US3876740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for improving interior surface smoothness and gloss in foamed tubular extrudates by the use of extrusion die faces of novel geometry
Assignee: Standard Oil Co
•
Filing: 1972-10-27
•
Granted: 1975-04-08
•
Expires: 1992-10-27
Abstract
Abstract Apparatus and method for reducing interior surface roughness and improving interior surface gloss in extruded tubular articles made from foamed thermoplastic materials.
Inventors
- 👤 Ernst Egli
- 👤 Larry A Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:17
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/50; B29C44/507; B29L; B29L2023/00; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
66 words
A PROCESS FOR MAKING A TUBULAR ARTICLES OF IMPROVED INTERIOR WALL SMOOTHNESS WHICH COMPRISES EXTRUDING A HEATED MIXTURE OF POLYSTYRENE AND A BLOWING AGENT UNDER PRESSURE THROUGH AN ANNULAR OPENING OF AN EXTRUSION DIE WHEREIN SAID DIE IS COMPOSED OF AN INNER PORTION AND AN OUTER PORTION TOGETHER FORMING SAID ANNULAR OPENING, SAID INNER PORTION BEING RECESSED FROM EXIT FACE OF SAID DIE, AND WHEREIN THE
Claim 2
Dependent Claim
66 words
A PROCESS FOR MAKING A TUBULAR ARTICLES OF IMPROVED INTERIOR WALL SMOOTHNESS WHICH COMPRISES EXTRUDING A HEATED MIXTURE OF POLYSTYRENE AND A BLOWING AGENT UNDER PRESSURE THROUGH AN ANNULAR OPENING OF AN EXTRUSION DIE WHEREIN SAID DIE IS COMPOSED OF AN INNER PORTION AND AN OUTER PORTION TOGETHER FORMING SAID ANNULAR OPENING, SAID INNER PORTION BEING RECESSED FROM EXIT FACE OF SAID DIE, AND WHEREIN THE
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein said tapered projection ends in a land.
Claim 4
Dependent Claim
17 words
The process of claim 2 wherein said land is in size equal to the amount of recess.
Claim 5
Dependent Claim
15 words
The process of claim 3 wherein said land and amount of recess are 0.05 inches.
Claim 6
Dependent Claim
108 words
A process for making a tubular article of improved interior wall smoothness which comprises extruding a heated mixture of polyvinyl chloride and a blowing agent under pressure through an annular opening of an extrusion die wherein said die is composed of an inner portion and and outer portion together forming said annular opening, said outer portion being recessed from the exit face of said die, and wherein the orifice of said annular opening contains a restriction formed on said outer portion comprising a tapered projection which extends radially into said annular opening so that said orifice is of reduced cross-section relative to the remainder of said annular opening.
Claim 7
Dependent Claim
108 words
A process for making a tubular article of improved interior wall smoothness which comprises extruding a heated mixture of polyvinyl chloride and a blowing agent under pressure through an annular opening of an extrusion die wherein said die is composed of an inner portion and and outer portion together forming said annular opening, said outer portion being recessed from the exit face of said die, and wherein the orifice of said annular opening contains a restriction formed on said outer portion comprising a tapered projection which extends radially into said annular opening so that said orifice is of reduced cross-section relative to the remainder of said annular opening.
Claim 8
Dependent Claim
13 words
The process of claim 5 wherein said tapered projection ends in a land.
Claim 9
Dependent Claim
17 words
The process of claim 6 wherein said land is in size equal to the amount of recess.
Claim 10
Dependent Claim
15 words
The process of claim 7 wherein said land and amount of recess are 0.25 inches.
References Cited (Backward Citations)
US1598201A
Cited
US3281513A
Cited
US3304580A
Cited
US3299192A
Cited
US3391051A
Cited
US3308509A
Cited
US3488746A
Cited
US3677676A
Cited
US3525125A
Cited
US3803278A
Cited
US3790326A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |