JPH044273A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition giving a film not generating interference band nor reflection unevenness on a coated film comprising a specific organic silicon compound or hydrolysate of the compound, colloidally dispersed tin oxide and tungsten oxide, a curing catalyst and a solvent. CONSTITUTION:(A) An organic silicon compound such as methyl trimethoxysilane expressed by the formula or hydrolysate of the compound [R1 is functional group or 4-14C organic group having unsaturated double bond; R2 is 1-6C (halogenated) hydrocarbon; R3 is 1-4C (alkoxy)alkyl or acyl; a and b are 0 or 1; a+b=1 or 2] is mixed with (B) compound sol of colloidally dispersed tin oxide and tungsten oxide, and occasionally (C) a curing agent such as monoethanolamine, and (D) a solvent such as water or ether, as necessary, to afford the aimed coating composition having excellent resistance to scratch, surface hardness, wear resistance and transparency, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a coating composition for plastic moldings, in particular to a coating composition for protecting plastic moldings.

[Conventional technology]

Plastic molded products are used in large quantities due to their advantages such as light weight, easy processability, and impact resistance. However, on the other hand, they do not have sufficient hardness and are easily scratched, are easily attacked by solvents, and are electrostatically charged and dusty. It has drawbacks such as adsorption of water and insufficient heat resistance, and is unsatisfactory in practical terms compared to inorganic glass molded products when used as eyeglass lenses, window materials, etc.

Therefore, it has been proposed to apply a protective coat to plastic molded products. Many types of coating compositions have been proposed for use in coating.

Among them, there are coating compositions whose main component (resin component or film-forming component) is an organosilicon compound or its hydrolyzate, which is expected to provide a hard coating film close to that of an inorganic system (for example, , JP-A-52-11261), which has been put into practical use as an eyeglass lens.

However, this coating composition is still unsatisfactory in its scratch resistance (resistance to scratches), so it has been proposed to add colloidally dispersed silica sol to it (for example, see JP-A-53-111336). This has also been put into practical use for eyeglass lenses.

By the way, conventionally, most plastic eyeglass lenses have been manufactured by casting polymerization of a monomer called diethylene glycol bisallyl carbonate. This lens has a refractive index of approximately 1°50, which is lower than the refractive index of glass lenses, which is approximately 1.52, so it has the disadvantage that the edge of the lens is thicker when used as a nearsighted lens. This was the main reason for his dislike.

Therefore, the development of monomers higher than that of diethylene glycol bisallyl carbonate has progressed, and for example, JP-A-55-13747, JP-A-56166-214, JP-A-57-23611, and JP-A-57-54901 have been proposed. Ta. Currently, na=1.54~1 from several companies.
．． 60 medium to high refractive index plastic lenses are now commercially available.

These lenses are also coated with the aforementioned coating composition to which silica sol is added.

[Problem that the invention seeks to solve]

However, the first problem with the coating composition to which silica sol is added is that interference fringes are visible on the coating film and the appearance of the lens is poor.

Also, in the lens, V! An antireflection M (consisting of a multilayer structure film of inorganic oxide thin films based on optical interference theory) is often formed on the film. In this case, the antireflection film exhibits a reflective color of, for example, pale green. The second problem was that the reflected color changed depending on the position on the lens surface and was uneven.

Therefore, the first object of the present invention is that n<=1.54 to 1.
To provide a coating composition that provides a coating film on a medium to high refractive index plastic molded article of No. 60 in which no interference fringes are visible and the reflective color is uniform.

A second object of the present invention is to provide excellent scratch resistance, surface hardness, abrasion resistance, flexibility, transparency, antistatic properties, dyeability, heat resistance, water resistance, chemical resistance, etc. An object of the present invention is to provide a coating composition for plastic molded articles.

[Means for Solving the Problems] Therefore, the present invention provides the following: (a) General formula: R', R"b S 1COR") a-n-b) River (Formula ■
) (wherein, R1 has 4 to 4 carbon atoms and has a functional group or an unsaturated double bond)
14 organic group, Rz is a hydrocarbon group or halogenated hydrocarbon group having 1 to 6 carbon atoms, R3 is an alkyl group, alkoxyalkyl group, or acyl group having 1 to 4 carbon atoms, and a and b are each 0 or l, and a+b is
! Or 2. ) an organosilicon compound or its hydrolyzate; (b) a composite sol of colloidally dispersed tin oxide and tungsten oxide; and optionally (c) a curing catalyst; and optionally (d) a solvent; A coating composition is provided.

[Effect]

Regarding the compounds of formula (1) in which R1 has an epoxy group as a functional group, for example, the following are used.

(1) General formula (■): (However, in the formula, R4 is an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group or an acyl group, and R5 is a carbon number 1
-6 hydrocarbon group or halogenated hydrocarbon group, R- is hydrogen or methyl group, m is 2 or 3, p is 1-6, q
is 0-2. ).

(2) General formula (■): (However, R? is an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group, or an acyl group, and R- is a hydrocarbon group having 1 to 4 carbon atoms or a halogenated carbon group. Hydrogen group, l is 2 or 3
, r is 1-4. ).

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

Specific examples of epoxysilane include T-glycidoxypropyltrimethoxysilane, T-glycidoxypropyltriethoxysilane, T-glycidoxypropyltrimethoxyethoxysilane, and T-glycidoxypropyltrimethoxysilane. Examples include triacetoxysilane, T-glycidoxypropylmethyldimethoxysilane, T-glycidoxypropylmethyljethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

Furthermore, among the compounds of general formula (1), those other than those in which R1 has an epoxy group as a functional group (including those with a-0)
For example, the following can be used:

Methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, T-methacryloxypropyltrimethoxysilane, amethyltrimethoxysilane, 3-amino Propyltrimethoxysilane, 3-aminopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-chloropropyltrimethoxysilane, T-mercaptopropyltriethoxysilane, 3.3.3-)lifluoropropyltriethoxysilane Various trialkoxysilanes such as methoxysilane, triacyloxysilanes or trialkoxyalkoxysilane compounds.

The exemplified compounds of general formula (1) listed above are all S
There are three OR' groups bonded to the i atom (a+b=1)3
As a functional example, there are two OR'' groups (a+b=2)
Of course, corresponding difunctional compounds can also be used. Examples of corresponding difunctional compounds include dimethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, methylvinyldimethoxysilane, and dimethyljethoxysilane.

The compound of general formula (1) may be used alone, or two or more may be used in combination depending on the purpose.

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

Furthermore, it is also possible to use a corresponding tetrafunctional compound of a+b=o in combination. Examples of corresponding tetrafunctional compounds include methyl silicate, ethyl silicate, isopropyl silicate, n-propyl silicate, n-butyl silicate, t-butyl silicate, 5ec-butyl silicate, and the like.

The compound of general formula (1) may be used as is, but
It is desirable to use it as a hydrolyzate for the purpose of increasing the reaction rate and lowering the curing temperature. When using two or more compounds with the same functional number among di- to tetrafunctional compounds, or when using two or more compounds with different functional numbers together, they may be used together after hydrolysis, or they may be used together after hydrolysis. Co-hydrolysis may be carried out in combination beforehand. Hydrolysis liberates an alcohol called HOR', and the compound of general formula (1) is converted into the corresponding silanol: OHR'' 0H-5i -OH or 0H-5i - 0H1ll or R2R1. Silanol undergoes rapid dehydration condensation and becomes an oligomer. Therefore, in order for this reaction to proceed sufficiently,
After hydrolysis, it may be allowed to stand (cure) for 1 to 24 hours.

b: A composite sol of colloidally dispersed tin oxide and tungsten oxide is used.

The ratio of tin oxide and tungsten oxide is 100% tin oxide
The amount is 2 to 100 parts by weight based on tungsten oxide.

Colloidally dispersed tin oxide sol, tungsten oxide sol, and composite sol of tin oxide and tungsten oxide are each well known, and some are commercially available.

Tin oxide sol is preferable because it has a high refractive index, and exists as a sol alone, but due to the essential properties of the substance, it cannot exist stably with component (a), and tungsten oxide sol has a relatively low refractive index. It can exist alone as a sol and stably exist with component (a), but
A coating composition formed from component (a) and tungsten oxide sol has a problem in water resistance.

By using a composite sol of tin oxide and tungsten oxide, the drawbacks of both can be compensated for and desirable properties can be brought out. That is, it is possible to obtain a coating composition in which both component (a) exists stably, there is no problem in water resistance, and the refractive index is high.

The proportion of tin oxide and tungsten oxide is such that 2 to 100 parts by weight, preferably 5 to 50 parts by weight of tungsten oxide is used per 100 parts by weight of tin oxide in order to take advantage of their respective strengths and compensate for their shortcomings. If the ratio is smaller than this, there will be a lack of stability when mixed with component (a), and if the ratio is larger than this, there will be problems with the water resistance of the coating composition.

The particle size of the sol is preferably 1 to 200 mμ, especially 5 to 100 mμ; if it is smaller than this, it is difficult to manufacture.
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 and the transparency and smoothness of the coating film will be reduced).

A sol is a colloidal solution in which fine particles of a composite of tin oxide and tungsten oxide are dispersed in water, an organic solvent, or a mixed solvent of both, and it is useful to stabilize it by adding an appropriate alkali, especially an organic amine. It is.

C-II: The curing catalyst (C) is used to shorten the time required to polymerize component (a) and form a coating film with a three-dimensional network structure.
They are used as necessary (however, it is not preferable to use one that affects the stability of the coating composition), and for example, the following are used.

(1), Amines: monoethanolamine, jetanolamine, isopropanolamine, ethylenediamine, isopropylamine, diisopropylamine, morpholine, triethanolamine, diaminopropane, aminoethylethanolamine, dicyandiamide, triethylenediamine, 2
-Ethyl-4 methylimidazole.

(2), General formula of various metal complex compounds = AIX1. Y3-. l (However, in the formula, X is OL (L is a lower alkyl group), Y
is the general formula M' COCHt COM ” (M, M
t is at least one selected from a lower alkyl group) and M'C0CH, a ligand derived from CO2 abundance, and n is O
or 1 or 2).

From the viewpoint of solubility, stability, and catalyst curing, particularly useful chelate compounds include aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum di-n-butoxide monoethylacetoacetate, Aluminum-di-1so-propoxide-monomethylacetoacetate and the like.

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, tetramypropoxytitanium.

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

(5), perchlorate: Magnesium perchlorate, ammonium perchlorate.

(6) Organic acids or their anhydrides: malonic acid, succinic acid, tartaric acid, adipic acid, azelaic acid, maleic acid, 0-phthalic acid, terephthalic acid, fumaric acid, itaconic acid, oxaloacetic acid, anphosuccinic acid, anhydride Maleic acid, itaconic anhydride, 1,2-dimethylmaleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, naphthalic anhydride.

(7), Lewis #: 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 not be used alone, but may be used in combination of two or more. Particularly when component (a) has an epoxy group, a catalyst that also serves as a ring-opening polymerization catalyst for the epoxy group may be used.

In particular, aluminum chelate compounds are one of the preferred catalysts.

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, etc. are used. In the coating composition of the present invention, component (b) is contained in an amount of 10 to 400 parts by weight (solid content) per 100 parts by weight (solid content) of component (a).
Preferably, 50 to 250 parts by weight (solid content) are used, and (a
It is appropriate to use 0100001 to 20 parts by weight of component (C) per 100 parts by weight (solid content) of components () and (b).

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, for the purpose of improving adhesion to the substrate (molded object) to be coated, improving weather resistance, etc., or for the purpose of improving the weather resistance of the coating composition, Various additives may be used in combination for the purpose of improving stability.

Examples of additives include pH regulators, viscosity regulators, leveling agents, matting agents, dyes, pigments, stabilizers, ultraviolet absorbers, and antioxidants.

In addition, an epoxy resin or other organic polymer may be used in combination for the purpose of improving the dyeability of the coating film.

Epoxy resins include polyolefin epoxies commonly used for paints and casting, cyclopentadiene oxide, cyclohexene oxide, alicyclic epoxy resins such as polyglycidyl esters, polyglycidyl ethers, epoxidized vegetable oils, and novolaks. Examples include epoxynophoranc, which is made of type phenolic resin and epichlorohydrin, and furthermore, glycidyl methacrylate and methyl methacrylate copolymers.

Other organic polymers include, for example, polyols,
There are cellulose resins, melamine resins, etc.

In order to improve the flow during application, improve the smoothness of the coating film, and lower the coefficient of friction on the coating surface, various surfactants can be used in combination with the coating composition, especially dimethylsiloxane. Block or graft copolymers of and alkylene oxide, as well as fluorine-based surfactants, etc., 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 of the invention are applied in particular to plastic moldings. In terms of materials for molded products, examples include polymethyl methacrylate and its copolymers, acrylonitrile-styrene copolymers, polycarbonates, cellulose acetate, polyvinyl chloride, polyethylene terephthalate, epoxy resins, unsaturated polyester resins, polyurethane resins, CR The composition of the present invention is applied to a polymer of -39 and the like.

In terms of form, the composition of the present invention is applied to blocks, wires, films, and the like.

In terms of function, molded products include optical products, especially camera lenses,
The composition of the present invention is applied to spectacle lenses, reflective mirrors, prisms, and the like.

The composition of the present invention is particularly useful as a scratch-preventing film for "eyeglass lenses" molded from resin with a medium to high refractive index of na=1.53 or more.

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

As the application means, usual coating methods 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 that becomes the base molded product is cast-polymerized to form a plastic molded product,
After applying the composition of the present invention to a molded article, the surface of the uncured coating film may be brought into close contact with a mold, and the coating film may 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. The heating temperature is about 50-200°C, preferably 80-1
A sufficient effect can be obtained at 40°C.

The thickness of the coating film after drying is generally from 0.3 to 30 microns, preferably from 0.5 to 10 microns.

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

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to this.

〔Example〕

A: 1= 248 parts by weight of T-glycidoxypropylmethyljethoxysilane was charged into a reaction vessel equipped with a rotor, and while stirring vigorously using a magnetic stirrer, 0.0
36 parts by weight of a 5N aqueous hydrochloric acid solution was added at once.

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

To the obtained hydrolyzate, 5 ethanol was added as component (d).
After adding 6.6 parts by weight and 53.4 parts by weight of ethylene glycol, 4.71 parts by weight of aluminum acetylacetonate was added as component (c) and thoroughly mixed and dissolved to prepare preliminary composition A. .

B: 212.4 parts by weight of T-glycidoxypropyltrimethoxysilane was charged into a reaction vessel equipped with a rotor, the temperature inside the vessel was kept at 10°C, and the mixture was stirred vigorously using a magnetic stirrer. ,o,.

48.6 parts by weight of 1N aqueous hydrochloric acid solution was gradually added dropwise.

Immediately after the completion of the dropwise addition, cooling was stopped to obtain a hydrolyzate corresponding to component (a) in the form of a uniform, colorless and transparent solution.

To the obtained hydrolyzate, ethanol 7 was added as component (d).
After adding 7.1 parts by weight and 37.7 parts by weight of ethylene glycol, 7.65 parts by weight of aluminum acetylacetonate was added as component (c) and thoroughly mixed and dissolved to prepare preliminary composition B.

In a cone glass container, add the precompositions A and B prepared in (1) and (2) above to the parts by weight (not solid content) listed in Table 1 below.
Weigh and pour into it a commercially available composite sol of tin oxide and tungsten oxide (water dispersion sol, average particle size: lO~
15mμ, ratio of tin oxide and tungsten oxide: 100
weight part/40 weight part, solid content 20%) to 200 weight part (
(not solid content), silicone surfactant 0.45
By adding parts by weight and thoroughly stirring and mixing, a uniform, colorless and transparent coating composition in the form of a solution was prepared.

(9) - Prepare a commercially available polycarbonate eyeglass lens with a refractive index nt = 1.59, and use the immersion method (with a pulling speed of 10 cm).
/min) and apply the above coating composition at 100"C
The coating film was cured by heat treatment for 2 hours.

Concave-tffi± The lens with the cured coating obtained in the previous section (4) was subjected to the following test,
The performance of the coating film was evaluated.

(a) Friction resistance test The coating surface was rubbed with steel wool #0000 to examine the resistance to scratching. The evaluation was conducted as follows.

◎・・・・・・No scratches even if rubbed strongly.

O: Quite strong (friction may cause slight damage).

×・・・Even weak friction can cause damage.

By the way, the evaluation of the lens without a coating film was ×.

(b) Appearance A general-purpose antireflection film was formed by vacuum deposition on the coating film cured in the previous item (4), and the unevenness of reflected color was examined with the naked eye and evaluated as follows.

◎...No unevenness in reflected color O... Slightly noticeable ×... Significant I (c) A lens with an adhesive cured coating is placed in hot water at 90"C. After soaking for 2 hours, cut lines are made in the vertical and horizontal directions at IW intervals on the coating surface using a knife to make 100 goban marks, and then cellophane adhesive tape (product name) "Cello Tape" manufactured by Nichiban Co., Ltd. ) was strongly pasted. Holding one end of the tape in one's hand, it was rapidly peeled off in a 90-degree direction, and the number of gobbles on the paint film that came off was determined. The number of peeled gobbles, X, was taken as the numerator. It is expressed as X/100, and the smaller X is, the better the adhesion is.

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

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

[Comparative Example 1] In the example, commercially available silica sol (methanol dispersion sol,
The coating composition of this example was prepared and evaluated in substantially the same manner as in the example except that the average particle diameter = 13±ImB and the solid content was 20%.

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

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

Table I [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 coating a plastic eyeglass lens with a medium to high refractive index, and an antireflection film is formed on the hard coating film, there is no unevenness in reflected color.

(2) The coating film has excellent scratch resistance, surface hardness, abrasion resistance, flexibility, transparency, heat resistance, water resistance, etc.

(3) The paint film has a large elongation (even if the base material bends, the risk of cracking on the paint film surface is extremely small).

(4) Shrinkage during curing is small, and there are no problems such as curling, especially when applied to thin films.

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

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

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

(8) Good adhesion of antireflection films, metal vapor deposition films, etc. to paint films.

(9) The coating surface has good sliding properties (low coefficient of friction).

Claims (1)

[Claims] (a) General formula: R^1_aR^2_bSi(OR^3)_4_-_(_
a_+_b_)...(Formula I) (wherein, R^1 is a functional group or a carbon number 4 having an unsaturated double bond
-14 organic group, R^2 is a hydrocarbon group or halogenated hydrocarbon group having 1 to 6 carbon atoms, and R^3 is an alkyl group, alkoxyalkyl group, or acyl group having 1 to 4 carbon atoms. is a group, a and b are each 0 or 1, and a+b is
1 or 2. ) an organosilicon compound or its hydrolyzate; (b) a composite sol of colloidally dispersed tin oxide and tungsten oxide; and optionally (c) a curing catalyst; and optionally (d) a solvent; A coating composition characterized by: