Abstract: An insulating coating material is provided herein. In some embodiments, the insulating coating material comprises an insulating film comprising a polyimide resin, wherein the insulating film, when measuring a tensile elasticity in accordance with ASTM D882, having a stress at 5% strain of 180 MPa or greater and a stress at 15% strain of 225 MPa or greater, wherein the stress at 15% strain is greater than the stress at 5% strain.

Abstract: In the present invention, (i) a polyamic acid solution for forming a thermoplastic polyimide layer to be in no contact with a support contains no chemical dehydrating agent or imidization catalyst, (ii) a polyamic acid solution for forming a thermoplastic polyimide layer to be in contact with the support contains an imidization catalyst, and (iii) a polyamic acid solution for forming a non-thermoplastic polyimide layer contains a chemical dehydrating agent and an imidization catalyst. This arrangement eliminates a property difference between the thermoplastic polyimide layers.

Abstract: Provided are a multilayer polyimide film that hardly suffers from the peeling of the layers from each other or the clouding of a space between the layers (turning white in color) during heating at a high temperature and a flexible metal-clad laminate using such a multilayer polyimide film. This object can be attained by a multilayer polyimide film having a thermoplastic polyimide layer on at least one side of a nonthermoplastic polyimide layer, wherein at least 60% of the total number of moles of an acid dianhydride monomer and a diamine monomer that constitute the thermoplastic polyimide is the same type of monomer as at least one type of acid dianhydride monomer and at least one type of diamine monomer that constitute the nonthermoplastic polyimide.

Abstract: A film and a flexible metal-clad laminate obtained with the film. The laminate is improved in post-moisture absorption solderability. The film comprises a heat-resistant polyimide film and, disposed on at least one side thereof, an adhesive layer containing a thermoplastic polyimide. It is characterized in that the thermoplastic polyimide contained in the adhesive layer has crystallinity and that the film, when analyzed with a differential scanning calorimeter, has an endothermic peak attributable to the melting of the crystalline thermoplastic polyimide, the absolute value of the area of the peak being 4.0 mJ/mg or larger. The flexible metal-clad laminate is characterized by comprising the film and a metal layer disposed thereon.