| abstract |
An ultra-high molecular weight ethylene-based copolymer powder comprising:n an ethylene unit and an α-olefin unit having 3 or more and 8 or less carbon atoms as structural units, wherein the ultra-high molecular weight ethylene-based copolymer powder has a viscosity-average molecular weight of 100,000 or more and 10,000,000 or less, a content of the α-olefin unit is 0.01 mol % or more and 0.10 mol % or less based on a total amount of the ethylene unit and the α-olefin unit, and in measurement with a differential scanning calorimeter under following conditions,an isothermal crystallization time is determined as a time from reaching 126° C. of Step A3 as a starting point (0 min) to giving an exothermic peak top due to crystallization and the isothermal crystallization time is 5 minutes or more. (Conditions for measurement of isothermal crystallization time) Step A1: holding at 50° C. for 1 minute and then an increase up to 180° C. at a temperature rise rate of 10° C./min, Step A2: holding at 180° C. for 30 minutes and then a decrease down to 126° C. at a temperature drop rate of 80° C./min, and Step A3: holding at 126° C. |