JPS6234797B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention requires that 10 to 80 parts by weight of zinc white, 5 to 40 parts by weight of acrylic acid and/or methacrylic acid, and an organic peroxide be contained per 100 parts by weight of olefinic synthetic rubber. The present invention relates to a film-like vulcanized rubber adhesive formed by molding a blended rubber composition into a film. The present invention has applications as a vulcanization adhesive between metals, between vulcanized rubber or unvulcanized rubber and metals, between vulcanized rubber or unvulcanized rubber, between vulcanized rubber and unvulcanized rubber, and for adherends. As a protective agent, for example, by placing a film that has no adhesive ability such as cellophane film on one side, the surface can be protected by peeling off the cellophane film after vulcanization and adhesion to rubber or metal surfaces. It can also be used as a coating. In this way, the film-like vulcanized rubber adhesive of the present invention is sandwiched between adherends, and the air between the film-like vulcanized rubber adhesive of the present invention and the adherend is expelled using a press molding machine, etc. By applying heat and temperature, the vulcanization of the rubber adhesive can be completed in a short time and a strong adhesive state can be obtained. More specifically, the film-form vulcanized rubber adhesive of the present invention is sandwiched between adherends, and pressure is applied in a state where no air exists between the adherend and the film of the present invention, and the temperature is increased to a temperature higher than the decomposition temperature of the organic peroxide. Good adhesion can be obtained by heating for several minutes. Conventionally, there has been no film-like vulcanized rubber adhesive as mentioned above; past examples include methods using adhesive-impregnated paper for making plywood, heat-melting methods for food packaging, and felt-like methods for bonding honeycomb cores. There were methods such as impregnating thread with adhesive and heat-pressing it, impregnating thread with adhesive and sandwiching it between fabrics and using a sewing machine, and sandwiching double-sided adhesive tape and pressure-bonding it. The film-like vulcanized rubber adhesive of the present invention is completely unprecedented. Conventionally, epoxy resin adhesives, cyanoacrylate adhesives, etc. have been used to bond metals together, but these adhesive layers lack rubber elasticity, so they cannot be bonded due to vibrations, shocks, or temperature changes. It was susceptible to adhesive fatigue such as distortion due to the difference in linear expansion coefficient between the adhesive layer and the adherend, and had shortcomings in durability. In addition, rubber-metal vulcanization adhesives have traditionally been used to bond rubber and metal, such as rubber rolls, rubber linings, electric wire coatings, valves, hoses, belts, anti-vibration rubber, oil seals, etc. As an adhesive, a method of using a coglue containing an elastomer to be bonded has been used for a long time. This method uses a highly hard composition containing a large amount of metal oxide as a primer formulation on the metal side, and an elastic composition with a high rubber content as a stock formulation on the rubber side, resulting in a final bonded product with excellent vibration resistance. Although it has the feature of being able to provide impact resistance, it requires many types of adhesives, which causes troublesome processes. Also, general-purpose two-component adhesives are well known, in which a metal primer is applied and dried on the metal surface of the adherend, then a top coat adhesive is applied and dried, and unvulcanized rubber fabric etc. are simultaneously vulcanized and bonded. It is being Although this adhesive is capable of simultaneously vulcanizing and adhering most unvulcanized rubber fabrics and metals, there are problems in simultaneously vulcanizing and adhering olefin-based synthetic rubber and metals, and a special adhesive is required. Furthermore, since the primer and adhesive must be applied and dried twice, there are disadvantages such as increased man-hours and economical waste. In addition, one-component adhesives containing isocyanate compounds etc. in a phenol resin solution have excellent heat resistance and oil resistance, and have excellent adhesion to general-purpose synthetic rubbers and natural rubbers, etc.; Due to the problem in its properties, it has disadvantages such as peeling at cut edges and bent parts during product processing. Adhesives for vulcanized rubber include polar rubbers such as chloroprene rubber, acrylonitrile-butadiene rubber, and polyacrylic acid resins, but they have poor heat resistance and are even more difficult to bond with olefin-based synthetic rubbers and olefin-based synthetic rubbers. It also has problems, such as the difficulty of adhering it to metal. The present invention eliminates the above drawbacks and has the following advantages. That is, the advantages of the film-like vulcanized rubber adhesive of the present invention are as follows. Since it is in the form of a film, there is no need for a coating and drying process, so the adhesion process can be completed in a short time, making it possible to perform the adhesion process very quickly. There is no need for process control regarding uneven coating, uncoated areas, etc. in the coating process. Since volatile substances such as solvents are not generated during the bonding process, the work environment is not deteriorated and it is advantageous in terms of occupational safety and health for workers. In addition, since no solvents are used, there is no risk of fire such as ignition or explosion.
Because the pre-product is sandwiched between adherends and the reaction is caused by pushing out air by applying pressure and heating, the workability is related to the viscosity stability of the adhesive itself, which is similar to ordinary adhesives. Inconsistencies in adhesive properties have been eliminated, errors in two-component mixing and measuring have been eliminated, and the crosslinking speed is extremely fast, so that when it comes out of a press or other pressure machine, it has already reached practical strength, which is unique to two-component reactive adhesives. Since there is no need for reaction curing time, which would otherwise be required, it is not only extremely useful for energy saving and cost reduction, but also because it does not require as many man-hours as in the conventional bonding process, it is easier to obtain a more uniform bonded state, and the final product There is also little variation. In addition, since the base material of the adhesive is rubber, there is less adhesive fatigue caused by shock, vibration, and distortion due to the difference in linear expansion coefficient between the adherend and the adhesive layer, which helps extend the durability of the bonded part. Since the adhesive layer is a vulcanized rubber layer, it is strong and exhibits good adhesion even at high temperatures. As described above, the present invention greatly improves the quality control of adhesives, the work control of the bonding process, the environmental control of the workplace, the disaster prevention management, etc., and makes a great contribution to product quality control. Olefin-based synthetic rubber, which has been considered difficult to bond to unvulcanized fabrics, as well as vulcanized fabrics, firmly adheres to it, and because vulcanization adhesion is achieved, it has the characteristic of exhibiting good adhesion even in high-temperature environments. This is a revolutionary invention. Further, in the present invention, by combining a film having no adhesive ability on one side, a protective layer having an arbitrary thickness can be easily produced. Since the adhesive of the present invention is based on olefin rubber, it can be shaped into any shape by applying pressure.
It can be used for a wide range of applications, from paints to linings, as it can provide a uniform film thickness on flat surfaces and curved surfaces, as well as a beautiful finish, and has excellent weather resistance and other durability. Conceivable. Examples of the olefinic synthetic rubber used in the present invention include ethylene-propylene copolymer, isobutylene rubber, isobutylene-diene copolymer, and chlorosulfonated polyethylene. The organic peroxides used in the present invention include benzoyl peroxide, 1,1-bis(tert-butylperoxy)3,3,5-trimethylcyclohexane, tert-butylcumyl peroxide, 2,5-dimethyl-2, 5-ditertiarybutylperoxyhexane, 2,5-dimethyl-2,5-dibenzoylperoxyhexane,
It is used as a crosslinking agent for common general-purpose rubbers such as dicumyl peroxide, but it is more preferable to use one that decomposes less at room temperature. In addition, vulcanization accelerators, vulcanization retarders, fillers, antifoaming agents,
A tackifier, anti-aging agent, preservative, anti-mold agent, etc. may be added. The method for obtaining the adhesive of the present invention is to knead the materials using a machine used for kneading in the rubber industry, such as a pressure kneader, Banbury mixer, open roll, etc., and then form the film into a film using a calendar roll, extruder, etc. Although it is possible to manufacture easily and inexpensively by a method of molding into a shape, the present invention is not limited to the above manufacturing method. The present invention will be explained in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and Comparative Examples. Table 1 shows the formulations of Examples and Comparative Examples.
In addition, the unit is expressed in parts by weight. Table 2 shows the test results and vulcanization conditions of Examples and Comparative Examples. The test method is described separately (page 11). Table 3 shows the test results of adhesion between various rubber sheets and various metal plates. The test conditions are as follows. (1) Vulcanization conditions for adhesive Conditions for simultaneous vulcanization of unvulcanized rubber sheet, adhesive, and various metal plates 150℃ x 50Kg/cm ² x 5 minutes (Press temperature x Press pressure x Press time) Vulcanization Vulcanization conditions for adhesives between rubber sheets and various metal plates: 150°C x 20Kg/cm ² x 5 minutes (pressing temperature x
(Press pressure x Press time) (2) Type of adhesive Example 1 (3) Judgment Excellent: Broken rubber sheet. Good: Peeling at the adhesive-metal plate interface, but strong adhesive strength. Table 4 shows the test results for adhesion between metals. The test conditions are (1) Vulcanization conditions 150℃ x 50Kg/cm ² x 5 minutes (Press temperature x Press pressure x Press time) (2) Type of adhesive Example 1 (3) Judgment Excellent: Adhesive shows cohesive failure. Good: Indicates interfacial failure of the adhesive, but the adhesive strength is strong. Table 5 shows the adhesive strength test results at each ambient temperature. The test conditions are as follows. When the type of adhesive is Example 1 (1) Vulcanization conditions: 150°C x 20Kg/cm ² x 5 minutes (Press temperature x Press pressure x Press time) (2) Adherent: Vulcanized ethylene propylene copolymer Rubber and polished iron plate If the type of adhesive is a solvent-based general-purpose chloroprene rubber adhesive (1) Adhesive conditions: Apply the adhesive to the iron plate, dry it, then press the vulcanized rubber sheet with a rubber roll. (2) Adherent: Vulcanized chloroprene copolymer rubber and polished iron plate Test method After leaving each test piece in each atmosphere of 20℃, 50℃, 80℃, 100℃, and 130℃ for 20 minutes, the atmosphere Peel adhesion strength is measured at temperature. Method for preparing specimens Layer a film-like vulcanized adhesive on various metal plates as adherends, and attach each adherend (unvulcanized rubber sheet,
Vulcanized rubber sheets, various metal plates) were stacked on top of each other, and samples were prepared under the vulcanization conditions specified separately. The test method in Table 2 is shown below. 1. Storage stability After leaving the film-form vulcanized adhesive in an atmosphere of 50°C for 6 months, check the appearance and adhesive strength. 2 Adhesive Strength (Peel Adhesive Strength) According to JIS-K-6854 (Peel Adhesive Strength Test Method). 3 Bending resistance Observe the condition when bent using a 2mmφ mandrel.

