Patent US4842794A successfully refreshed from Google Patents.
US4842794A
Expired / Lapsed
US
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Method of making apertured films and net like fabrics
Assignee: Provident National Bank
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Filing: 1987-07-30
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Granted: 1989-06-27
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Expires: 2007-07-30
Abstract
Abstract A method of making apertured films including the step of perforating films of thermoplastic materials with embossing rolls engraved with patterns which form small slits or incipient slits in the sheet. The patterns are such that the design on the roll includes lands, or raised areas, which cross lands of the opposing roll at an acute angle. The perforated or partially perforated film formed may then be further processed by orientation, uniaxial or biaxial, simultaneous or sequential; by heat treatment; or both to modify the porosity, hole size, or other properties as desired.
Inventors
- 👤 Edward E. Hovis
- 👤 Eric D. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:02
CPC Classifications
B; B29; B29D; B29D28/00; Y; Y10; Y10S; Y10S264/00; Y10S264/47; Y10S264/70; Y10S264/81
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
113 words
A process for the preparation of an apertured thermoplastic film comprising the steps of (a) extruding a molten thermoplastic polymer film between 0.5 and 20 mils thick; and (b) providing the extruded molten polymer film with a multiplicity of small slits by passing the film through the nip of two rollers engraved with patterns containing edges of lands such that the edges cross each other such that the angle formed by the crossing edges is between 15° and 75° with the slits being formed by the edges of the lands at their intersections cutting through the film and with the slits being arranged in patterns having from 10 to 150 slits per inch.
Claim 2
Dependent Claim
113 words
A process for the preparation of an apertured thermoplastic film comprising the steps of (a) extruding a molten thermoplastic polymer film between 0.5 and 20 mils thick; and (b) providing the extruded molten polymer film with a multiplicity of small slits by passing the film through the nip of two rollers engraved with patterns containing edges of lands such that the edges cross each other such that the angle formed by the crossing edges is between 15° and 75° with the slits being formed by the edges of the lands at their intersections cutting through the film and with the slits being arranged in patterns having from 10 to 150 slits per inch.
Claim 3
Dependent Claim
21 words
The process of claim 1 wherein the edges of the lands cross each other at an angle between 30° and 60°.
Claim 4
Dependent Claim
19 words
The process of claim 1 wherein the edges of the lands cross each other at an angle of 45°.
Claim 5
Dependent Claim
26 words
The process of claim 1 including the step of (c) enlarging the slits to form holes of the apertured film to create a net like structure.
Claim 6
Dependent Claim
18 words
The process of claim 4 where step (c) is uniaxially orienting the apertured film from 0 to 500%.
Claim 7
Dependent Claim
47 words
The process of claim 4 where step (c) is sequential biaxial oriention of the structure by stretching in the machine direction from 0% to 600%; then stretching in the cross machine direction from 0% to 600% and then stretching in the machine direction from 0% to 600%.
Claim 8
Dependent Claim
23 words
The process of claim 4 where step (c) is simultaneous biaxial orientation of the apertured film from 0% to 600% in both directions.
Claim 9
Dependent Claim
53 words
The process of claim 4 where step (c) is heat treating the apertured film by restraining the film in both the machine and cross directions to create dimensional changes of less than 20%, and heating the apertured film sufficiently close to its melting point such that oval holes are formed in the structure.
Claim 10
Dependent Claim
62 words
The process of claim 4 where step (c) is a combination of uniaxially orienting the film from 0% to 500% followed by heat treatment of the film by restraining the film in both the machine and cross directions to create dimensional changes of less than 20%, and heating the film sufficiently close to its melting point such that oval holes are formed.
Claim 11
Dependent Claim
25 words
The process of claim 4 where step (c) is a combination of sequentially biaxially orienting the film - followed by heat treatment of the film.
Claim 12
Dependent Claim
19 words
The process of claim 4 where step (c) is a combination of simultaneous biaxial orientation followed by heat treatment.
Claim 13
Dependent Claim
15 words
The process of claim 4 including the step of micro texturizing the net like structure.
Claim 14
Dependent Claim
15 words
The process of claim 4 including the step of macro texturizing the net like structure.
Claim 15
Dependent Claim
43 words
The process of claim 1 wherein the apertured thermoplastic film is selected from the group consisting of high density polyethylene (HDPE), polymer blends in which high density polyethylene is the major component, high density polyethylene and HDPE blends containing pigments, fillers, or additives.
Claim 16
Dependent Claim
43 words
The process of claim 4 wherein the apertured thermoplastic film is selected from the group consisting of high density polyethylene (HDPE), polymer blends in which high density polyethylene is the major component, high density polyethylene and HDPE blends containing pigments, fillers, or additives.
Claim 17
Dependent Claim
50 words
The process of claim 1 wherein the apertured thermoplastic film is selected from the group consisting of polypropylene homopolymers, copolymers or terpolymers or blends of polymers in which the major component is polypropylene homopolymer, copolymer, or terpolymer or the above metioned polymers and polymer blends containing pigments, fillers or additives.
Claim 18
Dependent Claim
50 words
The process of claim 4 wherein the apertured thermoplastic film is selected from the group consisting of polypropylene homopolymers, copolymers or terpolymers or blends of polymers in which the major component is polypropylene homopolymer, copolymer, or terpolymer or the above mentioned polymers and polymer blends containing pigments, fillers or additives.
Claim 19
Dependent Claim
58 words
The process of claim 1 wherein the apertured thermoplastic film is selected from the group consisting of low or medium density polyethylene, linear low density polyethylene, very low density polyethylene or blends of polymers in which the major component is LDPE, MDPE, LLDPE or VLDPE or the above metioned polymers and polymer blends containing pigments, fillers or additives.
Claim 20
Dependent Claim
58 words
The process of claim 4 wherein the apertured thermoplastic film is selected from the group consisting of low or medium density polyethylene, linear low density polyethylene, very low density polyethylene or blends of polymers in which the major component is LDPE, MDPE, LLDPE or VLDPE or the above mentioned polymers and polymer blends containing pigments, fillers or additives.
Claim 21
Dependent Claim
53 words
The process of claim 1 wherein the apertured thermoplastic film is selected from the group consisting of ethylene copolymers including EVA, EEA, EMA, and an ionomer resin or polymer blends containing one or more ethylene copolymers as the major constituent or the above mentioned polymers and polymer blends containing pigments, fillers, or additives.
Claim 22
Dependent Claim
52 words
The process of claim 4 wherein the apertured thermoplastic film is selected from the group consisting of ethylene copolymers including EVA, EEA, EMA, an ionomer resin or polymer blends containing one or more ethylene copolymers as the major constituent or the above mentioned polymers and polymer blends containing pigments, fillers, or additives.
Claim 23
Dependent Claim
54 words
The process of claim 1 wherein the apertured thermoplastic film is selected from the group consisting of polyurethane, thermoplastic elastomer, polyether block amide, polybutene, polyester, and polyamide or polymer blends containing one or more of these polymers as the major constituent or the above mentioned polymers and polymer blends containing pigments, fillers, or additives.
Claim 24
Dependent Claim
52 words
The process of claim 4 wherein the apertured thermoplastic film is selected from the group consisting of polyurethane, thermoplastic elastomer, polyether block amide, polybutene, polyester, and polyamide blends containing one or more of these polymers as the major constituent or the above mentioned polymers and polymer blends containing pigments, fillers, or additives.
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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) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |