JP2000131830A - Heat mode sensitive image forming element for manufacture of positive working printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat mode image forming element for the manufacture of a planographic printing plate having a wide development latitude, high resolution and improved vertical conveyability. SOLUTION: The heat mode image forming element has a 1st layer containing a polymer soluble in an aqueous alkaline solution on a planographic printing base having a hydrophilic surface and a top layer on the 1st layer side of the base. The top layer is sensitive to IR and impermeable to an alkaline developer. The 1st layer and the top layer may be formed as one layer. The top layer contains a compound that enhances the coefficient of dynamic friction of the top layer to 0.40-0.80.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates to heat mode imaging elements for making lithographic printing plates containing an IR sensitive top layer. More specifically, the present invention relates to heat mode imaging elements for making lithographic printing plates with better vertical transport.

[0002]

BACKGROUND OF THE INVENTION Lithographic printing is a method of printing from a specially made surface in which some areas can receive lithographic printing ink, while others do not receive the ink when wetted with water. It is. The areas that receive ink form the printed image areas and the ink-repellent areas form the background areas.

In the field of photolithographic printing, photographic materials are image-wise oily or greasy on a hydrophilic background, in exposed areas (negative-working) or in unexposed areas (positive-working). Receptive to ink.

[0004] Surface lithographic printing plate (surface lit)
ho plates) or planographic printing plates (pl
ananographic printing plate
In the preparation of conventional lithographic printing plates, also referred to as s), a thin layer of the photosensitive composition is coated on a support that has an affinity for water or obtains such an affinity by chemical treatment. Coatings for that purpose include photopolymer layers containing diazo compounds, dichromate-sensitized hydrophilic colloids and various synthetic photopolymers. In particular, diazo-sensitized systems are widely used.

When the photosensitive layer is image-wise exposed, the exposed image areas become insoluble and the non-exposed areas remain soluble. The plate is then developed using a suitable solution to remove the diazonium salt or diazo resin in unexposed areas.

[0006] In another case, printing plates are known that contain a photosensitive coating that is made soluble in the exposed areas when exposed image-wise. In that case, subsequent development removes the exposed areas. A typical example of such a photosensitive coating is a quinone-diazide based coating.

Typically, the photographic material from which the printing plate is made is camera-exposed through a photographic film containing the image to be reproduced in a lithographic printing process. Such work practices are cumbersome and labor intensive. On the other hand, however, the printing plates thus obtained are of excellent lithographic quality.

Thus, attempts have been made to obtain printing plates directly from computer data representing the image to be reproduced, except for the need for photographic film in the above method. However, the photosensitive coating is not sensitive enough to be directly exposed using a laser. It has therefore been proposed to coat a silver halide layer over the photosensitive coating. The silver halide can then be directly exposed using a laser under computer control. The silver halide layer is subsequently developed to leave a silver image on the photosensitive coating. The silver image then serves as a mask in the overall exposure of the photosensitive coating. After overall exposure, the silver image is removed and the photosensitive coating is developed. Such a method is described, for example, in JP-A-60.
Although it is disclosed in US Pat. No. 6,617,52, it has the disadvantage of requiring complex development and an associated developer.

GB-1 492 070 discloses a method of providing a metal layer or a layer containing carbon black on a photosensitive coating. Next, the metal layer is ablated using a laser to obtain an image mask on the photosensitive layer. The photosensitive layer is then entirely exposed by UV-light through an image mask. After removing the image mask, the photosensitive layer is developed to obtain a printing plate. However, this method still has the disadvantage that the image mask must be removed by a cumbersome process before developing the photosensitive layer.

[0010] In addition, methods are known for making printing plates that involve the use of imaging elements that are heat-sensitive rather than light-sensitive. A particular disadvantage of the photosensitive imaging element as described above for the preparation of a printing plate is that it must be shielded from light. Furthermore, they have sensitivity problems in terms of storage stability, and they exhibit relatively low resolution. There is a clear trend in the market towards heat mode printing plate precursors.

For example, Research in January 1992
Disclosure no. No. 33303 discloses a heat mode imaging element comprising on a support a crosslinked hydrophilic layer containing thermoplastic polymer particles and an infrared absorbing pigment such as carbon black. Imagewise exposure to the infrared laser causes the thermoplastic polymer particles to coagulate imagewise, thereby rendering the surface of the imaging element ink-receptive in these areas without further development. A disadvantage of this method is that the resulting printing plate is easily damaged, since the non-printed areas can become ink-receptive if some pressure is applied thereto. Furthermore, under marginal conditions, the lithographic performance of such printing plates can be poor, and thus such printing plates have little lithographic latitude.

US-P-4 708 925 discloses an imaging element comprising a photosensitive composition containing an alkali-soluble novolak resin and an onium-salt. The composition may optionally contain an IR-sensitizer. After exposing the imaging element imagewise to UV-visible- or IR-rays and following a development step with an aqueous alkaline solution, a positive- or negative-working printing plate is obtained. The printing results of the lithographic printing plate obtained by irradiation and development of the imaging element are inferior.

