US4152389A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing a lightweight visually uniform abrasion-resistant nonwoven sheet
Assignee: EIDP Inc
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Filing: 1975-12-22
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Granted: 1979-05-01
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Expires: 1995-12-22
Abstract
Abstract A method for improving the uniformity in visual appearance of a film-fibril nonwoven sheet of thermoplastic polymer comprising passing said sheet through the nip formed between two rolls, one of which has a hot conductive surface with a specified pattern of bosses and the other of which has a surface with a durometer hardness of at least 70 (Shore D scale); applying a specified pressure to the sheet while heating the pattern areas to fuse the film-fibrils together on the surface of the sheet to form transparent windows in the pattern areas without substantially fusing the film-fibrils in the remaining areas of the sheet.
Inventors
- 👤 Philip E. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:06
CPC Classifications
D; D04; D04H; D04H3/00; D04H3/08; D04H3/16; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/24479; Y10T428/24802; Y10T428/24826; Y10T428/27
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
177 words
A method for improving uniformity in visual appearance of a film-fibril nonwoven sheet of thermoplastic polymer comprising passing said sheet through the nip formed between two rolls, one of which has a hot conductive surface with 50-1000 hard bosses per square inch which extend from the surface of the roll to a height of at least 1.2X the thickness of the sheet to be treated, the bosses having a total cross-sectional area measured at their tips sufficient to provide pattern areas equal to 3 to 25% of the area of the sheet, the opposite roll having a surface with a durometer hardness of at least 70 (Shore D scale), applying pressure to the sheet at the nip equal to at least 5 pounds per lineal inch per unit % pattern area while heating the pattern areas to fuse the film-fibrils together on the surface areas of the sheet to form transparent windows in the pattern areas having an average optical transmission of at least 50% without substantially fusing the film-fibrils in the remaining area of the sheet.
Claim 2
Independent Claim
177 words
A method for improving uniformity in visual appearance of a film-fibril nonwoven sheet of thermoplastic polymer comprising passing said sheet through the nip formed between two rolls, one of which has a hot conductive surface with 50-1000 hard bosses per square inch which extend from the surface of the roll to a height of at least 1.2X the thickness of the sheet to be treated, the bosses having a total cross-sectional area measured at their tips sufficient to provide pattern areas equal to 3 to 25% of the area of the sheet, the opposite roll having a surface with a durometer hardness of at least 70 (Shore D scale), applying pressure to the sheet at the nip equal to at least 5 pounds per lineal inch per unit % pattern area while heating the pattern areas to fuse the film-fibrils together on the surface areas of the sheet to form transparent windows in the pattern areas having an average optical transmission of at least 50% without substantially fusing the film-fibrils in the remaining area of the sheet.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein the sheet has a basis weight of from 0.3 to 1.3 oz/yd 2 .
Claim 4
Dependent Claim
20 words
The method of claim 1 wherein the sheet has a basis weight of from 0.6 to 1.15 oz/yd 2 .
Claim 5
Dependent Claim
31 words
The method of claim 1 wherein the heat treatment is carried out at a temperature of at least about 30° to 40° C. above the melting point of the thermoplastic sheet.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein the thermoplastic sheet is polyethylene.
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) | 1982-04-30 | 1982-10-30 | 1983-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-30 | 1986-10-30 | 1987-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-30 | 1990-10-30 | 1991-05-01 | $7700.00 | Window Closed / Lapsed |