JP2641511B2 - Original plate for direct drawing type lithographic printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lithographic printing plate, and more particularly, to a direct-drawing lithographic printing plate suitable for an office printing plate.

(Prior Art) At present, a direct-drawing lithographic printing original plate having an image receiving layer on a support is widely used as an office printing original plate.
In order to make a plate, that is, to form an image on such a printing original plate, a method of drawing oil-based ink by hand on an image receiving layer or printing by a typewriter, an in-jet method, a transfer-type heat-sensitive method, or the like is generally adopted. In addition, a method of transferring and fixing a toner image formed on a photoreceptor through a charging, exposing and developing process using a plain paper electrophotographic copying machine (PPC) to an image receiving layer has recently started to be used. In any case, the printing plate reduction of the plate making machine is surface-treated with a desensitizing liquid (so-called etchant) to desensitize the non-image area,
Used as a printing plate for lithographic printing.

Conventional direct-drawing lithographic printing plate precursors have a back surface layer on one side of a support such as paper, and an image receiving layer as a surface layer on the other side via an intermediate layer. The back layer or the intermediate layer is formed of a water-soluble resin such as PVA starch, a water-dispersible resin such as a synthetic resin emulsion, and a pigment. The image receiving layer as a surface layer is formed of a pigment, a water-soluble resin, and a waterproofing agent.

As a representative example of such a direct drawing type lithographic printing plate precursor, a water-soluble resin binder such as PVA, an inorganic pigment such as silica, calcium carbonate, and the like, as described in U.S. Pat. It comprises a water-resistant agent such as a melamine-formaldehyde resin precondensate as a main component.

(Problems to be Solved by the Invention) However, in the conventional printing plate obtained in this manner, in order to improve printing durability, the amount of a water-proofing agent added is increased or a hydrophobic resin is used. Increasing the hydrophobicity improves the printing durability but decreases the hydrophilicity and causes printing smears. On the other hand, improving the hydrophilicity causes a problem that the water resistance deteriorates and the printing durability decreases. Was. Particularly, in a high-temperature use environment of 30 ° C. or more, the surface layer (image-receiving layer) was dissolved in the immersion water used for offset printing, and there were serious drawbacks such as reduced printing durability and print stains.

Further, the lithographic printing plate precursor draws an oil-based ink or the like as an image portion on the image receiving layer, and if the adhesiveness between the receiving layer and the oil-based ink is not good, even if the non-image portion has sufficient hydrophilicity, Even if such printing stains do not occur, there is also a problem that the oily ink in the image area is lost during printing, and as a result, the printing durability is reduced.

The present invention is to solve the problems of the direct drawing type lithographic printing plate precursor as described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a direct drawing type lithographic printing plate precursor which is excellent in desensitization property and which does not generate not only a uniform background stain but also a point-like background stain as an offset master plate.

An object of the present invention is to improve the adhesiveness between the oil-based ink and the image-receiving layer in the image area, and to maintain the hydrophilicity of the non-image area even when the number of printed sheets is increased in printing, without causing background smear. An object of the present invention is to provide a lithographic printing original plate having high printing durability.

(Means for Solving the Problems) The present invention relates to the following objects: (1) In a direct-drawing type lithographic printing plate precursor having an image receiving layer on a support, a particle size is contained in the image receiving layer. Is 0.005μ
(2) a support for direct drawing type lithographic printing, characterized in that it contains at least one kind of resin particles having a size of from m to 10 μm and containing at least one kind of functional group which generates a hydroxyl group by decomposition. In a direct-drawing lithographic printing plate precursor having an image receiving layer thereon, in the image receiving layer, the particle size is 0.005μ.
m to 10 μm, for at least one kind of resin particles containing at least one kind of functional group which generates a hydroxyl group by decomposition and at least one part of which is crosslinked, for direct drawing type lithographic printing. The original is achieved by:

In the present invention, the resin particles dispersed in the image receiving layer are hydrolyzed or hydrolyzed by a desensitizing liquid and immersion water used for printing to generate a carboxyl group.

Therefore, the direct-printing master of the present invention containing the resin particles in the image receiving layer, when drawing an oil-based ink or the like as an image portion on the image receiving layer, by the action of the lipophilic group in the resin particles. In addition, the adhesion between the receiving layer and the oil-based ink becomes good, and the printing durability is improved.

On the other hand, in the non-image area of the direct-printing type original plate of the present invention, the resin particles are hydrolyzed or hydrolyzed by a desensitizing liquid and immersion water to generate hydroxyl groups as described above, so that the resin particles become hydrophilic. It is clearly distinguished from the lipophilicity of the image area, and the printing ink does not adhere to the non-image during printing.

As described above, conventionally, an image portion is rendered hydrophobic by drawing an oil-based ink or the like on a hydrophilic resin. In the present invention, however, the lipophilic resin particles are treated with a non-image portion by surface treatment. Based on the completely different occurrence of hydrophilization, a novel lithographic lithographic printing plate precursor having both the advantages of hydrophilicity and hydrophobicity of the resin particles has been obtained.

The resin particles of the present invention contain at least one functional group that generates at least one hydroxyl group by decomposition as described above, and are at least partially crosslinked.

It is important that the resin particles are dispersed in the image receiving layer as particles separately from the binder resin which is the matrix of the image receiving layer.

Thus, the direct-printing original plate of the present invention forms a faithful image portion and a non-image portion, and provides a high-quality printed image free from background smear.

Moreover, since the resin particles are fixed by the binder resin, they are not peeled off during various processing steps, and the protective effect of the binder resin can be obtained. Therefore, it has excellent printing durability, is not affected by the environment at the time of plate making, and has excellent storage stability before processing.

When the resin particles generate hydroxyl groups, the hydrophilicity of the groups may cause the resin particles to flow out due to fountain solution or the like during printing.However, such a problem is solved by crosslinking at least a part of the resin particles. You.

Hereinafter, the resin containing at least one functional group that decomposes to generate at least one hydroxyl group (hereinafter, may be simply referred to as a hydroxyl group-forming functional group-containing resin) used in the present invention will be described in detail. .

The functional group contained in the hydroxyl group-forming functional group-containing resin of the present invention generates a hydroxyl group by decomposition,
At least one hydroxyl group is generated from one functional group.
It may be more than one.

According to one preferred embodiment of the present invention, the hydroxyl group-forming functional group-containing resin is a resin containing at least one functional group represented by the general formula (I) [-CL].

In the general formula (I) [-CL], L is _{-CO-Y 1, -CO-Z} -Y 2, -CH = CH-CH 3, Or Represents

However, R ₁ , R ₂ , and R ₃ may be the same or different, and represent a hydrogen atom, a hydrocarbon group, or —OR ′ (R ′ represents a hydrocarbon group), and Y ₁ , Y ₂ Z represents a hydrogen atom, a sulfur atom or an -NH- group, and X represents a sulfur atom or an oxygen atom.

The functional group represented by the general formula [-CL] generates a hydroxyl group by decomposition, and will be described in more detail below.

L is In the formula, R ₁ , R ₂ , and R ₃ may be the same or different from each other, and are preferably a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms which may be substituted (for example, a methyl group, An ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, an octadecyl group, a chloroethyl group, a methoxyethyl group, a methoxypropyl group, etc., and an alicyclic group which may be substituted (for example, a cyclopentyl group) , Cyclohexyl group, etc.), and optionally substituted aralkyl groups having 7 to 12 carbon atoms (for example, benzyl group, phenethyl group, fluorobenzyl group, chlorobenzyl group, methylbenzyl group, methoxybenzyl group, 3-phenylpropyl group, etc.) ) Or an optionally substituted aromatic group (eg, phenyl, naphthyl, chlorophenyl, tolyl, methoxyphenyl, methoxy) A carbonylphenyl group, a dichlorophenyl group, etc. or —C—R ′ (R ′ represents a hydrocarbon group, specifically the same substituents as the above-mentioned R ₁ , R ₂ , R ₃ hydrocarbon groups) Is shown).

When L represents —CO—Y ₁ , Y ₁ is preferably a linear or branched alkyl group having 1 to 6 carbon atoms which may be substituted (for example, methyl group, trichloromethyl group, trifluoromethyl group, A methoxymethyl group, a phenoxymethyl group, a 2,2,2-trifluoroethyl group, a t-butyl group, a hexylsafluoro-i-propyl group, etc., an aralkyl group having 7 to 9 carbon atoms which may be substituted (for example, benzyl) Group, phenethyl group, methylbenzyl group, trimethylbenzyl group,
Heptamethylbenzyl group, methoxybenzyl group, etc., and optionally substituted aryl group having 6 to 12 carbon atoms (for example, phenyl group, nitrophenyl group, cyanophenyl group, methanesulfonylphenyl group, methoxyphenyl group, butoxyphenyl group, chlorophenyl) Group, dichlorophenyl group,
Trifluoromethylphenyl group).

In the case where L represents -CO-Z-Y _2, Z represents an oxygen atom, a sulfur atom or an -NH- bond group, Y ₂ is the same meaning as Y ₁ described above.

L is X represents an oxygen atom or a sulfur atom.

The resin having at least one functional group selected from the group of the general formula [-OL-] used in the present invention is obtained by reacting a hydroxyl group contained in a polymer with a polymer represented by the general formula [- O-L-], or one or more monomers containing one or more functional groups of the general formula [-OL-], or It is produced by a method of polymerizing by a polymerization reaction of another monomer copolymerizable therewith.

For example, as a method for producing the above polymer reaction, Yoshio Iwakura
Keisuke Kurita, "Reactive Polymers", p. 158 (published by Kodansha) and the like, and the hydroxyl group of a monomer is represented by the general formula [-OL-].
For the production method of converting to the functional group of "Nippon Kagaku Kagaku", "New Experimental Chemistry Course Vol. 14, Synthesis and Reaction of Organic Compounds [V]"
The method described on page 2497 (published by Maruzen Co., Ltd.) can be employed.

The polymer contains a functional group of the general formula [-OL-] in advance because the functional group of the general formula [-OL-] in the polymer can be adjusted arbitrarily or impurities are not mixed. It is preferable to use a method of producing the monomer by a polymerization reaction from the monomer.
Specifically, a compound containing a polymerizable double bond and containing at least one hydroxyl group can be converted into a compound represented by the general formula [-O- L-] or by reacting a compound containing a functional group of the general formula [-OL-] with a compound containing a polymerizable double bond. .

As described above, the monomer having a functional group of the general formula [-OL-] used in the method for producing a desired resin by a polymerization reaction is more specifically described, for example, by the following general formula (II) And the like.

General formula (II) In the formula (II), X 'is -O-, -CO-, -COO-, -OCO
−, _{-CH 2 COO -, - CH 2} OCO-, Represents an aromatic group or a heterocyclic group (provided that Q ₁ , Q ₂ , Q ₃ , Q ₄
Is a hydrogen atom, a hydrocarbon group, or Y ′ in formula (II)
-O-L] represents, b _1, b ₂ may connexion different be the same, a hydrogen atom, a hydrocarbon group or the formula (II) in the (Y'-O
-L), and n represents an integer of 0 to 18].

Y ′ represents a carbon-carbon bond which may be via a hetero atom connecting the bonding group X ′ and the bonding group [—OL] (hetero atoms include an oxygen atom, a sulfur atom and a nitrogen atom), For example -(CH = CH)-, -O-, -S-, -COO -, - CONH -, - SO 2 -, - SO 2 NH -, - NHCOO-,
Which has the constitution alone or in combination of coupling units such as -NHCONH- (where b _3, b _4, b ₅ are each the same meaning as the b _1, b _2).