[0013] EP-A-625 728 discloses an imaging element comprising a layer which is sensitive to UV- and IR-radiation and which can be positive or negative working. This layer is made of resole resin, novolak resin,
Includes potential Bronsted acids and IR-absorbing materials.
The printing results of the lithographic printing plate obtained by irradiation and development of the imaging element are inferior.

US-P-5 340 699 is EP-
Almost the same as A-625 728, but discloses a method for obtaining a negative working IR-laser recording imaging element. The IR-sensitive layer is a resole resin,
Includes novolak resins, latent Bronsted acids and IR-absorbing materials. The printing results of the lithographic printing plate obtained by irradiation and development of the imaging element are inferior.

Further, EP-A-678 380 discloses a method of providing a protective layer on a roughened metal support under a laser-ablationable surface layer. Upon image-wise exposure, the surface layer is completely ablated as well as some portions of the protective layer. The printing plate is then treated with a cleaning liquid to remove the remainder of the protective layer, thereby exposing the hydrophilic surface layer.

EP-A-823 327 discloses a positive photosensitive composition which exhibits a difference in solubility in an alkaline developer between exposed and unexposed parts, which induces a difference in solubility. (A) as an ingredient
It contains a light-to-heat conversion material and (b) a high molecular weight compound whose solubility in an alkali developer can be changed mainly by changes other than chemical changes.

EP-A-830 941 describes a recording medium containing (i) a light-to-heat converting substance capable of converting radiation into heat, and (ii) an oleophobic compound on a flexible support having a lipophilic surface. A heat mode recording material having a surface layer, wherein the oleophobic surface layer and the recording layer can be the same layer, wherein the material has a coefficient of kinetic friction of 2.6 or less on the other side of the material. A heat mode recording material is disclosed.

FR-A-1 561 957 discloses a method for recording or reproducing information, comprising exposing a recording material sensitive to electromagnetic radiation under a form of information, The recording material includes a binder and at least one recording layer containing a liquid and / or solid dispersed in the binder, wherein the liquid and / or solid is more hydrophobic than the binder, When formed, a compatible mixture is formed at least partially with the binder, the mixture having a higher light transparency than the dispersion before heating, and the recording material also contains a compound capable of converting light to heat. In.

EP-A-97 200 588.8 describes
An interlayer comprising a polymer soluble in an aqueous alkaline solution and a top layer sensitive to IR radiation on a lithographic base having a hydrophilic surface, wherein the top layer is exposed to IR radiation when exposed to an aqueous alkaline solution. Disclose heat mode imaging elements for making lithographic printing plates wherein the volume permeated and / or solubilized is reduced or increased.

EP-A-97 203 129.8 and EP-A-97 203 132.2 disclose a heat mode imaging element consisting of a lithographic base having a hydrophilic surface and a top layer, the the top layer is sensitive to IR- line comprises a polymer soluble in aqueous alkaline solutions, a non-permeable with respect to an alkaline developer containing SiO ₂ as silicate.

The last three heat mode imaging elements have the disadvantage that their vertical transportability is not perfect in manufacturing, production, in imaging equipment, in processors and in other plate handling equipment. A solution to the problem will be valued.

[0022]

It is an object of the present invention to provide a wide development latitude (l).
It is to provide a heat mode imaging element for the preparation of a lithographic printing plate having an attitude.

It is an object of the present invention to provide a heat mode imaging element for making a lithographic printing plate having a high resolution.

It is a further object of the present invention to provide a heat mode imaging element for making a lithographic printing plate having improved vertical transport.

Further objects of the present invention will become clear from the description hereinafter.

[0026]

SUMMARY OF THE INVENTION In accordance with the present invention, a first layer containing a polymer soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer are provided on a lithographic base having a hydrophilic surface. A top layer, the top layer of which is IR-sensitive and impermeable to an alkaline developer, wherein said first layer and said top layer can be one and the same layer for making a lithographic printing plate. A heat mode imaging element; wherein the top layer has a kinetic coefficient of friction of the top layer of 0.40-0.
A heat mode imaging element is provided, which contains a compound that improves to 80.

[0027]

DETAILED DESCRIPTION OF THE INVENTION The top layer is also called the second layer.

Dynamic friction coefficient (dynamic or ki)
netic coefficient of fric
(μ _k ) is measured according to standard ASTM D1894, whereby the heat mode recording material is placed such that the front side of the material is in contact with stainless steel. Front side means the side of the material that carries the top layer with respect to the flexible support.

Suitable compounds which can be used to increase the coefficient of kinetic friction to 0.40 to 0.80 are polytetrafluoroethylene-polyethylene copolymers. Other suitable compounds are water-insoluble inorganic compounds having a three-dimensional structure in which the siloxane bonds extend three-dimensionally and the silicon atom is bonded to one organic group, such as a methyl group. The latter substance is known as TOSPEARL ^™ (Tosh
iba, Japan). Other suitable compounds are hydrophobic ceramics, barium sulphate and silicon-matte particles which are mixed with silica particles, preferably supplemental silica particles or orthosilicate. The average diameter of the particles is preferably in the range from 0.3 μm to 50 μm. The compound is preferably 10~800mg / m ^2, more preferably 20
Used in an amount of ４００400 mg / m ² .

In the case of the first embodiment, the first layer and the top layer are different. In this embodiment, a lithographic base having a hydrophilic surface has a first layer comprising a polymer soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic base as the first layer, The top layer provides a heat mode imaging element for making a lithographic printing plate that is sensitive to IR radiation and is impervious to alkaline developers.

The top layer according to the invention comprises an IR-dye or pigment and a binder resin. Mixtures of IR-dyes or pigments can be used, but it is preferred to use only one type of IR-dye or pigment. Preferably said I
The R-dye is an IR-cyanine dye. Particularly useful IR
The cyanine dye is a cyanine dye having at least two acid groups, more preferably at least two sulfone groups. Even more preferred are cyanine dyes having two indolenines and at least two sulfonic acid groups. Most preferred are compounds I having the structure
It is.

[0032]

Embedded image Particularly useful IR-absorbing pigments are carbon black, metal carbides, borides, nitrides, carbonitrides, bronze-
Structurally related to structural oxides and bronze groups,
An oxide having no component, for example, WO2.9. Conductive polymer dispersions, such as those based on polypyrrole or polyaniline, can also be used. The lithographic performance obtained, and especially the printing durability, depends on the heat sensitivity of the imaging element. In this regard, it has been found that carbon black gives very good and favorable results.

The IR-absorbing dye or pigment is preferably present in an amount of 1 to 99 parts by weight, more preferably 50 to 95 parts by weight of the total amount of said IR-sensitive top layer.

The top layer can preferably contain as binder a water-insoluble polymer such as a cellulose ester, a copolymer of vinylidene chloride and acrylonitrile, poly (meth) acrylate, polyvinyl chloride, a silicone resin and the like. Preferred as a binder is a nitrocellulose resin.

The total amount of the uppermost layer is preferably 0.05 to 1
0 g / m ^2, more preferably in the range of 0.1-2 g / m ^2.

When exposed image-wise, in the top layer, differences in the volume permeated and / or solubilized by the aqueous alkaline solution are created for the alkaline developers of the present invention.

In the present invention, image-wise IR exposure cleans the imaged portions without solubilizing and / or damaging the non-imaged portions during development. The capacity increases to the extent.

The development with the aqueous alkaline solution preferably takes place within an interval of 5 to 120 seconds.

The present invention preferentially between the top layer and the lithographic base is 7.5-14.
First soluble in an aqueous alkaline developer having a pH of
Including layers. The layer is preferably continuous with the top layer,
Other layers can be present between the top layer and the first layer.
The alkali-soluble binders used in this layer are preferably hydrophobic binders such as those used in conventional positive- or negative-acting PS-plates, such as novolak polymers, polymers containing hydroxystyrene units,
And carboxy-substituted polymers. Typical examples of these polymers are DE-A-4 007 428, DE-A
-4 027 301 and DE-A-4445 820
It is described in. The hydrophobic binders used in connection with the present invention are further characterized by insolubility in water and partial solubility / swellability in alkaline solutions and / or partial solubility in water when combined with cosolvents. I have.

Further, the alkali aqueous solution-soluble layer is preferably a visible light- and UV-light desensitizing layer. The layer is preferably thermally curable. The preferably visible- and UV-desensitized layers comprise photosensitive components that absorb in the wavelength range from 250 nm to 650 nm, such as diazo compounds, photoacids, photoinitiators, quinonediazides, sensitizers. Does not contain any agents. In this way, a printing plate stable in daylight can be obtained.

The first layer is preferably a low molecular weight acid, preferably a carboxylic acid, even more preferably benzoic acid.
Most preferably, it also contains 3,4,5-trimethoxybenzoic acid or benzophenone.

The ratio of the total amount of low molecular weight acid or benzophenone to polymer in the first layer is preferably 2:98.
-40: 60, more preferably 5: 95-20: 80. The total amount of the first layer is preferably 0.1 to 1
0 g / m ^2, more preferably from 0.3 to 2 g / m ^2.

