Polyethylene powder, microporous membrane, and fiber
It is intended to provide a polyethylene powder which can offer a fiber excellent in resistance to end breakage, dimensional stability, and acid resistance and/or a microporous membrane excellent in dimensional stability and acid resistance, and a microporous membrane and a fiber which are obtained by forming the polyethylene powder. The present invention provides a polyethylene powder comprising: 0.5 ppm or higher and 3,000 ppm or lower of aluminum hydroxide having an average particle size smaller than 50 μm; and 0.5 ppm or higher and 12 ppm or lower of a magnesium element, wherein the polyethylene has a viscosity-average molecular weight of 100,000 or larger.
1. A polyethylene powder comprising:
0.5 ppm or higher and 3,000 ppm or lower of an aluminum hydroxide having an average particle size smaller than 50 μm; and
0.5 ppm or higher and 12 ppm or lower of a magnesium element, wherein a viscosity-average molecular weight of the polyethylene powder is 100,000 or larger,
the polyethlene powder is obtained using a metallocene catalyst.
2. The polyethylene powder according to claim 1 , wherein a content of the aluminum hydroxide having a minor axis of 50 μm or larger is 10 particles or less in 500 g of the polyethylene powder.
3. A microporous membrane which is obtained by forming the polyethylene powder according to claim 1 .
4. A fiber which is obtained by forming the polyethylene powder according to claim 1 .
5. A method for producing a polyethylene powder according to claim 1 , comprising the steps of:
polymerizing ethylene in the presence of a metallocene catalyst for olefin polymerization to obtain a polyethylene powder;
deactivating the catalyst for olefin polymerization; and
drying the polyethylene powder, wherein
the step of deactivating the catalyst for olefin polymerization comprises spraying a catalyst deactivator onto the polyethylene powder.
6. The method for producing the polyethylene powder according to claim 5 , wherein the catalyst deactivator is water, wherein the water is sprayed in a form of steam.
7. The method for producing the polyethylene powder according to claim 5 , wherein the catalyst deactivator is water, wherein the water is sprayed in a form of steam as a mixed gas with an inert gas.
8. The polyethylene powder according to claim 1 , wherein the polyethylene powder has 100 ppm or higher and 1,000 ppm or lower of the aluminum hydroxide.
9. The polyethylene powder according to claim 1 , wherein the average particle size of the aluminum hydroxide is larger than 0.02 μm.
10. The polyethylene powder according to claim 1 , wherein the average particle size of the aluminum hydroxide is smaller than 10 μm and larger than 0.5 μm.
11. The polyethylene powder according to claim 1 , wherein the polyethylene powder has 5 ppm or higher and 6 ppm or lower of the magnesium element.
12. The polyethylene powder according to claim 1 , wherein the polyethylene powder comprises ethylene homopolymers or copolymers of ethylene and olefin, wherein the olefin is at least one olefin selected from the group consisting of α-olefins having 3 to 20 carbon atoms, cyclic olefins having 3 to 20 carbon atoms, compounds represented by the formula CH 2 ═CHR 1 , wherein R 1 is an aryl group having 6 to 20 carbon atoms, and linear, branched, or cyclic dienes having 4 to 20 carbon atoms.
13. The polyethylene powder according to claim 12 , wherein the polyethylene powder comprises copolymers of ethylene and olefin, wherein the olefin is propylene or 1-butene.
14. The polyethylene powder according to claim 1 , wherein the viscosity-average molecular weight of the polyethylene powder is 10,000,000 or smaller.
15. A lithium ion secondary battery separator comprising the polyethylene powder according to claim 1 , wherein the viscosity-average molecular weight of the polyethylene powder is 100,000 or larger and 2,000,000 or smaller.
16. A lithium ion secondary battery separator comprising the polyethylene powder according to claim 1 , wherein the viscosity-average molecular weight of the polyethylene powder is 200,000 or larger and 1,200,000 or smaller.
17. A lead storage battery separator comprising the polyethylene powder according to claim 1 , wherein the viscosity-average molecular weight of the polyethylene powder is 4,000,000 or larger and 10,000,000 or smaller.
18. A lead storage battery separator comprising the polyethylene powder according to claim 1 , wherein the viscosity-average molecular weight of the polyethylene powder is 6,000,000 or larger and 8,000,000 or smaller.
19. The fiber according to claim 4 , wherein the viscosity-average molecular weight of the polyethylene powder is 1,500,000 or larger and 10,000,000 or smaller.
20. The fiber according to claim 4 , wherein the viscosity-average molecular weight of the polyethylene powder is 4,000,000 or larger and 8,000,000 or smaller.