JPH0570632A - Rubber composition and vulcanized rubber composition - Google Patents

Abstract

(57) [Summary] [Structure] 20 parts by weight of isoprene-isobutylene copolymer, 100 parts by weight of ethylene-propylene-5-ethylidene-2-norbornene copolymer and 1.6 parts of organic peroxide.
A rubber composition comprising 1 part by weight. [Effect] A vulcanized rubber composition having a low hardness can be obtained without "slip" during kneading.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rubber composition and a vulcanized rubber composition. According to the present invention, it is possible to obtain a soft vulcanized rubber composition having a low hardness, that is, a vulcanized rubber composition having a low hardness, and without a problem of so-called "slip" during kneading, in an extremely short time. It enables efficient kneading operation.

[0002]

2. Description of the Related Art Conventionally, as a method for obtaining a low hardness rubber composition, a method has been known in which a large amount of a softening agent such as process oil is contained in a rubber component. According to this method, a large amount of a softening agent such as process oil is added to the rubber component and kneading is performed using a kneader having a rotor or the like. At this time, the rubber composition containing a large amount of the softening agent is It is extremely slippery, and a large amount of softening agent adheres to the rotor of the kneading machine, which causes the rotor and the rubber component to slide together, resulting in these so-called "slip" problems, and as a result, sufficient kneading is difficult and kneading is difficult. It has a drawback that it takes a very long time.

[0003]

In view of the present situation, the problem to be solved by the present invention is to obtain a soft vulcanized rubber composition having a low hardness, that is, a vulcanized rubber composition having a low hardness, and An object of the present invention is to provide a method capable of performing an efficient kneading operation in an extremely short time without the problem of so-called “slip” during kneading.

[0004]

The present inventors have arrived at the present invention as a result of intensive studies to solve the above problems. That is, of the present invention, the first invention is a rubber composition comprising the following components (A) to (C):
Weight ratio of component (A) / component (B) is 5/95 to 40/6
And a rubber composition having a weight ratio of component (C) / (component (A) + component (B)) of 0.5 / 100 to 10/100. (A) component: butyl rubber and / or solid polyisobutylene (B) component: rubber vulcanizable with organic peroxide (C) component: organic peroxide

The second aspect of the present invention is a rubber composition comprising the above component (C) and the following component (D), wherein the weight ratio of component (C) / component (D) is: 0.5 / 1
The present invention relates to a rubber composition of 00 to 10/100. Component (D): Partial vulcanization obtained by kneading 100 parts by weight of the total amount of the above components (A) and (B) and 0.5 to 3 parts by weight of organic peroxide at 120 to 190 ° C. A partially vulcanized rubber composition, wherein the weight ratio of component (A) / component (B) is 5/95 to 40/60.

Further, the third invention of the present invention relates to a vulcanized rubber composition obtained by vulcanizing the rubber composition of the first invention or the second invention.

The details will be described below. The component (A) of the present invention is butyl rubber and / or solid polyisobutylene. That is, polyisobutylene is limited to solid ones. When liquid polyisobutylene is used, the problem of so-called "slip" cannot be solved, and thus the effect of the present invention that kneading can be performed in a short time is not exhibited. The butyl rubber refers to isoprene-isobutylene copolymer rubber or isoprene-isobutylene copolymer rubber modified with chlorine or bromine.

The component (B) of the present invention is a rubber which can be vulcanized by an organic peroxide, and is a rubber other than a rubber which is decomposed without being vulcanized by an organic peroxide, such as butyl rubber and polyisobutyle. Is. Specific examples of such rubber include ethylene-α / olefin copolymer rubber,
Examples thereof include styrene-butadiene copolymer rubber, isoprene rubber, butadiene rubber, nitrile-butadiene rubber, chloroprene rubber and natural rubber. Note that oil-extended rubber may be used. Further, the ethylene-α-olefin copolymer rubber refers to a copolymer of ethylene and α-olefin or a copolymer of ethylene, α-olefin and a non-conjugated diene, and α-olefin includes propylene and 1-butene. , 1-pentene, 1-hexene and the like, and non-conjugated dienes include 5-methylene-2-norbornene,
Examples include 5-ethylidene-2-norbornene, dicyclopentadiene, 1,4-hexadiene and the like.

