Abstract:
PROBLEM TO BE SOLVED: To provide a separation membrane excellent in rigidity, perviousness, quality stability and thermal stability. SOLUTION: This separation membrane is a polyolefin-based two- or three-layered microporous film composed by combining a layer comprising polyethylene which is produced by a wet process and has the melting point of ≥125°C, with a layer comprising 20-70 wt.% of polypropylene which is produced by a dry process and has a melting point of ≥160°C and 80-30 wt.% of a heat-resistant filler. The micropore in the layer comprising polyethylene is made through the stretching/extraction process and its average size is ≤0.1 μm. The macropore in the layer comprising polypropylene and the heat-resistant filler is formed by the interfacial expansion therebetween and has an average pore size of ≥1 μm but ≤50 μm, film thickness of 9-30 μm, perforation strength of ≥0.15 N/μm, permeability of ≥1.5×10 -5 Darcy and melt fracture temperature of ≥170°C. COPYRIGHT: (C)2009,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide a method for simply producing porous polyimide fine particles in good reproducibility. SOLUTION: This method for producing the porous polyimide fine particles comprises dissolving a polyamic acid containing an alkali metal salt in an amount of 0.5 to 80wt.% based on the polyamic acid in a good solvent selected from organic polar solvents in a concentration of 0.1 to 15wt.%, pouring the obtained polymer solution in a poor solvent selected from aliphatic solvents, alicyclic solvents, aromatic solvents, CS 2 and the mixtures of the solvents and controlled to a temperature of -20 to 60°C to form the porous polyamic acid fine particles having particle diameters of 50 to 10,000nm and having pour diameters of 20 to 500nm and a porosity of 0.1 to 30% which are controlled with the content and kind of the alkali metal salt, and then subjecting the polyamic acid particles to a chemical imidization reaction or a thermal imidization reaction or to the chemical imidization reaction and then to the thermal imidization reaction. Thus, the porous polyimide fine particles holding the above-described pore diameters and porosity is produced. COPYRIGHT: (C)2004,JPO&NCIPI
Abstract:
Provided is a microporous material, e.g., a microporous sheet material, having a matrix of polyolefin, finely-divided, substantially water insoluble particulate filler, a network of interconnecting pores communicating throughout the microporous material, and at least one retrospectively identifiable taggant material embedded within the matrix, optionally the at least one taggant being unique to an end user for the microporous material, wherein the polyolefin is present in the microporous material in an amount of 20 to 35 weight percent, based on the weight of the microporous material. The taggant material provides a marker, signature or code that is capable of retrospective identification by machine, instrument or by the naked eye. Articles including the microporous material and processes for preparing the microporous material also are provided.
Abstract:
Provided is a microporous material, e.g., a microporous sheet material, having a matrix of polyolefin, finely-divided, substantially water insoluble particulate filler, a network of interconnecting pores communicating throughout the microporous material, and at least one retrospectively identifiable taggant material embedded within the matrix, wherein the polyolefin is present in the microporous material in an amount of 20 to 60 weight percent, based on the weight of the microporous material. The taggant material provides a marker, signature or code that is capable of retrospective identification by machine, instrument or by the naked eye. Articles including the microporous material and processes for preparing the microporous material also are provided.