JP2000344996A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject rubber composition that maintains its vulcanization rate at such a sufficiently satisfactory level by using an ethylene-α-olefin- non-conjugated diene copolymer rubber modified by a vinyl aromatic compound as well as a primary amine. SOLUTION: This rubber composition comprises (A) an ethylene-α-olefin-non- conjugated diene copolymer rubber modified by an aromatic vinyl compound or by the aromatic vinyl compound, an α,β-unsaturated carboxylic ester, acrylonitrile or methacrylonitrile and (B) a primary amine. The content of the component B is preferably 1-20 mmol per 100 g of the component A. The content of aromatic vinyl compound in the component A is preferably 5-100 g per 100 g of the rubber. The α-olefin in the component A is preferably propylene, while the non-conjugated diene is preferably 5-ethylidene-2-norbornene and/or dicyclopentadiene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rubber composition. More specifically, the present invention relates to an ethylene-α-olefin-non-conjugated diene copolymer modified with a vinyl aromatic compound or a vinyl aromatic compound and an α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile The present invention relates to a rubber composition containing rubber and maintaining a vulcanization rate at a sufficiently satisfactory level.

[0002]

2. Description of the Related Art A vinyl aromatic compound represented by styrene or an ethylene-α-olefin-non-conjugated diene copolymer modified with an α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile is used. The polymer rubber is unmodified ethylene-α
-Compared to olefin-non-conjugated diene-based copolymer rubber, even if the unvulcanized compound viscosity is low, it becomes high in hardness when vulcanized, and is excellent in abrasion resistance and cold resistance, but has a low vulcanization rate There is a problem that. A low vulcanization rate reduces productivity and is a major problem, particularly from a practical point of view.

[0003]

Under such circumstances, the problem to be solved by the present invention is to provide a vinyl aromatic compound or a vinyl aromatic compound and an α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile. An object of the present invention is to provide a rubber composition containing a modified ethylene-α-olefin-nonconjugated diene copolymer rubber and maintaining a vulcanization rate at a sufficiently satisfactory level.

[0004]

That is, the present invention relates to a rubber composition containing the following components (A) and (B). (A): vinyl aromatic compound or vinyl aromatic compound and ethylene modified with α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile
α-olefin-non-conjugated diene copolymer rubber (B): primary amine

[0005]

DETAILED DESCRIPTION OF THE INVENTION The component (A) of the present invention is a vinyl aromatic compound or an ethylene-α-olefin modified with a vinyl aromatic compound and an α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile. −
It is a non-conjugated diene copolymer rubber.

Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene,
-Methyl-1-pentene, 1-octene, 1-decene and the like, and propylene and 1-butene are usually used.

As non-conjugated dienes, for example, 1,4
-Hexadiene, 1,6-octadiene, 2-methyl-
Linear non-conjugated dienes such as 1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene; cyclohexadiene, dicyclopentadiene, methyltetraindene, 5-vinylnorbornene 2,3-diisopropylidene-5-cyclic non-conjugated dienes such as, 5-ethylidene-2-norbornene and 6-chloromethyl-5-isopropylenyl-2-norbornene
Norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 1,3,7-octatriene, 1,4,9
A triene such as decatriene, one of which may be used alone, or two or more of which may be used in combination; In addition, from the viewpoint of copolymerization reactivity and crosslinking reaction rate, 5
-Ethylidene-2-norbornene and / or 5-ethylidene-2-norbornene and dicyclopentadiene are preferred.

The ratio (molar ratio) of ethylene / α-olefin in the ethylene-α-olefin-non-conjugated diene copolymer rubber is usually 1 / (0.1 to 1). Also,
As for the non-conjugated diene, the ratio (molar ratio) of ethylene / non-conjugated diene is usually set to 1 / (0.005 to 0.2).

As the vinyl aromatic compound, styrene,
Examples thereof include o-methylstyrene, p-methylstyrene, m-methylstyrene, and α-methylstyrene, with styrene being preferred. The content of the vinyl aromatic compound in (A) is usually 5 to 100 g of the ethylene-α-olefin-nonconjugated diene copolymer rubber.
100 g. Ethylene-α-olefin-non-conjugated diene copolymer rubber is modified with an aromatic compound, whereby high hardness can be obtained even in a low-viscosity composition,
Moreover, it becomes excellent in wear resistance and cold resistance.

Examples of the α, β-unsaturated carboxylic acid ester include acrylic acid ester, methacrylic acid ester and glycidyl methacrylate. (A)
The content of the α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile in the above-mentioned is based on the ethylene-α-olefin-non-conjugated diene copolymer rubber 100
g is usually 20 g or less, preferably 1 to 15 g.
g. Ethylene-α-olefin-non-conjugated diene copolymer rubber is modified with α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile in addition to the aromatic compound, so that it can be used in combination with a resin. , Cohesion or compatibility are improved.

[0011] (A) is obtained by a suspension method using an autoclave or a bulk method using an extruder.
The olefin-non-conjugated diene copolymer rubber may be modified with an aromatic compound or a vinyl aromatic compound and an α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile. For details, see JP-B-57-40
166, JP-B-58-53643, JP-B-62-10565, JP-B-63-64446, JP-B-57-13567, and JP-A-4-320.
411 and the like.

Component (B) of the present invention is a primary amine. Among the primary amines, primary alkylamines having an alkyl group having 6 to 18 carbon atoms are preferred from the viewpoint of mixing into rubber using a processing machine, and n-alkylamines are particularly preferred. Is n-octadecylamine, n-hexadecylamine, n-dodecylamine,
and n-octylamine.

The content of (B) in the rubber composition of the present invention is preferably from 1 to 20 mmol, more preferably from 2 to 18 mmol, per 100 g of (A). If the content of (B) is too small, a sufficient vulcanization rate cannot be obtained, while if the content of (B) is too large, bloom or bleeding occurs and the surface state deteriorates.

The method for obtaining the rubber composition of the present invention includes:
For example, the following method can be used. That is,
(A) and if necessary, a reinforcing agent such as carbon black, a softening agent such as process oil, an activator such as polyethylene glycol or stearic acid, a processing aid such as a fatty acid metal salt, and a vulcanization accelerator such as zinc oxide. And a white filler such as calcium carbonate (a bulking agent) are kneaded using a Banbury or a kneader to form a compound. Next, (B), sulfur as a vulcanizing agent, and, if necessary, a vulcanization accelerator for thiazoles, dithioates and thiurams commonly used in rubbers are added to the compound with an open roll, a kneader, or the like. The rubber composition of the present invention can be obtained by kneading using the above method.
(B) may be previously mixed with (A).

For vulcanizing the rubber composition of the present invention, for example, a hot pressing method, a hot air heating method, a high frequency heating method, a molten salt heating method, or the like can be used. The vulcanization conditions include, for example, a temperature of 130 to 200 ° C. and a time of 1 to 60 minutes.

The vulcanized rubber obtained by vulcanizing the rubber composition of the present invention can be particularly suitably used in the fields of sealing rubber for automobiles and buildings, belts, rolls and the like.

[0017]

Next, the present invention will be described by way of examples. Examples 1 to 3, Comparative Examples 1 and 2, and Reference Example 1 (A) in Table 1 or EPDM (EPD manufactured by Sumitomo Chemical Co., Ltd.)
M, ethylene content 58% by weight, diene (5-ethylidene-2-norbornene) content 4.5% by weight, Mooney viscosity ML _{1 + 4} 150 ° C 74, carbon black (“Asahi 60G” manufactured by Asahi Carbon Co., Ltd.), process A compound was obtained by kneading oil ("Sunthene 4240" manufactured by Nippon Sun Oil Co., Ltd.), stearic acid and zinc oxide with a Banbury mixer. Next, the compound (B) and sulfur and a vulcanization accelerator ("Axel BZ", "Axel M", "Axel TRA",
"Accel TMT") using an open roll.
A rubber composition was obtained by kneading. Next, it was vulcanized using a hot press to obtain a vulcanized product. Vulcanization conditions are 160 ° C x
10 minutes to 25 minutes. Measure the items listed in Table 2
An evaluation was performed. The results are shown in Table 2.

[0018]

[Table 1]

[Description of Table 1] (A): A modified ethylene-propylene-non-conjugated diene copolymer rubber (composition: 70% by weight of EPDM, 30% by weight of styrene (43 g of styrene per 100 g of EPDM)) was prepared by a suspension method. Obtained. As a base EPDM, EPDM manufactured by Sumitomo Chemical Co., Ltd., ethylene content 56% by weight, diene (5-ethylidene-2-norbornene) content 4.0% by weight, and Mooney viscosity ML _{1 + 4} 125 ° C 62 were used. (B): Primary amine ("ARME" manufactured by Lion Akzo)
EN18D "n-octadecylamine). () In the table
(A) 100 g of “ARMEN18
D ”(mmol).

[0020]

[Table 2]

[Explanation of Table 2] In Examples 1 to 3 in which (B) was added to (A), the vulcanization rate (t'9 at 160 ° C. ODR)
0 or in the evaluation at 125 ° C. t5) is Comparative Example 1.
It can be seen that it is higher and the level of the reference example. In Comparative Example 2 to which a large amount of (B) was added, the sheet surface was deteriorated.

From the results, it can be seen that the uncured ML _{1 + 4} 100 ° C.
(Unvulcanized compound viscosity) and Hs (JIS)
-A) Evaluation of (hardness of vulcanized sheet) shows that modified EPDM (A) has a lower unvulcanized compound viscosity than unmodified EPDM, but a higher hardness is obtained by vulcanization. I understand.

[0023]

As described above, according to the present invention, a vinyl aromatic compound or a vinyl aromatic compound and α, β-
Provided is a rubber composition containing an ethylene-α-olefin-non-conjugated diene copolymer rubber modified with an unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile, and maintaining a vulcanization rate at a sufficiently satisfactory level. I was able to.

Claims (5)

[Claims] 1. A rubber composition containing the following components (A) and (B). (A): vinyl aromatic compound or vinyl aromatic compound and ethylene modified with α, β-unsaturated carboxylic acid ester, acrylonitrile or methacrylonitrile
α-olefin-non-conjugated diene copolymer rubber (B): primary amine 2. The rubber composition according to claim 1, wherein the vinyl aromatic compound (A) is styrene, and the α, β-unsaturated carboxylic acid ester is an acrylic acid ester, a methacrylic acid ester or glycidyl methacrylate. 3. The rubber composition according to claim 1, wherein the α-olefin of (A) is propylene and the non-conjugated diene is 5-ethylidene-2-norbornene and / or dicyclopentadiene. 4. The rubber composition according to claim 1, wherein (B) is an n-alkylamine having 6 or more carbon atoms. 5. The rubber composition according to claim 1, wherein the content of (B) is
(A) 1 to 20 mmol per 100 g.
The rubber composition as described in the above.