10 per 1 mole of the hydroxyl groups in component (A). Component (C) is a compound indicated by general formula (3), which is liquid at 20°C, provided in an amount whereby the molar ratio is 0.001 to 0.1 per mole of the hydroxyl groups in component (A). (3) Zr (OR⁴)₄ (in the formula, R⁴ is a substituted or unsubstituted C1–10 linear or branched monovalent hydrocarbon group and may include a carbonyl group). Component (D) is a compound indicated by general formula (4) or (5), which is liquid at 20°C, provided in an amount that provides the molar ratio is 0.002 to 0.8 per mole of the hydroxyl groups in component (A) (in the formula, R⁵ and R⁶ each independently indicate a substituted or unsubstituted C1–6 monovalent hydrocarbon group) (in the formula, R⁷ indicates a substituted or unsubstituted C1–6 monovalent hydrocarbon group).

Description

Method for producing (meth)acryloyl group-containing organopolysiloxane

The present invention relates to a method for producing radically polymerizable organopolysiloxane.

The technique of applying energy to harden a liquid resin composition is a widely used technique, and is used in many fields for the production of coatings and moldings. Heat and radiation such as ultraviolet rays are used as the energy required for this curing. In the case of thermosetting, a heat-activated catalyst is added to the base resin and heat is applied to obtain a cured product. In the case of radiation curing, a composition containing a photoinitiator activated by radiation such as ultraviolet rays is cured by irradiation with radiation.

Typical functional groups used for radiation curing include (meth)acryloyl groups, mercapto groups, and epoxy groups. A (meth)acryloyl group forms a crosslink by a radical polymerization reaction, and a mercapto group undergoes an ene-thiol reaction by a radical in the presence of an alkenyl group. Epoxy groups undergo cationic polymerization with acids.

Various resins are used for such radiation curing, one of which is silicone. Silicone is a general term for organopolysiloxanes having continuous siloxane bonds as a main chain and side chains having organic groups such as methyl groups. Silicone has excellent heat resistance, cold resistance, chemical resistance, electrical insulation, mold releasability, etc., and can be made into various forms such as oil, rubber, and resin. , silicone rubber, silicone for release paper, and silicone for hard coating.

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

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

Patent Documents 2 and 3 propose a method of introducing (meth)acryloyl groups into the siloxane main chain by using hydroxyl group-containing organopolysiloxane as a raw material and subjecting (meth)acrylic acid to an esterification reaction. The problem with this technique is that the strong acid used for esterification causes not only ester bond formation but also siloxane bond cleavage, making it extremely difficult to control the reaction conditions.

In Patent Documents 4 and 5, a silane material having (meth)acryloyl groups is oligomerized by hydrolytic condensation, and then polymerized together with other silicon oligomers having dimethyl units to synthesize the desired organopolysiloxane. However, the synthesis of the silane having a (meth)acryloyl group as a raw material is complicated, and purification by distillation is required, but there is a problem that the (meth)acryloyl group tends to polymerize unless the conditions are precisely controlled.

Therefore, as a new production method, the synthesis of hydroxyl group-containing organopolysiloxane using (meth)acrylic acid ester by transesterification was investigated. Patent Documents 6 and 7 disclose a method for producing a (meth)acryloyl group-containing organopolysiloxane by transesterification using a Zr catalyst. In particular, zirconium acetylacetonate (Zr(acac) ₄ ) has been exemplified as a versatile and effective catalyst, but since it is a powdery solid, handling becomes complicated. Furthermore, since it is a solid, it has poor compatibility depending on the structure of the product, and if it disperses in the target compound without being dissolved, it may become slightly turbid and lead to deterioration of the appearance. In addition, the price of Zr(acac) ₄ is high, and a process using less expensive and versatile chemicals is desired.

Japanese Patent Publication No. 5-83570 Japanese Patent Publication No. 6-81826 Patent No. 3780113 Patent No. 2778403 Patent No. 3176010 Special table 2020-502306 WO2019/082601

As mentioned above, the transparency of the obtained (meth)acryloyl group-containing organopolysiloxane can be a problem with the conventional transesterification method, and the high cost of the catalyst used is also a bottleneck. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel transesterification method for producing a (meth)acryloyl group-containing organopolysiloxane that is transparent and has a good appearance while suppressing costs.

