Provided is a varnish for the formation of a charge-transporting thin film, said varnish including an organic solvent, a charge-transporting substance, and a 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative represented by formula (T1)

##STR00001##

(in the formula, each R.sup.A independently represents a C1-20 alkyl group, and R.sup.B represents a hydrogen atom, a hydroxy group, an amino group, a carboxyl group, a cyano group, an oxo group, an isocyanato group, a C1-20 alkoxy group, a C2-20 alkylcarbonyloxy group, a C7-20 arylcarbonyloxy group, a C2-20 alkylcarbonylamino group or a C7-20 arylcarbonylamino group).

Provided is a varnish for the formation of a charge-transporting thin film, said varnish including an organic solvent, a charge-transporting substance, and a 2,2,6,6-tetraalkylpiperidine-N-oxyl derivative represented by formula (T1)

##STR00001##

(in the formula, each R.sup.A independently represents a C1-20 alkyl group, and R.sup.B represents a hydrogen atom, a hydroxy group, an amino group, a carboxyl group, a cyano group, an oxo group, an isocyanato group, a C1-20 alkoxy group, a C2-20 alkylcarbonyloxy group, a C7-20 arylcarbonyloxy group, a C2-20 alkylcarbonylamino group or a C7-20 arylcarbonylamino group).

A resin composition includes: a vinyl-containing polyphenylene ether resin; a compound of Formula (1); and a compound of Formula (2), a compound of Formula (3), a compound of Formula (4) or a combination thereof. The resin composition may be used to make various articles, such as a prepreg, a resin film, a laminate or a printed circuit board, and at least one of the following improvements can be achieved, including prepreg viscosity variation ratio, prepreg stickiness resistance, amount of void after lamination, multi-layer board thermal resistance, glass transition temperature, ratio of thermal expansion, copper foil peeling strength, dissipation factor and laminate appearance.

A resin composition includes: a vinyl-containing polyphenylene ether resin; a compound of Formula (1); and a compound of Formula (2), a compound of Formula (3), a compound of Formula (4) or a combination thereof. The resin composition may be used to make various articles, such as a prepreg, a resin film, a laminate or a printed circuit board, and at least one of the following improvements can be achieved, including prepreg viscosity variation ratio, prepreg stickiness resistance, amount of void after lamination, multi-layer board thermal resistance, glass transition temperature, ratio of thermal expansion, copper foil peeling strength, dissipation factor and laminate appearance.

Provided is a resist underlayer film-forming composition that is used in a lithographic process in semiconductor manufacturing and has excellent storage stability. The resist underlayer film-forming composition contains: a polymer having a disulfide bond in a main chain; a radical trapping agent; and a solvent. The radical trapping agent is preferably a compound having a ring structure or a thioether structure. The ring structure is preferably an aromatic ring structure having 6-40 carbon atoms or a 2,2,6,6-tetramethylpiperidine structure.

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.

An additive article stabilizing method includes prior to polymerization, adding a radiation-activated stabilizing composition to a liquid resin, forming the article from the liquid resin, layer by layer, using radiation such that the stabilizing composition does not stabilize the liquid resin but the formed article, and neutralizing free radicals generated during a degradation process initiated by exposure of the article to additional radiation post-cure.

An additive article stabilizing method includes prior to polymerization, adding a radiation-activated stabilizing composition to a liquid resin, forming the article from the liquid resin, layer by layer, using radiation such that the stabilizing composition does not stabilize the liquid resin but the formed article, and neutralizing free radicals generated during a degradation process initiated by exposure of the article to additional radiation post-cure.

Provided is a flexible tube, for an endoscope, having a flexible tube substrate, for an endoscope, that is flexible and tubular and a resin layer covering the flexible tube substrate for an endoscope. The resin layer includes one or more layers, the layers including a layer A including a polyester elastomer (a) as a resin component, a hindered amine compound (b), and a particular compound (c). Also provided are an endoscopic medical device including the flexible tube for an endoscope and a resin composition and a set of resin compositions that are suitable for forming the resin layer of the flexible tube for an endoscope.