Extrusion of films of vinylidene fluoride polymers
Patent 4481158 Issued on November 6, 1984. Estimated Expiration Date: 
November 16, 2002. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 16, 2002. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2728951 3087198 3402428 3676539 3691264 3878274 Extrusion method and apparatus Production of piezoelectric PVDF films Method of producing pyro-electric and piezo-electric elements Process for manufacturing a piezoelectric transducer made from a polymer material InventorsApplicationNo. 06/442122 filed on 11/16/1982US Classes:264/435, Molecular aligning or molecular orientating (e.g., poling, etc.)264/127, Fluorocarbon resin264/178R, Into a liquid bath264/210.1, And reshaping264/210.2, Including a step other than application or removal of tension264/289.6With shrinking or with liquid contact during or after stretchingExaminersPrimary: Lowe, JamesAttorney, Agent or FirmInternational ClassesB29C 47/00 (20060101)H01L 41/22 (20060101) H01L 41/26 (20060101) B29D 7/00 (20060101) C08J 5/18 (20060101) Foreign Application Priority Data1981-11-16 FRAbstractThe film (11) extruded from a vinylidene fluoride polymer is subjected to a stretching of at least 200% while still in the molten state, and then cooled rapidly to a temperature below 50° C.The equipment comprises, in series, an extruding device (1) (2), a cooling device consisting of a thermostatically controlled liquid bath (6), the level of which is located at a distance of 10 to 300 mm from the extruding device, and a device (8) (9) for stretching the extruded film by at least 200% in its part located between the extruding device and the cooling device.The film obtained is suitable for manufacturing piezoelectric films.Other References
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