US4835219A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyethylene composition
Assignee: Eneos Corp
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Filing: 1987-12-11
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Granted: 1989-05-30
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Expires: 2007-12-11
Abstract
Abstract Disclosed is polyethylene composition having excellent environmental stress cracking resistance (ESCR) and giving molded articles with good surface properties. This composition comprises a blend of two specific types of polyethylene selected with due consideration for their molecular weight distribution in addition to their molecular weights, so that it has excellent melt tension, ESCR and moldability. Accordingly, it can suitably be used in blow molding and extrusion molding to produce molded articles with no shark skin, as well as vessels of very large size. This composition is formed by blending (A) polyethylene obtained according to a two-step polymerization process using a Ziegler catalyst containing magnesium and titanium, and (B) high-molecular-weight polyethylene obtained with the aid of a chromium-containing catalyst, in a specified proportion.
Inventors
- 👤 Yoshio Tajima
- 👤 Kazutosi Nomiyama
- 👤 Yoshiyuki Shimo
- 👤 Nobuyuki Kuroda
- 👤 Kazuo Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:08
CPC Classifications
C; C08; C08F; C08F10/00; C08F10/02; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/06; C08L2205/00; C08L2205/02; C08L2205/025; C08L2308/00; C08L2314/00; C08L2314/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
326 words
A polyethylene composition having a melt index of 0.001 to 1 g/l0 min and a density of 0.940 to 0.960 g/cm 3 , which comprises a blend of (A) 80 to 97% by weight of polyethylene having a density of 0.940 to 0.960 g/cm 3 , an intrinsic viscosity of 2.0 to 5.0 dl/g as measured in decalin at 135° C., and an N value of 2.0 to 3.5, the polyethylene having been obtained by polymerizing ethylene, optionally together with an α-olefin of up to 4 carbon atoms, according to a two-step polymerization process using a Ziegler catalyst containing at least magnesium and titanium, the two-step polymerization process including (a) the first step of carrying out the polymerization at a temperature of 30° to 100° C. in such a way that. polyethylene having an intrinsic viscosity of up to 7.2 dl/g as measured in decalin at 135° C. is formed in an amount of 5 to 70% by weight based on the total amount of the finally obtained polyethylene and (b) the second step of carrying out the polymerization at a temperature of 30° to 100° C. in such a way that polyethylene having an intrinsic viscosity of 0.6 to 1.7 dl/g as measured in decalin at 135° C. is formed in an amount of 95 to 30% by weight based on the total amount of the finally obtained polyethylene, and (B) 20 to 3% by weight of polyethylene having a density of 0.940 to 0.960 g/cm 3 , an intrinsic viscosity of 7.0 to 15.0 dl/g a measured in decalin at 135° C., and an N value of 2.5 to 3.5, the polyethylene having been obtained by polymerizing ethylene with the aid of a catalyst composed of a solid component containing at least chromium trioxide, and a compound of the general formula ##STR5## where R is a hydrocarbon radical of 1 to 18 carbon atoms, and n is a whole number of 2 to 100.
Claim 2
Dependent Claim
326 words
A polyethylene composition having a melt index of 0.001 to 1 g/l0 min and a density of 0.940 to 0.960 g/cm 3 , which comprises a blend of (A) 80 to 97% by weight of polyethylene having a density of 0.940 to 0.960 g/cm 3 , an intrinsic viscosity of 2.0 to 5.0 dl/g as measured in decalin at 135° C., and an N value of 2.0 to 3.5, the polyethylene having been obtained by polymerizing ethylene, optionally together with an α-olefin of up to 4 carbon atoms, according to a two-step polymerization process using a Ziegler catalyst containing at least magnesium and titanium, the two-step polymerization process including (a) the first step of carrying out the polymerization at a temperature of 30° to 100° C. in such a way that. polyethylene having an intrinsic viscosity of up to 7.2 dl/g as measured in decalin at 135° C. is formed in an amount of 5 to 70% by weight based on the total amount of the finally obtained polyethylene and (b) the second step of carrying out the polymerization at a temperature of 30° to 100° C. in such a way that polyethylene having an intrinsic viscosity of 0.6 to 1.7 dl/g as measured in decalin at 135° C. is formed in an amount of 95 to 30% by weight based on the total amount of the finally obtained polyethylene, and (B) 20 to 3% by weight of polyethylene having a density of 0.940 to 0.960 g/cm 3 , an intrinsic viscosity of 7.0 to 15.0 dl/g a measured in decalin at 135° C., and an N value of 2.5 to 3.5, the polyethylene having been obtained by polymerizing ethylene with the aid of a catalyst composed of a solid component containing at least chromium trioxide, and a compound of the general formula ##STR5## where R is a hydrocarbon radical of 1 to 18 carbon atoms, and n is a whole number of 2 to 100.
Claim 3
Dependent Claim
17 words
The polyethylene composition of claim 1 wherein component (A) has an N value of 2.2 to 3.5.
Claim 4
Dependent Claim
17 words
The polyethylene composition of claim 1 wherein component (B) has an N value of 2.7 to 3.5.
Claim 5
Dependent Claim
18 words
The polyethylene composition of claim 1 wherein component (A) has an intrinsic viscosity of 2.5 to 4.5 dl/g.
Claim 6
Dependent Claim
18 words
The polyethylene composition of claim 1 wherein component (B) has an intrinsic viscosity of 7.0 to 12 dl/g.
Claim 7
Dependent Claim
26 words
The polyethylene composition of claim 1 wherein 90 to 5% by weight of component (A) is blended with 10 to 5% by weight of component (B).
Claim 8
Dependent Claim
60 words
The polyethylene composition of claim 1 wherein component (B) has been obtained by polymerizing ethylene with the aid of a catalyst containing a compound of the general formula ##STR6## where R is a hydrocarbon radical of 1 to 18 carbon atoms, Z and Z' are hydrogen atoms or R radicals, and n is a whole number of 2 to 100.
Claim 9
Dependent Claim
47 words
The polyethylene composition of claim 1 wherein component obtained by polymerizing ethylene with the aid of a catalyst containing a compound of the general formula (AlRO).sub.n where is a hydrocarbon radical of 1 to 18 carbon atoms, and n is a whole number of 3 to 100.
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) | 1992-05-29 | 1992-11-28 | 1993-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-29 | 1996-11-28 | 1997-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-29 | 2000-11-28 | 2001-05-30 | $7700.00 | Window Closed / Lapsed |