JP2800236B2 - Cured film - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a coating composition for plastic moldings, and in particular to a coating composition for protecting plastic moldings.

[Conventional technology]

Plastic molded products are used in large quantities, taking advantage of their advantages such as light weight, easy processability, and impact resistance, but on the other hand, they have insufficient hardness, are easily damaged, are easily eroded by solvents, and are charged with dust. It has drawbacks such as adsorption of heat and insufficient heat resistance, and has been practically unsatisfactory compared to inorganic glass molded articles when used as eyeglass lenses or window materials.

Therefore, it has been proposed to apply a protective coat to a plastic molded product. Numerous types of coating compositions for use in coatings have been proposed. Among them, there is a “coating composition containing an organosilicon compound or a hydrolyzate thereof as a main component (resin component or coating film forming component)” which is expected to give a hard coating film close to an inorganic type (for example, This is practically used for eyeglass lenses.

However, this coating composition is still unsatisfactory in abrasion resistance (scratch resistance). Therefore, a composition in which silica sol dispersed in a colloidal form is added thereto has been proposed (see, for example, JP-A-53-111336). This is also put to practical use for eyeglass lenses.

By the way, conventionally, almost 100% of plastic glasses lenses have been manufactured by casting polymerization of a monomer called diethylene glycol biscarbonate (commonly called CR-39). This lens has a refractive index of about 1.50, which is lower than the refractive index of a glass lens of about 1.52.
In the case of a myopic lens, there is a drawback that the thickness of the rim becomes thick, and this has been a main cause of being disliked by the wearer.

For this reason, the development of monomers higher than CR-39 has been promoted, and for example, JP-A-55-13747 and JP-A-56-166214.
And JP-A-57-23611 and JP-A-57-54901. At present, several companies have commercialized plastic lenses having a medium to high refractive index of n _d = 1.54 to 1.60.

These lenses are also coated with the coating composition containing the silica sol.

[Problems to be solved by the invention]

However, the coating composition to which silica sol is added has a first problem that interference fringes can be seen in the coating film and the appearance of the lens is poor.

In addition, in many lenses, an antireflection film (consisting of a multilayer structure film of an inorganic oxide thin film based on the theory of optical interference) is formed on a coating film. In this case, the antireflection film exhibits, for example, an extremely light green reflection color, but this reflection color changes according to the position of the lens surface, and there is a second problem that there is unevenness.

Therefore, a first object of the present invention is to provide a coating film in which interference fringes are not visible and the reflection color is not uneven for a medium to high refractive index plastic molded product with n _d = 1.54 to 1.60. It is to provide a coating composition.

The second object of the present invention is to provide abrasion resistance, surface hardness,
An object of the present invention is to provide a coating composition for a plastic molded article having excellent abrasion resistance, flexibility, transparency, antistatic property, dyeability, heat resistance and the like.

[Means for solving the problem]

Therefore, the present invention provides: (a) a general formula: R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)} (formula I) (wherein, R ¹ has an epoxy group an organic group or an organic group having 4 to 14 carbon atoms and having an unsaturated double bond, R ² is a hydrocarbon group or a halogenated hydrocarbon group having 1 to 6 carbon atoms, R ³ is C 1 -C A to b are each 0 or 1, and a + b
Is 1 or 2. A cured film obtained by curing a coating composition comprising an organosilicon compound represented by the formula or a hydrolyzate thereof; and (b) a tungsten oxide sol dispersed in a colloidal form.

[Action]

Description of the component (a): Among the compounds of the general formula (I), when R ¹ has an epoxy group as a functional group, for example, the following compounds are used.

(1) General formula (II): (Wherein, in the formula, R ⁴ is an alkyl group or alkoxyalkyl group or an acyl group having 1 to 4 carbon atoms, and R ⁵ is a 1 to 6 carbon atoms.
R ⁶ is a hydrogen or methyl group, m is 2 or 3, p is 1 to 6, and q is 0 to 2.
It is. ) The compound represented by these.

(1) General formula (III): (However, R ⁷ is an alkyl group or an alkoxyalkyl group or an acyl group having 1 to 4 carbon atoms, R ⁵ is a hydrocarbon group or a halogenated hydrocarbon group having 1 to 4 carbon atoms, 1 is 2 or 3, r Is 1-4.) A compound represented by the formula:

Each of the compounds represented by the above general formula has an epoxy group, and is therefore called epoxysilane.

Specific examples of epoxysilane include, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxyethoxysilane, γ-glycidoxypropyltriacetoxysilane , Γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane and the like.

Further, among the compounds of the general formula (I), those other than those in which R ¹ has an epoxy group as a functional group (including those in which a = 0)
For example, the following is used.

Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-methacryloxypropyltrimethoxysilane, aminomethyltrimethoxysilane, 3-
Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, phenyltrimethoxysilane,
Various trialkoxysilanes such as phenyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, trisiloxysilane or trialkoxyalkoxysilane compounds .

All of the exemplified compounds of the general formula (I) described above are
This is an example of a trifunctional compound having three OR ³ groups (a + b = 1) bonded to a Si atom, but a bifunctional compound having two OR ³ groups (a + b = 2) can of course also be used. .
Examples of bifunctional equivalent compounds include dimethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, methylvinyldimethoxysilane, dimethyldiethoxysilane, and the like.

The compound of the general formula (I) may be used alone,
Two or more kinds may be mixed and used according to the purpose.

In particular, when a bifunctional compound is used, it is preferable to use a trifunctional compound in combination. When used together,
On average, 2> a + b> 1.

Furthermore, it is also possible to use a tetrafunctional equivalent compound of a + b = 0 in combination. Examples of tetrafunctional corresponding compounds include methyl silicate, ethyl silicate, isopropyl silicate, n-propyl silicate, n-butyl silicate, t-butyl silicate, sec-butyl silicate and the like.

The compound of the general formula (I) may be used as it is, but is preferably used as a hydrolyzate for the purpose of increasing the reaction rate and lowering the curing temperature. When two or more compounds having the same functionality are used in combination of two to four functional compounds,
Alternatively, when two or more compounds having different functional numbers are used in combination,
They may be used together after hydrolysis or may be used together before hydrolysis to carry out co-hydrolysis. Upon hydrolysis, the alcohol HOR ³ is released, and the compound of general formula (I) corresponds to become. Silanol rapidly undergoes dehydration condensation to become an oligomer. Therefore, for this reaction to proceed sufficiently,
After hydrolysis, it may be left (cured) for 1 to 24 hours.

Description of Component (b): The tungsten oxide of the tungsten oxide sol dispersed in a colloidal state can be represented by W ₂ O ₅ to WO ₃ .

Such a sol itself is known and partially available as a commercial product. The particle size of the sol is from 1 to 200 mμ, especially from 5 to
100 mμ is preferred. If it is smaller than this, the production is difficult, the stability of the sol itself is poor, and the effect is small.If it is larger than this, the stability of the coating composition,
Transparency, smoothness, etc. of the coating film decrease.

The sol is a colloidal solution in which tungsten oxide fine particles are dispersed in water, an organic solvent, or a mixed solvent of both, and a sol which is stabilized by adding an appropriate alkali, particularly an organic amine, is useful.

Description of Component (c): The curing catalyst (c) is used as necessary to shorten the time required for polymerizing the component (a) to form a three-dimensional network coating film ( However, those that impair the stability of the coating composition are not preferred),
For example, the following is used.

(1) Amines: monoethanolamine, diethanolamine, isopropanolamine, ethylenediamine, isopropylamine, diisopropylamine, morpholine, triethanolamine, diaminopropane, aminoethylethanolamine, dicyandiamine, triethylenediamine,
-Ethyl-4-methylimidazole.

(2) Various metallic complex compounds: formula: AlX _n Y _3-n (In the formula, X is 0L (L is a lower alkyl group), Y is the formula ^{_{M 1 COCH 2 COM 2 (M}} 1, M 2 Is a lower alkyl group) and M ¹ COC
At least one selected from ligands derived from H ₂ COOM ² and n is 0, 1 or 3).

Particularly useful chelate compounds include aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum-di-n-butoxide-monoethylacetoacetate, and aluminum-acetylacetonate from the viewpoint of solubility, stability, and catalytic effect. Di-iso-propoxide monomethyl acetoacetate.

In addition, chromium acetylacetonate, titanyl acetylacetonate, cobalt acetylacetonate, iron (III) acetylacetonate, manganese acetylacetonate, nickel acetylacetonate.

(3) Metal alkoxide: aluminum triethoxide, aluminum tri-n-propoxide, aluminum tri-n-butoxide, tetraethoxytitanium, tetra-n-butoxytitanium, tetra-i-
Propoxy titanium.

(4) Organic metal salts: sodium acetate, zinc naphthenate, cobalt naphthenate, zinc octylate, tin octylate.

(5) Perchlorates: magnesium perchlorate and ammonium perchlorate.

(6) Organic acids or anhydrides: malonic acid, succinic acid, tartaric acid, adipic acid, azelaic acid, maleic acid, O-phthalic acid, terephthalic acid, fumaric acid, itaconic acid, oxaloacetic acid, succinic anhydride, maleic anhydride Acid, itaconic anhydride, 1,2-dimethylmaleic anhydride, phthalic anhydride, hexahydrophthalic anhydride,
Naphthalic anhydride.

(7) Lewis acid: ferric chloride, aluminum chloride.

(8) Metal halides: stannous chloride, stannic chloride, tin bromide, zinc chloride, zinc bromide, titanium tetrachloride, titanium bromide, thallium bromide, germanium chloride, hafnium chloride, lead chloride, odor Lead.

The above catalysts may be used alone or in combination of two or more. In particular, when the component (a) has an epoxy group, one that also functions as a ring-opening polymerization catalyst for the epoxy group may be used.

In particular, an aluminum chelate compound is one of the preferred catalysts.

Description of Component (d): The solvent (d) is used as necessary to make the coating composition liquid or to lower the viscosity.
For example, water, lower alcohol, acetone, ether, ketone, ester and the like are used. In the coating composition of the present invention, the component (b) is used in an amount of 10 to 400 parts by weight (solid content), preferably 50 to 100 parts by weight (solid content) of the component (a).
It is appropriate to use the component (c) in an amount of 0.00001 to 20 parts by weight based on 100 parts by weight (solid content) of the components (a) and (b) in total.

The component (d) is used in an appropriate amount depending on the viscosity of the composition.

In addition to the above components (a) to (d), if necessary, for example, improvement in adhesion to a substrate (molded product) on the side to be coated,
Various additives may be used in combination for the purpose of improving the weather resistance or for improving the stability of the coating composition.

Examples of additives include pH adjusters, viscosity improvers, leveling agents, matting agents, dyes, pigments, stabilizers, UV absorbers, antioxidants, and the like.

In addition, an epoxy resin or another organic polymer may be used in combination for the purpose of improving the dyeability of the coating film. Epoxy resins are widely used for paints and castings. Polyolefin epoxy, cyclopentadiene oxide, cyclohexene oxide or alicyclic epoxy resin such as polyglycidyl ester, polyglycidyl ether, epoxidized vegetable oil, novolak type phenol resin and epichlorohydrin, epoxy novolak, and even glycidyl methacrylate Examples include methacrylate copolymers.

Other organic polymers include, for example, polyols, cellulose resins, melamine resins, and the like.

Various surfactants can be used in combination with the coating composition for the purpose of improving the flow at the time of application, improving the smoothness of the coating film and reducing the friction coefficient of the coating film surface, and in particular, dimethyl siloxane A block or graft copolymer of styrene and an alkylene oxide, and a fluorine-based surfactant are effective.

In some cases, inorganic fillers such as silica sol, antimony oxide sol, and diamond fine particles may be used in combination as long as the object of the present invention is not impaired.

The compositions according to the invention are applied in particular to plastic moldings. Speaking of the molded product from the material, for example, polymethyl methacrylate and its copolymer, acrylonitrile styrene copolymer, polycarbonate, cellulose acetate, polyvinyl chloride, polyethylene terephthalate,
The composition of the present invention is applied to an epoxy resin, an unsaturated polyester resin, a polyurethane resin, a polymer of CR-39, and the like.

In terms of the form of the molded product, the composition of the present invention is applied to a lump, a wire, a film, and the like.

In terms of the function of the molded product, the composition of the present invention is applied to optical products, particularly camera lenses, eyeglass lenses, reflectors, prisms and the like.

The composition of the present invention is particularly useful as an anti-scratch film for “glass lenses” molded from a resin having a medium to high refractive index of n _d = 1.53 or more.

In addition, the composition of the present invention is not limited to plastic molded articles, and can be applied to inorganic glass, wood, metal articles, and the like.

As a coating means, a normal coating method such as brush coating, dipping, roll coating, spray coating, and flow coating can be used.

Furthermore, after applying the composition of the present invention to a mold, the raw material to be a substrate molded product is cast and polymerized to form a plastic molded product, or after the composition of the present invention is applied to the molded product, it is still cured. An uncoated film surface can be brought into close contact with a mold, and the coating film can be cured thereon.

After being applied, the coating composition of the present invention is often cured by heat treatment to obtain a hard coating film. A sufficient effect can be obtained at a heating temperature of about 50 to 200 ° C, preferably 80 to 140 ° C.

The thickness of the coating is generally 0.3-30 μm after drying, preferably
0.5 to 10μ is sufficient.

The coating film is transparent and excellent in hardness, especially scratch resistance, and does not cause deterioration in appearance due to scratches, which is a problem of plastic molded products, and can provide molded products with extremely high commercial value.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

〔Example〕

(1) Preparation of Preliminary Composition A: 248 parts by weight of γ-glycidoxypropylmethyldiethoxysilane was charged into a reaction vessel equipped with a rotor, and while stirring vigorously using a magnetic stirrer, a 0.05 N hydrochloric acid aqueous solution was added. 36 parts by weight were added all at once.

Immediately after the addition, the solution was a heterogeneous solution, but became a uniform, colorless and transparent solution while generating heat within a few minutes. Stirring was further continued for 1 hour to obtain a hydrolyzate corresponding to the component (a).

Ethanol was added to the obtained hydrolyzate as component (d).
After 56.6 parts by weight of ethylene glycol and 53.4 parts by weight of ethylene glycol were added, 4.7 parts by weight of aluminum acetylacetonate was added as the component (c), and the mixture was sufficiently mixed and dissolved to prepare a preliminary composition A.

(2) Preparation of Preliminary Composition B: 212.4 parts by weight of γ-glycidoxypropyltrimethoxysilane was charged into a reaction vessel equipped with a rotor, the temperature in the vessel was kept at 10 ° C., and a magnetic stirrer was used. With vigorous stirring, 48.6 parts by weight of a 0.01 N hydrochloric acid aqueous solution was gradually added dropwise. Immediately after the completion of the dropping, the cooling was stopped to obtain a uniform, colorless and transparent solution-like hydrolyzate corresponding to the component (a).

Ethanol was added to the obtained hydrolyzate as component (d).
After 77.1 parts by weight of ethylene glycol and 37.7 parts by weight of ethylene glycol were added, 7.65 parts by weight of aluminum acetylacetonate was added as the component (c), and the mixture was sufficiently mixed and dissolved to prepare a preliminary composition B.

(3) Preparation of coating composition: The preparative compositions A and B prepared in the above (1) and (2) were weighed and poured into a glass container by weight (not solid content) shown in Table 1 below. Put into it a commercially available tungsten oxide sol (water-dispersed sol, average particle diameter: 10-15 mμ, solid content 20
%) (0.45 parts by weight) and a silicone-based surfactant were added thereto and sufficiently stirred and mixed to prepare a uniform, colorless and transparent solution-like coating composition.

(4) Coating: A commercially available polycarbonate lens having a refractive index n _d = 1.59 was prepared, and the above coating composition was applied thereto by a dipping method (pulling speed: 10 cm / min), followed by heat treatment at 100 ° C. for 2 hours. To cure the coating.

(5) Evaluation: The lens with the cured coating film obtained in (4) above was subjected to the following test to evaluate the performance of the coating film.

(A) Friction resistance test The surface of the coating film was rubbed with steel wool # 0000, and the scratch resistance was examined. In addition, evaluation was performed as follows.

 ◎: No scratches even with strong friction.

 …: Slightly scratched when rubbed quite strongly.

 ×: Scratches even with weak friction.

 Incidentally, the evaluation of the lens without the coating film was x.

(B) Appearance A general-purpose anti-reflection film was formed on the coating film cured in the above item (4) by a vacuum deposition method, and the unevenness of the reflection color was visually observed, and evaluated as follows.

◎: No uneven reflection color ○: Some uneven reflection color ×: Extremely uneven reflection color (c) Adhesion After immersing the lens having the cured coating film in hot water at 90 ° C for 2 hours, 100 goban eyes were made by making cut lines in the vertical and horizontal directions every 1 mm on the membrane surface with a knife, and then a cellophane adhesive tape (trade name "Cellotape" manufactured by Nichiban Co., Ltd.) was strongly adhered. With one end of the tape in hand, the tape was rapidly peeled off in the direction of 90 degrees, and the number of peeled goban eyes on the coating film was examined. The number X of the eyes of the peeled goban is expressed as X / 100 with the numerator as the numerator. The smaller the X, the better the adhesion.

(D) Dyeability The lens having the cured coating film was immersed in a disperse dye (mixed three colors of red, yellow, and blue) bath at 90 ° C. for 30 minutes, and the degree of dyeing was measured by light transmittance.

 The results of the above evaluations are shown in Table 1 below.

[Comparative Example 1] In the examples, a commercial silica sol (methanol dispersion sol, average particle diameter: 13) was used instead of the tungsten oxide sol.
A coating composition of this example was prepared and evaluated in substantially the same manner as in the example, except that ± 1 μm, solid content 20%) was used.

[Comparative Example 2] In the examples, a commercially available antimony pentoxide sol (average particle diameter: 15 mμ, solid content
20%) was used, and the coating composition of this example was prepared and evaluated in substantially the same manner as in the example.

 The results of the above evaluations are shown in Table 1 below.

[Effects of the Invention] As described above, according to the present invention, a coating composition having the following characteristics can be obtained.

(1) When a hard coating film is formed by applying to a medium to high refractive index plastic spectacle lens and an antireflection film is formed thereon, there is no unevenness of the reflection color.

(2) Scratch resistance, surface hardness, abrasion resistance, flexibility,
Excellent transparency and heat resistance.

(3) The elongation of the coating film is large, and the risk of crack generation on the coating film surface is extremely small even when the substrate is bent.

(4) There is no trouble such as curling when the film is applied to a thin film with a small shrinkage upon curing.

(5) The coating film has an excellent antistatic property and is relatively hard to stain.

(6) The coating film can be dyed with a disperse dye.

(7) The surface reflectance of the coating film is large.

(8) Adhesion of an antireflection film, a metal deposition film and the like to the coating film is good.

(9) Good sliding properties on the coating film surface (low friction coefficient).

Claims (1)

(57) [Claims] 1. A cured film obtained by curing a coating composition mainly comprising: (A) General formula: R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)} (formula I) (wherein, R ¹ is an organic group having an epoxy group or an unsaturated group) an organic group of 4-14 carbon atoms having a double bond, R ²
Is a hydrocarbon group having 1 to 6 carbon atoms or a halogenated hydrocarbon group, R ³ is an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group or an acyl group, and a and b are each 0 or 1, and a + b is 1 or 2. And (b) a colloidally dispersed tungsten oxide sol.