Abstract: This disclosure relates to a polyamideimide resin containing a structure represented by formula (1):

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: [Object] To provide a flexible metal-clad laminate having excellent heat resistance, flexibility and low thermal expansion together with sufficient colorless transparency and a flexible printed circuit board using the same. [Constitution] A colorless and transparent flexible metal-clad laminate where metal foil is directly laminated or is laminated via an adhesive layer on at least one side of the polyamideimide resin layer in which cyclohexane tricarboxylic acid anhydride is a main monomer, characterized in that said polyamideimide resin has an inherent viscosity of 0.8 dl/g or more and 2.5 dl/g or less.

Abstract: Disclosed are a flexible metal-clad laminate comprising a metal foil and a heat-resistant resin film layer formed on one side of the metal foil, the heat-resistant resin film layer comprising a crosslinked condensation polymer and having an N-methyl-2-pyrrolidone-insolule content of at least 1%, and a method for producing the flexible metal-clad laminate comprising the steps of applying a heat-resistant resin solution to a metal foil; predrying the metal foil until the heat-resistant resin layer has an residual solvent content of 10 to 40% by weight; and carrying out solvent removal and heat-treatment while controlling the crosslinking reaction of the resin.

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: Disclosed are a flexible metal-clad laminate comprising a metal foil and a heat-resistant resin film layer formed on one side of the metal foil, the heat-resistant resin film layer comprising a crosslinked condensation polymer and having an N-methyl-2-pyrrolidone-insolule content of at least 1%, and a method for producing the flexible metal-clad laminate comprising the steps of applying a heat-resistant resin solution to a metal foil; predrying the metal foil until the heat-resistant resin layer has an residual solvent content of 10 to 40% by weight; and carrying out solvent removal and heat-treatment while controlling the crosslinking reaction of the resin.

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 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: Disclosed are a flexible metal-clad laminate comprising a metal foil and a heat-resistant resin film layer formed on one side of the metal foil, the heat-resistant resin film layer comprising a crosslinked condensation polymer and having an N-methyl-2-pyrrolidone-insolule content of at least 1%, and a method for producing the flexible metal-clad laminate comprising the steps of applying a heat-resistant resin solution to a metal foil; predrying the metal foil until the heat-resistant resin layer has an residual solvent content of 10 to 40% by weight; and carrying out solvent removal and heat-treatment while controlling the crosslinking reaction of the resin.

Abstract: The present invention provides polyamide-imide fibers for a bag filter comprising a polyamide-imide resin produced by reacting an isocyanate component and an acid anhydride component, the isocyanate component comprising 4,4'-diphenylmethane diisocyanate in an amount of at least 60 mol % of the isocyanate component.