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US4366263A
Expired / Lapsed
US
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Expanded cross-linked polyethylene particle, a molded product thereof and the methods thereof
Assignee: Asahi Kasei Corp
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Filing: 1980-12-05
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Granted: 1982-12-28
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Expires: 2000-12-05
Abstract
Abstract An expansion-molded product made from expanded cross-linked polyethylene particles each of which has an outer skin and inner cellular core, said outer skin each being fused and welded together to form an interfacial membrane whose average thickness is as thick as at least three times that of a cell membrane of the inner cellular core, is prepared by charging a lot of the particles into a mold, heating the particles therein to such an extent that the space among the particles is filled and then aging thus obtained molded product. The expanded particle each has a structure having an outer skin on an inner cellular core, the outer skin being as thick as at least three times cell membrane of the inner cellular core. The expandable particles are prepared by impregnating a foaming agent into the cross-linked polyethylene particles and heating so that the expandable particles are subjected to a step in which the foaming agent existing in the surface thereof is preferentially forced to evaporate.
Inventors
- 👤 Eiya Sato
- 👤 Tsukasa Yamagishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:36
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/22; C08J9/228; B; B29; B29C; B29C67/00; B29C67/20; B29C67/205; C08J9/16; C08J9/18; B29C44/00; B29C44/34; B29C44/3415; B29C44/3426; B29K; B29K2025/00; C08J2203/00; C08J2203/14; C08J2203/142; C08J2323/00; C08J2323/02; C08J2323/04; Y; Y10; Y10S; Y10S264/00; Y10S264/09; Y10S264/15; Y10S264/18
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
205 words
An expansion-molded product of cross-linked polyethylene, said expansion-molded product: (1) being a number of expanded cross-linked polyethylene particles having a thick skin layer, which particles are closely contacted and adhered to each other at the skin layers of adjacent particles to form a foam having a density of 0.025 to 0.05 g/cm 3 , (2) having a substantial average thickness of the interfacial membranes, which are formed by thermally fusing and welding the particle surfaces together, being approximately not lower than 3 times the thickness, as compared with the substantial average thickness of cell membranes in each particle, (3) having a melting point of 107° to 124° C., (4) having a compressure stress (R) kg/cm 2 required for 25% compression which satisfies the equation: 1/140 (270-6/D)≦R≦1/140 (315-6/D) wherein D means density g/cm 3 , (5) having a cavity coefficient, which represents smoothness of the surface of the product, if not higher than 10, (6) having a water absorption ratio of not higher than 0.3% by volume, (7) having a head resistant compressive creep at 80° C. of not higher than 35% by thickness, and (8) having a dimensional change ratio after standing at 90° C. for 96 hours of not higher than 2% by length.
Claim 2
Dependent Claim
205 words
An expansion-molded product of cross-linked polyethylene, said expansion-molded product: (1) being a number of expanded cross-linked polyethylene particles having a thick skin layer, which particles are closely contacted and adhered to each other at the skin layers of adjacent particles to form a foam having a density of 0.025 to 0.05 g/cm 3 , (2) having a substantial average thickness of the interfacial membranes, which are formed by thermally fusing and welding the particle surfaces together, being approximately not lower than 3 times the thickness, as compared with the substantial average thickness of cell membranes in each particle, (3) having a melting point of 107° to 124° C., (4) having a compressure stress (R) kg/cm 2 required for 25% compression which satisfies the equation: 1/140 (270-6/D)≦R≦1/140 (315-6/D) wherein D means density g/cm 3 , (5) having a cavity coefficient, which represents smoothness of the surface of the product, if not higher than 10, (6) having a water absorption ratio of not higher than 0.3% by volume, (7) having a head resistant compressive creep at 80° C. of not higher than 35% by thickness, and (8) having a dimensional change ratio after standing at 90° C. for 96 hours of not higher than 2% by length.
Claim 3
Dependent Claim
21 words
The expansion-molded product as defined in claim 1, wherein the melting point of the product is approximately 110° to 120° C.
Claim 4
Dependent Claim
186 words
An exapansion-molded product of cross-linked polyethylene, said expansion-molded product: (1) being a number of expanded cross-linked polyethylene particles having a thick skin layer, which particles are closely contacted and adhered to each other at the skin layers of adjacent particles to form a foam having a density of 0.025 to 0.05 g/cm 3 , (2) having a substantial average thickness of the interfacial membranes, which are formed by thermally fusing and welding the particle surfaces together, being approximately not lower than 3 times the thickness, as compared with the subsantial average thickness of cell membranes in each particle, (3) having a melting point of 107° to 124° C., (4) having a compressure stress (R) kg/cm 2 required for 25% compression which satisfies the equation: 1/140 (270-6/D)≦R≦1/140 (315-6/D) wherein D means density g/cm 3 , (5) having a water absorption ratio of not higher than 0.3% by volume, (6) having a head resistant compressive creep at 80° C. of not higher than 35% by thickness, and (7) having a dimensional change ratio after standing at 90° C. for 96 hours of not higher than 2% by length.
Claim 5
Dependent Claim
186 words
An exapansion-molded product of cross-linked polyethylene, said expansion-molded product: (1) being a number of expanded cross-linked polyethylene particles having a thick skin layer, which particles are closely contacted and adhered to each other at the skin layers of adjacent particles to form a foam having a density of 0.025 to 0.05 g/cm 3 , (2) having a substantial average thickness of the interfacial membranes, which are formed by thermally fusing and welding the particle surfaces together, being approximately not lower than 3 times the thickness, as compared with the subsantial average thickness of cell membranes in each particle, (3) having a melting point of 107° to 124° C., (4) having a compressure stress (R) kg/cm 2 required for 25% compression which satisfies the equation: 1/140 (270-6/D)≦R≦1/140 (315-6/D) wherein D means density g/cm 3 , (5) having a water absorption ratio of not higher than 0.3% by volume, (6) having a head resistant compressive creep at 80° C. of not higher than 35% by thickness, and (7) having a dimensional change ratio after standing at 90° C. for 96 hours of not higher than 2% by length.
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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) | 1985-12-27 | 1986-06-28 | 1986-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-27 | 1990-06-28 | 1990-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-27 | 1994-06-28 | 1994-12-28 | $7700.00 | Window Closed / Lapsed |