JPS624060B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition for a coating material for polycarbonate molded articles having excellent scratch resistance, flexibility, transparency and durability. Plastic molded products are used in a wide range of applications, taking advantage of their advantages such as light weight and easy processability. Among them, polycarbonate (poly-2,2-di(p-hydroxyphenylpropane carbonate is a typical example)) resin is used in safety glasses, safety glass, household appliances, and medical appliances due to its excellent impact resistance. However, as with plastic products in general, this polycarbonate resin in particular has a low surface hardness and is easily scratched even when wiped with gauze.
For this reason, although it is extremely effective from the standpoint of safety because it is difficult to break, it has only been found to have limited uses in applications such as glasses and windows. In order to solve these problems, attempts have been made to apply scratch-resistant coatings to the surfaces of plastic products, and many proposals have been made. A typical example is one using a silicone-based highly hardened coating material. However, when this paint is applied to polycarbonate resin, there is a problem of low adhesion.
In particular, it has poor durable adhesion and easily peels off even during short-term accelerated weathering tests. A known example close to the present invention is JP-A-53-111336.
There is a technology in the publication. This technology is a coating composition consisting of a hydrolyzate of epoxysilane or epoxysilanol, an epoxy resin, silica fine particles, and an aluminum catalyst. However, with this technology, the mixing ratio of the epoxy silane hydrolyzate and the epoxy compound is not optimized;
Also, because the epoxy equivalent of the epoxy compound was not optimized, the compatibility of the paint was poor,
There were drawbacks such as clouding of the paint film. The object of the present invention is to provide a scuff-resistant coating that has good adhesion to polycarbonate resins without any pretreatment. Another object of the present invention is to provide a coating material that has good flexibility so that it can be worked on without causing defects such as cracks on the coating surface even when framed as an eyeglass lens. It is in. Yet another object of the present invention is to provide a coating material with excellent transparency that is suitable for applications requiring transparency such as safety lenses and window glasses. The above object is achieved by the present invention described below. That is, the present invention comprises the following components A, B, and C.
and D, and the mixing ratio of components A and B is
A coating composition for a polycarbonate molded article, characterized in that the solid content weight ratio is (component B)/(component A+component B) = 0.1 to 0.8. A Hydrolyzate of γ-glycidoxypropylmethyldialkoxysilane and/or hydrolyzate of γ-glycidoxypropyltrialkoxysilane B Epoxy compound having the following structural formula with an epoxy equivalent of 400 or less (Here, R ₁ , R ₂ and R ₃ are H or CH ₃ ,
n is an integer greater than or equal to 0. ) C Fine particulate silica with an average particle diameter of about 1 to about 100 mμ D Aluminum chelate compound represented by the general formula Al・Xn・Y _3-o (where X is a lower alkoxyl group, Y is
A ligand derived from a compound selected from the group consisting of M ¹ COCH ₂ COM ² and M ³ COCH ₂ COOM ⁴ (M ¹ , M ² , M ³ and M ⁴ are lower alkyl groups), n is 0, 1 or It is 2. ) The compound that produces the hydrolyzate of component A is a compound represented by the following general formula. Here, n is 0 or 1, and R is an alkyl or alkoxyalkyl group having 1 to 4 carbon atoms. Specific examples of these include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltributoxysilane, and γ-glycidoxypropyltri(β-ethoxy-ethoxy). Silane, γ-glycidoxypropylmethyldimethoxysilane, γ-
glycidoxypropylmethyldiethoxysilane,
Examples include γ-glycidoxypropylmethyldibutoxysilane and γ-glycidoxypropylmethyldi(β-ethoxy-ethoxy)silane.
These can be used alone or in combination of two or more. Examples of component B include a condensate of bisphenol A and epichlorohydrin, a condensate of bisphenol F and epichlorohydrin, and a condensate of bisphenol A and methylepichlorohydrin. These epoxy equivalents need to be 400 or less; if they are larger than this, the compatibility with other components will be poor and the coating will become cloudy. This component is mainly involved in the adhesion between the polycarbonate resin and the coating film. In the case of conventional silicone-based hardening materials, the epoxy resin does not harden at temperatures that can be applied to polycarbonate, so it cannot be blended to a level sufficient to impart adhesion.However, in the present invention, the epoxy resin can also be hardened. Get involved and get good results. Two or more of these epoxy resins can be used in combination, even if they have different epoxy equivalents. An effective example of fine silica particles as component C is silica sol. Silica sols are colloidal dispersions of high molecular weight silicic anhydride in organic solvents such as water and/or alcohols. For the purposes of this invention, average particle diameters of about 1 to 100 m.mu. are used, with particle diameters of about 5 to 30 m.mu. being particularly preferred. Various compounds can be used as the aluminum chelate compound which is component D, but preferred examples of compounds from the viewpoint of catalytic activity, solubility in the composition, and stability are aluminum acetylacetonate, aluminum ethyl acetoacetate, bisacetylacetate, etc. aluminum bisacetoacetate acetylacetonate, aluminum di-n-butoxide monoethylacetoacetate, aluminum di-i-propoxide monomethylacetoacetate, and mixtures of these compounds can also be used. The composition of the present invention may further contain the following component E, if necessary. . That is, it is at least one compound selected from the following group. (1) Hydrolyzate of methyltrialkoxysilane and/or γ-chloropropyltrialkoxysilane (2) Polyglycidyl ether of aliphatic polyol with an epoxy equivalent of 115 to 300 and an average of more than two epoxy groups per molecule Component E has an intermediary role so that component B, which improves adhesion, can be mixed with component A with good compatibility. Although it is preferable to increase the amount of component B under certain conditions, such as base material molding conditions or low curing temperature, the compatibility with other components may become poor.
The resulting paint film becomes cloudy, and the hardness of the paint film increases.
In particular, the abrasion resistance (measured by the pad abrasion test described in the Examples) decreases. By using the above component E, the compatibility is improved and the wear resistance properties are also improved. Examples of compounds that produce the hydrolyzate of component E (1) include methyltrimethoxysilane, methyltriethoxysilane, γ-chloropropyltrimethoxysilane, and γ-chloropropyltriethoxysilane. As the epoxy compound of component E(2), a reaction product of a polyhydric alcohol having at least three or more -OH groups in one molecule and epichlorohydrin is effective. Examples of these alcohols include glycerol, diglycerol, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol, and these may also be used in combination. The hydrolyzate of the compound mentioned in (1) of component A and component E above can be obtained by hydrolyzing the corresponding 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 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 together, but it is also possible to co-hydrolyze the mixed silanes, or to hydrolyze one silane and then It is also possible to apply a sequential hydrolysis method in which the other silane is added to the silane and the hydrolysis is continued. Next, before describing the mixing ratio of each of the above components, the calculated solid weight used as a reference will be defined below. The calculated solid weight W of the hydrolyzate (component A and component E(1)) is based on the weight of the silane compound QKSi(OS) _4-k (with molecular weight M ₀ ) used before hydrolysis.
If W ₀ , then the quantity defined by the following equation. W=W ₀ ·M ₁ /M ₀ where M ₁ is a formula quantity expressed as QKSiO _(4-k)/2 . In addition, Q and S are the component A explained earlier.
and a corresponding organic group in the silane compound used in component E(1), and k is 0, 1 or 2. The calculated solid weight of component B and component E (2) can be approximately the amount of each component used. The amount of component B used must be 10 to 80% of the sum of the calculated solid weights of component A and component B, respectively. If the amount is more than this, various physical properties and transparency will be deteriorated. If it is smaller than this range, the adhesion is insufficient. Component C is about 1 to 500 parts by weight based on 100 parts by weight of the total amount of Component A, Component B, and Component E added as necessary.
Parts by weight, preferably about 10 to 200 parts by weight, are used. If the amount of component C is low, the hardness will be low, and if it is high, coating defects such as cracking will occur. Furthermore, when this component is present in a large amount, the transmittance of the base material increases. The chelate compound of component D is the sum of component A, component B, component C, and component E when this is used.
