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US3968091A
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Low melt index ethylene-vinyl acetate copolymers
Assignee: Millennium Petrochemicals Inc
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Filing: 1973-07-23
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Granted: 1976-07-06
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Expires: 1993-07-23
Abstract
Abstract The melt index of ethylene-vinyl acetate copolymers is decreased by mechanically working the preformed copolymers.
Inventors
- 👤 Claude J. Stiles
- 👤 Byford P. Hancock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:20
CPC Classifications
C; C08; C08J; C08J3/00; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
63 words
A process for decreasing the melt index of preformed ethylene-vinyl acetate copolymers having about 8-55 weight percent vinyl acetate to a level sufficient for extrusion applications which comprises mechanically working a composition consisting essentially of the copolymer, at a peak temperature below the degradation temperature of the copolymer and for a maximum period of residence time at the peak temperature of 5 minutes.
Claim 2
Dependent Claim
63 words
A process for decreasing the melt index of preformed ethylene-vinyl acetate copolymers having about 8-55 weight percent vinyl acetate to a level sufficient for extrusion applications which comprises mechanically working a composition consisting essentially of the copolymer, at a peak temperature below the degradation temperature of the copolymer and for a maximum period of residence time at the peak temperature of 5 minutes.
Claim 3
Dependent Claim
16 words
The process of claim 1 wherein the copolymer contains at least 35 weight percent vinyl acetate.
Claim 4
Dependent Claim
13 words
The process of claim 2 wherein the peak temperature is about 40°-225° C.
Claim 5
Dependent Claim
12 words
The process of claim 3 wherein the residence time is 3-5 minutes.
Claim 6
Dependent Claim
15 words
The process of claim 4 wherein the copolymer contains about 40 weight percent vinyl acetate.
Claim 7
Dependent Claim
43 words
The process of claim 1 which consists essentially of mechanically working a composition consisting of the copolymer at a peak temperature below the degradation temperature of the copolymer and for a maximum period of residence time at the peak temperature of 5 minutes.
Claim 8
Dependent Claim
16 words
The process of claim 6 wherein the copolymer contains at least 35 weight percent vinyl acetate.
Claim 9
Dependent Claim
43 words
The process of claim 1 which consists of mechanically working a composition which consists of the copolymer at a peak temperature below the degradation temperature of the copolymer and for a maximum period of residence time at the peak temperature of 5 minutes.
Claim 10
Dependent Claim
16 words
The process of claim 8 wherein the copolymer contains at least 35 weight percent vinyl acetate.
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) | 1979-07-06 | 1980-01-05 | 1980-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-06 | 1984-01-05 | 1984-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-06 | 1988-01-05 | 1988-07-06 | $7700.00 | Window Closed / Lapsed |