JP2551306B2 - Method for producing silicone-based graft polymer having excellent storage stability - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a silicone-based graft polymer having excellent storage stability. The silicone-based graft polymer is preferably used as a paint base material or a coating agent.

[0002]

2. Description of the Related Art Polydimethylsiloxane having silanol groups at both ends of a molecule and alkoxy having an unsaturated double bond such as .gamma.-methacryloyloxypropyltrimethoxysilane are known as one of the methods for producing a silicone-based graft polymer. There is known a method of using a radically polymerizable silicone compound obtained by reacting a silane compound in an approximately equimolar amount or in an excess molar ratio of the alkoxysilane compound (for example, Japanese Patent Publication No. 1-6016).
No. 2, etc.). In the above method, the radical polymerizable silicone compound is copolymerized with another low molecular weight vinyl monomer to obtain a graft polymer having the silicone compound as a branch component.

In the synthesis of the radically polymerizable silicone compound in the above method for producing a silicone graft polymer, a readily available trialkoxysilane compound is usually used as an alkoxysilane compound to be reacted with silicone such as polydimethylsiloxane. The alkoxysilane compound has three reactive groups Si-X in one molecule.
When it is reacted with polydimethylsiloxane in the molar ratio as described above to have the same, a hydrolyzable alkoxy group bonded to a silicon atom remains in the obtained radically polymerizable silicone compound. As a result, the resulting silicone-based graft polymer also contains a hydrolyzable alkoxy group bonded to a silicon atom, and when the graft polymer is in contact with air for a long time, the moisture in the air reacts with the alkoxy group to cause gelation. In the case of the above method, a silicone-based graft polymer having excellent storage stability has not been obtained.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have completed the present invention. That is, the present invention relates to the following compound (A) 1
A silicone compound obtained by subjecting the following compound (B) to a condensation reaction in a ratio of 0.8 to 3 mol per mol, and a monomer mixture comprising an acidic or basic vinyl monomer and other vinyl monomers. Is a radical copolymerized in the presence of the following compound (C), which is a method for producing a silicone-based graft polymer having excellent storage stability. Compound (A): a compound represented by Chemical Formula 4

Embedded image (In the formula, n is a positive number of 10 to 600, and R ¹ and R ² are alkyl groups or phenyl groups having 1 to 10 carbon atoms.) Compound (B): compound represented by Chemical formula 5

Embedded image (In the formula, R ³ is a hydrogen atom or a methyl group, R is an alkyl group having 1 to 10 carbon atoms or a phenyl group, X is an alkoxy group having 1 to 10 carbon atoms or a halogen atom, and p is Is 0 or 1) Compound (C): Compound represented by Chemical formula 6

[Chemical 6] (R ⁴ , R ⁵ and R ⁶ are monovalent saturated hydrocarbon groups having 1 to 10 carbon atoms or a phenyl group, and R ⁷ is a methyl group or an ethyl group)

The present invention will be described in more detail below. As described above, the silicone compound in the present invention is obtained by subjecting the compound (A) (hereinafter referred to as terminal hydroxypolysiloxane) and the compound (B) (hereinafter referred to as unsaturated bond-containing silane) to a condensation reaction.
The terminal hydroxypolysiloxane in the present invention is a polysiloxane having a condensation degree n of siloxane units of 100 to 600, and more preferably n of 200 to 500. When n is less than 100, in the reaction between the terminal hydroxypolysiloxane and the unsaturated bond-containing silane,
When radically polymerizing a silicone compound obtained by using a larger amount of unsaturated bond-containing silane than the reaction ratio of 1: 1 with other monomers, gelation is likely to occur. Examples of the monovalent saturated hydrocarbon group in the terminal hydroxypolysiloxane include a methyl group, an ethyl group, and a decyl group. Of the monovalent saturated hydrocarbon groups and phenyl groups, a methyl group is particularly preferred.