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[Table] As is clear from the Examples and Comparative Examples, the present invention uses 10 to 80 parts by weight of zinc white, 5 to 40 parts by weight of acrylic acid and/or methacrylic acid, and organic filtrate to 100 parts by weight of ethylene propylene copolymer rubber. Vulcanized adhesives made of oxides are capable of simultaneously vulcanizing and adhering unvulcanized rubber sheets and various metals;
It also makes it possible to bond metals together and metals and vulcanized rubber. In the present invention, 10 to 80 parts by weight of zinc white is used for 100 parts by weight of olefinic synthetic rubber.
If the amount of zinc white is less than 10 parts by weight, vulcanization cannot be performed in a short time, and even if vulcanization is performed for a long time, the adhesive layer has no rubber elasticity and is soft, so adhesive strength cannot be secured. On the other hand, if it exceeds 80 parts by weight, the storage stability of the rubber adhesive will be impaired, the rubber elasticity of the adhesive layer after vulcanization will be reduced, and the processing performance of the vulcanized product will be reduced, which is not preferable. Further, in the present invention, acrylic acid and/or methacrylic acid is added in an amount of 5 to 5 parts by weight per 100 parts by weight of the synthetic rubber.
40 parts by weight is added, but if the organic acid is less than 5 parts by weight, the adhesive layer becomes soft regardless of the vulcanization conditions, resulting in a significant decrease in adhesive strength, whereas if the amount added exceeds 40 parts by weight, the adhesive layer becomes weak The storage stability of the adhesive deteriorates, and the vulcanized adhesive layer also loses its rubber elasticity and becomes hard and brittle, resulting in an extremely poor bending performance, causing problems in processing performance. Table 8 shows the results of simultaneous vulcanization adhesion tests between various metal plates and unvulcanized rubber sheets, as well as vulcanization adhesion tests between vulcanized rubber sheets.As is clear from this table, ethylene-propylene copolymer rubber Co-vulcanization adhesion with various metals is particularly excellent. Table 4 shows the adhesion status of various metal plates.
All are in good condition. Table 5 shows the adhesive strength test results in a high temperature atmosphere, and the adhesive of the present invention has a high adhesive strength retention rate at high temperatures. As is clear from the above, the film-like vulcanized rubber adhesive of the present invention can not only be used for simultaneous vulcanization adhesion of general-purpose unvulcanized rubber sheets and metals by press bonding, but also difficult to bond with conventional materials. Co-vulcanization adhesion with warm olefin synthetic rubber is particularly excellent. Furthermore, it has excellent adhesion between vulcanized rubbers, between metals, and between vulcanized rubber and metals, and because the adhesive layer has excellent flexibility, it has good processability.
Also, it has excellent adhesion in a high temperature atmosphere. Furthermore, unlike amorphous adhesives such as solution type or two-component reaction type, it is a regular adhesive and has excellent storage stability, which makes it difficult to manage adhesive quality, work management of the bonding process, and the environment. A great deal of labor and economic waste can be saved from management, disaster prevention management, and product quality control. The present invention has many advantages as described above and will make a great contribution to industrial development.

Claims (1)

[Claims] 1 For 100 parts by weight of olefin-based synthetic rubber,
A film-like film characterized in that a composition is formed by sequentially adding and blending 10 to 80 parts by weight of zinc white, 5 to 40 parts by weight of acrylic acid and/or methacrylic acid, and an organic peroxide. Vulcanized rubber adhesive.