JPS5930170B2 - Method for manufacturing plastic molded products with wear-resistant coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides extremely high hardness on the surface of a plastic base material.
The present invention also relates to a method for manufacturing a wear-resistant plastic product having a crosslinked coating with good adhesion to a base material.

Plastic products made from polymethyl methacrylate, polystyrene, polycarbonate, polyallyl diglycol carbonate, cellulose acetate, cellulose acetate), unsaturated polyester cured products, polyvinyl chloride, etc. are lighter and more impact resistant than glass products. Because plastic products have various advantages such as being able to be manufactured quickly and being inexpensive, they are suitable for use in optical products such as organic plate glass, chandeliers, lighting equipment covers, optical lenses, In addition to display devices that use light sources, their use is being developed for use in signboards, ornaments, and other interior decoration products.

However, plastic products made from these plastics lack surface hardness, so the surface may be damaged by contact with other objects, collisions, or sticking, resulting in loss of aesthetic appearance. Optical properties deteriorate.

For this reason, plastic products are used for optical products, especially corrective eyeglasses,
Lenses for eyeglasses such as fashion glasses and sunglasses,
When used as optical lenses for cameras, microscopes, magnifying glasses, etc., protective masks for welding, gas masks, lenses for industrial materials used in aircraft window glass, etc., lenses for watches, etc., Scratches that occur on the product significantly reduce the value of the product. Various methods have been studied to improve the drawbacks of such plastic products, and the present inventors have also developed methods using triacryloyl compounds, trimethacryloyl compounds, tetraacryloyl compounds,
By using a cross-linked curable resin material mainly composed of tetramethacryloyl compound as a coating material, the wear resistance and surface hardness of the product are significantly improved compared to conventionally developed surface-hardened plastic molded products. Although a modified plastic molded article was successfully obtained, cracks were observed in some parts of the thus obtained molded article during use. The present inventors analyzed the cause of this problem and found that the main cause was insufficient adhesion of the cross-linked cured film, but this inconvenient phenomenon can also be eliminated by using a normal adhesion improver. I couldn't do it. In order to improve the adhesion between the plastic base material and the crosslinked cured resin coating having the specific composition, the present inventors have conducted various studies and found that the surface of the plastic base material is made of a resin material that can be crosslinked and cured by irradiation with active energy rays. When the plastic base material is coated and crosslinked and cured by irradiation with active energy rays, the plastic base material and the crosslinked cured resin coating are kept in a heated state at the time of irradiation with active energy rays. This cross-linked material significantly improves the adhesion of the resin film, does not cause cracks in the resin coating due to impacts, etc., and has extremely excellent robustness such as weather resistance, hot water resistance, scratch resistance, abrasion resistance, and surface strength. The present invention was completed by discovering that it is possible to form a cured resin film.

The present invention provides 200% polyol polyacrylate or polymethacrylate having three or more acryloyl groups or methacryloyl groups in one molecule on the surface of a plastic base material.
A plastic molded product with an uncrosslinked resin coating layer made of a resin material containing more than % by weight is crosslinked and cured by irradiating active energy rays while keeping it in a heated state.It has excellent wear resistance, surface hardness, and adhesion. A method for obtaining a plastic molded article having a crosslinked cured resin coating.

Plastic substrates used in the present invention include, for example, polymethyl methacrylate, copolymers of methyl methacrylate, methacrylic resins such as polycyclohexyl methacrylate, styrene resins such as polystyrene, AS resins, and ABS resins, polycarbonates, and polyallyl resins. Examples include various plastic molded products made from diglycol carbonate, hard vinyl chloride, cellulose resins such as cellulose acetate and cellulose acetate butyrate, unsaturated polyesters, and the like. Among these, base resins particularly suitable for carrying out the present invention include methacrylic resins, polycarbonates, polyallyl diglycol carbonates, styrene resins, etc., which have high transparency and aesthetic appearance. A major drawback of these plastic substrates is that they are severely lacking in damage resistance, but this drawback can be fully compensated for by application of the present invention.

The shape of the plastic molded product may be any shape depending on its purpose, use, etc., such as a plate shape, a distorted shape, a container shape, or other shapes.The molding method for these plastic molded products is resin. Various commonly used molding methods such as cast polymerization of raw material monomers or partial polymers thereof, injection molding, compression molding, extrusion molding, and blow molding can be arbitrarily selected.

The crosslinked curable resin material used in the present invention has a group in its molecule that can be crosslinked and hardened by irradiation with active energy rays, and in particular contains a compound having three or more acryloyl groups or methacryloyl groups in one molecule as an essential component. It is necessary to use

Examples of such crosslinked curable resin materials include the following. Examples include reaction products of acrylic acid, methacrylic acid, or halides thereof and trivalent or tetravalent alcohols such as trimethylolpropane, glycerin, trimethylolethane, pentaerythritol, and diglycerin.

These compounds need to be contained in the crosslinked curable resin material used in carrying out the present invention in a proportion of at least 20% by weight or more, preferably 30% by weight or more. A cured film made from a crosslinked curable resin material containing less than 20% by weight of the above compound cannot have excellent wear resistance and hardness.

1 in 1 molecule that can be used in combination with the above compounds.
Examples of compounds having one or two polymerizable unsaturated groups are as follows.

A compound having two polymerizable unsaturated groups in one molecule has an unsaturated group selected from an allyl group, an acryloyl group, or a methacryloyl group, and its main chain structure has an unsaturated carbonization other than an aromatic nucleus. Preferably, it does not contain structures such as hydrogen structures, hydroxyl groups, and carboxyl groups.

Compounds that have an unsaturated hydrocarbon structure in their main chain structure may become colored by irradiation with active energy rays, or the unsaturated hydrocarbon groups may remain without being sufficiently crosslinked, resulting in poor weather resistance of the crosslinked cured product of the compound. do. In addition, compounds having hydroxyl groups or carboxyl groups increase their viscosity, which reduces the coating workability of crosslinked curable resin materials containing the compounds, and also reduces the water resistance, weather resistance, and other properties of coatings formed by crosslinking and curing these materials. This is not preferable because it causes a decrease in The weight average molecular weight of the compound is preferably in the range of 150 to 450. Cured films made from crosslinked curable resin materials containing those having a molecular weight smaller than 150 may lack flexibility and impact resistance. This is not desirable because it also reduces sex. On the other hand, a cured coating made from a crosslinked curable resin material containing a large molecular weight of over 450 is not preferable because the hardness and abrasion resistance decrease. Specific examples of these compounds include ethylene glycol, propylene glycol,
Diacrylates or dimethacrylates such as butylene glycol, pentanediol, hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol hexaethylene glycol, dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid , diesters of terephthalic acid, irifthalic acid, phthalic acid, etc. and hydroxyalkyl acrylate or methacrylate, allyl diglycol carbonate, and the like.

Further, the monovinyl compound that can be used as a component of the crosslinked curable resin material used in the present invention preferably has a homopolymer glass transition temperature of 0°C or higher, preferably 30°C or higher. When using a monomer with a glass transition temperature lower than 0°C, the hardness of the resulting cured film decreases and it becomes impossible to form a film with good stain resistance and dust adhesion resistance. It's not right. Specific examples of these monomers include methyl acrylate, butyl methacrylate, stearyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, cyclohexyl acrylate, propyl methacrylate, hexadecyl acrylate, 2-butyl methacrylate, glycidyl methacrylate, and t-butyl acrylate. , isobutyl methacrylate, ethyl methacrylate, dimethylaminoethyl methacrylate, 2-
Hydroxyethyl methacrylate, isopropyl methacrylate, methyl methacrylate, phenyl methacrylate, styrene, cyclohexyl methacrylate and the like can be mentioned. When a film made from such a cross-linked curable resin material is irradiated with light and cross-linked and cured, disadvantageous phenomena such as coloring of the film and deterioration of optical properties occur compared to when other resin materials are used. However, on the other hand, the volume shrinkage phenomenon due to crosslinking of the film occurs more strongly than when other crosslinked curable resin materials are used, so the adhesion of the crosslinked film formed on the surface of the plastic substrate may be affected. However, according to the method of the present invention, it is possible to produce plastic molded products having coatings with excellent adhesion and good abrasion resistance. Furthermore, in carrying out the present invention, when using a crosslinked curable resin material containing 20% by weight or more of a compound having three or more acryloyl groups or methacryloyl groups in one molecule, crosslinking and curing formed on the surface of the plastic molded product. To further improve the adhesion of the film to the substrate and the optical properties, nonionic fluorosurfactants such as fluorocarbon sulfonamide, fluorocarbon aminosulfonamide, fluorocarbon carboxysulfonamide, fluorocarbon carboxysulfonamide, and fluorocarbon sulfonamide are used. Ethylene oxide adducts, fluorocarbon hydroxysulfonamide sulfate esters, fluorocarbon amino acid amides, fluorocarbon acid amides, ethylene oxide adducts of fluorocarbon acid amides, fluorohydrocarbon alkyl esters, etc., or fluorine-containing unsaturated monomers, e.g. 2.2.
3,3-tetrafluoropropyl (meth)acrylate,
2,2,3,3,4,4,5,5-octafluoropentyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 1,1,1,3,3,3- Hexafluoropropyl (meth)acrylate, 2, 2, 3
・4,4,4-hexafluorobutyl (meth)acrylate, 1,1-dihydroperfluoropropyl (meth)acrylate, 1,1-dihydroperfluorobutyl (meth)
Acrylate, 1,1-dihydroperfluoropentyl (
meth)acrylate, 1,1-dihydroperfluorohexyl (meth)acrylate, perfluoroethoxy-1,
1-dihydroperfluoropropyl (meth)acrylate, perfluoropropoxy-1,1-dihydroperfluoropropyl (meth)acrylate, perfluorobutoxy-1,1-dihydroperfluoropropyl (meth)acrylate, α-fluoroacrylic acid , α-difluoromethylacrylamide, α-trifluoromethylacrylamide, C
It is preferable to use Cl3CF2CF2CH=CH2 in combination.

The nonionic fluorine surfactant is added to the specific crosslinked curable resin material at a rate of 0.01 to 5% by weight, and in the case of a fluorine-containing vinyl monomer, it is added at a rate of 0.01 to 30% by weight. is desirable.

To carry out the present invention, the above-mentioned cross-linked curable resin material is applied after or while heat-treating a plastic base material, or the above-mentioned cross-linked curable resin material is applied to a plastic base material and then heat-treated. However, these materials may be irradiated with light while being heated if necessary.

Examples of methods for applying the crosslinkable resin material to the plastic substrate include brush coating, spin coating, spray coating, flow coating, dip coating, roll coating, grapier coating, bar coding, screen coating, air knife coating, and other methods. used. The film thickness of the crosslinked curable resin material can be arbitrarily selected depending on the purpose of use of the resulting product, but it is generally 0.01 to 50μ, preferably from 0.01 to 50μ, based on considerations such as surface hardness, impact resistance, and optical properties. 0.1-3
It is desirable to apply the coating to a thickness of 0μ. The film of the crosslinked curable resin material formed on the surface of the plastic substrate as described above is crosslinked and cured by irradiation with active energy rays. In the present invention, it is necessary that the liquid be kept in a heated state.

If the plastic substrate is not kept in a heated state, the adhesion between the crosslinked cured resin coating and the plastic substrate cannot be improved, and the plastic product often cracks during use, which is undesirable. Keeping the plastic base material in a heated state means warming the plastic base material from before applying the crosslinked cured resin material until the end of irradiation with active energy rays. It is necessary to be heated. Specific methods include a method of applying a heated cross-linked curable resin material to a plastic substrate at room temperature or a heated plastic substrate, a method of applying the resin material at room temperature to a heated plastic, or a method of applying the resin material at room temperature to a heated plastic. A method may be used in which the resin material is applied and then heated. It is preferable to keep the plastic base material at a temperature of 40°C or higher, especially in the range of 50 to 160°C.The optimum temperature range varies depending on the base resin. For diglycol carbonate and other polycarbonate resins, the temperature is preferably in the range of 70 to 160°C, and the heating time can be arbitrarily selected within a range that does not deform the base resin, but is generally within 60 minutes, preferably 1 to 20 minutes. It is. Any heating method can be used such as hot air, infrared rays or far infrared rays, or microwave oven, but heating with infrared rays or far infrared rays is particularly convenient, and the cross-linked hardening applied to the surface of the plastic substrate and the surface soil. This method is preferable because the resin material can be effectively heated and the adhesion between the crosslinked cured resin coating and the plastic substrate can be improved without deforming the substrate.

The active energy rays used in carrying out the present invention include, for example, wavelengths of 2000 to 8000λ, particularly 3000λ.
A light beam of ~4000λ, a γ line, etc. are used.

When using light rays as active energy rays, for example, ultraviolet rays emitted from xenon lamps, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, etc. can be used. is preferable. When irradiating with active energy rays, an appropriate atmosphere can be selected as necessary. For example, an active gas atmosphere such as oxygen or a mixed gas containing oxygen, or an inert gas atmosphere such as nitrogen gas, carbon dioxide gas, argon gas, helium gas, or krypton gas is used. When using light as the active energy ray, it is preferable to add a sensitizer to the crosslinked curable resin material, and the sensitizer collides with the crosslinked curable resin material to impart excitation energy to the resin material. and has the effect of accelerating the rate of photopolymerization and curing, or those that absorb light and decompose to generate radicals, which act as initiators for photopolymerization and curing of the resin material. is used.

Examples of these sensitizers include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin butyl ether, butyroin, acetoin, benzyl, benzophenone, azobis-2,4-dimethylvaleronitrile, and the like. The amount is preferably in the range up to 10% by weight, especially in the range from 0.1 to 5% by weight, based on the crosslinked curable resin material. The crosslinked cured film formed by the method of the present invention has surface strength,
It has excellent robustness such as abrasion resistance, scratch resistance, and impact resistance, and there is no peeling phenomenon of the film from the plastic base material even at high temperatures and high humidity, and it has excellent crack resistance, impact resistance, etc. even at high temperatures. Are better. Plastic products on which a crosslinked cured resin film is formed by the method of the present invention include, for example, corrective eyeglasses, fashion glasses, sunglasses, optical lenses such as cameras, microscopes, and magnifying glasses, protective masks for welding, gas masks, and aircraft window glasses. Plastics for industrial materials used in
In addition to watch lenses, organic plate glass, building materials such as lighting light covers, display materials, decorative items, containers,
Extremely useful for various dials, etc. Parts in the following Examples and Comparative Examples mean parts by weight.

Example 1 A monomer composition consisting of 40 parts of penta±lythritol tetraacrylate, 30 parts of trimethylolpropane triacrylate, and 30 parts of ethylene glycol diacrylate was added to a methacrylic resin plate with a thickness of 3 mm, and 2 parts of benzoinpropyl ether as a photosensitizer. The liquid composition containing the above was applied to a thickness of about 10 μm by spin coating at room temperature.

After coating, a 500 W infrared lamp was irradiated for 2 minutes from a distance of 25 cTrL in a nitrogen stream, and the surface temperature of the methacrylic resin reached 90°C. Furthermore, while continuing irradiation with an infrared lamp, UV rays were irradiated for 2 minutes from a distance of 20 CTIL using a 200W high-pressure mercury lamp for crosslinking and curing.

Although the surface temperature of the methacrylic resin plate reached 120° C., no deformation was observed, and a crosslinked cured resin film with an extremely high pencil hardness of 8H or more was formed on the resin. Adhesion test of the thus formed cured film using adhesive tape (cross-linked cured resin film formed on a plastic base material has grooves of 1m77 deep reaching the plastic base material)
! Make 100 Xlmm base stitches with a knife, stick adhesive tape on them, and then peel off the adhesive tape)
When the adhesive tape was peeled off 20 times, the cured resin film did not peel off at all.
No change in adhesion was observed even after 10 hours in warm water at 30°C and 2 weeks in a constant temperature room at 30°C and 95% relative humidity, proving that it had excellent adhesion.

For comparison, a sample in which the liquid composition was applied without irradiation with an infrared lamp and then immediately irradiated with ultraviolet rays without heating the plastic substrate was 55 pieces in one adhesive tape peeling test. It peeled off, and it all came off after 2 tries.

Example 2 40 parts of pentaerythritol tetraacrylate, 30 parts of glycerin triacrylate, 15 parts of allyl diglycol carbonate, 1.
3-Butylene glycol diacrylate. After spin-coating a liquid composition consisting of 15 parts of benzoin isobutyl ether and 2 parts of benzoin isobutyl ether to 8μ, a 500W infrared lamp was applied to the top 20μ of the sample. When irradiated for 5 minutes from a distance of , the surface temperature of the lens reached 125°C.

Thereafter, in a carbon dioxide gas flow, an infrared lamp was irradiated for another 2 minutes, and at the same time a high-pressure mercury lamp was irradiated for 2 minutes to form a cured resin film. The cured resin film thus formed was not scratched even when strongly rubbed with #000 steel wool, and no peeling was observed even after repeating the adhesive tape peeling test five times.

For comparison, a sample that was cured without irradiation with an infrared lamp had sufficient surface hardness, but most of the cured film was peeled off after one use of the adhesive tape.

Example 3 After drying methacrylic resin for injection molding (Acrypet VH manufactured by Mitsubishi Rayon) at 80°C for 5 hours,
Using an injection molding machine (manufactured by Japan Steel Works, Nikko Ankelberg V-14) equipped with a 4-cavity lens mold with a thickness of 2 m1, the cylinder temperature was 250°C, the mold temperature was 60°C, and the injection time was 0.8 seconds. Injection molding was performed with a holding pressure of 3 seconds, a cooling time of 62 seconds, and an intermediate time of 10 seconds.

30 parts of trimethylolethane triacrylate, 30 parts of 1,4-butylene glycol diacrylate, 4 parts of tetrahydrofurfuryl methacrylate on the surface of this lens.
0 parts, benzoin isopropyl ether, 2 parts, and silicone oil (XB2724 etc.) 0.1 parts for 30 seconds at 35°C, and then placed in a quartz box with a nitrogen stream at 70°C for 3 minutes. When the surface temperature of the resin plate reached 70° C., it was irradiated with a 100 W high pressure mercury lamp for 5 minutes. The cured resin coating has a thickness of 9μ, and
It exhibited a pencil hardness of H, and no peeling occurred even after peeling the adhesive tape 10 times. For comparison, a sample in which the same liquid composition was dip-coated at room temperature and then similarly irradiated with only a high-pressure mercury lamp without heating had most of the cured film peeled off in one adhesive tape peel test.

Example 4 A methyl methacrylate monomer containing 2% ethylene glycol dimethacrylate was cast polymerized to form two diagonal plates.

This resin plate was mixed with 40 parts of pentaerythritol tetraacrylate, 10 parts of triazine triacrylate, 1.3-
Butyre Z was immersed in a liquid composition consisting of 20 parts of glycol diacrylate, 30 parts of methyl methacrylate, and 3 parts of acetoin at 50°C, and then irradiated with an infrared lamp for 2 minutes in a carbon dioxide gas flow. The surface temperature of the resin was 87. ℃ reached. Further, while continuing the irradiation with the infrared lamp, the resin plate was irradiated with a high-pressure mercury lamp for 5 minutes to obtain a resin plate having a crosslinked cured resin film (the surface temperature of the resin was 120° C.).

The pencil hardness of this coating was 8H, and the adhesion to the base resin was good.

Example 5 The Acrypet lens used in Example 3 was prepared from 10 parts of pentaerythritol tetraacrylate, 25 parts of trimethylolpropane triacrylate, 15 parts of 1,4-butanediol diacrylate, 50 parts of methyl methacrylate, and 2 parts of benzoin isobutyl ether. After being immersed in the liquid composition at 35° C. for 1 second, it was left standing for 3 minutes in a quartz box with a nitrogen stream passed through it.

After 3 minutes of standing, both sides of the lens are 20CT! Ultraviolet rays were emitted from a high-pressure mercury lamp (100 W, manufactured by Ushio Inc.) from a distance of 1 (the intensity was reduced using an appropriate filter).

The strength on the base material surface was 0.3 W/7rI (365 mμ). ) was irradiated for 1 minute. 20 CT on both sides of the lens immediately after 1 minute of irradiation! Infrared lamp (250W) from distance L
) was irradiated for 1 minute.

The temperature of the substrate surface rose to 70-75°C. After 1 minute of infrared irradiation, strong ultraviolet rays are irradiated on both sides from a distance of 20 CWL.
The curing was completed by irradiation for a minute. Cured resin film is 8-10
It had a thickness of μ, a pencil hardness of 8H or more, and no peeling occurred even after the adhesive tape was peeled off 10 times. Further, no peeling occurred in a peel test after five thermal cycles (immersion in hot water at 65° C. for 1 hour → ice water for 10 minutes → dry heat at 80° C. for 1 hour). Example 6 A film crosslinked and cured in the same manner as in Example 1 except that the fluorine-containing compounds shown in Table 1 were added to 100 parts by weight of the liquid composition used in Example 1. A methacrylic resin plate having the following properties was created.

Claims (1)

[Scope of Claims] 1. Polyol having three or more acryloyl groups or methacryloyl groups in one molecule A plastic molded product having an uncrosslinked resin coating layer made of a resin material containing 20% by weight or more of polymethacrylate or polyacrylate. A method for manufacturing a plastic molded product having a wear-resistant coating, which comprises irradiating the uncrosslinked resin coating with active energy rays while maintaining the temperature to crosslink and harden the uncrosslinked resin coating. 2. The wear-resistant coating according to claim 1, wherein the plastic molded product is heated so that the surface temperature of the plastic molded product during irradiation with active energy rays is in the range of 50 to 160°C. A method for manufacturing a plastic molded product having 3. The plastic molded product is made of methacrylic resin, and has a wear-resistant coating according to claim 1, characterized in that the surface temperature of the plastic molded product when irradiated with active energy rays is 50 to 130°C. Method of manufacturing plastic molded products. 4. Claim No. 4, wherein the plastic molded product is a polyallyl diglycol carbonate resin molded product or a polycarbonate resin molded product, and the surface temperature of the plastic molded product when irradiated with active energy rays is 70 to 160°C. A method for producing a plastic molded product having a wear-resistant coating according to item 1. 5. Claims 1 and 2, characterized in that a cross-linked curable resin material containing a modifier selected from a nonionic fluorosurfactant and a fluorine-containing vinyl monomer is used as the cross-linked curable resin material. , the method for producing a plastic molded product according to item 3 or 4.