US5082616A
Expired / Lapsed
US
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Film blowing process
Assignee: Edison Polymer Innovation Corp
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Filing: 1990-10-25
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Granted: 1992-01-21
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Expires: 2010-10-25
Abstract
Abstract A method for preparing biaxially oriented poly(vinylidene fluoride) films involving the addition of a minor amount of a polymer miscible with PVDF, particularly poly(methyl methacrylate), to the poly(vinylidene fluoride) to form a blend exhibiting reduced crystallinity and reduced rates of crystallization during the film forming process. The low crystallinity permits the blend to be subsequently formed into biaxially oriented film in a double-bubble tubular film extrusion process by retarding the rate of crystallization in the first bubble, thereby permitting formation of the second bubble without rupture. The films thus formed possess piezoelectric and other desirable characteristics.
Inventors
- 👤 James L. White
- 👤 Tao Nie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:09
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C48/00; B29C48/03; B29C48/09; B29C48/10; B29C55/00; B29C55/28; C08L; C08L27/00; C08L27/02; C08L27/12; C08L27/16; B29C48/001; B29C48/0018; B29C48/0019; B29K; B29K2027/00; B29K2027/12; B29K2027/16; B29K2105/00; B29K2105/0088; B29K2995/00; B29K2995/0003; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/16; C08L33/00; C08L33/04; C08L33/06; C08L33/08
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
87 words
A process for forming biaxially oriented film in a tubular film extrusion process from a blend of poly(vinylidene fluoride) and at least one other polymer miscible therewith comprising: extruding said blend from an annular die to form a tubular extrudate; cooling said extrudate and injecting a gas therein to form a first bubble while simultaneously drawing said bubble; collapsing said first bubble; heating said collapsed bubble and injecting a gas therein to form a second bubble while simultaneously drawing said second bubble, thereby forming biaxially oriented film.
Claim 2
Dependent Claim
87 words
A process for forming biaxially oriented film in a tubular film extrusion process from a blend of poly(vinylidene fluoride) and at least one other polymer miscible therewith comprising: extruding said blend from an annular die to form a tubular extrudate; cooling said extrudate and injecting a gas therein to form a first bubble while simultaneously drawing said bubble; collapsing said first bubble; heating said collapsed bubble and injecting a gas therein to form a second bubble while simultaneously drawing said second bubble, thereby forming biaxially oriented film.
Claim 3
Dependent Claim
33 words
A process according to claim 1 wherein said other polymer is a member selected from the group consisting of poly(methyl methacrylate), poly(ethyl methacrylate), poly(methyl acrylate), poly(ethyl acrylate), poly(vinyl acetate), and poly(vinyl methyl ketone).
Claim 4
Dependent Claim
31 words
A process according to claim 1 wherein said other polymer is poly(methyl methacrylate) and said other polymer constitutes from about 15% to about 30%, on a weight basis, of said blend.
Claim 5
Dependent Claim
22 words
A process according to claim 3 wherein said cooling is carried out by contacting said extrudate with a stream of cool air.
Claim 6
Dependent Claim
34 words
A process according to claim 4 wherein said air has a temperature of from about 10° C. to about 20° C., and said air emanates from a cooling ring through which said extrudate passes.
Claim 7
Dependent Claim
23 words
A process according to claim 3 wherein said heating is carried out by contacting said second bubble with a stream of heated air.
Claim 8
Dependent Claim
32 words
A process according to claim 6 wherein said air is heated to from about 100° C. to about 140° C. and emanates from a heating ring through which said second bubble passes.
Claim 9
Dependent Claim
64 words
A process according to claim 3 wherein the draw down ratio of said first bubble is from about 5:1 to about 20:1, and that of said second bubble is from about 1.1:1 to about 3:1, while the blow up ratio of said first bubble is from about 1.5:1 to about 1.75:1, and that of said second bubble is from about 2:1 to about 3.75:1.
Claim 10
Dependent Claim
37 words
A process according to claim 3 in which the weight average molecular weight of said poly(vinylidene fluoride) is from about 330,000 to about 390,000, while that of the poly(methyl methacrylate) is from about 110,000 to about 125,000.
Claim 11
Dependent Claim
121 words
A process for forming biaxially oriented film in a continuous tubular film extrusion process from a blend of poly(vinylidene fluoride) and a second polymer miscible therewith comprising: continuously extruding said blend from an annular die to form a tubular extrudate; cooling said extrudate, and injecting air therein to form a first bubble while simultaneously drawing said bubble along its longitudinal axis; continuously collapsing said bubble with nip rolls; heating said collapsed bubble and injecting air therein to continuously form a second bubble while simultaneously drawing said second bubble, thereby continuously forming biaxially oriented film, wherein said second polymer comprises from about 15% to about 30%, on a weight basis, of said blend, while the balance of said blend comprises poly(vinylidene fluoride).
Claim 12
Dependent Claim
121 words
A process for forming biaxially oriented film in a continuous tubular film extrusion process from a blend of poly(vinylidene fluoride) and a second polymer miscible therewith comprising: continuously extruding said blend from an annular die to form a tubular extrudate; cooling said extrudate, and injecting air therein to form a first bubble while simultaneously drawing said bubble along its longitudinal axis; continuously collapsing said bubble with nip rolls; heating said collapsed bubble and injecting air therein to continuously form a second bubble while simultaneously drawing said second bubble, thereby continuously forming biaxially oriented film, wherein said second polymer comprises from about 15% to about 30%, on a weight basis, of said blend, while the balance of said blend comprises poly(vinylidene fluoride).
Claim 13
Dependent Claim
13 words
A process according to claim 10 wherein said second polymer is poly(methyl methacrylate).
References Cited (Backward Citations)
US2979777A
Cited
GB936398A
Cited
US3217073A
Cited
US3278663A
Cited
US3925339A
Cited
US3456044A
Cited
US3691264A
Cited
US3931446A
Cited
US3878274A
Cited
US3869534A
Cited
US4298719A
Cited
US4290983A
Cited
US4667001A
Cited
US4670527A
Cited
US4481158A
Cited
US4656234A
Cited
JPS6064827A
Cited
US4731288A
Cited
JPS62286720A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-01-20 | 1995-07-22 | 1996-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-20 | 1999-07-22 | 2000-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-20 | 2003-07-22 | 2004-01-21 | $7700.00 | Window Closed / Lapsed |