In the imaging element of the present invention, the lithographic base for all embodiments can be anodized aluminum. A particularly preferred lithographic base is an electrochemically roughened, anodized aluminum support. The anodized aluminum support can be treated to increase its surface hydrophilicity. For example, an aluminum support can be silicated by treating its surface with a sodium silicate solution at an elevated temperature, for example, 95 ° C. In another case, a phosphating can be performed, which comprises treating the aluminum oxide surface with a phosphating solution,
The phosphate solution may further contain an inorganic fluoride. Further, the aluminum oxide surface can be rinsed with a citric acid or citrate solution. This treatment can be performed at room temperature or at a slightly elevated temperature of about 30-50 ° C. A further interesting treatment involves rinsing the aluminum oxide surface with a bicarbonate solution. In addition, polyvinyl phosphonic acid, polyvinyl methyl phosphonic acid, polyvinyl alcohol, phosphate ester of polyvinyl alcohol, polyvinyl sulfonic acid, polyvinyl benzene sulfonic acid, polyvinyl alcohol formed by reaction with sulfate ester of sulfonated aliphatic alcohol and sulfonated aliphatic aldehyde. It can be processed using acetal. It is further apparent that one or more of these post-treatments can be performed alone or in combination. A more detailed description of these processes is given in GB-A-1 084 070, DE-A-44.
23 140, DE-A-4417 907, EP-A
−659 909, EP-A-537 633, DE−
A-4001 466, EP-A-292 801;
EP-A-291 760 and US-P-4 458
005.

According to another mode in connection with the present invention, a lithographic base having a hydrophilic surface is, in all embodiments, a flexible support, such as paper or plastic provided with a cross-linked hydrophilic layer. Including film. Particularly suitable cross-linked hydrophilic layers can be obtained from hydrophilic binders cross-linked with cross-linking agents such as formaldehyde, glyoxal, polyisocyanate or hydrolyzed tetra-alkyl orthosilicate. The latter is particularly preferred.

As the hydrophilic binder, hydrophilic (co) polymers such as vinyl alcohol, acrylamide, methylolacrylamide, methylolmethacrylamide, acrylate acid, methacrylate acid,
Homopolymers and copolymers of hydroxyethyl acrylate and hydroxyethyl methacrylate or maleic anhydride / vinyl methyl ether copolymer can be used. The hydrophilicity of the (co) polymer or (co) polymer mixture used is preferably the same or higher than that of the polyvinyl acetate hydrolyzed to at least 60% by weight, preferably to the extent of 80% by weight.

The amount of crosslinker, especially tetraalkyl orthosilicate, is preferably at least 0.2 parts by weight, more preferably 0.5 to 5 parts by weight, most preferably 1.0 part by weight per part by weight of hydrophilic binder. ３3 parts by weight.

The lithographic base crosslinked hydrophilic layer used in accordance with this embodiment preferably also contains substances that enhance the mechanical strength and porosity of the layer. Colloidal silica can be used for this purpose. The colloidal silica used can be in the form of any commercially available water-dispersion of colloidal silica having, for example, an average particle size of up to 40 nm, for example 20 nm. In addition, inert particles of larger dimensions than colloidal silica, for example J.I.
Colloid and InterfaceSc
i. , Vol. 26, 1968, pages 62 t
o at least one of silica or alumina particles or particles of titanium dioxide or other heavy metal oxides prepared according to StOEber as described in 69.
Particles having an average diameter of 00 nm can be added. The introduction of these particles gives the surface of the cross-linked hydrophilic layer a uniform rough texture consisting of microscopic hills and valleys, which serves as a storage for water in the background areas.

The thickness of the lithographic base crosslinked hydrophilic layer according to this embodiment can vary within the range of 0.2 to 25 μm, preferably 1 to 10 μm.

A specific example of a cross-linked hydrophilic layer suitable for use in accordance with the present invention is described in EP-A-601 24
0, GB-P-1 419 512, FR-P-23
00354, US-P-3 971 660, US-P
-4 284 705 and EP-A 514 490.

As the lithographic printing base flexible support relating to this embodiment, a plastic film such as a substrate-based polyethylene terephthalate film, a substrate-based polyethylene naphthalate film, a cellulose acetate film, a polystyrene film, a polycarbonate film and the like can be used. Particularly preferred. The plastic film support can be opaque or transparent.

It is particularly preferable to use a polyester film support provided with an adhesion promoting layer. Particularly suitable adhesion promoting layers for use in accordance with the present invention are EP-A-619.
524, EP-A-620 502 and EP-A-6
A hydrophilic binder and colloidal silica as disclosed in US Pat. Preferably the amount of silica in the adhesion improving layer is between ^{200mg / m 2 ~750mg / m 2} . Furthermore, the ratio of silica to hydrophilic binder is preferably higher than 1, and the surface area of the colloidal silica is preferably at least 3
00 m ² / g, more preferably at least 500 m ² / g
It is.

In the second embodiment, the first and second layers are the same. In this embodiment, a lithographic printing plate having a top layer comprising a polymer sensitive to IR radiation and soluble in an aqueous alkaline solution, and impermeable to an alkaline developer, on a lithographic printing base having a hydrophilic surface. A heat mode imaging element for making a plate is provided.

The IR-sensitive layer according to the invention comprises an IR-dye or pigment and a polymer soluble in an aqueous alkaline solution. Mixtures of IR-dyes or pigments can be used, but it is preferred to use only one type of IR-dye or pigment. Suitable IR-dyes and pigments are those listed above in the first embodiment of the present invention.

