JP2003321564A - Foamable ept composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a foamable EPT (ethylene propylene terpolymer) composition for imparting an EPT foam by conventional foam molding keeping advantages of hydrosilicone crosslinked EPT. <P>SOLUTION: The EPT composition is constituted by blending (B) a hydrosilicone compound as a cross-linking agent, (C) a platinum-based catalyst, (D) 1,1'-azobis(cyclohexane-1-methylcarboxylate) as a foaming agent or (E) 1,1'-azobis(1-acetoxy-phenylethane) as a foaming agent to (A) an EPT containing vinyl norbornene as a diene monomer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ethylene / propylene / diene rubber (EP) which is hydrosilylated and crosslinked.
T) of the foamable composition.

[0002]

2. Description of the Related Art EPT products require a cross-linking (vulcanization) step in order to enhance the strength of the product. Currently, EPT is cross-linked by using sulfur or peroxide as a cross-linking agent. . However, crosslinking with sulfur requires a vulcanization accelerator, which has poor permanent compression strain and insufficient heat resistance, which may cause hygiene problems. Further, the crosslinking by peroxide is deteriorated when the crosslinking is carried out in contact with oxygen, has a strong odor and is not preferable in the working environment, and air vulcanization (HAV) cannot be practically performed.

Therefore, in recent years, it has been studied to apply a crosslinking system using a platinum catalyst used in silicone rubber to EPT, and EPT containing vinylnorbornene as a diene monomer is used as a raw material rubber and a hydrosilicone compound is used as a crosslinking agent. As a result, cross-linking by a hydrosilylation reaction has been put to practical use. Further, this crosslinking system has advantages such as excellent permanent compression strain, improvement of heat-resistant life, shortening of molding cycle by high-speed crosslinking, odorless hygiene requiring no vulcanization aid, and HAV capability.

[0004]

However, in such a hydrosilicone-crosslinked EPT, there is a possibility that the compounded substance may be poisoned due to the platinum catalytic reaction and the crosslinking may be inhibited. Commonly poisoned substances include sulfur, nitrogen, phosphorus, tin compounds, etc. When a foaming agent is used as a compounding substance, apart from the inorganic foaming agent, a commonly used organic foaming agent is used. For example, azobisisobutyronitrile (A
IBN), azodicarbonamide (ADCA), oxybis (benzenesulfonylhydrazide) (OBSH), etc. are poisoned and these foaming agents cannot be used. As a result, there is a problem that it is not possible to obtain a foamable hydrosilicone crosslinked EPT having excellent foamability, a fine cell structure, and excellent surface smoothness of the skin layer.

In view of the above problems, the present invention maintains the advantages of the hydrosilicone-crosslinked EPT and can obtain an EPT foam by ordinary foam molding.
It is an object to provide a PT composition.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a specific foaming agent does not cause poisoning of a platinum catalyst, and has completed the present invention. I arrived. 1. The present invention relates to (A) an EPT containing vinylnorbornene as a diene monomer, (B) a hydrosilicone compound as a crosslinking agent, (C) a platinum-based catalyst, and (D).
1,1'-azobis (cyclohexane-1 as a foaming agent
-Methyl carboxylate)
It is a T composition. 2. The present invention relates to (A) an EPT containing vinylnorbornene as a diene monomer, (B) a hydrosilicone compound as a crosslinking agent, (C) a platinum-based catalyst, and (E).
A foamable EPT composition containing 1,1′-azobis (1-acetoxy-phenylethane) as a foaming agent.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The foamable EPT composition of the present invention will be described below. In addition, hereinafter, simply referred to as “part” means “part by weight”.

In the present invention, as the raw material rubber (A), E containing vinyl norbornene as a diene component is used.
PT is used. The polymer is preferably about 4
Includes ethylene in the range of 0-85% by weight, about 0.25
Diene is contained in the range of up to 5% by weight.

As the hydrosilicone compound (B) as the crosslinking agent, an agent for crosslinking the rubber component by hydrosilylation can be used, and examples thereof include a multifunctional organosilicon compound. Preferably at least two in the molecule
Mention may be made of silicon hydride compounds in which silicon hydride having SiH groups reacts with EPT having vinyl groups.

As the platinum-based catalyst (C), a well-known hydrosilylation reaction catalyst that accelerates the addition reaction (hydrosilylation reaction) between the EPT having a vinyl group and the SiH group in the component (B) can be used. Examples thereof include chloroplatinic acid, platinum olefin complex, platinum vinyl siloxane complex, platinum black, platinum triphenylphosphine complex and the like.

