JPS6051767A - Film-form vulcanizing rubber adhesive - Google Patents

Abstract

PURPOSE:To provide the titled adhesive which has excellent bonding workability and is safe and hygienic and suitable for use in bonding metals to each other, by adding zinc flower, (meth)acrylic acid and an org. peroxide in sequence to a synthetic olefin rubber, and molding the mixture into a film. CONSTITUTION:10-80pts.wt. zinc flower, 5-40pts.wt. (meth)acrylic acid and an org. peroxide such as benzoyl peroxide or dicumyl peroxide are added in sequence to 100pts.wt. synthetic olefin rubber such as an ethylene/propylene copolymer or isobutylene rubber. The resulting compsn. is molded into a film to obtain the desired vulcanizing rubber adhesive. The film-form adhesive is put between adherends. The laminate is pressed in the absence of air and heated at a temp. not lower than the decomposition temp. of the org. peroxide for several min to give firm bonding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses 10 to 80 parts by weight of zinc white, 5 to 40 M parts of acrylic acid and/or methacrylic acid, and an organic peroxide to 100 parts by weight of olefinic synthetic rubber. The present invention relates to a film-like vulcanized rubber adhesive obtained by forming a rubber composition containing the following 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. By placing a film that has no adhesion ability at all, such as cellophane film, on one side as a protective agent for the rubber or metal surface, the surface can be protected by peeling off the upper fan film after vulcanization adhesion to the rubber or metal surface. 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 air is removed between the film-like vulcanized rubber adhesive of the present invention and the adherend using a press molding machine or the like. By applying gVc pressure and temperature, vulcanization of the rubber adhesive is completed in a short time and a strong adhesive state is achieved.

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 described above; past examples include methods using adhesive-impregnated paper for plywood production, heat-melting methods for food packaging, and felt-like adhesives 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, making the adhesive susceptible to vibrations, shocks, and temperature changes. It is susceptible to adhesive fatigue such as distortion due to the difference in coefficient of linear expansion between the adhesive layer and the adherend, and has shortcomings in durability.In addition, rubber-metal vulcanization has traditionally been used to bond rubber and metal. Adhesives are used for rubber rolls, rubber linings, electric wire coverings, pulp, hoses, belts, anti-vibration rubber, oil sol, etc. For these adhesives, co-glues containing a nidistomer to be bonded are used. This method has been used for a long time. This method uses a highly hard composition containing a large amount of gold 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. Since many types of walls are required to have properties such as strength and impact resistance, the process is complicated. 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

This adhesive is capable of simultaneous vulcanization bonding between most unvulcanized rubber fabrics and metals, but there are problems with simultaneous vulcanization bonding between olefin 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 incyanate 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 are not flexible. 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 extremely difficult adhesion to metals.

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. during 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. Additionally, since no solvents are used, there is no risk of fire such as ignition or explosion. Because the pre-made product is sandwiched between adherends and the reaction is carried out by pushing out air under pressure and heating, the workability is related to the viscosity stability of the adhesive itself, which is similar to ordinary adhesives. This also eliminates the variation in the two-part mixture and
Mistakes have been eliminated, and the crosslinking speed is extremely fast, so that when it comes out of the press or other press, it has already reached practical strength.
Since there is no need for the reaction curing time found in two-component adhesives, it is not only extremely useful for saving energy and reducing costs, but it also eliminates the large number of man-hours required in the conventional bonding process, resulting in a more uniform bonding process. It is easy to obtain a bonded state, and there is little variation in the final product.

In addition, since the base material of the adhesive is rubber, there is less adhesion fatigue caused by impact, photography, distortion due to the difference in linear expansion coefficient between the adherend and the adhesive layer, and it increases the durability of the bonded part. Although the length is not useful, the adhesive layer is made of a vulcanized rubber layer, so it is strong and exhibits good adhesion even at high temperatures.

As described above, the present invention greatly improves quality control of adhesives, work management of bonding processes, environmental management of workplaces, disaster prevention management, etc., and makes a significant contribution to product quality control.
Unvulcanized fabrics made of olefin synthetic rubber, which were conventionally considered difficult to bond at ℃, adhere strongly to both thermal and vulcanized fabrics, and vulcanization adhesion is achieved, making it possible to create adhesives that exhibit 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 formed into a fixed shape by applying pressure, but it can be applied to any shape, and a uniform film thickness can be obtained from flat surfaces to curved surfaces. It can also be used in a wide range of applications, from paint strength to lining, as it provides a beautiful finish and has excellent weather resistance and other durability.

Examples of the olefin-based synthetic rubber used in the present invention include ethylene-propylene copolymer, isobutylene rubber, inbutylene-diene copolymer, and chlorosulfonated polyethylene.

Examples of organic peroxides used in the present invention include benzoyl peroxide and 1,1-bis(tarjaleaf).

8,8,5-)dimethylcyclohexane, tertiarybutylperoxy), 2
．． 5-dimethyl-111,5-ditertiary-butydibenzoyl peroxyhexane, dicumyl peroxide, and the like are used as crosslinking agents for common general-purpose rubbers, but those that are less likely to decompose at room temperature are preferred. Furthermore, a vulcanization accelerator, a vulcanization retarder, a filler, an antifoaming agent, a tackifier, an anti-aging agent, a preservative, an anti-mold agent, etc. may be added as necessary.

The method of preparing the adhesive of the present invention is to knead the materials using a machine commonly used for mixing wires in the rubber industry, such as a pressure kneader, a Banbury mixer, or an open roll.
Although it can be easily and inexpensively produced by forming it into a film using a calendar roll, an extruder, etc., the present invention is not limited to the above production 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/curing conditions for Examples and Comparative Examples.

The test method is described separately (page 11).

Table 8 shows the results of adhesion tests between various rubber sheets and various metal plates.

The test conditions are as follows.

+1) Adhesive vulcanization conditions Simultaneous vulcanization of unvulcanized rubber sheet, adhesive, and various metal plates f
) Conditions 150°C x 50kyIIL2x 5 minutes (Press temperature x Press pressure x Press time) Vulcanization conditions for adhesive between vulcanized rubber sheet and various metal plates 150°C x 20kyIIL2 x 5
(Press temperature x Press pressure x Press time) (2) Type of adhesive Example 1 (B) Excellent judgment: Breakage of rubber sheet.

Good: Peeling at the adhesive-metal plate interface, but strong adhesive strength.

Table 4 shows the test results for adhesion between metals.

In addition, the test conditions are (11 vulcanization conditions 150°C Indicates cohesive failure.

Good: Indicates interfacial failure of adhesive, but adhesive strength is large.

Figure 5 shows the results of the adhesion test at each ambient temperature.

The test conditions are as follows.

When the type of adhesive is Example 1 (1) Vulcanization conditions: 150°C x 20kl'6H"
6 minutes (Press temperature x Press pressure x Press time) (2) Adherent: Vulcanized ethylene propylene copolymer rubber and polished iron plate When the type of adhesive is a solvent-based general-purpose chloroglene comb adhesive (1) Adhesion conditions: After applying the adhesive to the iron plate and drying it, press the vulcanized comb sheet with a rubber roll.

(2) Adherent: Vulcanized chloroprene copolymer rubber and polished iron plate Test method After placing each test piece in each atmosphere of 20°C, 50°C, 80°C, 100°C, and 180°C for 20 minutes, the atmosphere Peel adhesion strength is measured at temperature.

How to create the specimen: Lay a film-like vulcanized adhesive on each metal plate as the adherend, and overlap each adherend (unvulcanized rubber sheet, vulcanized rubber sheet, various metal plates), Samples were prepared under the vulcanization conditions specified separately.

The test method shown in Table 2 is shown below.

], the appearance and adhesion strength of the storage-stable film-form vulcanizable adhesive were confirmed after it was allowed to stand in a 50° C. atmosphere for 6 months.

2 Adhesive Strength (Peel Adhesive Strength) According to JIS-K-(1854 (Testing Method for Peel Adhesive Strength of Adhesives) K.

3 Oil bending resistance Observe the state when bent with a 2 mmφ mandrel.

*l is EPT F1045 manufactured by Mitsui Petrochemical Industries, Ltd.
(Product name) *2 is manufactured by Showa Neoprene Co., Ltd. Hypalon #80 (Product name) *8 is manufactured by Katayama Chemical Industry Co., Ltd. *4 is manufactured by Katayama Chemical Industry Co., Ltd. *5 is manufactured by Nippon Oil & Fats Co., Ltd. Bar Hexa 8M (product name)
*6 is Park Mill D (+tT) manufactured by Nihon Yushi Jashi Co., Ltd.
hProduct name) *7 is Niper B manufactured by Nippon Oil & Fats Co., Ltd. (Product name) Table-5 Adhesive strength test at each ambient temperature (Unit:
kgf/Z5mm) *l Adhesion of vulcanized ethylene propylene copolymer rubber and polished iron plate using the adhesive of Example 1 under the conditions of 150°C x 20cm x 5 minutes (press temperature x press pressure x press time) Show power.

*2 The adherend used was vulcanized chloroprene rubber.

As is clear from the Examples and Comparative Examples (10 to 10 parts by weight of zinc white per 100 parts by weight of ethylene propylene copolymer rubber),
80 parts by weight and 5 parts of acrylic acid and/or methacrylic acid
A vulcanized adhesive consisting of 40 parts by weight and 1 to 1 part of organic peroxide is capable of simultaneously vulcanizing and adhering an unvulcanized rubber sheet to various metals, and is capable of bonding vulcanized rubber together, metals together, and metals and vulcanized rubber. It is also capable of adhesion with other materials.

In the present invention, 10 to 80 parts by weight of zinc white is used per 100 parts by weight of olefinic synthetic rubber.
If the heavily rolled part is broken, vulcanization cannot be done in a short time, and even if it were to be vulcanized for a long time, the adhesive has no rubber elasticity and is soft, so adhesive strength cannot be ensured. 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, 5 to 40 parts by weight of acrylic acid and/or methacrylic acid are added to 100 parts by weight of the synthetic rubber, but if the organic acid is less than 5 parts by weight, the vulcanization conditions may be affected (adhesive layer On the other hand, if the amount added exceeds 40 parts by weight, the storage stability of the adhesive becomes poor (and the vulcanized adhesive layer also loses its rubber elasticity and becomes hard (brittle)).
This causes problems with processing performance because the bending performance is extremely reduced.

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.

The state of adhesion between various metal plates is shown at the top of the table, and all 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 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, but also difficult to bond with conventional materials by press bonding. The co-vulcanization adhesion with olefin-based 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 and can withstand high temperatures. Adhesion in atmosphere is also excellent.

Furthermore, unlike amorphous adhesives such as solution type or two-component reaction type, since it is a regular adhesive, it has excellent storage stability, which makes it suitable for quality control of adhesives, work management of the bonding process, etc. From environmental management, disaster prevention management, to product quality control,
A great deal of labor and economic waste can be saved.

The present invention has many advantages as described above and will make a great contribution to industrial development.

Patent applicant: Hayakawa Rubber Co., Ltd. Same applicant: Takuma Matsumoto

Claims (1)

[Claims] 1 A composition prepared 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 to 100 parts by weight of olefinic synthetic rubber. A film-like vulcanized rubber adhesive characterized by being molded into a film.