US4247650A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Expanded particulate material of polyolefin resin
Assignee: Asahi Kasei Corp
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Filing: 1980-03-05
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Granted: 1981-01-27
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Expires: 2000-03-05
Abstract
Abstract Expanded particles of a crosslinked polyolefin resin, each particle with uniformly spherical shape, having an average diameter of 1.4 to 5.5 mm, an average expansion ratio of 18 to 37 and specific compression coefficient of 1.6×10 -3 to 4.0×10 -3 , are found to be produced by two-step foaming operations. They are useful for various purposes such as filtrating material, fillers in stuffed specimens and, especially for preparation of molded articles having constricted portions, giving excellent moldings having smooth surface without failure at corner or edge portions.
Inventors
- 👤 Hiroshi Shimizu
- 👤 Hiroshi Sato
- 👤 Nobuo Miura
- 👤 Shuzo Inada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:24
CPC Classifications
B; B29; B29C; B29C67/00; B29C67/20; C; C08; C08J; C08J9/00; C08J9/22; C08J9/228; C08J9/232; C08J2323/00; C08J2323/02; C08J2323/04; Y; Y10; Y10S; Y10S264/00; Y10S264/09; Y10S264/18
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
115 words
A particulate resin material comprising expanded crosslinked polyolefin resin particles which are substantially spherical, resilient, free-flowing, uniform in particle size and moldable in a cavity, each particle having a structure substantially constituted of closed cells without void, and which have an average particle size ranging from 1.4 to 5.5 millimeters, an average expansion ratio ranging from 18 to 37 based on the original volume of unexpanded resin particles and a compression coefficient ranging from 1.6×10 -3 to 4.0×10 -3 as determined from the following formula: S/(R×F) wherein S represents total energy for compression under pressure of 1 kg/cm 2 , R average expansion ratio and F flowability, respectively, of the expanded crosslinked polyolefin resin particles.
Claim 2
Dependent Claim
115 words
A particulate resin material comprising expanded crosslinked polyolefin resin particles which are substantially spherical, resilient, free-flowing, uniform in particle size and moldable in a cavity, each particle having a structure substantially constituted of closed cells without void, and which have an average particle size ranging from 1.4 to 5.5 millimeters, an average expansion ratio ranging from 18 to 37 based on the original volume of unexpanded resin particles and a compression coefficient ranging from 1.6×10 -3 to 4.0×10 -3 as determined from the following formula: S/(R×F) wherein S represents total energy for compression under pressure of 1 kg/cm 2 , R average expansion ratio and F flowability, respectively, of the expanded crosslinked polyolefin resin particles.
Claim 3
Dependent Claim
14 words
A particulate resin material as in claim 1, wherein the polyolefin resin is polyethylene.
Claim 4
Dependent Claim
24 words
A particulate resin material as in claim 2, wherein the polyethylene is a low density polyethylene having a density of from 0.910 to 0.930.
Claim 5
Dependent Claim
51 words
A particulate resin material as in any of claims 1 to 3, wherein the average particle size is in the range from 2.0 to 4.5 mm, the average expansion ratio in the range from 23 to 32 and the compression coefficient in the range from 2.2×10 -3 to 3.6×10 -3 .
Claim 6
Dependent Claim
64 words
A molded article comprising expanded cross-linked polyolefin resin particles integrally closely bonded between the expanded particles, having an average density of 0.12 to 0.028 g/cm 3 and a compression strength (kg/cm 2 at 25% compression) per its density (g/cm 3 ) of 14 to 18, and being substantially smooth on its surface with substantially no failure at corners or edges even at constricted portions.
Claim 7
Dependent Claim
64 words
A molded article comprising expanded cross-linked polyolefin resin particles integrally closely bonded between the expanded particles, having an average density of 0.12 to 0.028 g/cm 3 and a compression strength (kg/cm 2 at 25% compression) per its density (g/cm 3 ) of 14 to 18, and being substantially smooth on its surface with substantially no failure at corners or edges even at constricted portions.
References Cited (Backward Citations)
US2948664A
Cited
US3823213A
Cited
US3616365A
Cited
US3743611A
Cited
US3709806A
Cited
US3886100A
Cited
US3953558A
Cited
US3959189A
Cited
US4108934A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |