THERMOPLASTIC FILM, METHODS FOR MAKING SUCH FILM, AND THE USE OF SUCH FILM AS BATTERY SEPARATOR FILM
A thermoplastic film including a microporous polymeric membrane; and a non-woven web bonded to the polymeric microporous membrane, wherein the web comprises a plurality of fibers comprising polyolefin having a Tm≧85.0° C. and a Te-Tm≦10.0° C.
1 . A thermoplastic film comprising:
a microporous polymeric membrane; and
a non-woven web bonded to the polymeric microporous membrane, wherein the web comprises a plurality of fibers comprising polyolefin having a Tm≧85.0° C. and a Te-Tm≦10.0° C.
2 . The thermoplastic film of claim 1 , wherein the polyolefin comprises polyethylene having an Mw of 1.5×10 4 to 5.0×10 4 and an MWD of 1.5 to 5.0.
3 . The thermoplastic film of claim 1 , wherein the polyolefin comprises polyethylene homopolymer.
4 . The thermoplastic film of claim 1 , wherein the polyolefin comprises polyethylene copolymer.
5 . The thermoplastic film of claim 2 , wherein the polyethylene has a melt index of ≦1.0×10 2 .
6 . The thermoplastic film of claim 1 , wherein the polyolefin has a Tm of 95.0° C. to 130.0° C., and a Te-Tm of 1.0° C. to 5.0° C.
7 . The thermoplastic film of claim 4 , wherein the polyethylene copolymer comprises ≦10.0 mol. % of hexene-1 or octene-1 comonomer, and wherein the polyethylene copolymer has a CDBI≧50.0%, an Mw of 1.5×10 4 to 5.0×10 4 , an MWD of 1.8 to 3.5, a Tm of 100.0° C. to 126.0° C., and a Te-Tm of 2.0° C. to 4.0° C.
8 . The thermoplastic film of claim 1 , wherein the microporous polymeric membrane comprises polyethylene and/or polypropylene.
9 . The thermoplastic film of claim 1 , wherein the microporous polymeric membrane comprises polyethylene having an Mw≦1.0×10 6 .
10 . The thermoplastic film of claim 1 , wherein the polymeric microporous membrane is multi-layered and at least one layer comprises polypropylene.
11 . The thermoplastic film of claim 10 , wherein the polypropylene has an Mw≧1.0×10 6 and a heat of fusion≦1.0×10 2 J/g.
12 . The thermoplastic film of claim 1 , wherein the thermoplastic film has a shutdown temperature≦138° C.
13 . The thermoplastic film of claim 1 , the thermoplastic film having a meltdown temperature≧145.0° C.
14 . The thermoplastic film of claim 1 , the thermoplastic film having a normalized air permeability≦1.0×10 3 sec/100 cm 3 /20 μm, a porosity≧25%, and a normalized pin puncture strength≧3.0×10 3 mN/20 μm.
15 . A battery separator film comprising the thermoplastic film of claim 1 .
16 . A method for producing a thermoplastic film comprising combining a non-woven web and a microporous polymeric membrane, the web comprising a plurality of fibers comprising polyolefin having a Tm≧85.0° C. and a Te-Tm≦10.0° C.
17 . The method of claim 16 , wherein the polyolefin comprises a copolymer of ethylene and ≦10.0 mol. % of an octane-1 or hexane-1 comonomer, and wherein the copolymer has a CDBI≧50.0% by weight, an Mw of 1.5×10 4 to 5.0×10 4 , an MWD of 1.8 to 3.5, a Tm of 100.0° C. to 126.0° C., and a Te-Tm of 2.0° C. to 4.0° C.
18 . The method of claim 16 , wherein the microporous polymeric membrane comprises polypropylene having an Mw≧1.0×10 6 and a heat of fusion≧1.0×10 2 .
19 . The method of claim 16 , wherein the web is produced by meltblowing the polyolefin at a primary hot air flow rate of 9.5 liters/sec to 11.3 liters/sec per 2.54 cm of die width, a primary hot air pressure of 115 kPa to 205 kPa, a primary hot air temperature of 200° C. to 350° C., and at a polyolefin throughput rate of 0.01 ghm to 1.25 ghm.
20 . The thermoplastic film product of claim 16 .
21 . A battery comprising an anode, a cathode, an electrolyte, and a separator situated between the anode and the cathode, the separator comprising:
a microporous polymeric membrane; and
a non-woven web bonded to the polymeric microporous membrane, wherein the web comprises a plurality of fibers comprising polyolefin having a Tm≧85.0° C. and a Te-Tm≦10° C.
22 . The battery of claim 21 , wherein the polyolefin comprises polyethylene having an Mw of 1.5×10 4 to 5.0×10 4 and an MWD of 1.5 to 5.0.
23 . The battery of claim 21 , wherein the polyolefin comprises comonomer, and the copolymer has a CDBI≧50.0%, an Mw of 1.5×10 4 to 5.0×10 4 , an MWD of 1.8 to 3.5, a Tm of 100.0° C. to 126.0° C., and a Te-Tm of 2.0° C. to 4.0° C.
24 . The battery of claim 21 , wherein the separator has a normalized air permeability≦1.0×10 3 sec/100 cm 3 /20 μm, a porosity≧25%, and a normalized pin puncture strength≧3.0×10 3 mN/20 μm.
25 . The battery of claim 21 , wherein the battery is a lithium ion secondary battery.