JPH06136292A - Composition for coating carbonate article and polycarbonate article - Google Patents

Abstract

PURPOSE:To provide a coating composition for carbonate article comprising a (meth)acrylic functional group-containing silanol, a polyfunctional (meth) acrylate, a colloidal metal oxide, a photopolymerization catalyst and an Al compound, excellent in adhesion, and giving coating films having good hardness, adrasion resistance and moisture resistance. CONSTITUTION:The composition for hard coatings, etc., comprises (A) a (math) acrylic functional group-containing silanol of formula I[R<1> is H, methyl; R<2> is (substituted) monovalent hydrocarbon; n is an integer of 0-2] (e.g. 3- acryloyloxypropyldimethoxysilanol), (B) a polyfunctional (meth)acrylate of formula II (R<3> is polyfunctioned hydrocarbon residue, the ester residue of a polyhydric alcohol with a polybasic acid; m is the valency of the residue and an integer of >=2), (C) a colloidal metal oxide (e.g. silica), (D) a photopolymerization initiator (e.g. benzoin), and (E) an aluminum compound (e.g. aluminum chloride).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polycarbonate article coating composition used for hardcoating a polycarbonate article, and a polycarbonate article having a cured coating of the composition formed thereon.

[0002]

2. Description of the Related Art Polycarbonate resin is widely used as a transparent plastic material because it is excellent in impact resistance, heat resistance, moisture resistance, cold resistance and transparency. Since it has a low hardness, it is easily scratched and has poor weather resistance.
Therefore, a method of coating the surface of the polycarbonate molded article with various coating agents has been proposed for the purpose of improving these drawbacks, but none of them is sufficiently satisfactory.

For example, as a method for making the surface of a polycarbonate molded article less likely to be scratched, a method of applying a (meth) acrylic acid ester to cure it with ultraviolet light, or an acrylic primer is applied and dried, and then an organopolysiloxane coating agent is applied. A method of coating and heating and curing is known (Japanese Patent Publication No. 4-2614, Japanese Patent Application Laid-Open No. 3-28763).
No. 4, etc.).

However, the former method has the drawbacks that the surface hardness, water resistance and weather resistance of the cured coating are not sufficiently satisfactory, and the shrinkage associated with curing is too large. On the other hand, the latter method has poor workability because the primer coat and the top coat are applied twice, and the surface is liable to whiten unless it is applied in a humidity-controlled working environment. It is scarce and has the drawback that the substrate is easily deformed by heat during curing.

As a method for improving the above method, a method using an ultraviolet-curable organopolysiloxane is known. For example, JP-A-61-111330 discloses an acrylic functional silicone resin composition. ing. However, the cured film of this composition is brittle and is inferior in scratch resistance. Further, JP-A-59-204669 discloses that colloidal silica is added to a methacryloxysilane hydrolyzate and a polyfunctional acrylate system to improve scratch resistance. However, this composition also has poor adhesion to a polycarbonate resin and has a drawback that it is poor in water resistance and moisture resistance because the silanol groups of the methacryloxysilane hydrolyzate remain.

On the other hand, Japanese Patent Publication No. 63-65115 proposes a method of ring-opening polymerization of an epoxy group-containing silane hydrolyzate using a photolytic catalyst of an onium salt to obtain a hard coating having excellent moisture resistance. Has been done. However, this coating is also susceptible to photodegradation due to the effect of residual hydroxyl groups, and is therefore unsuitable for exterior applications (building materials, vehicle window materials, etc.) that require weather resistance.

Further, for the purpose of improving the adhesiveness with a polycarbonate resin, a method of obtaining a hard coating by irradiating a photopolymerizable functional group-containing ladder type polysiloxane having a small shrinkage rate with ultraviolet rays during curing of the organopolysiloxane is provided. Japanese Patent Laid-Open No. Hei 4
No. 33936. Since this photopolymerizable functional group-containing ladder-type polysiloxane has a high degree of polymerization and a small volume decrease upon curing, defects such as cracks can be ameliorated. It has a poor anchoring effect on the resin, is not satisfactory in water resistance and alkali resistance, and is also inferior in scratch resistance. Moreover, since the ladder-type polysiloxane has poor productivity and low yield, it is not an industrially suitable material.

Therefore, it is difficult to say that the polycarbonate article having the above-mentioned UV-curable coating has sufficiently satisfactory characteristics, and therefore, it is desired to develop a polycarbonate article coated with the UV-curable resin excellent in various characteristics. It was rare.

The present invention has been made in order to meet the above-mentioned demands. It is easily cured by irradiation with ultraviolet rays for a short time, has good adhesiveness to a polycarbonate resin, and has high hardness, scratch resistance, and abrasion resistance. It gives a cured coating with excellent solvent resistance, weather resistance, alkali resistance, and moisture resistance. In particular, it has good adhesion even when immersed in an alkaline aqueous solution or boiling water, and it does not require the complexity of primer coating and other workability. It is an object of the present invention to provide an excellent polycarbonate article coating composition and a polycarbonate article having such a cured coating formed thereon.

[0010]

Means and Actions for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, (A) a (meth) acryl group-containing silanol represented by the following general formula (1), (B) ) Polyfunctional (meth) acrylate represented by the following general formula (2), (C) colloidal metal oxide,
When a UV-curable and condensation-reaction-curable composition containing (D) a photopolymerization initiator and (E) an aluminum compound is applied to a polycarbonate molded product, this coating film is easily cured by irradiation with UV light for a short time. In this case, the silanol group of the component (A) is effectively condensed by the catalytic action of the aluminum compound of the component (E) to be crosslinked by the heat of the ultraviolet ray irradiation at this time, and the condensation of the silanol group is more complete. In order to achieve the above, it was found that it is effective to perform heat treatment for a short time before or after the irradiation of ultraviolet rays.
The coating film cured in this way has high hardness and excellent scratch resistance, abrasion resistance, solvent resistance, weather resistance, alkali resistance, and moisture resistance, as well as excellent adhesion to polycarbonate molded products. Therefore, the present invention has been completed by finding out that the material has a property.

[0011]

[Chemical 3] (However, R ¹ is a hydrogen atom or a methyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 0 to 2.)

[0012]

[Chemical 4] (However, R ¹ has the same meaning as described above, R ³ is a polyvalent hydrocarbon residue bonded to different carbon atoms or an ester residue of a polyhydric alcohol and a polybasic acid, and m is It is a valence and is an integer of 2 or more.)

Accordingly, the present invention provides (A) a silanol containing a (meth) acrylic functional group represented by the above general formula (1), (B) a polyfunctional (meth) acrylate represented by the above general formula (2), (C) colloidal metal oxide,
Provided is a composition for coating a polycarbonate article, which comprises (D) a photopolymerization initiator and (E) an aluminum compound, and a polycarbonate article having a cured coating of the composition formed thereon.

The present invention will be described in more detail below. The component (A) in the present invention is a (meth) acrylic functional group-containing silanol represented by the following general formula (1), and a photopolymerization initiator ((D) The (meth) acrylic group is photopolymerized depending on the component) and forms a main component when a cured coating is formed. Further, the silanol group is condensed by the aluminum compound ((E) component) by heat during ultraviolet irradiation or during heating for a short time before and after ultraviolet irradiation, thereby forming a siloxane skeleton and simultaneously contributing to adhesion to the substrate. It is a thing.

[0015]

[Chemical 5]

Here, R ¹ is a hydrogen atom or a methyl group. Further, n is an integer of 0 to 2, and the compound of the formula (1) has at least one OH group,
Particularly, the compound represented by the following formula (1a) or (1b) is preferably used.

[0017]

[Chemical 6]

R ² is a substituted or unsubstituted monovalent hydrocarbon group. Preferred is an alkyl group having 1 to 6 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and a butyl group.

Specifically as the silane of the above formula (1),
3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. in the presence of a lower alcohol in a stoichiometric amount of water with hydrochloric acid or acetic acid. Those obtained by hydrolysis under dilute acidic conditions such as the above can be used. The above silanes may be used alone or in combination of two or more.

Further, a cohydrolyzed product of the above silane and another silane can be used. In this case, other hydrolyzable silanes include, for example, tetramethoxysilane, tetraethoxysilane, methylpolysilicate, ethylpolysilicate, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, phenyltrisilicate. Methoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3- Alkoxysilanes such as chloropropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, and 2-perfluoroalkylethyltrimethoxysilane are listed. One type of al alone or in combination of two or more kinds may be used.

Next, the component (B) is a polyfunctional (meth) acrylate represented by the following general formula (2), which is radically polymerized with the component (A) to improve the adhesion with the polycarbonate and the brittleness of the coating. It is the ingredient to do.

[0022]

[Chemical 7]

Here, R ¹ is a hydrogen atom or a methyl group. R ³ represents a polyvalent hydrocarbon residue bonded to different carbon atoms or an ester residue of a polyvalent alcohol and a polybasic acid, and m is a valence of the residue and is an integer of 2 or more.

In this case, the polyfunctional (meth) acrylate having polyvalent hydrocarbon residues bonded to different carbon atoms can be obtained by an esterification reaction between an organic polyhydric alcohol and (meth) acrylic acid. Examples of the organic polyhydric alcohol include ethylene glycol, diethylene glycol, 2,2,4-trimethyl-
1,3-pentanediol, propylene glycol, dipropylene glycol, triethylene glycol, 1,
4-cyclohexyldimethanol, neopentyl glycol, pentaerythritol, trimethylolpropane, trimethylolethane, glycerin, 1,4-butanediol, 2,3-butanediol, triethanolamine, 1,2,6-hexanetriol , 1,3-propanediol, 1,6-hexanediol and the like, and one or more of these can be used.

As the ester residue composed of polyhydric alcohol and polybasic acid, the above-mentioned organic polyhydric alcohol and phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, isophthalic acid, terephthalic acid, hymic acid are mentioned. The residue of an ester composed of one or more selected from polybasic acids such as succinic acid, adipic acid, maleic acid, fumaric acid, itaconic acid, pyromellitic acid and trimellitic acid, or acid anhydrides thereof. A group can be mentioned.

Specific examples of the polyfunctional (meth) acrylate as the component (B) include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate. Acrylate, ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neopentyl glycol di (meth)
Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane di (meth) acrylate,
In addition to trimethylolethanedi (meth) acrylate, the following structural formulas can be mentioned.

[0027]

[Chemical 8]

The amount of component (B) added is the same as component (A) 1
5 to 200 parts by weight, especially 10 to 10 parts by weight, relative to 00 parts by weight
It is preferably 0 part by weight. If it is less than 5 parts by weight, the adhesion to the polycarbonate may not be obtained, while if it exceeds 200 parts by weight, the hardness of the coating film may be low and the weather resistance may be poor.

Next, the colloidal metal oxide as the component (C) is a component which imparts surface hardness and abrasion resistance to the cured coating, which is usually dispersed in water or an organic solvent. From the viewpoint of compatibility in the system of the composition, those dispersed in an organic solvent are preferably used. The average particle size of the colloidal metal oxide is 1 to 100 mμ, especially 3
It is preferable that the average particle diameter is less than 1 mμ, and the surface hardness cannot be increased. If the average particle size exceeds 100 mμ, the transparency of the coating may be lost.

As such a colloidal metal oxide, specifically, one or more of silica, titania, antimony oxide, tin oxide, tungsten oxide and the like can be used, but particularly economically inexpensive. Colloidal silica is preferably used. Further, in order to match the refractive index with that of the polycarbonate as the base material, a sol of titania, antimony oxide, tin oxide or the like can be used, and a mixed crystal sol, a mixed sol or the like can also be used. Examples of the mixed crystal sol include antimony oxide / silica sol, titania / silica sol, cerium oxide / titania sol, iron oxide / titania sol, tungsten oxide / tin oxide sol, and the like.

The amount of the colloidal metal oxide compounded is
30 to 1 as sol solid content based on 100 parts of component (A)
50 parts, especially 50 to 100 parts is preferable, and 3
If it is less than 0 part, the abrasion resistance of the coating may be insufficient, and if it exceeds 150 parts, the coating may be too brittle and the adhesion to the substrate may be poor.

Further, in the present invention, it is necessary to blend a photopolymerization initiator as the component (D) in order to cure the components (A) and (B) with ultraviolet rays. Specific examples of the photopolymerization initiator include benzoin, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, and 2-hydroxy. −
Examples include 2-methyl-1-phenylpropan-1-one, benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4-trimethylsilylbenzophenone, 4-trimethylsilyl-4′-dimethylaminobenzophenone and 4-methoxybenzophenone. These may be used alone or in admixture of two or more. Of these, it is particularly preferable to use a liquid compound in view of compatibility with the components (A) to (C).

In this case, the compounding amount of the photopolymerization initiator is
It is preferably 0.01 to 20 parts, especially 0.1 to 10 parts, relative to 100 parts of the component (A). Compounding amount 0.0
If it is less than 1 part, the sensitizing effect is poor, and tack may remain in the coating film, and if it exceeds 20 parts, the coating may become soft and the storage stability of the coating solution may deteriorate.

Next, the aluminum compound as the component (E) is for promoting the condensation reaction of the silanol groups as the component (A). The aluminum compound is preferably one that does not impair the photosensitizing property of the photopolymerization initiator, and particularly, a Lewis acid such as aluminum chloride, aluminum perchlorate, an aluminum complex compound, or an aluminum alkoxide is effective. Specific examples of such an aluminum compound include the following compounds.
The seeds may be used alone or in combination of two or more.

[0035]

[Chemical 9]

The blending amount of the aluminum compound is
With respect to 100 parts of the component (A), it is preferably 0.01 to 2 parts, and particularly preferably 0.05 to 1 part. If it is less than 0.01 part, the condensation accelerating action may be poor, and it exceeds 2 parts. If so, the storage stability of the coating solution may deteriorate.

Here, in the present invention, by utilizing the heat generated at the time of ultraviolet ray irradiation or by heating before and after the ultraviolet ray irradiation, the aluminum compound can efficiently remove the silanol groups remaining in the component (A). It can be condensed. As a specific example, after irradiation with ultraviolet rays, 50 to 1
It is preferable to post-cure at 20 ° C. for about 1 to 10 minutes, which makes it possible to obtain a coating having high hardness, abrasion resistance, and scratch resistance. Adhesion, water resistance,
A film having excellent weather resistance can be formed.

In the present invention, in addition to the above-mentioned aluminum compounds, examples of silanol group condensation accelerators include sodium acetate, trimethylammonium hydroxide, tetramethylammonium hydroxide, tetrabutylphosphonium hydroxide, zinc octylate, and diaza. Bicycloundecene / acetate, choline / acetate, etc. may be optionally added as long as the effects of the present invention are not impaired.

In the present invention, in order to make the composition a stable coating liquid, an organic solvent such as a lower alcohol which does not attack the polycarbonate is added as the component (F),
It is preferably a solution. Examples of the organic solvent such as lower alcohol include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, propyl cellosolve, diacetone alcohol and the like, and these may be used alone or in combination of two or more. Can be used as a mixture of Further, this organic solvent is preferably used so as to adjust the non-volatile content in the composition to about 2 to 50%, and may be used in an arbitrary blending amount depending on the coating film thickness.

In the composition of the present invention, as an optional component, a weather resistance improver, a silicone modified polyether leveling agent, a thickener, a colorant, an antistatic agent, etc. are added as long as the ultraviolet curability is not impaired. They may be added alone or in combination. In addition, an antiaging agent such as hindered amine or hindered phenol may be optionally added to the extent that it does not hinder ultraviolet curing. In addition, it is effective to optionally add an ultraviolet absorber and a stabilizer.

The polycarbonate article of the present invention is obtained by applying the above-mentioned coating composition to a polycarbonate substrate and curing it to form a cured coating on the polycarbonate article. As the coating method, flow coating, dip coating,
A usual method such as spray coating or spin coating can be applied, and it is usually suitable to apply the layer to a thickness of 0.5 to 5 μm. Then, after drying the coating film by natural drying or heating, it is irradiated with ultraviolet rays for 5 to 300 seconds with a light source such as a high pressure mercury lamp, preferably at an irradiation amount of 20 to 200 W / cm ² , to obtain a hard adhesive having excellent adhesiveness. A coating can be obtained. Further, for the purpose of further improving the durability, in order to completely convert the silanol groups in the remaining component (A) into siloxane, post-curing may be performed for a short time after the irradiation of ultraviolet rays.

[0042]

The composition for coating a polycarbonate article according to the present invention has excellent adhesion to a polycarbonate article without a primer layer, and has high hardness, scratch resistance and abrasion resistance.
A hard coating having excellent solvent resistance and moisture resistance can be applied, and the polycarbonate article on which the hard coating is applied is suitably used as an exterior material such as a building material or a vehicle window material, or an optical material.

[0043]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 17.0 g of 3-acryloxypropyltrimethoxysilane and 2 of isobutyl alcohol
To a mixture with 7.0 g, 4.2 g of 0.05 N dilute hydrochloric acid was added to 5 g.
Dropwise over 4 hours at -10 ° C, followed by MA-ST20
After adding 26.5 g (Nissan Chemical Co., Ltd., colloidal silica, non-volatile content 30%), it was aged at room temperature for 4 hours. Darocur 1116 (manufactured by Merck & Co., photopolymerization initiator, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one) 0.2 g, aluminum trisacetylacetonate 0.1 g, tris. 5.0 g of methylolpropane triacrylate and 28.0 g of isobutyl alcohol were added and filtered to prepare coating agent-1.

Example 2 Example 1 was repeated except that Sun Colloid AMT-130S (manufactured by Nissan Chemical Industries, Ltd., antimony pentaoxide sol, nonvolatile content 30%) was used in place of MA-ST20 of Example 1. Similar to coating agent-2
Was prepared.

Example 3 A mixture of 16.0 g of 3-acryloxypropyltrimethoxysilane, 3.4 g of tetramethoxysilane and 27.0 g of isobutyl alcohol, to which 5.8 g of 0.05N dilute hydrochloric acid was added dropwise was used. A coating agent-3 was prepared in the same manner as in Example 1 except that the above was used.

Comparative Example 1 Example 1 except that trimethylolpropane triacrylate in Example 1 was not blended.
A coating agent-4 was prepared in the same manner as in.

Comparative Example 2 A coating agent-5 was prepared in the same manner as in Example 1 except that neither trimethylolpropane triacrylate nor aluminum trisacetylacetonate in Example 1 was blended.

Comparative Example 3 Example 1 except that the aluminum trisacetylacetonate in Example 1 was not added.
A coating agent-6 was prepared in the same manner as in.

Comparative Example 4 A mixture of 149 g of 3-methacryloxypropyltrimethoxysilane, 428 g of methyltrimethoxysilane, 108 g of 0.05% by weight hydrochloric acid in water and 0.01 g of p-methoxyphenol was kept at 60 ° C. for 30 minutes. Then, after reacting at 70 ° C. for 1 hour, 0.9 g of N-butylamine was added dropwise and aged for 1 hour. After that, 0.5 g of formic acid was added dropwise and kept at 70 ° C. for 30 minutes to cool,
After dehydration with anhydrous sodium sulfate, the solvent was distilled off with an evaporator.
A methacryloxypropyl / methyl ladder polysiloxane was obtained. 35 parts of this resin, 45 parts of pentaerythritol tetraacrylate, 10 parts of trimethylolpropane triacrylate, 10 parts of N-vinyl-2-pyrrolidone
Part, benzophenone 3 parts, and ethyl p-dimethylaminobenzoate 3 parts were mixed to prepare coating agent-7.

The coating agents 1 to 7 obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were applied to a polycarbonate plate with a bar coater (No. 20), air-dried for 10 minutes, and then 80 W / cm ² Irradiate UV light from two high-pressure mercury lamps at a distance of 8 cm for 30 seconds to coat 1
Samples Nos. 4 to 4 were heated and cured at 100 ° C. for 2 minutes to prepare test pieces, while coating agents Nos. 5 to 7 were not post-cured, but test pieces were prepared. These coatings were evaluated by the following methods. The results are shown in Table 1. Adhesiveness: Cross-cutting was performed with 11 knives at intervals of 1 mm in length and width, a cellotape (manufactured by Nichiban Co., Ltd.) peeling test was performed, and remaining squares were counted. Scratch resistance: about 500 using # 0000 steel wool
The coating was rubbed 10 times with a load of g, and the scratched state was visually evaluated according to the following criteria. ◯: Almost no scratches Δ: Slight scratches ×: Many scratches Abrasion resistance: Taber abrasion test (CS-10 abrasive paper, 50
The haze (%) of the coating film after 0 g, 20 times) was measured with a haze meter. Solvent resistance: Xylene was impregnated and the coating was rubbed with absorbent cotton 100 times, and the appearance was visually evaluated according to the following criteria. ◯: No abnormality Δ: Slight peeling of coating film ×: Full peeling of coating film Moisture resistance: Adhesion after immersion in pure water at room temperature for 1 week was evaluated by a cellophane tape peeling test.

[0052]

[Table 1] From the results in Table 1, it was confirmed that the compositions of Examples 1 to 3 gave coatings excellent in adhesion, scratch resistance, abrasion resistance, solvent resistance, and moisture resistance.

Claims (2)

[Claims] 1. (A) A silanol containing a (meth) acrylic functional group represented by the following general formula (1): (However, R ¹ is a hydrogen atom or a methyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 0 to 2.) (B) A compound represented by the following general formula (2). Functional (meth) acrylate, embedded image (However, R ¹ has the same meaning as described above, R ³ is a polyvalent hydrocarbon residue bonded to different carbon atoms or an ester residue of a polyhydric alcohol and a polybasic acid, and m is It is a valence and is an integer of 2 or more.) (C) Colloidal metal oxide, (D) Photopolymerization initiator,
(E) A composition for coating a polycarbonate article, which comprises an aluminum compound. 2. A polycarbonate article having a cured coating of the composition of claim 1.