JP3079539B2 - Coating composition and plastic molded article to which it is applied - 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 in comparison with 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.

Conventionally, most plastic glasses lenses have been manufactured by cast polymerization of a monomer called diethylene glycol bisallyl carbonate.
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. Had become.

Therefore, the development of monomers higher than diethylene glycol bisallyl carbonate has been promoted, and for example, JP-A-55-13747, JP-A-56-166214, and JP-A-57-23611.
And JP-A-57-54901 have been proposed. Currently,
Several companies have commercialized plastic lenses with 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 properties, dyeing properties, heat resistance, water resistance, chemical resistance, and the like.

[Means for solving the problem]

Therefore, the present invention relates to: (a) a general formula: R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)} (formula I) (wherein, R ¹ is a functional group or an unsaturated group) 4 to 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, a and b are each 0 or 1, and a + b is
1 or 2. (B) a composite sol of tin oxide and tungsten oxide dispersed in colloidal form; and, optionally, (c) a curing catalyst; and, optionally, (d) a solvent; A coating composition characterized by comprising:

[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, q is 0 to
2. ) The compound represented by these.

(2) 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 ⁸ is a hydrocarbon group or a halogenated hydrocarbon group having 1 to 4 carbon atoms, 1 is 2 or 3, r
Is 1-4. ) The compound represented by these.

Since all of the compounds represented by the above general formula have a oxy group, they are also called epoxysilanes.

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 it in combination with a trifunctional compound. 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 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 functionalities are used in combination, they may be used together after hydrolysis, or may be used in combination before hydrolysis to carry out co-hydrolysis. HOR ³ by hydrolysis
Is released, and the compound of the general formula (I) is
Equivalent silanol: 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.

(B) Description of Components: A composite sol of tin oxide and tungsten oxide dispersed in a colloidal form is used.

The ratio of tin oxide to tungsten oxide is 100 tin oxide
It is 2 to 100 parts by weight of tungsten oxide with respect to parts by weight.

Tin oxide sols, tungsten oxide sols, and composite sols of tin oxide and tungsten oxide dispersed in a colloidal form are each known, and some of them are available as commercial products.

Tin oxide sol is preferable because it has a high refractive index and exists alone as a sol. However, the intrinsic property of the substance cannot be stably present with the component (a). Tungsten oxide sol has a relatively high refractive index, exists alone as a sol, and can exist stably with component (a). However, the coating composition formed of component (a) and tungsten oxide sol There is a problem with water resistance.

By using a composite sol of tin oxide and tungsten oxide, the disadvantages of both can be compensated and preferable properties can be obtained. That is, it is possible to obtain a coating composition having a high refractive index, which is stable with the component (a) and has no problem in durability.

The ratio of tin oxide to tungsten oxide is 2 to 100 parts by weight, preferably 5 to 50 parts by weight with respect to 100 parts by weight of tin oxide, in order to make use of the advantages of each and compensate for the disadvantage. If the ratio is lower than this, the stability when mixed with the component (a) is lacking, and if the ratio is higher than this,
There is a problem with the water resistance of the coating composition.

The particle size of the sol is preferably 1 to 200 mμ, particularly preferably 5 to 100 mμ. 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, the transparency and the smoothness of the coating film, etc. will be reduced.

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

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, dicyandiamide, triethylenediamine,
2-ethyl-4-methylimidazole.

(2). Various metal complex compounds: General formula: AlX _n Y _3-n (where X is OL (L is lower alkyl group), Y is general formula M ¹ COCH ₂ COM ² (M ¹ and M ² are 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 2).

Particularly useful chelate compounds include aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum-di-n-butoxide-monoethylacetoacetate, and aluminum-acetate from the viewpoint of solubility, stability, and catalyst curing. And di-iso-propoxide-monomethylacetoacetate.

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

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

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

(5). Perchlorates: magnesium perchlorate, ammonium perchlorate.

(6). Organic acid or anhydride thereof: 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, anhydride Itaconic acid, 1,2-dimethylmaleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, naphthalic anhydride.

(7). Lewis acids: 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, lead bromide.

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 2 parts per 100 parts by weight (solid content) of the component (a).
It is appropriate to use 50 parts by weight (solid content) and 0.00001 to 20 parts by weight of the component (c) per 100 parts by weight (solid content) of the total of the components (a) and (b).

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 adjusters, 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 include paints, polyolefin epoxy, cyclopentadiene oxide, cyclohexene oxide, or cycloaliphatic epoxy resins such as polyglycidyl esters, polyglycidyl ethers, epoxidized vegetable oils, and novolaks, which are widely used for casting. There are epoxynophoracs composed of a type phenol resin and epichlorohydrin, as well as glycidyl methacrylate and methyl methacrylate copolymer.

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 molded materials, 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 resin molded “glass lenses” 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 the composition of the present invention is applied to a mold, a plastic molded product is formed by casting the raw material as a substrate molded product 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 the 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 were charged into a reaction vessel equipped with a rotor, and while stirring vigorously using a magnetic stirrer, 36 parts by weight of a 0.05 N hydrochloric acid aqueous solution. Was 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 adding 56.6 parts by weight of ethylene glycol and 53.4 parts by weight of ethylene glycol, 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: A reactor equipped with a rotor was charged with 212.4 parts by weight of γ-glycidoxypropyltrimethoxysilane, the temperature in the vessel was kept at 10 ° C., and the mixture was vigorously stirred using a magnetic stirrer. Meanwhile, 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: Preparatory compositions A and B prepared in the above (1) and (2) were weighed and poured into a glass container by weight (not solid content) as shown in Table 1 below. Commercially available composite sol of tin oxide and tungsten oxide (water-dispersed sol, average particle size: 10
~ 15mμ, ratio of tin oxide to tungsten oxide: 100 parts by weight / 40 parts by weight, solid content 20%) 200 parts by weight (not solid content), and silicone surfactant 0.45 parts by weight, and sufficiently stirred By mixing, a uniform, colorless and transparent solution-like coating composition was prepared.

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

(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 irregularities in reflected color ○ …… あ り Slightly present × …… 著 し い Marked (c) Adhesion After immersing the lens with the cured coating film in hot water at 90 ° C for 2 hours, apply a 1mm knife to the coating film surface. Cut lines were made in the vertical and horizontal directions every other to make 100 goban eyes, and then cellophane adhesive tape (trade name) "Cellotape" manufactured by Nichiban Co., Ltd. was strongly attached. 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 example, a commercial silica sol (methanol-dispersed sol, average particle diameter: 13 ± 1 mμ, solid content 20%) was used in place of the composite sol of tin oxide and tungsten oxide. The coating composition of this example was prepared and evaluated in substantially the same manner as in Example 1.

[Comparative Example 2] Almost the same as the Example, except that a commercially available antimony pentoxide sol (average particle diameter: 15 mμ, solid content: 20%) was used in place of the composite sol of tin oxide and tungsten oxide in the example. The coating composition of this example was prepared and evaluated.

 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 anti-reflection film is formed thereon, there is no unevenness of the reflection color.

(2). Excellent scratch resistance, surface hardness, abrasion resistance, flexibility, transparency, heat resistance, water resistance, etc. of the coating film.

(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). The shrinkage during curing is small, and there is no problem such as curling when applied to a thin film.

(5). The coating has excellent antistatic properties and is relatively resistant to staining.

(6). The coating can be dyed with disperse dyes.

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

(8). Good adhesion of anti-reflection film, metal deposition film, etc. to the coating film.

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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 1/00-201/10 C08K 1/00-13/08 C08L 1/00-101/16 C01G 25 / 00-57/00 CA (STN) REGISTRY (STN) WPI (DIALOG)

Claims (4)

(57) [Claims] (A) a general formula: R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)} (1) (where R ¹ is Having 4 to 14 carbon atoms having a functional group or an unsaturated 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, a and b are each 0 or 1, and a + b is
(B) a composite sol of tin oxide and tungsten oxide dispersed in a colloidal form; and 100 parts by weight of the tin oxide is tungsten oxide. A coating composition comprising 2 to 100 parts by weight. 2. A plastic film having a refractive index of 1.54 to 1.60, having a transparent coating film, which comprises: (a) a general formula: R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)} (Formula 1) (wherein, R ¹ is a C 4-14 carbon atom having a functional group or an unsaturated 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, a and b are each 0 or 1, and a + b is
Or a hydrolyzate thereof; (b) a composite sol of tin oxide and tungsten oxide dispersed in a colloidal form; and a coating composition comprising: Plastic moldings. 3. The plastic molded product according to claim 2, wherein the transparent coating has a thickness of 0.3 to 30 μm. 4. The plastic molding according to claim 2, wherein the transparent coating has a three-dimensional network structure.