TECHNOLOGY FOCUS - POLYMERS - Preferred Group: The cation polymerizable functional group is at least 1 type chosen from 3-oxetanyl group and an epoxy group. Preferred Polymer: The cross linkable polymer is radical copolymer of radically polymerizable monomer which has at least 1 type of cation polymerizable functional group chosen from radically polymerizable monomer which has 3-oxetanyl group, radically polymerizable monomer which has an epoxy group, radically polymerizable monomer which has a reactive group which reacts with respect to an isocyanate group, and an another radically polymerizable monomer. The cross-linkable polymer is a radical polymer with 5-50 wt.% of radically polymerizable monomers which have radically polymerizable monomer which has 3-oxetanyl group based on total amount of monomers, and/or an epoxy group, and 0.1-10 wt.% of radically polymerizable monomers and an another radically polymerizable monomer which has a reactive group which reacts with respect to an isocyanate group. The reactive polymer has 5-80% of insoluble-content rate. The radically polymerizable monomer which has he reactive group which may react with respect to an isocyanate group is hydroxyl alkyl (meth)acrylate. The radically polymerizable monomer which has 3-oxetanyl group is 3-oxetanyl group containing (meth)acrylate of formula (I).R1 = hydrogen atom o methyl group;andR2 = hydrogen atom or 1-16C alkyl group.The radically polymerizable monomer which has an epoxy group is of formula (II) or epoxy group-containing meth(acrylate) with epoxy group-containing group of formula (1,2).An another radically polymerizable monomer is at least 1 type of monomer chosen from (meth)acrylate of formula (III) and vinyl ester of formula (IV).R5 = hydrogen atom or methyl group;A = 2 or 3C oxyalkylene group;R6 = 1-6C alkyl group or 1-6C fluorinated alkyl group;n = 0-3;R7 = methyl group or an ethyl group;andR8 = hydrogen atom or a methyl group.Preferred Properties: The base material porous film has thickness of 3-50 mum, and porosity of 20-95%.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Catalyst: The cation polymerization catalyst is an onium salt. The electrolyte liquid contains at least one type chosen from lithium hexafluoro-phosphate and a lithium tetrafluoroborate as an electrolyte salt which serves as a cation polymerization catalyst. EXAMPLE - Cross-linkable polymer (A) having weight average molecular weight of 30800, 5 wt.% of hydroxy ethyl methacrylate monomer compounds, and 25 wt.% of 3-oxetanyl group-containing monomer components, was prepared by radical polymerizing methyl methacrylate, methyl methacrylate (3-ethyl-3-oxetanyl)n 2-hydroxy ethyl methacrylate, ethylacetate and N,N'-azobisisobutyronitrile. The obtained cross-linkable polymer (in g) (10) was added to ethyl acetate (90) and stirred at room temperature, and uniform cross-linkable polymer solution was obtained. Polyfunctional isocyanate Coronate HL (1.02) was added to the cross-linkable polymer solution as a cross-linking agent and stirred and dissolved at room temperature. The solution of cross-linkable polymer containing cross-linking agent was coated on both surface of polyethyl rein porous film base material with thickness of 16 mum, porosity of 40%, permeability of 300 seconds/100 cc and adhesion of 3 N. The coating was heat dried at 50degreesC and ethyl acetate was vaporized and cross-linkable polymer containing porous film was obtained with application density of 3g/m2 and application thickness of 2.5 mum per one surface. Subsequently, the obtained porous film was maintained in 50degreesC humidistat for 48 hours. Hydroxy ethyl methacrylate component in the cross-linkable contained was reacted with the cross-linking agent, and a portion of the cross-linkable polymer was cross-linked. The reactive polymer containing porous film was obtained. The insoluble content rate of the reactive polymer was 35%. The lamination seal type battery was obtained by using the obtained porous film, anode, cathode and separator with electrolyte liquid. The obtained battery had 95% of discharge capacitance. The adhesive powder between anode and the separator was 0.3 N/cm and between cathode and separator was 0.15 N/cm.