JPH04339839A - Surface treatment of rubber product - Google Patents

Abstract

PURPOSE:To form, on a surface of the body of a rubber product, a film which is tack-free, has slip properties, and does not peel off during use, by applying a specific emulsion on the surface and drying the coating. CONSTITUTION:A microemulsion of a hydrosol of a water-soluble acrylic resin is applied on a surface of the body of a rubber product (e.g. rubber tube) to form a dry film.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for surface treatment of rubber products made of natural rubber and synthetic rubber including gene-based rubber;
More specifically, the present invention relates to a method for obtaining a rubber product that is non-adhesive and has slipperiness.

0002

[Prior Art] Conventionally, methods for treating the surface of rubber products made of synthetic rubber including natural rubber and gene-based rubber include (1) adding chlorine to the surface (chlorination);
) Surface degreasing by solvent treatment, (3) Surface oxidation by strong acid treatment, plasma treatment, corona treatment, etc., (4) Surface roughening by blasting, (5) Powder adhesion of silica, talc, and starch, (6) ) There was adhesion of resins such as silicone and fluororesin.

0003

[Problems to be solved by the invention] However, these methods are time-consuming and have many problems, such as deterioration of the working environment due to the use of harmful substances and strong oxidizing agents, and increased equipment costs due to the use of high energy. There was a problem.

Furthermore, with regard to chlorinated products, water marks may remain on the rubber product depending on the drying conditions after washing, and due to chlorination, the surface of the rubber may harden and cause micro-cracks. There was also a problem.

Regarding the adhesion of resin to the surface, the natural and synthetic rubbers that are the raw materials for these rubber products have few functional groups due to their composition, so resins can adhere to the surface, but the adhesion strength is low. It had the disadvantage of being weak

000
6] In addition, silicone oil and powder have the disadvantage that they are removed from the rubber surface after a short time of use, resulting in a sticky feeling, and other synthetic resins also have the disadvantage that the emulsion powder diameter is 0.
．． 05 to 0.2μ, so it sticks to the rubber product when it is standing still, but because the rubber surface is microscopically uneven, when the rubber product is stretched, it cracks and easily peels off in parts. , it was difficult to use it for a long time because it was removed.

[0007]

[Means for Solving the Problems] The present invention has been made in view of the above circumstances, and its means include applying an acrylic microemulsion of a hydrosol-type water-soluble resin to the surface of a rubber body, It is to provide a dry film.

[0008]

[Embodiments] To explain the embodiments of the present invention, the rubber body can be used for various rubber products made of natural rubber and synthetic rubber including gene-based rubber, which are well known in this technical field, such as rubber films, finger cots, etc. Nipples, dry suits, boots, automobile rubber frames, wiper blades, medical equipment (drayage bags, catheter balloons, urinary catheters,
condoms), tubes, packing rubber, rubber bands, gloves, etc., which are obtained by well-known manufacturing methods such as dipping and extrusion methods, and are coated with a hydrosol-type water-soluble resin on their outer or inner surfaces. The acrylic microemulsion is applied by any method such as coating, spraying, or dipping, and then dried to form a film on the surface.

The composition of the acrylic microemulsion of the hydrosol type water-soluble resin consists of a copolymer of a methacrylic acid ester monomer and an acrylic acid ester monomer, and the factors for selecting the monomer include hydrophilicity, Considering high reactivity, adhesion, and low coefficient of friction, monomers with good performance include methacrylic acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, and jetylaminoethyl. Methacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, methyl methacrylate, 2-
Monomers with particularly high performance include methacrylic acid, 2-hydroxyethyl methacrylate, and 2-ethylhexyl methacrylate. Moreover, it is possible to use these in combination with other monomers as the basic monomer of the copolymer.

[0010] Furthermore, in the present invention, it is necessary to adjust the solution concentration of this acrylic microemulsion to suit each rubber body, and a range of 0.1 to 20% is appropriate; A content of 0.5 to 10% is more effective.

[0011] The acrylic microemulsion of the hydrosol type water-soluble resin has a particle size of 0.05μ or less,
Due to the small particle size with a median particle size of 0.02μ or less,
The emulsion particles can sufficiently penetrate into microscopic irregularities on the surface of the rubber body.

In order to improve the solvent resistance, heat resistance, and water resistance of such emulsions, water-soluble melamine, epoxy resin, etc. are added as crosslinking agents, and organic amines or ammonium salts are added as catalysts. The rubber body is immersed in the surface treatment agent, or the surface treatment agent is applied to the surface by spraying or coating.

An example of the formulation of this surface treatment agent is as follows: 100 parts by weight of acrylic microemulsion (40%), 100 to 40,000 parts of water, 1 to 4 parts of water-soluble melamine, and 0.0 parts of organic amine catalyst. 1 to 0.4 parts. The amount of coating must be determined by taking into consideration the thickness of the film when it dries, but it should be formed as thin as possible so as not to change the texture of the rubber product.

Next, specific embodiments and comparative examples (conventional methods) will be described in detail. Example 1 and Comparative Example 1 Rubber tubes are formed by extruding the natural dry rubber formulations shown in Table 1 and processed according to the steps shown in Table 2. The blending example of the surface treatment agent in Example 1 was as follows: 300 parts of water, 2 parts of water-soluble melamine, and 0.2 parts of an organic amine catalyst were added to 100 parts by weight of an acrylic microemulsion (solid content 40%). It is.

Natural rubber 100 parts by weight S
2 parts by weight ZnO
3 Part by weight TET
1 Part by weight TMT
0.5 parts by weight stearic acid 1 part by weight anti-aging agent
1 part by weight

[0016]

[Table 1]

Example 2 and Comparative Example 2 Balloon catheters were formed using the natural rubber latex formulation shown in Table 3 by the dipping method, and processed according to the steps shown in Table 4. The surface treatment agent in Example 2 has the same formulation as in Example 1.

Natural rubber latex (DRY) 100 parts by weight S
1 part by weight ZnO
1
Part by weight dithiocarbamate vulcanization accelerator 0.8
Part by weight anti-aging agent
1 parts by weight stabilizer
Appropriate amount

[0019]

[Table 2] Next, films were prepared using the natural rubber latex formulation shown in Table 3, and Table 5 shows the physical properties and performance of the film treated with the surface treatment agent in Example 1 and the untreated film.

[0020]

[Table 3]

[0021]

[Effects of the Invention] In the present invention, an acrylic microemulsion of a hydrosol-type water-soluble resin is applied to the surface of the rubber body to form a dry film, which not only imparts non-adhesion and lubricity but also improves these properties. you get what you want,
Moreover, compared to conventional methods, it is extremely simple without requiring any pretreatment, and there is no peeling during use or during elongation.

[0022] That is, the hydrosol type water-soluble acrylic microemulsion has a particle size of 0.05μ or less,
The emulsion particles sufficiently penetrate and adhere to the microscopic irregularities on the rubber surface, forming a strong film that can be permanently formed on the surface of the rubber product, and since no powder is used, there is no contamination. without being removed during use.

Claims (1)

[Claims] 1. A method for surface treatment of rubber products, which comprises applying an acrylic microemulsion of a hydrosol-type water-soluble resin to the surface of a rubber body to form a dry film.