Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-03-27
2003-09-09
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S306000
Reexamination Certificate
active
06617383
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermoplastic elastomer composition. More specifically, it relates to a thermoplastic elastomer composition superior in processability and dynamic fatigue resistance even under a low temperature such as −20° C. and also to a tire, particularly a tire suitable for use in a cold area, using the same as a tire member.
2. Description of the Related Art
To improve the dynamic fatigue resistance, while maintaining a balance between the flexibility and the gas permeation resistance, it is known from Japanese Unexamined Patent Publication (Kokai) No. 8-259741 that a nylon resin and a rubber component are formed into a thermoplastic elastomer composition by dynamic vulcanization, which is then used for an air permeation preventive layer (e.g., inner liner). However, there was the problem that the thermoplastic elastomer composition was not sufficient in dynamic fatigue resistance at a low temperature such as −20° C. and, therefore, was not necessarily suitable for use, as a tire, in a cold area.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a thermoplastic elastomer composition superior in dynamic fatigue resistance even under a low temperature such as −20° C. and a cold region tire using this composition as a tire member.
Other objects and advantages of the present invention will be apparent from the following description.
In accordance with the present invention, there is provided a thermoplastic elastomer composition comprising a thermoplastic resin (A) and a rubber composition (B) dispersed in the thermoplastic resin (A), wherein a stress at the time of 2.5% elongation in a stress-strain curve of the thermoplastic elastomer composition is 0.1 to 50 MPa and a ratio of the stress (M
200
) at −20° C. and 200% elongation and the stress (M
100
) at −20° C. and 100% elongation is 1.0<M
200
/M
100
<2.0.
In accordance with the present invention, there is also provided the above thermoplastic elastomer composition, wherein the value of the first order differential of the stress-strain curve of the thermoplastic elastomer composition monotonously decreases in a 2 to 20% strain region.
In accordance with the present invention, there is further provided the above thermoplastic elastomer composition, wherein an air permeation coefficient at 30° C. of the thermoplastic elastomer composition is more than 25×10
−12
cc cm/cm
2
·sec·cmHg and not more than 100×10
−12
cc·cm/cm
2
·sec·cmHg and a Young's modulus at −20° C. is not more than 250 MPa.
In accordance with the present invention, there is still further provided the above thermoplastic elastomer composition, wherein the thermoplastic resin (A) is a polyamide resin having the rubber component (B) dispersed therein, at least one member selected from the group consisting of polyamide plasticizer (C1) and thermoplastic elastomers (C2) is contained in the composition and a ratio of the components, where the total is made 100% by weight, is as follows:
(A) polyamide resin: 15 to 59% by weight,
(B) rubber composition: 40 to 70% by weight, and
(C) polyamide thermoplastizer+thermoplastic elastomer (C1+C2): 1 to 30% by weight.
In accordance with the present invention, there is still further provided the above thermoplastic elastomer composition, wherein the elongation at break at −20° C. is not less than 300%, the Young's modulus at −20° C. is in a range not more than 250 MPa, and the product of the elongation at break and the Young's modulus is 10,000 to 100,000 (%·MPa).
In accordance with the present invention, there is still further provided the above thermoplastic elastomer composition, wherein the ratio, by weight, of composition of the components satisfies the following relation:
1.0≦(
B+C
2)/(
A+C
1)≦2.5
In accordance with the present invention, there is still further provided a tire using the thermoplastic elastomer composition.
REFERENCES:
patent: 4130534 (1978-12-01), Coran et al.
patent: 4197379 (1980-04-01), Coran et al.
patent: 5910544 (1999-06-01), Ozawa et al.
patent: 0 633 152 (1995-01-01), None
patent: 0 722 850 (1996-07-01), None
patent: 0 969 039 (2000-01-01), None
Database WPI; Section Ch., Week 200010, Derwent Publication Ltd., London, GB; AN 2000-111747, XP002172817 & JP 11 349734 A (Yokohama Rubber Co., Ltd.), Dec. 21, 1999, Abstract.
Database WPI; Section Ch., Week 200016, Derwent Publications Ltd., London, GB; AN 2000-177135, XP002172818 & JP 2000 026720 A (Yokohama Rubber Co., Ltd.), Jan. 25, 2000, Abstract.
Hara Yuichi
Ikawa Masahiro
Kanenari Daisuke
Soeda Yoshihiro
Tanaka Katsuhiro
Arent Fox Kintner & Plotkin & Kahn, PLLC
Cain Edward J.
The Yokohama Rubber Co. Ltd.
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