US4504534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Core material for automobile bumpers
Assignee: JSP Corp
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Filing: 1984-06-13
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Granted: 1985-03-12
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Expires: 2004-06-13
Abstract
Abstract A core material for automobile bumpers which is composed of a molded article of foamed particles of a polypropylene-type resin. The molded article has a density of 0.015 to 0.045 g/cm3 and a compression stress at 50% compression of at least 1 kg/cm2. The core material simultaneously has excellent energy absorbing property and dimensional recovery and a low density.
Inventors
- 👤 Akira Adachi
- 👤 Takashi Kubota
- 👤 Yukio Okada
- 👤 Kenichi Miyazaki
- 👤 Taro Hagiwara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:26
CPC Classifications
B; B60; B60R; B60R19/00; B60R19/02; B60R19/18; B60R19/22; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/15; Y10S264/16; Y10S264/18; Y10T; Y10T428/00; Y10T428/23; Y10T428/233; Y10T428/239
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
91 words
In an automobile bumper which is composed of a core material and a surface covering material, the improvement wherein said core material is composed of a molded article of foamed particles of a homopolymer of propylene or a copolymer of propylene with 1 to 30% by weight of an ethylenically unsaturated monomer copolymerizable with it, said molded article having a density of 0.015 to 0.045 g/cm 3 and a compression stress at 50% compression of at least 1 kg/cm 2 , and the said surface covering material is a synthetic resin.
Claim 2
Dependent Claim
91 words
In an automobile bumper which is composed of a core material and a surface covering material, the improvement wherein said core material is composed of a molded article of foamed particles of a homopolymer of propylene or a copolymer of propylene with 1 to 30% by weight of an ethylenically unsaturated monomer copolymerizable with it, said molded article having a density of 0.015 to 0.045 g/cm 3 and a compression stress at 50% compression of at least 1 kg/cm 2 , and the said surface covering material is a synthetic resin.
Claim 3
Dependent Claim
28 words
An automobile bumper of claim 1 wherein the copolymer is a random copolymer of ethylene and propylene with an ethylene unit content of 1 to 30% by weight.
Claim 4
Dependent Claim
53 words
An automobile bumper of claim 1 wherein the core material of claim 1 which has an energy absorption efficiency of at least 70% and a dimensional recovery of at least 90%, and when heated at a temperature of 100° C. for a period of 22 hours, a volume shrinkage of less than 20%.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-11 | 1988-09-10 | 1989-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-11 | 1992-09-10 | 1993-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-11 | 1996-09-10 | 1997-03-12 | $7700.00 | Window Closed / Lapsed |