JP3116247B2 - Rubber / rubber bonded composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition containing a hydrogenated acrylonitrile-butadiene copolymer rubber, methacrylic acid, zinc oxide and an organic peroxide, and a rubber composition containing a specific general-purpose rubber. And a rubber-rubber composite.

[0002]

2. Description of the Related Art A rubber composition containing hydrogenated acrylonitrile / butadiene copolymer rubber, methacrylic acid, zinc oxide and an organic peroxide (hereinafter referred to as hydrogenated NBR rubber composition A) is vulcanized and cured. It forms a rubber material with high strength and hardness, remarkably excellent in heat resistance and oil resistance, and having many features. For this reason, if this rubber material can be directly bonded to a general-purpose rubber material, the high-hardness and high-strength of the hydrogenated NBR rubber composition will make the general-purpose rubber layer thinner, light weight, high strength, and high heat resistance. Rubber products such as tires, hoses and belts having excellent oil resistance can be obtained. In addition, since the hydrogenated NBR rubber composition has high strength by itself without blending carbon black, it can be provided with any color and coloring, and has an advantage that its appearance can be beautiful. However, since the hydrogenated NBR rubber composition has poor adhesion to general-purpose rubber, it was practically impossible to obtain a product of such a rubber-rubber bonded composite.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to bond a general-purpose rubber to a hydrogenated NBR rubber composition containing the above hydrogenated NBR rubber, methacrylic acid, zinc oxide and an organic peroxide. Accordingly, an object of the present invention is to provide a rubber-rubber bonded composite which is lightweight, has high strength, high hardness, and has excellent heat resistance and oil resistance.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a hydrogenated NBR rubber, a hydrogenated NBR rubber composition A containing methacrylic acid, zinc oxide and an organic peroxide, and a critical surface tension. An ultra-high molecular weight polyethylene sheet prepared by cutting a rubber composition (hereinafter, referred to as a general-purpose rubber composition) B containing a raw rubber having a γc of 26 to 29 millinewton / meter (hereinafter abbreviated as mN / m). (Hereinafter referred to as an ultra-high molecular weight PE sheet) or an ultra-high molecular weight polyethylene powder C and bonded and integrated.

In the present invention, the ultrahigh molecular weight PE sheet or powder C has excellent adhesion to the hydrogenated NBR rubber composition A and has a γc of 26 to 29 mN / m.
Has good adhesion to the general-purpose composition B. For this reason, the hydrogenated NBR rubber composition A and γc are 26 to 2
A high strength, high hardness based on the hydrogenated NBR rubber composition A is obtained by interposing an ultra-high molecular weight PE sheet or powder C to bond and integrate with the general-purpose rubber composition B in the range of 9 mN / m. A lightweight rubber-rubber adhesive composite having excellent heat resistance and oil resistance and having characteristics that can be given any color and color can be obtained.

In the present invention, the critical surface tension γc is
On August 20, 1978, published in Maruzen Co., Ltd., "Chemical Handbook" Basic Edition II (3rd printing), p.
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 γc corresponding to 1. However, the critical surface tension γc of the raw rubber as defined in the present invention means a value measured similarly using a rubber sample obtained by flattening the raw rubber for which γc is to be measured by a hot press instead of the above solid. .

The hydrogenated NBR rubber composition A used in the present invention has an ethylene unsaturated nitrile unit of 10 to 10 units.
60 parts by weight, methacrylic acid is 20 to 60 parts by weight, zinc oxide is 10 to 60 parts by weight, and organic peroxide is 0.5 to 100 parts by weight of hydrogenated NBR containing not more than 30 parts by weight of a conjugated diene unit. There is a composition formulated with 20 parts by weight.

The general-purpose rubber composition B used in the present invention
It is necessary to select and blend a raw rubber having a critical surface tension γc in the range of 26 to 29 mN / m, and there is no particular limitation as long as it has a critical surface tension γc in the above range. If the critical surface tension γc of the raw rubber is not in the above range, good adhesion to the ultrahigh molecular weight PE sheet or powder C cannot be obtained. In addition, such a general-purpose rubber composition B may include a vulcanizing agent such as sulfur, a reinforcing agent such as carbon black, an antioxidant,
A predetermined amount of a vulcanization accelerator and other rubber chemicals can be blended.

In the present invention, the ultra-high molecular weight PE sheet produced by the shaving method refers to an ultra-high molecular weight polyethylene powder which is heated and pressurized and sintered to produce a columnar molded product, and this molded product is formed into a peripheral shape. It refers to a sheet or film cut in a thin direction. The ultrahigh molecular weight PE sheet or powder C used in the present invention is desirably made of polyethylene having a molecular weight of 1,000,000 or more.
When the molecular weight is 1,000,000 or more, hydrogenated NB
The adhesiveness between the R rubber composition A and the general-purpose rubber composition B can be further improved. The ultrahigh molecular weight PE sheet preferably has a thickness in the range of 10 to 200 μm. By setting the thickness to 10 μm or more, the tensile strength and the elastic modulus can be increased, and a reinforcing effect can be provided. On the other hand, when the thickness is 200 μm or less, the flexibility of the bonded portion can be secured. Also, ultra high molecular weight PE
The powder preferably has an average particle size of 50 to 300 μm.
By setting the average particle diameter to 50 μm or more, hydrogenated N
The adhesion between the BR rubber composition A and the general-purpose rubber composition B can be further improved. Further, when the thickness is 300 μm or less, the rubber material can be evenly and uniformly interposed between the rubber materials, and a thin adhesive layer can be formed. This powder may be sprayed on the bonding surface as it is, or may be applied as a paste mixed with oil such as liquid paraffin.

