The resin composition according to one aspect is a resin composition containing a polyamic acid and a solvent, wherein the polyamic acid has a repeating unit represented by the following general formula (1) in a molecular chain, and the molecular chain has a structure represented by the following general formula (2) at one end or both ends. The proportion of the structure represented by the following general formula (2) relative to 1 mol of the repeating unit represented by the following general formula (1) is 0.001 mol or more and 0.1 mol or less. In the following general formulas, R.sup.1 is a tetravalent organic group; R.sup.2 is a divalent organic group; and R.sup.3 is an organic group having 15 or less carbon atoms.

##STR00001##

A polyimide copolymer according to an embodiment of the present disclosure includes a plurality of structural units. The plurality of structural units include a structural unit derived from dianhydride having an alicyclic structure and a structural unit derived from aromatic diamine including an ether group, thereby mechanical properties, thermal stability and optical characteristics of the polyimide film may be improved.

In a first aspect, a polymer film includes a polyimide. The polyimide includes one or more dianhydrides and one or more diamines. Each of the dianhydrides and diamines is selected from the group consisting of crankshaft monomers, flexible monomers, rigid rotational monomers, rigid non-rotational monomers, and rotational inhibitor monomers. The polymer film has a D.sub.f of 0.005 or less, a water absorption of 2.0% or less and a water vapor transport rate of 50 (g×mil)/(m.sup.2×day) or less. In a second aspect, a metal-clad laminate includes the polymer film of first aspect and a first metal layer adhered to a first outer surface of the polymer film. In a third aspect, an electronic device includes the polymer film of the first aspect.

Provided is a layered product that uses a high temperature-resistant transparent film having sufficient heat resistance, and that is capable of being mechanically released from an inorganic substrate after various processes are performed on the inorganic substrate since the adhesive strength between the high temperature-resistant transparent film and the inorganic substrate is appropriately weak, and that is less warped along with the inorganic substrate. In this layered product, no adhesive is used between the high temperature-resistant transparent film and the inorganic substrate, the release strength between the high temperature-resistant transparent film and the inorganic substrate is at most 0.3 N/cm, and the warpage amount of the layered product when heated at 300° C. is at most 400 .Math.m.

According to the present invention, a power module that has a base to which a power semiconductor device is bonded and a sealing body for sealing said base and in which the base and the sealing body are bonded with a primer layer interposed therebetween, said primer layer being formed of a cured product of a silicone-modified polyimide resin composition containing, for example, components (A) to (E) below, has high reliability because delamination of an epoxy sealing resin under high temperature conditions is suppressed. (A) Silicone-modified polyimide resin represented by formula (1)
Ee-Ff-Gg  (1)
E is represented by formula (2), F is represented by formula (3), G is a divalent group derived from diamine, f+e+g=100 mol %, the molar ratio f/(e+g) is 0.9-1.1, and e is 1-90 when the sum of e and g is 100. ##STR00001##
R.sup.A is a divalent hydrocarbon group, R.sup.1 and R.sup.2 are alkyl groups, R.sup.3 and R.sup.4 are monovalent aliphatic hydrocarbon groups, R.sup.5 and R.sup.6 are aryl groups or the like, m is an integer of 0-20, n is an integer of 1-20, o is an integer of 0-20, and m+n+o is an integer of 1-30.
-Im-X-Im-  (3)
Im is a cyclic group including a cyclic imide structure, and X is a single bond or the like. (Bc) Heat-decomposable radical initiator (C) Solvent (D) Antioxidant (E) Fumed silica.

According to the present invention, a power module that has a base to which a power semiconductor device is bonded and a sealing body for sealing said base and in which the base and the sealing body are bonded with a primer layer interposed therebetween, said primer layer being formed of a cured product of a silicone-modified polyimide resin composition containing, for example, components (A) to (E) below, has high reliability because delamination of an epoxy sealing resin under high temperature conditions is suppressed. (A) Silicone-modified polyimide resin represented by formula (1)
Ee-Ff-Gg  (1)
E is represented by formula (2), F is represented by formula (3), G is a divalent group derived from diamine, f+e+g=100 mol %, the molar ratio f/(e+g) is 0.9-1.1, and e is 1-90 when the sum of e and g is 100. ##STR00001##
R.sup.A is a divalent hydrocarbon group, R.sup.1 and R.sup.2 are alkyl groups, R.sup.3 and R.sup.4 are monovalent aliphatic hydrocarbon groups, R.sup.5 and R.sup.6 are aryl groups or the like, m is an integer of 0-20, n is an integer of 1-20, o is an integer of 0-20, and m+n+o is an integer of 1-30.
-Im-X-Im-  (3)
Im is a cyclic group including a cyclic imide structure, and X is a single bond or the like. (Bc) Heat-decomposable radical initiator (C) Solvent (D) Antioxidant (E) Fumed silica.

The invention relates to an imide polymer-based solid film lubricant, a method for producing same, a sliding element comprising same and the use thereof. According to the method, difunctional or cyclized difunctional compounds and optionally functional fillers are added to a non-imidized or partly imidized polyamide acid prepolymer or an imidized short-chain blocked prepolymer in a solvent or solvent mixture and then, depending on the prepolymer, a polymerization reaction or an imidization reaction and in both cases a crosslinking reaction is carried out. The solid film lubricant comprises an imide polymer as the resin matrix and optionally functional fillers, the molecules of the imide polymer comprising groups (R.sub.1) of the difunctional compounds that additionally contribute to the crosslinking.

The invention relates to an imide polymer-based solid film lubricant, a method for producing same, a sliding element comprising same and the use thereof. According to the method, difunctional or cyclized difunctional compounds and optionally functional fillers are added to a non-imidized or partly imidized polyamide acid prepolymer or an imidized short-chain blocked prepolymer in a solvent or solvent mixture and then, depending on the prepolymer, a polymerization reaction or an imidization reaction and in both cases a crosslinking reaction is carried out. The solid film lubricant comprises an imide polymer as the resin matrix and optionally functional fillers, the molecules of the imide polymer comprising groups (R.sub.1) of the difunctional compounds that additionally contribute to the crosslinking.

An embodiment relates to a composition for forming a polyimide film for a cover window capable of satisfying advanced performance required for a cover window, a process for preparing the same, and uses thereof. According to an embodiment, by providing a polyimide film for a cover window for use in optical applications because the polyimide film has no optical stains, implements excellent visibility, and implements excellent heat resistance and mechanical properties without deteriorating colorless and transparent optical properties. The polyimide film may be usefully used in various types of flexible display devices.

An embodiment relates to a composition for forming a polyimide film for a cover window capable of satisfying advanced performance required for a cover window, a process for preparing the same, and uses thereof. According to an embodiment, by providing a polyimide film for a cover window for use in optical applications because the polyimide film has no optical stains, implements excellent visibility, and implements excellent heat resistance and mechanical properties without deteriorating colorless and transparent optical properties. The polyimide film may be usefully used in various types of flexible display devices.