Abstract: The present invention provides a photosensitive resin composition for lithographic printing, which is developable with an alkali developer and exhibits excellent resolusion and excellent print durability. The photosensitive resin composition comprises (a) an alkali-swellable or alkali-soluble binder resin and (b) an oil-soluble diazo resin, wherein the binder resin has an acid value of 5 to 150 and has in molecules a group represented by ##STR1## wherein R.sup.1 represents a phenyl group which may have a substitution, R.sup.2 and R.sup.3, the same or different, represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R.sup.4 represents an alkylene group of which a backbone may be interrupted with an oxygen atom, a cycloalkylene group or a combination thereof, and may have thereon an alkyl group, a hydroxyl group, an oxo (.dbd.O) group or a combination thereof, and a and b independently shows 0 or 1.

Abstract: Disclosed is a photosensitive composition used for offset printing, which provides an offset printing plate with excellent durability and developability. The photosensitive composition comprises:(I) a film-forming binder resin,(II) a photosensitive substance, and(III) a microgel having a particle size of 0.01 to2.0 .mu. prepared by emulsion polymerization using a polymeric emulsifier having an Sp value of 9 to 16.

Abstract: The present invention provides an improved process by which dissolved oxygen is effectively removed from a photosensitive resin layer of a photosensitive resin plate. The process comprises preliminarily exposing the photosensitive resin to light to quench oxygen dissolved in said photosensitive resin layer before conducting a main exposure. The photosensitive resin layer is prepared from a photosensitive resin composition which comprises:(a) a polymer binder,(b) a radically polymerizable monomer,(c) a sensitizing dye, and(d) a photopolymerization initiator which is excited by a light of a different wave length from a light exciting the sensitizing dye.The preliminary exposure is conducted with a light only exciting the sensitizing dye and the main exposure is conducted with a light exciting the photopolymerization initiator.

Abstract: Disclosed is a photosensitive resin plate which effectively prevents dot gain by covering the photosensitive resin layer with a specific matte layer. The photosensitive resin plate comprises a substrate, a photosensitive resin layer formed on the substrate and a resin matte layer formed on the photosensitive resin layer, wherein the resin matte layer contains a polymerization inhibiting material.

Abstract: A water-developable photosensitive resin plate suitable for the manufacture of a relief printing plate having high resistance to water-based inks, high resilience and excellent form stability, which comprises:(A) a copolymer comprising units of (i) an aliphatic conjugated diene monomer (ii) and .alpha., .beta.-ethylenically unsaturated carboxylic acid and (iii) a polyfunctional vinyl monomer, optionally with (iv) a monofunctional vinyl monomer, the content of the aliphatic conjugated diene monomer (i), the .alpha., .beta.-ethylenically unsaturated carboxylic acid (ii), the polyfunctional vinyl monomer (iii) and the monofunctional vinyl monomer (iv) being respectively from about 5 to 95 mol %, from about 1 to 30 mol %, from about 0.1 to 10 mol % and 0 to 70 mol % based on the combination of those monomeric components;(B) a basic nitrogen atom-containing compound;(C) an ethylenically unsaturated monomer; and(D) a photopolymerization initiator.

Abstract: Disclosed is a photosensitive resin composition for flexographic printing which has high water developability and good mechanical strength. The resin composition comprises (A) a partially crosslinked copolymer prepared by a radical emulsion polymerization of a specific monomer mixture (B) a linear polymer having a molecular weight of at least 5,000, which has at least 30 mol % of a conjugated diene unit, (C) a basic nitrogen atom-containing compound, (D) a photopolymerizable ethylenically unsaturated monomer, and (E) a photopolymerization inhitiator. The present invention also provides a resin plate for flexographic printing obtained from the above mentioned resin composition and a process for preparing it. The present invention further provides a printing plate obtained from the resin plate and a process for preparing it.

Abstract: Disclosed is a photosensitive flexographic resin plate having excellent wear resistance and giving relief image faithful to a negative film. The photosensitive flexographic printing plate is composed of a base plate and a photosensitive resin layer thereon wherein said photosensitive resin layer is formed from a resin composition comprising a resin having rubber elasticity, an unsaturated monomer, a photopolymerization initiator and resin particles having an average particle size of about 0.01 to 6 micron, and when said photosensitive resin layer is cured, the cured layer has a JIS A hardness of 30.degree. to 80.degree. and an impact resilience of at least 20%.