US4792588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyethylene composition
Assignee: Mitsui Chemicals Inc
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Filing: 1986-06-26
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Granted: 1988-12-20
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Expires: 2006-06-26
Abstract
Abstract A polyethylene composition having excellent melt moldability which substantially comprises an ultrahigh-molecular-weight polyethylene having a molecular weight of, for example, at least about 1,650,000 and a low-molecular-weight to high-molecular-weight polyethylene having a molecular weight of, for example, about 1500 to about 360,000. The composition is produced by a multi-stage polymerization process involving a step of producing the ultrahigh-molecular-weight polyethylene and a step of producing the low-molecular-weight to high-molecular-weight polyethylene.
Inventors
- 👤 Michiharu Suga
- 👤 Hideo Ishikawa
- 👤 Yoshinori Akana
- 👤 Junichi Yoshitake
- 👤 Masayuki Kondoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:10
CPC Classifications
C; C08; C08F; C08F10/00; C08F10/02; C08F110/00; C08F110/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
222 words
A polyethylene composition characterized in that: (1) said composition is produced by a multistage polymerization process in which in the presence of a Ziegler-type catalyst formed from (A) a highly active titanium catalyst component comprising magnesium, titanium and halogen as essential components and (B) an organoaluminum compound catalyst component, ethylene or ethylene and a small amount of an alpha-olefin are polymerized in at least one polymerization step to form ultrahigh-molecular-weight polyethylene having an intrinsic viscosity of at least 12 dl/g, and ethylene or ethylene and a small amount of an alpha-olefin are polymerized in the presence of hydrogen in another.polymerization step to form low-molecular-weight to high-molecular-weight polyethylene having an intrinsic viscosity of 0.1 to 5 dl/g, (2) said ultrahigh-molecular-weight polyethylene has an intrinsic viscosity, measured in decalin at 135° C., of at least 12 dl/g, and said low-molecular-weight to high-molecular-weight polyethylene has an intrinsic viscosity, measured in decalin at 135° C., of 0.1 to 5 dl/g, (3) the proportion of said ultrahigh-molecular-weight polyethylene is in the range of 20 to 95% by weight based on the total weight of said ultrahigh-molecular-weight polyethylene and said low-molecular-weight to high-molecular-weight polyethylene, and (4) said polyethylene composition consists substantially of said ultrahigh-molecular-weight polyethylene and said low-molecular-weight to high-molecular-weight polyethylene and has an intrinsic viscosity [η]c, measured in decalin at 135° C., of 10 to 50 dl/g.
Claim 2
Dependent Claim
222 words
A polyethylene composition characterized in that: (1) said composition is produced by a multistage polymerization process in which in the presence of a Ziegler-type catalyst formed from (A) a highly active titanium catalyst component comprising magnesium, titanium and halogen as essential components and (B) an organoaluminum compound catalyst component, ethylene or ethylene and a small amount of an alpha-olefin are polymerized in at least one polymerization step to form ultrahigh-molecular-weight polyethylene having an intrinsic viscosity of at least 12 dl/g, and ethylene or ethylene and a small amount of an alpha-olefin are polymerized in the presence of hydrogen in another.polymerization step to form low-molecular-weight to high-molecular-weight polyethylene having an intrinsic viscosity of 0.1 to 5 dl/g, (2) said ultrahigh-molecular-weight polyethylene has an intrinsic viscosity, measured in decalin at 135° C., of at least 12 dl/g, and said low-molecular-weight to high-molecular-weight polyethylene has an intrinsic viscosity, measured in decalin at 135° C., of 0.1 to 5 dl/g, (3) the proportion of said ultrahigh-molecular-weight polyethylene is in the range of 20 to 95% by weight based on the total weight of said ultrahigh-molecular-weight polyethylene and said low-molecular-weight to high-molecular-weight polyethylene, and (4) said polyethylene composition consists substantially of said ultrahigh-molecular-weight polyethylene and said low-molecular-weight to high-molecular-weight polyethylene and has an intrinsic viscosity [η]c, measured in decalin at 135° C., of 10 to 50 dl/g.
Claim 3
Dependent Claim
20 words
The composition set forth in claim 1 wherein the intrinsic viscosity of the ultrahigh-molecular-weight polyethylene is at least 15 dl/g.
Claim 4
Dependent Claim
20 words
The composition set forth in claim 1 wherein the intrinsic viscosity of the ultrahigh-molecular-weight polyethylene is 20 to 55 dl/g.
Claim 5
Dependent Claim
22 words
The composition set forth in claim 1 wherein the intrinsic viscosity of the low-molecular-weight to high-molecular-weight polyethylene is 0.2 to 4.5 dl/g.
Claim 6
Dependent Claim
31 words
The composition set forth in claim 1 wherein the ultrahigh-molecular-weight polyethylene occupies 25 to 80% by weight of the total weight of the ultrahigh-molecular-weight polyethylene and the low-molecular-weight to high-molecular-weight polyethylene.
Claim 7
Dependent Claim
17 words
The composition set forth in claim 1 which has an intrinsic viscosity of 13 to 30 dl/g.
Claim 8
Dependent Claim
32 words
The composition set forth in claim 1 which has a melting torque (T) of not more than 30 kg-cm, and in which T and the intrinsic viscosity [η]c have the relation T≦[η]c.
Claim 9
Dependent Claim
32 words
The composition set forth in claim 1 which has a melting torque (T) of not more than 24 kg-cm, and in which T and the intrinsic viscosity [η]c have the relation T≦0.8x[η]c.
References Cited (Backward Citations)
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US4336352A
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JPS57177036A
Cited
JPS588712A
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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) | 1991-12-20 | 1992-06-20 | 1992-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-20 | 1996-06-20 | 1996-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-20 | 2000-06-20 | 2000-12-20 | $7700.00 | Window Closed / Lapsed |