About 0.01 to about 50 parts by weight, preferably about 0.1 to 20 parts by weight, are used. If the amount is less than this, curing will be insufficient, and if it is more than this, the transparency and adhesion between the coating material and the substrate will be reduced. 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 used, but it contains water of about 1% or more, preferably about 2% or more by weight. It is important to stabilize the coating composition. If the water content is less than 1%, the viscosity of the coating composition increases due to the reaction of the hydrolyzate of the silane compound, making it difficult to control the coating thickness. Furthermore, since a reaction occurs in the solution before coating, curing during the coating film formation stage is incomplete and the coating film hardness is not increased. The moisture in the coating composition may be generated due to insufficient hydrolysis of silanes, may be generated due to a condensation reaction of a hydrolyzate of silanes, or may be added separately from outside the system. Various additives other than those mentioned above can be used in 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. In addition, when used as a transparent base material, ultraviolet absorbers, antioxidants, etc. can be applied. Also, some of the coatings obtained from the compositions described in this invention can be dyed with dyes. Various organic polymers can also be used to improve paintability. Various types of polycarbonate molded articles are useful to be coated with the coating material of the present invention, but transparency, which is a characteristic of the coating material obtained from the coating composition of the present invention,
In order to take advantage of its scratch resistance and flexibility, plastic lenses such as sunglass lenses and corrective lenses, especially safety glasses lenses that take advantage of the impact resistance of polycarbonate, goggles, sun visors, watch covers, plastic case cases, etc.
Nameplates, various lighting fixtures, mirrors, safety glass, etc. are suitable. Various coating methods can be applied depending on the shape of the substrate used. For example, dip coating, spin coating, roll coating, curtain flow coating, etc. can be applied. Curing of the coating composition is accomplished by heating.
The heating temperature should be at a level that does not cause softening of the polycarbonate base material, and is preferably in the range of about 80 to 135°C. Depending on the base material, crazing may occur if the temperature reaches a high temperature in the initial stage, so a two-stage curing method in which initial curing is performed at a relatively low temperature and then post-curing is performed at a high temperature is also recommended. The characteristics of the composition of the present invention will be described below in Examples. It can be seen that in addition to good adhesion and hardness, transparency (total light transmittance) is improved. Example 1 (1) Preparation of γ-glycidoxypropylmethyldiethoxysilane hydrolyzate 386.3 g of γ-glycidoxypropylmethyldiethoxysilane was charged into a reactor equipped with a rotor, and the liquid temperature was adjusted to 10°C. While stirring with a magnetic stirrer, 55.8 g of 0.05N hydrochloric acid aqueous solution was gradually added dropwise. The time required for dropping was 83 minutes. After the dropwise addition was completed, cooling was stopped to obtain a hydrolyzate of γ-glycidoxypropylmethyldiethoxysilane (solid content hereinafter abbreviated as H-GMS).
61.3%. ). The properties of the obtained solution are epoxy equivalent
306, viscosity (10°C) 17.5 cps, and water content by gas chromatography was 5.1% by weight. (2) Preparation of paint 442.1 g of the above H-GMS, 97.3 g of Epicoat 827 (product of Ciel Chemical Co., Ltd., epoxy equivalent: approx. 185, bisphenol A type epoxy resin), 97.3 g of "Epicoat 834" (product of Ciel Chemical Co., Ltd., epoxy equivalent) Approximately 250, bisphenol A type epoxy resin)
58.9g, “Denacol EX320” (Nagase Sangyo Co., Ltd. product, epoxy equivalent approximately 130, trimethylolpropane polyglycidyl ether) 77.7g, diacetone alcohol 235.4g, benzyl alcohol 118.6g
Add 4.2 g of silicone surfactant, mix well, dissolve, and then add 1678.6 g of methanol-dispersed colloidal silica (product of Nissan Chemical Co., Ltd., "Methanol Silica Sol," solid content 30%) with stirring. 50.6 g of aluminum acetylacetonate was added to this mixed dispersion and mixed with stirring to obtain a paint. This paint has a solid weight of H-GMS of 271
g, and the solid content weight of the epoxy compound was 234 g, so the solid content weight ratio of (component B)/(component A+component B) as referred to in the present invention was 0.46. The average epoxy equivalent of component B was 20.5. (3) Application and evaluation Using the above-mentioned paint, apply it to a polycarbonate lens (diameter 60 mm, thickness 3.0 mm, "Lexan-141" manufactured by General Electric) using a dipping method at a pulling rate of 10 cm/min, and then apply hot air at 130°C. It was heated and cured in a dryer for 2 hours. The coated lenses were subjected to the following tests. The results are shown in Table 1. (a) Friction resistance test (a) Steel wool drag hardness Rub the coating surface with steel wool #0000,
We investigated the scratch resistance. The judgment was made as follows. A...It won't get scratched even if it is rubbed strongly. B...Slight scratches occur when rubbed very strongly.C...Scratch occurs even when rubbed weakly.Polycarbonate lenses that were not coated at all were worse than C. (b) Padded abrasion test Carbon random #600, 0.08g, diameter 30mm
wool felt (product of Nippon Felt Co., Ltd.)
Place the pad made of 20JRW (2mm thick) on the convex surface of the lens, and then
Rotate at a rate of 143 times/minute, and move the pad back and forth at a rate of 143 times/minute. After doing this for 14 minutes, the increase in haze on the lens surface was examined. (b) Appearance Transparency, presence of uneven coating, etc. were examined with the naked eye. (c) Adhesion After immersing the lens in hot water at 90℃ for 2 hours, make a goblin on the coating surface, firmly attach cellophane adhesive tape (trade name "Cellotape" manufactured by Nichiban Co., Ltd.), and turn it in a 90 degree direction. It was rapidly peeled off and the presence or absence of peeling of the paint film was examined. (d) Heat resistance test After immersing the lens in hot water at 90°C for 2 hours, the lens was cut into a lens frame and heated in a dryer at 100°C for 2 hours. Changes in the lens were examined. (e) Total light transmittance and haze value Measured according to the method of ASTM D1003-61. Comparative Example 1 (1) Preparation of paint 53.9 g of H-GMS of Example 1 was coated with “Epicoat”.
827” 11.74g, “Epicote 834” 7.14g, “Denacol EX320” 9.41g, diacetone alcohol 8.2g, benzyl alcohol 4.1g, silicone surfactant 0.32g and n-butanol
117.1g was added to dissolve the mixed liquid. Add 3.07g of aluminum acetylacetonate to this mixed solution.
was added and dissolved to make a paint. The solid weight ratio of (component B)/(component A + component B) of this paint is
0.46, and the average epoxy equivalent of component B is
It was 205. (2) Paint and Evaluation Using the paint described above, a performance test of the paint film was conducted in accordance with Example 1. The results are shown in Table 1. Example 2 (1) Preparation of silane hydrolyzate 212.4 g of γ-glycidoxypropyltrimethoxysilane was charged into a reactor equipped with a rotor, the liquid temperature was maintained at 10°C, and the mixture was stirred with a magnetic stirrer. , 0.01N hydrochloric acid aqueous solution 48.6g
Gradually drip. Immediately after the dropwise addition was completed, 38.4 g of γ-chloropropyltrimethoxysilane was added. Then continue with 0.01N hydrochloric acid aqueous solution 10.5
Gradually add g. After the dropwise addition was completed, cooling was stopped to obtain a silane hydrolyzate. (2) Preparation of paint 17.9g of “Epicoat 834” and “Epicron”
830” (Dainippon Ink & Chemicals Co., Ltd. product, epoxy equivalent approximately 180, bisphenol F type epoxy resin) 124.8g, silicone surfactant
293.2 g of the silane hydrolyzate is added to a solution of 2.77 g dissolved in 186.8 g of benzyl alcohol and 112.1 g of diacetone alcohol and mixed. Add methanol silica sol to this mixed solution.
