POLYOLEFIN RESIN POROUS FILM AND BATTERY SEPARATOR

• US 20130017430A1
• Filed: 03/15/2011
• Published: 01/17/2013
• Est. Priority Date: 03/18/2010
• Status: Abandoned Application

• Current Assignee: Mitsubishi Plastics Incorporated (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Plastics Incorporated (Mitsubishi Chemical Group Corp.)
• Inventors: Terakawa, Toru, Yamada, Takeyoshi, Usami, Yasushi
• Application Number:
  US13/635,758
• Publication Number:
  US 20130017430A1
• Time in Patent Office: Days
• US Class Current: 429/144
• CPC Class Codes: B32B 2307/734 Dimensional stability
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/449 having a layered structure
• CPC Class Codes: H01M 50/489 Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: H01M 50/491 Porosity
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 428/249981 Plural void-containing components
• CPC Class Codes: Y10T 428/263 Coating layer not in excess of 5 mils thick or equivalent
• CPC Class Codes: Y10T 428/264 Up to 3 mils

Abstract

As an object of the present invention, to provide a polyolefin resin porous film fulfilling high continuity, excellent dimensional stability and shutdown function which closes the pores sensitively and completely in a temperature range of 120 to 140° C. without closing the pores at less than 120° C. The present invention relates to a polyolefin resin porous film having at least one layer each of a layer comprising as the main component a polypropylene resin composition (A) and a layer comprising as the main component a polyethylene resin composition (B) fulfilling the condition (i) the melting point of the polyethylene resin composition (B) is 130° C. or higher, and the condition (ii) the melt flow rate (MFR) of the polyethylene resin composition (B) is 2.0 to 15 g/10 minutes.

Claims

1. A polyolefin resin porous film comprising:

a first layer comprising as a main component a polypropylene resin composition, and

a second layer comprising as a main component a polyethylene resin composition B,

wherein

a melting point of the polyethylene resin composition is 130°

C. or higher, and

a melt flow rate of the polyethylene resin composition is 2.0 to 15 g/10 minutes,

2. The polyolefin resin porous film of claim 1, having a β

-crystal activity.

3. The polyolefin resin porous film of claim 1, wherein a thermal shrink rate is less than 10% in a perpendicular direction with respect to a flow direction of the polyolefin resin porous film.

4. The polyolefin resin porous film of claim 1, having an air-permeability of 10 to 800 seconds/100 ml.

5. The polyolefin resin porous film of claim 1, having a shutdown function.

6. A battery comprising the polyolefin resin porous film of claim 1.

7. The polyolefin resin porous film of claim 1, wherein the melting point of the polyethylene resin composition B is 132°

C. or higher.

8. The polyolefin resin porous film of claim 1, wherein the melt flow rate of the polyethylene resin composition B is 2.2 to 10 g/10 minutes.

9. The polyolefin resin porous film of claim 1, wherein the melt flow rate of the polyethylene resin composition A is 0.1 to 15 g/10 minutes.

10. The polyolefin resin porous film of claim 1, wherein the melt flow rate of the polyethylene resin composition A is 0.5 to 10 g/10 minutes.

11. The polyolefin resin porous film of claim 1, wherein the polypropylene resin composition A has an isotactic pentad fraction of 80 to 99%.

12. The polyolefin resin porous film of claim 1, wherein the polypropylene resin composition A has an isotactic pentad fraction of 85 to 99%.

13. The polyolefin resin porous film of claim 1, wherein the polypropylene resin composition A has a ratio Mw/Mn of 1.5 to 10.0.

14. The polyolefin resin porous film of claim 1, wherein the polypropylene resin composition A has a ratio Mw/Mn of 2.0 to 6.0.

15. The polyolefin resin porous film of claim 1, having a thickness of 3 μ

m to 100 μ

m.

16. The polyolefin resin porous film of claim 1, having a thickness of 5 μ

m to 60 μ

m.

17. The polyolefin resin porous film of claim 1, having a porosity of 20% to 80%.

18. The polyolefin resin porous film of claim 1, having a porosity of 30% to 80%.

19. The polyolefin resin porous film of claim 1, having an air-permeability of 10 to 500 seconds/100 ml.

20. The polyolefin resin porous film of claim 1, wherein an air-permeability after heating at 135°

C. for 5 seconds is 50,000 seconds/100 ml or greater.