JPS6221030B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to coating compositions that form coatings with excellent scuff resistance, flexibility, dyeability and durability. Plastic molded products are used in a wide range of applications due to their advantages such as light weight, easy workability, and impact resistance, but one of their major drawbacks is that they have low surface hardness and are easily scratched. This deficiency is particularly serious in areas where plastics are widely used and require transparency. For example, in applications such as lenses and windows, it is more easily scratched than ordinary glass. To solve this problem, it has been proposed to cover with a coating material that has good scratch resistance. Typical examples include coating materials made by heating and curing various silicone resin compositions, particularly silane compounds with or without various functional groups, such as hydrolysates of tetraalkoxysilanes and trialkoxyalkylsilanes. Among these, a composition for coating materials that can improve surface hardness, can be dyed with disperse dyes, and has good bending resistance has been reported (Japanese Patent Application Laid-Open No. 1983-1971).
-112698, Japanese Unexamined Patent Publication No. 111336/1983). Although this composition has a certain degree of stability when applied, improving the stability has become an important issue both from an economical point of view and for product stabilization. In particular, dyeing properties are an important issue in various lens applications that require high fashionability, and variations in paint quality can have a subtle effect on dyeing properties. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a coating composition which provides a highly stable, scratch-resistant, flexible and dyeable coating. The present invention is a coating composition comprising components A, B and C below and further comprising component D below. A Hydrolyzate of a silane compound having at least one epoxy group and two or more alkoxyl groups bonded to a silicon atom in the molecule B An aluminum chelate compound represented by the general formula Al・X _o・Y _3-o (wherein where X is a lower alkoxyl group, Y is M ¹ COCH ₂ COM ² and
Ligands derived from compounds selected from the group consisting of M ³ COCH ₂ COOM ⁴ (M ¹ , M ² , M ³ and M ⁴
is a lower alkyl group), and n is 0, 1 or 2. ) C Multidentate compound D At least one compound selected from the following group (i) Hydrolyzate of a compound represented by Ra ¹ Rb ² SiZ _4-(a+b) (where R ¹ , R ² is alkyl, alkenyl, aryl, methacryloxypropyl or halogenated alkyl, Z is an alkoxyl group or acyloxy group, a and b are each 0, 1 or 2, and a+b is 0, 1 or 2). (ii) Polyfunctional epoxy compound The composition of the present invention may further contain the following component E, which is preferable as a method for improving scuff resistance. E Fine particulate silica having an average particle diameter of about 1 to 100 mμ As the compound forming the hydrolyzate of component A, preferably a compound represented by the following general formula is used. (where R ³ is an alkyl or alkoxyalkyl group having 1 to 4 carbon atoms, R ⁴ is 1 to 6
an alkyl or aryl group having carbon atoms of
R ⁵ is hydrogen or methyl group, m is 2 or 3, a
is an integer from 1 to 6, and b is 0, 1 or 2. ) Examples of these compounds include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-glycidoxypropylmethyldimethoxysilane.
Examples include (3,4-epoxycyclohexyl)ethyltrimethoxysilane. Although various compounds can be used as the aluminum chelate compound of component B, the following compounds are preferred from the viewpoints of catalytic activity, solubility in the composition, and stability. Specifically, they include aluminum acetylacetonate, aluminum ethyl acetoacetate bisacetylacetonate, aluminum bisethylacetoacetate acetylacetonate, aluminum di-n-butoxide monoethylacetoacetate, aluminum di-i-propoxide monomethylacetoacetate, and the like. Mixtures of these compounds can also be used. The polydentate compound of component C refers to a compound that functions as a polydentate ligand, and has two or more coordination atoms that directly bond to the central atom (transition metal or non-transition metal) during complex formation. It is. Specific examples of such compounds include diketones such as acetylacetone, ketoesters such as methyl acetoacetate and ethyl acetoacetate, keto alcohols such as salicylaldehyde, carboxylic acids such as oxalic acid, 2,2'-bipyridine, 1, 10−
Examples include cyclic amines such as phenanthroline. Compounds forming the hydrolyzate of (i) in component D include methyl silicate, ethyl silicate, i
- Tetraalkoxysilanes such as propyl silicate, n-propyl silicate, n-butyl silicate, sec-butyl silicate and t-butyl silicate, methyltrimethoxysilane,
Trialkoxy or triacyloxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, and 3,3,3-trifluoropropyltrimethoxysilane Examples include dialkoxysilanes such as dimethyldimethoxysilane and methylphenyldimethoxysilane. Furthermore, mixtures of these can also be used. The polyfunctional epoxy compound (ii) in component D is widely used as a coating material and a molding material. As these compounds, polyglycidyl ethers or polyglycidyl esters are preferred. The polyglycidyl ether is preferably a reaction product between a polyfunctional phenol and epichlorohydrin, or a reaction product between an aliphatic or alicyclic polyhydric alcohol and epichlorohydrin, and has a molecular weight of 1000 or less. An example is 2,2-di(p-hydroxyphenyl)propane (bisphenol-
A), di(p-hydroxyphenyl)methane (bisphenol F), and the like. The aliphatic or alicyclic polyhydric alcohol used therein is preferably an alcohol having 20 or less carbon atoms. These alcohols include (poly)ethylene glycol, (poly)propylene glycol, neopentyl glycol, glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerol,
Examples include sorbitol, 1,4-dihydroxymethylcyclohexane, and hydrogenated bisphenol-A. Preferred polyglycidyl esters are reaction products of aliphatic, cycloaliphatic and aromatic polybasic acids having up to 8 carbon atoms with epichlorohydrin, and polybasic acids used in these reactions include succinic acid, glutaric acid, etc. Acid, adipic acid, tetrahydrophthalic acid, hexahydrophthalic acid, hexahydroterephthalic acid, phthalic acid, isophthalic acid,
Examples include terephthalic acid. These polyfunctional epoxy compounds can be used alone or as a mixture. In order to improve the hardness and prevent scratches, it is preferable to use silica fine particles as component E. An effective example of the silica fine particles is silica sol. Silica sols are colloidal dispersions of high molecular weight silicic anhydride in water and/or organic solvents such as alcohols. For the purpose of this invention, particles having an average particle diameter of usually about 1 to 100 mμ, particularly about 5 to 30 mμ are preferred. The silane hydrolyzates of component A and component D(i) described above can be obtained by hydrolyzing the silane compound with pure water or a dilute aqueous solution of hydrochloric acid or sulfuric acid. Hydrolysis can also be carried out without using a solvent, using only the alcohol or carboxylic acid produced during the reaction of water and silanes. It is also possible to add or replace other solvents. When hydrolyzing two or more types of silanes, it is possible to hydrolyze each silane separately and then mix them, but there is also a method of co-hydrolyzing a mixed silane, and then hydrolyzing one silane and then hydrolyzing the other. It is also possible to apply a sequential hydrolysis method in which silane is added to this and hydrolysis is continued. Component B, that is, the aluminum chelate compound, is about 0.01 part by weight per 100 parts by weight of the above component A (including components D and E, if present).
~50 parts by weight is a preferred amount. The amount of component C, that is, the compound forming a polydentate ligand, is 0.01 mol or more, preferably 0.1 mol or more per 1 mol of component B, the aluminum chelate compound. The upper limit of the amount used is determined by the paint workability (reduction in solids content) and the effect on the base material (particularly in the case of plastic base materials, the base material may be eroded by the solvent). The amount of component D is not particularly limited, but if dyeability is required, the calculated solid content of component A in component A and component D is 10% or more, and each of component A and component D (ii) It should be selected so that it is at least 30% of the sum of the calculated solid weights. Here, the calculated solid weight W of the hydrolyzate (component A and component D(i)) is the weight of the silane compound Q _k Si (OS) _4-k (molecular weight is M ₀ ) used before hydrolysis. If W ₀ , then it is the quantity defined by the following equation. W=W ₀ ·M ₁ /M ₀ where M ₁ is the formula quantity of Q _k SiO _(4-k)/2 . Note that Q and S mean corresponding organic groups in the silane compounds used in component A and component D(i) described above, and k is 0, 1 or 2. The calculated solid weight of component D(ii) is the amount used. Component E is preferably used in an amount of 500 parts by weight or less, preferably 200 parts by weight or less, per 100 parts by weight of components A and C. If the amount of component E is small, the hardness tends to be low, but if it is too large, coating film defects such as cracking will occur. A variety of solvents can be used in the coating compositions described above. This solvent is appropriately selected depending on the coating method, heating method, type of substrate, etc. of the substrate to be used, but it should contain water of about 1% or more, preferably about 2% or more by weight. Its inclusion is important in stabilizing the coating composition. The moisture in the coating composition may be present due to insufficient hydrolysis of the silanes, may be generated by a condensation reaction of a hydrolyzed product of the silanes, or may be added separately from outside the system. Various other additives can be added to the composition of the present invention. For example, various surfactants are effective for controlling the fluidity of the coating film during the coating stage, increasing the surface smoothness, and reducing the coefficient of friction of the surface. Examples of these effects include graft copolymers of dimethylsiloxanes with alkylene oxides. Furthermore, ultraviolet absorbers, antioxidants, etc. can be used, and colorants such as pigments and dyes and/or fillers can also be used. Various organic polymers can be used to improve coating properties, adhesion, and paintability. The substrates used to obtain the articles coated with the coatings of the present invention can be of various materials, but plastic products, particularly the substrates described below, are suitable. That is, acrylic polymers, especially polymethyl methacrylate, poly(2,2-dihydroxydiphenylpropane) carbonate, diethylene glycol bisallyl carbonate polymers,
Examples are polyesters, especially polyethylene terephthalate, acrylonitrile/styrene copolymers, acrylonitrile/butadiene/styrene copolymers. In addition to the above-mentioned plastic products, inorganic glass, wood and metal can also be used, but the transparency, which is a characteristic of the coating material of the present invention,
Plastic products are suitable for taking advantage of their scratch resistance and flexibility. Particularly suitable are sunglasses, corrective or safety eyeglass lenses, goggles, sun visors, watch covers, display cases, nameplates, various lighting equipment, mirrors, etc. As the coating method, a commonly used coating method can be applied. For example, dip coating, spin coating, roll coating, curtain flow coating and spray coating can be applied. Curing of the coating composition is accomplished by heating.
The applicable temperature is limited depending on the base material used, but
A range of 50-250°C gives good results. The coating composition obtained as described above has very good stability. Changes in the coating composition are most sensitively reflected by changes in the epoxy value in the composition and changes in the dyeability of the cured coating film. As described in the Examples, it can be seen that the present composition exhibits superior stability compared to a system containing no polydentate ligand-forming compound. Comparative Examples 1 and 2; Example 1 (1) Preparation of γ-glycidoxypropylmethyldiethoxysilane hydrolyzate 386.3 g of γ-glycidoxypropylmethyldiethoxysilane was charged into a reactor equipped with a rotor. , while keeping the liquid temperature at 10℃ and stirring with a magnetic stirrer, add 0.05N hydrochloric acid aqueous solution 55.8
Gradually add g. The time required for dropping was 83 minutes. After dropping, stop cooling and
- A hydrolyzate of glycidoxypropylmethyldiethoxysilane was obtained. (hereinafter abbreviated as H-GMS). The properties of the obtained solution are epoxy equivalent: 306
It was hot. (2) Preparation of composition for basic study The above H-GMS, aluminum acetylacetonate, and acetylacetone were mixed in the proportions shown in Table 1, and 137 g of ethanol was added to each to form a composition for basic study. did. (3) Stability test The changes in epoxy equivalent when each of the paints described in the previous section were left in a constant temperature dryer at 40°C for various times were investigated. For Comparative Example 2 and Example 1, the dyeability after 4 days was also tested. The results are shown in Table 1. The test method was as follows. (a) Measurement of epoxy equivalent This was carried out according to the hydrochloric acid-dioxane method. (b) Application and evaluation Comparative example 2 and Each paint of Example 1 was applied. The coating conditions were a pulling rate of 10 cm/min, and the coating was further heated and cured in a hot air dryer at 93° C. for 4 hours. The painted lenses were dyed by the method described below, and the dyeability was measured and evaluated. A disperse dye was used as the dye. Miketon Polyester Red 4BF (Mitsui Toatsu Co., Ltd. product) 0.8125g, Dianex Yellow 5R-
Put 0.4375 g of E (Mitsubishi Kasei Co., Ltd. product) and 3.750 g of Kayalon Polyester Blue TS (Nippon Kayaku Co., Ltd. product) into a 1-liter beaker, and add 6 g of Rapizol B-80 (NOF Co., Ltd. product). After that, add 10g of water and mix well with a glass rod. Then another 80
A dyeing bath was prepared by dispersing and dissolving the above dye in 1 liter of warm water at around 10°C. Using this dye bath,
Staining was carried out at 80°C for 13 minutes. The total light transmittance of the dyed lens was measured.

[Table] Examples 2 to 7, Comparative Example 3 (1) Preparation of silane hydrolyzate 207.7 g of γ-chloropropyltrimethoxysilane was mixed with 441.8 g of H-GMS of Example 1,
Keep the liquid temperature at 10℃. While stirring, 56.5 g of 0.01N hydrochloric acid aqueous solution was gradually added dropwise. The time required for dropping was 38 minutes. After the dropwise addition was completed, cooling was stopped to obtain a silane hydrolyzate. The properties of the obtained solution are epoxy equivalent: 496, viscosity (10℃)
It was 10.1cps. (2) Preparation of paint To 606 g of the above hydrolyzate, add 1354.3 g of methanol-dispersed colloidal silica (“Methanol Silica Sol” manufactured by Nissan Chemical Co., Ltd., solid content 30%), 103 g of diethylene glycol dimethyl ether, 791.6 g of methanol, and silicone surfactant. 4.5 g was added and mixed while stirring. 40.6 g of aluminum acetylacetonate was added to this mixed solution, and acetylacetone was added in an amount shown in Table 2 to 50 parts by weight of this mixed solution to prepare a paint. (3) Performance test of coatings and coated products The coatings described in the previous section were applied and heat-cured according to the coating method described in Example 1 immediately after preparation and after being left in a constant temperature dryer at 40°C for 64 hours. . The following tests were conducted on the painted lenses. (b) Adhesion test Draw 11 parallel lines on the coating surface at equal intervals of 1 mm,
Draw the same number of parallel lines that intersect at right angles to these to make 100 squares. These lines cut through the coating to the extent that they reach the substrate. A cellophane adhesive tape (trade name: "Cello Tape", manufactured by Nichiban Co., Ltd.) was strongly applied on top of the goblets and then rapidly peeled off in a 90-degree direction to examine whether or not the paint film had peeled off. (b) Abrasion resistance Rub with steel wool #0000 and check for scratch resistance. Judgment was made as follows. A...No scratches even with strong friction B...Slight scratches occur with very strong friction C...Scratch occurs even with weak friction. The diethylene glycol bisallyl carbonate polymer lens, which was not coated at all, was rated C. (c) Dyeability The same procedure as in Example 1 was carried out. The test results are shown in Table 2. As a comparative example, Table 2 also shows the results when acetylacetone was not added.

[Table] Examples 8 to 13, Comparative Example 4 (1) Preparation of paint To 720 g of H-GMS prepared in Example 1, “Epicote 827” (manufactured by Ciel Chemical Co., Ltd., with an epoxy equivalent of approx.
185) 158.4g, “Epicote 834” (manufactured by Ciel Chemical, epoxy equivalent: approx. 250), “Denacol
Ex320” (manufactured by Nagase Sangyo Co., Ltd., epoxy equivalent approximately 130,
trimethylolpropane polyglycidyl ether) 126.5g, diacetone alcohol 383.4g,
Add 193.1 g of benzyl alcohol and 6.8 g of silicone surfactant, mix well and dissolve, then add 2733.8 g of methanol silica sol with stirring. To this mixed solution, 82.4 g of aluminum acetylacetonate was added, and to 100 parts by weight of this mixed solution, acetylacetone was added in the amount shown in Table 3 to prepare a paint. (2) Performance test of coatings and coated products The following tests were conducted on each of the coatings described in the previous section immediately after manufacture and after being placed in a constant temperature dryer at 40°C for 30 hours. That is, each of the above paints was applied to a polycarbonate lens (diameter 60 mm, thickness 3.0 mm, General-
It was coated on "Lexan-141" (manufactured by Electric Co., Ltd.) using a dipping method at a pulling rate of 10 cm/min, and was heated and cured in a hot air dryer at 130°C for 2 hours. The coated lenses were subjected to only the adhesion test and abrasion resistance test described in Examples 2-7. The test results are shown in Table 3. Note that Table 3 also shows the results of Comparative Example 4 in which acetylacetone was not added.

[Table] Examples 14 to 16, Comparative Example 5 Paints were prepared in which the polydentate ligands and amounts added of acetylacetone in Example 2 were changed as shown in Table 4. Immediately after each paint is manufactured and
After being left at 20° C. for one week, coating and performance evaluation were performed according to Example 2. The results are shown in Table 4. Furthermore, as Comparative Example 5, the results obtained when no polydentate ligand was added are also shown in Table 4.

【table】

Claims (1)

[Scope of Claims] 1. A coating composition characterized by containing the following components A, B and C. A Hydrolyzate of a silane compound having at least one epoxy group and two or more alkoxyl groups bonded to a silicon atom in the molecule B An aluminum chelate compound represented by the general formula Al・X _o・Y _3-o (wherein where X is a lower alkoxyl group, Y is M ¹ COCH ₂ COM ² and
Ligands derived from compounds selected from the group consisting of M ³ COCH ₂ COOM ⁴ (M ¹ , M ² , M ³ and M ⁴
is a lower alkyl group), and n is 0, 1 or 2. ) C Polydentate Compound 2 A coating composition characterized by containing the following components A, B, C and D. A Hydrolyzate of a silane compound having at least one epoxy group and two or more alkoxyl groups bonded to a silicon atom in the molecule B An aluminum chelate compound represented by the general formula Al・X _o・Y _3-o (wherein where X is a lower alkoxyl group, Y is M ¹ COCH ₂ COM ² and
Ligands derived from compounds selected from the group consisting of M ³ COCH ₂ COOM ⁴ (M ¹ , M ² , M ³ and M ⁴
is a lower alkyl group), and n is 0, 1 or 2. ) C Multidentate compound D At least one compound selected from the following group (i) Hydrolyzate of a compound represented by Ra ¹ Rb ² SiZ _4-(a+b) (where R ¹ , R ² is alkyl, alkenyl, aryl, methacryloxypropyl or halogenated alkyl, Z is an alkoxyl group or acyloxy group, a and b are each 0, 1 or 2, and a+b
is 0, 1 or 2. ) (ii) Polyfunctional epoxy compound