Claims
- 1. A resin composition for an automobile bumper comprising components (A), (B) and (C) described below:
- (A) 45 to 74% by weight of a crystalline ethylene-propylene block copolymer having
- (a) a flexural modulus of 15,000 kg/cm.sup.2 or more,
- (b) an ethylene content of 5 to 20% by weight,
- (c) an intrinsic viscosity (decalin, 135.degree. C.) of a portion soluble in p-xylene at room temperature of 3 or more,
- (d) a melt flow index (MI) of 21 to 70 g/10 min., and
- (e) a content of a portion insoluble in boiling n-heptane of 97% by weight or more;
- (B) 21 to 35% by weight of elastomer consisting essentially of:
- (i) component (I);
- (ii) components (I) and (II), having a weight ratio of (I) to {(I)+(II)} of from 0.5 to 1.0;
- (iii) components (I) and (III), having a weight ratio of (I) to {(I)+(III)} of from 0.5 to 1.0; or
- (iv) components (I), (II) and (III), having a weight ratio of (I) to {(I)+(II)+(III)} of from 0.5 to 1.0,
- (a) said component (I) being an amorphous ethylene-butene copolymer having a butene content of 10 to 25% by weight and a Mooney viscosity value (ML.sub.1+ 4, 100.degree. C.) of 5 to 20,
- (b) said component (II) being an amorphous ethylene-propylene copolymer having an ethylene content of 70 to 90% by weight and a Mooney viscosity value (ML.sub.1+4, 100.degree. C.) of 5 to 40, and
- (c) said component (III) being a hydrogenated block copolymer consisting of 10 to 40% by weight of an aromatic vinyl polymer block X and 60 to 90% by weight of a conjugate diene polymer block Y, having a structure of said block components being X-Y or X-(X-Y).sub.n, wherein n is 1 or 2, 90 mol% or more of said block Y being hydrogenated and the melt flow index (MI) of the hydrogenated block copolymer being 5 g/10 min. (230.degree. C., 2.16 kg) or more, and;
- (C) 5 to 20% by weight of talc having a combustion loss of 7% by weight or less, containing no particles having a diameter of 20 .mu.m or more and having an average particle diameter D.sub.50 of 1.0 to 3.0 .mu.m; wherein said resin composition has a melt flow index (MI) of 15 g/10 min. (230.degree. C.; 2.16 kg) or more and a surface hardness of 55 (Rockwell, R scale) or more.
- 2. A resin composition as claimed in claim 1, wherein the component (A) is composed of a crystalline ethylene-propylene block copolymer having (a) an ethylene content of 6 to 15% by weight, (b) a flexural modulus of 17,000 kg/cm.sup.2 or more, (c) an intrinsic viscosity (decalin, 135.degree. C.) of a portion soluble in p-xylene at room temperature of 4 or more, (d) a melt flow index of 25 to 50 and (e) a content of a portion insoluble in boiling n-heptane of 97.5% by weight or more.
- 3. A resin composition as claimed in claim 1, wherein the component (B) (I) is composed of an amorphous ethylene-butene copolymer having a butene content of 12 to 22% by weight and a Mooney viscosity ML.sub.1+4 (100.degree. C.) of 10 to 15.
- 4. A resin composition as claimed in claim 1, wherein the component (B) (II) is composed of an amorphous ethylene-propylene copolymer having an ethylene content of 75 to 85% by weight and a Mooney viscosity ML.sub.1+4 (100.degree. C.) of 10 to 30.
- 5. A resin composition as claimed in claim 1, wherein the component (B) (III) is composed of a hydrogenated rubber derived from the hydrogenation of the block polymer composed of 10 to 30% by weight of the aromatic vinyl compound polymer block component X and 90 to 70% by weight of the conjugated diene polymer block component Y.
- 6. A resin composition as claimed in claim 1, wherein the component (C) is composed of talc having a combustion loss of 5.5% by weight or less and a particle diameter of 1.0 to 2.5 .mu.m.
- 7. An automobile bumper obtained from a resin composition according to claim 1.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3-089854 |
Mar 1991 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/858,139 filed Mar. 27, 1992, now abandoned.
US Referenced Citations (6)
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Continuations (1)
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Number |
Date |
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Parent |
858139 |
Mar 1992 |
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