Abstract: An object of the present invention is to provide an industrially excellent method for removing lead that is high in removal effect of lead, capable of implementing the removal even in small facilities and of suppressing capital investment cost. A material to be treated selected from the group consisting of a pure metal and an alloy is heated to obtain a melt. The melt is contacted with at least one of a metal halide and a metal oxyhalide to remove lead in the material to be treated.

Abstract: An object of the present invention is to provide a thermosetting resin composition having a low dielectric constant, a low dielectric loss tangent, a low thermal expansion coefficient and an excellent peel strength at a low surface roughness after roughening adapted to additive process. The present invention provides a thermosetting resin composition comprising (a) 100 weight parts of polyfunctional vinyl benzyl ether compound, (b) 1 to 100 weight parts of solvent soluble polyimide resin, and (c) 0.01 to 10 weight parts of a catalyst for thermosetting reaction.

Abstract: A thermosetting resin composition comprises (a) epoxy resin, (b) setting agents comprising a novolak-type phenol resin and a benzooxazine compound and (c) a siloxane-modified polyamide-imide resin satisfying the following relationship. 0.6?m+n?2, 0.5?m?1.2, and 0.1?n?1.0 (“m” represents the hydroxyl group equivalent of (b) said novolak-type phenol resin with respect to the epoxy equivalent of (a) said epoxy resin of 1, and “n” represents the hydroxyl group equivalent of (b) the benzooxazine compound after thermal decomposition with respect to the epoxy equivalent of (a) the epoxy resin of 1. The thermosetting resin composition comprises (c) the siloxane-modified polyamide-imide resin in a content of 2 to 50 weight parts with respect to the total content of (a) the epoxy resin and (b) the setting agents of 100 weight parts.

Abstract: A surface treatment agent is applied onto a metal film of a printed circuit board to form a rust preventive film. The surface treatment agent for metal comprises an aqueous solution comprising an organic acid having a boiling point of 170° C. or higher and one or more compound selected from the group consisting of an imidazole based compound and a benzimidazole based compound.

Abstract: There is provided an in-oil atomization method wherein a solder is fused and dispersed in a heated particle dispersion medium, the method being featured in that even if the quantity of the particle dispersion medium to be employed is relatively small, fine solder particles can be effectively obtained. Namely, this invention provides a method of manufacturing fine particles, wherein solder is fused in the heated particle dispersion medium to obtain a molten solder, which is then dispersed by means of an agitator to obtain molten solder particles which are subsequently cooled and solidify, the method being characterized in that the above dispersing step is performed in the presence of a particle coalescence-preventing agent. This invention also provides a fine metal particles-containing substance and a paste solder composition.

Abstract: There is provided a lead-free solder which makes it possible to reliably and accurately perform the inspection of various kinds of defective soldering in the inspection using an image inspection apparatus after the reflow soldering. According to this lead-free solder, the delustering of the metallic luster of fillet is realized in order to minimize the probability of generating a dark portion at the area where no defective soldering is existed and instead to increase the area of whitish portion which can be generated through the irregular reflection of beam. Specifically, this invention provides a lead-free solder comprising an Sn—Ag—Cu-based lead-free solder containing a small quantity of Bi and Sb as an element which is capable of generating a delustering component for minimizing metallic luster of the fillet.

Abstract: Disclosed is a photosensitive resin composition which can be developed using a dilute aqueous alkaline solution after ultraviolet ray exposure, is excellent in pot life, capable of preventing deposits from being generated in a cured coated film, capable of widening heat control tolerance, and is excellent in sensitivity, in heat resistance, in chemical resistance and in electric insulating properties, thereby rendering the composition suitable for use as a solder resist for producing a printed wiring board. This photosensitive resin composition comprises (A) an active energy ray-curable resin having at least two ethylenic unsaturated linkages per molecule thereof, (B) at least one kind material selected from acid salts of N-substituted melamine compound and acid salts of guanamine compound, (C) a photopolymerization initiator, (D) a diluent, and (E) a thermosetting compound. There is also disclosed a printed wiring board where this photosensitive resin composition is employed.

Abstract: There is provided an in-oil atomization method wherein a solder is fused and dispersed in a heated particle dispersion medium, the method being featured in that even if the quantity of the particle dispersion medium to be employed is relatively small, fine solder particles can be effectively obtained. Namely, this invention provides a method of manufacturing fine particles, wherein solder is fused in the heated particle dispersion medium to obtain a molten solder, which is then dispersed by means of an agitator to obtain molten solder particles which are subsequently cooled and solidify, the method being characterized in that the above dispersing step is performed in the presence of a particle coalescence-preventing agent. This invention also provides a fine metal particles-containing substance and a paste solder composition.

Abstract: Soldering paste for bonding an electronic component to electrodes on a ceramic substrate includes alcohol having at least two OH groups, organic acid, and metallic powder. The electronic component disposed on the electrodes through the soldering paste undergoes a reflow performed in a nitrogen atmosphere. Accordingly, an ester film is formed around the electrodes as a reaction product of the organic acid and the alcohol. The ester film incorporates therein the remaining organic acid and metal salt as its reaction product. As a result, high insulation reliability is provided.

Abstract: There is provided an active energy beam curable composition, which is useful for forming a solder resist film for a printed wiring board, which can be developed through an ultraviolet exposure and a dilute alkali aqueous solution, and is excel lent in heat resistance, adhesivity and chemical resistance. There is also proposed a printed wiring board provided with a cured film of such an active energy beam curable composition. This composition is featured in that it comprises not only an active energy beam curable vinyl copolymer modified resin wherein an epoxy compound having an ethylenic unsaturated group is added to a copolymer comprising styrene, (metha)acrylic acid, and, as an optional component, (metha)acrylate; but also an active energy beam curable bisphenol type epoxyacrylate resin.

Abstract: Described herein is a printed circuit board surface protective agent containing compounds as expressed by Formula I. ##STR1## (herein, Y is a linear or a branched alkyl group having 1 to 20 carbon atoms or (2) ##STR2## X is any of halogen atom, amino group, di-lower alkylamino group, hydroxy group, lower alkoxy group, cyano group, formyl group, acetyl group, benzoyl group, carbamoyl group, carboxyl group, lower alkoxycarbonyl group, or nitro group; X' is any of alkyl group, halogen atom, amino group, di-lower alkylamino group, hydroxy group, lower alcoxy group, cyano group, formyl group, acetyl group, benzoyl group, carbamoyl group, carboxyl group, lower alkoxycarbonyl group or nitro group; n is an integral number from 1 to 4, and X may be either identical or different when n is in a range from 2 to 4. m is an integral number in a range from 1 to 10, p is 0 or an integral number in a range from 1 to 4, and X' may be either identical or different when p is in a range from 2 to 4.

Abstract: Disclosed is a photopolymerizable resin composition suitable for forming a solder mask layer, for example, on a printed circuit board. The photopolymerizable resin composition of the invention can be prepared in the form of an aqueous solution and is developable with water as the developer liquid so that the problems and disadvantages inherent in the use of organic solvents can be completely solved. The composition comprises, in addition to a photopolymerization initiator and a polyenic compound as a reactive diluent, a unique prepolymer as a resinous ingredient which is a copolymer of, for example, an alkyl (meth)acrylate and glycidyl (meth)acrylate modified at the epoxy groups in the copolymer partly by the reaction with (meth)acrylic acid and partly by the reaction with an onium group-containing compound, e.g. a quaternary ammonium compound, to impart solubility in water.