Specific examples of unsaturated bond-containing silanes include:
γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane, γ- (meth) acryloyloxypropylmethyldimethoxysilane, γ- (meth) acryloyloxypropylmethyldiethoxysilane, 3 -(2-
Examples thereof include (meth) acryloyloxyethoxy) propyltrimethoxysilane and 3- (2- (meth) acryloyloxyethoxy) propylmethyldimethoxysilane, and preferably γ- (meth) acryloyloxypropyltrimethoxysilane and γ- ( (Meth) acryloyloxypropylmethyldimethoxysilane.

The preferred reaction ratio between the terminal hydroxypolysiloxane and the unsaturated bond-containing silane is such that when γ- (meth) acryloyloxypropyltrialkoxysilane is used as the unsaturated bond-containing silane, it is Saturated bond-containing silane 0.8
To 3 mol, more preferably the above polysiloxane 1
It is 1.3 to 3 moles of the unsaturated bond-containing silane per mole. Further, as an unsaturated bond-containing silane, γ- (meth)
When acryloyloxypropylalkyldialkoxysilane is used, the amount of the unsaturated bond-containing silane is 1.5 to 3 mol per mol of the terminal hydroxypolysiloxane.

When the reaction molar ratio is less than 0.8 mol of unsaturated bond-containing silane per 1 mol of the polysiloxane,
Since the resulting radical-polymerizable silicone contains a large amount of polysiloxane with no radical-polymerizable group bonded, when a silicone-based graft polymer obtained from this as a raw material is used as a coating agent, unreacted polysiloxane is not applied to the coated surface. And the physical properties of the coating film are inferior. On the other hand, when the amount of the unsaturated bond-containing silane exceeds 3 mols, the viscosity of the obtained silicone-based graft polymer remarkably increases, and when the graft polymer is used as a coating agent, the leveling property is poor.

The condensation reaction of the above two components is carried out in an organic solvent. Preferred organic solvents include diethyl ether,
Tetrahydrofuran, acetone, methyl ethyl ketone,
Methyl isobutyl ketone, toluene, xylene, ethyl acetate, butyl acetate, hexane, heptane, petroleum ether, mineral spirits and the like can be mentioned.

The condensation reaction can be carried out without a catalyst, but it is preferable to use a compound such as sulfuric acid, p-toluenesulfonic acid, sodium hydroxide, potassium hydroxide, potassium acetate and dibutyltin dilaurate as a catalyst. A particularly preferred catalyst is p-toluenesulfonic acid, and its amount is preferably about 0.01 to 5% by weight based on the total amount of polysiloxane and unsaturated bond-containing silane. The reaction temperature is usually 50 to 150 ° C., and the reaction time is 1 to 20 hours.

In the present invention, the silicone compound obtained by the above method and the monomer described below are copolymerized in the presence of the compound (C) in an organic solvent. During the copolymerization process, the compound (C) reacts with the active group Si-X (X is an alkoxy group or a halogen atom) remaining in the silicone compound, and the resulting silicone-based graft polymer has excellent storage stability. It has a nature. Specific examples of the compound (C) include trimethylmethoxysilane,
Examples thereof include triethylmethoxysilane, trimethylethoxysilane, dimethylphenylmethoxysilane, dimethylphenylethoxysilane and triphenylmethoxysilane, with trimethylmethoxysilane being preferred. A trialkylalkoxysilane having an alkoxy group having a carbon number of 3 or more such as a propoxy group or a butoxy group as a constituent component is inferior in reactivity to the Si-X bond,
When these are used, a silicone-based graft polymer having excellent storage stability cannot be obtained.

When a trialkylsilanol or a trialkylhalogenosilane is used, the reaction of condensing two molecules between the trialkylsilanols or between the trialkylhalogenosilanes is prioritized.
The silicone-based graft polymer cannot be effectively stabilized.

