JP2816909B2 - Method for producing rubber-rubber bonded composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, at least two types of rubber compositions containing the raw rubber component of the same or different
The present invention relates to a method for producing a rubber-rubber bonded composite in which rubber materials are used and the rubber materials are bonded to each other.

[0002]

2. Description of the Related Art Conventionally, rubber-rubber composites such as tires, conveyor belts, hoses and lining products are obtained by molding a plurality of types of rubber compositions into a rubber material and laminating these unvulcanized rubber materials. It is manufactured by vulcanization bonding. However, when the above rubber materials are laminated, the compatibility between the unvulcanized rubber materials is poor, or the vulcanization speed and the cross-linking form are significantly different, so that there is no so-called co-vulcanization property. There is a problem that a bonded rubber / rubber bonded composite cannot be obtained. In addition, the compounding chemicals contained in the rubber material are diffused and transferred to each other, and the vulcanization characteristics of the rubber material change, so that a rubber-rubber bonded composite having good quality and performance cannot be obtained.

[0003] Further, when at least one of the rubber materials is vulcanized, it is very difficult to adhere, and as a countermeasure, it is difficult to sufficiently adhere even if an adhesive or the like is used. However, there is a drawback that the flexibility of the rubber-rubber adhesive composite is reduced because of the hardness. Furthermore, this adhesive did not exhibit any effect other than bonding, such as a reinforcing effect.

The inventor of the present invention has developed an excellent adhesive which firmly joins rubber materials made of a rubber composition containing a specific same or different raw rubber component to an ultra-high molecular weight polyethylene sheet produced by a cutting method. And proposed. However, since this ultra-high molecular weight polyethylene sheet is sheet-shaped, it is difficult to firmly bond a rubber material having a complicated shape or a rubber material preformed before bonding, so that the types of rubber products that can be commercialized are However, there is a problem that is greatly restricted.

[0005]

SUMMARY OF THE INVENTION According to the present invention, two or more types of rubber compositions are used as rubber materials, respectively, and the co-vulcanizability between these rubber materials and the presence or absence of vulcanization of the rubber materials are firm. A method for producing a rubber-rubber bonded composite that provides a number of useful properties, such as adhering to rubber, preventing diffusion of the compounded components in the rubber material after bonding, and giving the adhesive a number of useful properties such as not hindering flexibility. The purpose is to do. Another object of the present invention is to provide a method for producing a rubber-rubber composite that can firmly adhere these rubber materials to each other regardless of the shape of the rubber material or the presence or absence of a preform. Aim.

[0006]

In order to achieve the above object, a method for producing a rubber-rubber bonded composite according to the present invention comprises the steps of: starting raw rubber contained in a rubber composition constituting the rubber-rubber bonded composite; Different types of components, vulcanization of rubber materials,
Intrinsic critical surface tension γc of unvulcanized and raw rubber components
Are divided into the following four modes. That is, in the first invention of the present invention, the critical surface tension γc (hereinafter, abbreviated as γc) is 25 to 35 millinewton / meter (hereinafter, mN).
/ M), two unvulcanized rubber compositions each containing the same type of raw rubber component were used as rubber materials, and ultra-high molecular weight polyethylene powder was interposed between these rubber materials. This is a method in which the obtained laminate is heated to a temperature equal to or higher than the melting temperature of the ultrahigh molecular weight polyethylene powder, that is, a temperature equal to or higher than the melting point of the ultrahigh molecular weight polyethylene, to vulcanize the rubber material and to fuse and integrate.

According to a second aspect of the present invention, γc is 25 to 32.
Two rubber compositions each containing mN / m of the same type of raw rubber components are used as rubber materials, and a vulcanized rubber material is used for at least one of these rubber materials. After laminating with a high molecular weight polyethylene powder interposed therebetween, the resulting laminate is heated to a temperature equal to or higher than the melting temperature of the ultrahigh molecular weight polyethylene powder to be fused and integrated.

[0008] In a third aspect of the present invention, both γc are 25 to 25.
Containing 30 mN / m disparate raw rubber component respectively
At least two types of rubber compositions each with a rubber material
And at least two of these rubber materials are unvulcanized
Combination of rubber material, unvulcanized rubber material and vulcanized rubber material
Or vulcanized rubber material, and after laminating between these rubber materials with an ultra-high molecular weight polyethylene powder interposed, the resulting laminate is heated to a temperature equal to or higher than the melting temperature of the ultra-high molecular weight polyethylene powder. This is a method of fusing and integrating by heating.

Further, in the fourth invention of the present invention, one of them is γ.
with c is an unvulcanized rubber material formed of a rubber composition containing a raw rubber component of 30~35mN / m, comprising one from the rubber composition γc contains raw rubber component of 25~30mN / m An unvulcanized rubber material or a vulcanized rubber material, and after laminating with an ultra-high molecular weight polyethylene powder interposed between these rubber materials , the obtained laminate is melted with the ultra-high molecular weight polyethylene powder. This is a method of fusing and integrating by heating to a temperature not lower than the temperature.

As described above, the present invention provides a laminate in which an ultra-high molecular weight polyethylene powder is interposed between rubber materials obtained by molding a rubber composition containing the same or different raw rubber components having a specific γc. Heating this laminate to melt the ultra-high molecular weight polyethylene powder and fusing and integrating with the rubber material, the shape of the rubber material is complicated,
Even if preformed, it can be firmly bonded. In addition, bonding can be performed regardless of the co-vulcanization properties of the rubber materials and the presence or absence of vulcanization. Moreover, since the ultra-high molecular weight polyethylene powder is formed into a film after bonding and prevents the diffusion and transfer of the compound components between the rubber materials,
Variations in the vulcanization characteristics of these rubber materials can be prevented. In addition, since the film-like adhesive layer made of this ultra-high molecular weight polyethylene powder is flexible and easily bent, the flexibility of the rubber-rubber adhesive composite is not reduced, and the strength,
Numerous performances such as air retention, gas permeation resistance, and water resistance can be improved.

In the present invention, the critical surface tension γc is
On August 20, 1978 (3rd printing), published in Maruzen Co., Ltd., "Chemical Handbook" Basic Edition II, p. 618,
Assuming that the contact angle of a homologous series of liquid hydrocarbons and other organic liquid compounds on a solid surface is θ and the surface tension of the liquid is γ, the relationship between cos θ and γ is approximately one, regardless of the type of homolog. It becomes a straight line of a book. At this time, θ = 0, that is, cos θ =
It is defined as the value of γc corresponding to 1.

However, the critical surface tension γc of the raw rubber component defined in the present invention can be determined similarly by using a rubber sample in which the raw rubber component whose γc is to be measured is flattened by hot pressing instead of the above solid. It refers to the measured value. In the first invention of the present invention, it is necessary to use two rubber compositions containing the same kind of raw rubber component having γc of 25 to 35 mN / m.

If the γc of the raw rubber component contained in the rubber composition is outside the above range, a rubber material having good adhesion to the ultrahigh molecular weight polyethylene powder cannot be obtained. That is, since γc of the raw rubber component is close to γc of polyethylene = 29 mN / m, it is considered that the affinity of the rubber material to the ultrahigh molecular weight polyethylene powder is increased, and the adhesiveness by fusion is improved.

As the raw rubber component having a γc in the range of 25 to 35 mN / m, 1988
Decker (Marcel Dekker, Inc., New York and Base
l) “Handbook of Elastomers New Development and Technology” (Handbo
ok of Elastomers New Development and Technology):
A, K, Bhowmik and H, L, Stephens, Chapter 8, Chapter 2
Isobutylene-isoprene copolymer rubber (IIR, γc = 27 mN / m), ethylene-propylene diene terpolymer rubber (EPD) described in Table 1 on page 53
M, γc = 28 mN / m), natural rubber (NR, γc = 3
1 mN / m), polybutadiene rubber (BR, γc = 32
mN / m), styrene-butadiene copolymer rubber (SB
R, γc = 33 mN / m).