 L has the same meaning as in formula (I).

a ₁ and a ₂ may be the same or different, and represent a hydrogen atom, a hydrocarbon group (for example, an alkyl group having 1 to 12 carbon atoms which may be substituted with -COOH or the like), -COOH or -COO-W [W And represents an alkyl group having 1 to 18 carbon atoms which may be substituted with a substituent containing a group represented by the general formula (-OL), an alekenyl group, an aralkyl group, an alicyclic group, or an aromatic group].

More specifically, examples of the monomer having a functional group of the general formula (-OL) include the following compound examples.

(However, Me represents a methyl group.) These monomers may be polymerized alone, or may be used as a copolymer in combination with other monomers copolymerizable with these monomers. . Other monomers to be copolymerized include, for example, aliphatic vinyl carboxylate or allyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, allyl acetate, allyl propionate, etc., acrylic acid, methacrylic acid, crotonic acid, Esters or amides of unsaturated carboxylic acids such as itaconic acid, maleic acid, fumaric acid, etc., styrene derivatives such as styrene, vinyltoluene, α-methylstyrene, α-olefins, acrylonitrile, methacrylonitrile, N-vinyl Examples include a vinyl group-substituted heterocyclic compound such as pyrrolidone.

According to another preferred embodiment of the present invention, the hydroxyl group-forming functional group-containing resin has at least one functional group having at least two hydroxyl groups located sterically close to each other in a form simultaneously protected by one protective group. Seed-containing resin.

Examples of functional groups having at least two hydroxyl groups at positions sterically close to each other in one protected form include, for example, the following general formulas (III), (IV), (V) and (V)
Those represented by I) can be mentioned.

General formula (III) In the formula (III), R ₄ and R ₅ may be the same or different and each represents a hydrogen atom, a hydrocarbon group or —O—R ″ (R ″ represents a hydrocarbon group); Represents a carbon-carbon bond which may be via an atom (provided that the number of atoms between oxygen atoms is within 5).

General formula (IV) In the formula (IV), U is as defined above.

General formula (V) In the formula (V), R ₄ R ₆ and U are as defined above.

General formula (VI) In the formula (VI), R ₄ and R ₅ are as defined above. R ₆ is a hydrogen atom or an aliphatic group having 1 to 8 carbon atoms (eg, a methyl group,
Alkyl group such as ethyl group, propyl group and butyl group, or aralkyl group such as benzyl group, phenethyl group, methylbenzyl group, meoxybenzyl group and chlorobedinyl group).

The functional group will be described in more detail below.

In the formula (III), R ₄ and R ₅ may be the same or different and are preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may be substituted (for example, a methyl group, an ethyl group, a propyl group, a butyl group). Group, hexyl group, 2-methoxyethyl group, octyl group, etc.) and optionally substituted aralkyl group having 7 to 9 carbon atoms (eg, benzyl group, phenethyl group, methylbenzyl group, methoxybenzyl group, chlorobenzyl group, etc.) An alicyclic group having 5 to 7 carbon atoms (eg, cyclopentyl group, cyclohexyl group, etc.), an optionally substituted aryl group (eg, phenyl group, chlorophenyl group, methoxyphenyl group, methylphenyl group, cyanophenyl group, etc.) or- O
-R (R is R _4, the same meaning as the hydrocarbon group for R ₅₎ represents a.

U represents a carbon-carbon bond which may be via a hetero atom, and the number of atoms between oxygen atoms is 5 or less.

The resin containing at least one functional group used in the present invention is in a form in which hydroxyl groups contained in the polymer and located at positions close to each other sterically as described above are protected by a protective group by a polymer reaction. Prepared by a method of polymerizing a monomer containing at least two hydroxyl groups in a form previously protected by a protecting group, or a polymerization reaction of the monomer and another monomer copolymerizable therewith. Is done.

As the production method by the former polymer reaction, for example, a polymer component having at least two hydroxyl groups in close proximity or a polymer component capable of having in close proximity after polymerization as exemplified below. (R ″ is H or a substituent such as CH ₃ ) (X ′ represents a linking group), by reacting the polymer with a compound such as a carbonyl compound, an orthoester compound, a halogen-substituted formate, a dihalogen-substituted silyl, etc. It is possible to form a functional group having one protected group at the same time protected.

Specifically, "The New Experimental Chemistry, Vol. 14, Synthesis and Reaction of Organic Compounds [V]", edited by The Chemical Society of Japan, page 2505 (published by Maruzen Co., Ltd.), JFW McOmie, "Protectivegroups in Organic Ch.
emistry ”, Chapters 3 and 4 (Plenum. Press) and the like.

In addition, the latter method based on the polymerization reaction includes at least 2
After synthesizing a monomer having two hydroxyl groups protected in advance by a known method described in the above-mentioned literature, if necessary, co-exist with another monomer which can be copolymerized with the monomer, and perform ordinary polymerization. By polymerizing by the method, a homopolymer or a multi-component copolymer can be produced.

More specifically, examples of the polymer component containing the functional group include the following.

The polymer component containing a hydroxyl group-forming functional group in the resin of the present invention, when the resin is a copolymer, preferably accounts for 1 to 95% by weight, more preferably 5 to 60% by weight, based on the whole polymer. . The molecular weight of the resin polymer is 10 ³ to 10 ⁶ ,
In particular, it is preferably from 5 × 10 ^{3 to} 5 × 10 ⁵ .

When the resin of the present invention is a copolymer, examples of the monomer that can be copolymerized with the monomer containing a hydroxyl group-forming functional group described above include, for example, α-olefins, vinyl alkanoates, or allyl esters, Acrylonitrile, methacrylonitrile, vinyl ethers, acrylamides, methacrylamides, styrenes, heterocyclic vinyls (for example, vinylpyrrolidone, vinylpyridine, vinylimidazole, vinylthiophene, vinylimidazoline, vinylpyrazole, vinyl-dioxane, vinylkyrin, vinylthiazole , Vinyl-oxazine, etc.). Especially vinyl acetate, allyl acetate, acrylonitrile,
Methacrylonitrile, styrenes, etc. are preferred components from the viewpoint of improving the film strength.

In the present invention, at least a part of the above resin may be crosslinked.

A resin in which at least a part of the polymer has been cross-linked in advance (a resin having a cross-linked structure in the polymer) becomes acidic when the hydroxyl group-forming functional group contained in the resin generates a hydroxyl group by decomposition. And a resin which is hardly soluble or insoluble in an alkaline aqueous solution.

Specifically, it has a solubility of preferably 90% by weight or less, more preferably 70% by weight or less at a temperature of 20 to 25 ° C. in distilled water.

As a method for introducing a crosslinked structure into the polymer, a generally known method can be used.

That is, a polymer containing a functional group that generates a hydroxyl group by decomposition contains a functional group that proceeds with a crosslinking reaction, and the polymer containing both functional groups is crosslinked with various crosslinking agents or curing agents. Or a method of subjecting these polymers to a polymerization reaction (a method of crosslinking by a polymer reaction, or a method of crosslinking at least one monomer corresponding to a polymer component having a functional group capable of forming a hydroxyl group by decomposition). When performing a polymerization reaction by containing species, a method of cross-linking between molecules by coexisting a polyfunctional monomer or a polyfunctional oligomer having two or more polymerizable functional groups) is used. Can be.

In the present invention, the functional group that progresses the cross-linking reaction may be any of a normal polymerizable double bond group or a reactive group bonded by a chemical reaction.

As the polymerizable double bond group, specifically, CH ₂ CHCH—CH ₂ —, CH ₂ = CH-, CH ₂ = CH-CONH-, _{CH 2 = CH-NHCO-, CH} 2 = CH-CH 2 -NHCO-, CH 2 = CH-SO 2 -, CH 2 = CH-CO-, CH 2 = CH-O-, CH 2 = CH-S -And the like.

When a chemical bond is formed by a reaction between reactive groups to form a bridge between polymers, the reaction can be carried out in the same manner as a reaction of an ordinary organic low-molecular compound. In particular,
Yoshio Iwakura, Keisuke Kurita "Reactive Polymers" Kodansha (1977), Ryohei Oda "Polymer Fine Chemicals" Kodansha (19
1976).

For example, in Table 1, a chemical bond by a combination of a functional group of Group A and a functional group of Group B is usually well known.

Examples of the reactive group also include -CONHCH ₂ OR (R represents a hydrogen atom or an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group), and the reactive group is bonded by a self-condensation reaction. It is known as a base and can be used.

As the cross-linking agent in the present invention, a compound usually used as a cross-linking agent can be used. In particular,
Compounds described in Shinzo Yamashita, Tosuke Kaneko, "Crosslinking Handbook" Taiseisha (1981), edited by The Society of Polymer Science, "Polymer Data Handbook" Basic Edition "", Baifukan (1986), etc. can be used. .

For example, organic silane-based compounds (for example, silane coupling agents such as vinyltrimethoxysilane, vinyltributoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane, etc.) ), Polyisocyanate compounds (eg, toluylene diisocyanate, o-toluylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, hexamethylene diisocyanate, isophorone diisocyanate) Isocyanates, polymer polyisocyanates, etc.), polyol compounds (eg, 1,4-butanediol, polyoxypropylene glycol, polyoxyalkylene glycol,
1,1-trimethylolpropane, etc.), polyamine-based compounds (eg, ethylenediamine, γ-hydroxypropylated ethylenediamine, phenylenediamine, hexamethylenediamine, N-aminoethylpiperazine, modified aliphatic polyamines, etc.), containing polyepoxy groups Compounds and epoxy resins (for example, "New Epoxy Resins" edited by Hiroshi Kakiuchi, Shokodo (1985), "Epoxy Resins" edited by Kuniyuki Hashimoto, compounds described in Nikkan Kogyo Shimbun (1969), etc.), melamine resins (for example, Compounds described in "Area Melamine Resin", edited by Ichiro Miwa and Hideo Matsunaga, Nikkan Kogyo Shimbun (1969), etc., and poly (meth) acrylate compounds (for example, "Oligomers" edited by Shin Okawara, Takeo Saegusa, Toshinobu Higashimura Kodansha (1976), Eizo Omori "Functional Acrylic Resin" Techno System (1985), etc. Include the described compounds are, specifically polyethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6
Hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol polyacrylate, bisphenol A-diglycidyl ether diacrylate, oligoester acrylate: these methacrylates and the like].

Further, the polymerizable functional group used in the above polymerization reaction is 2
As a polyfunctional monomer or oligomer having at least two
For example, monomers having the same polymerizable functional group include styrene derivatives such as divinylbenzene and trivinylbenzene: polyhydric alcohols (eg, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol # 200, # 400, # 600, Methacrylic acid of 1,3-butylene glycol, neopentyl glycol, dipropylene glycol, polypropylene glycol, trimethylolpropane, trimethylolethane, pentaerythritol or the like or polyhydroxyphenol (for example, hydroquinone, resorcin, catechol and derivatives thereof), Esters, vinyl ethers or allyl ethers of acrylic acid or crotonic acid: dibasic acids (for example, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, Vinyl esters, allyl esters, vinylamides or allylamides of tallic acid, itaconic acid, etc .: polyamines (eg, ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, etc.) and carboxylic acids containing vinyl groups (Eg, methacrylic acid, acrylic acid, crotonic acid, allyl acetic acid, etc.).

Examples of polyfunctional monomers or oligomers having different polymerizable functional groups include, for example, carboxylic acids having a vinyl group [eg, methacrylic acid, acrylic acid, methacryloylacetic acid, acryloylacetic acid, methacryloylpropionic acid, acryloylpropionic acid, Itaconiloyl acetic acid,
Vinyl group of reactants of itaconiloylpropionic acid, carboxylic anhydride and alcohol or amine (eg, allyloxycarbonylpropionic acid, allyloxycarbonylacetic acid, 2-allyloxycarbonylbenzoic acid, allylaminocarbonylpropionic acid, etc.) Ester derivatives or amide derivatives containing (eg, vinyl methacrylate,
Vinyl acrylate, vinyl itaconate, allyl methacrylate, allyl acrylate, allyl itaconate, vinyl methacryloyl acetate, vinyl methacryloyl propionate, allyl methacryloyl propionate, vinyloxycarbonylmethyl methacrylate, vinyloxycarbonylmethyloxycarbonyl acrylate Ethylene ester, N-allylacrylamide, N-allylmethacrylamide, N-allylitaconamide, methacryloylpropionic allylamide, etc., or amino alcohols (for example, aminoethanol, 1-aminopropanol, 1-
Condensates of aminobutanol, 1-aminohexanol, 2-aminobutanol, etc.) and a carboxylic acid containing a vinyl group.

The monomer or oligomer having two or more polymerizable functional groups used in the present invention is polymerized using 10% by weight or less, preferably 5% by weight or less of all monomers to form a resin.

As described above, the resin containing at least one functional group that generates at least one hydroxyl group by decomposition and partially crosslinked has a particle state in the present invention.

When the resin particles of the present invention have an excessively large particle size, the oil-based ink or the like does not uniformly adhere during image drawing, and it becomes difficult to form a clear image portion. Preferably, there is.

Specifically, the resin particles of the present invention have a maximum particle size of
It is 10 μm or less, preferably 5 μm or less. And. The average particle size of the resin particles is 1.0 μm or less, preferably 0.5 μm or less. The smaller the particle size of the resin particles, the larger the specific surface area and the above-mentioned effect on image drawing is obtained. Even if the colloidal particles (0.01 μm or less) are sufficient, if the particle size is too small, the case of molecular dispersion may occur. Since the same adverse effects occur, it is preferable that the thickness is 0.005 μm or more.

The resin particles of the present invention having such a fine particle diameter can be adjusted to a desired particle size by dispersing the resin powder as it is when preparing the composition for forming an image receiving layer. Alternatively, it is also possible to use a conventionally known dry or wet partial particle forming method, or a method using a polymer gel latex.

That is, a method of directly pulverizing a resin powder with a conventionally known pulverizer / disperser to obtain fine particles (for example, a ball mill, a paint shaker, a sound mill, a hammer mill, a jet mill, a Keddy mill, etc.) and a conventionally known paint or A method for producing latex particles of a liquid developer for electrostatography can be used. The latter method of polymer latex is a method of dispersing a resin powder in combination with a dispersing polymer, kneading the resin powder and a dispersion auxiliary polymer in advance to form a kneaded product, pulverizing, and then There is a mechanical method such as a method in which a dispersed polymer coexists and is dispersed.

Specifically, for example, Kenji Ueki, “Flow and paint dispersion of paint”, Kyoritsu Shuppan (1971), “Solomon, Chemistry of paint”, “Paint and Surface Coating theory and pract”
ice), Yuji Harasaki "Coating Engineering" Asakura Shoten (1971)
Yuji Harasaki, "Basic Chemistry of Coating", Maki Shoten (19
77), JP-A-62-96954, JP-A-62-115171, and JP-A-62-7
No. 5651, etc.

In addition, a method of easily obtaining latex particles by a conventionally known polymerization reaction such as a suspension polymerization method or a dispersion polymerization method can also be used.

Specifically, Soichi Muroi, Chemistry of Polymer Latex, Polymer Publishing Society (1970), Taira Okuda, Hiroshi Inagaki, Synthetic Resin Emulsion, Polymer Publication Society (1978), Soichi Muroi, Introduction to Polymer Latex "Koubunsha (1983).

In the present invention, a method of using polymer latex particles is preferable, and resin particles having an average particle diameter of 1.0 μm or less can be easily obtained by this method.

The latex particles of the present invention may be either hydrogen or non-aqueous latex particles.

The non-aqueous solvent used in the non-aqueous latex may be any organic solvent having a boiling point of 200 ° C. or lower, and may be used alone or as a mixture of two or more.

Specific examples of this organic solvent include methanol, ethanol,
Alcohols such as propanol, butanol, fluorinated alcohol and benzyl alcohol; ketones such as acetone, methyl ethyl ketone, cyclohexanone and diethyl ketone; ethers such as diethyl ether, tetrahydrofuran and dioxane; methyl acetate, ethyl acetate, butyl acetate and propionic acid Carboxylic esters such as methyl,
Hexane, octane, decane, dodecane, tridecane,
C6-14 aliphatic hydrocarbons such as cyclohexane and cyclooctane; aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene; methylene chloride;
Dichloroethane, tetrachloroethane, chloroform,
Halogenated hydrocarbons such as methyl chloroform, dichloropropane, and trichloroethane are exemplified.

In these non-aqueous solvent systems, a method for synthesizing a polymer latex by a dispersion polymerization method is such that the average particle size of the latex particles is easily reduced to 1 μm or less, and the particle size distribution is very narrow, and monodisperse particles are used. can do. Specifically, KEJ Barrett, “Dispersion Polymerization in O
rganic Media "John Wiley (1975), Koichiro Murata, Polymer Processing, 23 , 20 (1974), Tsunetaka Matsumoto and Tokichi Tange, Journal of the Adhesion Society of Japan 9 , 183 (1973), Toyokichi Tange, Journal of the Japan Adhesion Association
23 , 26 (1987), DJ Walbridge, NATO Adv.study, Iust.Se
rENo.67,40 (1983), BP893429, BP934038, USP
No. 1122397, USP390412, USP4606989, JP-A-60-1790
Nos. 51 and 60-185963 disclose the method.

The above resin particles in the present invention are hydrolyzed or hydrogenolyzed by a desensitizing liquid or a fountain solution used for printing to generate hydroxyl groups.

Therefore, in the original plate of the present invention containing the resin particles in the image receiving layer, the hydrophilicity of the non-image portion to be hydrophilized by the desensitizing solution is changed by the hydroxyl groups generated by the resin particles. As a result, the lipophilicity of the image area and the hydrophilicity of the non-image area become clear, and the printing ink is prevented from adhering to the non-image area during printing. As a result, it is possible to print a large number of prints of clear image quality without background contamination.

Further, in the case of the above resin particles partially crosslinked, the solubility in water is remarkably reduced while maintaining hydrophilicity, and the resin particles become hardly soluble or insoluble.

Therefore, the effect of further increasing the hydrophilicity of the non-image area by the hydroxyl groups generated by the resin particles is improved, and the durability is improved.

More specifically, even if the amount of the functional group in the resin particles is reduced, the effect of improving the hydrophilicity can be maintained without change, or a large win of a printing machine or a change in printing pressure. Even when the printing conditions are severe, it is possible to print a large number of prints of clear image quality without background contamination.

The resin particles of the present invention, when the amount is too small, the above-mentioned effects are lost, while when the amount is too large, the hydrophilicity of the non-image portion is improved, but the etching speed is reduced, so that the matrix resin of the image receiving layer is reduced. It is 0.1 to 80% by weight, preferably 1 to 50% by weight, based on 100 parts by weight.

Further, as the matrix resin provided for the image receiving layer of the present invention, all of those conventionally known as various binder resins can be used. A typical example is vinyl chloride.
Vinyl acetate copolymer, styrene-butadiene copolymer,
Styrene-methacrylate copolymer, methacrylate copolymer, acrylate copolymer, vinyl acetate copolymer,
Polyvinyl butyral, alkyd resin, silicone resin, epoxy resin, epoxy ester resin, polyester resin, etc., or as a water-soluble polymer compound, polyvinyl alcohol, modified polyvinyl alcohol, starch, oxidized starch, carboxymethyl cellulose, hydroxyethyl cellulose, casein, gelatin, Polyacrylate,
Polyvinylpyrrolidone, polyvinyl ether-maleic anhydride copolymer, polyamide, polyacrylamide and the like can be mentioned.

The molecular weight of the matrix resin used in the image receiving layer of the present invention is preferably 10 ³ to 10 ⁶ , more preferably 5 × 10 ³ to
It is 5 × 10 ⁵ . The glass transition point of the binder resin is preferably from -10C to 120C, more preferably from 0C to 85C.

The matrix resin described above functions to disperse and fix the resin particles that generate hydroxyl groups by the decomposition described above in the image receiving layer, and to adhere the image receiving layer to the support or the intermediate layer.

As described above, the present invention uses a resin having a functional group that generates a hydroxyl group by decomposition in a molecular state because it is used separately from a matrix resin and is dispersed in a particle state. The specific surface area is increased as compared with the above, and the easiness of generation of a hydroxyl group by the desensitizing treatment and the degree of hydrophilization by the generated hydroxyl group are further enhanced.

As another component of the image receiving layer of the present invention, an inorganic pigment is used. As the inorganic pigment, for example, kaolin clay, calcium carbonate, silica, titanium oxide, zinc oxide,
Examples include barium sulfate and alumina.

The ratio of the binder resin / pigment in the image receiving layer differs depending on the kind of the material and the particle size in the case of the pigment, but is generally 1 / (0.5 to 5) by weight ratio, preferably 1 / (0.8 to 2.5). ) The degree is appropriate.

In addition, a crosslinking agent may be added to the image receiving layer in order to further improve the film strength. Examples of the crosslinking agent include commonly used ammonium chloride, organic oxides, metal soaps,
An organic silane, a crosslinking agent for polyurethane, a curing agent for epoxy resin, or the like can be used. Specifically, Shinzo Yamashita,
Tosuke Kaneko, "Handbook of Crosslinking Agents," Taiseisha Publishing (1981)
And so on.

Examples of the support used in the present invention include high-quality paper, wet-strengthened paper, plastic films such as polyester films, and metal plates such as aluminum plates.

In the present invention, an intermediate layer is provided between the support and the image receiving layer for the purpose of improving water resistance and interlayer adhesion, and a back coat layer (backside layer) is provided on the side of the support opposite to the image receiving layer for the purpose of preventing curling. Can be provided.

Here, the intermediate layer is an emulsion resin such as acrylic resin, ethylene-butadiene copolymer, methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, ethylene-vinyl acetate copolymer; epoxy resin, polyvinyl butyral , Polyvinyl chloride, polyvinyl acetate, etc .; a solvent type resin; as mentioned above, it is composed of at least one kind such as a water-soluble resin, but it is necessary to add an inorganic pigment or a water-proofing agent as necessary. Can be.

 The configuration of the back coat layer is almost the same as that of the intermediate layer.

When used as a PPC plate making, in order to always reduce so scumming printing plate precursor of the present invention, as the volume resistivity of the printing plate is 10 ¹⁰ to 10 ¹³ [Omega] cm, further substituted receiving layer, an intermediate layer And / or a dielectric agent can be added to the backcoat layer. The dielectric agent may be an inorganic one or an organic one. In the case of an inorganic one, Na, K, Li,
Salts of monovalent or polyvalent metals such as Mg, Zn, Co, Ni, etc., and organic cation conductive agents such as polyvinylbenzyltrimethylammonium chloride and quaternary ammonium salts modified with acrylic resin, and organic sulfonic acids Polymeric anionic dielectric agents such as salts are included. The addition amount of these dielectric agents is 3 to 40% by weight, preferably 5 to 20% by weight of the binder amount used for each layer.

In order to produce the direct-lithographic lithographic printing plate precursor according to the invention, generally, if necessary, a liquid containing an intermediate layer component is applied to one surface of the support, followed by drying to form an intermediate layer. The liquid may be applied and dried to form an image receiving layer, and if necessary, a liquid containing a back coat layer component may be applied and dried on the other surface to form a back coat layer. The amount of each of the image receiving layer, the intermediate layer, and the back coat layer was 1 to 30 g / m ² ,
20 g / m ^2, it is appropriate 5 to 20 g / m ^2.

(Example) Production Example 1 of Resin Particles A mixed solution of 95 g of dodecyl methacrylate, 5 g of acrylic acid and 200 g of toluene was heated to 70 ° C. while stirring under a nitrogen stream. 1.5 g of 2,2'-azobis (isobutyronitrile) (abbreviation: AIBN) was added thereto and reacted for 8 hours. 12 g of glycidyl methacrylate and t-
1 g of butylhydroquinone and 0.8 g of N, N-dimethyldodecylamine were added and reacted at 100 ° C. for 15 hours (dispersion resin [I]).

Next, 8.5 g of the above-mentioned dispersing resin (I) (as solid content),
A mixed solution of 40 g of the following monomer (M-1), 10 g of 2-cyanoethyl methacrylate and 250 g of n-heptane was heated to 60 ° C. while stirring under a nitrogen stream. 0.3 g of 2,2'-azobis (isovaleronitrile) (abbreviated as AIVN) was added and reacted for 6 hours.

Twenty minutes after the addition of the initiator (AIVN), the homogeneous solution became cloudy and the reaction temperature rose to 90 ° C. After cooling, a white dispersion was obtained through a 200-mesh nylon cloth. Average particle size 0.
It was 25 μm latex.

(Monomer M-1) Resin Particle Production Examples 2 to 13 Resin particles were produced in the same manner as in Production Example 1 except that the monomers shown in Table 2 below were used in place of Monomer M-1 in Production Example 1 for resin particles. did.

Production Example 14 of Resin Particles A mixed solution of 95 g of dodecyl methacrylate, 150 g of toluene and 50 g of isopropyl alcohol was heated to 70 ° C. while stirring under a nitrogen stream. In addition, 2,2'-azobis (4
5 g of (cyanovaleric acid) (abbreviation: ACV) was added and reacted for 8 hours. This mixed solution was reprecipitated in methanol 1.5, and the precipitate (resin) was dried at 40 ° C. under reduced pressure.

80 g of this resin, 10 g of glycidyl methacrylate, N, N-
A mixture of 0.7 g of dimethyldodecylamine, 1 g of t-butylhydroquinone and 200 g of toluene was heated to 95 ° C. and uniformly dissolved. The mixture was stirred for 48 hours as it was. The reaction product was reprecipitated in methanol 1.2, and the precipitate was dried at 30 ° C. under reduced pressure (dispersion resin [II]).

10 g of this dispersion resin [II], 50 g of the following monomer (M-14),
A mixture of 0.4 g of divinylbenzene and 280 g of n-octane was heated to 60 ° C. under a nitrogen stream to dissolve uniformly. 0.04 g of AIVN was added thereto and reacted for 5 hours to obtain a white dispersion. After cooling, the dispersion obtained through a 200-mesh nylon cloth had an average particle size of 0.25 μm.

(Monomer M-14) Resin particle production examples 15 to 23 The same as production example 14 except that in the production example 14 of the resin particles, the monomers of Table 3 below and the crosslinking monomer were used instead of the monomer M-1 and divinylbenzene. To produce resin particles.

Production Example 24 of Resin Particles 7.5 g of Dispersion Resin [II], 45 g of the following monomer M-20, 5 g of styrene, 1.0 g of divinylbenzene, and n-octane
The mixed solution of 300 g was heated to 50 ° C. under a nitrogen stream. 0.5 g (as solid content) of n-butyllithium was added thereto and reacted for 6 hours. The average particle size of the obtained white dispersion is
It was 0.15 μm.

(Monomer M-20) Production Example 25 of Resin Particles A solution obtained by mixing 20 g of monomer M-1, 0.5 g of diethylene glycol dimethacrylate, and 100 g of tetrahydrofuran was heated to 75 ° C. in a nitrogen stream. In addition, AIBN
0.2 g was added and reacted for 6 hours.

After cooling, the precipitate was reprecipitated in 500 ml of methanol, and the white matter was collected and dried. The yield was 15 g.

Example 1 40 g of butyl methacrylate, 30 g of 2-hydroxyethyl methacrylate, 4-cyanophenyl acrylate 3
After a mixed solution of 0 g and 200 g of toluene was heated to 75 ° C. under a nitrogen stream, 1.5 g of azobisisobutyronitrile was added and reacted for 8 hours. The weight average molecular weight of the obtained copolymer is 4100
It was 0.

Next, the above-mentioned copolymer is placed on an intermediate layer of a support in which a back layer is provided between one of the high-quality papers and an intermediate layer is provided on the other surface.
A dispersion obtained by subjecting a mixture of 40 g, 10 g of the resin particles of the present invention 1 (in terms of solid content), 100 g of zinc oxide and 300 g of toluene to a dispersion treatment for 2 hours in a ball mill was further added with 1,
After adding 3 g of 4-tetramethylene diisocyanate and dispersing and collecting for 10 minutes, apply with a wire bar so that the dry adhesion amount becomes 18 g / m ² and dry at 100 ° C for 2 hours to prepare a lithographic printing plate precursor. did.

The original plate was passed through an etching processor once with a desensitizing solution [ELP-EX manufactured by Fuji Photo Film Co., Ltd.], treated with 2 μm of distilled water, and mixed with the formed water. The contact angle measured by a goniometer was 10 °. In addition, before the desensitization treatment, it was 100 ° C. This indicates that the non-image portion of the image receiving layer of the original plate of the present invention has changed from lipophilic to hydrophilic (usually, the non-image portion does not generate printing background stain, dot stain, etc. during printing. The degree of conversion should be less than 20 ° in contact angle with water).

Next, plate making was performed using a commercially available PPC, and the resulting plate was subjected to a desensitizing treatment under the same conditions as described above to obtain a plate for printing.

The density of the image portion of the obtained original plate was 1.0 or more, there was no background fog in the non-image portion, and the image quality of the image portion was clear.
This was applied to an offset printing machine (Hamaduster 800SX, manufactured by Hamadastar Co., Ltd.) and printed on high quality paper. Even if the number of sheets exceeds 3,000, no problem occurs in the background smear of the non-image portion of the printed matter and the image quality of the image portion.

Furthermore, when the plate was made using a commercial PPC under the environmental conditions of 30 ° C. and 80% RH using the above-mentioned plate, the obtained plate image had an image density of 1.0 or more and had no background fog in the non-image area. And the image quality of the image part was clear. When this was printed in the same manner as above, there was no problem even when 3,000 sheets were printed.

As described above, the original plate did not deteriorate the image quality by the PPC plate making even under the condition of high temperature and high humidity.

Comparative Example a A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the comparative resin (R-1) having the following content was used in place of the particles of Production Example 1 of the resin particles. Created.

Comparative resin (R-1) A mixed solution of 40 g of monomer (M-1), 10 g of 2-cyanoethyl methacrylate and 100 g of tetrahydrofuran,
The mixture was heated to 60 ° C. while stirring under a nitrogen stream. Initiator AIV
0.5 g of N. was added and reacted for 4 hours, and 0.4 g of AIVN was further added and reacted for 4 hours to obtain a polymer solution containing 33.4% by weight of solids. The weight average molecular weight of the obtained polymer was 40,000 (a value obtained by a GPC method in terms of polystyrene).

Regarding the lithographic printing plate precursor of Comparative Example a obtained above,
Practical skill evaluation was performed in the same manner as in Example 1.

The contact angle with water before the desensitization treatment was 128 °, and the contact angle after the desensitization treatment was 20 to 30 °. The dispersion was large depending on the location, and the hydrophilicity was insufficient.

Further, when plate making and printing were actually performed in the same manner as in Example 1, the background stain due to the adhesion of the printing ink on the non-image portion occurred from the start of printing, and even after printing 3,000 sheets, the background stain was completely reduced. Did not.

This is because the resin corresponding to the resin particles of Production Example 1 (without using a dispersing resin) is dissolved in a solvent and is in a state of molecular dispersion similar to a so-called binder resin, as compared with the image receiving layer of the original plate of the present invention. When used, the resin (R-1) is also adsorbed and coated on the surface of the zinc oxide particles together with the binder resin, and the number of voids in the image receiving layer is reduced, so that when the desensitization is performed, The hydrophilic reaction on the surface of the zinc oxide particles is hindered, and a sufficient chemical reaction between the zinc oxide particles and the resin (R-1) can be achieved by a short-time chemical reaction treatment on the surface of the image receiving layer or inside the layer. It is presumed that it was hard to occur.

Examples 2 to 15 A lithographic printing plate precursor was prepared in the same manner as in Example 1, except that the resin particles in Table 4 below were used instead of the resin particles in Example 1.

When the contact angle with water, the image quality after PPC plate making, and the printing result were examined in the same manner as in Example 1, the image quality portion was good, and the printed material had no background fogging in the non-image portion, and the image portion did not. Clear image quality exceeded 3,000 sheets.

Example 16 As resin particles of the present invention, 150 g of a 15% aqueous solution of poly [N- (2-trimethylsilyloxoethyl methacrylate)], [n-butyl methacrylate / 4-cyanophenyl methacrylate (6/4) weight] Ratio] 20% emulsion aqueous solution of copolymer (weight average molecular weight 35,000) 30
0g, 10% aqueous solution of polynyl alcohol [PV from Kuraray Co., Ltd.
A-117] A dispersion obtained by dispersing a mixture of 200 g, 8 g of an 80% aqueous solution of melamine formaldehyde resin, and 400 g of a mixed dispersion of [zinc oxide / silica (2/8)] 20% for 1 hour in a ball mill. Using the same intermediate layer of the same support as in Example 1, apply it with a wire bar so that the dry adhesion amount becomes 8 g / cm ^2, and dry at 120 ° C. for 2 hours to prepare a lithographic printing plate precursor. did.

When processed and printed in the same manner as in Example 1, 3,000 or more printed materials were obtained in which the image portion of the printed material was clear and the non-image portion was free from background fog.

(Effects of the Invention) According to the present invention, it is possible to obtain a direct drawing type lithographic printing plate precursor having excellent suppression of generation of background stains and good printing durability.

Claims (2)

(57) [Claims] 1. A direct drawing type lithographic printing plate precursor having an image receiving layer on a support, wherein the image receiving layer has a particle size of 0.00.
An original plate for direct drawing type lithographic printing, comprising at least one resin particle having a size of 5 μm to 10 μm and containing at least one functional group which generates a hydroxyl group by decomposition. 2. A direct drawing type lithographic printing plate precursor having an image receiving layer on a support, wherein the image receiving layer has a particle size of 0.00.
5 to 10 μm, for direct drawing type lithographic printing, characterized by containing at least one kind of resin particles containing at least one kind of functional group which generates a hydroxyl group by decomposition and at least partially crosslinked. Original version.