As a result of intensive studies to achieve the above object, the present inventors have found that an organopolysiloxane containing a hydroxyl group-containing organic group and a (meth)acrylic acid ester are combined with a zirconium alkoxide and an organic compound having a specific structure as a catalyst. We have found a new production method of obtaining a (meth)acryloyl group-containing radically polymerizable organopolysiloxane by transesterification.

That is, the present invention is a method for producing a (meth)acryloyl group-containing organopolysiloxane, comprising: (A) a hydroxyl group-containing organopolysiloxane represented by the following average formula (1);

(In the formula, R ¹ is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, or a monovalent hydrocarbon group having a terminal hydroxyl group or (poly)oxy an alkylenealkyl group (hereinafter collectively referred to as a hydroxyl group-containing group), at least one of R ¹ is a hydroxyl group-containing group, a is a positive number of 2 or more, b is 0 or a positive number, c is 0 or a positive number, d is 0 or a positive number, and 2 ≤ a + b + c + d ≤ 1,000)
(B) a (meth)acrylic acid ester represented by the following general formula (2), and

(Wherein, R ² is a hydrogen atom or a methyl group, and R ³ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 5 carbon atoms)
Provided is the production method, comprising the step of obtaining the (meth)acryloyl group-containing organopolysiloxane by reacting in the presence of the following component (C) and the following component (D).
(C) A compound which is represented by the following general formula ( ³ ₎ and is liquid at 20°C. 3)
(Wherein, R ⁴ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 10 carbon atoms, which may contain a carbonyl group)
(D) A compound represented by the following general formula (4) or (5), which is liquid at 20°C.

(wherein R ⁵ and R ⁶ are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms)

(wherein R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group of 1 to 6 carbon atoms).

In the production method of the present invention, the desired (meth)acryloyl group-containing organopolysiloxane can be efficiently obtained by transesterification using inexpensive raw materials. Moreover, since the catalyst used is liquid, it has excellent compatibility with the reaction substrate, and a product with good transparency can be obtained without remaining solid after the completion of the reaction. Furthermore, by not using a solid catalyst, the operation can be simplified because there is no complicated operation such as charging a solid into a reactor.

The details of the present invention are described below.

The present invention provides a method for producing a (meth)acryloyl group-containing organopolysiloxane. The (meth)acryloyl group-containing organopolysiloxane obtained by this production method is particularly represented by the following average formula (5).

(Wherein, R ⁸ are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, the hydroxyl group-containing group, or a group having a (meth)acryloyloxy group at the end is a valent hydrocarbon group or (poly)oxyalkylenealkyl group (hereinafter collectively referred to as a (meth)acryloyloxy group-containing group), at least one R ⁸ is the (meth)acryloyloxy group-containing group, l is a positive number of 2 or more, m is 0 or a positive number, n is 0 or a positive number, o is 0 or a positive number, 2 ≤ l + m + n + o ≤ 1,000, and a hydroxyl group-containing group is bonded The number of silicon atoms to be used is 0 to 30% with respect to the total number of all silicon atoms).

The manufacturing method of the present invention will be described in more detail below.
In the production method of the present invention, a hydroxyl group-containing organopolysiloxane represented by the following average formula (1) and

(Wherein, R ² is a hydrogen atom or a methyl group, and R ³ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 5 carbon atoms)
The production method is characterized by including a step of obtaining the (meth)acryloyl group-containing organopolysiloxane by reacting in the presence of the following component (C) and the following component (D).
(C) a compound represented by the following general formula (3), which is liquid at 20° C. Zr(OR ⁴ ) ₄ 3)
(Wherein, R ⁴ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 10 carbon atoms, which may contain a carbonyl group)
(D) A compound represented by the following general formula (4) or (5), which is liquid at 20°C.

(Wherein, R ⁵ and R ⁶ are each independently an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 6 carbon atoms)

(wherein R ⁷ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 6 carbon atoms).

In the above formula (1), R ¹ is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, or a hydroxyl group-containing group, and at least one of R ¹ is a hydroxyl-containing group. Examples of monovalent hydrocarbon groups having 1 to 10 carbon atoms include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, cycloalkyl groups such as cyclohexyl group, and aryl groups such as phenyl group and tolyl group. be done. 3,3,3-trifluoropropyl group, perfluorobutylethyl group, perfluorooctylethyl group in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms such as fluorine and chlorine group, a methoxypropyl group substituted with an alkoxy group, an ethoxypropyl group, and the like. Alkoxy groups include methoxy, ethoxy, isopropoxy, butoxy, and the like. Preferred are methyl group, ethyl group, methoxy group, ethoxy group and hydroxyl group-containing group, provided that at least one ^R1 is a hydroxyl group-containing group.

Preferably, the number of silicon atoms to which hydroxyl group-containing groups are bonded is 1 to 50%, preferably 2 to 45%, more preferably 3 to 40% of the total number of all silicon atoms. is good. If the number of silicon atoms to which the hydroxyl group-containing group is bonded is less than the above lower limit, the radiation curability may be insufficient. On the other hand, if it is more than the above upper limit, the substrate concentration of (meth)acrylic acid in the reaction system becomes high during the reaction, and there is a possibility that viscosity increase or gelation may occur due to polymerization of (meth)acryloyl groups.

The monovalent hydrocarbon group having a terminal hydroxyl group is preferably a monovalent hydrocarbon group having 2 to 20 carbon atoms, more preferably 3 to 15 carbon atoms and having one terminal hydroxyl group. More preferably, it is a monovalent hydrocarbon group having 2 to 10 carbon atoms, preferably 3 to 6 carbon atoms, and having one terminal hydroxyl group. A (poly)oxyalkylenealkyl group having a terminal hydroxyl group is a (poly)oxyalkylenealkyl group having one terminal hydroxyl group, preferably having 4 to 25 carbon atoms, more preferably 5 to 16 carbon atoms. Examples of the oxyalkylene group include an oxyethylene group, an oxyisopropylene group, an oxy n-propylene group, and an oxybutylene group. Among them, an oxyethylene group and an oxyisopropylene group are preferred, and two or more oxyalkylene groups are used. may have. Examples of the hydroxyl group-containing group are represented by the following structures. In the formula below, the points indicated by dotted lines are bonds with the silicon atoms of the organopolysiloxane.

^R2 is a hydrogen atom or a methyl group. e is an integer of 1-10, and f and g are each independently an integer of 1-5. Preferably, e is an integer from 1 to 7 and f and g are independently from each other integers from 1 to 3. More preferably, e is an integer from 1 to 4, and f and g are 1 or 2 independently of each other. In the above formula, the bonding order of ethylene oxide and propylene oxide shown in parentheses is not limited, and they may be arranged randomly or form a block structure. In the formula, broken lines indicate bonds with silicon atoms of organopolysiloxane. If the proportion of hydroxyl groups in the composition as a whole satisfies the above range, it may contain a compound having both a hydroxyl group-containing organic group and a (meth)acryloyl group, as shown in the above figure.

In the average formula (1), a is a positive number of 2 or more, b is 0 or a positive number, c is 0 or a positive number, and d is 0 or a positive number, provided that 2 ≤ a + b + c + d ≤ 1 , 000. Preferably, the amount of hydroxyl group-containing groups satisfies the above range, and the organopolysiloxane has a viscosity at 25° C. of 5 to 10,000 mPa·s, more preferably 10 to 5,000 mPa·s. Just do it. Viscosity is a value measured with a BM type rotational viscometer. The upper limits of a, b, c, and d may be any value that satisfies 2≤a+b+c+d≤1,000 and the organopolysiloxane has the viscosity described above. The upper limit of b is preferably 998 or less, more preferably 798 or less, and even more preferably 598 or less. Although the lower limit of b may be 0, b is preferably 1 or more, more preferably 5 or more, and still more preferably 8 or more. That is, preferably 1≦b≦998, more preferably 5≦b≦798, and even more preferably 8≦b≦598. c is preferably 0≤c≤5, more preferably 0≤c≤4, and still more preferably 0≤c≤3. d is preferably 0≦d≦4, more preferably 0≦d≦3, and still more preferably 0≦d≦2. The organopolysiloxane represented by the average formula (1) more preferably has a linear structure.

Examples of the organopolysiloxane represented by the average formula (1) include compounds represented by the following structures. In the formula, Me represents a methyl group and Ph represents a phenyl group.

(Wherein, h is an integer of 0 to 1,000, i is an integer of 0 to 800, j is an integer of 1 to 200, and k is an integer of 0 to 100. Preferably, the above is a number that satisfies 0≦b≦998, more preferably a number that satisfies 1≦b≦998, more preferably a number that satisfies 5≦b≦798, and still more preferably a number that satisfies 8≦b≦598 .)

[(B) component]
Component (B) is a (meth)acrylic acid ester represented by the following general formula (2), and is a reaction agent for introducing a (meth)acryloyl group into component (A).

In formula (2), ^R2 is a hydrogen atom or a methyl group. R ³ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 5 carbon atoms. Examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, butyl group and pentyl group. From the viewpoints of industrial cost and progress of transesterification reaction, R ³ is preferably an alkyl group having 1 to 4 carbon atoms, that is, a methyl group, an ethyl group, a propyl group or a butyl group. On the other hand, if R ³ has more than 5 carbon atoms, the boiling point of the alcohol produced during the transesterification reaction becomes high, making it difficult to remove it from the reaction system, making it difficult for the transesterification reaction to proceed.

The amount of component (B) is 1 to 10 mol, preferably 1.5 to 9 mol, more preferably 2 to 8 mol, relative to 1 mol of hydroxyl groups in organopolysiloxane (A). It is better to react. If the amount of component (B) is less than the above lower limit, the rate of introduction of (meth)acryloyl groups by transesterification will decrease. If it is more than the above upper limit, the rate of introduction of (meth)acryloyl groups by transesterification is high, but the amount of component (B) blended is too large, resulting in a decrease in pot yield.

[(C) component]
Component (C) is represented by the following general formula (3) and is a compound that is liquid at 20°C.
Zr(OR ⁴ ) ₄ (3)
(Wherein, R ⁴ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon having 1 to 10 carbon atoms, which may contain a carbonyl group)

R ⁴ is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, which may contain a carbonyl group in its structure. Examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, isopropyl group and t-butyl group, cycloalkyl groups such as cyclohexyl group, phenyl group and acetyl group. A monovalent hydrocarbon group containing a carbonyl group includes an acetyl group and a (meth)acryloyl group. Alternatively, some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with halogen atoms or other groups, exemplified by trifluoromethyl group, 3,3,3-trifluoropropyl group and the like. be. Component (C) is particularly preferably a zirconium alkoxide having an alkyl group of 1 to 6 carbon atoms as R ⁴ , and from the viewpoint of general availability, R ⁴ is preferably a propyl group or a butyl group.

The component (C) is the main component of the catalyst for reacting the components (A) and (B). The amount of component (C) is 0.001 to 0.1 mol, preferably 0.003 to 0.08 mol, more preferably 0.005 to 0.05, per 1 mol of hydroxyl groups contained in component (A). Mole. If it is less than the above lower limit, the reaction may not proceed sufficiently. If it exceeds the above upper limit, it may become difficult to remove after the reaction.

The component (C) is liquid at 20°C. Since the component (C) is a liquid catalyst, it can be charged into the reaction vessel in the same manner as liquid compounds such as the components (A) and (B). If the catalyst is a solid, it is necessary to take measures to handle dust, which may complicate the operation. Moreover, in the case of a solid catalyst, since the compatibility varies depending on the structure of the product, the catalyst may not dissolve in the product but may be dispersed as a solid, making the product turbid.

[(D) Component]
Component (D) is a compound represented by the following general formula (4) or (5) and liquid at 20°C.

(wherein R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group of 1 to 6 carbon atoms)

R ⁵ is an unsubstituted or substituted monovalent hydrocarbon group of 1 to 6 carbon atoms. Examples thereof include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, cycloalkyl groups such as cyclohexyl group, and phenyl group. It is preferably a linear or branched monovalent hydrocarbon group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. ⁵ is preferably a methyl group. Alternatively, some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with halogen atoms or other groups, exemplified by trifluoromethyl group, 3,3,3-trifluoropropyl group and the like. be.

R ⁶ is an unsubstituted or substituted monovalent hydrocarbon group of 1 to 6 carbon atoms. Examples thereof include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, cycloalkyl groups such as cyclohexyl group, and phenyl group. It is preferably a linear or branched monovalent hydrocarbon group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. ⁶ is preferably a methyl group and an ethyl group. Alternatively, some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with halogen atoms or other groups, exemplified by trifluoromethyl group, 3,3,3-trifluoropropyl group and the like. be.

Among the components (D), compounds represented by the general formula (4) include, for example, methyl acetoacetate, ethyl acetoacetate, and propyl acetoacetate. Methyl acetoacetate and ethyl acetoacetate are preferred because of their general availability.

R ⁷ is an unsubstituted or substituted monovalent hydrocarbon group of 1 to 6 carbon atoms. Examples thereof include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, cycloalkyl groups such as cyclohexyl group, and phenyl group. It is preferably a linear or branched monovalent hydrocarbon group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. ⁷ is preferably a methyl group or an ethyl group. Alternatively, some or all of the hydrogen atoms bonded to these carbon atoms may be substituted with halogen atoms or other groups, exemplified by trifluoromethyl group, 3,3,3-trifluoropropyl group and the like. be.

Among the (D) components, the compound represented by the general formula (5) includes, for example, acetylacetone.

The component (D) is a component that functions in concert with the main component (C) of the catalyst for reacting the components (A) and (B). It is considered that the component (D) is coordinated with the component (C) to form a catalyst species that effectively works for transesterification in the present invention. The amount of component (D) is such that the molar ratio of component (A) to 1 mol of hydroxyl groups is 0.002 to 0.8 mol, preferably 0.005 to 0.5 mol, more preferably 0.005 to 0.5 mol. 01 to 0.4 mol. If it is less than the above lower limit, the reaction may not proceed sufficiently. If the above upper limit is exceeded, the component (D) itself may act as a substrate for the transesterification reaction, causing side reactions.

[(E) component]
The component (E) is a polymerization inhibitor, and is an additive for suppressing the polymerization of the (meth)acrylic acid ester as the component (B) without reacting with the component (A) during the reaction. The polymerization inhibitor is not limited as long as it has the effect of suppressing radical polymerization, and the following alkylphenols are available.

p-methoxyphenol, 2,6-di-t-butylhydroxytoluene, 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-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), 2,2'-thio-bis(4-methyl-6-t-butylphenol).

In addition, amine-based polymerization inhibitors can also be used, including the following. Alkylated diphenylamine, 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 the polymerization inhibitor is 0.01 to 1 part by mass, preferably 0.02 to 0.5 part by mass, more preferably 0.03 to 0.3 part by mass, per 100 parts by mass of component (A). department is good. If it is more than the above upper limit, the curability of the obtained radiation-curable organopolysiloxane composition containing the radically polymerizable organopolysiloxane may be lowered. If it is less than the above lower limit, there is a concern that (meth)acrylic acid may polymerize and thicken or gel during production.

[solvent]
The transesterification reaction of the present invention can be carried out without solvent or in an organic solvent. Examples of organic solvents include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, heptane, octane, isooctane, cyclohexane, methylcyclohexane, and isoparaffin, industrial gasoline, petroleum benzine, and hydrocarbon solvents such as solvent naphtha; ether solvents such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane, and 1,4-dioxane; and mixed solvents thereof. . These can be used individually by 1 type or in combination of 2 or more types as appropriate.

[Transesterification reaction]
In the present invention, the hydroxyl groups contained in component (A) and the alkyl ester sites of component (B) are transesterified by the catalyst components (C) and (D) to obtain the desired organopolysiloxane. be. A schematic of the reaction is shown below. Siloxane-OH in the formula is a hydroxyl group-containing organopolysiloxane represented by the above formula (1), and includes the compounds exemplified for the above component (A).

More specifically, the reaction temperature can be 70 to 150°C, preferably 75 to 145°C, more preferably 80 to 140°C. If it is lower than 70°C, the reaction may not proceed sufficiently because the by-product alcohol may not sufficiently escape from the reaction system, and if it is higher than 150°C, the (B) component (meth)acrylate There is concern about thickening and gelation due to polymerization of 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. The amount of oxygen at this time is 0.1 to 20%, preferably 0.5 to 18%, more preferably 1 to 15% in terms of volume.

After completion of the reaction, the product can be obtained by distilling off the remaining component (B) under reduced pressure. The temperature during distillation may be from 20° C. to 120° C., and the reduced pressure may be from 1 to 200 mmHg, but is not limited thereto.
As described above, the (meth)acryloyl group-containing organopolysiloxane obtained in the present invention is represented by the following average formula (5).

In the formula, R ⁸ is the group defined by R ¹ in the average formula (1) above, or a monovalent hydrocarbon group or (poly)oxyalkylene group having a (meth)acryloyl group at the end (hereinafter collectively referred to as (meth) (referred to as an acryloyloxy group-containing group). At least one of ^R8 is a (meth)acryloyloxy group-containing group. Preferably, the number of silicon atoms to which the (meth)acryloyloxy group-containing group is bonded is 1 to 50%, more preferably 2 to 45%, and still more preferably 3 to 40% of the total number of all silicon atoms. is good.

The (meth)acryloyloxy group-containing group is a group in which the terminal hydroxyl group of the hydroxyl group-containing group described above is substituted with a (meth)acryloyloxy group. Therefore, unlike a group into which a (meth)acryloyloxy group is introduced by ring opening of an epoxy group, it does not have a hydroxyl group. Preferably, a monovalent hydrocarbon group having 2 to 10 carbon atoms, preferably 3 to 6 carbon atoms, having one (meth)acryloyloxy group at the end, or having one (meth)acryloyloxy group at the end , a (poly)oxyalkylenealkyl group having 4 to 25 carbon atoms, preferably 5 to 16 carbon atoms. Examples of the oxyalkylene group are as described above, preferably an oxyethylene group and an oxyisopropylene group, and may have two or more oxyalkylene groups. For example, it is represented by the following structure. In the formula below, the points indicated by the dotted lines are the bonds with the silicon atoms of the polysiloxane.

^R2 is a hydrogen atom or a methyl group. e is an integer of 1-10, and f and g are each independently an integer of 1-5. Preferably, e is an integer from 1 to 7 and f and g are independently from each other integers from 1 to 3. More preferably, e is an integer from 1 to 4, and f and g are 1 or 2 independently of each other. In the above formula, the bonding order of ethylene oxide and propylene oxide shown in parentheses is not limited, and they may be arranged randomly or form a block structure. In the formula, broken lines indicate bonds with silicon atoms of organopolysiloxane.

In the average formula (5), l is a positive number of 2 or more, m is 0 or a positive number, n is 0 or a positive number, o is 0 or a positive number, 2 ≤ l + m + n + o ≤ 1, 000. Preferably, the amount of the (meth)acryloyloxy group-containing organic group satisfies the above range, and the organopolysiloxane has a viscosity at 25° C. of 5 to 10,000 mPa·s, more preferably 10 to 5,000 mPa·s. It should be a value that has The (meth)acryloyl group-containing organopolysiloxane obtained by the production method of the present invention can have a low viscosity. Preferably 5 to 3,000 mPa s, more preferably 5 to 2,000 mPa s, still more preferably 8 to 1,500 mPa s, further 10 to 1,000 mPa s, particularly 15 to 700 mPa s. can have The viscosity is a value measured by a BM type rotational viscometer.
The upper limits of l, m, n, and o may be any value that satisfies 2≦l+m+n+o≦1,000 and the organopolysiloxane has the viscosity described above. The upper limit of m is preferably 998 or less, more preferably 798 or less, and even more preferably 598 or less. Although the lower limit of m may be 0, m is preferably 1 or more, more preferably 5 or more, and still more preferably 8 or more. That is, preferably 1≦m≦998, more preferably 5≦m≦798, and even more preferably 8≦m≦598. n is preferably 0≦n≦5, more preferably 0≦n≦4, and still more preferably 0≦n≦3. o is preferably 0≦o≦4, more preferably 0≦o≦3, and still more preferably 0≦o≦2. The organopolysiloxane represented by the average formula (5) more preferably has a linear structure.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.
In the following, physical properties in the tables were measured by the following test methods.
In addition, the part in an example is a mass part.

[(Meth)acryloyl group introduction rate]
The (meth)acryloyl group introduction rate of the transesterification reaction in Examples or Comparative Examples was calculated as follows. The rate of introduction of (meth)acryloyl groups by the esterification reaction of the present invention was determined by using ¹ H-NMR. Since (δ=0.42) is unchanged before and after the reaction, this proton peak was used as a reference. For example, in the case of an acryloyl group, if the integrated value of the standard methylene proton peak is 1.00 and the rate of introduction of the acryloyl group by the esterification reaction is 100%, each of the three protons of the acryloyl group The proton peak integral value is 0.50. From this, the acryloyl group introduction rate is determined by the following formula.

Acryloyl group introduction rate = [(average of integrated value of three proton peaks of acryloyl group)/0.50] x 100 (%)

[Example 1]
72.91 g of organopolysiloxane represented by the following average formula (A-1), (B-1) ethyl acrylate 47.09 g (the organo 3 moles per 1 mole of hydroxyl groups in polysiloxane (A-1)), 0.18 g of 2,2′-methylenebis(6-tert-butyl-4-methylphenol) monoacrylate as a polymerization inhibitor, (C-1) 0.902 g of an 80% butanol solution of zirconium tetrabutoxide (liquid at 20° C.) (an amount of 0.012 mol per 1 mol of hydroxyl groups in the organopolysiloxane (A-1)), ( D-1) 0.979 g of ethyl acetoacetate (liquid at 20° C.) (an amount of 0.048 mol per 1 mol of hydroxyl groups in the organopolysiloxane (A-1)) was charged, and the reaction system was adjusted to 85 °C, the reaction was carried out by heating and stirring for 24 hours while distilling off by-product ethanol by nitrogen flow. The unreacted components were removed from the reaction solution by distillation under reduced pressure of 20 mmHg at 85° C. for 2 hours to obtain an organopolysiloxane represented by the following average formula (X-1). The target product was yellow and transparent, and the acryloyl group introduction rate was 98%.

[Example 2]
72.91 g of organopolysiloxane represented by the following average formula (A-2), (B-1) ethyl acrylate 47.09 g (the organo 3 mol per 1 mol of hydroxyl groups in polysiloxane (A-1)), 0.18 g of 2,2′-methylenebis(6-tert-butyl-4-methylphenol) monoacrylate as a polymerization inhibitor, (C-1) 1.503 g of an 80% butanol solution of zirconium tetrabutoxide (liquid at 20° C.) (an amount of 0.02 mol per 1 mol of hydroxyl groups in the organopolysiloxane (A-2)), ( D-1) 1.632 g of ethyl acetoacetate (liquid at 20°C) (0.08 mol per 1 mol of hydroxyl groups in the organopolysiloxane (A-2)) was charged, and the reaction system was heated to 85°C. The mixture was heated and stirred for 24 hours while distilling off ethanol produced as a by-product at a temperature at which the mixture was reacted. Unreacted components were removed from the reaction solution by distillation under reduced pressure of 20 mmHg at 85° C. for 2 hours to obtain a yellow transparent product. The product was an organopolysiloxane represented by the following average formula (X-2). The acryloyl group introduction rate was 98%.

[Example 3]
In place of (D-1) ethyl acetoacetate in Example 2 above, 1.456 g (D-2) methyl acetoacetate (liquid at 20° C.) (per mole of hydroxyl groups in the organopolysiloxane (A-2) Example 2 was repeated with the exception that 0.08 mol was used to obtain a yellow transparent desired product. The acryloyl group introduction rate was 96%.

[Example 4]
Instead of (C-1) the 80% butanol solution of zirconium tetrabutoxide in Example 2 above, 3.668 g of (C-2) a 70% propanol solution of zirconium tetrapropoxide (liquid at 20 ° C.) (the organopoly 0.05 mol per 1 mol of hydroxyl groups in the siloxane (A-2)), and the amount of (D-1) ethyl acetoacetate is 4.080 g (the amount of the organopolysiloxane (A-2) Example 2 was repeated except that the amount was adjusted to 0.2 mol per 1 mol of hydroxyl group to obtain a yellow transparent desired product. The acryloyl group introduction rate was 98%.

[Example 5]
1.256 g of (D-3) acetylacetone in place of (D-1) ethyl acetoacetate in Example 2 (0.08 mol per 1 mol of hydroxyl groups in the organopolysiloxane (A-2)) Example 2 was repeated except that was used to obtain a yellow transparent object. The acryloyl group introduction rate was 98%.

[Comparative Example 1]
Example 1 was repeated except that (D-1) ethyl acetoacetate was not used in Example 1 to obtain a yellow transparent desired product. The acryloyl group introduction rate was 19%.

[Comparative Example 2]
Example 1 was repeated except that (C-1) 80% butanol solution of zirconium tetrabutoxide was not used in Example 1 to obtain a yellow transparent target product. The acryloyl group introduction rate was 5%.

[Comparative Example 3]
(C-1) 0.902 g of an 80% butanol solution of zirconium tetrabutoxide in Example 1 (an amount of 0.012 mol per 1 mol of hydroxyl groups in the organopolysiloxane (A-1)), and (D-1) 0.764 g of zirconium acetylacetonate (Zr(acac) _4, melting point 191°C) instead of ethyl acetoacetate (0.01 per mole of hydroxyl group in the organopolysiloxane (A-1)) Example 1 was repeated, except that molar amounts were used. The resulting product was a slightly turbid yellow solution with solids derived from Zr(acac) ₄ remaining. The acryloyl group introduction rate was 98%.

