JPS6332092B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coated polycarbonate molded article having a coating containing a curable organopolysiloxane that is firmly adhered to a polycarbonate substrate and is transparent and has excellent scratch resistance. Polycarbonate resin has excellent transparency and moldability, and is used for various purposes, but it has been widely used as a substitute for glass products because of its excellent impact resistance and low specific gravity. Its advantages are particularly used in structures such as windows and windshields of various means of transportation such as automobiles, trains, and aircraft, display boards of various equipment, viewing windows, and lenses for eyeglasses such as safety glasses, corrective glasses, and sunglasses. It is being demonstrated. However, on the other hand, the surface hardness of polycarbonate resin,
The scratch resistance is quite low compared to, for example, methacrylic resin, which is another transparent material. In order to overcome this drawback, it has been proposed to coat the surface of polycarbonate resin with various coating materials. Among these, coating materials containing curable organopolysiloxanes have been proposed as particularly suitable. In particular, a composition suitable for polycarbonate is one in which a specific epoxy resin is blended with an epoxysilane hydrolyzate.
116731), but in general, the use of an undercoat is considered suitable for improving adhesion and expanding the selection range of organopolysiloxane surface coatings, and various undercoating materials have been proposed. ing. Among these are compositions consisting of epoxysilane and aminosilane (Japanese Patent Application Laid-open No. 54-63176), ultraviolet curable compositions containing polyfunctional acrylic esters (Japanese Patent Application Laid-open No. 55-148157), and compositions containing carboxyl or amino groups. Polymers with side chains (Unexamined Japanese Patent Publication No. 1983-
8258) and other technologies have been disclosed. Applying high temperatures to harden plastic coatings, especially polycarbonate resin coatings, is undesirable from the viewpoint of crazing and whitening caused by solvents, even if the resin does not deform, and is also undesirable from the viewpoint of energy conservation. Low-temperature cure coating materials are desired. Furthermore, when a curable organopolysiloxane coating that exhibits relatively large shrinkage upon curing is used as the surface layer, an undercoat material with low curability is not preferred. In these respects, the above-mentioned epoxysilane and aminosilane compositions are insufficient in terms of durable adhesion, and polymers with carboxyl groups or amino groups tend to cause cracks when surface coating is applied, and these are used, for example, in melamine resins. High temperature is also required when crosslinking with. On the other hand, in the case of an ultraviolet curable undercoat, it is preferable from the viewpoint of saving energy and lowering the temperature, but there are problems such as installation of equipment and limitations on applicable molding materials. As a result of intensive study of these problems, the present inventors were able to obtain a polycarbonate molded product having high hardness and excellent scratch resistance, and having a coating that firmly adheres to the substrate. That is, the present invention provides: (1) A basic nitrogen-containing acrylic monomer from 0.2 to
Acrylic copolymer () consisting of 30% by weight B ester of aliphatic monohydric alcohol of acrylic acid or methacrylic acid or a mixture thereof 50-99.8% by weight C 0-40% by weight of other copolymerizable monomers An undercoat layer obtained by applying a composition containing a compound or resin () having two or more epoxy groups per molecule, and (2) a curable organopolysiloxane coated on the undercoat layer. This is a coated polycarbonate molded product with excellent scratch resistance that is coated with a surface layer. The undercoat layer used in the present invention is already known (Japanese Unexamined Patent Publication No. 52-76338), and it is also described that it is a low-temperature curing material that has good performance for plastics. The present invention has discovered that an undercoat layer made of this composition has excellent properties in forming a curable organopolysiloxane-containing coating on a polycarbonate substrate. What is polycarbonate resin referred to here?

This is a general term for polymers containing a group represented by the following formula in its main chain, and the resin used in the present invention is particularly one having a structural unit represented by the following general formula. (In the formula, A and B are selected from the group consisting of phenylene, halogen-substituted phenylene, and alkyl-substituted phenylene, and R ¹ and R ² are respectively hydrogen,
It is selected from the group consisting of a saturated aliphatic hydrocarbon group or a group in which R ¹ , R ² and C form an alicyclic hydrocarbon group, and the total number of hydrocarbon groups in A and B is 12 or less. ) In particular, a polycarbonate resin having a structural unit represented by the following general formula obtained from the reaction of bisphenol A and phosgene is preferably used. (In the formula, n is 10 to 400) Component A of the acrylic copolymer () used as the undercoat used in the present invention is dimethylaminoethyl acrylate or methacrylate, diethylaminoethyl acrylate or methacrylate, t-butylamino Acrylic acid and/or methacrylic acid derivatives such as ethyl acrylate or methacrylate are preferably used, but other acrylamide or methacrylamide derivatives such as N-dimethylaminoethyl acrylamide, N-diethylaminoethyl acrylamide or methacrylamide can also be used. The amount used is 0.2 to 30% by weight, preferably 2 to 15% by weight. If it is too small, it is undesirable from the viewpoint of curability, and when it is too large, it is undesirable from the viewpoint of coloring. As component B of the acrylic copolymer (2), an ester of acrylic acid or methacrylic acid and a monovalent acyclic or cyclic aliphatic alcohol is used. Specifically, esters of acrylic acid or methacrylic acid with methanol, ethanol, propanol, butanol, lauryl alcohol, stearyl alcohol, etc., and mixtures thereof are used, and esters with methanol are particularly preferred. The amount used is 50-99.8% by weight, preferably 70-90% by weight. As component C of the acrylic copolymer (), a small amount of acrylic acid and/or methacrylic acid is preferably used, but in addition, styrene, α-methylstyrene, vinyltoluene, acrylonitrile, vinyl acetate, 2-hydroxyethyl or propyl Acrylate or methacrylate or acrylamide or methacrylamide and their (alkyl)methylol compounds, itaconic acid, glycidyl acrylate or methacrylate, 2-vinylpyridine, etc., which can be copolymerized with component A and component B, can all be used, and the amount used is 0-40% by weight, preferably 0.1-15% by weight. The above acrylic copolymer () can be polymerized by any polymerization method, but solution radical polymerization is preferred.
That is, aromatic solvents such as toluene, and/
Alternatively, it is a method of polymerizing by a conventional method using a polymerization initiator such as an azobis type and/or a peroxide type in the presence of an alcohol type solvent such as isobutanol and/or an ester type solvent such as ethyl acetate. It is also possible to use chain transfer agents such as mercaptans for the purpose of controlling the degree of polymerization. Preferably, the acrylic copolymer () is one in which component A, component B, and component C are copolymerized. It is also possible to polymerize component A, component B, and component C into two or more types, and then mix them, as in the case of some copolymers. As the compound or resin () having two or more epoxy groups per molecule used in the present invention, glycidyl ether of polyhydric alcohol is preferably used. That is, ethylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether, etc. are preferably used, but are not limited thereto. For example, acrylic resin copolymerized with glycidyl acrylate or methacrylate. system resin etc.1
Any substance containing a substance having two or more epoxy groups per molecule can be used. The blending ratio of the acrylic copolymer () and the epoxy compound or resin () is basic nitrogen atom (gram atom) in the acrylic copolymer ()/oxygen atom (in epoxy group) in the epoxy compound or resin (). Gram atom) is preferably about 0.5 to 5, but is not limited to this. As for the blending method, it is desirable to mix the acrylic copolymer () and the epoxy compound or resin () immediately before applying it to the object to be coated. That is, to a composition containing an acrylic copolymer () to which pigments, additives, solvents, etc. are added if necessary, a composition containing an epoxy compound or resin () to which a solvent and others are added, if necessary, is added and stirred, It is preferable to apply the coating to the object without leaving it for a long time, adding a solvent and other additives if necessary. The applied coating film is left at room temperature or, if necessary, heated to a relatively low temperature to form a cured coating film. The organopolysiloxane-containing coating forming the surface layer used in the present invention is obtained by curing a composition containing a silicon compound represented by the following general formula or a hydrolyzate thereof. (R ³ ) _a (R ⁴ ) _b Si(OR ⁵ ) _4-4(a+b) (where R ³ is an aliphatic hydrocarbon group with or without a substituent having 8 or less carbon atoms, R ⁴ has 6 carbons
All of the following hydrocarbon groups are bonded to a silicon atom through a Si--C bond, and R ⁵ is an alkyl, alkoxyalkyl, or acyl group having 8 or less carbon atoms. a and b are 0, 1 or 2, respectively, and a+b is 0, 1 or 2. ) However, the compound in which a+b is 1 or 2 accounts for 50% by weight of the silicon compound or its hydrolysis.
It is necessary to account for at least the following. Examples of these silicon compounds include tetraalkoxysilanes such as methyl silicate, ethyl silicate, n-propyl silicate, i-propyl silicate, n-butyl silicate, sec-butyl silicate and t-butyl silicate, methyltrimethoxysilane, Methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,
Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyl Triethoxysilane, γ-chloropropyltriacetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-(β- Glycidoxyethoxy)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β - Trialkoxy or triacyloxysilanes such as cyanoethyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, and dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, γ-glycidoxypropyl Methyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, γ-glycidoxypropylphenyldiethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyl Examples include dialkoxysilanes or diacyloxysilanes such as methyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, methylvinyldimethoxysilane, and methylvinyldiethoxysilane. be able to. These silicon compounds can be used as they are together with a curing catalyst, but in order to cure them at low temperatures, it is preferable to use a hydrolyzate obtained by reacting them with neutral or acidic water. These silicon compounds or hydrolysates are coated with other ingredients onto a polycarbonate substrate coated with an undercoat layer and cured. Other ingredients that form the surface layer coating include curing catalysts, fillers, and polymeric materials or prepolymers for performance modification. As the curing agent, all of the various curing agents known as catalysts for the silicon compounds mentioned above can be used. As the filler, colloidal silica is preferably used from the viewpoint of improving the surface hardness and maintaining transparency of the present invention. Furthermore, durability, flexibility, dyeability, antistatic properties, etc. can be improved by blending polyfunctional epoxy resins, melamine resins, and acrylic resins as polymeric materials or prepolymers preferable for performance modification. Other coloring agents such as dyes, leveling agents, antifoaming agents, antistatic agents, ultraviolet absorbers, etc. as necessary.
Various additives such as antioxidants and various solvents necessary for painting can be used. As a coating method for the undercoat layer or surface layer forming composition described below, a known method can be appropriately selected depending on the shape, size, etc. of the molded product. For example, brush painting, spray painting, dip painting, spin coating,
Roll painting, curtain flow painting, etc. can be applied. When curing, the undercoat layer and the surface layer can be cured separately, but after coating with the undercoat layer-forming composition, the coating film is allowed to dry to the touch by setting, and then the surface layer-forming composition is coated. , both layers can also be cured simultaneously. The curing temperature is preferably room temperature to 100°C for the undercoat layer, and 50°C to 130°C for the surface layer. Examples are shown below to clarify the effects of the present invention. Example 1 (1) Preparation of polycarbonate sheet coated with undercoat layer In a flask equipped with a cooler, thermometer, and stirrer, 50 g of toluene and isobutyl alcohol were added.
50g, diethylaminoethyl methacrylate 9
95°C.
The temperature rose to . The internal temperature was maintained at 95°C to 93°C and stirred. Add 0.5 azobiscyclohexanenitrile at the 4th, 6th, 8th, and 10th hours.
The polymerization was completed in a total of 12 hours to obtain a composition (A). Denacol EX to 100g of composition (A)
4 g of 617 (carbitol polyglycidyl ether manufactured by Nagase Sangyo Co., Ltd.) was added, stirred, and diluted with toluene/ethyl acetate = 1/2 thinner.
The diluted solution was spray-painted onto a polycarbonate sheet (Lexan 101 manufactured by Engineering Plastics Co., Ltd.) and dried at 70°C for 30 minutes to prepare a polycarbonate sheet coated with an undercoat layer. (2) Preparation of surface layer coating composition 202.2g of vinyltriethoxysilane and acetic acid
Put 15.2g into a beaker and stir with a magnetic stirrer while adding 57.3g of 0.05N hydrochloric acid aqueous solution to 20
Add dropwise at °C. After the dropwise addition was completed, stirring was continued for 30 minutes to obtain a vinyltriethoxysilane hydrolyzate. Similarly, 114.5 g of 0.01N hydrochloric acid aqueous solution was added dropwise to 289.8 g of methyltrimethoxysilane and 22.1 g of acetic acid to obtain a methyltrimethoxysilane hydrolyzate. The above vinyltriethoxysilane hydrolyzate and methyltrimethoxysilane hydrolyzate were mixed, 696.9g of the mixture was mixed with 62.0g of xylene,
A mixture of 15.5 g of butyl acetate and 1.2 g of a silicone surfactant was added and mixed with stirring. Further, 1.55 g of sodium acetate trihydrate was added and dissolved with stirring. (3) Manufacturing of polycarbonate molded products with high surface hardness (1)
The undercoat layer coated polycarbonate obtained in (2)
The coating was applied by dipping into the surface layer coating composition obtained in step 1 at a pulling speed of 10 cm/min. It was heat cured at 80°C for 2 hours. The following performance tests were conducted on the obtained polycarbonate sheet, and the results are shown in Table 1. (a) Steel wool with hardness #0000 under a load of 1.5 kg
It was rubbed 15 times (10 times) and the degree of damage was visually judged. (b) Falling sand test: Haze after dropping 1000 g of #80 carborundum according to ASTM D673-44.
was measured. (c) Adhesion: Curved tape test (d) Light resistance: 1 hour irradiation with ultra-high pressure mercury lamp (e) Accelerated weather resistance, measured by Sunshine Weather Meter (manufactured by Suga Test Instruments Co., Ltd.). It can be seen that the sheets obtained from these tests have extremely excellent scratch resistance, transparency, and durable adhesion. Example 2 (1) Preparation of surface layer coating composition 611.3 g of γ-glycidoxypropylmethyldiethoxydiethoxysilane and 0.05N aqueous hydrochloric acid solution
88.7 g was added dropwise and hydrolysis was carried out in the same manner as in Example 2. However, the liquid temperature during hydrolysis was maintained at 10°C. This γ-glycidoxypropylmethyldiethoxysilane hydrolyzate is combined with a bisphenol type epoxy resin (Epicote 827, manufactured by Ciel Chemical Co., Ltd.).
140g, propylene oxide modified bisphenol epoxy resin (Epicron 3002, manufactured by Kyoeisha Yushi Co., Ltd.) 140g, diacetone alcohol 330g
g, benzyl alcohol 165.2 g, acetylacetone 130 g and silicone surfactant 8.4 g.
g mixture was added and mixed with stirring. To this was added 2332 g of a methanol aqueous solution of colloidal silica (methanol silica sol, manufactured by Nissan Chemical Co., Ltd., solid content 30%), and an additional 69.6 g of acetylacetone aluminum was added.
g and stirred to dissolve. (2) Production of polycarbonate molded product with high surface hardness The polycarbonate sheet coated with the undercoat layer obtained in Example 1 was dip-coated in the surface coating composition obtained in (1) above at a pulling rate of 10 cm/min. After preliminary drying at 82°C for 12 minutes, it was heat-cured at 93°C for 4 hours. The thus obtained polycarbonate sheet with high surface hardness could be dyed with a disperse dye. The obtained polycarbonate sheet was subjected to the same performance test as in Example 1, and the results were summarized as
Shown in the table. It can be seen that it has extremely excellent scratch resistance, transparency, and durable adhesion. Comparative Example 1 Polycarbonate without any coating (Lexan manufactured by Engineering Plastics)
101), the same performance test as in Example 1 was conducted. Comparative Example 2 A performance test similar to that in Example 1 was conducted using a polycarbonate sheet coated with the surface layer coating composition used in Example 1 without an undercoat layer.

【table】

Claims (1)

[Claims] 1 A Basic nitrogen-containing acrylic monomer 0.2~
30% by weight B Acrylic acid or methacrylic acid aliphatic 1
Esters of alcohols or mixtures thereof
A composition in which a compound or resin () having two or more epoxy groups per molecule is blended with an acrylic polymer () consisting of 50-99.8% by weight C and 0-40% by weight of other copolymerizable monomers. 2. A coated polycarbonate molded article with excellent scratch resistance, which is coated with an undercoat layer obtained by coating the undercoat layer, and a surface layer containing a curable organopolysiloxane coated on the undercoat layer.