Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/14—Inert intermediate or cover layers for charge-receiving layers
  • G03G5/147—Cover layers
  • G03G5/14708—Cover layers comprising organic material
  • G03G5/14713—Macromolecular material
  • G03G5/14791—Macromolecular compounds characterised by their structure, e.g. block polymers, reticulated polymers, or by their chemical properties, e.g. by molecular weight or acidity
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/14—Inert intermediate or cover layers for charge-receiving layers
  • G03G5/147—Cover layers
  • G03G5/14708—Cover layers comprising organic material
  • G03G5/14713—Macromolecular material
  • G03G5/14786—Macromolecular compounds characterised by specific side-chain substituents or end groups

Definitions

• This invention relates to an electrophotographic lithographic printing plate precursor and, more parti­cularly to a lithographic printing plate precursor having a photoconductive layer on which a surface layer having specific properties is provided.
• a number of offset printing plate precursors for directly producing printing plates have hitherto been proposed, and some of them have already been put into practical use. Widely employed among them is a system in which a photoreceptor, comprising a conductive support having provided thereon a photoconductive layer mainly comprising photoconductive particles (e.g., zinc oxide) and a resin binder, is subjected to an ordinary electrophotographic processing to form a highly lipo­philic toner image thereon. The surface of the photo­receptor is then treated with an oil-desensitizing solution called etching solution to selectively render non-image areas hydrophilic to obtain an offset printing plate.
• etching solution oil-desensitizing solution
• Requirements of offset printing plate precursors for obtaining satisfactory prints are such that an original should be reproduced faithfully on the photo­receptor; the surface of a photoreceptor should have affinity with an oil-desensitizing solution, so as to render non-image areas sufficiently hydrophilic and, at the same time, should have water resistance; and that a photoconductive layer having an image formed thereon is not released during printing and is well receptive to dampening water, so that the non-image areas hold the hydrophilic properties enough to be freed from stains even on printing a large number of prints.
• a photoconductive layer comprising particles of an organic photoconductive compound and a binder resin can be formed on a grained aluminum base.
• Printing plate precursors of this type can be produced by forming a toner image on a photo­ sensitive layer through the known electrophotographic processing such as described above and further removing the non-image areas by eluting with a processing solution, whereby the aluminum base corresponding to the non-image areas is exposed to form hydrophilic areas.
• the photosensitive layer using the organic photoconduc­tive compound comprises, for example, an oxadiazole compound or oxazole compound and an alkali-soluble binder resin (e.g., a styrene-maleic anhydride co­polymer, etc.), as disclosed in Japanese Patent Publication Nos. 17162/62 and 39405/71 and Japanese Patent Laid-Open Publication Nos. 2437/77 and 107246/81; or a phthalocyanine pigment or azo pigment and an alkali-soluble phenolic resin as disclosed in Japanese Patent Laid-Open Publication Nos. 105254/80, 16125/70, 150953/83, and 162961/83.
• an alkali-soluble binder resin e.g., a styrene-maleic anhydride co­polymer, etc.
• the surface layer becomes water-­soluble upon ring-opening, the surface layer is serious­ly inferior in water resistance even though the vinyl ether-maleic anhydride copolymer is combined with a compatible hydrophobic resin. Therefore, the printing durability of the resulting printing plate was about 500 to 600 prints at most.
• a surface layer capable of being rendered hydrophilic which comprises silylated polyvinyl alcohol as main component and a crosslinking agent as disclosed in Japanese Patent Laid-Open Publication Nos. 90343/85, 159756/85, and 217292/86.
• the surface layer can be rendered hydrophilic by hydrolysis of the silylated polyvinyl alcohol on the non-image areas.
• the degree of silylation of polyvinyl alcohol is controlled, and the remaining hydroxyl group is crosslinked by the crosslinking agent.
• hydrophilic polymer due to the limitations on the chemical structure of the hydrophilic polymer, it is difficult to exclude all adverse influences of the surface layer upon the functions of an electrophoto­graphic photoreceptor, such as charging properties, quality of a reproduced image (e.g., dot reproducibility and resolving power of image areas, resistance to background fog of nonimage areas, etc.), and light sensitivity.
• the former are those having functional groups capable of forming hydroxyl groups through decomposition as disclosed in Japanese Patent Application Nos. 8217/1988 and 90185/1988, those having functional groups capable of forming carboxyl groups through decomposition as disclosed in Japanese Patent Application Nos. 112607/1988 and 113458/1988 and those having functional groups capable of forming thiol groups, amino groups, phosphono groups or sulfo groups through decomposition as disclosed in Japanese Patent Application Nos. 134357/1988 and 135705/1988.
• These resins are those which form hydrophilic groups through hydrolysis or hydrogenolysis with an oil-­desensitizing solution or dampening water used during printing.
• a number of prints with clear image quality and without background stains can be obtained, since the hydrophilic property of non-image areas is further increased by the above described hydrophilic groups formed through decomposi­tion to make clear the lipophilic property of image areas and the hydrophilic property of non-image areas and to prevent the non-image areas from adhesion of a printing ink during printing, and a crosslinking structure is formed in the surface layer so that the resin rendered hydrophilic becomes water-insoluble, keeps water and swells through the crosslinking effect to give retention of water and to maintain the surface layer sufficiently hydrophilic.
• the carboxyl group or hydroxyl group previous­ly masked with a protective group is subjected to decomposition reaction with a processing solution to release the protective group.
• the resin of this type therefore, it is required, as important properties, that during storage, the resin is stably present without being hydrolyzed due to the humidity (moisture) in the air and during processing for rendering hydrophilic, the protective group removing reaction rapidly proceeds to form a hydrophilic group and the hydrophilic property of non-image areas can be improved.
• hydrophilic group-forming functional group which is stably present without decomposition even under severer conditions, e.g., during storage at a high temperature and high humidity for a long time, results in difficulty in a rapid decomposition with a processing solution and rapid feasibility of hydrophilic property.
• the present inventors have made studies in the field of electrophotographic lithographic printing plate precursors, with the aim of overcoming or reducing defects in the prior art, as noted above.
• the present invention provides an electrophotographic lithographic printing plate precursor utilizing an electrophotographic photoreceptor comprising a conductive support having provided thereon at least one photoconductive layer and further provided thereon a surface layer as an outermost layer, wherein said surface layer comprises, as a predominant component, at least one resin containing at least one polymeric component having a formyl group and/or functional group represented by the following General Formula (I): wherein R1 and R2 each represent, same or different, hydrocarbon groups or R1 and R2 are organic residual radicals which are combined with each other to form a ring.
• General Formula (I) wherein R1 and R2 each represent, same or different, hydrocarbon groups or R1 and R2 are organic residual radicals which are combined with each other to form a ring.
• the resin containing at least one polymeric component having the above described formyl group and/or functional group represented by General Formula (I) can previously be crosslinked and in this case, the resin has water proof property, which is preferable when realizing the hydro­philic property through reaction with a processing solution for rendering hydrophilic.
• the resin containing at least one polymeric component having the above described formyl group and/or functional group represented by General Formula (I) may be a resin further containing at least one functional group causing a hardening reaction by heat and/or light.
• Resin A in addition to the resin containing at least one polymeric component having formyl group and/or a functional group represented by General Formula (I), which will hereinafter be referred to as Resin A sometimes, at least one heat and/or light hardenable resin as Resin B is incorporated optionally with a crosslinking agent.
• Resin A in addition to the resin containing at least one polymeric component having formyl group and/or a functional group represented by General Formula (I), which will hereinafter be referred to as Resin A sometimes, at least one heat and/or light hardenable resin as Resin B is incorporated optionally with a crosslinking agent.
• the feature of the electrophotographic litho­graphic printing plate precursor having a priotoconduct­ive layer according to the present invention consists in that the resin in the surface layer as the outermost layer comprises Resin A containing at least one of formyl group and functional groups represented by General Formula (I) and optionally Resin B consisting of a heat and/or light hardenable resin, preferably being at least partly crosslinked, whereby when processing with a processing solution containing at least one hydrophilic compound with nucleophilic reactivity, the hydrophilic compound with nucleophilic reactivity is additionally reacted with the end of the formyl group or the functional group represented by General Formula (I) of Resin A and the surface layer can thus reveal hydrophilic property while simultaneously, it is rendered not or hardly soluble in water with maintaining the hydrophilic property because of the crosslinked structure in the resin.
• Resin A containing at least one of formyl group and functional groups represented by General Formula (I) and optionally Resin B consisting of a heat and/or light hard
• the lithographic printing plate precursor of the present invention has various advantages that an image faithful to an original can be reproduced without occurrence of background stains owing to the high hydro­philic property of non-image areas, the smoothness and electrostatic characteristics of the photoconductive layer are excellent and furthermore, the durability is improved.
• the lithographic printing plate precursor of the present invention is not sensitive to environmental influences during plate making, is very excellent in storage property before processing and is capable of undergoing rapidly a processing for rendering hydrophilic.
• the resin of the present invention or Resin A contains at least one copolymeric component containing at least one of formyl group and functional groups represented by General Formula (I): wherein R1 and R2 each represent, same or different, hydrocarbon groups or R1 and R2 each represent organic residual radicals which are connected with each other to form a ring.
• General Formula (I) wherein R1 and R2 each represent, same or different, hydrocarbon groups or R1 and R2 each represent organic residual radicals which are connected with each other to form a ring.
• R1 and R2 each represent hydrocarbon groups, they are preferably optionally substituted aliphatic groups containing 1 to 12 carbon atoms, for example, optionally substituted alkyl groups containing 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, decyl, dodecyl, methoxymethyl, ethoxymethyl, 2-hydroxyethyl, 2-chloro­ethyl, 2-bromoethyl, 1-fluoroethyl, 2-cyanoethyl, 2-­methoxyethyl, 2-ethoxyethyl, 3-hydroxypropyl, 3-methoxy­propyl groups, etc., optionally substituted alkenyl groups containing 2 to 12 carbon atoms, such as propenyl, butenyl, hexenyl, octenyl docenyl, dodeceny
• R1 and R2 represent organic residual groups which are connected with each other to form a ring, they are preferably functional groups representedby the following general formula (Ia), that is, cyclic acetal groups: wherein R3 and R4 each represent, same or different, hydrogen atoms, optionally substituted hydrocarbon groups containing 1 to 12 carbon atoms or -OR5 groups wherein R5 represents an optionally substituted hydrocarbon group containing 1 to 12 carbon atoms and n represents an integer of 1 to 4.
• general formula (Ia) that is, cyclic acetal groups: wherein R3 and R4 each represent, same or different, hydrogen atoms, optionally substituted hydrocarbon groups containing 1 to 12 carbon atoms or -OR5 groups wherein R5 represents an optionally substituted hydrocarbon group containing 1 to 12 carbon atoms and n represents an integer of 1 to 4.
• Preferred examples of the optionally substituted hydrocarbon groups containing 1 to 12 carbon atoms, as R3, R4 and R5, include aliphatic groups having the same contents as those defined in R1 and R2 and aromatic groups such as phenyl, tolyl, xylyl, methoxyphenyl, chlorophenyl, bromophenyl, methoxycarbonylphenyl, dimethoxyphenyl, chloromethylphenyl, naphthyl groups, etc.
• R1 to R5 are aliphatic groups, for example, alkyl groups of 1 to 6 carbon atoms, alkenyl groups of 3 to 6 carbon atoms and aralkyl groups of 7 to 9 carbon atoms, and n is an integer of 1 to 3.
• the surface layer resin of the present invention contains a polymeric component containing formyl group and/or a functional group represented by General Formula (I) and is modified from lipophilic to hydrophilic by processing with a processing solution containing a hydrophilic compound with nucleophilic reactivity.
• the mechanism of rendering hydrophilic is shown by the following reaction formula (I), for example, as to a case of using sulfite ion as the hydrophilic compound with nucleopriilic reactivity.
• p represents a resin part except the formyl group or functional group of General Formula (I).
• Resin A of the present invention has the feature that only when non-image areas as a lithographic printing plate precursor is subjected to oil-desensitization, it is reacted with a nucleophilic compound in a processing solution as described above, whereby the hydrophilic group is added to the end thereof and it is rendered hydrophilic. Since Resin A is not reactive with moisture in the air, there is no problem to be feared in storage of the lithographic printing plate precursor of the present invention. Since formyl group is a functional group which is very rapidly reactive with a nucleophilic compound, it is possible to rapidly render hydrophilic.
• the functional group represented by General Formula (I) is a precursor of formyl group and this precursor can readily be converted into formyl group through acid decomposition as shown by Reaction Formula (1). As well known in the art, this functional group is very excellent in storage stability.
• Examples of the copolymer constituent containing the formyl group and/or the functional group represented by General Formula (I) used in the present invention include those represented by the following repeating unit of General Formula (II): wherein Z represents -COO-, -OCO, -O-, -CO-, wherein R1 represents hydrogen atom or a hydro­carbon group, -CONHCOO-, -CONHCONH-, -CH2COO-, -CH2OCO- or Y represents a direct bond or organic radical for connecting -Z- and -W0, ( ⁇ Z-Y) ⁇ can direct­ ly connect and -W0, W0 represents the formyl group or the functional group represented by General Formula (I) and a1 and a2 may be same or different, each being hydrogen atom, a halogen atom, cyano group, an alkyl group or an aryl group.
• Z represents preferably -COO-, -OCO, -O-, -CO-, wherein R1 represents hydrogen atom, an optionally substituted alkyl group of 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, 2-­chloroethyl, 2-bromoethyl, 2-cyanoethyl, 2-methoxyethyl, 2-hydroxyethyl, 3-bromopropyl groups etc., an optionally substituted aralkyl group of 7 to 9 carbon atoms, such as benzyl, phenethyl, 3-phenylpropyl, chlorobenzyl, bromobenzyl, methylbenzyl, methoxybenzyl, chloromethyl­benzyl, dibromobenzyl groups, etc., an optionally substituted ary
• Y represents a direct bond or an organic radical for connecting -Z- and -W0.
• this radical is a carbon-carbon bond, between which hetero atoms (including oxygen, sulfur and nitrogen atom) may be present, which specific examples include individually or in combination of these groups, wherein r2, r3, r4, r5 and r6 have the meaning as the foregoing r1.
• a1 and a2 may be the same or different, each being a hydrogen atom, a halogen atom (e.g., chlorine, bromine), a cyano group, a hydrocarbon residue (e.g., an optically substituted alkyl group containing 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, hexyloxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, butoxycarbonylmethyl, etc., an aralkyl group such as benzyl, phenetyl, etc., and an aryl group such as phenyl, tolyl, xylyl, chlorophenyl, etc.
• a hydrocarbon residue e.g., an optically substituted alkyl group containing 1 to 12 carbon atoms, such as methyl, e
• linkage moiety ( ⁇ Z-Y) ⁇ in General Formula (II) may directly connect the moiety to the moiety -W0.
• Examples (a-1) to (a-15), a represents -H or -CH3.
• R6 and R7 each represent alkyl groups of 1 to 4 carbon atoms or -CH2C6H5
• R8 represents an alkyl group of C1 to C4, -CH2C6H5 or phenyl group.
• Resin A containing the polymeric component containing formyl group and/or the functional group represented by General Formula (I) as described above can be synthesized by any of known methods, for example, by a method comprising subjecting to polymerization reaction a monomer containing formyl group or the functional group represented by General Formula (I) and a polymerizable double bond group in the molecule (e.g. monomer corresponding to the recurring unit of General Formula (II)) and a method comprising reacting a low molecular compound containing formyl group or the functional group represented by General Formula (I) with a high molecular compound containing a polymeric constituent containing a functional group reactive with the low molecular compound, which is called "polymer reaction".
• Resin A containing formyl group can be synthesized by synthesizing the resin containing the functional group represented by General Formula (I) and then subjecting to an acid decomposition.
• the polymeric component containing formyl group and/or the functional group represented by General Formula (I) is generally in a proportion of 20 to 99% by weight, preferably 40 to 95% by weight based on the whole copolymer in a case where Resin A is of the copolymer.
• this resin has a molecular weight of 103 to 106, particularly, 3 ⁇ 103 to 5 ⁇ 105.
• Resin A of the present invention may be cross­linked, at least in part, in an electrophotographic lithographic printing plate precursor.
• a resin there can be used a previously crosslinked resin during coating a light-sensitive layer-forming material in the plate-making step or a resin containing crosslinking functional groups causing a hardenable reaction by heat and/or light, which can be crosslinked in a process for producing a lithographic printing plate precursor (e.g. during drying). These resins can be used in combina­tion.
• the solubility of the resin in distilled water at 20 to 25°C is preferably at most 90% by weight, more preferably at most 70% by weight.
• Introduction of a crosslinked structure in a polymer can be carried out by known methods, that is, a method comprising subjecting a monomer containing at least one of formyl group and the groups of General Formula (I) to polymerization reaction in the presence of a multifunctional monomer and a method comprising incorporating functional groups for effecting a crosslinking reaction in the polymer, then subjecting the polymer to polymer reaction with a compound containing formyl group or the group of General Formula (I) and effecting the crosslinking.
• a polar group such as -OH, -Cl, -Br, -I, -NH2, -COOH, -
• styrene derivatives such as divinyl benzene and trivinyl benzene
• esters of polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycols Nos.
• 1,3-butylene glycol 1,3-butylene glycol, neopentyl glycol, dipropylene glycol, poly­propylene glycol, trimethylolpropane, trimethylolethane, pentaerythritol and the like or polyhydroxyphenols such as hydroquinone, resorcinol, catechol and derivatives thereof with methacrylic acid, acrylic acid or crotonic acid, vinyl ethers and allyl ethers; vinyl esters of dibasic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, itaconic acid and the like, allyl esters, vinylamides and allylamides; and condensates of poly­amines such as ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine and the like with carboxylic acids containing vinyl groups such as methacrylic acid, acrylic acid, crot
• ester derivatives or amide derivatives contain­ing vinyl groups of carboxylic acids containing vinyl group, such as methacrylic acid, acrylic acid, meth­acryloylacetic acid, acryloylacetic acid, methacryloyl­propionic acid, acryloylpropionic acid, itaconyloyl­acetic acid and itaconyloylpropionic acid, reaction products of carboxylic anhydrides with alcohols or amines such as allyloxycarbonylpropionic acid, allyl­oxycarbonylacetic acid, 2-allyloxycarbonylbenzoic acid, allylaminocarbonylpropionic acid and the like, for example, vinyl methacrylate, vinyl acrylate, vinyl itaconate, allyl methacrylate, allyl acrylate, allyl itaconate, vinyl methacryloylacetate, vinyl methacryl­oylprop
• the monomer containing two or more polymerizable functional groups of the present invention is generally used in a proportion of at most 10mole%, preferably at most 5 mole% to all monomers, which is polymerized to form a previously crosslinked resin.
• the functional group can be any group capable of causing a chemical reaction among the molecules to form chemical linkages. That is, the reaction mode of forming link­ages among molecules by a condensation reaction or addition reaction, or crosslinkings by a polymerization reaction through heat and/or light can be utilized.
• the functional groups include at least one combination selected from the group A consisting of functional groups containing dissociable hydrogen atoms, for example, -COOH, -PO3H2, wherein R9 represents an aliphatic group, preferably optionally substituted linear or branched alkyl group containing 1 to 12 carbon atoms, such as methyl, ethyl, propyl, chloromethyl, dichloromethyl, trichloromethyl, trifluoromethyl, butyl, hexyl, octyl, decyl, hydroxyethyl or 3-chloropropyl group, or -OR9′ wherein R9′ has the same meaning as R9, -OH, -SH and -NH ⁇ R10 wherein R10 represents hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, such as methyl, ethyl, propyl or butyl group, and the group a consisting -NCO and -NCS and cyclic di
• Examples of the polymerizable double bond group include those of the foregoing polymerizable functional group.
• hardenable functional groups can be incorporated in one copolymeric constituent with formyl group or the functional groups represented by General Formula (I), or can be incorporated in another copolymeric constituent than a copolymeric constituent containing formyl group or the functional groups represented by General Formula (I).
• Examples of the monomer corresponding to the copolymer constituent containing these hardenable functional groups include vinyl compounds containing the functional groups copolymerizable with the polymeric constituents of General Formula (II).
• vinyl compounds include those described in, for example, Kobunshi Gakkai Edition "Polymer Data Handbook -Kisohen-", published by Baihukan, 1986, for example, acrylic acid, ⁇ and/or ⁇ -substituted acrylic acid such as ⁇ -acetoxy, ⁇ -acetoxymethyl, ⁇ -(2-amino­methyl), ⁇ -chloro, ⁇ -bromo, ⁇ -fluoro, ⁇ -tributylsilyl, ⁇ -cyano, ⁇ -chloro, ⁇ -bromo, ⁇ -chloro- ⁇ -methoxy and ⁇ , ⁇ -­dichloro substituted ones, methacrylic acid, itaconic acid, itaconic acid semi-esters, itaconic acid semi­amides, crotonic acid, 2-alkenylcarboxylic acids such as 2-pentenoic acid, 2-methyl-2-hexenoic acid, 2-octenoic acid, 4-methyl-2-hexenoic
• the content of "the copolymeric components containing the hardenable functional groups" is preferably 1 to 80% by weight, more preferably 5 to 50 % by weight based on the whole quantity of the surface layer resin.
• Resin A of the present invention contains functional groups capable of undergoing a crosslinking reaction with Resin B by heating or irradiating.
• these functional groups there can be used those similar to the following crosslinking functional groups contained in Resin B (heat and/or light-hardenable functional groups: sometimes referred to as hardenable functional groups).
• the content of copolymeric constituents containing the hardenable functional groups is preferably 1 to 20% by weight, more preferably 3 to 10% by weight in Resin A.
• incorporation of at least one functional group selected from the group consisting of the hardenable functional groups in Resin A is carried out by a method comprising introducing a low molecular, hardenable functional group-containing compound into a polymer containing formyl group and/or functional groups represented by General Formula (I) by polymer reaction, or a method comprising copolymerizing at least one monomer corresponding to the copolymeric component containing at least one of the hardenable functional groups with a monomer corresponding to the repeating unit represented by General Formula (II) (monomer synthesis).
• the former polymer reaction can be carried out by any of known methods, for example, Nippon Kagakukai Edition, Shin-Jikken Kagakukoza, Vol. 14, "Synthesis and Reaction of Organic Compounds (I) to (V) (Yuki Kagobutsu no Gosei to Hanno)" published by Maurzen KK, 1978, and Yoshio Iwakura and Keisuke Kurita “Reactive Polymers (Hannosei Kobunshi)” published by Kohdansha (1977).
• vinyl compounds containing the crosslinking functional groups which are copolymerizable with the polymeric component containing the hydrophilic group-­forming functional group in Resin A (e.g. compound corresponding to General Formula (II)), such as those exemplified above as the monomer corresponding to the copolymeric component containing the crosslinking functional groups.
• Resin B used in the present invention will now bi illustrated in detail.
• Resin B is a hardenable resin causing a crosslinking reaction by heat and/or light, preferably causing a crosslinking reaction with the functional group described above in Resin A, and includes any of resins containing "heat and/or light-­hardenable functional groups (sometimes referred to as hardenable functional groups in brief)" which will hereinafter be illustrated. As illustrated above, these hardenable functional groups may be contained in Resin A.
• the light-hardenable functional group of the hardenable functional groups of the present invention there can be used functional groups used in light-­sensitive resins of the prior art as light-hardenable resins, for example, describe in Hideo Inui and Gentaro Nagamatsu "Light-sensitive Polymers (Kankosei Kobunshi)" Kodansha KK, 1977, Takahiro Tsunoda "New Light-sensitive Resins (Shin-kankosei Jushi)” published by Insatsu Gakkai Shuppanbu, 1981, G.E. Green and B.P. Strark “J. Macro. Sci. Reas. Macro. Chem.” C 21 (2), 187-273 (1981-­82) and C.G. Rattey "Photopolymerization of Surface Coatings” published by A. Wiley Interscience Pub., 1982).
• heat-hardenable functional group of the hardenable functional groups of the present invention there can be used functional groups, for example, cited in the literatures described above to exemplify the polymerizable double bond groups.
• R9 represents a hydrocarbon group, e.g., optionally substituted alkyl group containing 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, 2-chloroethyl, 2-methoxyethyl, 2-cyanoethyl, etc., optionally substituted cycloalkyl group containing 4 to 8 carbon atoms, such as cycloheptyl, cyclohexyl, etc., optionally substituted aralkyl group containing 7 to 12 carbon atoms, such as benzyl, phenethyl, 3-phenyl­propyl, chlorobenzyl, methylbenzyl, methoxybenzyl group, etc., and optional
• Group B capable of bonding with the functional group having dissociable hydrogen
• R10 represents hydrogen atom or an alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, octyl group, etc.
• a3 and a4 each represent hydrogen atoms, halogen atoms such as chlorine, bromine atom, etc., or alkyl groups containing 1 to 4 carbon atoms, such as methyl, ethyl group, etc.
• a crosslinked structure can be formed by chemical bonding of the functional groups, Groups A and B, for example, selected so as to combine at least one member respectively selected from Groups A and B shown in the following Table 1:
• the crosslinking reaction can be carried out by a polymerizable reaction using polymerizable double bond groups, exemplified above as the polymerizable function­al groups.
• the monomer containing "the heat and/or light hadenable functional group” there can be used any of monomers containing hardenable functional groups in the substituents, which are copolymerizable with the monomer corresponding to the foregoing "polymeric component represented by General Formula (II)".
• copolymeric component containing the "heat and/or light-hardenable functional group” are the following repeating units (b-1) to (b-26):
• (meth)acrylic copolymers containing at least 30% by weight, based on the total amount of the copolymer, of a monomer repre­sented by the following General Formula (III) as a co­polymeric constituent, exemplified as Resin B: wherein U is hydrogen atom, a halogen atom such as chlorine or bromine atom, cyano group, an alkyl group containing 1 to 4 carbon atoms, and R16 is an alkyl group containing 1 to 18 carbon atoms, which can be substi­tuted, such as methyl, ethyl, propyl, butgyl, pentyl, hexyl, octyl, decyl, dodecyl, tridecyl, tetradecyl, 2-­methoxyethyl or 2-ethoxyethyl group, an alkenyl group containing 2 to 18 carbon atoms, which can be substi­t
• the content of "copolymeric components containing crosslinking (hardenable) functional groups” is preferably 0.5 to 40 wt%.
• the weight average molecular weight of Resin B is preferably 1x103 to 1x105, more preferably 5x103 to 5x104.
• the ratio of Resin A and Resin B, used in the present invention, depending on the kind, grain diameter and surface state of inorganic photoconductive materials used therewith, is generally 40-99 of the former 1-60 of the latter (by weight), preferably 60-95 to 5-40.
• the surface layer resin of the present invention may further contain a crosslinking agent in addition to Resin A, or Resin A + Resin B.
• a crosslinking agent in addition to Resin A, or Resin A + Resin B.
• a reaction promoter so as to promote the crosslinking reaction, for example, acids such as acetic acid, propionic acid, butyric acid, benzene­sulfonic acid, p-toluenesulfonic acid, etc., peroxides, azobis compounds, crosslinking agents, sensitizers, photopolymerizable monomers and the like.
• crosslinking agent in the present invention there can be used compounds commonly used as crosslinking agents, for example, described in Shinzo Yamashita and Tosuke Kaneko "Handbook of Crosslinking Agents (Kakyozai Handbook)” published by Taiseisha (1981) and Kobunshi Gakkai Edition "High Molecular Data Handbook -Basis- (Kobunshi Data Handbook -Kisohen-)” published by Baihunkan (1986).
• crosslinking agent examples include organo­silane compounds such as vinyltrimethoxysilane, vinyl­tributoxysilane, ⁇ -glycidoxypropyltrimethoxysilane, ⁇ -­mercaptopropyltriethoxysilane, ⁇ -aminopropyltriethoxy­silane and other silane coupling agents; polyisocyanate compounds such as tolylene diisocyanate, o-tolylene diisocyanate, diphenylmethane diisocyanate, triphenyl­methane triisocyanate, polymethylenepolyphenyl iso­cyanate, hexamethylene diisocyanate, isophorone diiso­cyanate, high molecular polyisocyanates; polyol compounds such as 1,4-butanediol, polyoxypropylene glycol, polyoxyalkylene glycol, 1,1,1-trimethylolpropane and the like; polyamine compounds such as ethylene­di
• the quantity of the crosslinking agent used in the present invention is generally 0.5 to 30% by weight, preferably 1 to 10% by weight based on the resin used in the surface layer.
• the crosslinking reaction is carried out by a reaction system for forming chemical bonds among functional groups
• organic acids such as acetic acid, propionic acid, butyric acid, benzenesulfonic acid and p-toluenesulfonic acid are used as the promoter
• polymerization initia­tors such as peroxides and azobis compounds, the latter being preferable
• multifunctional polymerizable group-containing monomers such as vinyl methacrylate, allyl methcrylate, ethylene glycol diacrylate, poly­ethylene glycol diacrylate, divinyl succinate, divinyl adipate, diallyl succinate, 2-methylvinyl methacrylate, divinylbenzene and the like.
• Resins A and B of the present invention other resins can jointly be used in addition to Resins A and B of the present invention, for example, alkyd resins, poly­butylal resins, polyolefin resins, ethylene-vinyl acetate resins, styrene resins, styrene-butadiene resins, acrylate-burtadiene resins, vinyl alkanate resins, polyester resins, acrylic resins and the like.
• these resins are described in Takaharu Kurita and Jiro Ishiwataru "High Molecular Materials (Kobunshi)" 17 , 278 (1968) and Harumi Miyamoto and Hidehiko Takei "Imaging” No. 8, page 9 (1973).
• the resin of the present invention and the known resin can be mixed in optional proportions, but it is preferable to adjust the mixing proportion so that the content of the hydrophilic group-forming functional group-containing resin be 20 to 99% by weight, preferably 40 to 95% by weight based on the whole resin, since if less than 20% by weight, the resulting lithographic printing plate precursor meets with a problem that the hydrophilic property obtained by the oil-desensitization treatment with an oil-desensitizing solution or dampening water to result in background stains during printing, while if more than 99% by weight, the image-forming property during reproducing is not good and the film strength of the photoconductive layer during printing is lowered, resulting in deterioration of the durability.
• the surface layer resin of the present invention is subjected to crosslinking after coating a surface layer forming composition.
• the crosslinking is preferably carried out, for example, by maintaining the drying conditions at a high temperature and/or for a long period of time, or by further subjecting to a heat treatment after drying the coating solvent, for example, at 60 to 120°C for 5 to 120 minutes.
• the crosslinking is carried out after coating by irradiating electron ray, X-rays, ultraviolet rays or plasma during, before or after drying and the reaction can further be promoted by the above described heating treatment during or after drying. Joint use of the above described reaction promoter results in that this treatment can be carried out under milder conditions.
• Resin A of the surface layer of the present invention has such an action that hydrophilic groups appear by an oil-desensitizing treatment to render non-­image areas more hydrophilic.
• the surface layer resin having a crosslinked structure at least in a part of the polymer is capable of preventing the hydrophilic group-containing resin formed by an oil-desensitization processing from being water-soluble and dissolved out of the non-image area, while maintaining the hydrophilic property.
• the hydrophilic property of a non-image area can further be enhanced by hydrophilic groups formed in the resin, such as sulfo, phosphono, carboxyl and hydroxyl groups, and the durability is improved. Even if printing conditions become severer, for example, a printing machine is large-sized or printing pressure is fluctuated, a large number of prints with a clear image quality and free from backgroun stains can be obtained.
• ferro­cyanide compounds are used as a predominant agent in an oil-desensitizing solution for oil-desensitizing zinc oxide, which compounds need a special control of handl­ing from the standpoint of preventing the environmental pollution, and the kinds of available color inks are limited or it is difficult to use a neutral paper as a printing paper, because an oil-desensitizing agent is ordinarily added to the dampening water during printing so as to make up for the oil-desensitized hydrophilic material physically adhered to the surface layer of a printing plate precursor and consumed after printing a number of prints.
• inorganic compounds and organic compounds can be used as the photoconductive compound.
• the inorganic photoconductive compound examples include zinc oxide, titanium oxide, zinc sulfide, cadmium sulfide, selenium, selenium alloys such as selenium-tellurium, lead sulfide and the like, well known in the art. From the standpoint of the environ­mental pollution, zinc oxide or titanium oxide is preferable.
• a binder resin as described above, is generally used in a proportion of 10 to 60 parts by weight, preferably 15 to 40 parts by weight to 100 parts by weight of the inorganic photoconductive compound.
• the organic compound there can be used any of known compounds, specifically the following two kinds of compounds known as for an electrophotographic lithographic printing plate pre­cursor.
• the first class has a photoconductive layer comprising an organic photoconductive compound, sensi­tizing dye and binder resin, as predominant components, as disclosed in Japanese Patent Publication Nos. 17162/­1962 and 51462/1987, and Japanese Patent Laid-Open Publication Nos. 2437/1977, 19802/1979, 107246/1981 and 161863/1982 and the second class has a photoconductive layer comprising a charge generating agent, charge transporting agent and binder resin, as predominant components, as disclosed in Japanese Patent Laid-Open Publication Nos.
• a photoconductive layer of two-layer structure comprising a charge generating agent and a charge transporting agent respectively in separate layers
• the electrophotographic lithographic printing plate precursor of the present invention can be in any form of the above described two kinds of photo­conductive layers.
• the organic photoconductive compound of the present invention functions as a charge transporting agent.
• organic photoconductive compound used in the present invention examples are as follows:
• the organic photo­conductive compounds are not limited to those exempli­fied in (a) to (t), but all other organic photoconduc­tive compounds known in the art can be used. These organic photoconductive compounds can be used either alone or in combination of two or more thereof.
• sensitizing dye contained in the photo­conductive layer there can be used the commonly used sensitizing dyes for electrophoto­graphic photoreceptors described in "Denshi Shashin (Electrophotography)” 12 9 (1973), and “Yuki Gosei Kagaku (Organic Synthetic Chemistry)” 24 (11), 1010 (1966).
• sensitizing dyes for electrophoto­graphic photoreceptors described in "Denshi Shashin (Electrophotography)” 12 9 (1973), and “Yuki Gosei Kagaku (Organic Synthetic Chemistry)” 24 (11), 1010 (1966).
• pyrylium dyes as described in US Patent Nos. 3,141,770 and 4,283,475, Japanese Patent Publication No. 25658/1973 and Japanese Patent Laid-Open Publication No. 71965/1987, triaryl­methane dyes as described in "Applied Optics Supplement” 3 , 50 (1969) and Japanese Patent Laid-Open Publication No.
• the charge generating agent contained in the photoconductive layer of the second example there can be used the commonly used various organic and inorganic charge generating agents, for example, selenium, selenium-tellurium, cadmium sulfide, zinc oxide and organic pigments described below (1) to (9):
• These pigments can be used either alone or in combination of two or more thereof.
• the mixing ratio of the organic photoconductive compound and binder resin i.e. the upper limit of the content of the organic photoconductive compound is determined by the compatibility of the organic photo­conductive compound and binder resin and addition of the organic photoconductive compound in an amount exceeding the upper limit results in crystallization thereof, which should be avoided. Since the electrophotographic sensitivity is lowered with the decrease of the content of the organic photoconductive compound, it is preferivelyable to incorporate the organic photoconductive compound as much as possible in such a range that crystallization of the organic photoconductive compound does not take place.
• the content of the organic photoconductive compound is generally 5 to 120 parts by weight, preferivelyably 10 to 100 parts by weight per 100 parts by weight of the binder resin.
• various coloring matters or dyes can be used as a spectro sensitizer, illustrative of which are carbonium dyes, diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, phthalein dyes, polymethine dyes such as oxonol dyes, merocyanine dyes, cyanine dyes, rhodacyanine dyes, styryl dyes, etc. and phthalocyanine dyes which can contain metals, as described in Harumi Miyamoto and Hidehiko Takei "Imaging" No. 8, page 12 (1973), C.Y. Young et al.
• polymethine dyes such as oxonol dyes, merocyanine dyes, cyanine dyes and rhodacyanine dyes
• polymethine dyes such as oxonol dyes, merocyanine dyes, cyanine dyes and rhodacyanine dyes
• polymethine dyes capable of spectrally sensitizing near infrared radiations to infrared radiations with longer wavelengths of at least 700 nm are described in Japanese Patent Publication No. 41061/1976; Japanese Patent Laid-Open Publication Nos. 840/1972, 44180/1972, 5034/1974, 45122/1974, 46245/1982, 35141/1981, 157254/1982, 26044/1986 and 27551/1986; U.S. Patent Nos. 3,619,154 and 4,175,956; and "Research Disclosure" 216, pages 117-118 (1982).
• the photoconductive layer of the electro­photographic lithographic printing plate precursor of the present invention can be incorporated various known additives which have hitherto been used for electro­photographic photoreceptors.
• additives include chemical sensitizers to improve the electrophotographic sensitivity, various plasticizers to improve the film property, surfactants, etc.
• Examples of the chemical sensitizer are electron accepting compounds such as p-­benzoquinone, chloranil, fluoranil, bromanil, dinitro­benzene, anthraquinone, 2,5-dichlorobenzoquinone, nitro­phenol, tetrachlorophthalic anhydride, 2,3-dichloro-5,6-­dicyanobenzoquinone, dinitrofluoroenone, tetracyanoethyl­ene and the like, and compounds as described in Japanese Patent Laid-Open Publication Nos. 65439/1983, 102239/­1983, 129439/1983 and 71965/1987.
• plasticizer for example, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, triphenyl phosphate, diisobutyl adipate, dimethyl sebacate, dibutyl sebacate, butyl laurate, methyl phthalyl ethyl glycolate, dimethylglycol phthalate, etc. can be added so as to improve the flexibility of the photoconductive layer in such a range that the static characteristics of the photoconductive layer are not deteriorated.
• the quantity of the various additives is not particularly limited, but is generally in the range of 0.001 to 2.0 parts by weight per 100 parts by weight of the photoconductor.
• the thickness of the photoconductive layer is generally 1 to 100 ⁇ m, preferably 10 to 50 ⁇ m.
• the thickness of the charge generating layer is generally 0.01 to 1 ⁇ m, preferably 0.05 to 0.5 ⁇ m.
• the photoconductive layer of the present invention can be provided on a support as well known in the art.
• a support for an electrophoto­graphic light-sensitive layer is preferably electro­conductive and as the electroconductive support, there can be used, as known in the art, substrates such as metals, papers, plastic sheets, etc.
• the surface layer capable of being rendered hydrophilic according to the present invention has a thickness of 10 ⁇ m or less, and preferably from 0.1 to 5 ⁇ m particularly for use in Carlson's processing. Thick­ness of the surface layer more than 10 ⁇ m would result in disadvantages, such as reduced sensitivity and increased residual potential of the resulting electro­photographic photoreceptor.
• the lithographic printing plate precursor according to the present invention can be generally produced as follows.
• An electrophotographic photo­sensitive layer (photoconductive layer) is first formed on a conductive support in a usual manner.
• a coating composition prepared by dissolving or dispersing the resin of the invention and, if desired, various additives as described above in a volatile hydrocarbon solvent having a boiling point of 200°C or lower is then coated on the photoconductive layer, followed by drying to form a surface layer.
• the hydrocarbon solvent to be used preferably includes halogenated hydrocarbon containing 1 to 3 carbon atoms, e.g., dichloromethane, chloroform, 1,2-dichloroethane, tetrachloroethane, dichloropropane, trichloroethane, etc.
• solvents commonly employed for coating composi­tions such as aromatic hydrocarbons, e.g., chloro­benzene, toluene, xylene, benzene, etc.; ketones, e.g., acetone, 2-butanone, etc.; ethers, e.g., tetrahydro­furan, etc.; methylene chloride; and mixtures thereof, can also be used.
• aromatic hydrocarbons e.g., chloro­benzene, toluene, xylene, benzene, etc.
• ketones e.g., acetone, 2-butanone, etc.
• ethers e.g., tetrahydro­furan, etc.
• methylene chloride e.g., methylene chloride
• Production of a lithographic printing plate using the electrophotographic lithographic printing plate precursor of the present invention can be carried out in known manner by forming a copying image thereon and then subjecting the non-image area to an oil-­desensitization processing according to the present invention.
• the oil-desensitization (i.e. giving hydrophilic property) of the resin of the present invention, containing the formyl group can be acccom­plished by processing with a solution containing a compound having hydrophilic groups capable of readily undergoing nucleophilic reaction with the double bonds in water or a water-soluble organic solvent.
• the hydrophilic compound causing a nucleophilic substitution reaction with the formyl group includes a hydrophilic compound containing a substituent having a nucleophilic constant n of at least 5.5 (Cf. R.G. Pearson, H. Sobel and J. Songstad "J. Amer. Chem.
• Examples of the mercapto compound are 2-­mercaptoethanol, 2-mercaptoethylamine, N-methyl-2-­mercaptoethylamine, N-(2-hydroxyethyl)-2-mercapto­ethylamine, thioglycolic acid, thiomalic acid, thio­salicyclic acid, mercaptobenzenedicarboxylic acid, 2-­mercaptoethanesulfonic acid, 2-mercaptoethylphosphonic acid, mercaptobenzenesulfonic acid, 2-mercaptopropion­ylaminoacetic acid, 2-mercapto-1-aminoacetic acid, 1-­mercaptopropionylaminoacetic acid, 1,2-dimercapto­propionylaminoacetic acid, 2,3-dihydroxypropylmercaptan, 2-methyl-2-mercapto-1-aminoacetic acid and the like.
• sulfinic acid examples include 2-hydroxy­ethylsulfinic acid, 3-hydroxypropanesulfinic acid, 4-­hydroxybutanesulfinic acid, carboxybenzenesulfinic acid, dicarboxybenzenesulfinic acid and the like.
• hydrazide compound examples include 2-­hydrazinoethanesulfonic acid, 4-hydrazinobutanesulfonic acid, hydrazinobenzenesulfonic acid, hydrazinobenzene­disulfonic acid, hydrazinobenzoic acid, hydrazino­benzenedicarboxylic acid and the like.
• Examples of the primary or secondary amine compound are N-(2-hydroxyethyl)amine, N,N-di(2-hydroxy­ethyl)amine, N,N-di(2-hydroxyethyl)ethylenediamine, tri­(2-hydroxyethyl)ethylenediamine, N-(2,3-dihydroxy­propyl)amine, N,N-di(2,3-dihydroxypropyl)amine, 2-amino­ propionic acid, aminobenzoic acid, aminopyridine, amino­benzenedicarboxylic acid, 2-hydroxyethylmorpholine, 2-­carboxyethylmorpholine, 3-carboxypiperidine and the like.
• the nucleophilic compounds are used in such a manner that each of them is contained in the foregoing oil-desensitization processing solution of a photo­conductor or in the foregoing processing solution of the binder resin.
• the quantity of the nucleophilic compound in such a processing solution is generally 0,1 to 10 mol/l, preferably 0.5 to 5 mol/l.
• the processing solution has preferably a pH of at least 4.
• the processing condi­tions are a temperature of 15 to 60°C and an immersing period of time of 10 seconds to 5 minutes.
• the processing solution may contain other compounds, for example, water-soluble organic solvents, individually or in combination, in a proportion of 1 to 50 parts by weight to 100 parts by weight of water, examples of which are alcohols such as methanol, ethanol, propanol, propargyl alcohol, benzyl alcohol, phenethyl alcohol, etc., ketones such as acetone, methyl ethyl ketone, aceto­phenone, etc., ethers such as dioxane, trioxane tetra­ hydrofuran, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, tetrahydropyran, etc., amides such dimethyl­formamide, dimethylacetamide, etc., esters such as methyl acetate, ethyl acetate, ethyl formate, etc.
• alcohols such as methanol, ethanol, propanol, propargyl alcohol, benz
• a surfactant can be incorporated in the processing solution in a proportion of 0.1 to 20 parts by weight to 100 parts by weight of water, illustivelyrative of which are anionic, cationic and nonionic surfactants well known in the art, for example, described in Hiroshi Horiguchi "New Surfactants (Shin-­Kaimen Kasseizai)" published by Sankyo Shuppan KK, 1975, Ryohei Oda and Kazuhiro Teramura “Synthesize of Surfactants and Applications Thereof (Kaimen Kasseizai no Gosei to sono Oyo)” published by Maki Shoten, 1980.
• the oil-desensitization of the resin of the present invention is characterized in that it is rendered hydrophilic by carrying out the alcohol removing reaction through acid decomposition as shown in the foregoing Reaction Formula (1) and then subjecting the resulting formyl group to nucleophilic reaction with a nucleophilic reagent.
• the thus resulting polymer A-1 had a weight average molecular weight ( M w) of 4.3x104.
• a mixedd solution of 90 g of a monomer (M-2) having the following structure, 10 g of 2-hydroxyethyl methacrylate and 200 g of toluene was heated at a temperature of 70°C under a nitrogen stream. While stirring, 1.5 g of A.I.B.N. was added thereto, followed by reacting for 5 hours, and 0.5 g of A.I.B.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-2 had a weight average molecular weight ( M w) of 3.5x104.
• a mixed solution of 92 g of a monomer M-3 having the following structure, 8 g of 2,4-dihydroxypropyl methacrylate and 200 g of toluene was heated at a temperature of 75°C under a nitrogen stream. While stirring, 1.0 g of A.I.B.N. was added thereto, followed by reacting for 4 hours and 0.4 g of A.I.B.N. was further added, followed by reacting for 3 hours, thus obtaining the polymer A-3 with an M w of 5.0x104.
• a mixed solution of 18 g of ethyl methacrylate, 80 g of a monomer M-4 having the following structure, 2.0 g of divinylbenzene and 200 g of toluene was heated at a temperature of 70°C under a nitrogen stream. While stirring, 1.5 g of azobis(isovaleronitrile) (hereinafter referred to as A.B.V.N.) was added thereto, followed by reacting for 4 hours and 0.5 g of A.B.V.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-5 had an ( M w) of 1.5x105.
• a mixed solution of 85 g of the monomer M-4, 10 g of 2-hydroxyethyl methacrylate, 5 g of acrylic acid and 200 g of toluene was heated at a temperature of 90°C under a nitrogen stream, to which 6 g of A.I.B.N. was added, followed by reacting for 4 hours.
• the thus resulting polymer A-6 had an ( M w) of 8.5x103.
• a mixed solution of 78 g of a monomer M-5 having the following structure, 20 g of allyl methacrylate, 2 g of 2-(2-carboxyethylcarbonyloxy)ethyl methacrylate and 300 g of toluene was heated at a temperature of 60°C under a nitrogen stream, to which 1.5 g of A.B.V.N. was added, followed by reacting for 4 hours and 0.5 g of A.B.V.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-7 had an ( M w) of 6.8x104.
• a mixed solution of 95 g of the monomer M-5, 5 g of methacrylic acid, 3 g of divinylbenzene, 1.5 g of n-­dodecyl mercaptan and 200 g of toluene was heated at 75°C under a nitrogen stream. 1 g of A.I.B.N. was added thereto, followed by reacting for 4 hours, 0.5 g of A.I.B.N. was further added, followed by reacting for 3 hours and 0.5 g of A.I.B.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-8 had an ( M w) of 7.3x103.
• a mixed solution of 63.5 g of benzyl methacryl­ate, 35 g of the monomer (M-1), 1.5 g of acrylic acid and 200 g of toluene was heated at a temperature of 75°C under a nitrogen stream. While stirring, 1.0 g of A.I.B.N. was added thereto, followed by reacting for 4 hours, and 0.4 g of A.I.B.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-­10 had a weight average molecular weight ( M w) of 4.3x104.
• a mixed solution of 52 g of phenyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, 30 g of a monomer M-6 having the following structure, 2.0 g of acrylic acid and 200 g of toluene was heated at a temperature of 70°C under a nitrogen stream. While stirring, 1.5 g of A.I.B.N. was added thereto, followed by reacting for 5 hours and 0.5 g of A.I.B.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-­11 had a ( M w) of 3.5x104.
• a mixed solution of 64.5 g of 2-chlorophenyl methacrylate, 34 g of the monomer M-3, 1.5 g of meth­acrylic acid and 200 g of toluene was heated at a temperature of 75°C under a nitrogen stream. While stirring, 1.0 g of A.I.B.N. was added thereto, followed by reacting for 4 hours and 0.4 g of A.I.B.N. was further added, followed by reacting for 3 hours. After cooling to room temperature, 10 g of an ethanol solution of 10 weight % of HCl was added to the resulting reaction mixture and stirred at room temperature for 1 hour, followed by reprecipitating in 2000 ml of methan­ol. The precipitated white crystals was collected by filtering and dried under reduced pressure at room temperature, thus obtaining the polymer A-12 with a yield of 75 g and an ( M w) of 4.5x104.
• a mixed solution of 18 g of ethyl methacrylate, 80 g of a monomer M-7 having the following structure, 2.0 g of divinylbenzene and 200 g of toluene was heated at a temperature of 70°C under a nitrogen stream. While stirring, 1.5 g of A.B.V.N. was added thereto, followed by reacting for 4 hours and 0.5 g of A.B.V.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-13 had an ( M w) of 1.5x105.
• a mixed solution of 85 g of the monomer M-7, 10 g of 2-hydroxyethyl methacrylate, 5 g of acrylic acid and 200 g of toluene was heated at a temperature of 90°C under a nitrogen stream, to which 6 g of A.I.B.N. was added, followed by reacting for 4 hours.
• the thus resulting polymer A-14 had an ( M w) of 8.5x103.
• a mixed solution of 78 g of a monomer M-8 having the following structure, 20 g of allyl methacrylate, 2 g of 2-(2-carboxyethylcarbonyloxy)ethyl methacrylate and 300 g of toluene was heated at a temperature of 60°C under a nitrogen stream, to which 1.5 g of A.B.V.N. was added, followed by reacting for 4 hours and 0.5 g of A.B.V.N. was further added, followed by reacting for 3 hours.
• the thus resulting polymer A-15 had an ( M w) of 6.8x104.
• a mixed solution of 95 g of the monomer M-8, 5 g of methacrylic acid, 3 g of divinylbenzene, 1.5 g of n-­dodecyl mercaptan and 200 g of toluene was heated at 75°C under a nitrogen stream. 1 g of A.I.B.N. was added thereto, followed by reacting for 4 hours, 0.5 g of A.I.B.N. was further added, followed by reacting for 3 hours and 0.5 g of A.I.B.N. was further added, followed by reacting for 3 hours. After cooling, 20 g of tri­ethylamine was added and stirred at a temperature of 30°C for 1 hour.
• Synthetic Example 15 of Resin A was repeated except changing the copolymeric components as shown in Table 2 to synthesize copolymers having the following structures as shown in Table 2.
• the resulting polymers A-17 to A-25 each had an ( M w) of 4x104 to 6x104.
• the photosensitive composition was coated on a transparent conductive support (a 100 ⁇ m thick poly­ethylene terephthalate base having deposited thereon indium oxide; surface resistivity: 103 ⁇ ) by means of a wire round rod to form a photosensitive layer having a thickness of about 4 ⁇ m.
• a solution of 5% by weight (as solid content) of Resin A-2 and 0.5% by weight of 1,3-xylylene diisocyan­ate in toluene was coated onto the surface of this electrophotographic photoreceptor by a doctor blade and heated at 110°C for 2 hours to form a surface layer having a thickness of about 2 ⁇ m.
• the resulting photosensitive material was subjected to oil-desensitization by immersing for 30 seconds in an oil-desensitizing solution (E-1) prepared by the following recipe: Oil-desensitizing Processing Solution (E-1) Sodium Sulfite 52 g Newcol B 4S N (made by Nippon Nyukazai KK) 10 g Methyl Ethyl Ketone 100 g Distilled Water to 1000 ml
• the above-prepared lithographic printing plate precursor was processed by an automatic printing plate making machine ("'ELP 404V” manufactured by Fuji Photo Film Co., Ltd.) using a negatively chargeable liquid developer to form a toner image thereon.
• the precursor was then subjected to oil-desensitization under the same conditions as described above.
• the resulting printing plate (offset master plate) was mounted on an offset printing machine ("Hamada Star 800SX” manufactured by Hamada Star K.K.), and printing on fine paper was carried out.
• the number of prints that could be obtained with no problem of image quality and background stain formation on the non-image areas was 10,000.
• a solution containing 5% by weight (as solid content) of Resin A-4 and 0.6% by weight of 1,6-hexane diisocyanate in toluene was coated on the resulting photoreceptor by a doctor blade to form a surface layer with a thickness of about 2 ⁇ m on the photosensitive layer.
• a paper analyzer Paper Analyzer SP-428 - commercial name- manufactured by Kawaguchi Denki KK
• the light-sensitive material was processed by an automatic plate making machine (ELP 404V -commercial name- manufactured by Fuji Photo Film Co., Ltd.) using a toner (ELP-T -commercial name- manufac­ tured by Fuji Photo Film Co., Ltd.) in the same manner as in Example 1.
• the resulting master plate for offset printing had a clear image having a density of at least 1.0.
• the plate was subjected to oil-desensiti­zation by immersing for 30 seconds in an oil-desensi­tizing solution (E-2) prepared by the following recipe, followed by washing with water: Oil-desensitizing Processing Solution (E-2) Thiosalicylic Acid 55 g Benzyl Alcohol 100 g These components were dissolved in distilled water to 1000 ml and the pH of the solution was adjusted to 12.0 with sodium hydroxide. The non-image area was sufficiently rendered hydrophilic as represented by a contact angle with distilled water of less than 10°.
• the print obtaining 10000 prints had a clear image and no fog on the non-image area.
• the light-sensitive material was subjected to corona discharge at -6kV for 20 seconds in a dark room at a temperature of 20°C and relative humidity of 65% using a paper analyzer (Paper Analyzer SP-428 -commercial name- manufacture by Kawaguchi Denki KK) and then allowed to stand for 10 seconds, at which the surface potential V10 was measured. Then, the sample was further allowed to stand in the dark room as it was for seconds to measure the surface potential V70, thus obtaining the retention of potential after the dark decay for 60 seconds, i.e., dark decay retention ratio (DRR (%)) represented by (V70/V10)x100 (%).
• DRR dark decay retention ratio
• the surface of the photoconductive layer was negatively charged to -400 V by corona discharge, then irradiated with a visible ray of an intensity of 2.0 lux and the time required for dark decay of the surface potential (V10) to 1/10 was measured to evaluate an exposure quantity E 1/10 (lux ⁇ sec).
• a mixture of 45 g of a copolymer of methyl methacrylate, ethyl methacrylate and acrylic acid (39/60/1 weight ratio) having a weight average molecular weight of 42000, 200 g of zinc oxide, 0.03 g of Rose Bengal, 0.02 g of tetrabromophenol, 0.20 g of phthalic anhydride and 300 g of toluene was dispersed in a ball mill for 2 hours to prepare a light-sensitive layer-­forming composition, which was then applied to a paper rendered electrically conductive to give a dry coverage of 25 g/m2 by a wire bar coater, followed by drying at 100°C for 1 minute.
• a solution containing 5% by weight of Resin A-6 and 0.75% by weight of 1,4-xylylene diisocyanate in toluene was coated on the resulting photoreceptor by a doctor blade and heated at 90°C for 2 hours to form a surface layer with a thickness of about 2 ⁇ m on the light-sensitive layer.
• the thus coated paper was allowed to stand in a dark place at 20°C and 65% RH for 24 hours to prepare electrophotographic light-­sensitive material.
• This light-sensitive material was negatively charged at -6 kV and then subjected to evaluation of the electrostatic characteristics, thus obtaining an initial potential (V o ) of -550 V, dark charge retention (D.R.R.) of 88% and half decay exposure (E 1/10 ) of 11.0 (lux ⁇ sec).
• the light-sensitive material was subjected to plate making in an analogous manner to Example 1 and the resulting master plate for offset printing had a clear image having a density of at least 1.0.
• the plate was subjected to oil-desensiti­zation by immersing for 30 seconds in the oil-desensi­tizing solution (E-1) used in Example 1 and washed with water.
• the non-image area of the resulting plate was sufficiently rendered hydrophilic as represented by a contact angle with distilled water of less than 10°.
• the print obtaining 10000 prints had a clear image and no fog on the non-image area.
• Example 1 was repeated except using copolymer resins (Resins A-26 to A-37 shown in Table 3) of the present invention instead of Resin A-2 of the present invention, thus obtaining electrophotographic light-­sensitive materials, each Resin A having an M w of 3x104 to 5x104.
• the resulting master plate had a density of at least 1.0 and clear image.
• the resulting master plate had a density of at least 1.0 and clear image.
• Example 3 was repeated except using compounds shown in Table 4 instead of Resin A-6 and 1,4-xylylene diisocyanate to be coated as the surface layer-of the photoreceptor, thus obtaining electrophotographic light-­sensitive materials, each having an ( M w) in the range of 3x104 to 6x104.
• the resulting master plate had a density of at least 1.0 and clear image.
• the resulting master plate had a density of at least 1.0 and clear image.
• a solution of 5% by weight (as solid content) of Resin A-7, 0.8% by weight of ethylene glycol dimeth­acrylate and 0.05% by weight of 1,1′-azobis(cyclohexane­1-carbonitrile) in toluene was coated on the resulting photoreceptor by a doctor blade and heated at 100°C for 3 hours to form a surface layer of about 2 ⁇ m thick. Then, the light-sensitive material was allowed to stand in a dark place at 20°C and 65% RH for 24 hours to prepare an electrophotographic light-sensitive material.
• Electrostatic Characteristics 1 V10: -585 (V) D.R.R.: 86% E 1/10 : 20 (erg/cm2) Image Quality 2) I (20°C, 65%): good II (30°C, 80%): good Contact Angle with Water 10° or less Printing Durability 3) 8000 prints
• the light-sensitive material of the present invention exhibited excellent electro­static characteristics and printing property.
• the electrostatic characteristics and image quality were measured by the following procedures:
• the light-sensitive material was subjected to corona discharge at -6kV for 20 seconds in a dark room at a temperature of 20°C and relative humidity of 65% using a paper analyzer (Paper Analyzer SP-428 -commercial name- manufacture by Kawaguchi Denki KK) and then allowed to stand for 10 seconds, at which the surface potential V10 was measured. Then, the sample was further allowed to stand in the dark room as it was for 60 seconds to measure the surface potential V70, thus obtaining the retention of potential after the dark decay for 60 seconds, i.e., dark decay retention ratio (DRR (%)) represented by (V70/V10)x100 (%).
• DRR dark decay retention ratio
• the surface of the photoconductive layer was negatively charged to -400 V by corona discharge, then irradiated with monochromatic light of a wavelength of 780 nm and the time required for dark decay of the surface potential (V10) to 1/10 was measured to evaluate an exposure quantity E 1/10 (erg/cm2).
• the light-sensitive material was allowed to stand for a whole day and night under the following ambient conditions, charged at -5 kV, imagewise exposed rapidly at a pitch of 25 ⁇ m and a scanning speed of 300 m/sec under irradiation of 64 erg/cm2 on the surface of the light-sensitive material using a gallium-aluminum-­arsenic semiconductor laser (oscillation wavelength: 780 nm) with an output of 2.8 mW as a light source, developed with a liquid developer, ELP-T (-commercial name-, manufactured by Fuji Photo Film Co., Ltd.) and fixed to obtain a reproduced image which was then subjected to visual evaluation of the fog and image quality: I 20°C, 65% RH II 30°C, 80% RH
• the light-sensitive material was immersed in an oil-desensitizing processing solution (E-3), prepared by the following recipe, for 30 seconds, followed by washing with water: Oil-desensitizing Processing Solution (E-3) Potassium Sulfite 80 g Neosoap (commercial name, made by Takemoto Jushi KK) 15 g Benzyl Alcohol 100 g These components were dissolved in distilled water to give a whole quantity of 1000 ml and the pH of the solution was adjusted to 11.5 with potassium hydroxide.
• E-3 oil-desensitizing processing solution
• the plate thus oil-desensitized was subjected to printing in an analogous manner to Example 1 so as to examine the printing durability.
• the light-sensitive material of the present invention exhibited excellent electro­static characteristics and printing property.
• the light-sensitive material was excellent in the electrostatic characteristics, dark charge retention and photosensitivity and gave a clear image without occurrence of the background fog and disappearance of fine lines even under severer conditions, e.g. high temperature and high humidity (30°C, 80% RH).
• the resulting master plate for offset printing had a concentration of at least 1.0 and clear image quality.
• 10000 or more prints with a clear image were obtained without occurrence of fog or non-­image areas.
• a mixture of 10 g (as solid content) of Resin A-­8, 10 g of zinc oxide and 100 g of toluene was dispersed in a ball mill for 2 hours, to which 2 g of ethylene glycol glycidyl ether was further added, and the mixture was then dispersed in the ball mill for 10 minutes to prepare a dispersion, which was applied to the surface of the resulting photoreceptor by a wire bar coater and heated at 110°C for 2 hours to form a surface layer of about 2.5 ⁇ m thick.
• the thus coated paper was allowed to stand in a dark place at 20°C and 65% RH for 24 hours to prepare an electrophotographic light-sensitive material.
• oil-desensitizing processing solution (E-4), prepared by the following recipe, for 20 seconds and washed with water.
• Oil-desensitizing Processing Solution (E-4) Mixed Solution of ELP - FS (commercial name, made by Fugi Photo Film Co., Ltd.) 865 g Ammonium Sulfite 85 g Methyl Ethyl Keltone 50 g
• the non-image area was sufficiently rendered hydrophilic as represented by a contact angle with water of less than 10°.
• the light-sensitive material of the present invention exhibited very excellent properties.
• Master plates for offset printing were prepared by using the light-sensitive materials prepared in Examples 1 to 27 and carrying out an etching treatment as follows:
• Distilled water was added to 0.5 mole of each of nucleophilic compounds shown in the following Table 5, 100 g of an organic solvent and 10 g of Newcol B4SN (commercial name, manufactured by Nippon Nyukazai KK) to 1000 ml and the pH thereof was adjusted to 10.0.
• Each of the light-sensitive materials was immersed and etched in the solution ELP-E diluted by 2 times with distilled water for 20 seconds and then immersed in the above described processing solution at 25°C for 1 minute.
• Example 5 Example Light sensitive Material Nucleophilic Compound Organic Solvent 29
• Example 2 sodium sulfite benzyl alcohol 30
• Example 3 monoethanolamine -do- 31
• Example 5 diethanolamine methyl ethyl ketone
• Example 6 thiomalic acid ethylene glycol 33
• Example 8 thiosalicylic acid benzyl alcohol 34
• Example 9 taurine isopropyl alcohol 35
• Example 11 4-sulfobenzenesulfinic acid benzyl alcohol
• Example 12 thioglycolic acid ethanol 37
• Example 16 2-mercaptoethylphosphonic acid dioxane
• Example 18 serine - 39
• Example 20 sodium thiosulfate methyl ethyl ketone 40
• Example 21 ammonium sulfite benzyl alcohol
• the each material was sufficiently rendered hydrophilic as represented by a contact angle with water of less than 10°.
• the print obtaining 10000 prints had a clear image and no fog on the non-image area.
• the electrophotographic photosensitive material obtained in Example 28 but before coating the surface layer was coated with a toluene solution containing 5% by weight of each of Resin A shown in the following Table 6 by a doctor blade and heated at 100°C for 30 seconds to form a surface layer with a thickness of about 2 ⁇ m.
• Each of the light-sensitive materials was irradiated by a high voltage mercury lamp of 400 W at an interval of 30 cm and then allowed to stand in a dark place for 24 hours under conditions of 20°C and 65% RH to prepare a master plate for lithographic printing.
• Example 1 The procedure of Example 1 was repeated except using Resin A-14 and 1% by weight of Resin B-1 having the following structure for forming the surface layer instead of Resin A-2 and 0.5% by weight of 1,3-xylylene diisocyanate, thus obtaining the similar results thereto.
• Example 2 The procedure of Example 2 was repeated except using, for forming the surface layer, 5% by weight of Resin A-13, 1% by weight of Resin B-2 having the following structure and 0.6% by weight of 1,3-xylylene diisocyanate instead of 5% by weight of Resin A-4 and 0.6% by weight of 1,6-hexane diisocyanate, and for oil-­desensitizing, an oil-desensitizing processing solution (E-5) prepared by the following recipe instead of Oil-­desensitizing Processing Solution E-2: Oil-desensitizing Processing Solution E-5 Thiomalic Acid 55 g Benzyl Alcohol 100 g Distilled Water to 1000 ml pH adjusted with NaOH 11.5 Thus, the similar results were obtained to Example 2.
• Example 3 The procedure of Example 3 was repeated except using, for forming the surface layer, 5% by weight of Resin A-15, 0.8% by weight of Resin B-3 having the following structure and 0.02% by weight of 2,2′-­azobisisobutyronitrile instead of 5% by weight of Resin A-6 and 0.75% by weight of 1,4-xylylene diisocyanate used in Example 3:
• Example 43 was repeated except using copolymers A-26 to A-37 shown in Table 3 instead of Resin A-14 of the present invention, thus obtaining electrophoto­graphic light-sensitive materials.
• the resulting master plate had a density of at least 1.2 and clear image.
• it was subjected to an etching treatment with the processing solution E-1 and printing further­ more, 10000 or more prints with a clear image were obtained without occurrence of fog on non-image areas.
• Example 45 was repeated except using compounds shown in the following Table 7 instead of Resin A-15, Resin B-3 and the asobis compound, coated as the surface layer of the photoreceptor in Example 45, thus obtaining electrophotographic light-sensitive materials.
• the crosslinking compounds were used in the predetermined amounts shown in Table 7 and the others were used in the same amounts as described in Example 45.
• a solution of 5% by weight (as solid content) of Resin A-17, 1% by weight of Resin B-3 and 0.05% by weight of 1,4-tetramethylenediamine in toluene was coated on the resulting photoreceptor by a doctor blade and heated at 100°C for 30 seconds and at 120°C for 1 hour to form a surface layer of about 2 ⁇ m thick. Then, the light-sensitive material was allowed to stand in a dark place at 20°C and 65% RH for 24 hours to prepare an electrophotographic light-sensitive material.
• the light-sensitive material of the present invention exhibited excellent electrostatic characteristics and printing property.
• the electro­static characteristics and image quality were measured in the same manner as in Example 27.
• a mixture of 6.0 g of Resin R-3, 34 g of Resin R-4, 200 g of zinc oxide, 0.018 g of the cyanine dye (II), 0.20 g of maleic anhydride and 300 g of toluene was dispersed in a ball mill for 3 hours to prepare a light-sensitive layer-forming composition, which was then applied to a paper rendered electrically conductive to give a dry coverage of 25 g/m2 by means of a wire bar coater, followed by drying at 110°C for 30 seconds. The thus coated paper was allowed to stand in a dark place at 20°C and 65% RH for 24 hours to prepare an electro­photographic light-sensitive material.
• a mixture of 10 g (as solid content) of Resin A-­15, 1.5 g of Resin B-3, 10 g of zinc oxide and 100 g of toluene was dispersed in a ball mill for 2 hours, to which 1 g of ethylene glycol diglycidyl ether was further added, and the mixture was then dispersed in the ball mill for 10 minutes to prepare a dispersion, which was applied to the surface of the resulting photo­receptor by a wire bar coater and heated at 110°C for 2 hours to form a surface layer of about 2.5 ⁇ m thick.
• the thus coated paper was allowed to stand in a dark place at 20°C and 65% RH for 24 hours to prepare an electrophotographic light-sensitive material.
• the light-sensitive material subjected to plate making was immersed in the oil-desensitizing processing solution (E-4), prepared in Example 28, for 20 seconds and washed with water.
• the non-image area was sufficiently rendered hydrophilic as represented by a contact angle with water of less than 10°.
• the light-sensitive material of the present invention exhibited very excellent properties.
• Master plates for offset printing were prepared by using the light-sensitive materials prepared in Examples 43 to 65 and carrying out an etching treatment as follows:
• Distilled water was added to 0.5 mole of each of nucleophilic compounds shown in the following Table 8, 100 g of an organic solvent and 10 g of Newcol B4SN (commercial name, manufactured by Nippon Nyukazai KK) to 1000 ml and the pH thereof was adjusted to 10.0.
• Each of the light-sensitive materials was immersed and etched in the solution ELP-E diluted by 2 times with distilled water for 20 seconds and then immersed in the above described processing solution at 25°C for 1 minute.
• Example 5 Example Light sensitive Material Nucleophilic Compound Organic Solvent 66
• Example 44 sodium sulfite benzyl alcohol 67
• Example 45 monoethanolamine -do- 68
• Example 47 diethanolamine methyl ethyl ketone 69
• Example 48 thiomalic acid ethylene glycol 70
• Example 50 thiosalicylic acid benzyl alcohol 71
• Example 53 4-sulfobenzenesulfinic acid benzyl alcohol 73
• Example 54 thioglycolic acid ethanol 74
• Example 58 2-mercaptoethylphosphonic acid dioxane 75
• Example 62 sodium thiosulfate methyl ethyl ketone 77
• Example 63 ammonium sulfite benzyl alcohol
• the each material was sufficiently rendered hydrophilic as represented by a contact angle with water of less than 10°.
• the print obtaining 10000 prints had a clear image and no fog on the non-image area.
• Example 64 was repeated except using resins shown in Table 9 instead of Resin A-17 and Resin B-3, used for forming the surface layer in Example 64, and omitting 1,4-tetramethylenediamine, thus preparing printing plate precursors.
• Each of the light-sensitive materials was irradiated by a high voltage mercury lamp of 400 W at an interval of 30 cm and then allowed to stand in a dark place for 24 hours under conditions of 20°C and 65% RH to prepare a master plate for lithographic printing.
• the light-sensitive material was subjected to plate making in an analogous manner to Example 64 and the resulting master plate for offset printing had a clear image having a density of at least 1.2.
• an electrophotographic lithographic printing plate precursor which does not deteriorate during long storage under severer conditions and which has excellent electrostatic characteristics as well as good printing properties.

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