TETRAFLUOROETHYLENE POLYMER AND AQUEOUS DISPERSION THEREOF

• US 20090281231A1
• Filed: 04/13/2007
• Published: 11/12/2009
• Est. Priority Date: 04/13/2006
• Status: Active Grant

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Ono, Makoto, Kasai, Shunji, Sawada, Yasuhiko, Yamanaka, Taku
• Granted Patent: US 7,820,775 B2
• Time in Patent Office: Days
• US Class Current: 524/546
• CPC Class Codes: C08F 114/26 Tetrafluoroethene
• CPC Class Codes: C08F 14/26 Tetrafluoroethene
• CPC Class Codes: C08F 2/22 Emulsion polymerisation
• CPC Class Codes: C08F 214/26 Tetrafluoroethene
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated

Abstract

The invention provides a TFE polymer capable of providing stretched materials excellent in membrane homogeneity. The present invention is related to a tetrafluoroethylene polymer having stretchability and non-melt-processability and having a standard specific gravity of 2.140 to 2.165, wherein, with regard to the heat-of-fusion curve obtained by subjecting the tetrafluoroethylene polymer in the form of an unbaked polymer to be measured having no history of being heated to a temperature of 300° C. or higher to differential scanning calorimetry at a programming rate of 2° C./minute, the ratio between the amount of heat, S₂ mJ/mg, absorbed within the temperature range of from the temperature T₀° C., which is lower by 2.5° C. than the temperature T_p° C. corresponding to the minimum point on the curve (provided that 340≦T_p≦345), up to 350° C., and the amount of heat, S₁ mJ/mg, absorbed within the temperature range of from 320° C. up to the above-mentioned T₀° C., namely the ratio [S₂/S₁], is not lower than 0.90.

Claims

1. A tetrafluoroethylene polymer having stretchability and non-melt-processability and having a standard specific gravity of 2.140 to 2.165,

wherein, with regard to the heat-of-fusion curve obtained by subjecting the tetrafluoroethylene polymer in the form of an unbaked polymer to be measured having no history of being heated to a temperature of 300°

C. or higher to differential scanning calorimetry at a programming rate of 2°

C./minute,

the ratio between the amount of heat, S₂ mJ/mg, absorbed within the temperature range of from the temperature T₀°

C., which is lower by 2.5°

C. than the temperature T_p°

C. corresponding to the minimum point on the curve (provided that 340≦

T_p≦

345), up to 350°

C., and the amount of heat, S₁ mJ/mg, absorbed within the temperature range of from 320°

C. up to the above-mentioned T₀°

C., namely the ratio [S₂/S₁], is not lower than 0.90.

2. The tetrafluoroethylene polymer according to claim 1,

wherein the ratio [S₂/S₁] is not lower than 0.95.

3. The tetrafluoroethylene polymer according to claim 1,

wherein the ratio [S₂/S₁] is not lower than 1.00.

4. The tetrafluoroethylene polymer according to claim 1,

wherein the tetrafluoroethylene polymer constitutes a fine powder obtained by emulsion polymerization.

5. An aqueous tetrafluoroethylene polymer dispersion comprising a tetrafluoroethylene polymer dispersed in an aqueous medium,

said tetrafluoroethylene polymer being the tetrafluoroethylene polymer according to claim 1.

6. A stretched material obtained by using a tetrafluoroethylene polymer,

said tetrafluoroethylene polymer being the tetrafluoroethylene polymer according to claim 1.

7. An article comprising a stretched material,

said stretched material being the stretched material according to claim 6.