Patent US4477502A successfully refreshed from Google Patents.
US4477502A
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Plastic sheet having high gloss and low coefficient of friction and method for producing the same
Assignee: Rexam Beverage Can Co
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Filing: 1983-04-29
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Granted: 1984-10-16
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Expires: 2003-04-29
Abstract
Abstract A plastic sheet (13) having a surface with low friction and high gloss is produced by extruding a layer of thermoplastic and pressing it while hot against the surface of a chill roller (17). The surface of the chill roller (17) is characterized by being highly polished and having minute randomly distributed depressions therein of an average depth of about 5 microns, a depth standard deviation of less than 3 microns, and an average frequency of about 3,000 per square centimeter. The thermoplastic layer may be laminated to a single or multilayer base (12) to form a finished product (21). A polyethylene surface layer will have a coefficient of friction generally less than 1.0 with respect to itself, while the surface nonetheless retains a high gloss appearance.
Inventors
- 👤 Eileen F. O'Sullivan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:16
CPC Classifications
B; B32; B32B; B32B38/00; B32B38/06; B29; B29C; B29C53/00; B29C53/36; B29C53/38; B29C53/382; B29C59/00; B29C59/02; B29C59/022; B29C59/04; B29C59/046; B32B37/00; B32B37/14; B32B37/15; B32B37/153; B65; B65D; B65D35/00; B65D35/02; B29C2059/023; B29K; B29K2023/00; B29K2995/00; B29K2995/0018; B29K2995/0022; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1007; Y10T156/1008; Y10T156/1013; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1355; Y10T428/1379; Y10T428/24; Y10T428/24355; Y10T428/24628; Y10T428/24669; Y10T428/26
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
90 words
A plastic sheet having a high gloss and low coefficient of friction surface comprising a layer of thermoplastic material with a smooth surface interrupted by randomly distributed prominences having an average area of less than 16,000 square microns, an average height of about 5 microns, a standard deviation of the height of the prominences about the average of less than 3 microns, and an average frequency of the prominences over the surface of the sheet of 3,000 per square centimeter, the prominences being substantially convex and rounded about their peripheries.
Claim 2
Dependent Claim
90 words
A plastic sheet having a high gloss and low coefficient of friction surface comprising a layer of thermoplastic material with a smooth surface interrupted by randomly distributed prominences having an average area of less than 16,000 square microns, an average height of about 5 microns, a standard deviation of the height of the prominences about the average of less than 3 microns, and an average frequency of the prominences over the surface of the sheet of 3,000 per square centimeter, the prominences being substantially convex and rounded about their peripheries.
Claim 3
Dependent Claim
41 words
The plastic sheet of claim 1 wherein the thermoplastic material is polyethylene and wherein the surface of the sheet has a face-to-face coefficient of friction of 1.0 or less and has a gloss, TAPPI 20° angle, from 60 to 70 units.
Claim 4
Dependent Claim
82 words
A container having a layer as the outermost layer comprising a plastic material having a smooth surface interrupted by randomly distributed prominences having an average area of less than 16,000 square microns, an average height of about 5 microns, a standard deviation of the height of the prominences about the average of less than 3 microns, and an average frequency of the prominences over the surface of about 3,000 per square centimeter, the prominences being substantially convex and rounded about their peripheries.
Claim 5
Dependent Claim
82 words
A container having a layer as the outermost layer comprising a plastic material having a smooth surface interrupted by randomly distributed prominences having an average area of less than 16,000 square microns, an average height of about 5 microns, a standard deviation of the height of the prominences about the average of less than 3 microns, and an average frequency of the prominences over the surface of about 3,000 per square centimeter, the prominences being substantially convex and rounded about their peripheries.
Claim 6
Dependent Claim
38 words
The container of claim 3, wherein the plastic material is polyethylene and wherein the surface thereof has a face-to-face coefficient of friction of 1.0 or less and has a gloss, TAPPI 20° angle, from 60 to 70 units.
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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) | 1987-10-16 | 1988-04-16 | 1988-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-16 | 1992-04-16 | 1992-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-16 | 1996-04-16 | 1996-10-16 | $7700.00 | Window Closed / Lapsed |