Separator for non-aqueous batteries and non-aqueous battery equipped with same, and process for manufacturing separator for non-aqueous batteries
Provided is a separator for non-aqueous batteries, capable of being usefully used in non-aqueous batteries, and a non-aqueous battery equipped with this separator. The separator for non-aqueous batteries includes: a base layer comprising a fiber aggregate, and an electrolyte-swellable resin layer formed on at least one surface of the base layer, the resin layer comprising a urethane resin (C) obtained by reacting a polyol (A) including a vinyl polymer (a1) and a polyether polyol (a2) with a polyisocyanate (B). The vinyl polymer (a1) has as a main chain a vinyl polymer (a1′) having two hydroxyl groups at one of the termini of the main chain, and a polyoxyethylene chain having a number average molecular weight of 200 to 800 as a side chain, the percentage of the polyoxyethylene chain based on the vinyl polymer (a1) being within the range of 70 mass % to 98 mass %.
1. A separator for non-aqueous batteries, the separator comprising:
a base layer comprising a fiber aggregate; and
an electrolyte-swellable resin layer formed on at least one surface of the base layer, such that the electrolyte-swellable resin layer and the base layer are integrated with each other,
wherein:
the electrolyte-swellable resin layer is capable of swelling in the presence of a liquid electrolyte and comprises a urethane resin (C);
the urethane resin (C) is obtained by reacting a polyol (A) with a polyisocyanate (B);
the polyol (A) comprises a vinyl polymer (a1) having a number average molecular weight of 2000 to 7000 and a polyether polyol (a2);
the vinyl polymer (a1) comprising as a main chain a vinyl polymer (a1′) comprising two hydroxyl groups at one of the termini of the main chain, and a polyoxyethylene chain having a number average molecular weight of 200 to 800 as a side chain of the vinyl polymer (a1′); and
a percentage of the polyoxyethylene chain based on the vinyl polymer (a1) is within a range of 70 mass % to 98 mass %.
2. The separator of claim 1 , wherein the vinyl polymer (a1) is obtained by reacting a chain transfer agent (D), comprising two hydroxyl groups and one mercapto group, with a vinyl monomer (E) comprising a vinyl monomer (e) comprising a polyoxyethylene chain having a number average molecular weight of 200 to 800.
3. The separator of claim 1 , wherein the electrolyte-swellable resin layer is substantially non-porous.
4. The separator of claim 1 , wherein the base layer comprises a layer of a heat-resistant polymer formed from a heat infusible polymer or a high melting-point polymer having a melting point exceeding 200° C.
5. The separator of claim 4 , wherein the heat-resistant polymer comprises at least one member selected from the group consisting of a fully aromatic polyamide polymer, a polyvinyl alcohol polymer, and a cellulose polymer.
6. The separator of claim 1 , wherein the base layer comprises a nonwoven fabric.
7. The separator of claim 6 , wherein the nonwoven fabric is at least one selected from the group consisting of a wet nonwoven fabric, a dry nonwoven fabric, a meltblown nonwoven fabric, a spun bond nonwoven fabric, an electrospun nonwoven fabric, and a nonwoven fabric laminate thereof.
8. The separator of claim 1 , wherein the base layer comprises a laminate of a heat-resistant polymer layer and a low melting-point polymer layer of a low melting-point polymer having a melting point of 100 to 200° C.
9. The separator of claim 8 , wherein the low melting-point polymer layer is a nonwoven fabric comprising a nanofiber having an average fiber diameter of not greater than 1000 nm.
10. The separator of claim 8 , wherein the low melting-point polymer comprises at least one selected from the group consisting of a polyolefin polymer, an ethylene-vinyl alcohol copolymer, and a fluoropolymer.
11. A process for manufacturing a separator for non-aqueous batteries, the process comprising attaching a sheet or film to at least one surface of a base material comprising a fiber aggregate,
wherein:
the sheet or film is formed from a urethane resin (C) obtained by reacting a polyol (A) with a polyisocyanate (B);
the polyol (A) comprises a vinyl polymer (a1) having a number average molecular weight of 2000 to 7000 and a polyether polyol (a2);
the vinyl polymer (a1) comprises as a main chain a vinyl polymer (a1′), comprising two hydroxyl groups at one of the termini of the main chain, and a polyoxyethylene chain having a number average molecular weight of 200 to 800 as a side chain of the vinyl polymer (a1′); and
a percentage of the polyoxyethylene chain based on the vinyl polymer (a1) is within a e range of 70 mass % to 98 mass.
12. A non-aqueous battery comprising the separator of claim 1 .
13. The separator of claim 2 , wherein the electrolyte-swellable resin layer is substantially non-porous.
14. The separator of claim 9 , wherein the low melting-point polymer comprises at least one selected from the group consisting of a polyolefin polymer, an ethylene-vinyl alcohol copolymer, and a fluoropolymer.