JPH0226661B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention involves kneading 10 to 80 parts by weight of zinc white with respect to 100 parts by weight of olefinic synthetic rubber, and then sequentially adding and blending 5 to 40 parts by weight of acrylic acid and/or methacrylic acid and an organic peroxide. As a necessary condition,
The present invention relates to a vulcanized rubber adhesive that is dissolved or dispersed in an aromatic solvent or a mixed solvent of aromatic and aliphatic solvents. The above-mentioned vulcanized rubber adhesive is an adhesive for bonding any adherend, such as metals such as iron and aluminum, various vulcanized rubbers, and various unvulcanized rubbers, etc., and has a dry film thickness on one side of the adherend. The adhesive is coated to a thickness of 10μ or more, pre-dried at a temperature that makes it difficult for the organic peroxide to decompose, and then the other adherend is layered and the adhesive is vulcanized under pressure and heat. A good adhesion condition can be obtained. The vulcanization conditions are that when adhering adherends together, pressure is applied so that there is no air between these adherends and the adhesive of the present invention, and heating is applied for several minutes at a temperature above the decomposition temperature of the organic peroxide. Sulfurize. Incidentally, when unvulcanized rubber or unvulcanized rubber and various adherends are vulcanized and bonded together using the vulcanizable adhesive of the present invention, simultaneous vulcanization is also possible. Conventionally, rubber-metal vulcanization adhesives are made using rubber rolls,
It is used for rubber linings, electric wire coatings, valves, hoses, belts, anti-vibration rubber, oil seals, etc., and the method of using glue containing the elastomer to be bonded has been used for a long time. ing. This method uses a highly hard composition containing a large amount of metal oxide as a primer formulation on the metal side, and a highly elastic composition with a high rubber content as a stock formulation on the rubber side, resulting in a vibration-resistant final adhesive product. Although it has the characteristics of being strong and impact resistant, 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 to the metal surface of the adherend, dried, a topcoat adhesive is applied and dried, and unvulcanized rubber fabrics, etc. are simultaneously vulcanized and bonded. There is. This adhesive is capable of simultaneous vulcanization bonding of most unvulcanized rubber fabrics and metals, but there are problems with simultaneous vulcanization bonding of olefin-based synthetic rubber and metals, and a special adhesive is required. . Furthermore, since the primer and adhesive must be applied and dried twice, it takes many man-hours and is economically wasteful. In addition, one-component adhesives containing isocyanate compounds, etc. in a phenolic resin solution have excellent heat resistance and oil resistance, and have excellent adhesion to general-purpose synthetic rubber and natural rubber, but they have problems with flexibility. Because of this, it has drawbacks such as peeling at cut ends and bent parts during product processing. Adhesives for vulcanized rubber include polar rubbers such as chloroprene rubber, acrylonitrile-butadiene copolymer 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 adhesives. Adhesion between synthetic rubber and metal is also extremely difficult. The present invention eliminates these drawbacks and contains 10 to 10 parts of zinc white per 100 parts by weight of olefin-based synthetic rubber.
After kneading 80 parts by weight, it is dissolved or dispersed in an aromatic or aromatic and aliphatic mixed solvent with the essential condition of blending 5 to 40 parts by weight of acrylic acid and/or methacrylic acid and an organic peroxide. It is a vulcanized rubber adhesive. Since this adhesive is an adhesive, it is possible to not only simultaneously vulcanize and bond unvulcanized rubber sheets and metals, but also bond vulcanized rubbers and metals together by press bonding. It is also possible to bond with olefin-based synthetic rubber, which has been difficult to bond with in the past. Furthermore, since it is a one-component coating type adhesive and the adhesive layer is non-adhesive after drying, it reduces the number of working steps and is excellent in workability. Furthermore, since the main component is olefin-based synthetic rubber, it has excellent flexibility and processability, and also has excellent adhesion in high-temperature atmospheres. Furthermore, since an aromatic solvent or a mixed aromatic and aliphatic solvent is used as the organic solvent, it has excellent storage stability even though it is a one-component coating type adhesive. The olefin-based synthetic rubber used in the present invention includes ethylene-propylene copolymer, isobutylene-based, isobutylene-diene copolymer, chlorosulfonated polyethylene, and the like. Examples of 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,
Dicumyl peroxide and the like are commonly used as crosslinking agents for synthetic rubber, but those that are less likely to decompose at room temperature are more preferred. The organic solvents used in the present invention include aromatic solvents such as toluene, xylene, and ethylenebenzene, and aliphatic solvents such as pentane, hexane, heptane, octane, methylcyclohexane, and cyclohexane. In addition, vulcanization accelerators, vulcanization retarders, fillers, antifoaming agents, tackifiers, anti-aging agents, preservatives and
It is also possible to add a fungicide or the like. The vulcanized rubber adhesive of the present invention is prepared by kneading synthetic rubber with zinc white, acrylic acid, and/or methacrylic acid in this order using the above-mentioned materials and dissolving or dispersing it in an appropriate amount of an organic solvent depending on the application method. It can be obtained by blending an appropriate amount of organic peroxide. There are various methods for applying this vulcanized rubber adhesive, such as roll coating, bar coating, spraying, and brushing, but the viscosity can be freely adjusted using an organic solvent. Further, depending on the type of metal and the type of synthetic rubber selected, it is possible to provide even stronger adhesion to the surface to be adhered by subjecting the surface to an appropriate surface treatment. The present invention will be explained in detail with reference to Examples and Comparative Examples. Table 1 shows the formulations of Examples and Comparative Examples. The units are parts by weight. Table 2 shows the test results and vulcanization conditions of Examples and Comparative Examples. The test method is described separately (page 10). Table 3 shows the test results of adhesion between various rubber sheets and various metal plates. The test conditions are (1) Adhesive vulcanization conditions: conditions for simultaneous vulcanization of the unvulcanized rubber sheet, adhesive, and various meter plates.
150℃ x 50Kg/cm ² x 5 minutes (Press temperature x Press pressure x Press time) Vulcanization conditions for adhesive between vulcanized rubber sheet and various metal plates 150℃ x 20Kg/cm ² x 5 minutes (Press temperature x (Press pressure x Press time) (2) Type of adhesive: Example 1 (3) Judgment Excellent: Breakage of the rubber sheet Good: Peeling at the adhesive-metal plate interface, but the adhesive strength is strong Table 4 shows The results of a metal-to-metal adhesion test are shown. 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 Good: Indicates interfacial failure of the adhesive, but the adhesive strength is high Table 5 shows the results of the adhesive strength test at each ambient temperature. The test conditions are 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: vulcanization When the type of adhesive for sulfur ethylene propylene copolymer rubber and polished iron plate is a solvent-based general-purpose chloroprene rubber adhesive (1) Adhesive conditions: Apply the adhesive to the iron plate, dry it, and 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 ambient temperature was determined. Measure the peel adhesion strength. How to prepare the specimen The dry weight of various metal plates as adherends is approximately 40g/
^m2 , dried for 20 minutes in an atmosphere of 80℃, and bonded each adherend (unvulcanized rubber sheet, vulcanized rubber sheet, various metal plates) to create a sample under the vulcanization conditions specified separately. did. The test method in Table 2 is shown below. 1 Solution viscosity According to JIS-K-6833 general test method for adhesives.
BH type viscometer No. 7 rotor, 2 rotations, 25℃ conditions. 2 Storage Stability After leaving the solution adhesive in an atmosphere of 50°C for 30 days, check the condition and adhesive strength. 3 Adhesive strength (peel adhesive strength) According to JIS-K-6854 adhesive peel strength test method. 4 Bending resistance Observe the condition when bent using a 2mm mandrel.

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[Table] *1 Shows the adhesive strength when a polished iron plate and ethylene propylene copolymer rubber are simultaneously vulcanized and bonded.

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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 peroxide to 100 parts by weight of ethylene propylene copolymer rubber. A vulcanized adhesive consisting of a material is capable of simultaneous vulcanization bonding of an unvulcanized rubber sheet and various metals, and is also capable of bonding vulcanized rubbers together, metals together, and metals and vulcanized rubbers. . In the present invention, 10 to 80 parts by weight of zinc white is used for 100 parts by weight of olefin-based synthetic rubber, but if the zinc white is less than 10 parts by weight, vulcanization cannot be performed in a short time, and even if vulcanization is carried out for a long time, However, the adhesive layer has no rubber elasticity and is soft, making it impossible to secure adhesive strength. while 80
Exceeding the weight part is undesirable because there is a high possibility that the rubber adhesive will gel, making it difficult to apply and at the same time reducing the rubber elasticity of the adhesive layer after vulcanization, which will reduce the processing performance of the vulcanized molded product. . In addition, 5 to 40 parts by weight of acrylic acid and/or methacrylic acid is added to 100 parts by weight of the synthetic rubber, but if the organic acid is less than 5 parts by weight, the adhesive layer becomes soft regardless of the vulcanization conditions and the adhesive strength decreases. On the other hand, if the amount added exceeds 40 parts by weight, the storage stability of the adhesive deteriorates, often gelling within a few days of indoor storage, and the vulcanized adhesive layer also loses its rubber elasticity and becomes hard. It becomes brittle and its bending performance is extremely reduced, causing problems in processing performance. Table 3 shows the results of simultaneous vulcanization adhesion tests between various metal plates and unvulcanized rubber sheets, and vulcanization adhesion tests between vulcanized rubber sheets.As is clear from this table, ethylene-propylene copolymer rubber and various Co-vulcanization adhesion with metals is particularly excellent. Table 4 shows the state of adhesion between various metal plates, and all of them are good. 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 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 olefin-based composites, which have been difficult to bond with in the past. Particularly excellent co-vulcanization adhesion with rubber. 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, and it also has good adhesion in high-temperature atmospheres. Are better. Furthermore, although it is a one-component adhesive, it has excellent storage stability, and the adhesive layer after application and drying is non-tacky, making it even more workable and of great industrial value. .

Claims (1)

[Claims] 1 For 100 parts by weight of olefin-based synthetic rubber,
After kneading 10 to 80 parts by weight of zinc white, add acrylic acid and/or
Alternatively, it is essential to sequentially add and blend 5 to 40 parts by weight of methacrylic acid and an organic peroxide, and dissolve or disperse it in an aromatic solvent or a mixed solvent of aromatic and aliphatic. A vulcanized rubber adhesive characterized by: