Patent US4657937A successfully refreshed from Google Patents.
US4657937A
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Energy absorber
Assignee: JAPAN STYRENE PAPER Corp A CORP OF JAPAN
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Filing: 1986-01-30
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Granted: 1987-04-14
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Expires: 2006-01-30
Abstract
Abstract An energy absorber suitable for use as a bumper core or the like is formed of an expansion-molded article of prefoamed particles. The prefoamed particles use, as the base resin thereof, a resin obtained by impregnating high-density polyethylene with an aromatic vinyl monomer and polymerizing the monomer. The absorber has a density ( rho ) of 0.015-0.15 g/cm3 and satisfies the following relation: E20/ rho >/=45 kgxcm/g wherein E20 (kgxcm/cm3) means the quantity of energy absorbed upon 70% compression at 20 DEG C. and rho has the same meaning as defined above.
Inventors
- 👤 Hideki Kuwabara
- 👤 Masato Naito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:52
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/22; C08J9/228; C08J9/232; B; B60; B60R; B60R19/00; B60R19/02; B60R19/18; B60R19/22; C08J9/16; C08J9/18; C08J2351/00; C08J2351/06; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
78 words
An energy absorber comprising an expansion-molded article of prefoamed particles which use, as the base resin thereof, a resin obtained by impregnating high-density polyethylene with an aromatic vinyl monomer and polymerizing the monomer, said absorber having a density (ρ) of 0.015-0.15 g/cm 3 and satisfying the following relation: E.sub.20 /ρ≧45 kg·cm/g wherein E 20 (kg·cm/cm 3 ) means the quantity of energy absorbed upon 70% compression at 20° C. and ρ has the same meaning as defined above.
Claim 2
Dependent Claim
78 words
An energy absorber comprising an expansion-molded article of prefoamed particles which use, as the base resin thereof, a resin obtained by impregnating high-density polyethylene with an aromatic vinyl monomer and polymerizing the monomer, said absorber having a density (ρ) of 0.015-0.15 g/cm 3 and satisfying the following relation: E.sub.20 /ρ≧45 kg·cm/g wherein E 20 (kg·cm/cm 3 ) means the quantity of energy absorbed upon 70% compression at 20° C. and ρ has the same meaning as defined above.
Claim 3
Dependent Claim
25 words
An energy absorber according to claim 1, wherein the content of the aromatic vinyl monomer amounts to 10-60 wt. % of the whole expansion-molded article.
Claim 4
Dependent Claim
20 words
An energy absorber according to claim 1 wherein the high-density polyethylene has a density of from 0.94-0.97 g/gm 3 .
Claim 5
Dependent Claim
19 words
An energy absorber according to claim 1 wherein the high-density polyethylene has a density of 0.955-0.97 g/cm 3 .
Claim 6
Dependent Claim
19 words
An energy absorber according to claim 1 wherein said absorber has a density (ρ) of 0.02-0.1 g/cm 3 .
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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) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |