Provided are a separator capable of being used for a secondary battery such as a nonaqueous electrolyte-solution secondary battery and a secondary battery including the separator. A separator having a first layer including a porous polyethylene and an organic additive is provided. A white index of the first layer is equal to or more than 85 and equal to or less than 98, and a reduction rate of diethyl carbonate dropped on the first layer is equal to or higher than 0.048 mg/s and equal to or lower than 0.067 mg/s. The separator may further include a porous layer over the first layer.

Compositions for forming porous materials and three-dimensional objects, including fibers, films and coatings made from the materials are provided. Also provided are methods for forming the porous objects from the compositions. The compositions include a solvent, a polymer binder that is soluble in the solvent, and solid particles that are insoluble in the solvent. The solid particles include water-soluble salt particles that can be selectively dissolved from objects made from the compositions to render the resulting structures porous.

Compositions for forming porous materials and three-dimensional objects, including fibers, films and coatings made from the materials are provided. Also provided are methods for forming the porous objects from the compositions. The compositions include a solvent, a polymer binder that is soluble in the solvent, and solid particles that are insoluble in the solvent. The solid particles include water-soluble salt particles that can be selectively dissolved from objects made from the compositions to render the resulting structures porous.

A filtration method that includes a cleaning step using a chemical agent, wherein provided is the filtration method with excellent chemical resistance performance. The filtration method pertaining to the present invention comprises a filtration step in which a liquid to be filtered is filtered by being passed through a porous membrane formed of a resin, and a cleaning step in which the membrane interior of the porous membrane is cleaned after the filtration step, wherein a porous membrane for which the area ratio of a resin part having an area of 1 m.sup.2 or less included in a cross section of the membrane interior is at least 70% of the total area of the entire resin part included in the cross section, and said cleaning step includes a step in which an aqueous solution of at least 1% sodium hydroxide is passed through the porous membrane.

An insulated electric wire includes a linear conductor and one or a plurality of insulating layers formed on an outer peripheral surface of the conductor. At least one of the one or plurality of insulating layers contains a plurality of pores, outer shells are disposed on peripheries of the pores, and the outer shells are derived from shells of hollow-forming particles having a core-shell structure. A varnish for forming an insulating layer contains a resin composition forming a matrix and hollow-forming particles having a core-shell structure and dispersed in the resin composition. In the varnish, cores of the hollow-forming particles contain a thermally decomposable resin as a main component, and shells of the hollow-forming particles contain a main component having a higher thermal decomposition temperature than the thermally decomposable resin.

An insulated electric wire includes a linear conductor and one or a plurality of insulating layers formed on an outer peripheral surface of the conductor. At least one of the one or plurality of insulating layers contains a plurality of pores, outer shells are disposed on peripheries of the pores, and the outer shells are derived from shells of hollow-forming particles having a core-shell structure. A varnish for forming an insulating layer contains a resin composition forming a matrix and hollow-forming particles having a core-shell structure and dispersed in the resin composition. In the varnish, cores of the hollow-forming particles contain a thermally decomposable resin as a main component, and shells of the hollow-forming particles contain a main component having a higher thermal decomposition temperature than the thermally decomposable resin.

A molded body is produced from a molding material including a continuous phase and a dispersed phase by a three-dimensionalization step, a curing step, and a peeling step. The continuous phase of the molding material is a water phase containing a curable compound. In the three-dimensionalization step, the molding material is placed in a container. In the curing step, the curable compound is cured to form a cured product after the three-dimensionalization step. In the peeling step, the container and the cured product are separated after the curing step. In the dispersed phase removal step, the dispersed phase of the cured product is removed after the curing step.

A molded body is produced from a molding material including a continuous phase and a dispersed phase by a three-dimensionalization step, a curing step, and a peeling step. The continuous phase of the molding material is a water phase containing a curable compound. In the three-dimensionalization step, the molding material is placed in a container. In the curing step, the curable compound is cured to form a cured product after the three-dimensionalization step. In the peeling step, the container and the cured product are separated after the curing step. In the dispersed phase removal step, the dispersed phase of the cured product is removed after the curing step.

A molding device produces a porous film from a molding material which is an emulsion. In a case where a volume of a dispersed phase is X1 and a volume of a continuous phase is X2, the molding material has a value of X1/(X1+X2) within a range of 0.5 or more and 0.9 or less. In the molding material, a specific gravity of the dispersed phase is greater than a specific gravity of the continuous phase. The molding material includes a water phase containing a curable compound as the continuous phase, and forms a liquid film on a support. Thereafter, the curable compound in the liquid film is cured. After curing, the dispersed phase is removed.

A molding device produces a porous film from a molding material which is an emulsion. In a case where a volume of a dispersed phase is X1 and a volume of a continuous phase is X2, the molding material has a value of X1/(X1+X2) within a range of 0.5 or more and 0.9 or less. In the molding material, a specific gravity of the dispersed phase is greater than a specific gravity of the continuous phase. The molding material includes a water phase containing a curable compound as the continuous phase, and forms a liquid film on a support. Thereafter, the curable compound in the liquid film is cured. After curing, the dispersed phase is removed.