JP3194722B2 - Method for producing aqueous organopolysiloxane solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aqueous organopolysiloxane solution having excellent storage stability, and a method for producing the aqueous organopolysiloxane solution, which comprises the aqueous organopolysiloxane as a binder. The present invention relates to a coating composition that forms an excellent coating film.

[0002]

2. Description of the Related Art In recent years, volatile organic compounds (VOC),
Environmental regulations regarding reduction of toxicity and the like have become stricter, and from the viewpoint of resource saving, the paint industry has been switching from a paint using an organic solvent to a paint using water as a solvent. Aqueous paints using water as a solvent and in which the binder is a synthetic resin have been widely put into practical use, but inorganic paints using an organopolysiloxane as a binder tend to gel during storage and have storage stability. And its curability is poor, so that it has not been put to practical use.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is directed to a method for producing an aqueous organopolysiloxane solution having excellent storage stability, and the aqueous organopolysiloxane solution. It is an object of the present invention to provide a coating composition which forms a coating film having excellent curability, water resistance and stain resistance, using as a binder.

[0004]

That is, the present invention relates to the following inventions. 1. (I) (a) General formula (1), R ¹ _n Si (OR ² )
_{4-n wherein} R ¹ is an organic group having 1 to 8 carbon atoms;
² is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2
It is. 100 parts by weight of the organosilane and / or its partially hydrolyzed condensate, (b) 3 to 100 parts by weight of an amino group-containing alkoxysilane, and (c) a total of the components (a) and (b). A mixture consisting of 0.2 to 0.5 equivalent of water for 1 equivalent of the hydrolyzable functional group,
A step of conducting a hydrolysis-condensation reaction, and (II) an acid in an amount to neutralize 0.25 to 0.65 equivalents of amino groups in the hydrolysis-condensate of the partially hydrolyzed condensate solution obtained in step (I), and A step of adding at least 0.8 equivalent or more of water to 1 equivalent of the decomposable functional group, further subjecting the mixture to a hydrolysis condensation reaction, and then (III) adding a neutralizing agent and a neutralizing agent to the reaction solution obtained in step (II). Adding water for dilution according to the above method, wherein the method comprises the step of adding an aqueous organopolysiloxane solution having a pH of 5.5 or less. 2. A coating composition containing the aqueous organopolysiloxane obtained in the above item 1 as a binder.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Each component used for producing the aqueous organopolysiloxane solution of the present invention will be described. Component (a) component (a) has the formula _{^{(1), R 1 n Si}} (OR 2)
_{4-n wherein} R ¹ is an organic group having 1 to 8 carbon atoms;
² is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2
It is. And / or a partially hydrolyzed condensate thereof. In the above formula, examples of the organic group as R ¹ include an alkyl group, a cycloalkyl group, an aryl group, and a vinyl group.

Here, the alkyl group may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, and n
Preferable examples include an alkyl group such as -butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group and the like. Preferred alkyl groups have, for example, 1 to 4 carbon atoms.
Preferred examples of the cycloalkyl group include a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclononyl group. Further, as the aryl group, for example, a phenyl group, a naphthyl group and the like are preferably mentioned. Each of the above functions may optionally have a substituent. Examples of such a substituent include a halogen atom (for example, a chlorine atom, a bromine atom, a fluorine atom, and the like),
(Meth) acryloyl group, mercapto group, alicyclic group and the like are preferred.

The alkyl group as R ² may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group,
Alkyl groups such as a t-butyl group and a pentyl group are preferred. Preferred alkyl groups have, for example, 1 carbon atom.
~ 2. Specific examples of the organosilane represented by the above formula (1) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, and n-propyltriethoxysilane. , Isopropyltrimethoxysilane, isopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ
-Chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3,3,3-
Trifluoropropyltrimethoxysilane, 3,3,3
-Trifluoropropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, phenyltrimethoxysilane,
Phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, dimethoxymethylphenylsilane, dimethyldipropoxysilane, and the like, preferably, Methyltrimethoxysilane, methyltriethoxysilane, and dimethyldimethoxysilane.

These organosilanes can be used alone or in combination of two or more.
The component (a) may be a partially hydrolyzed condensate of the organosilane described above. The polystyrene-equivalent weight average molecular weight of the condensate is, for example, 300 to 5,000, preferably 500 to 3,000, and by using a condensate having such a molecular weight, storage stability is not impaired. A coating film having good adhesion can be obtained. Also,
Partially hydrolyzed condensate of the organosilane, and -OH group bonded to a silicon atom, the -OR ² group 1 or more, and preferably those having 3 to 30. Specific examples of such condensates include commercially available products such as SH6018 manufactured by Dow Corning Toray, SR2402, and DC303.
7, DC3074; KR-211 manufactured by Shin-Etsu Chemical Co., Ltd.
And KR-212, KR-213, KR-214, KR
-216, KR-218; TSR manufactured by Toshiba Silicone Co., Ltd.
-145, TSR-160, TSR-165, YR-
3187 and the like.

In the present invention, the component (a) comprises an organosilane having an n value of 1 in the above formula (1) and / or a partially hydrolyzed condensate (a-1) thereof, and an organosilane having an n value of 2 and / Or its weight ratio to the partial hydrolysis condensate (a-2) is (0: 100 to 70:30), preferably
The mixture of (5:95 to 60:40) is desirable because it is polymerized stably when producing the binder and a coating film having good crack resistance can be obtained. Component (b) The component (b) is an alkoxysilane having an amino group in the molecule and capable of undergoing a hydrolysis-condensation reaction. Preferably, an alkoxysilane represented by the following formula (2) is suitably used. it can. (R ⁵ —NH—R ⁴ —) _n Si (OR ³ ) _{4-n wherein} R ³ is an alkyl group having 1 to 5 carbon atoms;
⁴ is an alkylene group having 1 to 5 carbon atoms, R ⁵ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms, or It is a substituted or unsubstituted amino group, and n is the same as defined above. R ³ may be linear or branched. Examples of the alkyl group as R ³ include a methyl group, an ethyl group,
Preferable examples include alkyl groups such as propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group and pentyl group. Preferred alkyl groups have, for example, 1 to 2 carbon atoms.

The alkylene group as R ⁴ may be linear or branched. Examples of such an alkylene group include a methylene group, an ethylene group, and a propylene group. The range of the alkyl group having 1 to 5 carbon atoms as R ^{5 is the same} as in the case of R ³ . Also,
Examples of the cycloalkyl group as R ⁵ include a cyclohexyl group and a cycloheptyl group. Examples of the aryl group as R ⁵ include a phenyl group and a naphthyl group. Further, as the amino group as R ⁵ , a group in which one hydrogen atom or both hydrogen atoms of the amino group are substituted with, for example, the above-mentioned alkyl group having 1 to 5 carbon atoms is preferable. Examples of the amino group-containing alkoxysilane represented by such a formula include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β
-Aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl)-
γ-aminopropylmethyldiethoxysilane, N-cyclohexyl-γ-aminopropyltrimethoxysilane,
N-cyclohexyl-γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) -aminopropyltrimethoxysilane, γ- (2-aminoethyl) -aminopropylmethyldimethoxysilane, γ-anilinopropyltrimethoxysilane And the like.

The method for producing the aqueous organopolysiloxane solution of the present invention will be described. First, in the step (I),
The component (a) and the component (b) are subjected to hydrolysis and condensation in the presence of water. The mixing ratio of the component (a) and the component (b) is 100 parts by weight of the former and 3 to 1 in the latter.
00 parts by weight, preferably 5 to 50 parts by weight are suitable.
Incidentally, since the latter is less than the above range, the resulting organopolysiloxane does not stably dissolve or disperse in water, storage stability deteriorates, and conversely, if the amount is too large, the water resistance of the resulting coating film deteriorates. Not preferred. The amount of water is from 0.2 to 0.5 equivalent, preferably from 1 equivalent of the total hydrolyzable functional groups in the mixture of the components (a) and (b).
A suitable amount is 0.25-0.4 equivalent. If the amount of water is less than the above range, water dispersibility deteriorates, and if it is too large, polymerization stability such as gelation deteriorates, which is not preferable.

The hydrolysis-condensation reaction is usually carried out at 40 to 80
A method in which the reaction is carried out at a temperature of 45 ° C., preferably 45 to 65 ° C. for 2 to 5 hours is suitable, but the method is not limited to this method. In the step (I), a hydrolyzed condensate having a weight average molecular weight in terms of polystyrene of about 2500 to 20,000 is obtained. In addition, in this reaction system, it becomes a solution state by the alcohol generated by hydrolysis. In the step (I), since the reaction is carried out in the absence of an acid described later, unreacted organosilane tends to remain, which deteriorates the storage stability and curability. To carry out a hydrolytic condensation reaction in the presence of an acid and water. In addition, it is not preferable to carry out the reaction in the presence of an acid in the step (I) because the curability of the coating film deteriorates.

In the step (II), an amount for neutralizing 0.25 to 0.65 equivalents, preferably 0.35 to 0.60 equivalents of amino groups in the hydrolyzed condensate of the partially hydrolyzed condensate obtained in the step (I). And at least 0.8 equivalent or more, preferably 1.0 equivalent or more of water with respect to 1 equivalent of the total hydrolyzable functional groups, and the mixture is subjected to hydrolysis and condensation reaction. The acid has a reaction catalyst function and is blended in order to cause a reaction in a state of being stably dispersed or dissolved in a solution.
Examples of the acid include inorganic acids such as nitric acid and hydrochloric acid; and organic acids such as acetic acid, formic acid, and propionic acid. If the amount of the acid is less than the above range, unreacted organosilane is likely to remain unchanged, and storage stability and curability are deteriorated.On the contrary, if the amount is too large, polymerization stability such as gelation is deteriorated. It is not preferable. On the other hand, when the amount of water is smaller than the above range, the hydrolytic condensation reaction of unreacted organosilane becomes insufficient. The upper limit of the amount of water is such that the solid content of the finally obtained aqueous organopolysiloxane solution is 15 to 60% by weight, preferably 20 to 40% by weight.

The hydrolysis and condensation reaction is preferably carried out at 40 to 80 ° C., preferably at 45 to 65 ° C., for 2 to 5 hours, but is not limited to this method. (I
I) In the process, the weight average molecular weight in terms of polystyrene is about 500
0 to 50,000 hydrolyzed condensate is obtained, and the unreacted residue of the organosilane is eliminated. In the step (III), a neutralizing agent and, if necessary, water for dilution are added so that the reactant solution obtained in the step (II) can be used stably as a coating agent. As the neutralizing agent, the above-mentioned acids can be used, and the amount thereof is preferably such that the pH of the solution is 5.5 or less, preferably 2.5 to 4.5, because storage stability is good. The dilution water is
(II) When the amount of water added in the step is such that the solid content of the finally obtained solution is 15 to 60% by weight, preferably 20 to 4% by weight.
If the amount is less than 0% by weight, replenish the solid content.

In the aqueous organopolysiloxane solution thus obtained, an alcohol component is produced by the above-mentioned hydrolysis-condensation reaction, which remains in the solution. Therefore, the alcohol content may be removed under reduced pressure if necessary. Next, the coating composition of the present invention will be described. The coating composition of the present invention contains the above-mentioned aqueous organopolysiloxane as a binder, and if necessary, adjusts the solid content of the composition to preferably about 10 to 50% by weight. Water and organic solvents and fillers for improving the storage stability and coating workability of the composition, dyes, and further, various additives such as a curing agent, a curing accelerator, a thickener, and a pigment dispersant. It is composed of blended materials. Examples of the organic solvent include methanol, ethanol, propanol, alcohols such as butanol, ethylene glycol monoethyl ether,
Hydrophilic organic solvents such as alcohol ethers such as ethylene glycol monobutyl ether, ketones such as acetone and methyl ethyl ketone, and mixed organic solvents with various hydrophobic organic solvents for coatings such as toluene, xylene, ethyl acetate, and butyl acetate Can be used.

As the filler, there may be used extenders and coloring pigments for various coatings such as talc, barium carbonate, calcium carbonate, bentonite, titanium oxide, carbon black, red iron, lithopone, and the like. The curing agent and the curing accelerator are desirably compounded to accelerate the curability. Examples of the curing agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropylmethyl Epoxy compounds such as diethoxysilane are typical examples. These curing agents have an equivalent ratio of the epoxy groups thereof to the amino groups of the organopolysiloxane of (1: 0.3 to 1.5), preferably (1: 0.
A suitable amount is 5 to 1.0).

Examples of the curing accelerator include organotin compounds such as tin octylate, dibutyltin dilaurate, dibutyltin dimaleate and tributyltin laurate, ethylenediamine, diethylenetriamine, and the like.
Typical examples include amine compounds such as piperidine, phenylenediamine and triethylamine.
These curing accelerators are desirably added in order to cure the coating composition faster at a relatively low temperature, and the amount thereof is, for example, 0.1 to 100 parts by weight of the binder.
01 to 15 parts by weight are suitable. The coating composition of the present invention is applied to the surface of the object to be coated by means of a brush, spray, roll, dipping, or the like, at room temperature or at room temperature.
By baking at a temperature of 00 ° C. or less, a cured coating film can be formed.

In addition, as an object to be coated, an inorganic ceramics base material,
The present invention can be applied to various substrates such as stainless steel, aluminum and other metal substrates, glass substrates, plastic substrates, and paper substrates.

[0019]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, "parts" and "%" are shown on a weight basis unless otherwise specified. Example 1 In a reactor equipped with a reflux condenser and a stirrer, (a) a partially hydrolyzed cocondensate of phenyltrimethoxysilane and dimethyldimethoxysilane (D
C3074; solid content 100%), 30 parts, methyltriethoxysilane 4 parts, dimethyldiethoxysilane 16 parts, and (b) N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane 4 parts. After mixing, 2.6 parts of ion-exchanged water (total hydrolyzable functional groups 1
(Equivalent to 0.3 equivalent to the equivalent), and the mixture was subjected to a hydrocondensation reaction at 60 ° C. for 3 hours.

To 100 parts by weight of the obtained solution, 50 parts of ion-exchanged water and 3.5 parts of 5N-hydrochloric acid (corresponding to 0.6 equivalents of amino groups for neutralization) were added. For 3 hours. Next, after cooling, the ion-exchanged water 40
And 5N-hydrochloric acid were added so that the pH of the solution was 4.3, whereby an aqueous organosiloxane solution A having a solid content of 25.2% was prepared. Example 2 In a reactor equipped with a reflux condenser and a stirrer, (a) 30 parts of DC3074 manufactured by Dow Corning Toray Co., Ltd. and 20 parts of dimethyldiethoxysilane, and (b) N- (β-aminoethyl) After adding and mixing 4 parts of γ-aminopropyltrimethoxysilane, stirring, 2.6 parts of ion-exchanged water (corresponding to 0.3 equivalent to 1 equivalent of the total hydrolyzable functional group).
Was added and reacted at 60 ° C. for 3 hours.