(D) 1,1'-azobis (cyclohexane-1-methylcarboxylate), or (E)
1,1′-azobis (1-acetoxy-phenyl ethane) is a foaming agent to be blended in the foamable EPT composition of the present invention, and the blending amount thereof all contains vinyl norbornene as the (A) diene component. Usually about 0.01 to 50 parts, preferably 0.5 to 1 with respect to 100 parts of EPT.
It is recommended to set it to 0 copy. These foaming agents (D) and (E) are decomposed during heat-crosslinking and do not generate nitrogen, and are not affected by poisoning by the platinum-based catalyst, and there is no problem in crosslink foaming molding.

If necessary, the foamable EPT composition of the present invention may further contain additives. As additives, antioxidants, processing aids, reinforcing or non-reinforcing fillers, pigments, waxes, rubber process oils, extender oils, anti-sticking agents, antistatic agents, UV stabilizers, plasticizers
(Including esters), flame retardants, and other processing aids known in the rubber compounding art.

The expandable EPT composition of the present invention can be prepared by blending the respective components in any order and thoroughly mixing them. Mixing can be performed using a kneader, a twin roll, a twin-screw kneading extruder, and various mixers and other kneaders.

As a method for producing an EPT foam by foaming the expandable EPT composition of the present invention, conventionally known methods can be widely adopted. For example, the obtained expandable EPT composition can be crosslinked and expanded by heating to obtain an EPT foam. Foaming can be carried out in an arbitrary mold to obtain an EPT foam having a desired shape, and after the foamable EPT composition is extrusion-molded, it is continuously passed by passing through a heating tank as needed. It is also possible to obtain a strip-shaped EPT foam. The heating may be performed in two or more stages, and the heating method may be any method such as hot air heating or dielectric heating.

[0015]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Among the ingredients shown in Table 1, first, EPT, carbon black and a softening agent were kneaded by a 3L kneader, and then a hydrosilicone compound, a platinum catalyst, a retarder and a foaming agent were added to the kneaded material. The mixture was thoroughly kneaded with an 8-inch roll to prepare an unvulcanized EPT foam composition. Then this E
The PT foam composition was molded into a sheet having a size of 10 cm × 10 cm × 3 mm, and this was molded in a gear oven at 200 ° C. for 10 minutes.
Hot air vulcanization for 1 minute was performed. Then, secondary vulcanization was performed at 120 ° C. for 2 hours.

Example 2 and Comparative Examples 1 to 4 Example 1 except that the foaming agent shown in Table 1 was replaced.
A foamed sheet was molded in the same manner as in. Comparative Examples 1 to
The sample of 4 did not vulcanize and foam in the primary hot air vulcanization, so the secondary vulcanization was omitted.

[0018]

[Table 1]

(Note) (1) MPT made by Mitsui Chemicals, Inc. has a vinyl group EPT, PX-0
52 (V-2041) (2) Mitsubishi Chemical Co., Ltd. carbon black, # 3030B (3) Idemitsu Kosan Co., Ltd. softener (paraffin oil), P
W-380 (4) Shin-Etsu Chemical Hydrosilicone Compound, X-93
-1346 (5) Platinum catalyst manufactured by Shin-Etsu Chemical Co., Ltd., X-93-1410 (6) Delay agent manufactured by Shin-Etsu Chemical Co., Ltd., X-93-1122 (7) Foaming agent manufactured by GE Toshiba Silicone Co., Ltd. 1, 1'-
Azobis (1-acetoxy-phenyl ethane) (8) Shin-Etsu Chemical Co., Ltd. foaming agent, 1,1'-azobis (cyclohexane-1-methylcarboxylate) (9) Eiwa Chemical Co., Ltd. foaming agent, Vinylhole AC # LQ ( 10) Foaming agent manufactured by Eiwa Chemical Industry Co., Ltd., Cellular D (11) Foaming agent manufactured by Eiwa Chemical Industry Co., Ltd., Neocerbon N # 1
000S (12) Shin-Etsu Chemical Co., Ltd. foaming agent, KEP-13 (13) ◎ …… Good foaming, × …… No foaming

[0020]

The foam obtained from the expandable EPT composition of the present invention has a small compression set, has fine and uniform cells, and has weather strips, door packings for automobiles, or OA. It can be used as electronic parts such as rollers and parts for various industries.

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Claims (2)

[Claims] 1. An ethylene / propylene / diene rubber (EPT) containing vinyl norbornene as a diene monomer (A), a hydrosilicone compound as a cross-linking agent (B), a platinum-based catalyst (C) and a foaming agent (D). A foamable EPT composition containing 1,1′-azobis (cyclohexane-1-methylcarboxylate). 2. For (A) ethylene propylene diene rubber (EPT) containing vinyl norbornene as a diene monomer, (B) a hydrosilicone compound as a crosslinking agent, (C) a platinum catalyst and (E) a foaming agent. A foamable EPT composition containing 1,1′-azobis (1-acetoxy-phenylethane).