JPS6030350B2 - Method for stabilizing coating compositions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stabilizing coating compositions with excellent surface hardness, abrasion resistance, flexibility, dyeability, etc.

Plastic molded products are used in large quantities due to their advantages such as light weight and impact resistance, but on the other hand, they have drawbacks such as insufficient hardness, easy to get wet with hot water, and easy to be eroded by solvents.
Furthermore, inorganic glass is widely used in eyeglass lenses due to its advantages such as chemical resistance and surface hardness, but on the other hand, it has disadvantages such as lack of dyeability, making it unfashionable. As a means for improving the above-mentioned drawbacks, for example, a method is known in which plastic molded articles, inorganic glass, etc. are coated with a coating composition having high hardness, abrasion resistance, flexibility, and dyeability.

However, the above-mentioned coating composition has a serious problem in that it has a short stability during coating, that is, it has a short shelf life.
Extending the shelf life of a coating composition is important not only because it contributes to cost reduction, but also because it makes it possible to reduce product variation.

The term "handling time" here means the time during which the coating composition can be used after it has been prepared without being substantially changed and without causing any practical problems. In other words, it determines the cost of the coating.

The present inventors have conducted intensive studies to improve the above-mentioned drawbacks of coating compositions, and as a result, have arrived at the present invention described below.

That is, the present invention provides a coating composition comprising the following components: 'B', 'C} and Hydrolyzate of silane compound.

[B} Aluminum chelate compound represented by the general formula N.Xn.Y3-n.

Here, X is a lower alkoxy group, Y is the general formula MICOCH
2COM2 is MCOCH
2COOM4, (M1, M2, M, M4 are lower alkyl groups), and n is 0, 1 or 2.

[C} Silica fine particles with an average particle size of about 1 to 100 hours.

'D} Multidentate compound. A method for stabilizing a coating composition, which comprises adjusting the pH of the coating composition to 5.0 to 7.5.

The pH of the above-mentioned coating composition consisting of (mother, [C} and support component) is usually less than 5.0 degrees Celsius or more than 8.0.

Therefore, for the purposes of the present invention, the P of the coating composition is
H is 5.0 to 7.5, more preferably 6.0 to 7.0
It is necessary to adjust the By adjusting the pH of the coating composition within the above-mentioned range, it is possible to significantly extend the shelf life, reduce costs, and improve productivity.

Here, extending the workability time does not simply mean stabilizing coating workability by maintaining the characteristic values of the coating composition;
It also means stabilizing the performance of the coating film after storage over time or continuous use.

That is, it refers to the effect that the surface hardness (abrasion resistance and dyeability), which are characteristics of the coating film obtained from the present composition, can be stably obtained even after long-term storage or use of the composition.

In particular, the coating composition of the present invention is effective in stabilizing the stainability, which changes even if the characteristic values of the composition (for example, viscosity) do not change. As the pH regulator of the present invention, various acidic or salty substances can be used. Specific examples of these substances include organic carboxylic acids such as formic acid, acetic acid, (meth)acrylic acid and their polymers, or inorganic acids such as phosphoric acid and sulfuric acid, Lewis acids, and even sodium acetate, lithium acetate, and acetic acid. Alkali metal salts or alkali metal salts of various carboxylic acids such as calcium, amines such as ammonia, methylamine, pyridiso, phenasotroline, etc., various acids such as sodium aluminate, sodium thiosulfate, caustic soda, caustic potash, calcium hydroxide, etc. , bases, acid salts, basic salts can be used.

In the present invention, the pH can be adjusted by adding various adjusting agents dissolved in water, alcohol, etc., or directly adding the adjusting agent.

Moreover, the timing of addition is not an essential problem, but it is important to finally adjust the pH of the coating composition to 5.0 to 7.5. Next, each component forming the coating composition of the present invention will be explained.

(2) A hydrolyzate of a silane compound having at least one epoxy group and two or more alkoxy or acyloxy groups bonded to a silicon atom in its molecule, which is a component, is defined by the general formula or (where RI is C, ~ C6 alkyl, alkoxyalkyl, acyl, R2 is C, ~C6 alkyl, halogenated alkyl, aryl or halogenated aryl, R
3 is hydrogen or methyl group, n is 2 or 3, a is 1-6
, b is 0-2, R4 is C, -C6 alkyl, alkoxyalkyl, acyl, R5 is C, -C6 alkyl, halogenated alkyl, aryl or halogenated aryl, m is 2 or 3.

) is a hydrolyzate of the compound represented by

Specific representative examples of such compounds include y-glycidoxypropyltrimethoxysilane, y-glycidoxypropyltriethoxysilane, y-(8-glycidoxyethoxy)propyltrimethoxysilane, and y-glycidoxypropyltrimethoxysilane. xypropylmethyldimethoxysilane, y-glycidoxypropylmethyldiethoxysilane, y-glycidoxypropylphenyldimethoxysilane, 8-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 8-(
Examples include 3,4-epoxycyclohexyl)ethyltriethoxysilane. As the aluminum chelate compound represented by the general formula AI・Xn・Y3-n, which is the 'B} component of the present invention, various compounds can be mentioned, but the solubility in the coating composition, the effect as a curing catalyst, etc. Particularly preferred from this point of view are aluminum acetylene acetonate, aluminum bisethyl acetoacetate monoacetylacetonate, aluminum di-n-butoxide monoethylacetoacetate, aluminum di-iso-propoxide monomethyl acetate, and the like.

It is also possible to use a mixture of two or more of these. The average particle size used as the 'C} component of the present invention is about 1
As the silica fine particles of ~100, it is also possible to use hydrophilic or hydrophobic dry powders produced by combustion of purified silicon tetrachloride, but particularly effective for the present invention are those generally called "silica sol". It is a colloidal solution in which high molecular weight silicic acid anhydride is dispersed in water and/or an organic solvent such as alcohol. Further, silica fine particles whose surfaces are treated or coated with various organic substances for the purpose of improving dispersibility can also be included. For purposes of the present invention, an average particle size of about 1 to 100 mm is preferably used, with a particularly preferred particle size of about 5 to 50 mm.

The polydentate compound that is the {D} component of the present invention refers to a compound that functions as a polydentate ligand, and is a compound that functions as a polydentate ligand. A compound having two or more atoms.

Specific examples of such compounds include siketones such as acetylacetone, ketoesters such as methyl acetoacetate and ethyl acetoacetate, keto alcohols such as salicylaldehyde, dicarboxylic acids such as oxalic acid, 2,2'-bipyridine, 1,10 -Phenant.

Examples include cyclic amines such as phosphorus. In addition to the above-mentioned components, various compounds can be added to the coating composition of the present invention depending on the purpose or use.
Specific examples include organic silicon compounds, epoxy resins, and organic polymers other than the above components.

Examples of organosilicon compounds include tetraalkoxysilanes such as methyl silicate, ethyl silicate, i-propyl silicate, n-propyl silicate, n-butyl silicate, sec-butyl silicate and t-butyl silicate, methyltrimethoxysilane, and methyltriethoxy. Silane, methyltrimethoxyethoxysilane, ethyltrimethoxysilane, methyltriacetoxysilane, ethyltriethoxysilane, pinyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxyethoxysilane, vinyltriacetoxysilane, phenyltrimethoxysilane, y-chloropropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, y-methacryloxypropyltrimethoxysilane, y-mercaptopropyltrimethoxysilane, B
- Trialkoxy or triacyloquine silanes such as cyanoethyltriethoxysilane, dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, y-chloropropylmethyldimethoxysilane, dimethyldiacetoxysilane, y-methacryloxypropylmethyl Examples include dialkoxysilanes or diacyloxysilanes such as dimethoxysilane, y-mercaptopropylmethyldimethoxysilane, and methylvinyldimethoxysilane.

Component (1) of the present invention and the hydrolyzate of the above-mentioned silane compound are prepared by adding pure water or an acidic aqueous solution such as hydrochloric acid or sulfuric acid.
Manufactured by worshiping a hawk.

During hydrolysis, alcohol, alkoxy alcohol, organic carboxylic acids such as acetic acid, etc. are produced, so hydrolysis can be carried out without a solvent.

Furthermore, the silane compound can be mixed with a suitable solvent and then hydrolyzed. Depending on the purpose, it is also possible to use the product after hydrolyzing it without a solvent and removing an appropriate amount of the resulting alcohol, alkoxy alcohol, or organic carboxylic acid such as acetic acid, and water under heating and/or reduced pressure. However, it is also possible to substantially replace the solvent by subsequently adding a suitable solvent. As the solvent, various solvents such as alcohols, esters, ethers, ketones, halogenated hydrocarbons, and aromatic solvents such as toluene can be used depending on the purpose, and mixed solvents can also be used if necessary. Examples of epoxy resins are those that are widely used in paints, casting, etc., such as polyolefin epoxy resins synthesized by peroxidation method, cyclobentadiene oxide, cyclohexene oxide, hydrogenated bisphenol A, or hexahydro. Alicyclic epoxy resins such as polyglycidyl ether or polyglycidyl ester obtained from phthalic acid and epichlorohydrin, polyhydric phenols such as vinphenol A, bisphenol F, catechol, and resorcinol; Poly)ethylene glycol, (poly)propylene glycol, neobentyl glycol, glycerin, trimethylolpropane, bentaerythritol,
Polyglycidyl ethers obtained from polyhydric alcohols such as diglycerol and sorbitol and epichlorohydrin, epoxidized vegetable oils, epoxy novolaks obtained from novolac type phenolic resins and epichlorohydrin, phenolphthalein and epichlorohydrin and copolymers of glycidyl methacrylate and acrylic monomers such as methyl methacrylate or styrene.

Examples of organic polymers include hydroxyl group polymers such as polypinyl alcohol, cellulose acetate butyrate, polyhydroxyethyl methacrylate, and hydroxyethylcellulose, polypinyl acetate, and copolymers of acrylic esters and/or methacrylic esters (among them (including copolymers with other vinyl monomers), polyamides, polyesters, and various amino resins (including melamine resins, urea resins, etc.). Next, the addition ratio of each of the above components will be explained. First, the amount of component 'C) added is 0.01 to 5 parts by weight per 1 part by weight of the component.
Preferably, the amount is from 0.1 to 2 parts by weight; if the amount is less than this, the effect of addition will be 4.5%, and if it is more than this, defects such as cracks will occur. Further, the amount of component 'B} to be added is suitably 0.1 to 10 parts by weight, particularly preferably 0.5 to 5 parts by weight, per 10 parts by weight of the total of component 'B'. If the amount is too high, the curing will be insufficient, while if it is more than this, defects such as purulence or decreased transparency of the resin will occur.

Furthermore, the amount of the component (component) in the present invention, that is, the compound forming a polydentate ligand, is 0.01 mol or more, preferably 0.01 mol or more, per 1 mol of the aluminum chelate compound of component (B).
Use 1 mole or more.

The upper limit of the amount used depends on the coating workability of the paint (solid content decreases)
It is determined by the effect on the base material (particularly in the case of plastic base materials, the base material may be eroded by solvents). It is also possible to use a surfactant in the coating composition of the present invention for the purpose of improving the flow during application, improving the smoothness of the coating film, and lowering the coefficient of friction of the coating film surface. Block or graft copolymers of dimethylsiloxane and alkylene oxide are effective.

In addition, it is easy to disperse dyes and pigments and fillers, dissolve organic polymers, color the coating, and improve the practicality of the coating agent by improving its applicability, adhesion to substrates, and physical properties. possible. It is also easily possible to add an ultraviolet absorber for the purpose of roughly improving the aging resistance, and an antioxidant to improve the heat deterioration resistance.

The objects to be coated with the coating composition of the present invention include polymethyl methacrylate and copolymers thereof, acrylonitrile styrene copolymer, polycarbonate, cellulose acetate, polyvinyl chloride, polyethylene terephthalate, epoxy resin, and Plastic molded products such as saturated polyester resin, CR-39 (diethylene glycol bisallyl carbonate polymer),
Examples include films, inorganic glass, wood, metal articles, and paper.

As a coating means, commonly used coating methods such as brush coating, dip coating, roll coating, spray coating, and flow coating can be easily used.

It is also possible to apply the present composition to a mold and then polymerize the base material raw material, or to complete heat curing by bringing the plastic base material coated with the present composition into close contact with the mold. The composition of the present invention is mainly cured by heat treatment, and the heating temperature and time should be determined depending on the coating substrate to be treated and the required performance.

