JPH0453888B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for improving the surface properties of hydrophobic synthetic resins, particularly molded resins containing styrene units. Synthetic resins are used in a wide range of fields due to their excellent properties, but their molded products generally have no hydrophilic or ionic groups in the resin material itself, so they have poor water leakage, hygroscopicity, and dye receptivity. It has drawbacks such as poor elasticity and susceptibility to static electricity due to slight friction, which hinders its use in many fields. Conventional technology In order to solve these problems, conventional methods have generally been to apply water-absorbing substances, surfactants, antistatic agents, etc. to the surface of the molded product or to knead them into the resin. The coating agent may be removed by washing with water or wiping and lose its effectiveness in a short time, or in the latter case, the coating agent may bleed out onto the surface and deteriorate the quality of the molded product, or conversely, the coating agent may bleed out to the surface and degrade the quality of the molded product. It has the disadvantage that it cannot sufficiently modify the surface of the molded product if it remains in place. Modifying the surface of a resin molded product containing styrene units,
As a method to make the effect sustainable, for example, 1850 Å far ultraviolet rays generated from a low-pressure mercury lamp using a high-purity quartz glass tube are applied to a styrene-based resin.
A method of imparting hydrophilicity to molded products such as rubber-reinforced styrene resin and ABS resin by irradiating them (Special Publication Act 1973-
37227), a coating agent consisting of N-vinyl-2-pyrrolidone and alkyl (meth)acrylate is applied to the desired surface of the synthetic resin molded product, and the subsequent coating film is heat-treated or light-irradiated to prevent static electricity. A method (see Japanese Unexamined Patent Publication No. 109526/1983) has been proposed. The former method selectively oxidizes a resin containing styrene in its molecules using deep ultraviolet rays in the presence of air or oxygen, forming a highly hydrophilic composition on the surface and creating minute irregularities that cannot be observed with the naked eye. or by producing cracks, and the latter
Although it is not specifically targeted at resins containing styrene in its molecules, it is possible to coat the desired surface by applying the coating agent to the resin molding and then curing this coating film by heat treatment or irradiation with infrared rays, ultraviolet rays, etc. The purpose is to maintain the modification effect, and both require specific treatments such as heat and light irradiation. Summary of the Invention In the process of conducting various studies on various amphiphilic polymer solutes having aromatic rings in their side chains, the present inventors happened to discover certain amphiphiles having phenanthryl groups in their side chains. It was discovered that a polyelectrolyte strongly adsorbs to a polystyrene resin, a stable coating can be obtained, and the properties of the resin surface are improved, and as a result of further studies, the present invention was arrived at. That is, the present invention provides a hydrophobic synthesis method characterized in that a copolymer of an aromatic vinyl monomer and a vinyl monomer represented by the following general formula [] is attached to the surface of a hydrophobic synthetic resin molded product. The gist of this paper is a method for surface modification of resin molded products. General formula [] [However, R ₁ is H or CH ₃ , R ₂ is C number 2 to 4
alkylene group, and Y is H, Na, K or
NHR ₃ R ₄ R ₅ (R ₃ , R ₄ and R ₅ are H or C number 1
~4 alkyl group). ] Detailed Description of the Invention The hydrophobic synthetic resin moldings to be modified in the present invention are particularly styrene unit-containing resins such as polystyrene resins, acrylonitrile-styrene resins, styrene-butadiene resins, and ABS resins. In addition to these materials, acrylic resins such as methacrylic resins and polyester resins such as polyethylene terephthalate are also included. The shape of the molded product may be a film, sheet, plate, fiber, or any other shape. Examples of the aromatic vinyl monomer used in the present invention include styrene, vinylnaphthalene, vinylphenanthrene, vinylanthracene, vinylpyrene, etc., and the greater the number of condensed rings used, the more the resulting copolymer tend to have a strong adhesion to the above resins, and in this respect mention may be made of vinylnaphthalene, vinylphenanthrene, vinylanthracene and vinylpyrene, more preferably vinylphenanene, vinylanthracene and vinylpyrene. Specifically, 9-vinylphenanthrene, 9-vinylanthracene, 1-vinylpyrene, etc. are usually used. Typical vinyl monomers represented by the general formula [] include 2-acrylamido-2-methylpropanesulfonic acid and its Na, K,
NH ₄ , alkylamine salts, etc. The composition ratio of the copolymer of the above aromatic vinyl monomer and the vinyl monomer represented by the general formula [] is 10/90 to 80/20, preferably 30/70 to 70/
It is in the range of 30. These copolymers are normally soluble in organic polar solvents such as methanol, ethanol, dimethyl sulfoxide (DMSO), and dimethyl formamide (DMF), but they are soluble in water such as styrene, vinylnaphthalene, and vinylphenylene. When nanthrene and vinylpyrene are used, they usually become insoluble if their respective proportions in the copolymer exceed 75, 50, 50 and 30 mol%. Copolymerization is performed by adding monomers in a predetermined composition ratio to an organic polar solvent such as methanol, ethanol, DMSO, DMF, etc. so that the total concentration of the monomers is in the range of 5 to 50% by weight, preferably 10 to 30% by weight. Using common radical polymerization initiators such as azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), cumene hydroperoxide, etc.
Perform at a temperature of ~100℃. The obtained copolymer can be obtained in solid form by precipitating it from the polymer solution using an organic solvent such as hexane, acetone, or ether; It can be used for surface modification of molded products. In any case, in order to attach the copolymer to the resin molding, it is necessary to dissolve the copolymer in an organic polar solvent such as methanol, ethanol, DMSO, or DMF, and apply this to the surface of the resin molding. in,
As a result, a strong and stable coating is formed on the surface of the molded product, which does not come off even when washed with water. However, when the copolymer is applied as an aqueous solution,
A stable film as described above cannot be obtained. This is because hydrophobic domains of the aromatic side chains in the copolymer are formed in aqueous solution, and the ionic grapes surround the interface, which is thought to be involved in adhesion to the surface of the resin molding. This is presumably due to the fact that the group side chains cannot directly contact the surface of the molded product. The concentration of the copolymer in the organic polar solvent during coating is usually in the range of 0.5 to 10% by weight. A film can be easily formed on the surface. Removal of solvent
The adhesion of the film can be further increased by drying at a temperature of about 50° to 100°C or under vacuum. The thickness of the coating is not particularly limited as long as it can impart hydrophilic properties to the molded product, but usually
0.01μ or more is sufficient. The coating operation itself is not particularly limited,
Known methods such as brushing, spraying and dipping may be employed. Effects In the present invention, for example, a copolymer of an aromatic vinyl monomer and a vinyl monomer having a specific ionic group is dissolved in an organic polar solvent, and this is simply applied to a hydrophobic resin molded article. By simply removing the solvent, a strong and stable coating can be formed on the surface of the molded product, thereby imparting durable hydrophilicity, antistatic properties, etc. to the molded product. Example Production Example 1 After copolymerizing 9-vinylphenanthrene (VPh) and 2-acrylamido-2-methylpropanesulfonic acid triethylamine salt (AMPS/TEA) under the following conditions, this polymerization solution was Precipitate the copolymer by pouring into hexane with stirring,
Obtained. Solvent: Tetrahydrofuran (THF) Monomer composition: VPh/AMPS・TEA=32/68/
(Mole) Monomer concentration: 25% by weight Polymerization initiator: AIBN Polymerization initiator concentration: 0.1 mol% vs. monomer polymerization temperature: 60°C Polymerization time: 6 hours Example 1 Copolymer obtained according to Production Example 1 Prepare a 1.0% by weight methanol solution of
ml/cm ² (0.025 for expanded polystyrene)
ml/cm ² ), and the solvent was evaporated and removed at room temperature. The hydrophilicity of the resin test plate before and after applying the copolymer was
0.1 ml of distilled water was gently dropped onto each test plate, and the spread diameter (mm) was evaluated. Regarding the stability of the coating, water resistance was examined by immersing a test plate in water for a predetermined period of time. 【table】

Claims (1)

[Claims] 1. A hydrophobic product characterized by adhering a copolymer of an aromatic vinyl monomer and a vinyl monomer represented by the following general formula [] to the surface of a hydrophobic synthetic resin molded product. Surface modification method for synthetic resin molded products. General formula [] [However, R ₁ is H or CH ₃ , R ₂ is C number 2 to 4
alkylene group, and Y is H, Na, K or
NHR ₃ R ₄ R ₅ (R ₃ , R ₄ and R ₅ are H or C number 1
~4 alkyl group). 2. The surface modification method according to claim 1, wherein the aromatic vinyl monomer is vinylnaphthalene, vinylphenanthrene, vinylanthracene or vinylpyrene.