JP3000687B2 - Waterless lithographic printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing plate for waterless lithographic printing capable of printing without using fountain solution, and particularly to waterless lithographic printing excellent in image characteristics such as halftone dot reproducibility. It is related to the original master.

[0002]

2. Description of the Related Art Waterless lithographic printing means that an image area and a non-image area are basically present on substantially the same plane, the image area is made ink-receptive, and the non-image area is made ink repellent. Utilizing the difference in the adhesiveness of the ink, the ink is applied only to the image area,
In lithographic printing, in which ink is transferred to a printing medium such as paper or film, the non-image area consists of a material layer having ink repellency, and means a printing plate that can be printed without using fountain solution. I do.

[0003] Such waterless planographic printing plates having practically excellent performance include those utilizing a silicone rubber layer as a material layer having ink repellency;
For example, positive waterless lithographic plates include JP-B-54-26923 and JP-B-56-23150.

These publications disclose that an acrylic resin can be used as a carrier resin for the photosensitive layer, and a polyurethane resin containing a polycondensed polyester diol as a polyol component. However, these resins are used as carrier resins for the photosensitive layer. The positive waterless lithographic plate used exhibited excellent image characteristics, but encountered poor reproducibility of the shadow part, but encountered some situations.

The inventors of the present invention have investigated the cause of such a decrease in the reproducibility of the shadow portion. As a result, the reproducibility of the shadow portion is reduced when the exposure frame temperature during exposure is relatively low, for example, 20%. The phenomenon that occurs easily when exposed at an exposure frame temperature of less than 100 ° C, and the phenomenon that the reproducibility of the shadow portion is inferior is that when the exposure frame temperature is low, the reaction rate of a monomer or the like in the photosensitive layer is reduced. As a result of finding out that the problem is caused by the above and further studying a solution thereof, the present invention has been achieved.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a waterless lithographic printing plate precursor having a wide latitude in exposure frame temperature, and particularly having excellent image characteristics even when the exposure frame temperature is low. .

[0007]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
A waterless planographic printing plate precursor in which a photosensitive layer and a silicone rubber layer are sequentially laminated on a support, wherein the carrier resin of the photosensitive layer contains a polyurethane resin containing polycaprolactone diol as a polyol component. Achieved by the master version.

The polyurethane resin used in the present invention is a polyurethane resin comprising a polyol component containing polycaprolactone diol, an isocyanate component, a chain extender and the like.

As the polycaprolactone diol which is an essential component of the polyurethane resin of the present invention, known polycaprolactone diols can be used. The polycaprolactone diol referred to here is an addition polymerization type polyester diol obtained by ring-opening polymerization of ε-caprolactam. Even if exposure printing frame temperature is low, the effect of improving the shadow section reproducibility,
From the viewpoint of Ru is more effectively exhibited, the number average molecular weight polycaprolactone diol 300 or more, to 5,000 or less
Ru Der thing of that. More preferably 500 or more, 3000
It is as follows. When the number average molecular weight is 300 or less,
When the light layer becomes hard and the exposure flame temperature is low, the shadow part reproducibility
Decrease. If the value is more than 5000, the sensitivity will decrease and the exposure will occur.
The time becomes longer and the workability decreases.

[0010] The polycaprolactone diol may be combined with other diol components. Other diol components may be known ones. For example, as the polymer diol,
Malonic, succinic, glutaric, adipic , azella
Ynoic acid, saturated aliphatic dicarboxylic acids such as sebacic acid, off
Unsaturated fatty acids such as malic acid, maleic acid, itaconic acid, etc.
Carboxylic acid, or phthalic acid , terephthalic acid, isophthalic acid
Aromatic dicarboxylic acids such as luic acid and naphthalic acid and ethylene glycol, diethylene glycol, triethylene glycol
Coal, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol
And diols such as polypropylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, bis (hydroxymethyl) cyclohexane, bis (hydroxyethyl) benzene, and polycaprolactone diol. And polyester diols obtained from the polycondensation reaction with In addition, hydroxyl groups are used for polyether diol, polyether ester diol, polybutadiene diol, and acrylic polymer.
Acrylic diol, polycarbonate diol , partially saponified ethylene-vinyl acetate copolymer,
Examples thereof include phosphorus diol and halogen-containing diol .
Low molecular weight diols include ethylene glycol and diethyl
Glycol, triethylene glycol, polyethylene
Glycol, propylene glycol, di propylene glycol
Coal, tripropylene glycol, polypropylene
Examples thereof include recol , 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, bis (hydroxymethyl) cyclohexane, and bis (hydroxyethyl) benzene. Further, two or more of these may be used in combination. Even when the exposure frame temperature is low, the polycaprolactone diol in the polyol component is at least 10% by weight, preferably at least 20% by weight, in order to more effectively exhibit the effect of improving the reproducibility of the shadow portion. Used.

The isocyanate component used in the polyurethane resin of the present invention may be a known one, such as tolylene diisocyanate, tolidine diisocyanate, or the like.
Monomers or modified products such as 4,4'-diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexyl methane diisocyanate, and isophorone diisocyanate Is raised. Further, two or more of these may be used in combination.

The chain extender may be a known one, for example , water, alcohol, diamine having the active hydrogen ,
The used diol is used. Ethylene as diamine
Diamine, 1,4-tetramethylenediamine, 1,6-
Hexamethylenediamine, p-xylylenediamine,
1,4-diaminocyclohexane, p-phenylenediamine, bis (4-aminocyclohexyl) methane, 1,
2-diaminopropane, 2,3-diaminobutane, piperazine, 4,4'-diamino-diphenylmethane, 4,
4'-diamino-diphenyl ether, trimethylene glycol-di-p-aminobenzoate, 4,4'-
3,3'-diamino-dichloro-diphenylmethane and the like. Further, two or more of these may be used in combination.

The photosensitive layer used in the present invention includes, for example, the following. A photosensitive layer composed of a carrier resin, an ethylenically unsaturated monomer, and a photopolymerization initiator. Polyurethane resin is used as the carrier resin, but may be used in combination with other resins. Such resins include polyester, polystyrene, polyamide, polyether, poly (meth) acrylate, polybutadiene, and the like. From the viewpoint of the effect of improving the reproducibility of the shadow portion when the exposure frame temperature is low, the proportion of the polyurethane resin in the carrier resin is preferably 10% by weight or more, more preferably 30% by weight or more.

Examples of the ethylenically unsaturated monomers include (meth) acrylic acid and its esters, (meth) acrylic amides, styrenes, maleic acid and its esters, and the like. Of these, the following are preferred.

(A) Esters of (meth) acrylic acid with the following alcohols. (Poly) ethylene glycol, (poly) propylene glycol, glycerol, sorbitol, trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol and the like. (B) Addition reaction products of glycidyl (meth) acrylate with the following amines and carboxylic acids having active hydrogen. (Mono, di or tri) ethanolamine, ethylenediamine, benzylamine, xylylenediamine, malonic acid, tartaric acid, maleic acid, succinic acid, etc. (C) Addition reaction products of (meth) acrylic acid with the following glycidyl esters. Glycidyl esters such as phthalic acid, tetrahydrophthalic acid, succinic acid, maleic acid, fumaric acid, and itaconic acid.

As the photopolymerization initiator, benzophenone derivatives, benzoin derivatives, anthraquinone derivatives, aldehydes, ketones, sulfur compounds, halogen compounds, or dyes such as methylene blue and riboflavin can be used.

And the photo-dimerizable unsaturated monomers such as cinnamic esters.

A combination of the carrier resin exemplified in the above, a compound having an epoxy group, and the following diazonium salt.

As the diazonium salt, a complex salt of the general formula (1), for example, 2,5-diethoxy-4- (p-toluylthio) benzenediazonium hexafluorophosphate is used.

[0020]

Embedded image

Combinations of the carrier resin exemplified in the above, a compound having an unsaturated bond such as an allyl group, and a compound having a thiol group.

Of the structures of these photosensitive layers, those preferably used. As for the photosensitive layer composition, the carrier resin is 3
0 to 80 parts by weight, 20 to 7 ethylenically unsaturated monomers
What is comprised by 0 weight part and a photoinitiator by 0.5-20 weight part is used preferably.

The thickness of the photosensitive layer is 0.1 to 100 μm, preferably 0.5 to 10 μm. Other components such as stabilizers, fillers, and dyes can be added to the photosensitive layer as long as the effects of the present invention are not impaired.

The silicone rubber layer used in the present invention comprises:
It is obtained by rubberizing a linear organic polysiloxane having a molecular weight of several thousand to several hundred thousand shown by the general formula (2) by crosslinking.

[0025]

Embedded image

Here, n is an integer of 1 or more, and R1 and R2 are a hydrogen atom, a vinyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an aminoalkyl group, a mercaptoalkyl group,
Haloalkyl group, hydroxyalkyl group, having 2 to 1 carbon atoms
A carboxyalkyl group of 0, a cyanoalkyl group, an optionally substituted aryl group having 6 to 20 carbon atoms, or
Aralkyl groups, which may be the same or different. As a crosslinking method, a method of crosslinking an alkyl group of a polysiloxane using a peroxide, a group capable of hydrolyzing a silanol-terminated polysiloxane (acetoxy group, alkoxy group, ketoxime group, etc.)
And a method utilizing an addition reaction between vinylsilyl and hydrosilyl, and the like. The thickness of the silicone rubber layer is 0.5 to 10
0 μm, preferably 0.5 to 10 μm, more preferably 0.5 to 5.0 μm.

As the support used in the present invention, any support may be used as long as it is used in a normal waterless planographic printing plate. For example, aluminum,
Examples thereof include metal plates such as copper, zinc, and steel, plastic films such as polyester, and coated paper.

It is also possible to further coat a primer layer on the support for the purpose of improving adhesiveness, plate inspection, and other purposes, and use it as a support. As the primer layer, an epoxy resin, a urea resin, a benzoguanamine resin, a melamine resin, a polyester resin, or the like is used alone or in combination.

For the purpose of protecting the silicone rubber layer forming the surface of the waterless planographic printing plate constituted as described above, a protective film is laminated on the surface of the silicone rubber layer or a thin plastic sheet is formed. The protective layer can be provided by coating or transferring.

[0030]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Example 1 The following photosensitive layer composition was applied on a 0.3 mm-thick aluminum plate (manufactured by Sumitomo Light Metal Co., Ltd.) using a bar coater.
It was dried in hot air at 10 ° C. for 1 minute to form a photosensitive layer having a thickness of 4 μm.

Polyurethane resin Polyurethane resin composed of polyol component; polycaprolactone diol (number average molecular weight 2000) isocyanate component; isophorone diisocyanate diamine component; 1,4-diaminocyclohexane
50 parts by weight Addition product of 4 moles of glycidyl methacrylate and 1 mole of xylylenediamine 41 parts by weight 4,4'-bis (diethylamino) benzophenone 5.5 parts by weight N-methylacridone
3 parts by weight crystal violet
0.5 parts by weight N, N-dimethylformamide
500 parts by weight Subsequently, a silicone gum composition having the following composition was applied on the photosensitive layer and dried to form a silicone rubber layer having a thickness of 3 μm.

100 parts by weight of polydimethylsiloxane having silanol groups at both ends (number average molecular weight 20,000) ethyltriacetoxysilane
8 parts by weight dibutyltin diacetate
0.2 parts by weight n-heptane
1200 parts by weight A 12 μm-thick polyethylene terephthalate film “Lumirror” (manufactured by Toray Industries, Inc.) was laminated as a cover film on a laminate obtained as described above using a calendar roller to obtain a waterless lithographic printing plate precursor. Obtained.

A positive film having a halftone dot image having 1% of a shadow portion and a highlight portion at 150 lines / inch in vacuum contact with the waterless planographic printing plate precursor, and a 45 Kw high-pressure mercury lamp at a distance of 1 m from a distance of 1 m. Exposure frame temperature is 30 seconds
Exposure was performed at 18 ° C and 18 ° C, respectively. The laminated film was removed from the exposed plate, and development was carried out by gently rubbing with a pad soaked with n-hexane.

At any exposure frame temperature, a halftone dot of 150 lines / inch and 1% shadow was completely reproduced.

Comparative Example 1 A waterless planographic printing plate having the same structure as in Example 1 was produced except that the polyurethane resin as the carrier resin in the photosensitive layer of Example 1 was changed to the following resin, and evaluated similarly. Then, the plate exposed at an exposure frame temperature of 30 ° C. was 150 lines /
Although the inch, 1% shadow halftone dots were completely reproduced, the plate exposed at 18 ° C. did not reproduce 150 lines / inch, 1% shadow halftone dots. Polyurethane resin Polyol component; Polyethylene adipate diol (number average molecular weight 2000) Isocyanate component; Isophorone diisocyanate Diamine component; 1,4-diaminocyclohexane Polyurethane resin Example 2 Polyurethane resin which is a carrier resin in the photosensitive layer of Example 1 A waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the following resin was changed to the following resin, and evaluated in the same manner.
C., 18 ° C.), the halftone dot of 150 lines / inch and 1% was completely reproduced. Polyurethane resin Polyol component; Polycaprolactone diol (number average molecular weight 1000) / polyethylene adipate diol (number average molecular weight 1500) = 3/1 Isocyanate component; Xylylene diisocyanate Diamine component; Polyurethane composed of bis (4-aminocyclohexyl) methane resin

[0037]

Since the present invention is constructed as described above, a waterless planographic printing plate having a wide exposure flame temperature latitude and excellent image characteristics can be reliably obtained.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (1)

(57) [Claims] 1. A waterless lithographic printing plate precursor in which a photosensitive layer and a silicone rubber layer are successively laminated on a support, wherein the simple resin of the photosensitive layer has a number average molecular weight of 300 as a polyol component.
A waterless lithographic printing plate precursor comprising a polyurethane resin containing 5,000 to 5,000 polycaprolactone diol.