The coating composition obtained by the present invention as described above has a sufficiently long shelf life and high production efficiency.

Furthermore, the coating film or molded product obtained using the composition of the present invention is transparent, has excellent hardness, especially scratch resistance, hardly gets scratched even when rubbed strongly with hard materials such as steel wool, and can be dyed with disperse dyes. such as,
No deterioration in appearance due to scratches during use, which has traditionally been a problem with plastic molded products.
Furthermore, since it enables dyeing without reducing the surface hardness of inorganic glass, it can be applied to the production of articles with extremely high commercial value. Examples 1 to 5, Comparative Examples 1 to 5 [1' Preparation of silane hydrolysis 6.3 molar particles of y-glycidoxypropylmethyldiethoxysilane were charged into a reactor equipped with a rotor, and the liquid temperature was lowered. 1o
While keeping it at o0 and fixing it with a magnetic stirrer,
55.8 g of a 0.05N aqueous hydrochloric acid solution was gradually added dropwise.

After completion of the dropping, 207.7 kg of y-chloropropyltrimethoxysilane was further mixed, and 55.7 kg of a 0.01N aqueous hydrochloric acid solution was added.
Gradually drip over 6.5 days. After the dropwise addition was completed, cooling was stopped to obtain a silane hydrolyzate. (2) Preparation of Paint The above-mentioned silane hydrolyzate 606 methanol silica sol (product of Nissan Chemical Co., Ltd., average particle size 13±1, solid content 30%) 1354.3 yen, diethylene glycol dimethyl ether 103 yen, methanol 791.3 yen. After 6 days, 4.5 times of a silicone surfactant was added and mixed while stirring.

Add 40% of aluminum acetylacetonate to this mixture.
6 minutes was further added and mixed, and the mixture was thoroughly mixed. This mixture 2
Acetylacetone was added in the amount shown in Table 1 to a 25-meter tank, and the added amount was adjusted with sodium acetate so that the pH became the value shown in Table 1, respectively, to prepare a paint. As a comparative example, a test was also carried out without pH adjustment. [
3} Performance test of painted and painted products Dethylene glycol bisallyl carbonate polymer resin (diameter 75
Skin, thickness 2.1 Misaki, Riken Lens Industry Co., Ltd. product, CR
-39 plano lens) by dipping method.

The coating conditions were a pulling rate of 1 ratio/min, and a 9yo
It was heated and cured in a hot air dryer for 4 hours.

Each paint was tested immediately after preparation and after being stored for two weeks at 23rd grade. The test results are shown in Table 1. The painted lenses were also tested using the dyeability test described below. '4} Dyeability test method A disperse dye was used as the dye.

The names of the dyes and the amounts added are as follows. Miketon Polyester Red 48F O. 8125 Yu (Mitsui Tosho Co., Ltd. product) Diamonds Yellow 9R1E
O. 4375 yen (Mitsubishi Kasei Co., Ltd. product) Chikara Yaron Polyester Fluoru TS 3.750 yen (Nippon Kayaku Co., Ltd. product) After putting each of the above dyes into the beaker, Rapizol B-80 (Nippon Oil Co., Ltd. product)
6 hours were added.

After that, add 10 minutes of water and mix well with a glass rod. Thereafter, the above dye was further dispersed and dissolved in warm water of about 80 q○ overnight to obtain a dye. After dyeing at 80° C. for 13 minutes using this dyeing bath, the total light transmittance of the dyed lens was measured. Table 1

Claims (1)

[Scope of Claims] 1. A coating composition comprising the following components (A), (B), (C) and (D), the pH of which is adjusted to 5.0 to 7.5. Stabilization method. (A) A hydrolyzate of a silane compound having in its molecule at least one epoxy group and two or more alkoxy or acyloxy groups bonded to a silicon atom. (B) An aluminum chelate compound represented by the general formula Al.X_n.Y_3_-_n. Here, X is a lower alkoxy group, Y is the general formula M^1CO
OCH_2COM^2 or M^3COCH_2C
OOM^4, (M^1, M^2, M^3, M^4 are lower alkyl groups) is at least one ligand selected from the compound represented by OOM^4, where n is 0, 1 or It is 2. (C) Fine silica particles with an average particle diameter of about 1 to 100 mμ. (D) Multidentate compound.