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KR-102964263-B1 - Fluoropolymer composition and molded body

KR102964263B1KR 102964263 B1KR102964263 B1KR 102964263B1KR-102964263-B1

Abstract

The present disclosure provides a fluoropolymer composition having excellent tensile properties despite including a fluoropolymer that has been heated to a temperature above its melting point, and a molded article obtained from said fluoropolymer composition. The present disclosure provides a fluoropolymer composition that does not exhibit melt fluidity, comprising a fluoropolymer A that does not exhibit melt fluidity and has been heated to a temperature above its melting point, and a fluoropolymer B that exhibits melt fluidity.

Inventors

  • 무카에 히로후미
  • 기시카와 요스케
  • 야마나카 다쿠
  • 가토 다케토
  • 사카쿠라 아츠시
  • 이토 류오
  • 구보타 히로키
  • 나카우에 아야네

Assignees

  • 다이킨 고교 가부시키가이샤

Dates

Publication Date
20260513
Application Date
20220331
Priority Date
20210331

Claims (20)

  1. In a fluoropolymer composition that does not exhibit melt fluidity, It comprises fluoropolymer A that does not exhibit melt fluidity and has a history of being heated to a temperature above its melting point, fluoropolymer B that exhibits melt fluidity, and fluoropolymer C that does not exhibit melt fluidity and has a portion that has not a history of being heated to a temperature above its melting point, The above fluoropolymer A has one or more melting points in a temperature range below 333℃, and The above fluoropolymer C has one or more melting points in a temperature range of 333 to 360°C, and The melt flow rate (MFR) of the above fluoropolymer composition, the above fluoropolymer A, and the above fluoropolymer C is less than 0.25 g/10 min, and The MFR of the above fluoropolymer B is 0.25 g/10 min or higher, Fluoropolymer composition (except for cases where it is used in the manufacture of porous bodies).
  2. In claim 1, fluoropolymer A is a fluoropolymer composition in which polytetrafluoroethylene is used.
  3. The fluoropolymer composition according to claim 1 or 2, wherein fluoropolymer B is a fluoropolymer having a melting point of 320°C or lower.
  4. A fluoropolymer composition according to claim 3, having one or more melting points in a temperature range of less than 333℃ and one or more melting points in a temperature range of 333 to 360℃.
  5. In claim 1 or 2, the fluoropolymer composition comprises a tetrafluoroethylene unit and a modified monomer unit based on a modified monomer copolymerizable with tetrafluoroethylene, wherein the amount of the modified monomer unit is 1.0 mass% or less with respect to the total polymerization units, and The above modified monomer is at least one selected from the group consisting of perfluoroolefin, hydrogen-containing fluoroolefin, perhalolefin, perfluorovinyl ether, perfluoroallyl ether, (perfluoroalkyl)ethylene, and ethylene, Fluoropolymer composition.
  6. A fluoropolymer composition according to claim 1 or 2, wherein the average secondary particle size of the fluoropolymer composition is 5 to 700 μm.
  7. A fluorine resin composition according to claim 1 or 2, further comprising a low molecular weight fluorine-containing compound selected from a fluorine compound with a molecular weight of 800 or less or an anionic fluorine-containing surfactant having a molecular weight of 800 or less of an anionic portion, wherein the content of the low molecular weight fluorine-containing compound is 1 mass ppm or less with respect to the fluorine resin composition.
  8. A fluoropolymer composition in powder form according to claim 1 or 2.
  9. A fluoropolymer composition that is a compression molding powder according to claim 1 or 2.
  10. A fluoropolymer composition according to claim 1 or 2, having a tensile breaking strength of 10 MPa or more.
  11. A fluoropolymer composition according to claim 1 or 2, wherein the tensile fracture deformation is 150% or more.
  12. A fluoropolymer composition that does not exhibit melt fluidity, comprising fluoropolymer A that does not exhibit melt fluidity and has a history of being heated to a temperature above its melting point, and fluoropolymer B that exhibits melt fluidity.
  13. A fluoropolymer composition according to claim 12, wherein the content of fluoropolymer A in the fluoropolymer composition is 40 mass% or more.
  14. A fluoropolymer composition according to claim 12 or 13, wherein the content of fluoropolymer A in the fluoropolymer composition is 50 mass% or more.
  15. A fluoropolymer composition according to claim 12 or 13, wherein the D90 of the fluoropolymer A is 10 μm or more and 600 μm or less.
  16. A fluoropolymer composition according to claim 12 or 13, wherein the fluoropolymer A is ground by at least one grinder selected from the group consisting of an air jet mill, a hammer mill, a force mill, and a millstone grinder.
  17. In claim 12 or 13, the fluoropolymer composition comprises a tetrafluoroethylene unit and a modified monomer unit based on a modified monomer copolymerizable with tetrafluoroethylene, and A fluoropolymer composition comprising, with respect to the total polymerization units constituting the fluoropolymer composition, 99.0 mass% or more of the tetrafluoroethylene unit and 0.010 to 1.0 mass% of the modified monomer unit, wherein the modified monomer is at least one selected from the group consisting of perfluoroolefin, perhalolefin, perfluorovinyl ether, and perfluoroallyl ether.
  18. A fluoropolymer composition according to claim 12 or 13, wherein D90 is 10 μm or more and 600 μm or less.
  19. A fluoropolymer composition according to claim 12 or 13, wherein D10 is 4 μm or more and 9 μm or less.
  20. A fluoropolymer composition that is an assembly of the fluoropolymer composition according to claim 12 or 13.

Description

Fluoropolymer composition and molded body The present disclosure relates to a fluoropolymer composition and a molded article. Polytetrafluoroethylene (PTFE) that has been heated to a temperature above its melting point for molding processing does not yield sufficient physical properties even when used again as a molding material, so recycling for molding applications is limited to only a portion. Patent documents 1 and 2 describe technology regarding the recycling of PTFE that has been crushed after calcination or PTFE that has been heated. The present disclosure will be described in detail below. The present disclosure provides a fluoropolymer composition that does not exhibit melt fluidity, comprising a fluoropolymer A that does not exhibit melt fluidity and has a history of being heated to a temperature above its melting point, and a fluoropolymer B that exhibits melt fluidity. The fluoropolymer composition of the present disclosure includes fluoropolymer B, which exhibits melt fluidity, and thus has excellent tensile properties (e.g., tensile breaking strength, tensile breaking deformation) despite including fluoropolymer A, which has a history of being heated to a temperature above its melting point. This effect is thought to be due to the fact that, during molding, the interfaces between the particles of fluoropolymer A are filled by fluoropolymer B. In the fluoropolymer composition of the present disclosure, a method for distinguishing between fluoropolymer A and fluoropolymer B may be, for example, by placing the fluoropolymer composition on a hot stage, observing it under a microscope while increasing the temperature at 5°C/min, and determining whether the particles are fluoropolymer A or B based on whether the particle shape is maintained. The above fluoropolymer A has a history of being heated to a temperature above its melting point. Examples of such heating include heating for molding processing, heat treatment, etc. Fluoropolymer A preferably has a melting point of 100°C or higher and less than 333°C, more preferably less than 332°C, and even more preferably less than 331°C. The lower limit is not limited, but it is more preferable that it be 140℃, and even more preferable that it be 180℃ or higher. It is preferable that fluoropolymer A has one or more melting points in a temperature range below 333°C. The temperature range below 333°C is more preferably below 332°C, more preferably below 331°C, and also preferably above 100°C, more preferably above 140°C, and more preferably above 180°C. A melting point within the above range indicates that there is a history of heating to a temperature above the melting point. Fluoropolymer A may have a melting point in a temperature range of 333°C or higher. In this specification, the melting point of the fluoropolymer is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry [DSC] at a heating rate of 10°C/min using an X-DSC7000 (manufactured by Hitachi High-Tech Science Co., Ltd.). If there are two or more minimum points within a single melting peak, each is designated as the melting point. Fluoropolymer A does not exhibit melt fluidity. In this specification, "does not exhibit melt fluidity" means that the melt flow rate (MFR) is less than 0.25 g/10 min, preferably less than 0.10 g/10 min, more preferably 0.05 g/10 min or less. In this specification, MFR is a value obtained as the mass (g/10 min) of polymer flowing out per 10 minutes from a nozzle with an inner diameter of 2.095 mm and a length of 8 mm, using a melt indexer according to ASTM D1238 at a measurement temperature determined according to the type of fluoropolymer (e.g., 372°C for PFA or FEP, 297°C for ETFE) and a load (e.g., 5 kg for PFA, FEP, and ETFE). In the case of PTFE, it is a value obtained by measuring under the same measurement conditions as PFA. In addition, when a preform (micro-molded body) of a fluoropolymer is compression-molded and heated for at least one hour above the melting point of the fluoropolymer, if the reduction rate of the thickness after heating relative to the thickness before heating is less than 20%, or if the thickness after heating increases compared to the thickness before heating, it means that the fluoropolymer does not exhibit melt fluidity. As fluoropolymer A, polytetrafluoroethylene [PTFE] is preferred. The PTFE may be high molecular weight PTFE. The above PTFE as fluoropolymer A may be a homopolymer of TFE, or it may be a modified PTFE comprising 99.0 mass% or more of TFE-based polymerization units and 1.0 mass% or less of modified monomer-based polymerization units (hereinafter also referred to as "modified monomer units"). The above modified PTFE only needs to comprise TFE-based polymerization units and modified monomer units. The modified PTFE above preferably has a modified monomer unit content in the range of 0.00001 to 1.0 mass% with respect to the total polymerization