JPS6258301B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of adhering rubber and polyamide resin. In recent years, a wide variety of thermoplastic plastics have appeared, including engineering plastics (polyamide, polyester, polycarbonate, polyacetal, polysulfonate, polysilicon, polyphenylene oxide, polyimide,
ABS, methacrylic, etc.) resins are manufactured and sold, and many of these resins exhibit excellent mechanical strength, heat resistance, creep resistance, chemical resistance, electrical properties, dimensional stability, etc. over a wide range of areas. Under a wide range of usage conditions, they often replace metals such as iron, zinc, and aluminum. Usually, industrial rubber products include products such as rubber and metal, rubber and plastics, and rubber and solid materials, but most of them are composites consisting of rubber and metal. However, recently these products have become lighter, rust-proof,
Due to the requirements for chemical resistance, abrasion resistance, electrical properties, coefficient of friction, etc., there is a tendency to replace rubber and plastic composite products. Naturally, to create these composites, the bond between the rubber and plastic must be strong enough. The conventional method is to apply a chlorine-containing adhesive to the surface of a resin molded article obtained by injection molding, and then vulcanize and bond it to unvulcanized rubber. A disadvantage of the vulcanization bonding method for resin molded products and rubber is that the molded products are subjected to cooling/heating cycles or heat aging during the vulcanization bonding process, resulting in a decrease in adhesive strength or cracks in the solution molded product. Problems in the process, problems such as the adhesive strength differing significantly depending on the type of resin, etc.
Furthermore, when a thermoplastic resin having a low melting temperature is used, there is a problem that the molded article may be deformed by the temperature or pressure applied during vulcanization. In order to overcome the above problems, various researches have been conducted on a method in which, unlike conventional methods, the vulcanized rubber surface is treated to form a specific rubber surface area, and pre-molten polyamide resin is injected onto this area. The present invention was achieved by discovering a method of adhering vulcanized rubber and resin that can produce molded products with strong strength and high dimensional accuracy. That is, in the present invention, when bonding a polyamide resin to a vulcanized rubber surface, the vulcanized rubber surface is treated with a dilute solution of trichloroisocyanuric acid to form a specific rubber surface area, and the heated and melted polyamide resin is applied to this specific rubber surface area. The present invention relates to a method of bonding vulcanized rubber and polyamide resin, which is characterized by bonding the resin by injection or extrusion. According to the present invention, vulcanized rubber of any shape is prepared in advance, the surface to be bonded is treated with a dilute solution of trichloroisocyanuric acid, and then the mold is assembled into a mold, into which heated and molten polyamide resin is injected. Alternatively, by adhering by a method such as extrusion molding, it is possible to obtain a composite of rubber and plastics whose interfaces are firmly bonded. Furthermore, since the rubber article according to the present invention is treated with a solution or the like without mechanical treatment such as buffing with sandpaper or a grinder on the surface to be adhered, a composite having a precise and complicated shape can be obtained. be able to. Furthermore, since the concentration of the treatment liquid is low, deterioration of the treated rubber surface can be suppressed, making it possible to use the product for a long period of time as a product subject to vibrations, etc. The present invention will be explained in detail below. The rubber component of the vulcanized rubber used in the present invention is natural rubber (NR) and synthetic rubber having a carbon-carbon double bond in its structural formula, either alone or in a blend of two or more. The synthetic rubbers include polyisoprene rubber (IR), polybutadiene rubber (BR), and polychloroprene rubber, which are homopolymers of conjugated diene compounds such as isoprene, butadiene, and chloroprene;
Styrene-butadiene copolymer rubber (SBR), which is a copolymer with vinyl compounds such as acrylonitrile, vinylpyridine, acrylic acid, methacrylic acid, alkyl acrylates, and alkyl methacrylates, vinylpyridine-butadiene-styrene copolymer rubber, acrylonitrile-butadiene copolymer Copolymers of olefins such as ethylene, propylene, isobutylene and diene compounds, such as rubber, acrylic acid butadiene copolymer rubber, methacrylic acid butadiene copolymer rubber, methyl acrylate butadiene copolymer rubber, methyl methacrylate butadiene copolymer rubber, Examples include isobutylene isoprene copolymer rubber (IIR), copolymers of olefins and nonconjugated dienes (EPDM), ethylene, propylene, and cyclopentadiene ternary copolymers, and ethylene-propylene-5-ethylidene-2-norbornene ternary copolymers. Polymer, ethylene propylene-1,4-
Hexadiene terpolymer, polyalkenamer obtained by ring-opening polymerization of cycloolefin, such as polypentenamer, rubber obtained by ring-opening polymerization of oxirane ring, such as polyepichlorohydrin rubber, polypropylene oxide rubber, etc., which can be sulfur-vulcanized. is included. Also included are halogenated products of the various rubbers mentioned above, such as chlorinated isobutylene isoprene copolymer rubber (Cl-IIR) and brominated isobutylene isoprene copolymer rubber (Br-IIR). Furthermore, ring-opened polymers of norbornene can also be used.
Further, as a blended rubber, a saturated elastic material such as epichlorohydrin rubber, polypropylene oxide rubber, or chlorosulfonated polyethylene may be blended with the above-mentioned rubber. The vulcanized rubber of the present invention includes fillers such as carbon black, silica, calcium carbonate, calcium sulfate, clay, diatomaceous earth, and mica, softeners such as mineral oil, vegetable oil, and synthetic plasticizers, and stearin. Vulcanization accelerators such as acids, anti-aging agents, cross-linking agents, accelerators, etc. are thoroughly kneaded in advance using a kneader and vulcanized under appropriate vulcanization conditions. Vulcanized rubber can be produced by vulcanization with organic sulfur compounds, such as dithiodimorpholine, thiuram vulcanization, peroxide vulcanization, quinoid vulcanization, resin vulcanization, and metal vulcanization, in addition to the common and most important sulfur vulcanization. It includes all those obtained by salt vulcanization, metal oxide vulcanization, polyamide vulcanization, radiation vulcanization, hexamethylenetetramine vulcanization, and the like. During actual treatment, trichloroisocyanuric acid (TCCA) is dissolved in an appropriate solvent to a concentration of 0.1~
It is used at a concentration of 10% by weight, preferably 1-5% by weight. Specific examples of solvents include halogenated hydrocarbons such as carbon tetrachloride, chloroform, and dichloromethane, aromatic hydrocarbons such as benzene, nitrobenzene, halogenated benzene, toluene, and xylene, dimethyl ether, diethyl ether, tetrahydrofuran (THF), and dioxane. Chain or cyclic ethers such as, esters such as ethyl acetate, pentane, hexane, heptane, octane,
Examples include aliphatic hydrocarbons such as cyclohexane, ketones such as acetone, cyclohexanone, and methyl ethyl ketone, and alcohols such as ethanol, ethylene glycol, and tertiary butyl alcohol, among which are tetrahydrofuran, dioxane, acetone, benzene, and toluene. , carbon tetrachloride, chloroform, methyl ethyl ketone, and ethyl acetate are preferably used. The method of treating the rubber surface with the treatment agent to form a specific rubber surface area includes application with a brush,
Any industrial means capable of contacting the rubber surface with the treatment solution can be employed, such as spraying, dipping, etc. On the other hand, polyamide resins include nylon 6,
11, 12, 66, 610, their copolymers, blends, etc., and also those in which the functional groups of these polyamides have been partially modified. Furthermore, inorganic fillers such as glass fiber, calcium carbonate, and talc may be added to the above polyamide. It is also possible to mix polyester resin, polymethacrylic resin, polystyrene resin, polycarbonate resin, polyvinyl chloride resin, ABS resin, and other thermoplastic resins with the resin to improve processability, adhesion, etc. be. In order to adhere a polyamide resin to a specific rubber surface area of vulcanized rubber, the resin may be melted in advance, injected or extruded onto the specific rubber surface area, and then cooled to harden the resin. Next, the invention will be explained with reference to examples. Example 1 From a rubber composition with the formulation shown in Table 1,
ASTM: D429, Metnod B, for 90° peeling shown in b and ASTM D429 shown in Figure 2 a, b,
A vulcanized rubber was prepared to obtain a conical tensile test specimen of Method C (dimensions of the specimen in the drawings are in millimeters). On the other hand, pseudohalogen compounds are used as surface treatment solutions.
TCCA (trichloroisocyanuric acid) and DCTS (N,N-dichloro-p-toluenesulfonamide) as a comparative example were used at concentrations of 2, 5, 10, and 20, respectively.
A % by weight acetone solution was prepared and treated by brushing the surface of the part of the vulcanized rubber to be adhered. On the other hand, as polyamide resins, nylon 6 (CM-1001 manufactured by Toray Industries, Inc.), nylon 66 (CM-1001 manufactured by Toray Industries, Inc.),
3001N) and nylon 12 (Diamid manufactured by Daicel), each at a temperature of 120℃ and 5mmHg.
It was dried under the following conditions for 8 hours. Then, in the case of nylon 6 (230
℃), nylon 66 (250℃), and nylon 12 (180℃), incorporate the vulcanized rubber pieces shown above into the mold, inject each polyamide resin, and As shown in Fig. 2,
A composite test piece of rubber and plastic was prepared. After that, ASTM: D429 Method B and
Table 2 shows the results of an adhesion test conducted according to Method C. These results show that in the case of no treatment, the vulcanized rubber and polyamide resin do not adhere to each other, and in the test piece treated by the method of the present invention, both adhere strongly even in a dilute solution.