[0010] Such a rubber-rubber adhesive composite of the present invention can be produced as follows. First, an unvulcanized hydrogenated NBR rubber composition A and a general-purpose rubber composition B are each preformed to form a rubber material having an arbitrary stackable shape such as a sheet or a plate.
These rubber materials are metal cords such as steel cords,
It may be reinforced with a cord made of various organic fibers such as nylon, polyester, and aramid. An ultra-high molecular weight PE sheet or powder C is interposed between the preformed rubber materials and heated under a press to obtain an ultra-high molecular weight P
E film or powder C is melted and hydrogenated N
By vulcanizing the BR rubber composition A and the general-purpose rubber composition B, they can be bonded and integrated to form a rubber-rubber bonded composite.

[0011]

EXAMPLES Four general-purpose rubber compositions B-1 (rubber component NR, γc = 31 mN /
m), B-2 (rubber component IIR, γc = 27 mN /
m), B-3 (rubber component EPDM, γc = 28 mN /
m) and B-4 (rubber component SBR, γc = 33 mN /
m) was prepared. From each of these general-purpose rubber compositions, a sheet-like unvulcanized rubber material of 150 mm × 50 mm × 2.5 mm was formed.

As the hydrogenated NBR rubber composition A, ZSC-2295, 85% by weight manufactured by Zeon Corporation and ZETPOL-2020 manufactured by Zeon Corporation
(Hydrogenated NBR) was added and mixed with a roll by 15% by weight, and 1.5 parts by weight of an antioxidant (“Nowgard 445”) was added to 100 parts by weight of this mixture. “Parcadox 14/40”
Using a composition obtained by adding and mixing 5 parts by weight of (1,3-bis-tert-butylperoxy-isopropyl-benzene) similarly by a roll, 150 mm × 50 mm
It was formed into a sheet material of × 2.5 mm.

Further, a 50 μm-thick film-like ultrahigh molecular weight PE sheet C made of polyethylene having a molecular weight of about 5,000,000 and prepared by a shaving method was prepared. The hydrogenated NBR rubber composition A and the general-purpose rubber composition B-1, 2, 2
3 and 4 were heated at 170 ° C. for 20 minutes under a pressure of 20 kg / cm ^{2 with} the ultra-high molecular weight PE sheet C interposed therebetween to melt the ultra-high molecular weight PE sheet C and at the same time the hydrogenated NBR-containing rubber composition A and general-purpose rubber composition B-
Each of 1, 2, 3, and 4 was vulcanized to obtain a rubber-rubber bonded composite, A / C / B-1 (Comparative Example 1), A / C / B-2 (Example 1), and A / C / B-3 (Example 2), A / C / B-
4 (Comparative Example 2) was produced.

[0014]

* 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.

The adhesion of the obtained rubber-rubber composite was evaluated by the following method. The results are shown in Table 2. 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 the interface separation did not occur, 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 a razor was used to cut a sheet near the interface. The peel test was repeated five times, and the case where any one of the sheets adhered so strongly that cohesive failure occurred inside was evaluated as good (○).

[0017] From Table 2, the critical surface tension γc of Examples 1 and 2 is 25 to 3
A hydrogenated NBR rubber composition A is bonded to a general-purpose rubber composition B-2 or B-3 containing IIR and EPDM as rubber components in a range of 0 mN / m via an ultra-high molecular weight PE sheet C. Comparative Examples 1 and 2
Could not be adhered to rubber compositions B-1 and B-4 containing NR and SBR whose γc was out of the above range.

[0018]

According to the present invention, a rubber-rubber composite in which a hydrogenated NBR rubber composition A and a general-purpose rubber composition B are directly bonded and integrated by using an ultrahigh molecular weight PE sheet or powder C. Can be the body. Therefore,
Excellent properties such as high strength, high hardness, heat resistance and oil resistance of the hydrogenated NBR rubber composition A can be imparted to the general-purpose rubber composition B, while reducing the amount of the general-purpose rubber composition B used. High-strength, high-hardness lightweight tires, hoses,
Rubber products such as belts can be obtained. Moreover, by utilizing the fact that the hydrogenated NBR rubber composition A is colorless, it is possible to impart an arbitrary color and coloring to make the appearance beautiful.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 5/12

Claims (1)

(57) [Claims] 1. A rubber composition A containing a hydrogenated acrylonitrile-butadiene copolymer rubber, methacrylic acid, zinc oxide and an organic peroxide, and a critical surface tension γc of 26.
A rubber-rubber composite in which a rubber composition B containing a raw rubber of up to 29 millinewtons / meter is bonded and integrated with an ultrahigh molecular weight polyethylene sheet or ultrahigh molecular weight polyethylene powder C prepared by a shaving method.