Patent US4164531A successfully refreshed from Google Patents.
US4164531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Injection molding of ultra high molecular weight polyethylene
Assignee: Mitsui Chemicals Inc
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Filing: 1977-12-08
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Granted: 1979-08-14
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Expires: 1997-12-08
Abstract
Abstract Process for injection molding ultra high molecular weight polyethylene by injecting the ultra high molecular weight polyethylene into a cavity having a volume 1.5-3.0 times that of the injected polyethylene at a shear rate of at least 50,000 sec.-1 measured at the gate of the injection nozzle and then compressing the cavity to a volume less than 1.5 times that of the injected polyethylene.
Inventors
- 👤 Takeshi Shiraki
- 👤 Shozo Hieda
- 👤 Tomokazu Ninomiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:44
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C45/56; B29C45/561; B29C43/00; B29C43/006; B29C45/0001; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/0658; B29K2023/0683; B29K2105/00; B29K2105/25; B29K2105/251
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
118 words
A process for injection molding of ultra high molecular weight polyethylene having an intrinsic viscosity of 10 to 30 when measured in decalin at 135° C. and a melt index of up to 0.01 which comprises injecting the polyethylene into a mold cavity having a volume of 1.7 to 2.5 times that of the injected polyethylene at a shear rate of from 200,000 to 500,000 sec -1 measured at the gate of the injection nozzle at a temperature of from 150° C. to 300° C. to form powder particles and reducing the mold cavity volume to less than 1.5 times that of the injected polyethylene to compress and unite the powder particles and form a coherent molded product.
Claim 2
Dependent Claim
118 words
A process for injection molding of ultra high molecular weight polyethylene having an intrinsic viscosity of 10 to 30 when measured in decalin at 135° C. and a melt index of up to 0.01 which comprises injecting the polyethylene into a mold cavity having a volume of 1.7 to 2.5 times that of the injected polyethylene at a shear rate of from 200,000 to 500,000 sec -1 measured at the gate of the injection nozzle at a temperature of from 150° C. to 300° C. to form powder particles and reducing the mold cavity volume to less than 1.5 times that of the injected polyethylene to compress and unite the powder particles and form a coherent molded product.
Claim 3
Dependent Claim
121 words
A process for injection molding of ultra high molecular weight polyethylene having an intrinsic viscosity of from 3 to 30 when measured in decalin at 135° C. and a melt index up to 0.01 which comprises injecting the polyethylene into a mold cavity having a volume of 1.5 to 3.0 times that of the injected polyethylene at a shear rate of from 50,000 sec. -1 to 1,000,000 sec. -1 measured at the gate of the injection nozzle at a temperature of from 140° C. to 300° C. to form powder particles, and then decreasing the mold cavity volume to less than 1.5 times that of the injected polyethylene to compress and unite the powder particles and form a coherent molded product.
Claim 4
Dependent Claim
121 words
A process for injection molding of ultra high molecular weight polyethylene having an intrinsic viscosity of from 3 to 30 when measured in decalin at 135° C. and a melt index up to 0.01 which comprises injecting the polyethylene into a mold cavity having a volume of 1.5 to 3.0 times that of the injected polyethylene at a shear rate of from 50,000 sec. -1 to 1,000,000 sec. -1 measured at the gate of the injection nozzle at a temperature of from 140° C. to 300° C. to form powder particles, and then decreasing the mold cavity volume to less than 1.5 times that of the injected polyethylene to compress and unite the powder particles and form a coherent molded product.
Claim 5
Dependent Claim
32 words
A process according to claim 2 in which the cavity volume is compressed to a volume of less than 1.5 times, but not less than 1.1 times that of the injected polyethylene.
Claim 6
Dependent Claim
19 words
A process according to claim 2 in which the shear rate is from 200,000 to 500,000 sec. -1 .
Claim 7
Dependent Claim
21 words
A process according to claim 2 in which the volume of the cavity is 1.7-2.5 times that of the injected polyethylene.
Claim 8
Dependent Claim
38 words
A process according to claim 2 in which the ultra high molecular weight polyethylene has an intrinsic viscosity η measured at 135° C. in decalin of 10-30 and a melt Index (MI 20 ) of up to 0.01.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-13 | 1983-02-12 | 1983-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-13 | 1987-02-12 | 1987-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-13 | 1991-02-12 | 1991-08-14 | $7700.00 | Window Closed / Lapsed |