US3944699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Opaque molecularly oriented and heat set linear polyester film and process for making same
Assignee: Imperial Chemical Industries Ltd
•
Filing: 1973-10-19
•
Granted: 1976-03-16
•
Expires: 1993-10-19
Abstract
Abstract Opaque voided films having a total luminous transmission not exceeding 25% are made from blends of a polyester preferably polyethylene terephthalate, with 3 to 27% of an ethylene or propylene polymer, prepared by dry blending. One end use of the film, as a base for photographic prints is also described.
Inventors
- 👤 Carl Fraser Mathews
- 👤 Christopher Deverell
- 👤 Gordon Edmund Alfred Pears
- 👤 Peter George Knowles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:07
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; C08J2367/00; C08J2367/02; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786; Y10T428/31797
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
100 words
A process for the production of an opaque molecularly oriented and heat set linear polyester film, which comprises forming a loosely blended mixture of particles of a linear polyester produced by condensing at least one dicarboxylic acid, a lower alkyl diester thereof or bis-p-carboxyphenoxyethane with at least one glycol with from 3 to 27% by weight of particles of a homopolymer of ethylene or propylene, there being no intimate bond between the polyester and homopolymer, extruding the blended mixture as a film, quenching and biaxially orienting the film by stretching it in mutually perpendicular directions, and heat setting the film.
Claim 2
Dependent Claim
100 words
A process for the production of an opaque molecularly oriented and heat set linear polyester film, which comprises forming a loosely blended mixture of particles of a linear polyester produced by condensing at least one dicarboxylic acid, a lower alkyl diester thereof or bis-p-carboxyphenoxyethane with at least one glycol with from 3 to 27% by weight of particles of a homopolymer of ethylene or propylene, there being no intimate bond between the polyester and homopolymer, extruding the blended mixture as a film, quenching and biaxially orienting the film by stretching it in mutually perpendicular directions, and heat setting the film.
Claim 3
Dependent Claim
14 words
A process according to claim 1, in which the linear polyester is polyethylene terephthalate.
Claim 4
Dependent Claim
18 words
A process according to claim 1, in which the blended mixture is formed with a homopolymer of propylene.
Claim 5
Dependent Claim
21 words
A process according to claim 1, in which the homopolymer is present in an amount of up to 20% by weight.
Claim 6
Dependent Claim
16 words
A process according to claim 1, in which the heat setting temperature is up to 200°C.
Claim 7
Dependent Claim
83 words
An opaque molecularly oriented and heat set linear polyester film produced from a blend of particles of a linear polyester produced by condensing at least one dicarboxylic acid, a lower alkyl diester thereof or bis-p-carboxyphenoxyethane with at least one glycol and from 3 to 27% by weight of particles of a homopolymer of ethylene or propylene and having a total luminous transmission of up to 30%, the homopolymer being dispersed in the form of discrete particles throughout the oriented and heat set film.
Claim 8
Dependent Claim
83 words
An opaque molecularly oriented and heat set linear polyester film produced from a blend of particles of a linear polyester produced by condensing at least one dicarboxylic acid, a lower alkyl diester thereof or bis-p-carboxyphenoxyethane with at least one glycol and from 3 to 27% by weight of particles of a homopolymer of ethylene or propylene and having a total luminous transmission of up to 30%, the homopolymer being dispersed in the form of discrete particles throughout the oriented and heat set film.
Claim 9
Dependent Claim
23 words
An opaque film according to claim 6, having a thickness of at least 100 μ and a total luminous transmission not exceeding 20%.
Claim 10
Dependent Claim
16 words
An opaque film according to claim 6, having a density in the range 0.7 to 1.20.
Claim 11
Dependent Claim
15 words
An opaque film according to claim 6, in which the linear polyester is polyethylene terephthalate.
Claim 12
Dependent Claim
18 words
An opaque film according to claim 6, in which the blend is formed with a homopolymer of propylene.
Claim 13
Dependent Claim
40 words
The process of claim 1 wherein the polyester and homopolymer are blended together by dry blending powdered or granulated polyester and the homopolymer to obtain said loosely blended mixture wherein there is no intimate bond between the polyester and homopolymer.
Claim 14
Dependent Claim
26 words
The process of claim 1 wherein the polyester and homopolymer are blended together by combining to melt streams of the polyester and homopolymer just before extrusion.
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) | 1979-03-16 | 1979-09-15 | 1980-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-16 | 1983-09-15 | 1984-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-16 | 1987-09-15 | 1988-03-16 | $7700.00 | Window Closed / Lapsed |