Abstract: To provide a working fluid for heat cycle which has a small temperature glide, a sufficiently low discharge temperature, high durability and less influence over global warming, and with which a heat cycle system excellent in the system maintenance properties and the cycle performance (capacity) is achieved, a composition for a heat cycle system, and a heat cycle system. A working fluid for heat cycle, which contains trifluoroethylene and difluoromethane, wherein the proportion of the total amount of trifluoroethylene and difluoromethane based on the entire amount of the working fluid for heat cycle is higher than 90 mass % and at most 100 mass %, and the mass ratio represented by trifluoroethylene/difluoromethane in the working fluid for heat cycle is from 41/59 to 59/41, a composition for a heat cycle system, and a heat cycle system employing the composition.

Abstract: To provide a working fluid for heat cycle which has a small temperature glide, a sufficiently low discharge temperature, high durability and less influence over global warming, and with which a heat cycle system excellent in the system maintenance properties and the cycle performance (capacity) is achieved, a composition for a heat cycle system, and a heat cycle system. A working fluid for heat cycle, which contains trifluoroethylene and difluoromethane, wherein the proportion of the total amount of trifluoroethylene and difluoromethane based on the entire amount of the working fluid for heat cycle is higher than 90 mass % and at most 100 mass %, and the mass ratio represented by trifluoroethylene/difluoromethane in the working fluid for heat cycle is from 41/59 to 59/41, a composition for a heat cycle system, and a heat cycle system employing the composition.

Abstract: To provide a method for purifying R-1234yf, whereby it is possible to efficiently remove even impurities such as R-1243zf, etc. which are difficult to separate by distillation purification, from a mixture containing R-1234yf as the main component and various impurities, such as a gas formed by reacting R-1214ya with hydrogen. The method for purifying R-1234yf comprises a step of bringing a mixture which contains R-1234yf as the main component and also contains hydrohaloalkene impurities other than R-1234yf and hydrohaloalkane impurities, into contact with a solvent that has an extraction/removal index (r), as represented by the formula r=[4×(?D?17.2)2+(?P?8.3)2+(?H?2.6)2]1/2, of at most 6.5, so as to remove at least a part of the hydrohaloalkene impurities and hydrohaloalkane impurities.

Abstract: To provide a method for purifying R-1234yf, whereby it is possible to efficiently remove even impurities such as R-1243zf, etc. which are difficult to separate by distillation purification, from a mixture containing R-1234yf as the main component and various impurities, such as a gas formed by reacting R-1214ya with hydrogen. The method for purifying R-1234yf comprises a step of bringing a mixture which contains R-1234yf as the main component and also contains hydrohaloalkene impurities other than R-1234yf and hydrohaloalkane impurities, into contact with a solvent that has an extraction/removal index (r), as represented by the formula r=[4×(?D?17.2)2+(?P?8.3)2+(?H?2.6)2]1/2, of at most 6.5, so as to remove at least a part of the hydrohaloalkene impurities and hydrohaloalkane impurities.

Abstract: The present invention provides a continuous resin recovery method for recovering resin from which foreign matters and volatile components are sufficiently removed and which is highly purified and suitable for optical use. The continuous resin recovery method comprises heating a resin solution in a heating pipe at a temperature at least the boiling point of the solvent, introducing the resin solution heated at a temperature at least the boiling point of the solvent into a rough drying chamber maintained at a reduced pressure, separating the resin from the solvent vapor in the rough drying chamber, melting the separated resin, introducing the molten resin in a precise drying chamber kept at a reduced pressure, and passing the molten resin through a perforated plate in the precise drying chamber.

Abstract: The present invention provides a continuous resin recovery method for recovering resin from which foreign matters and volatile components are sufficiently removed and which is highly purified and suitable for optical use. The continuous resin recovery method comprises a step of heating a resin solution in a heating pipe at a temperature at least the boiling point of the solvent, a step of introducing the resin solution heated at a temperature at least the boiling point of the solvent into a rough drying chamber maintained at a reduced pressure, a step of separating the resin from the solvent vapor in the rough drying chamber, a step of melting the separated resin, a step of introducing the molten resin in a precise drying chamber kept at a reduced pressure, and a step of passing the molten resin through a perforated plate in the precise drying chamber.