Patent US4786687A successfully refreshed from Google Patents.
US4786687A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Molding composition
Assignee: Eneos Corp
•
Filing: 1986-04-21
•
Granted: 1988-11-22
•
Expires: 2006-04-21
Abstract
Abstract A molding composition is disclosed which comprises ultrahigh molecular weight polyethylene having an intrinsic viscosity of 10-30 dl/g at 135 DEG C. in decalin. Improved injection moldability is provided by the use of such polyethylene obtainable by a multi-stage polymerization reaction including at least the following two stages: (a) a first stage in which ethylene is polymerized using a specified composite catalyst in the absence of hydrogen of its presence at lower concentration to produce 50-99.5 weight parts of polyethylene having an intrinsic viscosity of 12-32 dl/g at 135 DEG C. in decalin; and (b) a second stage in which a fresh feed of ethylene is polymerized in the presence of hydrogen at higher concentration to produce 50-0.5 weight parts of polyethylene having an intrinsic viscosity of 0.1-5 dl/g at 135 DEG C. in decalin.
Inventors
- 👤 Akira Sano
- 👤 Masataka Oka
- 👤 Tetsujirou Kuroishi
- 👤 Kazuo Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:42
CPC Classifications
C; C08; C08F; C08F10/00; C08F10/02; Y; Y10; Y10S; Y10S526/00; Y10S526/903; Y10S526/905
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
177 words
An injection molding composition comprising an ultrahigh molecular weight polyethylene material having an intrinsic viscosity of 10-30 dl/g at 135° C. in decalin, said material resulting from a polymerization process consisting of the following two stages of polymerization reaction: (a) a first reaction stage wherein an ethylene monomer is polymerized in a reaction vessel in the presence of a composite catalyst comprising a solid component containing at least magnesium, titanium and/or vanadium and an organometallic compound and in the absence of hydrogen or in the presence of hydrogen at a low concentration to produce 75-99 parts by weight of polyethylene having an intrinsic viscosity of 12-32 dl/g at 135° C. in decalin; and (b) a second reaction stage wherein a fresh feed of ethylene monomer is introduced in the same reaction vessel and polymerized in the presence of hydrogen at a higher concentration while retaining the reaction produce from the first reaction stage in said reaction vessel to produce 25-1 parts by weight of polyethylene having an intrinsic viscosity of 0.1-5 dl/g at 135° C. in decalin.
Claim 2
Dependent Claim
177 words
An injection molding composition comprising an ultrahigh molecular weight polyethylene material having an intrinsic viscosity of 10-30 dl/g at 135° C. in decalin, said material resulting from a polymerization process consisting of the following two stages of polymerization reaction: (a) a first reaction stage wherein an ethylene monomer is polymerized in a reaction vessel in the presence of a composite catalyst comprising a solid component containing at least magnesium, titanium and/or vanadium and an organometallic compound and in the absence of hydrogen or in the presence of hydrogen at a low concentration to produce 75-99 parts by weight of polyethylene having an intrinsic viscosity of 12-32 dl/g at 135° C. in decalin; and (b) a second reaction stage wherein a fresh feed of ethylene monomer is introduced in the same reaction vessel and polymerized in the presence of hydrogen at a higher concentration while retaining the reaction produce from the first reaction stage in said reaction vessel to produce 25-1 parts by weight of polyethylene having an intrinsic viscosity of 0.1-5 dl/g at 135° C. in decalin.
Claim 3
Dependent Claim
28 words
The composition according to claim 1 wherein the hydrogen concentration is 0-10 mol percent in the first reaction stage and 35-95 mol percent in the second direction stage.
References Cited (Backward Citations)
US3969470A
Cited
US4311752A
Cited
US4336352A
Cited
JPS57177036A
Cited
US4461873A
Cited
JPS59126466A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |