Abstract:
A microporous polymeric film comprises a halopolymer in which the repeating units are -(CnH2n)- and -(CmX2m)- in which each X independently represents fluorine or chlorine and the values of n and m are greater than one and less than six. The film is the result of firstly melt processing a mixture of the halopolymer, an extractable salt and extractable polymer secondly extracting at least some of the extractable salt to render the film porous and extracting at least some of said polymer to impart surface porosity to the film. The film may be used as the separator of an electrochemical cell e.g. a battery having a lithium anode and a thionyl chloride electrolyte. High porosities and good electrical properties can be obtained by using as extractable polymer a material having a molecular weight less than one million e.g. a polyethylene oxide of molecular weight about 100,000 - 300,000. The film may be made in relatively long lengths by addition of an anti-oxidant to the mixture to be melt processed.
Abstract:
PROBLEM TO BE SOLVED: To provide a polyetherimide porous body which has a low relative permittivity and is not susceptible to fractures during folding (has excellent fracture resistance), and a method for producing the same.SOLUTION: This polyetherimide porous body comprises a polyetherimide cross-linked body and has a gel fraction of 10% or more, an average bubble diameter of 8 μm or less, a volume porosity of 30% or more and a dielectric breakdown voltage of 30 kV/mm or more.
Abstract:
PROBLEM TO BE SOLVED: To provide a method for producing a long thermosetting resin porous sheet not having a defective part causing breakage.SOLUTION: A method for producing a thermosetting resin porous sheet includes: a step for cutting a thermosetting resin so as to have a sheet shape having a prescribed thickness by bringing a cutting blade into contact with a thermosetting resin block, while rotating the cylindrical or circularly-columnar thermosetting resin block containing porogen around the axis of the cylinder or the axis of the circular column; and a step for removing porogen from the obtained thermosetting resin sheet to make it porous; wherein cutting is performed, while reciprocating the cutting blade approximately in parallel with a rotary shaft direction of the thermosetting resin block.
Abstract:
PROBLEM TO BE SOLVED: To provide a separator for a nonaqueous electrolytic electricity storage device including an improved epoxy resin porous membrane.SOLUTION: In a separator for a nonaqueous electrolytic electricity storage device, a ratio I/Io between a peak intensity Io of an absorption peak existing at 1,240 cmin an infrared absorption spectrum of an epoxy resin porous membrane and a peak intensity I of a peak existing at 1,240 cmin the infrared absorption spectrum of the epoxy resin porous membrane after the porous membrane has been subjected to acetic anhydride treatment is 1.0 or more and 2.4 or less. The amount of active hydroxyl groups present in the epoxy resin porous membrane can be evaluated by the value of the ratio I/Io.