US 12,227,608 B2
Method for producing low-molecular weight polytetrafluoroethylene, and powder
Chisato Higashi, Osaka (JP); Eiji Masuda, Osaka (JP); Masayuki Tsuji, Osaka (JP); Akira Shimodo, Osaka (JP); Yasuhiro Nakano, Osaka (JP); and Akihiro Oshima, Suita (JP)
Assigned to DAIKIN INDUSTRIES, LTD., Osaka (JP); and OSAKA UNIVERSITY, Osaka (JP)
Filed by DAIKIN INDUSTRIES, LTD., Osaka (JP); and OSAKA UNIVERSITY, Suita (JP)
Filed on Jan. 7, 2022, as Appl. No. 17/571,031.
Application 17/571,031 is a continuation of application No. PCT/JP2020/027178, filed on Jul. 13, 2020.
Claims priority of application No. 2019-130586 (JP), filed on Jul. 12, 2019.
Prior Publication US 2022/0127391 A1, Apr. 28, 2022
Int. Cl. C08F 8/50 (2006.01); C08F 114/26 (2006.01); C08J 3/28 (2006.01)
CPC C08F 8/50 (2013.01) [C08F 114/26 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A powder comprising low-molecular-weight polytetrafluoroethylene,
the powder being substantially free from any of perfluorooctanoic acid and salts thereof,
the low-molecular-weight polytetrafluoroethylene having a melt viscosity at 380° C. of 1×102 to 7×105 Pa·s and satisfying a ratio P1/P2 of 3.30 or lower and a ratio P2/P0 of 0.260 to 0.450 in a primary differential spectrum obtainable by electron spin resonance measurement, wherein P1 represents a maximum intensity of a negative signal within a g value range of 2.014 to 2.016, P2 represents a maximum intensity of the negative signal within the g value range of 2.006 to 2.008, and P0 represents a maximum intensity of a positive signal,
wherein the powder is free from a powder obtained by irradiating high-molecular-weight polytetrafluoroethylene with radiation in the presence of 0.001% by mass or more of at least one selected from the group consisting of hydrocarbons, chlorinated hydrocarbons, alcohols, and carboxylic acids.