Abstract: A method for producing a fluoropolymer which method includes polymerizing a perfluoromonomer in an aqueous medium in the presence of a polymer (1) to obtain a fluoropolymer, wherein the content of a polymerized unit derived from the perfluoromonomer in the fluoropolymer is 90 mol % or more based on all polymerized units of the fluoropolymer, the polymer (1) is a polymer of a monomer (1) represented by the general formula (1): CF2?CF—O—R-(Rf-SO3M)m, a polymerized unit (1) derived from the monomer (1) in the polymer (1) is 50% by mass or more based on all polymerized units of the polymer (1), and the content of a dimer and a trimer of the monomer (1) in the polymer (1) is 1.0% by mass or less based on the polymer (1).

Abstract: The present disclosure provides a method for producing a perfluoroelastomer aqueous dispersion by polymerizing a perfluoromonomer in the presence of a polymer (1) and an aqueous medium to produce an aqueous dispersion of a perfluoroelastomer, the polymer (1) containing a polymerization unit (1) based on a monomer (1) represented by a general formula (1) and the polymer (1) having an ion exchange capacity of 1.50 meq/g or more.

Abstract: An object of the present disclosure is to provide a composition in which a disproportionation reaction of a refrigerant is suppressed, and in which the refrigerant has excellent stability. Another object of the present disclosure is to provide a composition comprising a refrigerant useful for air-conditioning systems. The composition comprises a refrigerant, wherein the refrigerant comprises a refrigerant that undergoes disproportionation and a refrigerant that does not undergo disproportionation.

Abstract: The propagation of a disproportionation reaction of a refrigerant is suppressed. Disclosed is a method of using a composition as a refrigerant in a compressor, in which the composition includes one or more compounds selected from the group of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene, and 1,3,3,3-tetrafluoropropene, and the dimension of a gap of a predetermined portion through which the refrigerant flows around an ignition energy generation portion in the compressor is less than or equal to 2 mm.

Abstract: The propagation of a disproportionation reaction of a refrigerant is suppressed. Disclosed is a method that uses a composition as a refrigerant in a compressor, in which the composition includes one or more compounds selected from the group of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene, and 1,3,3,3-tetrafluoropropene, and the flow rate of the refrigerant flowing through a region around an ignition energy generation portion in the compressor under a predetermined high-pressure condition is greater than or equal to 1 m/s.

Abstract: The propagation of a disproportionation reaction of a refrigerant is suppressed. Disclosed is a method that uses a composition as a refrigerant in a compressor, in which the composition includes one or more compounds selected from the group of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene, and 1,3,3,3-tetrafluoropropene, and the flow rate of the refrigerant flowing through a discharge pipe of the compressor under a predetermined high-pressure condition is greater than or equal to 1 m/s.