The component (C) of the present invention is an organic peroxide, and examples thereof include diacyl peroxide, dialkyl peroxide, peroxy ester, peroxy ketal and the like. These may be used alone or in combination. Good. Specific examples of the organic peroxide include benzoyl peroxide, 1,1-di-t-butylperoxy-3,
Examples include 3,5-trimethylcyclohexane, di-t-butylperoxydiisopropylbenzene, dicumyl peroxide, and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane.

The first aspect of the present invention is a rubber composition comprising components (A) to (C), wherein the weight ratio of component (A) / component (B) is 5/95 to 40. / 60, preferably 10/90 to 40/60, and the component (C) /
The weight ratio of ((A) component + (B) component) is 0.5 / 100.
-10/100, preferably 2/100 to 6/100.

In the ratio of the component (A) and the component (B),
When the amount of the component (A) is too small, the resulting vulcanized rubber composition has a decreased hardness, that is, the degree of softening is not sufficient. On the other hand, when the amount of the component (B) is too small, the vulcanized rubber composition has insufficient tensile strength, and the surface becomes tacky, which is inconvenient.

In the ratio of (component (A) + component (B)) and component (C), if the component (C) is too small, the tensile strength of the vulcanized composition obtained will decrease, while When the component (C) is excessive, the tensile strength is lowered and the hardness is not sufficiently lowered. In addition, when the oil-extended rubber is used as the component (B), the amount of the component (B) used is based on the amount of only the rubber component excluding the amount of the extender oil.

In order to obtain the above rubber composition, for example, predetermined amounts of the components (A) to (C) are compared at 40 to 110 ° C. by using an open roll or a closed kneader such as a Banbury mixer. It suffices to knead in an extremely low temperature range.

The second aspect of the present invention is a rubber composition comprising the above component (C) and the following component (D), wherein the weight ratio of component (C) / component (D) is 0.1. 5/10
0-10 / 100, preferably 2 / 100-6 / 100
The present invention relates to a rubber composition. Component (D): Partial vulcanization obtained by kneading 100 parts by weight of the total amount of the above components (A) and (B) and 0.5 to 3 parts by weight of organic peroxide at 120 to 190 ° C. A rubber composition having a weight ratio of component (A) / component (B) of 5/95 to 40/60, preferably 10/90 to 4
0/60 partially vulcanized rubber composition

In the ratio of the component (C) and the component (D),
When the amount of the component (C) is too small, the tensile strength of the obtained vulcanized composition is lowered, while when the amount of the component (C) is too large, the tensile strength is lowered and the hardness is not sufficiently lowered. .. In the ratio of the component (A) and the component (B) in the component (D), when the amount of the component (A) is too small, the hardness of the obtained vulcanized rubber composition decreases, that is, the degree of softening is insufficient. On the other hand, when the amount of the component (B) is too small, the vulcanized rubber composition has insufficient tensile strength, and the surface becomes tacky, which is inconvenient. When the amount of the organic peroxide used in obtaining the component (D) is too small or when the kneading temperature is too low, the extruded product is likely to be deformed during vulcanization, while when the amount is too large or the kneading temperature is too high. If is too high, the extrusion processability becomes poor.

Specific examples of the organic peroxide used for obtaining the component (D) include those similar to the organic peroxide used as the component (C). However,
The organic peroxide used for obtaining the component (D) is
It may be the same as or different from the organic peroxide used as the component (C).

To obtain the component (D), each component may be kneaded under the above conditions using an open roll or a closed kneader such as a Banbury mixer. Thus, the rubber composition of the first invention or the rubber composition of the second invention can be obtained, but the rubber composition of the present invention contains, in addition to the above components, a range that does not cause "slip" during kneading. At the inner,
A softening agent such as oil and other additives may be included.

The rubber composition of the first invention or the rubber composition of the second invention is made into a vulcanized rubber composition as a final product by the following method, for example. That is, for the rubber composition of the present invention, if necessary, a co-crosslinking agent such as ethylene dimethyl methacrylate, trimethylpropane trimethacrylate, triallyl isocyanurate, N, N'-m-phenylene bismaleimide, rubber industry A filler, a softener, an additive, an antioxidant, etc. which are usually used in are mixed and kneaded, and after being subjected to steps such as pressing, injection molding, extrusion and vulcanization, the final product is a vulcanized rubber composition. It In addition,
Vulcanization is usually performed at a temperature of 140 to 200 ° C. for 2 to 60 minutes.