A rubber composition is prepared by compounding a vulcanizing agent such as sulfur, a reinforcing agent such as carbon black, an antioxidant, a vulcanization accelerator and other compounding chemicals with the raw rubber component. The amount of the raw rubber component is preferably an amount occupying 50% by weight or more of the raw rubber component in the rubber composition. The obtained rubber composition is preformed into a rubber material having an arbitrary stackable shape such as a sheet shape or a plate shape. These rubber materials may be reinforced with metal cords such as steel cords, cords made of various organic fibers such as nylon, polyester, and aramid.

Next, the respective rubber materials produced using the two rubber compositions are appropriately combined, and
In the meantime, the layers are laminated with an ultra-high molecular weight polyethylene powder interposed therebetween. This ultra high molecular weight polyethylene powder has a molecular weight of 10
It is made of polyethylene of more than 100,000 and has an average particle diameter of 5
It is preferably from 0 to 300 μm. When the molecular weight is 1,000,000 or more, the adhesion to the rubber material can be further increased, and the physical properties thereof can be improved. Further, by setting the average particle diameter to 50 μm or more, it is possible to manufacture a rubber-rubber bonded composite having excellent bonding strength between rubber materials. On the other hand, by setting the average particle diameter to 200 μm or less, ultra-high molecular weight polyethylene powder can be evenly interposed between the rubber materials, and a thin film-like adhesive layer having a small thickness can be formed.

The means for interposing the ultrahigh molecular weight polyethylene powder between the rubber materials is not particularly limited. For example, there is a method in which ultra-high molecular weight polyethylene powder is directly sprayed on the surface of a rubber material or mixed with an oil such as liquid paraffin to prepare a paste, and the paste is applied. The rubber-rubber laminate having the ultra-high molecular weight polyethylene powder having excellent affinity for rubber and firmly bonding by fusion is heated to a temperature not lower than the melting point (125 ° C.) of ultra-high molecular weight polyethylene. Thereby, the unvulcanized rubber material can be vulcanized and fused and integrated to form a rubber-rubber bonded composite. If the heating temperature of the laminate is too high, the ultra-high molecular weight polyethylene powder is liable to be thermally decomposed and deteriorated. By this heating, the ultrahigh molecular weight polyethylene powder melts to form a thin and flexible film-like adhesive layer excellent in strength, tensile elasticity, air retention, gas permeability resistance, moisture permeability resistance and the like. For this reason, the rubber-rubber adhesive composite has excellent dimensional stability while securing its flexibility. Moreover, since the film-like adhesive layer made of ultra-high molecular weight polyethylene prevents the diffusion and transfer of compounding chemicals between rubber materials, vulcanization characteristics such as co-vulcanization properties between rubber materials and vulcanization conditions such as vulcanization temperature. In addition, they can be bonded with or without vulcanization.

According to a second aspect of the present invention, γc is 25 to 32.
Two rubber compositions each containing mN / m of the same kind of raw rubber component are used as rubber materials, at least one of these rubber materials is vulcanized, and the other is left unvulcanized and combined. It is a method to use. However, the vulcanized rubber material used in the second invention is γ
It is necessary that c be composed of a rubber composition containing a raw rubber component of 25 to 32 mN / m. This is because, when the rubber material is vulcanized, a cross-linked structure is formed in the rubber, and the change in the molecular structure of the rubber accompanying this cross-linking substantially increases γc, and the rubber material with respect to the ultra-high molecular weight polyethylene powder This is because the adhesiveness is reduced. The second invention of the present invention is to increase the affinity between the vulcanized rubber material and the high-molecular-weight polyethylene powder by setting the upper limit of γc close to γc = 29 mN / m of polyethylene, and to achieve good fusion. Adhesion can be obtained.

This vulcanized rubber material is made of ultra-high molecular weight poly
After laminating the unvulcanized rubber material or the vulcanized rubber material described above with ethylene powder interposed , the resulting laminate is heated to a temperature equal to or higher than the melting temperature of the high molecular weight polyethylene powder, and in the same manner as described above. The rubber-rubber composite can be manufactured by fusion and integration. Next, the third invention, at least two of the rubber composition γc both contain 25~30mN / m disparate raw rubber component of each of the present invention
A method for producing a rubber-rubber bonded composite by using a heat-melt ultra-high molecular weight polyethylene powder by heating and melting the ultra-high-molecular-weight polyethylene powder using these rubber materials as in the first invention of the present invention. is there. In the third invention, it is necessary to use two or more types of rubber compositions each containing a different kind of raw rubber component having a γc of 25 to 30 mN / m. The combination of rubber materials may be both unvulcanized, one unvulcanized, the other vulcanized, and both vulcanized. Examples of the raw rubber component having γc in the above range include IIR and EPDM.

The fourth invention of the present invention is a method of bonding rubber materials made of rubber compositions containing different kinds of raw rubber components having different ranges of γc via ultrahigh molecular weight polyethylene powder. In the fourth invention, the rubber material on one side is composed of a rubber composition containing a raw rubber component having a γc larger than γc (29 mN / m) of ultrahigh molecular weight polyethylene having an MW of 30 to 35 mN / m, Use unvulcanized. This is because, in the rubber composition containing the raw rubber component having a large γc in the above range, γc is further increased by vulcanization, and γc (= 29 mN /
m) becomes too large and the adhesiveness decreases,
The rubber material is used in an unvulcanized state to ensure good adhesion to ultra high molecular weight polyethylene powder. The rubber composition on the other side has a low γc of 25 to 30.
A rubber composition using a raw rubber component of mN / m is used. The rubber material comprising the rubber composition may be unvulcanized or vulcanized.

The two rubber materials are laminated via an ultra-high molecular weight polyethylene powder in the same manner as in the first to third inventions.
The obtained laminate is heated to a temperature equal to or higher than the melting temperature of the ultrahigh molecular weight polyethylene powder to be fused and integrated to produce a rubber-rubber bonded composite.

[0022]

【Example】

Experimental Example 1 Five types of rubber compositions having the compounding compositions shown in Table 1 were prepared. As shown in Table 2, as shown in Table 1, the rubber compositions No. 1 (raw rubber component NR), No. 2 (raw rubber component EPDM),
No. 3 (raw rubber component SBR-NR), No. 4 (raw rubber component IIR) and No. 5 (raw rubber component NBR)
Each was molded into two sheet-like rubber materials of 150 mm × 50 mm × 2.5 mm.

The rubber material composed of the same type of rubber composition is used as an unvulcanized combination, and ultra-high molecular weight polyethylene powder (average particle size: about 5,000,000) and liquid paraffin are coated on the surface of each rubber material. The paste was mixed uniformly at a weight ratio of 100: 50, and then laminated, and heated at 150 ° C. for 30 minutes under a pressure of 20 kg / cm ² to produce a rubber-rubber adhesive composite. The adhesiveness of the obtained rubber / rubber adhesive composite was evaluated by the following method, and the results are shown in Table 2.

[0024] All numerical values in Table 1 are parts by weight.