The monomer to be copolymerized with the silicone compound is a monomer mixture consisting of an acidic or basic vinyl monomer and another vinyl monomer, and the acidic or basic vinyl monomer is a compound ( It acts as a catalyst for the reaction between C) and the aforementioned group Si—X in the silicone compound. Examples of the acidic vinyl monomer include (meth) acrylic acid, maleic anhydride, crotonic acid, itaconic acid, citraconic acid, isocrotonic acid, 2-acrylamido-2-methanesulfonic acid and acid phosphooxyethyl (meth) acrylate. As the basic vinyl monomer,
Examples thereof include dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl (meth) acrylamide.

Vinyl monomers other than acidic or basic vinyl monomers include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. (Meta)
Alkyl acrylate; acrylamide, hydroxyalkyl (meth) acrylate, styrene, acrylonitrile and perfluoroalkyl (meth) acrylate. A preferable ratio of the acidic or basic vinyl monomer in the monomer to be copolymerized with the silicone compound is 1 to 20% by weight, more preferably 2 to 20% by weight. If the amount of the acidic or basic vinyl monomer is less than 1% by weight, the reaction between the compound (C) and the group Si-X in the silicone compound does not proceed smoothly, and the obtained silicone-based graft polymer is stable in storage. Inferior in sex.

The copolymerization ratio of the silicone compound and the copolymerization monomer is preferably 5 to 60% by weight of the silicone compound and 95 to 40% by weight of the copolymerization monomer. When the amount of the silicone compound is less than 5% by weight, when the obtained silicone-based graft polymer is coated on the substrate, the silicone properties are hardly exhibited in the coating film. On the other hand, if it exceeds 60% by weight, the adhesion to the substrate is poor.

In radical copolymerization of a silicone compound and a copolymerizable monomer, for example, Japanese Patent Laid-Open No. 1520222/1983 is adopted.
The polymerization methods described in JP-A No. 60-123518 and JP-A No. 60-123518 can be employed. The radical polymerization initiator is preferably an azo compound, specifically, azobisisobutyronitrile (hereinafter referred to as AIBN), azobis (2,4-dimethylvaleronitrile), azobis (2-
Methyl butyronitrile) and azobis (cyclohexane-1-carbonitrile). The amount of the polymerization initiator used is generally 0.01 with respect to the total weight of the polymerizable components.
˜5 wt%, preferably 0.1 to 2 wt%. The radical copolymerization temperature is 50 to 15
0 degreeC is preferable, More preferably, it is 60-100 degreeC. The polymerization time is usually 5 to 25 hours.

In the above copolymerization, the preferred amount of the compound (C) added to the polymerization system is used in the synthesis of the silicone compound when the total amount of the silicone compound synthesized by the above method is used for the copolymerization. It is selected according to the type and amount of the unsaturated double bond-containing silane.
When the unsaturated double bond-containing silane is a compound having two substituents X per molecule, the compound (C) may be used in an amount of 1 mol or more per 1 mol of the unsaturated double bond-containing silane used. Preferably, it is more preferably 1.5 to 3 mol. When the amount of the compound (C) with respect to the unsaturated double bond-containing silane is less than 1, the storage stability of the graft polymer solution is poor.

When the unsaturated double bond-containing silane is a compound having three substituents X per molecule, the silane 1
It is preferable to use the compound (C) in an amount of 1.5 mol or more, and more preferably 2.3 to 4.5 mol per mol.
In this case, if the amount of the compound (C) used is less than 1.5 mol, the storage stability of the graft polymer solution will be poor. When a part of the synthesized silicone compound is subjected to copolymerization, the amount of the compound (C) can be set on the same basis as above depending on the ratio of the silicone compound added to the copolymerization.
As a method of adding the compound (C) to the polymerization system, it is preferable to add it to the polymerization system together with other components before the initiation of the polymerization.

The present invention will be described more specifically below with reference to Reference Examples, Examples and Comparative Examples. Reference Examples 1 to 4 (Synthesis of Silicone Compound) In a flask equipped with a stirrer, a condenser, and a thermometer, 111 g (5 mmol) of α, ω-disidroxypolydimethylsiloxane having a condensation degree n of siloxane units of 300, p-toluenesulfonic acid 0.1
2 g, 74 g of toluene and 37 g of methyl ethyl ketone (hereinafter abbreviated as MEK) were charged, and the following amounts of γ-methacryloyloxypropyltrimethoxysilane were added.

Reference Example 1: 2.07 g (8.35 mmol) Reference Example 2: 2.48 g (10.0 mmol) Reference Example 3: 3.31 g (13.6 mmol) Then, the above mixed solution was heated. The temperature was maintained at 70 ° C for 3 hours. After cooling, 30 g of a basic anion exchange resin was added to the obtained reaction liquid, and the mixture was stirred at 40 ° C. for 2 hours to adsorb p-toluenesulfonic acid used as a catalyst. The anion exchange resin was removed by filtration to obtain a colorless and transparent solution containing the reaction product silicone compound.

[0021]

Examples 1 to 3 Refer to Reference Examples 1 to 3 on a Frafuco equipped with a stirrer, a condenser, a thermometer, a dropping funnel, and a nitrogen introducing tube.
The total amount of the silicone compound solution synthesized in (110 g as a silicone compound), 650 g of MEK solvent, 240 g of methyl methacrylate, 40 g of methacrylic acid, 3.23 g (31.1 mmol) of trimethylmethoxysilane and AI.
After charging 4 g of BN, the temperature was maintained at 75 ° C. for 7 hours under a nitrogen atmosphere to obtain a graft polymer solution.

With respect to the obtained reaction liquid, the initial solution viscosity (25 ° C.) and the solution viscosity after holding at 60 ° C. for 1 month (25 ° C.) were measured, and the following results were obtained. Example 1 (using the silicone compound of Reference Example 1); initial stage
1,230 cps, after 1 month at 60 ° C. 1,250 cps Example 2 (using the silicone compound of Reference Example 2);
1,290 cps, after 1 month at 60 ° C. 1,320 cps Example 3 (using the silicone compound of Reference Example 3);
1,260 cps, after 1 month at 60 ℃ 1,270 cps

[0023]

Comparative Example 1 With respect to the silicone-based graft polymer solution obtained by the same polymerization operation as in Example 1 except that trimethylmethoxysilane was not used, the change in solution viscosity with time was measured. The results were as follows. Initial 1,220 cps, 1 month after 60 ° C 4,500 cps

[0024]

According to the present invention, a silicone-based graft polymer having excellent storage stability can be easily obtained.
The silicone-based graft polymer is suitable as a paint base material or a coating agent.

Claims (1)

(57) [Claims] 1. A silicone compound obtained by subjecting the following compound (B) to a condensation reaction in a proportion of 0.8 to 3 mol per 1 mol of the following compound (A), an acidic or basic vinyl monomer and other A method for producing a silicone-based graft polymer having excellent storage stability, which comprises radically copolymerizing a vinyl monomer-containing monomer mixture in the presence of the following compound (C). Compound (A): Compound represented by Chemical Formula 1 (In the formula, n is a positive number of 10 to 600, and R ¹ and R ² are an alkyl group having 1 to 10 carbon atoms or a phenyl group.) Compound (B): a compound represented by Chemical formula 2 [Chemical 2] (In the formula, R ³ is a hydrogen atom or a methyl group, R is an alkyl group having 1 to 10 carbon atoms or a phenyl group, X is an alkoxy group having 1 to 10 carbon atoms or a halogen atom, and p Is 0 or 1) Compound (C): Compound represented by Chemical Formula 3 (R ⁴ , R ⁵ and R ⁶ are monovalent saturated hydrocarbon groups having 1 to 10 carbon atoms or a phenyl group, and R ⁷ is a methyl group or an ethyl group)