The vulcanized rubber composition obtained by the present invention described above is an extremely soft low-hardness rubber composition, and does not cause "slip" at the time of kneading during processing, unlike the conventional method. Therefore, kneading can be performed within an extremely short time. Although the mechanism of action by which the method of the present invention exhibits such excellent effects is not always clear, it can be estimated as follows, for example. However, this estimation does not limit the scope of the present invention. By kneading the rubber composition of the present invention in a relatively high temperature range of 120 to 190 ° C. and further vulcanizing at 140 to 200 ° C., the butyl rubber or the polyisobutylene as the component (A) is decomposed to have a low molecular weight. It is considered that the low molecular weight molecular chain acts as a lubricant or a softening agent, and thus an extremely soft low-softness rubber composition can be obtained. Then, in the previous stage, (A) component and (B)
At the time of kneading the components with a temperature range of, for example, 40 to 190 ° C., the component (A) is still in a solid state which does not decompose, so that the problem of slippage at the time of kneading does not occur and the component (A) The components (B) and (B) are sufficiently mixed in a short time.

The rubber composition obtained in the present invention is used in a wide range of fields, especially low-softness, such as various office equipment rolls (paper feed rolls, etc.), automobile seal members (door seals, trunk seals, etc.), various types. It can be used as a cushioning material or the like.

[0021]

EXAMPLES The present invention will be described with reference to Examples and Comparative Examples. Example 1 The compounding ingredients shown in the column 1 of Table 1 are kneaded at 120 to 130 ° C. using a 1.5 liter Banbury mixer,
Furthermore, the compounding agent shown in the column of compounding 2 was added, and the mixture was kneaded at 40 to 60 ° C. using an open roll to obtain a rubber composition. No "slip" occurred during any kneading, and kneading was completed within an extremely short time (within 5 minutes). Moreover, the obtained composition was vulcanized at 170 ° C. for 10 minutes to obtain a vulcanized rubber composition. Regarding the vulcanized rubber composition, JIS K 63
Vulcanization physical properties were measured in accordance with No. 01. The results are shown in Table 1.

Examples 2 to 4 The same procedure as in Example 1 was carried out except that the amount or kind of the component (A) was changed. The conditions and results are shown in Table 1. Examples 5 to 7 Example 1 except that the organic peroxide was used in the formulation 1 and the kneading temperature of the formulation 1 was 130 to 140 ° C.
I went the same way. The conditions and results are shown in Table 2.

Comparative Example 1 The procedure was carried out according to the conventional method of adding a large amount of oil without using the component (A). As a result, “slip” occurred during kneading, which required a long time (8 minutes or more) for kneading. The kneading time of 8 minutes or more including "sliding" generally corresponds to the kneading time of 30 minutes or more on an industrial scale. The conditions and results are shown in Table 3. Comparative Examples 2 to 5 Sulfur was used instead of using the component (C) (organic peroxide) in Formulation 2. As a result, the decrease in hardness of the vulcanized product was insufficient. The conditions and results are shown in Table 3.

[0024]

[Table 1] ─────────────────────────────── Actual Example 1 2 3 4 Formulation 1 (parts by weight) (A ) Component * 1 IIR ← ← PIB 20 40 60 20 (B) Component * 2 100 ← ← ← (A) / (B) wt ratio 17/83 29/71 38/62 17/83 Oil * 3 50 ← ← ← Heavy calcium carbonate 130 ← ← ← ZnO 5 ← ← ← Stearic acid 1 ← ← ← PEG-4000 * 4 1 ← ← 0 Si69 * 5 0 ← ← 0.5 Antiaging agent * 6 0 ← ← 1 Formulation 2 (parts by weight) Component (C) * 7 2.7 ← ← 5.4 (C) / ((A) / (B)) wt ratio 2.25 / 100 1.93 / 100 1.69 / 100 4.5 / 100 Anti-aging agent * 6 1 ← ← 0 Cross-linking aid * 8 1 ← ← 1 Evaluation No slippage during kneading ← ← ← Vulcanization properties Tensile strength Kg / cm ² 48 39 35 28 Elongation% 1000 960 930 730 Hardness JIS-A 19 19 17 23 ────────── ──────────────────────

[0025]

[Table 2]

[0026]

[Table 3] ─────────────────────────────────── Comparative Example 1 2 3 4 5 Formula 1 ( (Parts by weight) (A) component * 1-IIR ← ← ← 0 20 60 20 60 (B) component * 2 100 ← ← ← ← (A) / (B) wt ratio-17/83 38/62 17/83 38 / 62 Oil * 3 90 50 ← ← ← Heavy calcium carbonate 130 ← ← ← ← ZnO 5 ← ← ← ← Stearic acid 1 ← ← ← ← PEG-4000 * 4 1 ← ← ← ← PO * 9 0 ← ← 1.6 ← PO / ((A) / (B)) wt ratio-← ← 1.3 / 100 1.0 / 100 Blend 2 (parts by weight) Sulfur 1 ← ← ← ← Vulcanization accelerator * 10 5 ← ← ← ← Evaluation Sliding during kneading Yes No ← ← ← Vulcanization properties Tensile strength Kg / cm ² 112 128 86 128 86 Elongation% 900 840 790 840 790 Hardness JIS-A 23 27 25 27 25 ─────────────── ─────────────────────

* 1 IIR: isoprene-isobutylene copolymer (Butyl-268 manufactured by Nippon Butyl Co., Ltd.) PIB: solid polyisobutylene (manufactured by Exxon Chemical Co.)
Vistanex MML-80) * 2 Oil-extended ethylene-propylene-5-ethylidene-2-
Norbornene copolymer (Supreme 67 manufactured by Sumitomo Chemical Co., Ltd.
0F rubber component / extending oil weight ratio = 1/1) 100 parts by weight of component (B) shown in the table is the weight of only the rubber component excluding the extending oil weight. * 3 Idemitsu Kosan Process Oil PW-90 * 4 Polyethylene glycol Average molecular weight 4000 * 5 Desilane Co., Ltd. Silane coupling agent * 6 2-Mercaptobenzimidazole * 7 Dicumyl peroxide * 8 In Example 4, N, N'-m-phenylene bismaleimide was used. In other examples, a polyfunctional methacrylate monomer (High Cross M manufactured by Seiko Chemical Co., Ltd.) was used. * 9 Organic peroxide peroxide 3M manufactured by NOF Corporation
(1,1-bis (t-butylperoxy) 3,3,5-
Trimethylcyclohexane) * 10 Sumitomo Chemical Co., Ltd. vulcanization accelerator Soxinol BZ
(2.0 parts by weight) + TT (0.5 parts by weight) + TRA
(0.5 parts by weight) + M (2.0 parts by weight)

[0028]

As described above, according to the present invention, a soft vulcanized rubber composition having a low hardness, that is, a vulcanized rubber composition having a low hardness can be obtained, and the problem of so-called "slip" during kneading is solved. It was possible to provide a method capable of performing an efficient kneading operation in an extremely short time without involving it.

Claims (3)

[Claims] 1. A rubber composition comprising the following components (A) to (C), wherein the weight ratio of component (A) / component (B) is 5:
/ 95 to 40/60, and the weight ratio of component (C) / (component (A) + component (B)) is 0.5 / 100 to 10/10.
A rubber composition of 0. (A) component: butyl rubber and / or solid polyisobutylene (B) component: rubber vulcanizable with organic peroxide (C) component: organic peroxide 2. The component (C) according to claim 1 and the following (D):
A rubber composition comprising components, which is (C) component / (D)
A rubber composition in which the weight ratio of the components is 0.5 / 100 to 10/100. Component (D): A total of 100 parts by weight of the component (A) and the component (B) according to claim 1 and 0.5 to 3 parts by weight of an organic peroxide are kneaded at 120 to 190 ° C. A partially vulcanized rubber composition obtained by
Partially vulcanized rubber composition in which the weight ratio of component (B) is 5/95 to 40/60 3. A vulcanized rubber composition obtained by vulcanizing the rubber composition according to claim 1.