JPH0149171B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a silicone resin, and particularly to a method for producing a silicone resin that is soluble in organic solvents and has excellent heat resistance. Conventionally, the method for producing silicone resins soluble in organic solvents is to form two layers with a ketone (A) that cannot be mixed with water in any proportion and water containing an amine (B), and then add an alkyl trifluoride to this layer. A method of adding chlorosilane to perform hydrolysis and condensation reactions of alkyltrichlorosilane at the interface between two layers (Japanese Patent Application Laid-open No.
50-111198) is known. However, the silicone resin obtained by this reaction has a too low molecular weight, so it is difficult to collect the precipitate, and although it is certainly soluble in organic solvents immediately after the reaction, it becomes insoluble in organic solvents when left at room temperature. It has the disadvantage of poor storage stability and is extremely difficult to handle. On the other hand, as a method for producing high molecular weight silicone resin, methyltrialkoxysilane with a chlorine content of 0.1 to 5.0% by weight is hydrolyzed and condensed in a solution containing an alkaline earth metal hydroxide or an alkali metal carbonate. Method of conducting the reaction (Special Publication 1984-
39808), a method in which organohalogensilane and bifunctional siloxane are co-hydrolyzed to form an inert solvent solution, and then a strong alkaline substance such as a metal hydroxide is added to react at room temperature to 160°C (specially Publication No. 50-34600) is known. However, in conventional methods carried out in the presence of these metal hydroxides, it is difficult to control the reaction and lacks reproducibility.Furthermore, it is inevitable that the catalyst will be mixed into the silicone resin produced, and as a result, contamination during high-temperature heating. Catalytic polymerization occurs due to the catalyst, and it has disadvantages such as the inability to obtain products with excellent thermal stability. An object of the present invention is to eliminate the drawbacks of the above conventional methods and to produce a high molecular weight silicone resin from alkoxysilanes that is soluble in organic solvents and has excellent storage stability and thermal stability. The method for producing silicone resin of the present invention is based on the general formula
Trialkoxysilanes alone represented by R ₁ Si(OR ₂ ) ₃ (in the formula, R ₁ is a hydrogen atom, a lower alkyl group, an alkenyl group, or an aryl group, and R ₂ is a lower alkyl group), or the trialkoxysilane Silanes and the general formula R ₃ R ₄ Si(OR ₅ ) ₂ (where R ₃ and
R ₄ is the same or different and is represented by a hydrogen atom, a lower alkyl group, an alkenyl group, or an aryl group, and R ₅ is a lower alkyl group) in the presence of an organic solvent, water, and an organic base. It is characterized by a heating reaction. When carrying out the method of the present invention, the general formula
Trialkoxysilanes represented by R ₁ Si(OR ₂ ) ₃ alone, or the trialkoxysilanes and dialkoxysilanes represented by the general formula R ₃ R ₄ Si(OR ₅ ) ₂ are mixed in an organic solvent and water. and heating in the presence of an organic base to cause hydrolysis and condensation reactions. General formula R ₁ Si used in the method of the present invention
( _OR2 ) _R1 in the trialkoxysilanes represented by ₃ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Preferred are hydrogen atom, methyl group, ethyl group, vinyl group, allyl group, propenyl group, phenyl group, and tolyl group. Further, R ₂ is preferably an alkyl group having 1 to 5 carbon atoms, particularly a methyl group or an ethyl group. Examples of these trialkoxysilanes include trimethoxysilane, triethoxysilane,
Methyltrimethoxysilane, methyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, propyltripropoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyltributoxysilane, pentyltriethoxysilane, Vinyltrimethoxysilane, vinyltriethoxysilane, allyltripropoxysilane,
Allyltributoxysilane, propenyltriethoxysilane, propenyltripropoxysilane,
Putenyltrimethoxysilane, butenyltriethoxysilane, pentenyltributoxysilane, pentenyltripentoxysilane, phenyltrimethoxysilane, phenyltripropoxysilane,
Tolyltrimethoxysilane, tolyltributoxysilane, dimethylphenyltrimethoxysilane,
Examples include ethyl phenyltrimethoxysilane, ethyl phenyltriethoxysilane, butylphenyltripropoxysilane, and butylphenyltrimethoxysilane. In addition, R ₃ or R ₄ in dialkoxysilanes represented by the general formula R ₃ R ₄ Si(OR ₅ ) ₂ is as follows:
A hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an aryl group having 6 to 10 carbon atoms are preferred, particularly a hydrogen atom, a methyl group, an ethyl group, a vinyl group, and an allyl group. , propenyl group, phenyl group or tolyl group are preferred. Furthermore, R ₅ is preferably an alkyl group having 1 to 5 carbon atoms, particularly a methyl group or an ethyl group. Examples of these dialkoxysilanes include methyldimethoxysilane, methyldiethoxysilane, methyldibutoxysilane, ethyldipropoxysilane, ethyldipentoxysilane, propyldimethoxysilane, propyldiptoxysilane, butyldiethoxysilane, and pentyldimethoxysilane. Dibutoxysilane, vinyldimethoxysilane, phenyldiethoxysilane, tolyldimethoxysilane, dimethyldimethoxysilane, diethyldipropoxysilane, ethylpropyldiethoxysilane, dipropyldimethoxysilane, methylpentyldigtoxysilane, methylvinyldiethoxysilane, Ethylallyldimethoxysilane, propylbutenyldipropoxysilane,
Ethyl phenyl dimethoxysilane, butyl phenyl diethoxy silane, methyl tolyl dipropoxy silane, ethyl (dimethyl phenyl) dibutoxy silane, phenyl vinyl dimethoxy silane, tolylyl diethoxy silane, phenyl butenyl dipropoxy silane, etc. I can give it to you. These trialkoxysilanes or dialkoxysilanes may be used alone or in combination of two or more. Further, trialkoxysilanes can be used alone or in combination with the above-mentioned dialkoxysilanes. When trialkoxysilanes and dialkoxysilanes are used together, the amount of dialkoxysilanes is less than 1 mol, particularly preferably 0.5 mol or less, per mol of trialkoxysilanes. The higher the ratio of dialkoxysilanes to trialkoxysilanes, the lower the softening temperature of the obtained silicone resin, and the lower the temperature at which weight loss by heating begins. When both are used together, a mixture of trialkoxysilanes and dialkoxysilanes may be simultaneously hydrolyzed and condensed,
After hydrolyzing and condensing one of trialkoxysilanes or dialkoxysilanes, the other may be added and further hydrolyzed and condensed, and the method and order of these additions are not particularly limited. . The organic solvent used in the present invention is not particularly limited as long as it dissolves the alkoxysilanes mentioned above and is inert to hydrolysis and condensation reactions.
Among these solvents, particularly preferred are ketones, esters, ethers, alcohols, etc. Examples of ketones include methyl ethyl ketone,
Esters such as methyl isobutyl ketone and dietherketone include n-butyl acetate and isoamyl acetate; ethers include tetrahydrofuran, ethylene glycol, dimethyl ether, and dioxane; alcohols include hexanol,
Examples include 4-mether-2-pentanol. These organic solvents can be used alone or in combination with others. The appropriate amount of the organic solvent to be used is 3 to 30 parts by volume per 1 part by volume of the total amount of trialkoxysilanes and dialkoxysilanes. Preferred organic bases are usually primary to tertiary amines, such as aliphatic amines or aromatic amines such as triethylamine, tripropylamine, tributylamine, diethylamine, ethylamine, dipropylamine, ethylenediamine, triethylenediamine, aniline, and pyridine. used. Particularly preferred organic amines are organic amines having an acid dissociation constant (pKa) in water of 7 or more, particularly preferably those having a pKa of 10 or more, such as triethylamine and diethylamine. The amount of organic amines used varies depending on the type of amine used and the reaction conditions, and is not particularly limited, but is generally about 0.05 to 3 times the mole relative to the total amount of trialkoxysilanes and dialkoxysilanes. The appropriate amount of water to be used is about 3 to 30 times the molar amount of the total amount of trialkoxysilanes and dialkoxysilanes. The same applies to the amount used in the case of organic bases other than amines. In the method of the present invention, the hydrolysis and condensation reactions are carried out by mixing an organic solvent in which an alkoxysilane is dissolved, water and an organic base, and heating this mixture in an oil bath or the like. The heating temperature is usually 130°C or lower, but it is preferably heated at 60 to 120°C for about 1 to 6 hours. Note that during the heating operation, the mixed liquid may be stirred, or the mixed liquid may be left under reflux. After the reaction is completed, separate the organic solvent layer from the reaction solution,
Wash with water. Washing with water containing a small amount of salt, such as an aqueous ammonium nitrate solution of about 0.2% by weight, facilitates the washing operation. After washing until the water becomes neutral, if necessary, dry the organic solvent layer with a drying agent such as anhydrous calcium sulfate or molecular sieves, and concentrate to dryness to obtain the desired silicone resin. can get. Incidentally, instead of the above concentration and dryness, the silicone resin may be separated by pouring the liquid concentrated to an appropriate concentration into a solvent that does not dissolve the silicone resin, such as acetonitrile. The silicone resin obtained in this way usually has a polystyrene equivalent number average molecular weight of 3000 to 3000.
200,000, it has good storage stability and will not become insolubilized even if stored at room temperature for a long time, for example, 2 to 3 months. The silicone resin obtained by the method of the present invention is
When trialkoxysilanes alone are used as raw materials,
Infrared absorption spectrum around 1135cm ^-1 and 1040cm ^-1
Strong absorption is observed nearby. On the other hand, the following general formula () (In the formula, R ₆ is an organic group, and n means the number of repeats.) Organopolysilsesquioxane soluble in organic solvents has Si-O-Si bonds near 1135 cm ^-1 and 1040 cm ^-1 . Because it shows two strong and specific absorptions based on stretching motion (J. Polym. Sci., C
The silicone resin of the present invention also has the general formula ()
It is thought that it has the following structure. On the other hand, when a mixture of trialkoxysilanes and dialkoxysilanes is used as a raw material, silsesquioxane units (R ₁ SiO _1.5 ) and diorganosiloxane units (R ₃ R ₄ SiO) are included. It is thought that the silicone resin has a mixed structure. In addition, even when one of trialkoxysilanes or dialkoxysilanes is subjected to hydrolysis and condensation reaction, the other one is further added, and the hydrolysis and condensation reaction is performed again, the silsesquioxane unit (R ₁ SiO _1.5 ) and diorganosiloxane units (R ₃ R ₄ SiO) are considered to be a mixture of silicone resins. The silicone resin obtained by the method of the present invention is
It is soluble in organic solvents, does not become insolubilized in organic solvents even if left in a solid state at room temperature for a long period of time, and has good storage stability. Furthermore, this silicone resin has excellent heat resistance and excellent adhesion to substrates, so it can be used in a wide range of applications, for example, as a heat-resistant insulating film.
Specific applications include, for example, insulating protective films or interlayer insulating films for integrated circuits, liquid crystal alignment auxiliary films, heat-resistant paints, and modifiers for organic polymer surfaces. In addition, the method of the present invention does not use halogen compounds or metal hydroxides in the process, so the produced silicone resin is not contaminated with halogens or metals, and is especially suitable for integrated circuits that require high purity. It is suitable as a material in the electrical and electronic fields, such as an insulating protective film or an interlayer insulating film, a sealing or insulating material for semiconductor elements, and a material for magnetic memory. Examples of the method of the present invention are shown below, and the average molecular weight in the examples is a standard polystyrene equivalent number average molecular weight determined by gel permeation chromatography (hereinafter referred to as GPC) described below. GPC measurement method Equipment: High-temperature, high-speed gel permeation chromatogram (Model 150-
CALC/GPC) Column: Showa Denko K.K. SHODEX A-8M, length
50 cm Measurement temperature: 40°C Flow rate: 1 c.c./min Sample: 1 g of silicone resin was dissolved in 100 ml of tetrahydrofuran. As the standard polystyrene, standard polystyrene manufactured by Plessyer Chemical Company, USA was used. Example 1 In a reaction vessel equipped with a reflux condenser, a stirring bar, and a dropping funnel, 495 ml (3.95 mol) of methyl isobutyl ketone, 49.5 ml (0.35 mol) of methyltrimethoxysilane, and 12 ml (0.086 mol) of triethylamine were added.
added. Add water to this solution while stirring from the dropping funnel.
Although 66 ml (3.67 mol) was added dropwise, almost no heat generation was observed. Next, the reaction solution was heated at an oil bath temperature of 80°C for 4 hours to cause condensation, and after the reaction was completed, the organic solvent layer was separated and treated with a 0.2% by weight ammonium nitrate aqueous solution.
Washing was performed until the washing aqueous solution became neutral. Furthermore, after drying the organic solvent layer with molecular sieves, low boiling point substances were distilled off under reduced pressure to obtain a solid content. When this solid content is vacuum dried at 40℃ overnight,
14.3 g of silicone resin was obtained. The average molecular weight of this resin was 25,000. Example 2 198 ml (1.5 mol) of n-butyl acetate, 49.5 ml (0.35 mol) of methyltrimethoxysilane, 12 ml (0.086 mol) of triethylamine and 66 ml of water
(3.67 mol) and other operations and post-treatments were performed in the same manner as in Example 1 to obtain 14.1 g of silicone resin. The average molecular weight of this product was 30,000. Example 3 Same as Example 1 using 198 ml (1.56 mol) of 4-methyl-2-pentanol, 49.5 ml (0.35 mol) of methyltrimethoxysilane, 12 ml (0.086 mol) of triethylamine and 66 ml (3.67 mol) of water. After proper operation and post-treatment, 13.8g of silicone resin
I got it. The average molecular weight of this product was 18,000. Example 4 247.5 ml (3.06 mol) of tetrahydrofuran, 49.5 ml (0.35 mol) of methyltrimethoxysilane, 12 ml (0.086 mol) of triethylamine and 66 ml of water
(3.67 mol) was used, and other operations and post-treatments were carried out in the same manner as in Example 1, to obtain 14.8 g of silicone resin. The average molecular weight of this product was 23,000. Example 5 A solution of 432 ml (3.45 mol) of methyl isobutyl ketone, 36 ml (0.25 mol) of methyltrimethoxysilane and 3.3 ml (0.032 mol) of diethylamine is added with 48 ml of water.
ml (2.67 mol) and then heated at 80°C for 3 hours. Then, when post-treated in the same manner as in Example 1,
10.1 g of silicone resin was obtained and the average molecular weight was 35,000. Example 6 42 ml (0.3 mol) of methyltrimethoxysilane, 6.9 ml (0.05 mol) of dimethyldimethoxysilane and 12 ml (0.086 mol) of triethylamine were dissolved in 450 ml (3.59 mol) of methyl isobutyl ketone,
After adding 66 ml (3.67 mol) of water to this solution,
Heat condensation was carried out at 90°C for 5 hours. Then, the organic solvent layer was separated and diluted with 0.2% by weight ammonium nitrate aqueous solution.
Washing was performed until the washing water became neutral. After further concentrating the organic solution, the concentrated liquid was poured into acetonitrile, and the silicone resin was solidified and separated. This was vacuum dried overnight to obtain 13.1 g of silicone resin. The average molecular weight of this product was 20,000. Example 7 42 ml (0.3 mol) of methyltrimethoxysilane and 10 ml (0.072 mol) of triethylamine were dissolved in 380 ml (3.04 mol) of methyl isobutyl ketone,
After adding 54 ml (3.17 mol) of water to this solution,
Heated at 80°C for 2 hours. After cooling the reaction solution, add 6.9 ml (0.05 ml) of dimethylmethoxysilane to it.
mol) was added and further heated at 80°C for 2 hours.
Subsequently, the product was post-treated in the same manner as in Example 6 to obtain 13 g of silicone resin. The average molecular weight of this substance is
It was 24,000. Example 8 11.5 ml (0.088 mol) of triethylamine, 40 ml (0.279 mol) of methyltrimethoxysilane, 5.3 ml (0.035 mol) of vinyltrimethoxysilane, 6.5 ml (0.035 mol) of phenyltrimethoxysilane, 363 ml (2.9 mol) of methylisobutylketone ) and water 67.5
ml (3.75 mol) and other operations and post-treatments were performed in the same manner as in Example 1 to obtain 17 g of silicone resin. The average molecular weight of this product was 22,000. Example 9 10.3 ml (0.079 mol) of triethylamine, 40 ml (0.279 mol) of methyltrimethoxysilane and 4.8 ml (0.031 mol) of vinyltrimethoxysilane are dissolved in 356 ml (2.84 mol) of methyl isobutyl ketone, and 60 ml (2.84 mol) of water is added to this solution. After adding 3.33 mol), the mixture was heated at 80°C for 2 hours. Then, post-treatment was carried out in the same manner as in Example 1 to obtain 15 g of silicone resin. The average molecular weight of this product was 24,000. Example 10 16 ml (0.112 mol) of methyltrimethoxysilane,
Phenyltrimethoxysilane 2.3ml (0.012mol),
Using 4.1 ml (0.031 mol) of triethylamine and 128 ml (1.02 mol) of methyl isobutyl ketone,
Other operations and post-treatments were performed in the same manner as in Example 1.
6 g of silicone resin was obtained. The average molecular weight of this product was 30,000. Example 11 490 ml (3.90 mol) of methyl isobutyl ketone, 13.7 ml (0.098 mol) of triethylamine and 36 ml of water
A mixed solution of 22.6 ml (0.18 mol) of methyl isobutyl ketone, 24.6 ml (0.17 mol) of methyltrimethoxysilane, and 2.8 ml (0.02 mol) of trimethoxysilane was added dropwise to the mixed solution (2.0 mol) over about 10 minutes. Thereafter, the reaction solution was heated and condensed at 70°C for 3 hours. Subsequently, 11.0 g of silicone resin was obtained by post-treatment in the same manner as in Example 1. The average molecular weight of this resin was 17,000. Example 12 495 ml (3.95 mol) of methyl isobutyl ketone, 67.0 ml (0.35 mol) of butyltrimethoxysilane, 12 ml (0.086 mol) of triethylamine, 66 ml (3.67 mol) of water.
13.0 g of silicone resin was obtained by carrying out the same operation as in Example 1 except using mol). The average molecular weight of this product was 23,000. Example 13 495 ml (3.95 mol) methyl isobutyl ketone, 55 ml (0.35 mol) ethyltrimethoxysilane, 12 ml (0.086 mol) triethylamine and 66 ml water
(3.67 mol) and the same operation as in Example 1 was performed except for the same procedure as in Example 1 to obtain 13.0 g of silicone resin. The average molecular weight of this resin was 21,000. Experimental Example 1 The thermal decomposition temperatures of the silicone resins obtained in Examples 1 to 13 under nitrogen were as shown in Table 1.

【table】

[Table] From the results in the above table, it can be seen that the silicone resin obtained according to the present invention, especially the resin obtained by thermosetting the silicone resin using trialkoxysilane alone as a raw material, exhibits extremely high heat resistance. As described above, according to the present invention, a thermosetting resin that does not become insolubilized in an organic solvent even when stored at room temperature for a long period of time can be obtained, and by thermoforming this resin, a silicone resin product with excellent heat resistance can be produced. Obtainable. Furthermore, since the method of the present invention does not use metal hydroxides at all, the obtained silicone resin has excellent thermal stability during high-temperature heating, and since the metal content is extremely low, it also has excellent electrical properties such as insulation resistance. There is.

Claims (1)

[Claims] 1 General formula R ₁ Si(OR ₂ ) ₃ (wherein R ₁ is a hydrogen atom, a lower alkyl group, an alkenyl group, or an aryl group,
R ₂ means a lower alkyl group) alone or together with the trialkoxysilanes represented by the general formula R ₃ R ₄ Si(OR ₅ ) ₂ (in the formula
R ₃ and R ₄ are the same or different, and are a hydrogen atom, a lower alkyl group, an alkenyl group, or an aryl group,
A method for producing a silicone resin, which comprises subjecting a dialkoxysilane represented by (R ₅ means a lower alkyl group) to a heating reaction in the presence of an organic solvent, water and an organic base.