JPH02272041A - Colloidal silica-containing resin composition and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject composition, homogeneously containing colloidal silica and excellent in surface hardness, abrasion resistance, processability, etc., by mixing an alcohol dispersion of the colloidal silica with a resin solution consisting of an organic solution and then removing the alcohol. CONSTITUTION:The objective composition obtained by blending and mixing (A) a liquid prepared by dispersing colloidal silica having 0.005-0.1mum particle diameter in an alcohol (e.g. sec-butyl alcohol) with (B) a solution obtained by dissolving a resin (e.g. an acrylic resin) in an organic liquid (e.g. ethyl acetate) at (99/1)-(5/95) weight ratio of the resin to the colloidal silica, heating the resultant blend and removing the alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a colloidal silica dispersion resin liquid in which the dispersion is stabilized with a resin in an organic liquid. This method is characterized in that colloidal silica particles are protected by a resin and can therefore maintain a stable dispersion state even in dihydrophobic or hydrophilic organic solvents.

[Prior Art and its Problems] Colloidal silica is particles of silicic anhydride and is generally commercially available in a state dispersed in water or an alcoholic solvent. Colloidal silica itself does not have the ability to form a film, and becomes powdered by evaporation of water or alcoholic solvent. For this reason, it is often used in combination with a resin liquid capable of forming a film. However, since colloidal silica has an active and hydrophilic surface, it aggregates when mixed with a hydrophobic organic solvent or resin liquid. A film obtained from a resin liquid containing colloidal silica in such an aggregated state loses its luster and becomes weak in mechanical strength. Therefore, colloidal silica can only be used in a stable dispersion state when mixed with a resin soluble in water or alcoholic solvents. However, the resin liquid obtained in this way has poor storage stability and has problems such as thickening and precipitation.

[Means for Solving the Problems] The present inventors have intensively studied a manufacturing method for maintaining a stable dispersion state of colloidal silica in an organic solvent in the presence of a resin soluble therein. We were able to accomplish the present invention. That is, the present invention is characterized in that a resin solution dissolved in an organic liquid is mixed with an alcohol dispersion of colloidal silica, and then the alcohol is distilled off to stabilize the dispersion of colloidal silica with the resin solution. The present invention relates to a method for producing a colloidal silica-containing resin composition, and a colloidal silica-containing resin composition characterized in that colloidal silica is dispersed in a resin solution dissolved in an organic liquid.

In the colloidal silica dispersion obtained by the present invention, the resin forms a dispersion stable layer on the surface of the colloidal silica particles through chemical bonding and/or physical adsorption, and therefore,
A stable dispersion state can be maintained even in aqueous organic solvents.

The material obtained from this dispersion contains uniformly distributed colloidal silica, so it has excellent properties.
A product that satisfies surface hardness, wear resistance, scratch resistance, impact resistance, workability, and surface smoothness at the same time can be obtained. Furthermore, because it has excellent chemical and thermal durability, it can be used in various fields such as paints, adhesives, and molding materials.

Furthermore, since the production method according to the present invention can be applied to various resins, it is possible to further improve the properties of each resin.

The present invention will be explained in more detail below.

The resin forming the stable dispersion layer of colloidal silica can be used without any restriction as long as it is soluble in an organic solvent. These resins have a number average molecular weight of 500
~1ooo, ooo are used, but oligomers (number average molecular weight of 10,000 or less) can also be used.

The blending ratio of the above resin and colloidal silica is 599/1 ~
It is carried out at a weight ratio of 5/95.

Representative examples of these resins are shown below.

In addition to synthetic resins such as acrylic resin, polyamide, polyester, alkyd resin, polystyrene, polyvinyl chloride, polyether, polyurethane, urea resin, polyisoprene, phenolic resin, epoxy resin, and melamine resin,
Natural polymers such as cellulose and rubber can also be used.

These materials may contain one or more components such as block copolymers and graft copolymers obtained by known methods. Alternatively, those that have been chemically modified may also be used.

These resins can provide a stable dispersion when chemically bonded to the silica surface. For this purpose, it is preferable that the resin contains a hydroxyl group, or a functional group such as an alkoxysilane group or a carboxyl group that can react with a silanol group on the surface of the colloidal silica. These functional groups can be introduced into each resin by conventionally known reactions.

The dispersion liquid of the present invention is obtained by replacing alcohol with an organic liquid other than alcohol. As such organic liquids, ester/ether solvents, ketone solvents, aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, etc. are used. Examples of ester/ether solvents include ethyl acetate, isopropyl acetate, amyl acetate, 5ec-amyl acetate, isobutyl acetate, butyl acetate, methyl amyl acetate, methyl cellosolve acetate, butyl carbitol acetate, 3-methoxybutyl acetate, methyl Examples include carbitol acetate, cellosolve acetate, 2-ethylhexyl acetate, carbitol acetate, and the like.

Examples of ketone solvents include acetone, methyl ethyl ketone, methyl propyl ketone, cyclohexanone,
Examples include methylcyclohexanone, methylisobutylketone, methylpropylketone, methylisoamylketone, methylamylketone, mesityl oxide, ethylbutylketone, diisobutylketone, methylhexylketone, pentoxone, ethylamylketone, isophorone, and the like.

Examples of the aromatic hydrocarbon solvent include benzene, xylene, toluene, aromatic petroleum naphtha, orthodichlorobenzene, dipentene, and tetrahydronaphthalene.

Examples of the aliphatic hydrocarbon solvent include n-hexane, heptano, octane, petroleum naphtha, and the like.

Examples of other solvents include methylene chloride, trichloroethylene, carbon tetrachloride, 2-nitropropane, and dimethylformamide.

These may be used alone or in combination of two or more, but for -Jl19, one with particularly strong polarity is selected from among ether, ester, and ketone types, and this is used as the main component. It is preferable to combine this with aromatic and aliphatic compounds as appropriate.

The colloidal silica used in the present invention has a particle size of 0.00
Those having a diameter of 5 μm to 0.1 μm are effective, and a solution prepared by dispersing silicic anhydride in an alcoholic solvent or the like is used, and those produced by a well-known method and commercially available can be used.

As the alcohol, an alcohol having 1 to 10 carbons is used, preferably colloidal silica dispersed in an alcohol having 1 to 5 carbons. Examples of the alcohol used include 5ec-butyl alcohol, isopropyl alcohol, ethyl alcohol, methyl alcohol, tert-butyl alcohol, n
-Amyl alcohol, isobutyl alcohol, isopropyl cellosolve, tetrafurfuryl alcohol, n-butyl alcohol, methylisobutyl carbinol and the like.

The dispersion liquid of the present invention is obtained by mixing the resin described above, an organic liquid, and colloidal silica dispersed in alcohol, and distilling off the alcohol under heating. At this time,
The organic liquid may be added while being added.

In order to efficiently react the silanol groups on the surface of the colloidal silica with the hydroxyl groups, alkoxysilane groups, or carboxyl groups in the resin, an acid catalyst or a base catalyst can be used. Examples of acid catalysts include carboxylic acids (
Examples of base catalysts include monoethanolamine, jetanolamine, tributylamine, triethylamine, ammonia, hydroxide Examples include sodium.

(Thus, a dispersion of colloidal silica stabilized by a resin in an organic liquid is obtained. This dispersion can be used as it is or by adding other resins, curing agents, colorants, etc. can.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In Examples and Comparative Examples, parts and % are both parts by weight and % by weight.

In a flask equipped with a thermometer, stirrer and water separator, add 473.4 parts of phthalic anhydride, 133.4 parts of adipic acid, 239.9 parts of neopentyl glycol, and 239.9 parts of ethylene glycol.
5B, 7//trimethylolpropane
187.1//monobutyltin hydroxide
1.0〃 was charged, and the contents were heated to 230°C for 4 hours while stirring. After further heating at 230°C for 2 hours, 5% xylene was added to the total amount of 23
The temperature was maintained at 0° C. and heating was continued until the acid value reached 5. When the acid value reached 5, heating was stopped, and the mixture was diluted with cyclohexanone so that the heating residue was 50%. The resulting oil-free polyester resin liquid had a viscosity of E and a weight average molecular weight of 15,000.

Colloidal silica 1 of A In a flask equipped with a thermometer, stirrer, dropping funnel, and solvent separator, () is 160 (80) parts of resin liquid A for dispersing solids Colloidal silica isopropanol solution 67 (20) / / (manufactured by Catalysts & Chemicals Co., Ltd. (OS CA L-1436) Cyclohexanone 173 Hydrochloric acid
0.2 〃 was added and heated. While dropping cyclohexanone from the dropping funnel at reflux temperature, a fraction equivalent to the dropped cyclohexanone was removed from the solvent separator. When the temperature of the fraction became equal to the boiling point of cyclohexanone, the dropwise addition was stopped and cyclohexanone was distilled off until the nonvolatile content was 50%. The viscosity of the obtained dispersion was C. Also, 50℃. No change in the viscosity of the dispersion was observed even after storage for 6 months.

It was heated to 100°C. The following monomers and polymerization initiators were added dropwise thereto over 3 hours, and after the addition, the mixture was aged for 2 hours.

Styrene 95 parts Methyl methacrylate 55 2-hydroxyethyl methacrylate 50 2.2'-azobisisobutyronitrile 2 The obtained acrylic resin face has a nonvolatile content of 50%, a viscosity F and a weight average molecular fi of 20000.
Met.

Colloidal Silica 2 A dispersion 2 of colloidal silica dispersed in acrylic resin B was obtained using the same composition and method, except that the oil-free polyester resin liquid A of Production Example 1 was changed to the above-mentioned acrylic resin liquid B. The non-volatile content was 50% and the viscosity was C. Furthermore, there was no change in the viscosity of the dispersion even after storage at 50°C for 6 months.

Add 200 parts of cyclohexanone to a flask equipped with a thermometer, condenser, and stirrer, and add the oil-free polyester resin liquid A of Production Example 1 with the same non-volatile content of 50%.
Except for changing to epoxy resin liquid C, which is made by dissolving Epon 1001 (manufactured by Yuka Shell Co., Ltd.) in cyclohexanone.
A dispersion liquid 3 of colloidal silica dispersed in an epoxy resin was obtained using the same composition method 5. The non-volatile content was 50% and the viscosity was H. Further, there was no change in the viscosity of the dispersion even after storage at 50°C for 6 months.

1. Blend 16 parts of Kneepan 20SE-60 (manufactured by Mitsui Toatsu Chemical Co., Ltd.) as a hardening agent to 100 parts of the solid content of colloidal silica dispersion resin liquids 1 to 3. The weight ratio of the hardening agent was 80/20), which was applied to each test plate (thickness 3.5 mm, zinc phosphate treatment) and baked at 140°C for 30 minutes to harden it (cured film thickness 20-25 μm). . Table 1 shows the appearance of the obtained coating film and the results of each test.

Enaktanyu Polyester Resin Liquid A and Hardening Agent (Kneepan 20SE-
60 (manufactured by Mitsui Toatsu Chemical Co., Ltd.) was blended at a solid content ratio of 80/20, and the mixture was applied to each test plate and baked at 140° C. for 30 minutes to cure it (cured film thickness: 20 to 25 μm). Table 1 shows the appearance of the obtained coating film and the results of each test.

Engineering Comparison ■Upolyester resin liquid A, colloidal silica isopropanol dispersion (manufactured by Catalysts Kasei Kogyo Co., Ltd.), and curing agent (Niepan 20SE-60) were blended at the following solid proportions and painted on each test plate. After baking at 140° C. for 30 minutes, the appearance of the resulting coating film and the test results are shown in Table 1.

Polyester resin A 80 parts Improper tool dispersion of colloidal silica 20 (manufactured by Catalysts & Chemicals Co., Ltd.) Curing agent 16
The blend had thickened significantly after storage for 6 months at 50°C.

(Note) l) Flexibility: Tested under the conditions of JIS K5400. The cracking and peeling of the coating film was observed when the diameter of the mandrel was 2 mm and the thickness of the auxiliary plate was 4 mm+.

○: There was no damage to the coating film such as cracking or peeling. ×: There was cracking or peeling. 2) Substrate: The test was conducted under the conditions of JIS K5400.

Peel off the squares with cellophane tape, total number of 100.
Evaluation was made based on the number of squares that remained without being peeled off.

3) Abrasion resistance: The degree of scratches caused when the coating surface was rubbed with a sponge coated with cleanser was evaluated as follows.

○: No scratches even with strong friction Δ: 〃 Then, scratches occur (×: Scratches occur even with light friction 4) Smoothness: Place a weight of I kg on the painted surface and move it at a constant speed. The smoothness was evaluated by the force (Kg) required to pull the weight horizontally.

5) Chemical resistance: 1. ON hydrochloric acid, 1. A drop of ON sodium hydroxide aqueous solution or cyclohexanone was dropped onto the painted surface using a dropper, and changes in the painted surface after standing for 1 hour were examined.

Claims (1)

[Claims] 1. A resin solution dissolved in an organic liquid is mixed with an alcohol dispersion of colloidal silica, and then the alcohol is distilled off to stabilize the dispersion of colloidal silica with the resin solution. A method for producing a colloidal silica-containing resin composition. 2. A colloidal silica-containing resin composition comprising colloidal silica dispersed in a resin solution dissolved in an organic liquid.