JPH0764941B2 - Transparent coated molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to scratch resistance, abrasion resistance, impact resistance, chemical resistance,
The present invention relates to a transparent coated molded article excellent in flexibility, heat resistance, light resistance, weather resistance and the like.

[Conventional technology]

Plastic molded articles, especially polycarbonate and transparent plastic molded articles typified by polymethylmethacrylate, are widely used as a substitute for inorganic glass products, taking advantage of their advantages such as light weight, easy workability and impact resistance. On the other hand, it has the drawbacks of insufficient hardness and being easily scratched, being easily immersed in a solvent, being charged and absorbing dust, being deteriorated by light and being colored, and so inorganic glass for application to window glass sheets, etc. Was unsatisfactory in practice compared to.

Many attempts have already been proposed to improve these drawbacks. For the purpose of improving scratch resistance and chemical resistance, a method of coating an inorganic hard substance such as SiO _{2 on the} surface of a plastic substrate by vacuum vapor deposition (Japanese Patent Laid-Open No. 58-204031 and Japanese Patent Laid-Open No. 56-147830). Or a method of providing a polyorganosilane-based hard coat film or an acrylic hard coat film on the surface of a plastic substrate (JP-A-59-155437 and JP-A-59-174629), and further scratch resistance. In order to improve the property, a method of adding inorganic fine particles such as silica fine particles to the hard coat film has also been proposed (Japanese Patent Laid-Open No. Sho 61-242)
59-78240, JP-A-59-89368). Further, JP-A-56-84729 discloses a coating composition containing various inorganic oxides containing titania sol and its application to an antireflection film.

On the other hand, as a means for preventing the deterioration of the plastic substrate due to light, a method of adding a stabilizer such as an antioxidant or an ultraviolet absorber to the substrate or the above-mentioned hard coat film is used.

[Problems to be solved by the invention]

However, although the method of coating the inorganic hard material by vacuum vapor deposition is effective for improving the surface hardness, it has the drawback of being inferior in adhesion and heat resistance.

Further, the method of applying a polyorganosilane-based or acrylic-based hard coat is excellent in surface hardness, adhesion, and heat resistance, but when exposed to light for a long time, deterioration of the base material due to light cannot be suppressed. However, there are problems such as yellowing, cracking, and poor adhesion.

Further, the conventional coated article using the titania sol composed of agglomerates has a problem that the coating itself turns yellow by irradiation with ultraviolet light.

The method of adding a stabilizer such as an antioxidant or an ultraviolet absorber to the base material or the hard coat film improves the light resistance, but the amount added is limited, and the transparency and scratch resistance are also limited. However, there is a drawback that the original performance of the base material and the hard coat film is deteriorated.

The present invention, the coating film absorbs ultraviolet light,
It is an object of the present invention to provide a transparent coated molding having excellent weather resistance, light resistance, strong adhesion, and high surface hardness.

[Means for solving problems]

The present inventors have the following configurations to achieve the above object.

That is, the present invention is a "transparent coated molded article characterized in that a coating comprising the following components A and B is provided on the surface of a transparent plastic substrate.

A. Organic matter-containing polymer B. Cubic shape in which L / D is 1 to 10 and L and D are 4 to 60 mμ, where L is the major axis length of the particle and D is the minor axis length. Alternatively, titanium oxide particles that are not rectangular parallelepiped aggregates. Regarding

Examples of the transparent plastic substrate in the present invention include acrylic resin, polycarbonate, diethylene glycol bisallyl carbonate polymer, acrylonitrile-styrene copolymer, cellulose acetate, polyvinyl chloride epoxy resin, etc., but are not particularly limited as long as they are transparent. .

The titanium oxide particles as the component B in the present invention are supplied as a colloidal dispersion in an organic solvent such as water and / or alcohol, but the titanium oxide particles in the present invention are titanium oxide dispersed in a dispersion medium. When the length of the long axis of the particle is L and the length of the short axis is D, L / D is 1 to 1
Since it is 0, preferably 1 to 2.5, it is cubic or rectangular parallelepiped, and is preferably present in an amount of 60% or more. Also, generally, the length L of the long axis is about 4 to 60 mμ,
The length D of the short axis is also about 4 to 60 mμ, and the individual titanium oxide particles are not aggregates but have a shape in which crystal particles of anatase having a size of 4 to 60 mμ grow in a cubic shape or a rectangular parallelepiped shape. Those that are present are preferable.

The major axis length L and the minor axis length D of the titanium oxide particles are
It is determined as follows. That is, the titanium oxide particles are observed with an electron microscope, and the longest length in the longitudinal direction is L. In addition, the length in the direction orthogonal to the longitudinal direction at the position of L / 2 in the longitudinal direction is defined as the length D of the minor axis. Such titanium oxide particles having an L / D of 1 to 2 are substantially cubic or rectangular parallelepiped.

The proportion of titanium oxide particles in the coating film in the present invention should be determined depending on the intended performance, the substrate to which it is applied, etc., but is preferably applied in the range of 5 to 75% by weight. That is, if it is less than 5% by weight, the effect of adding titanium oxide particles is not recognized, and if it exceeds 75% by weight, problems such as whitening of the coating film, cracking of the coating film, and poor adhesion occur.

The organic substance-containing polymer which is the component A in the present invention may be any polymer as long as it does not impair the transparency of the coating film.
Examples of usable polymers include polyvinyl butyral, polyvinyl alcohol, celluloses, melamine resins, epoxy resins, polysiloxane resins, acrylic resins and the like.

Among them, thermosetting resins are preferably used from the viewpoints of surface hardness, heat resistance, hot water resistance, chemical resistance, etc., and polysiloxane resins are particularly preferably used from the viewpoint of improving surface hardness. Typical examples of the composition capable of forming an organopolysiloxane include the organosilicon compound represented by the following general formula (I) and / or its hydrolyzate.

RR _a ¹ SiX _3-a (I) (where R is a carbon number of 1 to 10) organic group, R ¹ is a carbon number of 1
6 to a hydrocarbon group or a halogenated hydrocarbon group, X is a hydrolyzable group, and a is 0 or 1. ) Specific examples of these organosilicon compounds include:
Methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane , Vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane,
γ-chloropropyltriacetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyl Trimethoxysilane, γ-mercaptopropyltrimethoxyethoxysilane, γ-mercaptopropyltriethoxysilane, N-
β- (aminoethyl) -γ-aminopropyltrimethoxysilane, β-cyanoethyltriethoxysilane, methyltriphenoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, glycidoxymethyltrimethoxysilane, glycidoxy Methyltriethoxysilane, α-glycidoxyethyltrimethoxysilane, α-glycidoxyethyltriethoxysilane, β
-Glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β -Glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ
-Glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, γ-glycidoxypropyltrimethoxyethoxysilane, γ-glycidoxypropyltriphenoxysilane, α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyltriethoxysilane, β-glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxysilane, γ
-Glycidoxybutyltriethoxysilane, δ-glycidoxybutyltrimethoxysilane, δ-glycidoxybutyltriethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane, (3,4-epoxycyclohexyl) Methyltriethoxysilane, β- (3,4
-Epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltripropoxysilane, β- (3,4-epoxycyclohexyl) ethyl Tributoxysilane, β-
(3,4-Epoxycyclohexyl) ethyltrimethoxyethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriphenoxysilane, γ- (3,4-epoxycyclohexyl) propyltrimethoxysilane, γ-
Trialkoxysilanes such as (3,4-epoxycyclohexyl) propyltriethoxysilane, δ- (3,4-epoxycyclohexyl) butyltrimethoxysilane, δ- (3,4-epoxycyclohexyl) butyltriethoxysilane, triacyloxy Silane or triphenoxysilane or its hydrolyzate and dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-
Chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ- Aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane, α-glycidoxyethylmethyl Dimethoxysilane, α-glycidoxyethylmethyldiethoxysilane, β-glycidoxyethylmethyldimethoxysilane, β-glycidoxyethylmethyldiethoxysilane α-glycidoxypropylmethyldimethoxysilane, α-glycidoxypropylmethyldiethoxysilane, β-glycidoxypropylmethyldimethoxysilane, β-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane Silane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldipropoxysilane, γ-glycidoxypropylmethyldibutoxysilane, γ-glycidoxypropylmethyldimethoxyethoxysilane, γ-glycid Xypropylmethyldiphenoxysilane, γ-glycidoxypropylmethyldiacetoxysilane, γ-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylvinyl dimetho Sisilane, γ-glycidoxypropylvinyldiethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, γ-glycidoxypropylphenyldiethoxysilane, etc. Dialkoxysilane, diphenoxysilane or diacyloxysilanes or their hydrolysis The thing is an example.

These organosilicon compounds may be added alone or in combination of two or more. Particularly, for the purpose of imparting dyeability, it is preferable to use an organic silicon compound containing an epoxy group or a glycidoxy group. Alternatively, from the viewpoints of curing rate, easiness of hydrolysis, etc., C ₁ -C ₄ alkyl or alkoxyalkyl is preferably used as X.

These organosilicon compounds are preferably used after being hydrolyzed in order to lower the curing temperature and accelerate curing.

Hydrolysis is produced by adding pure water or an acidic aqueous solution such as hydrochloric acid, acetic acid, or sulfuric acid and stirring.
Furthermore, the degree of hydrolysis can be easily controlled by adjusting the amount of pure water or acidic aqueous solution added. At the time of hydrolysis, it is particularly preferable to add pure water or an acidic aqueous solution that is equimolar or more and 3 times or less the molar amount of the X group of the general formula (I) from the viewpoint of promoting the curing.

During the hydrolysis, alcohol or the like is generated, so it is possible to perform the hydrolysis without a solvent, but the hydrolysis is performed after mixing the organic silicon compound and the solvent for the purpose of making the hydrolysis more uniform. It is also possible. It is also possible to remove an appropriate amount of alcohol after hydrolysis under heating and / or reduced pressure for use depending on the purpose, and to add an appropriate solvent after that.

Examples of these solvents include alcohols, esters, ethers, ketones, halogenated hydrocarbons, and aromatic hydrocarbons such as toluene and xylene.
Alternatively, these solvents can be used as a mixed solvent of two or more kinds, if necessary. Further, depending on the purpose, it is possible to accelerate the hydrolysis reaction and further heat it to room temperature or higher in order to proceed the reaction such as precondensation, or to lower the hydrolysis temperature to room temperature or lower in order to suppress precondensation. It goes without saying that it is possible to do it.

In the present invention, a coating composition comprising titanium oxide fine particles and an organic matter-containing polymer as a main component is applied to the surface of a transparent substrate and cured by heating. It is possible to subject the substrate to various pretreatments for the purpose of improving water resistance. Particularly, effective means for the present invention include activated gas treatment, chemical treatment and the like.

In curing the coating composition of the present invention, various curing agents can be used in combination for the purpose of accelerating curing and curing at low temperature. As the curing agent, various epoxy resin curing agents or various organic silicon resin curing agents are used.

Specific examples of these curing agents include various organic acids and their acid anhydrides, nitrogen-containing organic compounds, various metal complex compounds or metal alkoxides, and organic carboxylates and carbonates of alkali metals. Various salts can be mentioned. These curing agents can be used as a mixture of two or more kinds. Among these curing agents, the aluminum chelate compounds shown below are particularly useful for the purpose of the present invention from the viewpoints of stability of the coating material and the presence or absence of coloring of the coating film after coating.

The aluminum chelate compound here is, for example,
Aluminum chelate compound represented by the general formula AlY _n Z _3-n.

However, in the formula, Y is OL (L is a lower alkyl group), Z is a ligand derived from a compound represented by the general formula M ¹ COCH ₂ COM ² (M ¹ and M ² are both lower alkyl groups), and a general ligand Formula M ³ COCH ₂ COO
It is at least one selected from the distributors derived from the compound represented by M ⁴ (M ³ and M ⁴ are both lower alkyl groups), and n is 0, 1 or 2.

As the aluminum chelate compound represented by the general formula AlY _n Z _3-n which is particularly useful as the curing agent of the present invention, various compounds can be mentioned, but solubility in the composition, stability, effect as a curing catalyst, etc. From the viewpoint of, aluminum acetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum-di-n-butoxide-monoethylacetoacetate, aluminum-di-iso-propoxide-monomethylacetoacetate and the like are preferable. is there. It is also possible to use a mixture of two or more of these.

As a method for applying the coating composition applied to the transparent substrate of the present invention, a commonly used coating method such as brush coating, dip coating, roll coating, spray coating, spin coating, or flow coating can be easily used. is there.

The coating film of the present invention can be obtained by coating and curing with the coating means, and the curing is mainly carried out by heat treatment. In addition, the heating temperature can be used in a considerably wider range than in the case of the conventional coating composition,
Good results are obtained at 250 ° C.

The film thickness of the coating film in the present invention is not particularly limited. However, from the viewpoint of maintaining adhesive strength and hardness, it is 0.
It is preferably used between 1 and 20 microns. More preferably, it is 0.4 to 10 microns. In addition, when applying the coating, various solvents are used to control workability and film thickness.
The diluent solvent used after being diluted includes water, alcohol, ester, ether, halogenated hydrocarbon and the like.

The coating obtained by the present invention has a large absorption for ultraviolet light around 300 nm to 380 nm, and since the coating itself hardly deteriorates, it is a substrate weak against ultraviolet light, for example, polycarbonate, polystyrene, halogen, chlorine, bromine,
It is expected that the surface hardness of the polymer containing iodine and the like will be increased and the weather resistance will be improved.

Therefore, the molded product of the present invention is not only for indoor use, but also for outdoor use such as window glasses of constructions, trains, automobiles, aircrafts, show windows, eyeglass lenses for sunglasses or straightening, light covers of automobiles, helmets, etc. Is also preferably applied.

〔Example〕

Examples will be described below, but the present invention is not limited thereto.

Example 1 (1) Preparation of coating composition (a) Preparation of γ-glycidoxypropyltrimethoxysilane hydrolyzate A reactor equipped with a rotor was charged with 95.3 g of γ-glycidoxypropyltrimethoxysilane. , Keep the liquid at 10 ℃, and stir it with a magnetic stirrer.
21.8 g is gradually added dropwise. After completion of dropping, stop cooling and
A hydrolyzate of glycidoxypropyltrimethoxysilane was obtained.

(B) Preparation of paint To the above-mentioned silane hydrolyzate, 105.5 g of methanol and 0.9 g of a silicon-based surfactant were added and mixed, and further water-dispersed colloidal titanium oxide sol (anatase crystalline titania sol, L / L
D = 2 Average particle size: about 10 mμ, solid content 10%) 337 g, and aluminum acetylacetonate 7.5 g were added and sufficiently stirred to obtain a coating composition.

(2) Preparation of Covered Molded Body A polycarbonate plate was used as a transparent base material, and after the primer treatment was performed in advance, the coating composition prepared in (1) above was dip coated at a pulling rate of 10 cm / min, and then, Pre-curing was performed at 82 ° C for 12 minutes, and after heating at 120 ° C for 2 hours, a coated molded body was obtained.

(3) Performance evaluation The performance of the obtained transparent composition was tested according to the following method. The results are shown in Table 1.

I. Adhesion test Put 100 pieces of crevices reaching the base of 1 mm on the surface of the coating with a steel knife from the top of the coating, and firmly attach cellophane adhesive tape (product name "Cellophane tape" manufactured by Nichiban Co., Ltd.) to 90 It was peeled off rapidly in the direction of the angle, and the presence or absence of peeling of the coating film was examined.

B. Scratch resistance test Rub with # 0000 steel wool to check scratch resistance. The judgment was performed as follows.

A: No scratches even with strong rubbing B ... Slight scratches with fairly strong rubbing C ... Scratches with weak rubbing c. Weather resistance test Exposed to ultraviolet rays for 100 hours with an accelerated weather resistance tester (trade name QUV manufactured by THE Q-PANEL COMPANY), and the yellowing YI value was determined by a color computer (manufactured by Suga Test Instruments Co., Ltd.).

Table 1 shows the difference in yellowing degree (ΔYI) before and after the test.

Comparative Examples 1 and 2 A water-dispersed colloidal titanium oxide sol (average particle size: about 50 mμ, solid content: 10%) made of the anatase crystalline titania aggregate having an average size of 8 mμ of the titanium oxide of Example 1 (Comparative Example 1) Also, the same tests as in Example 1 were carried out except that a water-dispersed silica sol (average particle size: 15 mμ, solid content 10%) (Comparative Example 2) was used. The results are shown in Table 1.

Comparative Example 3 The polycarbonate plate used in Example 1 was evaluated without coating. The results are shown in Table 1.

[Effects of the Invention] The coated transparent molded article obtained according to the present invention has the following effects.

(1) Excellent weather resistance. (Especially effective for preventing yellowing deterioration of a plastic substrate due to light.) (2) High surface hardness.

(3) It has excellent chemical resistance.

(4) It has excellent ultraviolet absorption.

Claims (4)

[Claims] 1. A transparent coated molded article, characterized in that a transparent plastic substrate is provided on its surface with a coating containing the following components A and B as main components. A. Organic matter-containing polymer B. Cubic shape in which L / D is 1 to 10 and L and D are 4 to 60 mμ, where L is the major axis length of the particle and D is the minor axis length. Alternatively, titanium oxide particles that are not rectangular parallelepiped aggregates. 2. The transparent coated molding according to claim 1, wherein the titanium oxide particles are anatase crystal particles. 3. The transparent coated molded article according to claim 1, wherein the organic substance-containing polymer is a thermosetting resin. 4. The transparent coated molding according to claim 3, wherein the thermosetting resin is a polymer obtained from an organosilicon compound represented by the following general formula (I). . RR ¹ _a SiX _3-a (I) (where R is an organic group having 1 to 10 carbon atoms, R ¹ is 1 to ¹ carbon atoms)
6 is a hydrocarbon group or a halogenated hydrocarbon group, X is a hydrolyzable group, and a is 0 or 1. )