Method for manufacturing of cast films at high productivity

• US 5,075,065 A
• Filed: 11/28/1989
• Issued: 12/24/1991
• Est. Priority Date: 08/01/1988
• Status: Expired due to Term

• Current Assignee: Chemfab Corp. (Compagnie de Saint-Gobain SA)
• Original Assignee: Chemical Fabrics Corporation (Compagnie de Saint-Gobain SA)
• Inventors: Latorra, Michael N., Petriello, John V., Effenberger, John A., Koerber, Keith G.
• Primary Examiner(s): Lowe, James
• Application Number:
  US07/442,012
• Time in Patent Office: 756 Days
• Field of Search: 264/213, 264/127, 264/215
• US Class Current: 264/213
• CPC Class Codes: B29C 41/12 Spreading-out the material on a substrate , e.g. on the surface of a liquid
• CPC Class Codes: B29C 41/28 by depositing flowable material on an endless belt
• CPC Class Codes: B29C 41/46 Heating or cooling
• CPC Class Codes: B29K 2027/12 containing fluorine
• CPC Class Codes: B29L 2007/008 Wide strips, e.g. films, webs

Abstract

A method is provided for preparation of a fluoro-polymeric film on a carrier, covering:

(a) preparing an aqueous dispersion of polymeric material;

(b) dipping a fluoropolymer pre-treated carrier belt through the dispersion so that a coating of the dispersion is formed on the carrier belt;

(c) passing the coated carrier belt through a metering zone to remove excess dispersion;

(d) drying the metered coated carrier to remove the water from the dispersion; and

(e) heating the dried coated carrier to a temperature sufficient to consolidate the dispersion. The carrier belt is formed from a material of low thermal mass having chemical and dimensional stability at the consolidation temperature of the dispersion and a work of adhesion between the carrier belt and the dispersion that does not exceed the yield strength of the consolidated fluoropolymeric film.

Claims

1. An improved method for high productivity preparation of a polymeric film on a carrier, comprising:

(a) preparing an aqueous dispersion comprising a film forming polymeric material;

(b) pre-treating the carrier with a suitable fluoropolymer to reduce the surface energy of the carrier surface;

(c) dipping the pre-treated carrier through the dispersion such that a coating of the dispersion is formed on the carrier;

(d) passing the coated carrier through a metering device to remove excess dispersion;

(e) drying the metered coated, pre-treated carrier to remove the water from the dispersion; and

(f) heating the dried coated, pre-treated carrier to a temperature sufficient to consolidate the dispersion, wherein the carrier is formed from a material of low thermal mass having chemical and dimensional stability at the consolidation temperature of the dispersion and a work of adhesion that does not exceed the yield strength of the consolidated polymeric film.

2. A method according to claim 1, wherein the carrier is dipped in the dispersion at a rate of at least 10 linear feet per minute.

3. A method according to claim 1, wherein the carrier is selected from among films of high melting thermoplastics, films of thermosetting plastics, coated or laminated textiles formed from a thermally stable plastic or resin and a thermally stable reinforcement, a plastic coated metal foil and metallized or metal foil laminated thermally stable plastic or resins.

4. A method according to claim 1, wherein the film is a fluoropolymer film.

5. A method according to claim 4, wherein the fluoropolymer is selected from the group consisting of fluorine-containing homopolymers, copolymers and terpolymers of tetrahaloethylenes, vinyl fluoride, vinylidene fluoride, hexafluoropropylene, perfluoroalkyl vinyl ethers, ethylene and propylene.

6. A method according to claim 1 wherein the carrier is pre-treated with PTFE.