JPH0573763B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a synthetic resin molded article having a surface with excellent scratch resistance and antistatic properties. [Prior art] Currently, many synthetic resin molded products are on the market, and although they have many excellent properties, they generally have low surface hardness and low resistance to scratches, so they are difficult to handle during processing and transportation. The surface is easily scratched and scratched, which not only damages the product value, but also when removing dirt such as dirt that adheres to the surface of plastic products with a cloth during use. It is easily scratched, and it is also prone to abrasion scratches due to collisions with other objects, and in extreme cases, these scratches can cause the optical properties to be lost, making it completely unusable, a fatal drawback. It was hot. To address this problem, several methods have already been used industrially to form a scratch-resistant film on the surface of synthetic resin molded products, and the problem has been practically solved in many application fields. ing. However, in applications such as instrument dials and see-through panels, there is an extremely strong demand for synthetic resin molded products that not only have scratch resistance but also antistatic properties. However, with the prior art, a synthetic resin molded product having both scratch resistance and antistatic ability that satisfies market requirements has not been obtained industrially. That is, for example, in Japanese Patent Application Laid-open No. 55-86848,
A compound having three or more (meth)acryloyloxy groups (acryloyloxy group or methacryloyloxy group, hereinafter the same) in one molecule,
A coating that forms a film with both scratch resistance and antistatic properties by irradiating active energy rays in air, which is made of a polymerizable acidic phosphate ester having a (meth)acryloyloxy group and an ethanolamine compound. A material composition is disclosed. However, the above method has some problems, such as when a large amount of compound is added in order to impart sufficient antistatic ability, cloudiness tends to occur due to what is thought to have precipitated on the surface. There is a need for improvement. [Problems to be Solved by the Invention] Under the current situation as described above, as a result of intensive studies aimed at providing a synthetic resin molded product having sufficient scratch resistance and antistatic properties, we have found that a specific polymerizable product The above purpose can be achieved by forming a cured film on a synthetic resin molded product using a film-forming resin raw material consisting of a compound and a specific polymerizable acidic phosphate ester using a mold made of glass or metal. The present inventors have discovered that it is possible to obtain synthetic resin molded articles that meet the above requirements. [Means for Solving the Problems] The method for producing a synthetic resin molded article having a surface with excellent scratch resistance and antistatic properties according to the present invention is based on a method for producing a synthetic resin molded article having a surface with excellent scratch resistance and antistatic properties. 90 to 99.8% by weight of a polymerizable compound (A) having a group and the following general formula []

[Formula, R ₁ is hydrogen or a methyl group, R ₂ is hydrogen or

Formation of a film consisting of 0.2 to 10% by weight of a polymerizable acidic phosphate ester (B) represented by [Formula] group, R ₃ is hydrogen or a methyl group, and m and n are integers of 1 to 5. After coating the base resin raw material on the molding surface of a glass or metal mold or polymerizing and curing it sufficiently to the extent that it will not swell or dissolve with the injected base resin raw material to form a film in advance, the base resin raw material is applied. It is characterized in that it is injected and polymerized to transfer the above-mentioned pre-formed film to the base resin side. The most important feature of the present invention is that when providing a cured film with excellent scratch resistance and antistatic properties on the surface of a synthetic resin molded product, the above-mentioned specific mold and specific film-forming resin raw material are used in combination. There is a particular thing. Therefore, the synthetic resin molded product obtained by the present invention is
It has significantly better antistatic properties than synthetic resin molded products produced using similar film-forming resin raw material compositions in a gas such as air or in contact with a polymer film. For this reason, in the method of the present invention, the amount of polymerizable acidic phosphate ester added is small compared to other methods, and other defects in surface properties are less likely to occur. Specific examples of the mold used in the present invention include inorganic glass such as tempered glass, stainless steel, aluminum, and metal such as chrome plating. Glass and metal mold surfaces are generally mirror surfaces, but in some cases
A non-glare treatment with minute irregularities on the surface can also be used depending on the purpose. The polymerizable compound (A) having at least two acryloyloxy groups and/or methacryloyloxy groups in the molecule constituting the film-forming resin raw material of the present invention includes polyhydric alcohols and (meth)
Specific examples include esterified products obtained from acrylic acid or derivatives thereof, or esterified products obtained from polyhydric alcohol, polycarboxylic acid, and (meth)acrylic acid or derivatives thereof. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol having an average molecular weight of about 300 to about 1000, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,
3-butanediol, 2,3-butanediol,
1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol (2,2-dimethyl-1,3-propanediol), 2-ethyl-1,3-hexanediol, Dihydric alcohols such as 2,2'-thiodiethanol, 1,4-cyclohexanedimethanol, and other trimethylolpropane (1,1,1
-trimethylolpropane), pentaglycerol (1,1,1-trimethylolethane), glycerol, pentaerythritol (2,2-bishydroxymethyl-1,3-propanediol),
Diglycerol, dipentaglycerol, etc. Particularly preferred compounds obtained from these and (meth)acrylic acid include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaglycerol penta(meth)acrylate ) acrylate, dipentaglycerol hexa(meth)acrylate, etc. Additionally, polymerizable compounds obtained from polyhydric alcohols, polyhydric carboxylic acids, and (meth)acrylic acids or their derivatives are basically the hydroxyl groups of polyhydric alcohols, polyhydric carboxylic acids, and (meth)acrylic acids. It can be obtained by reacting a mixture such that both carboxyl groups are ultimately equivalent. Preferred compounds include esterified products obtained by using dihydric alcohol, trihydric alcohol, or a mixture of dihydric alcohol and trihydric alcohol as the polyhydric alcohol, and using a dihydric carboxylic acid as the polyhydric carboxylic acid. can be given. When using a mixture of trihydric alcohol and dihydric alcohol, the molar ratio of trihydric alcohol to dihydric alcohol can be arbitrarily selected. In addition, the molar ratio of divalent carboxylic acid and (meth)acrylic acid is as follows:
The equivalent ratio of acrylic acid to carboxyl group is 2:1
It is preferable that it is in the range of ~0:1. If the divalent carboxylic acid is in excess of the above range, the viscosity of the resulting ester becomes too high, making it difficult to form a coating film. Examples of divalent carboxylic acids include aliphatic dicarboxylic acids such as succinic acid, adipic acid, and sepacic acid; alicyclic dicarboxylic acids such as tetrahydrophthalic acid and 3,6-endomethylenetetrahydrophthalic acid; phthalic acid; isophthalic acid; Aromatic dicarboxylic acids such as terephthalic acid, thiodiglycolic acid,
Thiodivaleric acid, diglycolic acid or maleic acid, fumaric acid, itaconic acid, etc. or their chlorides, anhydrides and esters can be used. The general polymerizable acidic phosphoric acid ester (B) represented by [ ] constituting the film-forming resin raw material of the present invention includes (meth)acryloxyethyl phosphate and di(meth)acryloxyethyl phosphate. , (meth)acryloxypropyl phosphate, di(meth)acryloxypropyl phosphate, (meth)acryloxybutyl phosphate, di(meth)acryloxybutyl phosphate, and the like. Among these, (meth)acryloxyethyl phosphate, (meth)acryloxypropyl phosphate, and (meth)acryloxybutyl phosphate, which contain two OH groups in the molecule, are present in relatively small amounts. The addition of is particularly preferred since it exhibits excellent antistatic properties. In the present invention, the mixing ratio of the polymerizable compound (A) having at least two acryloyloxy groups and/or methacryloyloxy groups in the molecule and the polymerizable acidic phosphate ester (B) is
The amount of polymerizable acidic phosphate ester (B) is 0.2 to 10% by weight relative to 90 to 99.8% by weight of (A). If the amount of polymerizable acidic phosphate ester (B) added is less than 0.2% by weight, the antistatic properties of the resulting film surface will be insufficient, while if it exceeds 10% by weight,
Generally, the antistatic property is sufficient, but the surface tends to become cloudy due to being left unused, which is not preferable. The film-forming resin raw material of the present invention essentially consists of both the above compound (A) having at least two acryloyloxy groups and/or methacryloyloxy groups in the molecule and the polymerizable acidic phosphate ester (B). However, when carrying out the present invention, it is usually preferable to add a polymerization initiator, and in some cases, it is preferable to add a polymerization initiator. A compound having a function of promoting the development of preventive properties may be further added. In carrying out the present invention, polymerization and curing of the film-forming resin raw material is not particularly limited, but photopolymerization using ultraviolet irradiation is preferable because the equipment is relatively simple and productivity is high. . Therefore, as the polymerization initiator added to the film-forming resin raw material, a photosensitizer is preferable. Examples of such photosensitizers include, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetoin,
Examples include carbonyl compounds such as benzyl, benzophenone, and p-methoxybenzophenone, and sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide. These can also be used not alone but in combination of two or more. Further, sources of ultraviolet rays include mercury lamps, arc lamps, xenon lamps, and the like. The amount of these photosensitizers added is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the film-forming resin raw material. If the amount of photosensitizer added is too small, the polymerization and curing of the film will be slow, resulting in low productivity.On the other hand, if the amount added is too large, the weather resistance of the cured film will likely deteriorate. In addition, examples of compounds that promote the antistatic properties of the polymerizable acidic phosphate ester (B) mentioned above include (meth)acrylic acid, ethylene glycol mono(meth)acrylate, diethylene glycol mono(meth)acrylate, etc. , triethylene glycol mono(meth)acrylate,
Tetraethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylic acid ester with an average molecular weight of about 300 to about 1000, polyhydric alcohol mono(meth)acrylate such as glycerin mono(meth)acrylate, or N- Examples include ethanolamine compounds such as uralyl diethanolamine and N-stearyl diethanolamine.
Preferably, it is in the same amount as (B). Examples of other copolymerizable monomers that can be used in combination with the polymerizable compound (A) of the present invention include acrylic acid, methacrylic acid, esters thereof, acrylonitrile, methacrylonitrile, styrene, and derivatives thereof. can give. In addition, it is preferable for the viscosity of the film-forming resin raw material to be in the range of 1 to 1000 centipoise,
More preferably, it is 5 to 1000 centipoise. Further, the thickness of the film imparting scratch resistance and antistatic properties of the present invention is preferably in the range of 1 to 100 μm. When the film thickness is less than 1 μm, it is not preferable because, in some cases, sufficient scratch resistance may not be provided. On the other hand, the membrane pressure
When the thickness exceeds 100 μm, synthetic resin molded products with a film on the surface often become brittle. As the base resin raw material used in the present invention, methyl methacrylate or methyl methacrylate is used.
It is a mixture of polymerizable unsaturated monomers containing 80% by weight or more or a partial polymer thereof. Examples of polymerizable unsaturated monomers that can be copolymerized with methyl methacrylate include acrylic esters such as methyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate; methacrylic esters such as ethyl methacrylate; Examples include styrene and its derivatives. Examples of the polymerization initiator for the base resin raw material include azobisisobutyronitrile, azobisdimethylvaleronitrile, benzoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide, isopropyl peroxydicarbonate, and isobutyl. Free radical initiators such as peroxide, acetylcyclohexylsulfonyl peroxide can be used. It is also possible to use a redox polymerization initiator, such as a combination of peroxides and amines. Furthermore, various additives such as stabilizers, flame retardants, plasticizers, polymerization regulators, dyes, pigments, etc. may be added to the base resin raw material as necessary. In addition, as a release agent that facilitates the release of synthetic resin from the mold, the following general formula []

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Parts in the examples represent parts by weight. The scratch resistance is evaluated by the increase in haze value determined by the falling sand method shown below. In other words, the test piece is tilted at an angle of 45° to the horizontal direction and rotated around the vertical axis at a speed of 11 R.PM.
300g of 60 mesh carborundum from 70cm above
is dropped at a speed of 150 g/min, and the increase in haze value is calculated by subtracting the haze value before sand fall from the haze value after sand fall. Note that the haze value is expressed by the following formula. Haze value (%) = total light transmittance - parallel light transmittance / total light transmittance x 100 The smaller the increase in haze value, the better the scratch resistance. Moreover, the antistatic property was expressed by the value of charge half-life measured under the following conditions. That is, after holding the sample for 24 hours under constant temperature and humidity conditions at a temperature of 20° C. and a relative humidity of 50%, a voltage of 10 KV was applied for 10 seconds using an honest meter (manufactured by Shishido Shokai) to measure the half-life. In addition, changes in the appearance of synthetic resin molded products after being left unused will be observed after manufacture at a constant temperature and humidity of 20°C and relative humidity of 50%.
The results of observing the appearance after leaving the sample for a period of time are shown. Example 1 A film-forming resin raw material prepared by mixing 95 parts of 1,6-hexanediol diacrylate, 5 parts of Kayama-PM ₁ (monomethacryloxyethyl phosphate, manufactured by Nippon Kayaku Co., Ltd.), and 1.5 parts of benzoin ethyl ether was mixed with 1.5 parts of benzoin ethyl ether. 610mm×460mm×
Cast on one side of a 6mm (thick) tempered glass plate,
It is then covered with a polypropylene film cover with a thickness of 20 μm that is stretched on all sides, and the film is spread from above using a roller so that no air bubbles remain between the film and the glass plate until the thickness of the coating material is approximately 20 μm. I made it so. First, the item in such a state is 75
Irradiation was performed for 15 seconds from a height of 6 cm using 10 fluorescent chemical lamps (manufactured by Toshiba, FL-20BL) arranged at mm intervals. Thereafter, the cover film was peeled off from the pre-cured film, and the film was subsequently post-cured by irradiation for 30 seconds from a height of 20 cm using two high-pressure mercury lamps (manufactured by Toshiba, H2000L) arranged at 400 mm intervals. The thus treated glass plate was placed facing the untreated glass with the cured film on the inside to form a cell, and the cell was filled with 100 parts of methyl methacrylate partial polymer and 0.01 part of Tinupin P (ultraviolet absorber). Part 2, 2'-Azobisisobutyronitrile 0.05 part Nippon Kagaku Kogyo Co., Ltd., trade name "EAP" (mixture of monoethyl phosphate and diethyl phosphate) 0.05 part A resin raw material was injected. The periphery was sealed with a soft vinyl chloride gasket, the interval between the mold glasses was adjusted so that the resin plate was 3 mm, and polymerization was carried out by heating at 60°C for 6 hours and then at 120°C for 2 hours. After cooling, the scratch resistance of the surface on the non-coated side of the resin plate obtained by peeling it off from the glass plate shows that the haze value increases by 55% using the sand drop method, and the charge half-life is 120 seconds. As for the scratch resistance of the surface on which the film was formed, the haze value increased by 12% by the sand drop method, and the half-life of the charge was 1 second, and the scratch resistance and antistatic properties were improved. It was excellent, and no change in appearance was observed after standing. Comparative Example 1 The same film-forming resin raw material as in Example 1 was heated at 45°C.
It was cast onto one side of a 610 mm x 460 mm x 3 mm (thickness) methacrylic resin plate (Acrylite E, manufactured by Mitsubishi Rayon Co., Ltd.) heated to 100 mm, and then the polypropylene film under the cover and the cover film were cast in the same manner as in Example 1. The coating raw material coated in the absence of was polymerized and cured to obtain a resin plate with a coating similar to that of Example 1 on one side. The scratch resistance of the surface of the resin plate obtained in this way on which the film was formed was determined by an increase in haze value of 12% using the sand drop method.
and the charge half-life was 45 seconds. Comparative Example 2 The same film-forming resin raw material as in Example 1 was heated at 45°C.
It was cast onto one side of a 610 mm x 460 mm x 3 mm (thickness) methacrylic resin plate (Acrylite E, manufactured by Mitsubishi Rayon Co., Ltd.) heated to 400 mm in a nitrogen stream.
High-pressure mercury lamps (manufactured by Toshiba,
H2000L) from a height of 20 cm for 30 seconds on the side coated with the coating raw material to obtain a resin plate with a coating similar to that of Example 1 on one side. The scratch resistance of the surface of the resin plate obtained in this way on which the film was formed was determined by an increase in haze value of 12% using the sand drop method.
and the charge half-life was 53 seconds. Examples 2 to 4, Comparative Example 3 Resin plates were obtained by repeating the same operations as in Example 1, except that the film-forming resin raw materials were changed to those listed in Table 1. Table 1 shows the results of measuring the scratch resistance and charge half-life of the coated surface of the resin plate thus obtained, as well as the results of observing changes in appearance after standing. Comparative Examples 4 and 5 A resin plate on which a film was formed was obtained by repeating the same operation as in Comparative Example 1, except that the film-forming resin raw material was changed to those listed in Table 2. Table 2 shows the results of measuring the scratch resistance and half-life of the charge on the surface of the thus obtained resin plate on which the film was formed, as well as the results of observing changes in appearance after standing.

【table】

[Table] Example 5 The experiment was carried out using the continuous production apparatus shown in FIG. 1. In FIG. 1, belts 1 and 1' are mirror-polished endless stainless steel belts 1.5 m wide and 1 mm thick, the lower belt extending 12 m longer than the upper belt. The belt is made to run at a speed of 2 m/min by driving the main pulley 2', and the initial tension of the belt is given by providing a hydraulic cylinder on the tension pulley to 10 Kg/mm ² per belt cross section. It is set. Film-forming resin raw material consisting of 97.5 parts of trimethylolpropane triacrylate, 2.5 parts of "JPA-514" manufactured by Johoku Kagaku Kogyo (a mixture of monomethacryloxyethyl phosphate and dimethacryloxyethyl phosphate), and 5.0 parts of benzoin ethyl ether. 5 and 5' are coated on polyester films 7 and 7' with a thickness of 12 μm using roll coaters 6 and 6', and then coated on belts 1 and 1' with a thickness of 18 μm using press rolls 8 and 8'. Film-forming fat raw materials 5, 5' applied in this way
continues to use fluorescent chemical lamps (manufactured by Toshiba, FL
-40BL) After pre-curing with 12, 12', the polyester film is peeled off, followed by post-curing with high-pressure mercury lamps 13, 13'. The film-treated belts were placed facing each other, and both sides were sealed with polyvinyl chloride hollow pipes 15 containing a considerable amount of plasticizer.
Polymer content of 21%) 100 parts 2,2'-azobis(2,4-dimethylvaleronitrile) 0.05 parts Tinupin P 0.01 part Dai-ichi Kogyo Seiyaku Co., Ltd. Pricesurf A-217E (polyoxyethylene alkyl ether) A base resin raw material 14 consisting of 0.05 part of acidic phosphate ester is supplied through the injection device using a metering pump. The total length of the polymerization area is 96m, and the first 66m section consists of idle rollers 4 and 4′ arranged at 15cm intervals.
The distance between the belt surfaces is regulated in groups, and the distance is 80 mm from the belt outer surface.
℃ hot water is sprayed from a nozzle to heat the belt, and in the latter half of the 30m section, the belt is supported by idle rollers arranged at 1m intervals, and an infrared heater 1 is used.
7, it is heated to about 130°C and then cooled. After cooling, it was peeled off from the belt to continuously obtain a resin liquid with a thickness of 2 mm. The scratch resistance of the resin plate obtained in this way is that the haze value increases by 11% by the sand drop method, the charge half-life is 2 seconds, it has excellent scratch resistance and antistatic properties, and the appearance changes after being left. I couldn't see any.

[Brief explanation of the drawing]

FIG. 1 shows an example of a continuous manufacturing apparatus in which a cover having no affinity with the film is used to cure the film-forming resin raw material. 1, 1'... Endless belt, 2, 3, 2',
3'...Pulley, 4,4'...Idle roller, 5,5'...Film-forming resin raw material, 6,6'...
...Roll coater, 7,7'...Cover body, 8,
8'...Press roll, 9,9'...Nitspro roll, 10,10'...Cover body unwinding roller,
11, 11'...Cover body winding roller, 1
2, 12' 13, 13'... Curing device, 14... Base resin raw material, 15... Gasket, 16... Heater, 17... Infrared heater.

Claims (1)

[Scope of Claims] 1. 90 to 99.8% by weight of a polymerizable compound (A) having at least two acryloyloxy groups and/or methacryloyloxy groups in the molecule, and the following general formula: ₁ is hydrogen or a methyl group, R ₂ is hydrogen or a [Formula] group, R ₃ is hydrogen or a methyl group, and m and n are integers of 1 to 5. A film-forming resin raw material consisting of 0.2 to 1.0% by weight of acid ester (B) is applied to the molding surface of a glass or metal mold, and is sufficiently polymerized to the extent that it will not swell or dissolve by the base resin raw material that is injected later. After curing and forming a film on the surface of the mold in advance, a base resin raw material is injected and polymerized to transfer the previously formed film to the base resin side. A method for manufacturing a synthetic resin molded product having a surface with excellent preventive properties. 2. Excellent scratch resistance and antistatic properties as set forth in claim 1, wherein the polymerization and curing of the film-forming resin raw material is carried out by irradiation with ultraviolet rays in the presence of a photosensitizer. A method for manufacturing a synthetic resin molded product having a surface with a smooth surface. 3 The base resin raw material is methyl methacrylate or 80% by weight or more of methyl methacrylate and 20% by weight.
The composition having excellent scratch resistance and antistatic properties as described in claim 1, which is a mixture of the following unsaturated polymerizable monomer copolymerizable with this or a partial polymer thereof A method for manufacturing a synthetic resin molded product having a surface. 4. Scratch resistance and antistatic properties according to claim 1, characterized in that the molds are endless stainless steel belts that are mirror-polished on one side and move in the same direction and at the same speed. A method for manufacturing a synthetic resin molded product having an excellent surface.