US3669931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyethylene terephthalate films containing hydrated aluminum silicate for less shrinkage and abrasion
Assignee: Celanese Corp
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Filing: 1970-07-07
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Granted: 1972-06-13
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Expires: 1990-07-07
Abstract
Abstract A polyethylene terephthalate film is produced having improved abrasion resistance and low shrinkage properties by the dispersing in the film of hydrated aluminum silicate. The improved film has a coefficient of friction in the range of 0.3 to about 1.0 and the hydrated silica ranges from 0.01 percent to about 0.5 percent by weight of the polymer and has a particle size from about 300 to 1000 millimicrons. The film has an intrinsic viscosity of 0.2 to about 1.0 and after biaxially stretching is heated at 215* C. - 235* C. for a period of time to complete crystallization.
Inventors
- 👤 Darrell D Annis
- 👤 Keith D Dodson
- 👤 Paul M Sykes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:44
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/34; C08K3/346
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
21 words
The method of claim 1 wherein the film is biaxially stretched from about 2.5 to about 4.0 times its original dimensions.
Claim 2
Dependent Claim
28 words
The method of claim 2 wherein the hydrated aluminum silicate as dispersed ranges in amounts from about 0.05 to about 0.3 percent by weight of the total polymer.
Claim 3
Dependent Claim
22 words
The method of claim 3 wherein the intrinsic viscosity of the polymer ranges from about 0.4 to about 1.0 deciliters per gram.
Claim 4
Dependent Claim
23 words
The method of claim 4 wherein the average particle size of the hydrated aluminum silicate ranges from about 400 to about 600 millimicrons.
Claim 5
Dependent Claim
15 words
A biaxially oriented polyethylene terephthalate film made in accordance with the process of claim 1.
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) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |