CA1308595C

CA1308595C - Photosensitive composition

Info

Publication number: CA1308595C
Application number: CA000523494A
Authority: CA
Inventors: Toshiaki Aoai; Kazuo Maemoto; Akihiko Kamiya
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1985-11-22
Filing date: 1986-11-20
Publication date: 1992-10-13
Anticipated expiration: 2009-10-13
Also published as: DE3639757C2; DE3639757A1; US4983491A; GB8627867D0; GB2185120B; GB2185120A

Abstract

ABSTRACT OF THE DISCLOSURE
A photosensitive composition is described, comprising a diazonium compound and a polyurethane resin having a carboxyl group in its main chain.
The composition can be developed with an aqueous alkali developer to provide a lithographic printing plate having a long press life.

Description

PHOTOSENSITIVE COMPOSITION

This invention relates to a photosensitive composition and, more particularly, to a photosensitive composition which can be developed with an aqueous alkali developer and is useful for presensitized litho-graphic printing p7ate precursors to provide litho-graphic printing plates a long press life.
BACKGROUND OF THE INVENTION
Diazonium compounds are widely used as photo-sensitive materials for presensitized printingmaterials, and the most commonly employed are diazo resins typically exemplified by a formaldehyde condensate of p-diazodiphenylamine.
Compositions containing the diazo resins for forming a photosensitive layer of presensitized printing materials are classified into the type in which the diazo resin is used alone without using any binder as described, e.g., in U.S. Patent 2,714,066 and the type in which the diazo resin is mixed with a binder as described, e.g., in Japanese Patent Appli-cation (OPI) No. 30604/75 (the term "OPI" as used herein means "unex~mined published Japanese patent application'q)O
In many of the latest presensitized printing plate `~

precursors, the photosensitive layer comprises the diazonium compound and a polymeric binder to obtain the presensitized printing plate having long press life.
The photosensitive layer containing a polymer binder includes a so-called alkali development ~ype in which unexposed areas are removed (developed) with an aqueous alkali develope and a so-called solvent develcpment type in which unexposed areas are removed with an organic solvent type developer, and these types depend on the properties of the binder used. From the standpoint of safety and health of the working environment, the former alkali development type has lately attracted attention. Known methods of rendering binders alkali-developable include introduction of lS carboxylic acids into polymers by copolymerizing a carboxylic acid-containing comonomer as disclosed in Japanese Patent Application (OPI) No. 30604/75 or by reacting a hydroxyl group of polyvinyl alcohol with a cyclic acid anhydride, e.g., phthalic anhydride, as disclosed in U.S. Patent 2,861,058. However, the polymers obtained by these methods exhibit poor abrasion resistance arising from their structure, and presensi-tized lithographic printing plate precursors contain-ing such binders in the photosensitive layer only provide lithographic printing plates of _ow printing duraoility, i.e., short press life. On the other hand, polyvinyl acetal is ~ 308595 disadvantageous in that it provides presensitized printing plate l?recursors of organic solvent develop-ment type only, though forming a tough and abrasion resistant film.
In addition, polyurethane resins are known to exhibit excellent abrasion resistance. Examples of application of polyurethane resins include a combi-nation of a diazonium compound and a substantially linear polyurethane resin and a combination of a diazonium salt polycondensate and a branched polyurethane resin as described in U.S. Patent 3,660,097 corresponding to Japanese Patent Publication No. 36961/74 and U.S. Patent 4,337,307 corresponding to Japanese Patent Application (OPI) No. 94346/81. However, none of these polyurethane resins has an alkali-soluble lS group so that solubility in an aqueous alkali developer is insufficient in its nature. It has been, therefore, very difficult to carry out development without leaving some film undevelopedO
SUMMARY OF THE INVENTION
One object of this invention is to eliminate the above-described disadvantages associated with the conventional polymeric binders and to provide a novel photosensitive composition having excellent developability with an aqueous alkali developer and 1 30~5q5 long press life.
As a result of extensive investigations, it has now been found that the above objects can be accomplished by using a novel photosensitive compo-sition.
The present invention relates to a photo-sensitive composition containing one or more of a diazonium compound and one or more of a polyurethane resin having a carboxyl group in its main chain.
DETAILED DESCRIPTION OF THE INVENTION
The diazonium compounds which can be used in the present invention include those described in U.S. Patents 3,867,147 and 2,632,703, etc., and, in particular, diazo resins typically including conden-sates between aromatlc diazonium salts and, for example,active carbonyl-containing compounds, such as form-aldehyde. Preferred examples of the diazo resins include hexafluorophosphates, tetrafluoroborates or phosphates of a condensate between p-diazodiphenyl-amine and formaldehyde or acetaldehyde. Sulfonates(e.g., p-toluenesulfonate, dodecylbenzenesulfonate, 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonate, etc.), phosphinates (e.g., benzenephosphinate, etc.), hydroxyl-containing compound salts (e.g., 2,4-dihydroxybenzo-phenone salt) or organic carboxylic acid salts of 1 3~8~95 a condensate between p-diazodiphenylamine and form-aldehyde as described in U.S. Patent 3,300,309 are also pref~rred.
In addition, a mesitylenesulfonate of a condensate between 3-methoxy-4-diazo-diphenylamine and 4,4'-bis-methoxy-methyl-diphenyl ether as disclosed in Japanese Patent Application (OPI) No. 27141/83 is also suitably used.
The content of the diazonium compound in the photosensitive composition is from 1 to 50% by weight, and preferably from 3 to 20% by weight. If necessary, these diazonium compounds may be used in combinations of two or more thereof.
The polyurethane resins havin~ a carboxyl ~roup which can be used in the present invention pre-ferably include those having, as a basic skeleton, reaction products obtained by reacting diisocyanate compounds represented by formula (I) with carboxyl-containing diol compounds represented by formula (II) or (III).
Formula (I) is represented by OCN - Rl - NCO (I) wherein Rl represents a substituted or unsubstituted 1 30~595 divalent aliphatic or aromatic hydrocarbon residue.
If desired, R1 may have other functional groups inert to an isocyanate group, such as an ester group, a urethane group, an amido group, a ureido group, etc.
Formulae (II) and ( III ) are represented b~

R5 (II) ~OOH

HO-R3-Ar-R4-OH
IR5 (III) COOH

wherein R2 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsub-stituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group;
R3, R4 and R5 (which may be the same or different) each represents a single bond or a substituted or unsubstituted divalent aliphatic or aromatic hydrocarbon residue; and Ar represents a substituted or unsubstituted trivalent aromatic hydrocarbon residueO

R2 preferably represents a hydrogen atom, an alkyl group having from 1 to ~ carbon atoms, or an aryl group having from 6 to 15 carbon atoms.
R3, R4 or R5 pre~erably represents an alkylene ~roup having from 1 to 20 carbon atoms, or an arylene group having from 6 to 15 carbon toms, and more pre-ferably an alkylene group having from 1 to 8 carbon atoms. If necessary, R3 R4 or R5 may have other functional groups inert to an isocyanate group such as an ester group, a urethane group, an amido group, a ureido group, an ether group, etc. Any two or three of R2, R3, R4 and R5 may be taken together to form a ring.
Ar preferably represents an aromatic hydro-carbon residue having from 6 to 15 carbon atoms.
Preferable substituent described in the definition of groups R1, R2, R3, R4, R5 and Ar includes a cyano group, a nitro group, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom and an iodine atom), a -CONH2 group, a -COOR6 group, a OR6 group, a -NHCONHR6 group, a -NHCOOR6 group, a -NHCOR6 group, a -OCONHR6 group, a -CONHR6 group, etcO, wherein R6 represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to lO carbon atoms, or an aralkyl group having 7 to ll carbon atoms.

Specific examples of the diisocyanate com-pounds represented by formula ( I ) include aromatic diisocyanate compounds, e.g., 2,4-tolylene diisocyanate or a dimer thereof, 2,6-tolylene diisocyanate, p-xylyl-ene diisocyanate, metaxylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthylene diiso-cyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, etc.; aliphatic diisocyanate compounds, e.g., hexa-methylene diisocyanate, trimethylhexamethylene di-isocyanate, lysine diisocyanate, dimeric acid diiso-cyanate, etc.; alicyclic diisocyanate compounds, e.g., 1 3085~5 isophorone diisocyanate, 4,4'-methylenebis(cyclohexyl-isocyanate), methylcyclohexane-2,4 (or - 2,6) diiso-cyanate, 1,3-(isocyanatomethyl)cyclohexane, etc.; di-isocyanate compounds obtained by reacting diols and diisocyanates, e.g., an addition product of 1 mol of 1,3-butylene glycol and 2 mols of tolylene diiso-cyanate, etc.; and the like.
Specific examples of the carboxyl-containing diol compounds represented by formula (II) or (III) are 3,5-dihydroxybenzoic acid, 2,2-bis(hydroxymethyl)-propionic acid, 2,2-bis~hydroxyethyl)propionic acid, 2,2-bis(3-hydroxypropyl)propionic acid, 2,2-bis(hydroxy-methyl)acetic acid, bis(4-hydroxyphenyl)acetic acid, 4,4-bis(4-hydroxyphenyl)pentanoic acid, tartaric acid, etc.
The polyurethane resins of this invention may be formed by reacting one or more of the diisocyanate compounds of the formula (I) with one or more of the carboxyl-containing diol compounds of formulae (II) or (III)o In addition to the carboxyl-containing diol compounds, diol compounds which do not contain a carboxyl group and may contain other substituents inert to an isocyanate group may also be used in combi-nation to such an extent that does not reduce alkali 25 developability. Examples of such diol compounds 1 3085~5 include ethylene glycol, diethylene glycol, tr.iethylene glycol, tetraeth-ylene glycol, propylene glycol, di-propylene glycol, polyethylene ~lycol, polypropylene glycol, neopentyl glycol, 1,3-butylene glycol, 1,6-hexanediol, 2-butene-1,4-diol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-bis-3-hydroxyethoxycyclohexane, cyclo-hexanedimethanol, tricyclodecanedimethanol, hydrogenat-ed bisphenol A, hydrogenated bisphenol F, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, an e~hylene oxide adduct of bisphenol F, a propylene oxide adduct of bisphenol F, an ethylene oxide adduct of hydrogenated bisphenol A, a propylene oxide adduct of hydrogenated bisphenol A, hydroquinone dihydroxyethyl ether, p-xylylene glycol, dihydroxyethyl-sulfone, bis(2-hydroxyethyl)-2,4-tolyle,nedicarbamate, 2,4-tolylene-bis(2-hydroxyethylcarbamide~, bis(2-hydroxyethyl)m-xylylenecarbamate, bis(2-hydroxyethyl) phthalate, etc.
The polyurethane resins according to the present invention can be synthesized by heating the above-described diisocyanate compounds and diol com-pounds in an aprotic solvent in the presence of a known catalyst whose activity depends on the reactivity of each reactant. A preferred molar ratio of the diisocyanate compounds to diol compounds ranges from 1 30~595 0.8 : 1 to 1.2 : 1. When an isocyante group remains in the polymer terminals, the product is treated with alcohols, amines, etc., to ultimately produce a polymer containing no isocyanate.group.
In a particularly preferred embodiment of the present invention, carboxyl-containing polyurethane resins which further contain a hydroxyl group and/or a nitrile group, and more preferably a hydroxyl group, are employed. Such polyurethane resins can be obtained by reacting the above-described carboxyl-containing polyurethane resins with a halogen compound having a hydroxyl group and/or a nitrile group in the presence of a base to thereby replace a part of t.he carboxyl groups with a hydroxyl group and/or a nitrile group. Introduction of a nitrile group may also be effected by using a diol compound having a nitrile group in combination with the diol compound of formula (II) or (III).
The polyurethane resins having a carboxyl group which can be used in the present invention, other than poly-urethane resins above described may include those obtained by treating polyurethanes having carboxylate group with an acidO
The polyurethanes having carboxylate group are prepared by reacting amines represented by formula (IV) with prepolymers having isocyanate end-groups as is described in Japanese Patent Publication 7720/71.

1 3085q5 R' R R R' NH2-(CH2)n-CH-CH-N-CH-CH-(CH2)n-NH2 (IV) CO
A
COOMe whrein R and R' each represents a hydrogen atom, a lower alkyl group having from 1 to 6 carbon atoms, preferably a hydrogen atom or a methyl group; A represents -CH2-CH2-, -CH2-CH2-CH2 , ~ CH30 ~ , ~ , or ~ , Me represents Li, Na, K, Rb,Cs, NH4, NHR3, NH2R2 or NH3R", wherein R" represents an alkyl group having from 1 to 4 carbon atoms, and n represents an integer of O or 1.
Examples of such amines include those shown below.
NH2-CH2CH2-IN-cH2 CH2 NH2 CO

COOLi NH~-CH2CH-N-CH-CH2-NH2 CO-CH2-CH2-CH2-COoNa , etc.

Preferable prepolymers having isocyanate end-groups are obtained by reacting an excessive amount of di-isocyantes and diols. Preferable diisocyanate and diol include those used in the previous polyurethane preparation.
The polyurethane resins having a carboxyl group which can be used in the present invention may include those obtained by reacting polyurethanes having primary and/or secondary free hydroxyl group, and/or free amino group with a lactone having from 3 to 7 membered ring, an anhydride or epoxycarboxylic acid as is described in Japanese Patent Publication 24194/67. The above described polyurethanes composing a main chain are obtained by the reaction of compounds having two or more of active hydrogen atoms and polyisocyanates.
Preferable compounds having active hydrogen atoms include a polyester, a polyacetal, a polyether, a polythio-ether, a polyamide, a polyester, a polyesteramide, a conven~
tional saturated or unsaturated glycol, e.g., an ethylene glycol, an ethylene glycol condensate, a butanediol, 1,2-propane diol, 1,3-propanediol, a neopentylglycol, a dioxy-ethoxyhydroquinone, a butenediol, a dioxyethyldiene, a mono-or bis-alkoxylated aliphatic, alicyclic, aromatic, hetero-cyclic primary amine, e.g., N-methyldiethaneolamine, N-butyl-diethanolamine, N~N-bis-y-aminopropyl-N-methylamine~ ~-oleyl-diethanolamine, N-cyclohexyldiisopropanolamine, N,N-dioxy-1 3085q5 ethyl-p-toluidine, N,N-dioxypropylnaphthylamine, polyethoxy-lated N-butyldiehtanolamine, polypropoxylated N-methyldi-ehtanolamine (molecular weight 300 to 4,000), etc.
Examples of chain propagating agent include diethylenetriamine, triethylenetetramine, tetraethylene-pentamine, pentaethylenehexamine, hexaethylenepentamine, etc.
Diisocyantes used in the above described reaction to provide polyurethane are the same as those descrlbed in the previous polyurethane preparation process.
Examples of acid anhydrides to provide carboxylic acid group include a succinic acid anhydride, a maleic acid anhydride, a phthalic acid anhydride, a di-, tetra-, and hexa-hydrophthalic acid anhydride etc. Examples of lactones include ~-propiolactone, ~-butyrolactone, etc.
Examples of epoxycarboxylic acid include glycidic acid, etc.
The polyurethane resins according to the present invention preferably have a weight average molecular weight more than 1,000, and more preferably of from 5,000 to lO0,000.
These polyurethane resins may be used either individually or as a mixture of two or more thereof.
The content of the polyurethane resin binder in the photo-sensitive composition ranges from about 50 to 99.5~ by weight, and preerably from about 55 to 95~ by weight.

1 30~5~5 The photosensitive composition of this in-vention can further contain resins other than the above-descrlbed polyurethane resins in amounts up to 50~ by weight based on the polyurethane resins.
Other resins which may be used include polyamide resins, epoxy resins, polyacetal resins, acrylic resins, methacrylic resins, polystyrene resins, novolak type phenolic resins, and the like.