【table】

[Table] Example 2 From the rubber composition shown in Table 1 of Example 1
A vulcanized rubber was prepared to obtain a conical test piece of ASTM D429, Method C, and the same polyamide resin as in Example 1, nylon 6 (manufactured by Toray Industries, Inc., CM-1001), and nylon 6,6 were prepared. (manufactured by Toray Industries, Inc., CM-3001N) and nylon 12 (manufactured by Daicel Corporation, Diamid) were prepared. The surface of the vulcanized rubber was treated with the various treatment methods shown below for 15 seconds each, and then the various polyamide resins described above were injection molded at the same temperatures as shown in Example 1 to prepare composite test pieces. Thereafter, an adhesion test was conducted according to ASTMD429, Method C. The results are shown in Table 3. (Treatment method 1) Dissolve trichloroisocyanuric acid in acetone to make a 10% by weight solution, immerse a vulcanized rubber test piece in this solution for 15 seconds, and then dry it with hot air at 50°C for 30 seconds. (Treatment method 2) Concentrated sulfuric acid (concentration 96%, specific gravity 1.84) and concentrated nitric acid (concentration
70%, specific gravity 1.42) at a volume ratio of 200:100,
A vulcanized rubber test piece was immersed in this solution for 15 seconds, momentarily washed with running water, and then dried with warm air at 50°C for 30 seconds. (Treatment method 3) Leave the vulcanized rubber test piece in chlorine gas at room temperature for 15 seconds. (Treatment method 4) Mix water, sodium hypochlorite (chlorine content 10%), and hydrochloric acid (concentration 35%) at a volume ratio of 100:15:10, and immerse the test piece in this solution for 15 seconds. (After washing instantly with running water) It was dried with warm air at 50°C for 30 seconds. (Treatment method 5) Immerse the test piece in saturated bromine water for 15 seconds at room temperature,
(After washing instantly with running water) It was dried with warm air at 50°C for 30 seconds.

[Table] From Table 3, it is clear that the method of the present invention must be used in order to obtain sufficient adhesive strength even during short-time treatment.

[Brief explanation of the drawing]

Figures 1a and b are a plan view and a sectional view of a test piece for evaluating the bonding method of the present invention, Figure 2a is a
and b are a side view and a cross-sectional view of another test piece. 1...Polyamide resin, 2...Rubber.

Claims (1)

[Claims] 1. In adhering the polyamide resin to the vulcanized rubber surface, the vulcanized rubber surface is bonded by injection or extrusion with heated and molten polyamide resin to a specific rubber surface area that has been treated with a dilute solution of trichloroisocyanuric acid. A method for bonding vulcanized rubber and polyamide resin.