A cross-linked SBR microsphere binder and a preparation method, and a lithium-ion battery containing the binder, the cross-linked SBR microsphere binder has a porous cross-linked structure, the cross-linked SBR microsphere has a particle size of 10 nm-1 μm, and a porosity of 0.01%-40%, and a pore diameter of the pore is greater than 0 and less than or equal to 200 nm. The lithium-ion battery containing the binder has advantages of better rate performance, low temperature performance, fast charge performance, and long cycle performance, compared with a lithium-ion battery containing a conventional SBR binder.

A method for preparing core/shell particles includes forming a suspension of ethylenically unsaturated monomer droplets containing one or more monomers and a porogen in an aqueous medium containing a first stabilizer and a polymerization initiator, wherein at least one of the monomers is a cross-linking monomer, and wherein the first stabilizer is an inorganic colloid. The method further includes polymerizing the one or more monomers to form core/shell particles having a core of a porous polymer and a polymeric shell having a shell thickness of at least 5 nm, wherein any pores in the polymeric shell have a diameter of less than 2 nm.

Provided is a separator for a non-aqueous secondary battery, the separator contains a porous substrate, and a heat resistant porous layer that is provided on one side or on both sides of the porous substrate, and that contains a heat resistant resin and barium sulfate particles, in which an average primary particle size of the barium sulfate particles contained in the heat resistant porous layer is from 0.01 μm to less than 0.30 μm, and in which a volume ratio of the barium sulfate particles in a solid content portion of the heat resistant porous layer is from 5% by volume to less than 30% by volume.

A resin microparticle production method includes a step of pulverizing resin particles having a thermoplastic resin as a forming material and having a BET specific surface area of equal to or more than 5 m.sup.2/g using an impact type pulverizer.

[Problem to be Solved]

Provided is a polyvinylidene fluoride resin-made porous membrane having excellent hydrophilicity, permeability, and fouling resistance and having suppressed elution of vinyl ether copolymer by using a small amount of vinyl ether copolymer.

[Means to Solve the Problem]

The porous membrane according to the invention comprises a polyvinylidene fluoride resin as a matrix material and a vinyl ether copolymer, wherein the vinyl ether copolymer is a copolymer of an oxyethylene group-containing vinyl ether monomer and a hydrocarbon group-containing vinyl ether monomer.

A membrane filter is provided. The membrane filter including an ordered functional nanoporous material (OFNM) defining a layer and a membrane support. The layer having a two-dimensional structure and defining a plurality of pores and imparting to the membrane filter a permeance of at least 900 Lm.sup.−2h.sup.−1bar.sup.−1 and a rejection of at least 60% as to a solvent containing a filterable species.

A method for producing a porous material includes processing a urethane resin composition containing a urethane resin (A) and a solvent (B) by a wet film forming process, in which the solvent (B) satisfies the following conditions: a difference between a Hansen solubility parameter of the solvent (B) (B-HSP) and a Hansen solubility parameter of the urethane resin (A) (A-HSP) is in the range of 3 to 8 (J/cm.sup.3).sup.1/2 and a difference between the Hansen solubility parameter of the solvent (B) (B-HSP) and a Hansen solubility parameter of water (W-HSP) is in the range of 31.5 to 38 (J/cm.sup.3).sup.1/2. The Hansen solubility parameter of the solvent (B) preferably has a dispersion term (δD) in the range of 15.5 to 21.0 MPa.sup.0.5, a polar term (δP) in the range of 7.0 to 14.5 MPa.sup.0.5, and a hydrogen bond term (δH) in the range of 4.5 to 11.0 MPa.sup.0.5.

Provided are: a porous polyether sulfone film having macrovoids and having excellent dimensional stability; and a production method therefor. Provided is a porous polyether sulfone film having a surface layer (a), a surface layer (b), and a macrovoid layer interposed between the surface layer (a) and the surface layer (b). The macrovoid layer has a partition wall joined to the surface layers (a) and (b) and a plurality of macrovoids surrounded by the partition wall and the surface layers (a) and (b). The surface layer (a) and the surface layer (b) have pores connected to the macrovoids.

A method for producing a porous material includes processing a urethane resin composition containing a urethane resin (A) and a solvent (B) by a wet film forming process, in which the solvent (B) satisfies the following conditions: a difference between a Hansen solubility parameter of the solvent (B) (B-HSP) and a Hansen solubility parameter of the urethane resin (A) (A-HSP) is in the range of 3 to 8 (J/cm.sup.3).sup.1/2 and a difference between the Hansen solubility parameter of the solvent (B) (B-HSP) and a Hansen solubility parameter of water (W-HSP) is in the range of 31.5 to 38 (J/cm.sup.3).sup.1/2. The Hansen solubility parameter of the solvent (B) preferably has a dispersion term (δD) in the range of 15.5 to 21.0 MPa.sup.0.5, a polar term (δP) in the range of 7.0 to 14.5 MPa.sup.0.5, and a hydrogen bond term (δH) in the range of 4.5 to 11.0 MPa.sup.0.5.

The present invention pertains to a porous polyimide film production method and a porous polyimide film produced using said method, said method including: a step (1) in which a poly(amic acid) solution comprising 40%-97% by mass organic polar solvent and 3%-60% by mass poly(amic acid) having an intrinsic viscosity, comprising tetracarboxylic acid units and diamine units, of 1.0-3.0 is cast in film form and immersed in or caused to come in contact with a coagulating solvent having water as an essential component thereof, and a porous film of poly(amic acid) is produced; and a step (2) in which the porous film of poly(amic acid) obtained in said step is heat treated and imidized. Shrinkage in the film longitudinal direction and transverse direction after heat treatment is suppressed to no more than 8% for each direction and the speed of temperature increase in a temperature range of at least 200° C. during the heat treatment is at least 25° C./min.