Patent US1205384A successfully refreshed from Google Patents.
Patent US3875284A successfully refreshed from Google Patents.
US3875284A
Expired / Lapsed
US
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Process for preparing clear polyoxymethylene film
Assignee: Asahi Kasei Corp
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Filing: 1972-09-25
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Granted: 1975-04-01
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Expires: 1992-09-25
Abstract
Abstract A clear crystalline polyoxymethylene film prepared by the process comprising preheating the film to a temperature not lower than 20*C. below a temperature within the range from that at which polyoxymethylene crystals begin to melt to that at which polyoxymethylene crystals finish melting, and rolling the preheated film to a thickness not greater than 95 percent of the original thickness through heated pressing rollers while maintaining the temperature of the film within the aforementioned range and simultaneously or immediately stretching the thus rolled film to such an extent that the thickness of the stretched film is reduced from 1/1.2 to 1/6 of the original thickness.
Inventors
- 👤 Kiichiro Sasaguri
- 👤 Takeo Yuasa
- 👤 Kazuhiko Shimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:50
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/005; B29C55/02; B29K; B29K2059/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
135 words
THE PROCESS FOR PREPARING CLEAR POLYOXMETHYLENE FILM INCLUDING THE STEP OF PASSING SAID FILM THROUGH HEATED PRESSING ROLLERS MAINTAINED AT A TEMPERATURE WITHIN THE RANGE FROM THE AT WHICH THE POLYOXYMETHYLENE CRYSTALS BEGIN TO MELT TO THAT AT WHICH SAID CRYSTALS FINISH MELTING WHICH COMPRISES: A. PREHEATING THE FILM AT A TEMPERATURE NOT LOWER THAN 20*C. BELOW THE TEMPERATURE OF SAID PRESSING ROLLERS AND NOT HIGHER THAN THE TEMPERATURE OF SAID PRESSING ROLLERS; B. ROLLING THE PREHEATED FILM TO A THICKNESS NOT GREATER THAN 95 PERCENT OF THE ORIGINAL THICKNESS THROUGH SAID HEATED PRESSING ROLLERS WHILE MAINTAINING THE TEMPERATURE OF THE FILM WITHIN SAID RANGE; AND C. SIMULTANEOUSLY STRETCHING THE FILM THUS ROLLED TO SUCH AN EXTENT THAT THE THICKNESS OF THE STRETCHED FILM IS REDUCED TO FROM 1/1.2 TO 1/6 OF THE ORIGINAL THICKNESS.
Claim 2
Dependent Claim
135 words
THE PROCESS FOR PREPARING CLEAR POLYOXMETHYLENE FILM INCLUDING THE STEP OF PASSING SAID FILM THROUGH HEATED PRESSING ROLLERS MAINTAINED AT A TEMPERATURE WITHIN THE RANGE FROM THE AT WHICH THE POLYOXYMETHYLENE CRYSTALS BEGIN TO MELT TO THAT AT WHICH SAID CRYSTALS FINISH MELTING WHICH COMPRISES: A. PREHEATING THE FILM AT A TEMPERATURE NOT LOWER THAN 20*C. BELOW THE TEMPERATURE OF SAID PRESSING ROLLERS AND NOT HIGHER THAN THE TEMPERATURE OF SAID PRESSING ROLLERS; B. ROLLING THE PREHEATED FILM TO A THICKNESS NOT GREATER THAN 95 PERCENT OF THE ORIGINAL THICKNESS THROUGH SAID HEATED PRESSING ROLLERS WHILE MAINTAINING THE TEMPERATURE OF THE FILM WITHIN SAID RANGE; AND C. SIMULTANEOUSLY STRETCHING THE FILM THUS ROLLED TO SUCH AN EXTENT THAT THE THICKNESS OF THE STRETCHED FILM IS REDUCED TO FROM 1/1.2 TO 1/6 OF THE ORIGINAL THICKNESS.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the intrinsic viscosity of said polyoxymethylene is from about 0.9 to 2.7.
Claim 4
Dependent Claim
23 words
The process of claim 1 wherien the intrinsic viscosity of the polyoxymethylene is 1.75 and said temperature range is between k160*C and 174*C.
Claim 5
Dependent Claim
23 words
The process of claim 1 wherein the intrinsic viscosity of the polyoxymethylene is 1.35 and said temperature range is between 158*C to 175*C.
Claim 6
Dependent Claim
23 words
The process of claim 1 wherien the intrinsic viscosity of the polyoxymethylene is 2.2 and said temperatuare range is between 155*C and 170*C.
Claim 7
Dependent Claim
24 words
The process of claim 1 wherein the preheating temperature of the film is further determined in accordance with the thickness and velocity of rolling.
Claim 8
Dependent Claim
31 words
The process of claim 1 wherein the rolling pressure is determined in accordance with the number of size of the spherulites present in the film and the thickness of the film.
Claim 9
Dependent Claim
14 words
The process of claim 1 wherein the film is stretched in two perpendicular directions.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |