Abstract: For instance, when a washing-free yet low-residue type of flux is coated on a solder resist film, soldering can be carried out while no solder balls remain on a circuit substrate.A photosensitive resin composition comprises a photopolymerizable and photosensitive resin having at least one of a carboxyl group and an onium group, a photopolymerizable reactive diluent, a photopolymerization initiator, a thermosetting component, and an inorganic powder having an average particle size of 2 .mu.m to 20 .mu.m. A cured film thereof is used as a solder resist film for circuit substrate fabrication.A washing-free yet low-residue type of flux is so uniformly coated on the solder resist film that soldering can be carried out in the absence of any solder ball.

Abstract: The invention provides a soldering flux for mounting circuit substrates, which is free from any organic solvent attributable to air pollution and dispenses with any washing step. The soldering flux is obtained by dissolving a rosin modified by an unsaturated organic acid according to the Diels-Alder reaction in an aqueous solvent. A volatile basic agent may further be contained in the flux.

Abstract: For instance, when a washing-free yet low-residue type of flux is coated on a solder resist film, soldering can be carried out while no solder balls remain on a circuit substrate.A photosensitive resin composition comprises a photopolymerizable and photosensitive resin having at least one of a carboxyl group and an onium group, a photopolymerizable reactive diluent, a photopolymerization initiator, a thermosetting component, and an inorganic powder having an average particle size of 2 .mu.m to 20 .mu.m. A cured film thereof is used as a solder resist film for circuit substrate fabrication.A washing-free yet low-residue type of flux is so uniformly coated on the solder resist film that soldering can be carried out in the absence of any solder ball.

Abstract: The present invention relates to a photopolymerizable composition; more specifically, the present invention relates to a photopolymerizable composition useful as photoimageable solder mask of one component type, which can form image by ultraviolet exposure and development in an aqueous solution of dilute alkali after film formation and which has excellent ultraviolet curability and heat resistance of solder. The composition contains a reaction product, a diluent and a sensitizer, the reaction product being produced by adding epoxy group-containing acrylic acid ester or epoxy group-containing methacrylic acid ester to a part of the carboxyl group of the copolymer of acrylic acid ester or methacrylic acid ester with acrylic acid or methacrylic acid.

Abstract: The present invention provides a photopolymerizable composition useful as a liquid photoimageable solder mask comprising (a) a reaction product obtained by reacting epoxy resin A containing at least two terminated epoxy groups with 0.8 to 1.2 mol, per 1 epoxy equivalent of epoxy resin A, of an .alpha.,.beta.-unsaturated carboxylic acid and then reacting same with 0.2 to 1.0 mol, per 1 epoxy equivalent of epoxy resin A, of polybasic acid anhydride, (b) diluent, (c) sensitizer, (d) epoxy resin B consisting of tris (2,3-epoxypropyl) isocyanurate whose melting point is 130.degree. C. or less, and (e) an epoxy resin curing agent represented by the general formula [I:] ##STR1## wherein R is --H, halogen, --NH.sub.2, --SH, aromatic hydrocarbon, a C.sub.1 -C.sub.4 alkyl group or NHR' (R' is a C.sub.1 -C.sub.4 alkyl group having --CN or NH.sub.2 C.dbd.NH).

Abstract: A solder powder is coated with an agent that protects the powder from oxidation. The coating agent is substantially insoluble in a vehicle used to make solder pastes. Thus, pastes made with the coated powders also resist oxidation even when exposed to air. A method for making the coated solder powders is also disclosed and claimed.

Abstract: A soldering device wherein the article to be soldered is moved into contact with molten solder which flows in the direction counter to the direction of movement of said article is characterized by including a nozzle for flowing said molten solder and a flow path of a channel shape provided contiguous thereto for circulating said molten solder flowed out of said nozzle, said flow path having side-wall plates which are vertically adjustable.

Abstract: The present invention provides a photosensitive resin composition comprising (a) 10-60 wt. % of a styrene--maleic acid copolymer or its partially esterified product having a molecular weight of 1,000-3,000 and an acid value of 50-500, (b) 1-30 wt. % of acrylate or methacrylate having a tetrahydrofurfuryl group or a hydroxyl group, (c) 1-30 wt. % of diacrylate or dimethacrylate of polyethyleneglycol or polypropylene glycol, (d) 1-40 wt. % of a monoester compound represented by the following general formula (I), (II), (III), (IV) or (V). ##STR1## (wherein, X stands for a divalent organic group, preferably an alkylene group having carbon atoms of 1-4 or --C.sub.n H.sub.2n O--.sub.p CH.sub.2 group wherein n is an integer of 2-6 and p is an integer of 1-19; Y stands for hydrogen atoms or a methyl group; and Y' stands for hydrogen atoms or an alkyl group having carbon atoms of 1-4.).

Abstract: A photosensitive composition comprising polyester, a half-esterified hydroxy alkyl acrylate (or methacrylate) of polybasic acid (or its anhydride), an ethylenic unsaturated bond-having vinyl monomer and a photo-polymerization initiator is especially useful for processing printed circuit boards.

Abstract: A photopolymerizable ink composition containing as essential ingredients (A) a high molecular diacrylate of epoxy resin made of bisphenol A and epichlorohydrin, (B) a urethane modified acrylate resin, (C) a urethane bond-free bifunctional photopolymerizable methacrylate monomer or oligomer, (D) a urethane bond-free polyfunctional photopolymerizable acrylate monomer or oligomer and (E) a photo-initiator, is curable upon short time exposure to ultra-violet irradiation and possesses the electrical, mechanical and chemical properties indispensable to a protective film for use in printed circuit boards.