JPH09295379A - Rubber laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber laminated with high strength and wear resistance by firmly adhering a hydrogenated NBR (acrylonitrile conjugate diene copolymer rubber) composition to a general-purpose rubber. SOLUTION: A sulfur vulcanizable diene rubber composition B is adhered by vulcanization to a rubber composition A containing a hydrogenated acrylonitrile-conjugate diene copolymer rubber and an organic peroxide through a rubber composition consisting of an aromatic petroresin with an average molecular weight of 300-1500, a softening point of 50-160 deg.C and an iodine value of at least, 5g/100g blended for a total of 100 pts.wt. of the rubber containing polybutadiene(BR) with at least, 25wt.% of 1,2-vinyl bonded amount of the butadiene part and/or a conjugate diene-aromatic vinyl copolymer rubber, and an acrylonitrile-butadiene copolymer rubber(NBR).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber laminate,
More specifically, the adhesiveness between an organic peroxide-crosslinkable hydrogenated acrylonitrile-conjugated diene copolymer rubber (hereinafter simply referred to as hydrogenated NBR) having excellent breaking strength and abrasion resistance and a general-purpose diene rubber is improved. It relates to a rubber laminate.
This rubber laminate is suitable for use as a tire member, and also as a conveyor belt.

[0002]

2. Description of the Related Art Hydrogenated acrylonitrile-butadiene copolymer rubber (hydrogenated NBR) compositions containing methacrylic acid, zinc oxide and organic peroxide are excellent in extremely high breaking strength when crosslinked with organic peroxide. Although it exhibits high strength, high elastic modulus, and excellent abrasion resistance, this rubber composition has a problem of poor adhesion to general-purpose rubber (diene rubber).

Although there are some proposals for solving such a problem, a solution suitable for practical use has not yet been reached. For example, JP-A-5-185805 discloses a hydrogenated N containing methacrylic acid, zinc oxide and an organic peroxide.
A bead filler, an inner liner, a belt layer peripheral portion or a tread portion made of a BR rubber composition is used for a general-purpose rubber (for example, natural rubber, styrene-butadiene copolymer rubber, polybutadiene rubber, etc.) which is a tire constituent body, and a butyl rubber layer (hydrogen). A technique for adhering via an adhesive layer of two layers of an added NBR layer side) and an ultrahigh molecular weight polyethylene sheet layer (diene rubber side) is disclosed, but this method requires two adhesive layers. Therefore, there is a problem that the manufacturing process becomes complicated.

Further, in Japanese Unexamined Patent Publication (Kokai) No. 5-179062, a rubber composition containing a carboxyl group-modified liquid isoprene rubber and a sulfur-containing silane coupling agent is added to NBR and / or SBR based on NBR or NBR / SBR. It is disclosed that both the rubber composition for the cover rubber layer and the woven fabric made of nylon or polyester exhibit good vulcanization adhesion and exhibit good oil resistance. In this publication, the hydrogenated NBR rubber is disclosed. No mention is made of the adhesion to the composition.

[0005]

Accordingly, the present invention solves the problem of poor adhesion between the hydrogenated NBR rubber composition and the general-purpose diene rubber as described above, and exhibits excellent strength and abrasion resistance. An object of the present invention is to provide a rubber laminate capable of using the hydrogenated NBR rubber composition in rubber products such as tires.

[0006]

According to the present invention, as shown in FIG. 1, a rubber composition (HNBR) containing (A) hydrogenated acrylonitrile-conjugated diene copolymer rubber and an organic peroxide, The (B) sulfur-vulcanizable diene rubber composition is replaced with (C) at least the (a) butadiene moiety 1,2-
Polybutadiene having a vinyl bond content of 25% by weight or more (B
R) and / or a conjugated diene-aromatic vinyl copolymer rubber and (b) acrylonitrile-butadiene copolymer rubber (NBR) in 100 parts by weight of rubber in total, (c)
Average molecular weight 300 to 1500, softening point 50 to 160 ° C.,
Provided is a rubber laminate which is vulcanized and adhered via a rubber composition containing an aromatic petroleum resin having an iodine value of 5 g / 100 g or more.

According to a preferred embodiment of the present invention, there is also provided a rubber laminate in which the rubber composition (A) further contains a zinc salt of methacrylic acid and / or a derivative thereof.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The hydrogenated acrylonitrile-conjugated diene copolymer rubber (hydrogenated NBR rubber) used in the present invention is a conventionally known synthetic rubber crosslinked with an organic peroxide. Organic peroxides in the added NBR rubber, and preferably methacrylic acid and / or its derivatives (eg (meth) acrylic acid, alkyl (meth)).
A rubber composition (A) is prepared by blending a zinc salt of acrylate, alkoxyalkyl (meth) acrylate, cyanoalkyl (meth) acrylate, or the like. The zinc salt of methacrylic acid and / or its derivative may be prepared by separately blending methacrylic acid and / or its derivative and a zinc compound (eg, zinc oxide, zinc carbonate, etc.) into the composition.

The compounding ratio of each component in the rubber composition (A) is not particularly limited, but the amount of methacrylic acid and / or its derivative used is 100 parts by weight of hydrogenated NBR rubber.
10 to 70 parts by weight, zinc compound is hydrogenated NBR rubber 1
It is preferable that the rubber composition (A) has a tensile strength and a tear strength of 5 to 80 parts by weight relative to 00 parts by weight. The organic peroxide can be any conventionally known one, and any organic peroxide can be used as long as it can crosslink the hydrogenated NBR rubber.
Examples of such organic peroxides include, for example, dicumyl peroxide, di-t-butyl peroxide, t-
Butyl cumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxyisopropyl) hexyne-3,2,5-dimethyl-
2,5-di (t-butylperoxy) hexane, 2,5
-Dimethyl-2,5-mono (t-butylperoxy)-
Hexane, α, α′-bis (t-butylperoxy-m
-Isopropyl) benzene etc. may be mentioned.
The amount of organic peroxide is preferably hydrogenated NB.
It is 0.2 to 10 parts by weight per 100 parts by weight of the R rubber, and it is desirable to appropriately determine the optimum amount according to the required physical property values.

As the sulfur-vulcanizable diene rubber composition (B) capable of being vulcanized with sulfur which constitutes the other layer of the rubber laminate of the present invention, any diene rubber which has been widely used in the past can be used. Examples thereof include natural rubber, polyisoprene rubber, various polybutadiene rubbers, and various styrene-butadiene copolymer rubbers, which are appropriately selected according to the desired use of the rubber laminate. Diene rubber composition (B)
In addition, sulfur, a vulcanization accelerator, and other general-purpose additives can be added to the diene rubber.

According to the invention, between the layer of the rubber composition (A) and the layer of the sulfur vulcanizable diene rubber (B), at least the (a) butadiene portion as the rubber composition (C) is present. The polybutadiene (BR) having a 1,2-vinyl bond content of 25% by weight or more and / or a conjugated diene-aromatic vinyl copolymer rubber and (b) an acrylonitrile-butadiene copolymer rubber (NBR), (c) Number average molecular weight 300-
1500, preferably 400-1400, softening point 50-
160 ° C., preferably 50 to 130 ° C., iodine value 5 g /
A strong adhesive force is obtained by interposing one adhesive layer of a rubber composition (C) containing 100 g or more, preferably 8 g / 100 g or more and an upper limit value of preferably 50 g / 100 g or less, with an aromatic petroleum resin. It is possible to obtain a rubber laminate having The 1,2-vinyl bond content in 100 parts by weight of rubber is 20% or more, especially 20 to 70%.
And the NBR amount is preferably 20 to 60 parts by weight. If the amount of vinyl in the rubber is too small, sufficient cross-linking adhesion with the hydrogenated NBR composition (A) cannot be obtained. Further, if the amount of NBR in the rubber is too small, the cross-linking adhesiveness with the hydrogenated NBR composition (A) may decrease, and conversely if it is too large, the cross-linking adhesiveness with the diene rubber composition (B) will decrease. There is a risk of

The rubber composition according to the present invention contains the component (C).
Polybutadiene (BR) blended as (a) and /
Or styrene-butadiene copolymer rubber (SBR) is
If the 1,2-vinyl bond content of the butadiene portion is 25% by weight or more, preferably 30% by weight or more, it can be obtained by any BR or SBR (emulsion polymerization method or solution polymerization method) which is generally used as a conventional rubber. SBR) are also included. In addition, SBR or BR 1,2-
When the vinyl bond content is less than 25% by weight, the upper limit of the content of (C) (a) (80 parts by weight, that is, the NBR (C)
Even at the lower limit (20 parts by weight) of the compounding amount of (b), it becomes impossible to set the amount of vinyl in 100 parts by weight of rubber to 20% or more.

The acrylonitrile-butadiene copolymer rubber (C) (b) is not particularly limited, but the amount of bound acrylonitrile is 16 to 40% by hydrogenation N.
It is preferable in terms of adhesiveness with the BR composition (A). Note that other rubber components may of course be blended as long as they are within the ranges that satisfy the vinyl amount and the NBR amount, and the blending ratio of these rubber components may be arbitrary.

The rubber composition (C) is preferably 15 to 15 parts by weight based on 100 parts by weight of the total amount of the rubber of the rubber composition (C).
As the aromatic petroleum resin (c) blended in 100 parts by weight, a resin which has been conventionally known to be used for rubber compounding applications can be used as described above. Examples of the aromatic petroleum resin include Fuccol resin FR-120 (trade name, manufactured by Sumikin Kako Co., Ltd.).

The rubber laminate according to the present invention can be produced by using any of the above compositions (A), (B) and (C) by any known method. More specifically, the adhesive composition (C) can be molded into a sheet shape and inserted between the layers of the compositions (A) and (B) for vulcanization adhesion, or the composition (C) can be used in an appropriate solvent. (For example, toluene, xylene,
It can be dissolved in ethyl acetate, methyl ethyl ketone, tetrahydrofuran, n-hexane, etc.) and applied between the layers of the compositions (A) and (B), followed by vulcanization adhesion after drying. The vulcanization conditions can be the same as conventional conditions.

In addition to the above-mentioned essential components, the rubber composition according to the present invention generally contains various additives such as reinforcing agents such as carbon black, antioxidants, fillers, softeners, plasticizers and the like for rubber. Additives can be blended and such blends can be vulcanized and manufactured by conventional methods. The amount of these additives may be a general amount.

[0017]

EXAMPLES The present invention will be further described with reference to the following examples, but it goes without saying that the scope of the present invention is not limited to these examples.

Examples 1 to 4 and Comparative Examples 1 to 5 A rubber laminate was prepared using the rubber compositions A, B and C having the following composition, and the adhesiveness was determined according to JIS K6256 (adhesion test method for vulcanized rubber). And the peeled state was observed.

The compositions of the rubber compositions A and B used and the peel strength between these layers are shown in Table I.

[0020]

[Table 1]

On the other hand, the composition of the adhesive rubber composition C is shown in Table II.

[0022]

[Table 2]

The rubber compositions A, B and C were compounded into a masterbatch by mixing raw materials other than the vulcanization accelerator and sulfur (or organic peroxide) in a closed mixer. The standard mixing time was 4 minutes and the discharge temperature was 130 ° C. An unvulcanized test rubber was prepared by adding the remaining compounding ingredients to the masterbatch with an open roll.

As shown in Table I, unvulcanized rubber material B,
Directly stacking unvulcanized hydrogenated NBR composition A, 1
Press vulcanization at 60 ℃ for 30 minutes, 150mm × 25mm
A rubber laminate vulcanized product of 6 mm was prepared.

The peel test between the layer of the composition A and the layer of the composition B of the rubber laminate obtained as described above was carried out, and the peel strength and the peeled state were observed. The results are shown in Table I above.

Further, a peeling test was conducted between the layer of the rubber composition A and the layer of the rubber composition C, and the peeling strength and the peeling state were observed. The results are shown in Table II above.

[0027]

As shown in the above Examples and Comparative Examples, according to the present invention, a hydrogenated acrylonitrile-butadiene rubber composition (A) cross-linked with an organic peroxide,
The diene rubber composition (B) that is crosslinked with sulfur has a 1,2-vinyl bond content of at least (a) butadiene of 3
Adhesive rubber composition (C) containing 0% by weight or more of polybutadiene (BR) and / or conjugated diene-aromatic vinyl copolymer rubber, (b) acrylonitrile-butadiene copolymer rubber (NBR) and aromatic petroleum resin. ) Hydrogenated NB by vulcanization and adhesion via
The R composition and the general-purpose diene-based rubber can be firmly adhered with a single layer of adhesive rubber, and the hydrogenated NBR having excellent strength and abrasion resistance can be used for each member of the tire and the like.

[Brief description of drawings]

FIG. 1 is a drawing showing a structure of a laminated body of the present invention.

Claims (3)

[Claims] 1. A rubber composition containing (A) a hydrogenated acrylonitrile-conjugated diene copolymer rubber and an organic peroxide, (B) a sulfur vulcanizable diene rubber composition, and (C).
At least (a) polybutadiene (BR) having a 1,2-vinyl bond content of 25% by weight or more in the butadiene portion and /
Or a conjugated diene-aromatic vinyl copolymer rubber and (b) an acrylonitrile-butadiene copolymer rubber (N
(C) an average molecular weight of 300 to 1500, a softening point of 50 to 160 ° C., and an aromatic petroleum resin having an iodine value of 5 g / 100 g or more and vulcanized through a rubber composition. A rubber laminate made by bonding. 2. The rubber laminate according to claim 1, wherein the rubber composition (A) further contains a zinc salt of methacrylic acid and / or a derivative thereof. 3. The total amount of rubber in the rubber composition (C) is 100.
The amount of 1,2-vinyl bond in 20 parts by weight is 20 to 70%, the acrylonitrile-butadiene copolymer (C) (b) is 20 to 60 parts by weight in 100 parts by weight of rubber, and the aroma is Group petroleum resin (C) (c) 15 ~
The rubber laminate according to claim 1 or 2, which is blended with 100 parts by weight.