To 100 parts of the obtained solution, 50 parts of ion-exchanged water and 3.5 parts of 5N hydrochloric acid (corresponding to an amount equivalent to 0.6 equivalents of amino groups) were added. Allowed to react for hours. Next, after cooling, 40 parts of ion-exchanged water and 5N-hydrochloric acid were added so that the pH became 4.3, and the solid content was 24.2.
% Aqueous organosiloxane solution B was prepared. Example 3 Reactor equipped with a reflux condenser and a stirrer, (a) 30 parts of DC3074 manufactured by Dow Corning Toray Co., Ltd., 6 parts of methyltriethoxysilane and 1 part of dimethyldiethoxysilane 1
3 parts and (b) 3 parts of N- (β-aminoethyl) γ-aminopropylmethyldiethoxysilane were added and mixed, and then, with stirring, 2.6 parts of ion-exchanged water (to 1 equivalent of the total hydrolyzable functional groups). (Equivalent to 0.31 equivalent) and pH 9.5
At 60 ° C. for 3 hours. The resulting solution 1
To 100 parts, 50 parts of ion-exchanged water and 1.8 parts of acetic acid (corresponding to the amount to neutralize 0.52 equivalents of amino groups) were added, and the mixture was reacted at 60 ° C. for 3 hours under the condition of pH 8.0. Next, after cooling, 90 parts of ion-exchanged water and acetic acid were added so that the pH of the solution became 4.0, thereby preparing an aqueous organosiloxane solution C having a solid content of 25%.

Comparative Example 1 A reactor equipped with a reflux condenser and a stirrer was charged with (a) (Toray
DC3074 manufactured by Dow Corning Co., Ltd .; solid content 100
%) 30 parts, methyltriethoxysilane 4 parts, dimethyldiethoxysilane 16 parts, and (b) N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane 4
After mixing, add 2.6 parts of ion-exchanged water while stirring.
(Equivalent to 0.3 equivalent to 1 equivalent of the total hydrolyzable functional groups) was added, and the mixture was hydrolyzed and condensed at 60 ° C. for 3 hours.
To 100 parts by weight of the obtained solution, 10 parts of ion-exchanged water was added and reacted at 60 ° C. for 3 hours. Then, after cooling,
80 parts of ion-exchanged water and 5N-hydrochloric acid were added to adjust the pH of the solution to 4.3, whereby an aqueous organosiloxane solution D having a solid content of 25.2% was prepared.

Comparative Example 2 In a reactor equipped with a reflux condenser and a stirrer, (a) (Toray
DC3074 manufactured by Dow Corning Co., Ltd .; solid content 100
%) 30 parts, methyltriethoxysilane 4 parts, dimethyldiethoxysilane 16 parts, and (b) N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane 1
After adding and mixing, ion-exchanged water 1
3 parts (corresponding to 1.5 equivalents relative to 1 equivalent of the total hydrolyzable functional groups) was added, and a hydrolysis condensation reaction was performed at 60 ° C. for 3 hours.

When 80 parts of ion-exchanged water was added to 100 parts by weight of the obtained solution and reacted at 60 ° C. for 3 hours, it gelled after 2 hours and was unsuitable as a coating composition. In order to examine the storage stability of each aqueous organosiloxane solution obtained in Examples 1 to 3 and Comparative Example 1, each solution was allowed to stand at 50 ° C. and compared with the initial state of the solution one month later. The viscosity change was measured, and the results are shown in Table 1. ：: Change in viscosity less than 1.2 times Δ: Change in viscosity 1.2 to less than 2.0 ×: Change in viscosity 2.0 times or more In addition, the aqueous organosiloxane solution 100 obtained in Examples 1 to 3 and Comparative Example 1 To 10 parts, 10 parts of γ-glycidoxypropyltrimethoxysilane (curing agent) and 5 parts of a 10% aqueous dispersion of dibutyltin dilaurate (curing accelerator) were added to prepare a coating composition.

For each coating composition, the appearance, hardness, hot water resistance, stain resistance, alkali resistance,
Various tests were conducted for solvent resistance, and the results are shown in Table 1. The test method was performed according to the following method. <Coating film performance test> A gypsum slag perlite plate (thickness: 12 mm) was used as a material, and a polyisocyanate prepolymer solution sealer "V-Selan # 100 Sealer" (trade name, manufactured by Dainippon Paint Co., Ltd.) : 100% dilution with a 1: 1 solution of xylene).
The composition was spray-coated so as to be １００100 g / m ² (wet weight). This was dried at 100 ° C. for 5 minutes.

Next, as a base paint, an acrylic silicone resin-based paint "V-Seran # 500 enamel" (trade name, manufactured by Dainippon Paint Co., Ltd.) (butyl acetate: xylene =
(A 40% dilution with a 1: 1 solution).
m ² (wet weight). This was dried at 120 ° C. for 15 minutes. Next, the coating amount of each of the above-mentioned coating compositions was (130 ± 10) g / m ² (w
(weight). 120 ° C
, And then dried at room temperature for 3 days. Appearance: visually determined. Hardness: Pencil hardness measured according to JIS K5400 Hot water resistance: The test piece was immersed in tap water at 60 ° C. for 7 days to visually determine the abnormality of the appearance of the coating film. ○ ・ ・ ・ No change △ ・ ・ ・ Slight change such as gloss reduction, whitening etc. × ・ ・ ・ Large change such as gloss reduction, whitening etc. Stain resistance: 24 hours after applying red or black magic ink The cloth was wiped with a cloth wetted with n-butanol, and the decontamination property was visually determined.・ ・ ・: Complete removal ・ ・ ・: Very slight contamination ・ ・ ・: Contamination ・ ・ ・: Extremely contaminated Alkali resistance: The state of the coating film after immersion in a saturated slaked lime aqueous solution for one week was visually determined. ◎ ・ ・ ・ No change ○ ・ ・ ・ Slightly lower gloss △ ・ ・ ・ Low gloss, slight whitening × ・ ・ ・ Low gloss, remarkable whitening Solvent resistance: cloth wetted with xylene and cloth wetted with n-butanol Rubbing test ○ ・ ・ ・ Both solvents passed 50 times rubbing test △ ・ ・ ・ Whitening of one solvent 50 times of rubbing test × ・ ・ ・ Both solvents whitened 50 times of rubbing test

[0027]

Table 1 Example Comparative Example 1 2 3 1 Aqueous organopolysiloxane solution ABCD Type Storage stability ○ ○ ○ × Appearance Good Good Good Slightly cloudy Hardness 2H 2H 2H H Hot water resistance ○ ○ ○ × Stain resistance ◎ ◎ ◎ ○ Alkali resistance ○ ○ ◎ △ Solvent resistance ○ ○ ○ △ As is clear from Table 1, all of Examples 1 to 3 in which the coating composition of the present invention was used as a top coat paint were stored. It had excellent stability and excellent coating properties.

On the other hand, Comparative Example 1, which is a coating composition obtained by performing a hydrolysis-condensation reaction in the absence of an acid, has poor storage stability, hot water resistance, and solvent resistance of the obtained coating film. Was. These poor film conditions are due to insufficient curability of the film.

[0029]

The aqueous organopolysiloxane solution produced by the method of the present invention has excellent storage stability, and the coating composition using the aqueous organopolysiloxane as a binder has excellent curability, water resistance and stain resistance. To form an excellent coating film.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 77/388 C08G 77/06 C08G 77/26 C08L 83/04

Claims (1)

(57) [Claims] 1. A (I) (a) the general formula _{^{(1), R 1 n Si}} (O
R ² ) _{4-n wherein} R ¹ is an organic group having 1 to 8 carbon atoms, R ² is an alkyl group having 1 to 5 carbon atoms, and n is 1
Or 2. 100 parts by weight of the organosilane and / or its partially hydrolyzed condensate, (b) 3 to 100 parts by weight of an amino group-containing alkoxysilane, and (c) a total of the components (a) and (b). Hydrolyzing and condensing a mixture consisting of 0.2 to 0.5 equivalents of water with respect to 1 equivalent of the hydrolyzable functional group, and then (II) hydrolyzing and condensing the partially hydrolyzed condensate solution obtained in step (I). Adding an acid in an amount to neutralize 0.25 to 0.65 equivalents of amino groups in the product, and at least 0.8 equivalents or more of water relative to 1 equivalent of the total hydrolyzable functional groups, and further subjecting to hydrolysis and condensation, (III) A method for producing an aqueous organopolysiloxane solution having a pH of 5.5 or less, comprising: adding a neutralizing agent to the reaction product solution obtained in the step (II).