[Comparative Example 4]
In Example 2, (C-1) 0.902 g of an 80% butanol solution of zirconium tetrabutoxide (an amount equivalent to 0.012 equivalents to the hydroxyl groups in the organopolysiloxane (A-1)) was used, and (D -1) 0.764 g of zirconium acetylacetonate (Zr(acac) ₄ , melting point 191° C.) instead of ethyl acetoacetate (0.01 mol per 1 mol of hydroxyl group in the organopolysiloxane (A-1)); Example 2 was repeated to obtain a yellow, transparent target product, except that a different amount was used. The acryloyl group introduction rate was 99%.

Since the catalyst (Zr(acac) ₄ ) used in Comparative Examples 3 and 4 is powder, the operation may be complicated. For example, there is a problem that the powder must be charged directly into the opening/closing type introduction part instead of being charged from the supply line by pressure feeding, which makes the operation time-consuming.

According to the production method of the present invention, since inexpensive raw materials are used and the operation is simple, it is possible to efficiently obtain the desired organopolysiloxane. In addition, since a liquid catalyst is used, it is possible to improve appearance defects due to undissolved solid catalyst. The obtained (meth)acryloyl-modified organopolysiloxane can be used for radiation-curable coating agents, additives, resins, and the like.

Claims

A method for producing a (meth)acryloyl group-containing organopolysiloxane,
(A) a hydroxyl group-containing organopolysiloxane represented by the following average formula (1);

(In the formula, R 1 is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, or a monovalent hydrocarbon group having a terminal hydroxyl group or (poly)oxy an alkylenealkyl group (hereinafter collectively referred to as a hydroxyl group-containing group), at least one of R 1 is a hydroxyl group-containing group, a is a positive number of 2 or more, b is 0 or a positive number, c is 0 or a positive number, d is 0 or a positive number, and 2 ≤ a + b + c + d ≤ 1,000)
(B) a (meth)acrylic acid ester represented by the following general formula (2), and

(Wherein, R 2 is a hydrogen atom or a methyl group, and R 3 is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 5 carbon atoms)
(C) the following general formula (3 ) and is liquid at 20° C. Amount Zr(OR 4 ) 4 (3) that gives a molar ratio of 0.001 to 0.1 to 1 mol of hydroxyl groups in component (A)
(Wherein, R 4 is an unsubstituted or substituted, linear or branched monovalent hydrocarbon group having 1 to 10 carbon atoms, which may contain a carbonyl group)
(D) A compound represented by the following general formula (4) or (5), which is liquid at 20°C.

(wherein R 5 and R 6 are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms)

(wherein R 7 is an unsubstituted or substituted monovalent hydrocarbon group of 1 to 6 carbon atoms).
The production method according to claim 1, wherein the number of silicon atoms to which the hydroxyl group-containing groups in component (A) are bonded is 1 to 50% of the total number of silicon atoms.
3. The production method according to claim 1, wherein component (C) is a zirconium alkoxide having an alkyl group of 1 to 6 carbon atoms as R4 .
The production method according to any one of claims 1 to 3, wherein (E) a polymerization inhibitor is added in an amount of 0.01 to 1 part by mass per 100 parts by mass of component (A) in said step.
In the above step, the components (A) to (D) and optionally the component (E) are mixed and stirred in a reaction vessel, and the mixture in the reaction vessel is heated to 70 to 150 ° C., 5. The production method according to any one of claims 1 to 4, wherein the components (A) and (B) are reacted while the by-produced alcohol is removed from the reaction vessel.
The production method according to any one of claims 1 to 5, wherein the (meth)acryloyl group-containing organopolysiloxane is represented by the following average formula (5).

(Wherein, R 8 are each independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group, the hydroxyl group-containing group, or a group having a (meth)acryloyloxy group at the end is a valent hydrocarbon group or (poly)oxyalkylenealkyl group (hereinafter collectively referred to as a (meth)acryloyloxy group-containing group), at least one R 8 is the (meth)acryloyloxy group-containing group, l is a positive number of 2 or more, m is 0 or a positive number, n is 0 or a positive number, o is 0 or a positive number, 2 ≤ l + m + n + o ≤ 1,000, and a hydroxyl group-containing group is bonded The number of silicon atoms to be used is 0 to 30% with respect to the total number of all silicon atoms)