US3981952A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fibrous materials
Assignee: Lambeg Industrial Research Assoc
•
Filing: 1972-07-24
•
Granted: 1976-09-21
•
Expires: 1992-07-24
Abstract
Abstract Disclosed is a process for treating a travelling film made from a molecularly-orientable synthetic thermoplastic organic polymer, according to which the film while in an unoriented condition and a molten deformable state has at least one of its sides modified so as to have a homogeneous series of high frequency discrete protuberances or depressions. This is achieved by subjecting the film to the action of an appropriately contoured surface. The frequency is at least of the order of 100 per inch. The center line average height of the protuberances or depressions is preferably from 1 to 10 microns. The process is advantageously used for making, inter alia, weaving tapes, twine and fibrous materials. Also disclosed is apparatus for carrying out such a process. In a preferred form it comprises an extruder, a pair of nip rollers, at least one of which has an appropriately contoured surface, and a hot drawing means. Also disclosed are versions including slitting means and fibrillating means.
Inventors
- 👤 James Nelson Ruddell
- 👤 Samuel McMeekin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:32
CPC Classifications
B; B29; B29D; B29D28/00; B29C; B29C43/00; B29C43/22; B29C43/224; B29C53/00; B29C53/22; B29C53/24; Y; Y10; Y10S; Y10S264/00; Y10S264/47
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
157 words
A process for treating a travelling film made from a molecularly-orientable synthetic thermoplastic organic polymer which includes the steps of pressing at least one side of the film, while it is in an unoriented condition and a molten deformable state, against a travelling surface in such a way that there is no relative movement between the surface of the film and travelling surface at the point of contact between the two, said travelling surface having, as an integral part thereof, a homogeneous series of high frequency discrete deformations so as to produce a homogeneous series of discrete deformations on said film, the frequency of the deformations being at least 100 per inch measured in every direction along the film surface, thereafter cooling said film to a non-molten state in which said deformations are substantially retained, whereby the tendency of cracks which occur in the film after drawing to propagate is substantially reduced, and subsequently drawing said film.
Claim 2
Dependent Claim
157 words
A process for treating a travelling film made from a molecularly-orientable synthetic thermoplastic organic polymer which includes the steps of pressing at least one side of the film, while it is in an unoriented condition and a molten deformable state, against a travelling surface in such a way that there is no relative movement between the surface of the film and travelling surface at the point of contact between the two, said travelling surface having, as an integral part thereof, a homogeneous series of high frequency discrete deformations so as to produce a homogeneous series of discrete deformations on said film, the frequency of the deformations being at least 100 per inch measured in every direction along the film surface, thereafter cooling said film to a non-molten state in which said deformations are substantially retained, whereby the tendency of cracks which occur in the film after drawing to propagate is substantially reduced, and subsequently drawing said film.
Claim 3
Dependent Claim
22 words
A process as set forth in claim 1 including the further and subsequent step of drawing the film to cause uniaxial orientation.
Claim 4
Dependent Claim
22 words
A process as set forth in claim 1 including the further and subsequent step of drawing the film to cause bi-axial orientation.
Claim 5
Dependent Claim
25 words
A process as set forth in claim 1 including the step of slitting the film, before any drawing step, into a plurality of narrow tapes.
Claim 6
Dependent Claim
24 words
A process as set forth in claim 1 including the step of fibrillating the film by means of a pinned roller or like fibrillator.
Claim 7
Dependent Claim
24 words
A process as set forth in claim 1 in which the frequency of the deformations on the surface is 200 or more per inch.
Claim 8
Dependent Claim
20 words
A process as set forth in claim 1 in which the film is treated as it emerges from an extruder.
Claim 9
Dependent Claim
36 words
A process as set forth in claim 1 in which the film is passed between two rollers which exert a nip pressure thereon, the surface of one or each roller having such a series of deformations.
Claim 10
Dependent Claim
43 words
A process as set forth in claim 1 in which the film is passed between two rollers which exert a nip pressure thereon, the surface of one roller being smooth and the surface of the other roller having such a series of deformations.
Claim 11
Dependent Claim
20 words
A process as set forth in claim 1 in which the said surface is that of an endless travelling band.
Claim 12
Dependent Claim
25 words
A process as set forth in claim 1 in which the transverse dimensions of the deformations are of the order of 0.003 inch or less.
Claim 13
Dependent Claim
19 words
A process as claimed in claim 1 in which the thickness of the film is 0.006 inch or less.
Claim 14
Dependent Claim
25 words
A process as claimed in claim 1 in which the centre line average height of the deformations is within the range 1 to 10 microns.
Claim 15
Dependent Claim
30 words
A process as claimed in claim 1 in which the surface exerts a pressure of between 8 and 90 pounds per inch width of the surface contact with the film.
Claim 16
Dependent Claim
14 words
A process as claimed in claim 1 in which the film is polypropylene film.
Claim 17
Dependent Claim
153 words
A process for treating a traveling film made from a molecularly-orientable synthetic thermoplastic organic polymer which includes the steps of pressing at least one side of the film while it is in an unoriented condition and a molten deformable state, against a travelling surface in such a way that there is no relative movement between the surface of the film and travelling surface at the point of contact between the two, said travelling surface having, as an integral part thereof, a homogenous series of high frequency discrete deformations so as to produce a homogeneous series of discrete deformations on said film, the frequency of the deformations being at least 10,000 per square inch of film surface, thereafter cooling said film to a non-molten state in which said deformations are substantially retained, whereby the tendency of cracks which occur in the film after drawing to propogate is substantially reduced, and subsequently drawing said film.
Claim 18
Dependent Claim
153 words
A process for treating a traveling film made from a molecularly-orientable synthetic thermoplastic organic polymer which includes the steps of pressing at least one side of the film while it is in an unoriented condition and a molten deformable state, against a travelling surface in such a way that there is no relative movement between the surface of the film and travelling surface at the point of contact between the two, said travelling surface having, as an integral part thereof, a homogenous series of high frequency discrete deformations so as to produce a homogeneous series of discrete deformations on said film, the frequency of the deformations being at least 10,000 per square inch of film surface, thereafter cooling said film to a non-molten state in which said deformations are substantially retained, whereby the tendency of cracks which occur in the film after drawing to propogate is substantially reduced, and subsequently drawing said film.
Claim 19
Dependent Claim
24 words
A process as set forth in claim 16 wherein the frequency of the deformations is at least 40,000 per square inch of film surface.
References Cited (Backward Citations)
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US3398220A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-21 | 1980-03-22 | 1980-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-21 | 1984-03-22 | 1984-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-21 | 1988-03-22 | 1988-09-21 | $7700.00 | Window Closed / Lapsed |