* 1 is N-phenyl-N'-isopropyl-p-phenylenediamine * 2 is Nt-butyl-2-benzothiazolesulfenamide * 3 is tetramethylthiuram disulfide * 4 is 2-mercapto Benzothiazole * 5 is tetramethylthiuram monosulfide * 6 is benzothiazyl disulfide. Evaluation method of adhesiveness : The adhesiveness of the rubber-rubber adhesive composite
It is not accurate to evaluate by the magnitude of the adhesive force. Therefore,
A sample having a width of 20 mm was prepared and subjected to a peeling test. When interfacial peeling occurred, it was evaluated as poor (x) even if the adhesive strength was high. On the other hand, when no interfacial peeling occurred, a sheet having a thickness of about 0.5 mm was cut out with a razor around the adhesive interface of the rubber-rubber adhesive composite, and the thin piece was immersed in toluene and swollen. After that, when the interface peeling did not occur even when tension was applied to the vicinity of the adhesive interface while immersed in toluene, the adhesive property was evaluated as good (O).

[0026] From Table 2, it can be seen that all but NBR with γc of 39 mN / m show good adhesiveness. Experimental Example 2 As shown in Table 3, the rubber composition No. 1 in Table 1 was used. Using 1 to 5, any one of the rubber materials composed of the same type of unvulcanized rubber composition, as a vulcanized rubber material,
A paste obtained by mixing ultra- high molecular weight polyethylene powder with liquid paraffin was applied to the surface of these rubber materials, and then laminated, and then heated and fused and integrated. The adhesion of the obtained rubber-rubber composite was evaluated, and the results are shown in Table 3.

[0027] The raw rubber component is SBR (γc = 33 mN / m) 70: N
R (γc = 31 mN / m) 30 (weight ratio) rubber composition No. In the case of 3, if one of the rubber materials is vulcanized, good adhesion cannot be obtained. On the other hand, when γC of the raw rubber component is in the range of 25 to 32 mN / m, it can be seen that even if at least one of the rubber materials is vulcanized, good adhesiveness is obtained. Experimental Example 3 As shown in Table 4, the rubber composition No. 1 in Table 1 was used. 2 (EPD
M) and No. 4 (IIR) and No. 4 2 (EPDM) and No. 2 Regarding a combination of rubber compositions containing 1 (NR) different types of raw rubber components, both are unvulcanized, one of them is unvulcanized, the other is vulcanized, and both are vulcanized rubber materials. A paste obtained by mixing ultra- high molecular weight polyethylene powder with liquid paraffin was applied on the surface, and then laminated, and then heated and fused and integrated. The adhesion of the resulting rubber-rubber composite was evaluated, and the results are shown in Table 4.

[0028] As can be seen from Table 4, when a rubber composition containing different types of raw rubber components is combined, depending on γc of the raw rubber component and the vulcanized state of the rubber material (whether unvulcanized or vulcanized),
Adhesion is different. The γc value of the raw rubber component is 25 to
EPDM within the range of 30 mN / m (γc = 28 mN
/ M) and IIR (γc = 27 mN / m) have good adhesion regardless of the vulcanized state. Experimental Example 4 As shown in Table 5, the rubber composition No. 1 in Table 1 was used. 2 (EPD
M) and No. 3 (SBR-NR) for a combination of rubber compositions containing different types of raw rubber components, both unvulcanized, one unvulcanized, the other vulcanized and both vulcanized rubber Liquid paraffin on the surface of the material
Then, a paste obtained by mixing ultra- high molecular weight polyethylene powder was applied thereto, and then laminated. The resultant was heated and fused and integrated. The adhesion of the obtained rubber-rubber composite was evaluated, and the results are shown in Table 5.

[0029] From Table 5, it can be seen that the raw rubber component having a small γc value (EPDM = 2
8mN / m) and a raw rubber component (SBR =
33 mN / m, NR = 31 mN / m), when a rubber composition containing different kinds of raw rubber components is combined, γc
When the rubber material composed of the rubber composition containing the raw rubber component having a large value is vulcanized, the adhesiveness is maintained regardless of the vulcanized state of the rubber material composed of the rubber composition containing the raw rubber component having a small γc value. It turns out that is getting worse.

[0030]

As described above, according to the present invention, a rubber composition containing the same or different raw rubber components having a specific critical surface tension γc using ultra-high molecular weight polyethylene powder as an adhesive is provided. By using, in any case containing the same type of raw rubber component and different type of raw rubber component, between unvulcanized rubber materials, one is an unvulcanized rubber material and the other is a vulcanized rubber material. between or between vulcanized rubber material with each other, Ru can der be integrally joined, respectively. Also, the selection criteria for the rubber material to be bonded are
Adopt failure due to critical surface tension γc
Can be prevented. In addition, the following effects can be obtained.

Since it is an ultrahigh molecular weight polyethylene powder, even if the rubber material has a complicated shape or is preformed in advance, it can be bonded, and a wide variety of rubber products can be manufactured. Further, due to the excellent adhesiveness, a rubber / rubber adhesive composite having high adhesive strength and excellent durability can be manufactured. Ultra-high molecular weight polyethylene powder forms a film-like adhesive layer that prevents the diffusion and transfer of compounding chemicals between rubber materials after bonding, so vulcanization properties such as co-vulcanization properties between rubber materials and vulcanization temperature Adhesion can be performed regardless of vulcanization conditions and the presence or absence of vulcanization.

The film-like adhesive layer serves as a reinforcing material due to its excellent strength, high tensile modulus, and the like, and improves strength and dimensional stability. Further, since the film-like adhesive layer is thin and easily bent, it does not adversely affect the flexibility of the rubber-rubber composite. Therefore, the rubber-rubber adhesive composite obtained by the method of the present invention improves the strength and durability of tires, conveyor belts, hoses, lining products and other rubber products, and has a complicated shape. Are also readily applicable and extremely useful.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B29K 21:00 23:00 105: 24 B29L 9:00 C08L 21:00

Claims (4)

(57) [Claims] [Claim 1] and the critical surface tension γc is 25 to 35 mN / m 2 <br/> each rubber material unvulcanized rubber composition containing a raw rubber component of the same type, these rubber materials A rubber / rubber adhesive composite in which, after forming a laminate with an ultra-high molecular weight polyethylene powder interposed therebetween, the laminate is heated to a temperature equal to or higher than the melting temperature of the ultra-high molecular weight polyethylene powder and fused and integrated. Manufacturing method. 2. Two rubber compositions each containing the same kind of raw rubber component having a critical surface tension γc of 25 to 32 mN / m are used as rubber materials, and at least one of these rubber materials is used. After using a vulcanized rubber material and forming a laminate by interposing ultrahigh molecular weight polyethylene powder between these rubber materials, the laminate is heated to a temperature equal to or higher than the melting temperature of the ultrahigh molecular weight polyethylene powder. Method for producing a rubber-rubber bonded composite that is fused and integrated. 3. A rubber material comprising at least two types of rubber compositions each containing a different kind of raw rubber component having a critical surface tension γc of 25 to 30 millinewton / meter, and at least two of these rubber materials are used. An unvulcanized rubber material, a combination of an unvulcanized rubber material and a vulcanized rubber material, or a vulcanized rubber material, and an ultra-high molecular weight polyethylene powder is interposed between these rubber materials to form a laminate. After forming, the laminate is heated to a temperature equal to or higher than the melting temperature of the ultra-high molecular weight polyethylene powder and fused and integrated to produce a rubber-rubber bonded composite. 4. One is an unvulcanized rubber material comprising a rubber composition containing a raw rubber component having a critical surface tension γc of 30 to 35 millinewton / meter, and the other is a critical surface tension γc of 25 to 35 mN / m. An unvulcanized rubber material or a vulcanized rubber material composed of a rubber composition containing a raw rubber component of 30 millinewtons / meter, and laminated with an ultra-high molecular weight polyethylene powder interposed between these rubber materials A method for producing a rubber-rubber composite, in which after forming a body, the laminate is heated to a temperature equal to or higher than the melting temperature of the ultrahigh molecular weight polyethylene powder and fused and integrated.