Laminated porous film, separator for non-aqueous electrolyte secondary cell, non-aqueous electrolyte secondary cell, and production method for laminated porous film

2:

• The laminated porous film according to claim 1, wherein a ratio Td/TPO of an absolute value (Td) of a difference in average thickness between the porous coating layers on the front and back surfaces of the polyolefin resin porous film to a thickness (TPO) of the polyolefin resin porous film is 0.1 or more and 0.5 or less.

3:

• The laminated porous film according to claim 1, wherein the porous layer A contains a polypropylene resin as a major component.

4:

• The laminated porous film according to claim 1, wherein the porous layer B contains a polyethylene resin as a major component.

5:

• The laminated porous film according to claim 1, wherein the polyolefin resin porous film has a porosity of 30% or more and 50% or less.

6:

• The laminated porous film according to claim 1, wherein the binder resin composition has an equilibrium water content of 1% or more.

7:

• The laminated porous film according to claim 1, which has a melt in-plane shrinkage of 8% or less.

8:

• A separator for a non-aqueous electrolyte secondary cell, comprising the laminated porous film according to claim 1.

9:

• A non-aqueous electrolyte secondary cell comprising the separator for a non-aqueous electrolyte secondary cell according to claim 8.

10:

• A method for producing a laminated porous film, comprising:
• applying a tension in a width direction to a polyolefin resin porous film which has a structure where porous layers A each containing a polyolefin resin having a melting point of 150° C. or more as a major component and a porous layer B containing a polyolefin resin as a major component and undergoing pore closure in a temperature range of 100° C. or more and less than 150° C. are in a structure of A/B/A and has a width shrinkage of less than 0.1% in a heat treatment at a temperature of 130° C. for 1 hour, so as to have a width shrinkage of 0.1% or more and 3% or less in a heat treatment at a temperature of 130° C. for 1 hour;
• and then forming a porous coating layer containing inorganic particles and a binder resin composition on at least one surface of the polyolefin resin porous film.