Polyethylene powder and molded article
A polyethylene powder, wherein, when a free induction decay curve obtained by the Carr-Purcell-Meiboom-Gill method in pulsed NMR is subjected to three-component approximation, the relaxation time T of each component and the abundance R of each component satisfy the following <requirement (1)> and <requirement (2)>: <Requirement (1)> An entanglement index at 180° C. determined by (formula I) is 12 to 25 ms: (entanglement index)= T α ×R α /( R α +R β )+ T β ×R β /( R α +R β ) (formula I) T α : relaxation time (ms) of low-mobility component α R α : abundance (%) of low-mobility component α T β : relaxation time (ms) of intermediate component β R β : abundance (%) of intermediate component β <Requirement (2)> An intermediate component ratio at 180° C. determined by (formula II) is 0.25 to 0.5: (intermediate component ratio)= R β /( R α +R β ) (formula II).
1 . A polyethylene powder, wherein, when a free induction decay curve obtained by the Carr-Purcell-Meiboom-Gill method in pulsed NMR is subjected to three-component approximation, a relaxation time T of each component and an abundance R of each component satisfy the following <requirement (1)> and <requirement (2)>:
<Requirement (1)>
an entanglement index at 180° C. determined by the following (formula I) is 12 ms or more and 25 ms or less:
(entanglement index)= T α ×R α /( R α +R β )+ T β ×R β /( R α +R β ) (formula 1)
T α : relaxation time (ms) of low-mobility component α
R α : abundance (%) of low-mobility component α
T β : relaxation time (ms) of intermediate component β
R β : abundance (%) of intermediate component β
<Requirement (2)>
an intermediate component ratio at 180° C. determined by the following (formula II) is 0.25 or more and 0.5 or less:
(intermediate component ratio)= R β /( R α +R β ) (formula II).
2 . The polyethylene powder according to claim 1 ,
wherein, regarding the abundance R of each component determined by subjecting a free induction decay curve obtained by the Carr-Purcell-Meiboom-Gill method in pulsed NMR to three-component approximation,
a rate of change in an abundance of the low-mobility component at 180° C. is −5% or more and 10% or less.
3 . The polyethylene powder according to claim 1 ,
wherein, regarding the abundance R of each component determined by subjecting a free induction decay curve obtained by the Carr-Purcell-Meiboom-Gill method in pulsed NMR to three-component approximation,
the rate of change in the abundance of the high-mobility component at 180° C. is 50% or less.
4 . The polyethylene powder according to claim 1 , which has an isothermal crystallization time at 125° C. of 5 minutes or less.
5 . The polyethylene powder according to claim 1 , which has a viscosity average molecular weight of 200,000 g/mol or more and 10,000,000 g/mol or less.
6 . The polyethylene powder according to claim 1 , which has a median diameter of 50 μm or more and 250 μm or less.
7 . The polyethylene powder according to claim 1 , which is for use in a battery separator.
8 . A molded article of the polyethylene powder according to claim 1 .
9 . The molded article according to claim 8 , which is a microporous membrane.
10 . The molded article according to claim 8 , which is a fiber.
11 . The molded article according to claim 8 , which is a battery separator.