1027.8 g, methanol 54.9 g, and aluminum acetylacetonate 30.9 g were added in this order, and the mixture was stirred and mixed to obtain a paint. The solid content weight ratio of (component B)/(component A+component B) of this paint was 0.44, and the average epoxy equivalent of component B was 187. (3) Application and evaluation Using the paint described above, application and evaluation were performed according to Example 1. The results are shown in Table 1. Example 3 (1) Preparation of paint 186.8 g of H-GMS from Example 1 was coated with “Epicoat”.
827” 40.9g “Epicote 834” 24.7g, diacetone alcohol 85.4g, benzyl alcohol
42.7 g and 1.5 g of silicone surfactant were added and mixed by stirring. After adding and mixing 600g of methanol silica sol to this mixed solution,
18 g of aluminum acetylacetonate was added and mixed to prepare a paint. (Component B) of this paint/
The solid weight ratio of (component A+component B) was 0.36, and the average epoxy equivalent of component B was 205. (2) Application and evaluation Using the paint described above, application and evaluation were performed according to Example 1. The results are shown in Table 1. Comparative Example 2 Uncoated polycarbonate lens in Example 1
The evaluation was conducted according to the following. The results are shown in Table 1. Example 4 (1) Preparation of paint Add 58.9 g of methyltrimethoxysilane to 284 g of H-GMS from Example 1 and prepare a 0.01N aqueous hydrochloric acid solution.
Add 23.4g dropwise while stirring with a magnetic stirrer while maintaining the liquid temperature at 10℃. The reaction completes in about 60 minutes. Add to this 72.5g of “Epicote 827”, 43.5g of “Epicote 834”, and diacetone alcohol.
154.5 g, benzyl alcohol 77.3 g, and silicone surfactant 2.7 g were added and mixed with stirring. Add methanol silica sol to this mixed solution.
After adding and mixing 1063 g, 31.9 g of aluminum acetylacetonate was added and mixed to obtain a paint. (Component B)/(Component A+) of this paint
The solids weight ratio of component B) is 0.33;
The average epoxy equivalent weight of the components was 205. (2) Application and evaluation The coating described above was applied and evaluated in accordance with Example 1. The results are shown in Table 1. Comparative Example 3 To 50.0 g of H-GMS of Example 1, 102 g of methanol silica sol, 15.2 g of diacetone alcohol, 7.6 g of benzyl alcohol, and 36.5 g of n-butanol were added.
g and 0.32 g of silicone surfactant were added and mixed with stirring. 3.07 g of aluminum acetylacetonate was added to this liquid mixture, and the mixture was stirred to form a paint. Apply this paint according to Example 1,
evaluated. The results are shown in Table 1.

[Table] Examples 5 to 7, Comparative Examples 4 to 5 In Example 1, “Epicote 1001” (product of Ciel Chemical Co., Ltd., epoxy equivalent: about 475, bisphenol A type epoxy resin) was used instead of “Epicote 834”. The experiment was conducted in the same manner as in Example 1 except that "Epicote 827" and "Epicote 1001" were added in the amounts shown in Table 2.The results are shown in Table 2.

【table】

Claims (1)

[Claims] 1 Contains the following components A, B, C, and D, and the mixing ratio of components A and B is solid content weight ratio, (component B)/(component A + component B) = 0.1 to A coating composition for polycarbonate molded articles, characterized in that the weight ratio is 0.8. A Hydrolyzate of γ-glycidoxypropylmethyldialkoxysilane and/or hydrolyzate of γ-glycidoxypropyltrialkoxysilane. B: An epoxy compound having an epoxy equivalent of 400 or less and having the following structural formula. (Here, R ₁ , R ₂ and R ₃ are H or CH ₃ ,
n is an integer greater than or equal to 0. ) C Particulate silica having an average particle diameter of about 1 to about 100 mμ. D General formula A. _Xo . An aluminum chelate compound represented by Y _3-o (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. ).