# US 5,703,202 A · Process for treating liquid crystal polymer film > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,202 A - Document ID: US5703202A - Status: Granted - Kind: A - Application number: 08/627,493 - Filed: 1996-04-02 - Granted: 1997-12-30 - Earliest claimed: 1994-09-16 - Assignees: Hoechst Celanese Corporation; Kuraray Co., Ltd. - Inventors: Randy Douglas Jester; John Arthur Penoyer; Douglas Duane Roth; Detlef Frank; Minoru Onodera; Takeichi Tsudaka; Toshiaki Sato; Tohei Moritani - Web page: https://patentgrep.com/patent/US5703202A ## CPC - B29C 71/02: Thermal after-treatment {(B29C71/0063 and B29C71/0072 take precedence)} - B29C 48/00: Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor (extrusion blow-moulding B29C49/04) - B29C 48/0018: {combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence)} - B29C 48/07: Flat, e.g. panels - B29C 48/08: flexible, e.g. films - B29C 48/21: the layers being joined at their surfaces - B29K 2105/0079: {Liquid crystals} - B29L 2007/008: {Wide strips, e.g. films, webs} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract A process for treating a liquid crystal polymer film which includes the steps of: heating a film obtained by extrusion molding of a liquid crystal polymer, while contacting at least one surface of the film with a supporting body, to melt the polymer; cooling the melted polymer to form a solidified polymer layer; and separating the solidified polymer layer from the supporting body. The process readily provides liquid crystal polymer films having excellent resistance to intra-layer delamination and high tensile strength and elongation, as well as excellent resistance to abrasion, dimensional stability when heated, and resistance to folding. ## Claims ### Claim 1 A heat-treated polymer film made by the process comprising the steps of: (a) heating a film made by the extrusion molding of a polymer capable of forming an optically anisotropic melt phase while contacting at least one surface of said film with a supporting body, to a temperature sufficient to melt said polymer; (b) cooling the melted polymer to form a solidified polymer layer; and (c) separating said solidified polymer layer from said supporting body; said heat-treated polymer film having an intra-layer peeling strength measured by conducting a 90.degree. peeling test in accordance with JIS C6471 of at least 2 kg/cm; a tensile strength measured in accordance with JIS C2318 of at least 5 kg/mm.sup.2 ; a thermal expansion coefficient that is positive when measured along four different lines in the film plane, wherein each of said four lines passes through a common point on the film plane, with the second line being at an angle of 45.degree. with respect to the first line, with the third line being at an angle of 45.degree. with respect to the second line, and with the fourth line being at an angle of 45.degree. with respect to the third line; and a dimensional change ratio when heated of not more than 0.1% in its absolute value, wherein said ratio is ›(L.sub.1 -L.sub.0)/L.sub.0 !.times.100%, where L.sub.0 is the length of a film sample measured at 25.degree. C. and L.sub.1 is the length of the same film sample measured at 25.degree. C. after being heated in air at 190.degree. C. for 30 minutes under no tension; and a degree of planar orientation of 50 to 70% as measured by x-ray diffractometry. ### Claim 2 (depends on 1) The heat-treated polymer film as recited in claim 1, wherein said supporting body comprises a metal foil, and wherein said separating step (c) is accomplished by dissolving said metal foil off of said polymer layer. ### Claim 3 (depends on 1) The heat-treated polymer film as recited in claim 1, wherein said solidified polymer layer is separated from said supporting body by peeling. ### Claim 4 (depends on 1) The heat-treated polymer film as recited in claim 1, wherein said process further comprises the step of: heating said solidified polymer layer, either before or after separation thereof from said supporting body, at a temperature in the range of from a minimum of about 150.degree. C. to a maximum of about 30.degree. C. below the thermal deformation temperature that said film had before undergoing said heating step. ### Claim 5 (depends on 1) The heat-treated polymer film as recited in claim 1, said film having a resistance to folding, as measured in accordance with JIS P8115 with an MIT tester, of at least 3000 strokes. ### Claim 6 (depends on 1) The heat-treated polymer film as recited in claim 1, said film having a tensile elongation at break as measured by JIS C2318 of at least 10%. ### Claim 7 (depends on 1) The heat-treated polymer film as recited in claim 1, said film having a degree of thickness orientation of 50 to 80% as measured by x-ray diffractometry. ### Claim 8 (depends on 1) The heat-treated polymer film as recited in claim 1, said film having a ratio between the maximum value and minimum value of penetrated microwave intensity, when irradiated with a microwave in a direction perpendicular to the film surface by the microwave transmission method, of not more than 2. ### Claim 9 (depends on 1) The heat-treated polymer film as recited in claim 1, wherein said polymer comprises monomer units derived from 6-hydroxy-2-naphthoic acid and 4-hydroxybenzoic acid. ### Claim 10 (depends on 1) The heat-treated polymer film as recited in claim 1, wherein said heating step (a) is carried out under pressure.