If desired, the photosensitive composition of the invention may contain various additives for improving performance properties, such as dyes, pig-ments, stabilizers, fillers, surface active agents, plasticizers, and the like. For example, dyes to be used suitably include oil-soluble dyes, such as Oil Red RR (C.l. 26105), Oil Scarlet #308 (C.I. 21260), Oil Blue (C.I. 74350), Methylene Blue (C.I. 52015), Crystal Violet (C.I. 42555), Victoria Pure Blue (C.I.
42595), etc. Examples of stabilizers to be used in-clude phosphoric acid, phosphorous acid, oxalic acid, p-toluenesulfonic acid, dipicolinic acid, malic acid, tartaric acid, 2-methoxy-4-hydroxy-5-benzoylbenzene-sulfonic acid, butylnaphthalenesulfonic acid, p-hydroxy-benzenesulfonic acid, etc.
The photosensitive composition according to the invention is usually dissolved in a solvent to form a coating composition, and the coating compo-sition is coated on an appropriate support to a drycoating weight of from about 0.1 to 5 g/m2, and prefer-ably from 0.3 to 3 g/m2, followed by drying.
Solvents to be used in the photosensitive coating composition include methanol, ethanol, iso-propanol, n-butanol, t-butanol, 2-methoxyethanol, l-methoxy-2-propanol, 2-ethoxyethanol, 2-methoxyethyl acetate, ethylene glycol, tetrahydrofuran, dioxane, dimethyl sulfoxide, N,N-dimethylformamide, acetone, methyl ethyl ketone, etc., and mixtures thereof.

Supports on which the photosensitive com-position is applied include paper, plastic resin-laminated paper (e.g., paper laminated with polyethylene, poly-propylene, polystyrene, etc.), metal plates (e.g., an aluminum (inclusive of aluminum alloys) plate, a zinc plate, a copper plate, etc.), plastic resin-films (e.g., film~ of cellulose diacetate, cellulose tri-acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, poly-ethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), 1 30~5q5 paper or plastic resin-films on which the above-described metal is laminated or vacuum-deposited, and the like.
Of these, an aluminum plate is particularly preferred because of its marked dimensional stability and low cost. A composite sheet composed of a polyethylene terephthalate film and an aluminum sheet thereon as described in Japanese Patent Publication No. 18327/73 is also preferably used.
When using a support having a metallic surface, particularly an aluminum surface, it is pre-ferable that the support is subjected to surface treat-ment to render its surface hydrophilic, such as graining, dipping in an aqueous solution of sodium silicate, potassium fluorozi.rconate, a phosphoric acid salt, etc., anodic oxidation, and the like. For example, an aluminum plate having been dipped in a sodium sili-cate aqueous solution as described in U.S. Patent 2,714,066, an aluminum plate having been anodically oxidized and then dipped in an alkali metal silicate aqueous solution as described in Japanese Patent Pub-lication No. 5125/72, and an aluminum support havingbeen subjected to a combination of mechanical grain-ing and electrolytic graining as described in U~S.
Patent 4,476,006 can be advantageously. The above described anodic oxidation can be carried out by apply-ing electric current to an aluminum plate as an anode in an electrolytic solution comprising one or more of aqueous or non-aqueous solutions of inorganic acids, e . g ., phosphoric aci~ , chromic acid , sulfuric acid , boric acid, etc., organic acids, e.g., oxalic acid, sulfamic acid, etc., or salts of these acids.
After the graining or anodic oxidation, the support may preferably be subjected to sealing treatment by dipping in a sodium silicate aqueous solution, hot water or a hot aqueous solutlon of an inorganic or organic salt, or treating in a steam bath. Further, silicate electrodeposition as described in U.S. Patent 3,658,662 is also effective as a surface treatment.
The photosensitive composition coated on the support is then exposed to light through a trans-parent original having a line or dot image and develop-ed with an aqueous developer to provide a relief image negative to the original.
Light sources to be used for exposure include a carbon arc lamp, a mercury lamp, a xenon lamp, a tungsten lamp, a metal halide lamp, etc.
The photosensitive composition in accordance with the present invention is excellent in solubility in organic solvents for preparation of a coating com-1 3085q5 Fosition and developability in the une~sed ~s with an alkaline developer after imagewise exposure to ligl~t. The resulting relief image exhibits satisfactory abrasion resistance, oil sensitivity and adhesion to supports, and, when used as a printing plate, provides a large number of satisfactory prints.
The present invention will now be illustrated in greater detail with reference to Synthesis Examples and Examples, but it should be understood that these examples are not deemed to limit the present invention.
Unless otherwise specified, all ratios, percents, etc., are by wieght.

In a 500 ml-volume three necked flask were charged 125 g of 4,4'-diphenylmethane diisocyanate, 67 g of 2,2-bis(hydroxymethyl)propior.ic acid and 290 ml of dioxane to form a solution. One gram of N,N-diethyl-aniline was added thereto, and the mixture was stirred at reflux for 6 hours. ~fter completion of the reaction, the reaction mixture was portionwise poured into a solution consisting of 4 liters of water and ml of acetic acid to precipitate the polymer.
Vacuum drying of the resulting solid gave 185 g of Polymer (A). Polymer (A) was found to have a carboxyl group content of 2.47 meq/g and a weight average mole-1 30~5q5 cular weight of 28,000 as determined by gel-permeation chromatography (polystyrene standard).

In the same manner as in Synthesis Example 1, the diisocyanate compound and diol compound as shown in Table 1 were reacted to prepare Polymers (B) to (M). The carboxyl group content in each polymer is also shown in Table 1. Each of Polymers (B) to (M) had a weight average molecular weight between 7,000 and 40,000 (polystyrene standard).

t 30~595 ~ . __ ___ h h O . ~i ~ ~l ~ ~
_ ~ , ~ ~ ~y ~ O
~_ D
-C W N 3 ~; w N ~
O n c ~ ~ --v t~

c~ ~ ~ 1~4 1 30~595 ~ , .. . .
~.,o~ ~ ~ ; ~
~ ~ ¦ E ~ ~ ~ ~ ~

,~ '~' ", C~ o ~

~ , 1~

- 1 3035~5 SYNTHE S I S_ EXAMP LE 14 Fourty grams of Polymer (A) as prepared in Synthesis Example 1 and 200 ml of dimethylformamide were charged in a 300 ml-volume round bottom flask 5 equipped with a condenser and a stirrer to form a solution. To the solution was added 6.3 g (0.062 mol) of triethylamine. After heating the mixture to 80C, 7.7 g (0.062 mol) of ethylene bromohydrin was added thereto dropwise over a period of 10 minutes with stirring. The stirring was continued for an additional two hoursr After completion of the reaction, the reaction solution was poured into a solution consist-ing of 4 liters of water and 200 ml of acetic acid while stirring to precipltate a white polymer. The lS polymer was separated by filtration, washed with water and vacuum dried to obtain 42 g of Polymer (a).
NMR analysis of Polymer (a) revealed that a part of the carboxyl groups had been replaced with a hydroxylethyl group. The content of the remaining carboxyl group was determined by titration and was found to be 1.21 meq/g.

Polyurethane polymers having a carboxyl group were prepared in the same manner as described in Synthesis Example 1 but using the diisocyanate 1 30~5~5 compounds and diol compounds shown in Table 2. Each of the resulting polymers was reacted with ethylene bromohydrin (E3H) or ethylene cyanobromide (Ecs) to obtain Polyurethane Polymers (b) to (n).
It was confirmed by NMR analysis that a hydroxyethyl group or a cyanoethyl group had been introduced in place of carboxyl group of the initial polyurethane resins. The resulting polymers were analyzed for molecular weight by gel-permeation chromatography and for remaining carboxyl group content by titration. The determined carboxyl group content is shown in Table 2.

1 3085q5 c ~o-~ ~ - ~ ~ - ~:;
C O ~ :~ ~ ' ~ ~3~'1 T O ~ C, T V
~ E~m~ ~ m ~ ~_ u . _......... o _ 3 .. 8 ~-u 8 ~I~ ~
~ o o o\o ~ ~ N ~ _ ~ ~
~ E ~ '~ ~

1 Z _ _ _ D _ ~ ~ .- ~ ~

~g ~ .__ R
O ~ ~ ~O ~

O ~ ~ ~ l ~ N

~^ ~: I V-V-V + !~
O ~ t~ ~ _ ~ ~ ~

vO a ~3 3~

E ~ r ~
~ 0~ ~ ~
~_ ~ ~ o o æ

a ~ ~ ~ ~ ~ ~, ~ _ ~ ._.
~o _ . ~, _ -CLI

a x o ~r ~uo C ~ ~ ; D

a ~ ô ~ u ( ~ - 1~ - - -m E~ ~ ~ /=(~ ~N~
U ~ ~ + ~ + ~) ~

C ~ ô ô ~ $ ô;

~ .
Vo ~^ ~ . _ ' . ' . .... .

1 3085q5 A 0.24 mm thick aLuminum sheet was grained with a nylon brush and an aqueous suspension of pumice having a particle size of 400 mesh and thoroughly washed wi.th water. The grained surface was etched by dipping in a 10 wt% sodium hydroxide aqueous solu-tion at 70C for 60 seconds, washed with running water, and neutralized with 20% nitric acid. The surface of the aluminum sheet was then subjected to electro-chemlcal graining according to the description ofJapanese Patent Application (OPI) No. 67507/78, i.e., in a l wt% nitric acid aqueous solution using an alter-nating wave current under electrolysis conditions f VA = 12.7 V, Vc = 9.1 V and an anodic electric lS amount of 160 coulomb/dm2. Subsequently, the sheet was desmutted by soaking in a 30 wt% sulfuric acid aqueous solution at 55C for 2 minutes. The sheet was therl subjected to anodic oxidation in a 7 wt%
sulfuric acid aqueous solution to form an aluminum oxide film of 2.0 g/m2. The sheet was soaked in a ,3 wt% sodium silicate aqueous solution at 70~C for 1 minute, washed with water, and dried.
A photosensitive coating composition having the following formulation was coated on the thus pre-pared aluminum suppor~ to a dry coating weight of 1 3085q5 2.0 g/m2 by means of a ~heeler, followed by drying at 80.C for 2 minutes.
Photosensitive Composition Formulation:

Dodecylbenzenesulfonate of a con- 0.5 g densate betw~en 4-diazodiphenylamine and formaldehyde Polyurethane resin of the invention 0.5 g (see Table 3) Oil-soluble dye (victoria Pure0.1 g Blue BOH) Phosphorous acid 0.05 g 2-Methoxyethanol 100 g Each of the resulting presensitized printing plate precursor5 was imagewise exposed to light emitted from PS Light tproduced by Fuji Photo Film Co., Ltd.) from a distance of 1 m for 1 minute and then dipped in a developer having the following formulation at room temperature for 1 minute. The unexposed area 15 was removed by lightly rubbing the surface with absorbent cotton to obtain lithographic Printing Plates (I) to (VI) having a bright blue image.
Developer Formulation:
Sodium sulfite 5 g Benzyl alcohol 30 g Sodium carbonate 5 g Sodium isopropylnaphthalenesulfonate 12 g Water 1000 ml 1 30g595 For comparison, Lithographic Printing Plate (VII) was produced in the same manner as described above, except for replacing the polymer of the present invention as used in the photosensitive coating com-position with a polyme~ having the following xepeatingunit, wherein the a/b/c/d molar ratio was 35/30/25/10, and the weight average molecular weight was 65,000 (poly-styrene standard):

-~CH2C)a (CH2CH)b ( 2j~c (CH2C
f =o C_N C=O COOH
OC2H4OH 4 9( ) Each of Lithographic Printing Plates (I) to (VII) was mounted on a printer "GTO" manufactured by Heidelberg Co., and printing was carried out on fine paper using a commercially available ink. There were obtained satisfactory prints as shown in Table 3.

Lithogra-phic Print-ing Plate Polymer Used Press Life Remark (I) Polyurethane (A) 150,000 prints Invention (II) Polyurethane (C) 130,000 prints "

TABLE 3 (cont'cl.) Lithogra-phlc Print-ing Plate Polymer Used Press Life Remark -(III) Polyurethane (E) 140,000 prints Invention (IV) Polyurethane (F) 150,000 prints "
(V) Polyurethane (J) 170,000 prints "
(VI) Polyurethane (L) 140,000 prints "

(VII) Comparative 100,000 prints Comparison polymer As can be seen from Table 3, Lithographic Printing Plates (I) to (VI) using the polyurethane resins according to the present invention are superior in printing press life to the comparative printing plate (VII).

A photosensitive coating composition having the followiny formulation was coated on an aluminum support prepared in the same manner as in Example 1 to a dry coating weight of 2.0 g/m2 by means of a wheeler, followed by drying at 80C for 2 minutes.
Photosensitive Coatin~ Composition Formulation:

4-n-dodecylbenzenesulfonate of a 0.5 g condensate between 4-diazodiphenyl-amine and formaldehyde Polyurethane Resin of the invention 5.0 g (see Table 4) Oil-soluble dye (Victoria Pure 0.1 g Blue BOH) 1 30~5q5 Malic acid 0.05 g 2,-Methoxyethanol 100 g Each of the resulting presensitized litho-graphic printing plate preculsors was imagewise exposed to light and developed in the same manner as in Example 1 to obtain Lithographic Printing Plates (VIII) to (XII).
For comparison, Lithographic Printing Plate (XIII) was produced in the same manner as described above, except for replacing the polyurethane resin of the present invention as used in the photosensitive coating composition with a polymer having the following repeating unit, wherein the a/b/c/d molar ratio was 9/24/58/9, and the weight average molecular weight was lS 55,000 (polystyrene standard):

CH2-C) ~ (CH2CH)C ~CH2C
C=O N C=O C=O

NH O OH

OH

Each of the resulting lithographic printing 1 30~5q5 plates was mounted on a printer *"KOR" manufactured by Heidelberg Co., and printing was carried out on fine paper using a commercially available ink. There were obtained prints ~s shown in Table 4.

Lithogra-phic Print-ina Plate Polymer Used Press Life remcrk (VIII) Polyurethane (a) 180,000 prints Invention (IX) Polyurethane (f) 180,000 prints "
(X) Polyurethane (i) 190,000 prints (XI) Polyurethane (l) 200,000 prints "
(XII) Polyurethane (n) 190,000 prints "

(XIII) Comparative 100,000 prints Comparison Polymer It can be seen from Table 4 that the litho-g_aphic printing plates using the polyu-ethane resins according to the present invention ara remarkably excellent in printing press life as compared with the comparative printing plate.
While the invention has been described in detail and with reference to specific embodiments 2~ thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

*Denotes Trade Mark

Claims

1. A photosensitive composition comprising one or more of a diazonium compound and one or more of a poly-urethane resin having a carboxyl group in its main chain, in an amount of from 0.90 to 3.07 meq/g.

2. A photosensitive composition as in claim 1, wherein said polyurethane resin is obtained by reacting at least one of diisocyanate compounds represented by formula (I):
OCN-R1-NCO (1) wherein R1 represents a substituted or unsubstituted divalent aliphatic or aromatic hydrocarbon residue, with at least one of diol compounds having a carboxyl group represented by the formulae (II) or (III):
(II) (III) wherein R2 represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsub-stituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted aryloxy group;
R3, R4 and R5, which may be the same or different, each represents a single bond or a substituted or unsubstituted divalent aliphatic or aromatic hydrocarbon residue; and Ar represents a substituted or unsubstituted trivalent aromatic hydrocarbon residue.

3. A photosensitive composition as in claim 2, wherein R2 represents a hydrogen atom, a substituted or unsubstituted alkyl group having from 1 to 8 carbon atoms, or a substituted or unsubstituted aryl group having from 6 to 15 carbon atoms; R3, R4 and R5 each represents a substituted or unsubstituted alkylene group having from 1 to 20 carbon atoms, or a substitut-ed or unsubstituted arylene group having from 6 to 15 carbon atoms; and Ar represents a substituted or unsubstituted aromatic group having from 6 to 15 carbon atoms.

4. A photosensitive composition as in claim 2, wherein a molar ratio of the diisocyanate compounds to the diol compounds is from 0.8 : 1 to 1.2 : 1.

5. A photosensitive composition as in claim 1, wherein said polyurethane resin further has a hydroxyl group or a nitrile group.

6. A photosensitive composition as in claim 1, wherein said polyurethane resin has a weight average molecular weight or from 5, 000 to 100,000.

7. A photosensitive composition as in claim 1, wherein said diazonium compound is present in an amount of from 1 to 50% by weight based on the composition.

8. A photosensitive composition as in claim 1, wherein said diazonium compound is present in an amount of from 3 to 20% by weight based on the compo-sition.

9. A photosensitive composition as in claim 1, wherein said polyurethane resin is present in an amount of from about 50 to 99.5% by weight based on the com-position.

10. A photosensitive composition as in claim 9, wherein said polyurethane resin is present in an amount of from about 55 to 95% by weight based on the com-position.