Abstract: The present invention provides a non-halogen polyamide-imide resin soluble in an amide solvent at a concentration of 10%, the resulting varnish, when stored at 5° C. for 1 month, exhibiting a solution viscosity change ((solution viscosity after 1 month?initial solution viscosity)/initial solution viscosity), expressed as an absolute value, of not greater than 3.0, and the resin having a moisture absorption (25° C., 90% RH, 24 hours) of not greater than 2.0%; a flexible metal-clad laminates using such a resin; and a flexible printed wiring board prepared from such a flexible metal-clad laminate by circuit formation. The flexible metal-clad laminate of the invention does not curl under any conditions, including humid conditions, and exhibits excellent dimensional stability since the heat resistant resin used as an insulation material has low moisture absorption and low thermal expansion coefficient and there is less internal stress in the flexible metal-clad laminate.

Abstract: The present invention provides a composite porous membrane suited for a separator for a battery having excellent ion permeability, low pore blocking temperature, and high membrane breakage temperature by compositing resin porous membranes having different melting points (or softening points) without using a termocompression bonding method or a method of directly applying a solution to the substrate by using a composite porous membrane containing a porous membrane A of a resin having a melting point of 150° C. or less and a porous membrane B of a resin having a glass transition temperature of more than 150° C. integrated with the porous membrane A, wherein both a superficial side of the porous membrane B and an interfacial side with the porous membrane A of the porous membrane B have a three-dimensional network structure.

Abstract: The present invention provides a non-halogen polyamide-imide resin soluble in an amide solvent at a concentration of 10%, the resulting varnish, when stored at 5° C. for 1 month, exhibiting a solution viscosity change ((solution viscosity after 1 month?initial solution viscosity)/initial solution viscosity), expressed as an absolute value, of not greater than 3.0, and the resin having a moisture absorption (25° C., 90% RH, 24 hours) of not greater than 2.0%; a flexible metal-clad laminates using such a resin; and a flexible printed wiring board prepared from such a flexible metal-clad laminate by circuit formation. The flexible metal-clad laminate of the invention does not curl under any conditions, including humid conditions, and exhibits excellent dimensional stability since the heat resistant resin used as an insulation material has low moisture absorption and low thermal expansion coefficient and there is less internal stress in the flexible metal-clad laminate.

Abstract: The present invention provides an inexpensive separator satisfactory in shutdown properties and meltdown properties and having excellent insulating properties. A porous film having a thickness of 5 to 100 ?m, characterized by including a porous layer of a polyamide-imide resin which has a glass transition temperature of 70° C. or higher and an inherent viscosity of 0.5 dl/g or higher and containing a unit represented by the following structural formula (I), the amount of the unit being 20 mol % or more based on all repeating structural units. Also provided is the porous film which is characterized in that the porous polyamide-imide resin layer has an amide bond/imide bond ratio of from 10/90 to 45/55. Further more provided is a lithium-ion secondary cell which contains a positive electrode and a negative electrode which are capable of occluding/releasing lithium ions and either of the porous films disposed as a separator between the electrodes.

Abstract: The present invention provides a non-halogen polyamide-imide resin soluble in an amide solvent at a concentration of 10%, the resulting varnish, when stored at 5° C. for 1 month, exhibiting a solution viscosity change ((solution viscosity after 1 month—initial solution viscosity)/initial solution viscosity), expressed as an absolute value, of not greater than 3.0, and the resin having a moisture absorption (25° C., 90% RH, 24 hours) of not greater than 2.0%; a flexible metal-clad laminates using such a resin; and a flexible printed wiring board prepared from such a flexible metal-clad laminate by circuit formation. The flexible metal-clad laminate of the invention does not curl under any conditions, including humid conditions, and exhibits excellent dimensional stability since the heat resistant resin used as an insulation material has low moisture absorption and low thermal expansion coefficient and there is less internal stress in the flexible metal-clad laminate.

Abstract: The present invention is a heat-resistant film comprising at least any one of a polybenzazole, aramid and polyamideimide produced by introducing a thin film made by a roll, slit or press from a polymer solution sandwiched between at least two supports into a coagulating bath and peeling the supports off in the coagulating bath to effect the coagulation, and a composite ion-exchange membrane having a surface layer consisting of an ion-exchange resin excluding a porous film on the both side of a composite layer formed by impregnating said film with the ion-exchange resin. A heat-resistant film having a combination of excellent heat resistance, mechanical strength, smoothness and interlaminar peeling resistance, especially a microporous heat-resistant film, and a composite ion-exchange membrane employing the same which has an excellent ion conductivity are provided.

Abstract: The present invention provides a non-halogen polyamide-imide resin soluble in an amide solvent at a concentration of 10%, the resulting varnish, when stored at 5° C. for 1 month, exhibiting a solution viscosity change ((solution viscosity after 1 month—initial solution viscosity)/initial solution viscosity), expressed as an absolute value, of not greater than 3.0, and the resin having a moisture absorption (25° C., 90% RH, 24 hours) of not greater than 2.0%; a flexible metal-clad laminates using such a resin; and a flexible printed wiring board prepared from such a flexible metal-clad laminate by circuit formation. The flexible metal-clad laminate of the invention does not curl under any conditions, including humid conditions, and exhibits excellent dimensional stability since the heat resistant resin used as an insulation material has low moisture absorption and low thermal expansion coefficient and there is less internal stress in the flexible metal-clad laminate.