The IR-dye is preferably 1 to 60 parts by weight, more preferably 3 to 5 parts by weight of the total amount of said IR-sensitive top layer.
It is present in an amount of 0 parts by weight.

The alkali-soluble polymers used in this layer are preferably hydrophobic and ink-receptive polymers such as those used in conventional positive- or negative-acting PS-plates, such as carboxy-substituted polymers. More preferred are phenolic resins, for example polymers containing hydroxystyrene units or novolak polymers. Most preferred are novolak polymers.
Typical examples of these polymers are DE-A-4 007
428, DE-A-4 027 301 and DE-A-
4 445 820. The hydrophobic polymers used in connection with the present invention are further characterized by insolubility in water and at least partial solubility / swelling in alkaline solutions and / or at least partial solubility in water when combined with cosolvents. And

Furthermore, the IR-sensitive layer is preferably a visible- and UV-light desensitizing layer. Furthermore, the layer is preferably thermally curable. This preferably visible light-and U
The V-photodesensitized layer does not contain photosensitive components that absorb in the wavelength range of 250 nm to 650 nm, such as diazo compounds, photoacids, photoinitiators, quinonediazides, sensitizers, and the like. In this way, a printing plate stable in daylight can be obtained.

The IR-sensitive layer is preferably a low molecular weight acid, preferably a carboxylic acid, even more preferably benzoic acid, most preferably 3,4,5-trimethoxybenzoic acid or benzophenone, more preferably trihydroxybenzophenone. Including.

The ratio of the total amount of low molecular weight acid or benzophenone to polymer in the IR-sensitive layer is preferably from 2:98 to 40:60, more preferably from 5:95 to 3
The range is 0:70. The total amount of said IR-sensitive layer is preferably 0.1 to 10 g / m ² , more preferably 0.3
２2 g / m ² .

When image-wise exposed, differences in the volume permeated and / or solubilized by the alkaline developer in the IR-sensitive layer are created for the alkaline developer of the present invention.

To prepare a lithographic printing plate, the heat mode imaging element is imagewise exposed and developed.

Image-wise exposure in connection with the present invention is infrared or near-infrared, ie, an image-wise scanning exposure involving the use of a laser operating in the wavelength region of 700-1500 nm. Most preferred are laser diodes that emit in the near-infrared. Exposure of the imaging element can be performed using a laser having a short pixel dwell time as well as a laser having a long pixel dwell time. Preferred is 0.0
A laser with a pixel dwell time of between 05 μs and 20 μs.

After image-wise exposure, the heat mode imaging element is developed by rinsing it with an aqueous alkaline solution. The aqueous alkaline solution used in the present invention,
Used for the development of normal positive working presensitised printing plates, preferably containing SiO ₂ as silicates, preferably having a pH of from 11.5 to 14. The imaged portion of the top layer thus exposed and made more permeable to the aqueous alkaline solution is cleaned,
This gives a positive working printing plate.

In the case of the present invention, the composition of the developer used is also very important.

Therefore, what is particularly important for stable development for a long time is the quality such as the concentration of alkali and the concentration of silicate in the developer. Under such circumstances, the present inventors can carry out rapid high-temperature processing only when a developer having the above composition is used, the amount of replenisher to be supplemented is small, and the developer must be replaced. It has been found that stable development can be carried out over a long period of three months or more without any problem.

Preferably, the developing solution used in the present invention and the replenisher for the developing solution are mainly alkali metal silicate and alkali metal hydroxide represented by MOH or M _2.
An aqueous solution containing its oxides, represented by O, wherein the developer is SiO ₂ and M ₂ in a molar ratio of 0.5 to 1.5.
O is contained, and the concentration of SiO ₂ is 0.5 to 5% by weight.
Suitable as such alkali metal silicates are, for example, sodium silicate, potassium silicate, lithium silicate and sodium metasilicate. On the other hand, preferred as such alkali metal hydroxides are sodium hydroxide, potassium hydroxide and lithium hydroxide.

The developer used in the present invention can simultaneously contain another alkaline reagent. Examples of such other alkaline reagents are ammonium hydroxide, sodium triphosphate, sodium diphosphate, potassium triphosphate, potassium diphosphate, ammonium triphosphate,
Inorganic alkaline reagents such as ammonium diphosphate, sodium bicarbonate, sodium carbonate, potassium carbonate and ammonium carbonate; and mono-, di- or triethanolamine, mono-, di- or trimethylamine, mono-, di- or triethylamine And organic alkaline reagents such as mono- or di-isopropylamine, n-butylamine, mono-, di- or triisopropanolamine, ethyleneimine, ethylenediimine and tetramethylammonium hydroxide.

In the case of the present invention, [SiO ₂ ] /
The molar ratio of [M ₂ O] is particularly important, it is generally 0.6 to 1.5, preferably from 0.7 to 1.3. This means that if the molar ratio is lower than 0.6, a large variation in activity is observed, whereas if it exceeds 1.5, rapid development becomes difficult, and the elution of the photosensitive layer on non-image areas or This is because the removal tends to be incomplete. Further concentration of SiO ₂ in the developer and replenisher preferably ranges from 1 to 4 wt%. Such limitation of the concentration of SiO ₂ makes it possible to provide large amounts of stable lithographic printing plates having good finishing qualities even when treated prolonged present invention.

In a particularly preferred embodiment, 1.0 to
A molar ratio [SiO 2 in the range of 1.5_Two] / [M_TwoO] and 1 to 1
4% by weight SiO_TwoMetal silicic acid having a concentration of
An aqueous salt solution is used as a developer. Such a place
Is equal to or higher than the alkali concentration of the developer
Of course, replenishers with alkaline concentrations are used
It is. To reduce the amount of replenisher to be supplied
In addition, the molar ratio of the replenisher [SiO _Two] / [M_TwoO] of the developer
Less than or equal to or developer
If the molar ratio of_TwoConcentration of
Is advantageously high.

In the developing solution and the replenisher used in the present invention, an organic solvent having a solubility in water at 20 ° C. of 10% by weight or less can be used simultaneously if necessary. Examples of such organic solvents are ethyl acetate, propyl acetate,
Carboxylic esters such as butyl acetate, amyl acetate, benzyl acetate, ethylene glycol monobutyl acetate, butyl lactate and butyl levulinate; ketones such as ethyl butyl ketone, methyl isobutyl ketone and cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol benzyl Ether, ethylene glycol monophenyl ether, benzyl alcohol,
Alcohols such as methylphenylcarbinol, n-amyl alcohol and methylamyl alcohol; alkyl-substituted aromatic hydrocarbons such as chilesin; and halogenated hydrocarbons such as methylene dichloride and monochlorobenzene. These organic solvents can be used alone or in combination. Particularly preferred in the present invention is benzyl alcohol. These organic solvents are generally added to the developer or replenisher therefor in amounts of up to 5% by weight, preferably up to 4% by weight.

The developer and replenisher used in the present invention can simultaneously contain a surfactant for the purpose of improving their developability. Examples of such surfactants include salts of higher alcohol (C8-C22) sulfates, such as sodium salt of lauryl alcohol sulfate,
Sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, TEE
POL B-81 ^™ (trademark, Shell Chemical)
als Co. And disodium alkyl sulfates; salts of aliphatic alcohol phosphates, such as sodium salt of cetyl alcohol phosphate; alkyl aryl sulfonates, such as sodium salt of dodecylbenzene sulfonate, isopropyl naphthalene sulfonate. Sodium salt, sodium salt of dinaphthalenedisulfonate and sodium salt of metanitrobenzene sulfonate; sulfonate of alkyl amide, for example, C ₁₇ H ₃₃ CON (CH ₃ ) CH ₂ CH
Includes ₂ SO ₃ Na and sulfonates of dibasic aliphatic acid esters, such as sodium dioctyl sulfosuccinate and sodium dihexyl sulfosuccinate. These surfactants can be used alone or in combination. Particularly preferred are sulfonates. These surfactants can generally be used in amounts of up to 5% by weight, preferably up to 3% by weight.

In order to enhance the development stability of the developer and replenisher used in the present invention, the following compounds can be used simultaneously.

Examples of such compounds are neutral salts such as J
N-A as disclosed in N-A-58-75 152
aCl, KCl and KBr; chelating agents such as JN
-A-58-190 952 (U.S.A.-4469)
776) EDTA and NT as disclosed in
A, JN-A-59-121 336 (US-A-46
[Co (N) as disclosed in US Pat.
H _{3) 6]} complex such as _{C1 3; JN-A-55-25} 1
IIa, I of the periodic table such as those disclosed in US Pat.
Ionizable compounds of group IIa or IIIb elements; anionic or amphoteric surfactants, for example JN-A-50-
Sodium alkylnaphthalenesulfonate and N-tetradecyl-N, N as disclosed in US Pat.
-Dihydroxytyl betaine; US-A-4 374
920; ionic surfactants as disclosed in JN-A-60-213 943; cationic polymers;
For example, the methyl chloride quaternary product of p-dimethylaminomethyl polystyrene as disclosed in JN-A-55-95946
amphoteric polyelectrolytes, such as copolymers of vinylbenzyltrimethylammonium chloride and sodium acrylate as disclosed in JN-A-56-142528; reducing inorganic salts, such as JN-A-57-192 952
Sodium sulfite and alkali-soluble mercapto compounds or thioether compounds such as disclosed in (US-A-4 467 027) such as thiosalicylic acid, cysteine and thioglycolic acid; inorganic lithium compounds such as JN-A-58-59. Lithium chloride as disclosed in US Pat. No. 444; organolithium compounds such as lithium benzoate as disclosed in JN-A-5034442; Si as disclosed in JN-A-59-75 255 Organometallic surfactants containing, Ti and the like; JN-A-59-84 241 (US-
A-4 500 625) organoboron compounds as disclosed in quaternary ammonium salts such as EP-A
Tetraalkylammonium oxides as disclosed in -101 010; and bactericides, for example sodium dehydroacetate as disclosed in JN-A-63-226657.

In the method for development processing of the present invention,
Any known means of replenishing the replenisher for the developer can be used. An example of such a method preferably used is JN-A-55-115039 (GB-A-
JN-A-58-953, a method for intermittent or continuous replenishment as a function of the amount and time of PS plates processed as disclosed in US Pat. No. 2,046,931).
A sensor for detecting the extent of the eluted photosensitive layer as described in US Pat. No. 49 (U.S. Pat. No. 4,537,496) is located in the central part of the development zone and is sensitive to the extent of the eluted photosensitive layer to be detected. A method comprising proportionally replenishing the replenisher; determining the impedance value of the developer solution as disclosed in GB-A-2 208 249, processing the detected impedance value by a computer and processing the replenisher solution It is a method that includes performing replenishment.

The printing plate of the present invention can be used as a seamless sleeve printing plate in a printing method. With this option, the printing plate is soldered in a cylindrical shape using a laser. Instead of applying a classically produced printing plate in a classical way, this cylindrical printing plate having the diameter of the printing cylinder as a diameter is slid over the printing cylinder. For more details on sleeves see "Grafisch Nieuws"
ed. Keesing, 15, 1995, page
4 to 6.

After the image-forming element exposed image-wise is developed using an aqueous alkaline solution and dried, the resulting plate can be used as it is as a printing plate. However, to improve the durability, the plate can be baked at a temperature of 200 ° C. to 300 ° C. for 30 seconds to 5 minutes. The imaging element can also be subjected to an overall post-exposure to UV-radiation to harden the image and increase the run length of the printing plate.

The following examples illustrate the present invention without limiting it thereto. All parts and percentages are by weight unless otherwise specified.

[0077]

EXAMPLES Comparative Example 1 Preparation of a lithographic printing base Aluminum foil 0.30 mm thick was submerged at 50 ° C. in an aqueous solution containing 5 g / l sodium hydroxide and rinsed with deionized water. Degreased. Then 3
Using alternating current at a temperature of 5 ° C. and a current density of 1200 A / m 2, 4 g / l hydrochloric acid, 4 g / l boric acid and 5 g / l
The foil was electrochemically roughened in an aqueous solution containing 1 aluminum ion to form a surface topology with an average centerline roughness Ra of 0.5 μm.

After rinsing with deionized water, then 300 g /
at 60 ° C. using an aqueous solution containing 1
The aluminum foil was etched for 0 seconds and rinsed with deionized water at 25 ° C. for 30 seconds.

The foil was then placed in an aqueous solution containing 200 g / l of sulfuric acid at a temperature of 45 ° C., a voltage of about 10 V and 150
Anodize at a current density of A / m ² for about 300 seconds to form an anodized film of 3.00 g / m ² Al ₂ O ₃ , then wash with deionized water and contain polyvinylphosphonic acid Work-up with the solution and subsequently with the solution containing aluminum trichloride, and with deionized water
Rinse at 0 ° C. for 120 seconds and dry. Preparation of Heat Mode Imaging Element On the lithographic base described above, initially 8.6 in a 55/45 ratio of tetrahydrofuran / methoxypropanol.
A layer from the wt% solution was coated at a wet coating thickness of 14 μm. The resulting layer is 88% ALNOV
OL SPN452 ^™ (Clariant, Germany)
novolak) and 12% 3,4
It contained 5-trimethoxybenzoic acid.

Then, on this layer was added 0.73 in methyl ethyl ketone / methoxypropanol in a 50/50 ratio.
An IR-sensitive layer was coated from a 4% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The IR-sensitive layer obtained was 115 mg / m
^TwoOf carbon black, 11.5mg / m^TwoNitrocell
Loin, 2.1 mg / m^TwoSOLSPERSE 50
00 ^TM(Zeneca Specialties, G
B), 11.3 mg / m^TwoSOLSPE
RSE 28000^TM, 2.0 mg / m^TwoTEGOW
ET 265^TM(Available from Tego, Germany
No) and 5.0 mg / m^TwoTEGO GIDE 4
10^TMWas contained.

Example 2 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from an 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 88% available layer
ALNOVOL SPN452 ^™ and 12% of 3,
It contained 4,5-trimethoxybenzoic acid.

This layer was then overlaid with 1.23 in 50/50 methyl ethyl ketone / methoxypropanol.
An IR-sensitive layer was coated from a 5% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The resulting IR-sensitive layer was 115 mg / m
^TwoOf carbon black, 100mg / m^TwoOf chemically manufactured
Silicon dioxide: AEROSIL^R200, 11.
5mg / m^TwoNitrocellulose, 2.1 mg / m^TwoS
OLSPERSE 5000 ^TM(Zeneca Spe
citizens, GB), 11.3 m
g / m^TwoSOLSPERSE 28000^TM, 2.0
mg / m^TwoTEGOWET 265^TM(Tego, G
ermany) and 5.0 mg / m^TwoT
EGO GLIDE 410^TMWas contained. AEROS
IL^RIs a product from Degussa, Germany
is there.

Example 3 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from an 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 88% available layer
ALNOVOL SPN452 ^™ and 12% of 3,
It contained 4,5-trimethoxybenzoic acid.

Then, on top of this layer, 1.73 in a 50/50 ratio of methyl ethyl ketone / methoxypropanol.
An IR-sensitive layer was coated from a 5% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The resulting IR-sensitive layer is 115 mg / m
² carbon black, 200 mg / m ² micronized poly (tetrafluoroethylene) modified polyethylene wax: NEWKEM TF320 ^™ , 11.5 mg / m
m ² nitrocellulose, of 2.1mg / m ² SOLSP
ERSE 5000 ^TM (Zeneca Special
items, available from GB), 11.3 mg / m ²
SOLSPERSE 28000 ^™ , 2.0 mg / m
² TEGO WET 265 ^TM (Tego, Germ
any 5.0) /5.0 mg / m ² TEGO
GLIDE 410 ^™ was included.

NEWKEM TF320 ^™ is available from Croda
Resins Ltd. Commercially available from.

Example 4 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from an 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 88% available layer
ALNOVOL SPN452 ^™ and 12% of 3,
It contained 4,5-trimethoxybenzoic acid.

The layer was then overlaid with 1.23 in 50/50 methyl ethyl ketone / methoxypropanol.
An IR-sensitive layer was coated from a 5% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The resulting IR-sensitive layer is 115 mg / m
^TwoOf carbon black, 100mg / m^TwoBarium sulfate
11.5mg / m^TwoNitrocellulose, 2.1m
g / m ^TwoSOLSPERSE 5000^TM(Zene
Available from ca Specialties, GB
No), 11.3 mg / m^TwoSOLSPERSE 28
000^TM, 2.0 mg / m^TwoTEGO WET 26
5^TM(Available from Tego, Germany) and
5.0mg / m^TwoTEGO GIDE 410^TMTo
Contained.

The barium sulfate used was S from Merck.
PEZIALSORTE A1 ^™ .

Example 5 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from a 9.3 wt% solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 82% available layer
ALNOVOL SPN452 ^™ and 11% of 3,
It contained 4,5-trimethoxybenzoic acid and 7% barium sulfate.

Then, on top of this layer was added 1.23 in a 50/50 ratio of methyl ethyl ketone / methoxypropanol.
An IR-sensitive layer was coated from a 5% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The IR-sensitive layer obtained is 115 mg / m
^TwoOf carbon black, 100mg / m^TwoBarium sulfate
11.5mg / m^TwoNitrocellulose, 2.1m
g / m ^TwoSOLSPERSE 5000^TM(Zene
Available from ca Specialties, GB
No), 11.3 mg / m^TwoSOLSPERSE 28
000^TM, 2.0 mg / m^TwoTEGO WET 26
5^TM(Available from Tego, Germany) and
5.0mg / m^TwoTEGO GIDE 410^TMTo
Contained.

Example 6 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from an 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 88% available layer
Alnovol SPN452 and 12% 3,4,5
-Contains trimethoxybenzoic acid. An IR-sensitive layer was then coated over this layer from a 1.235% by weight solution in methyl ethyl ketone / methoxypropanol in a 50/50 ratio with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The resulting IR-sensitive layer is 115 mg / m
^TwoOf carbon black, 100mg / m^TwoFine particles of silicon
: TOSPEARL 105^TM, 11.5mg / m
^TwoNitrocellulose, 2.1 mg / m^TwoSOLSPE
RSE 5000^TM(Zeneca Specialia
ties, available from GB), 11.3 mg / m ^Twoof
SOLSPERSE 28000^TM, 2.0 mg / m^Two
TEGO WET265^TM(Tego, German
y available) and 5.0 mg / m^TwoTEGO G
LIDE 410^TMWas contained.

TOSPEARL 105 ^TM is available from Toshi
ba Silicone Co. Ltd is a commercially available particulate silicone with an average particle size of 0.5 μm.

Example 7 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from an 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 88% available layer
ALNOVOL SPN452 ^™ and 12% of 3,
It contained 4,5-trimethoxybenzoic acid.

Then, on this layer was added 1.01 of a 50/50 ratio of methyl ethyl ketone / methoxypropanol.
An IR-sensitive layer was coated from a 2% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The IR-sensitive layer obtained is 115 mg / m
^TwoOf carbon black, 55mg / m^TwoSynthetic ceramic
C, 11.5mg / m^TwoNitrocellulose, 2.1m
g / m ^TwoSOLSPERSE 5000^TM(Zene
Available from ca Specialties, GB
No), 11.3 mg / m^TwoSOLSPERSE 28
000^TM, 2.0 mg / m^TwoTEGO WET 26
5^TM(Available from Tego, Germany) and
5.0mg / m^TwoTEGO GIDE 410^TMTo
Contained.

The synthetic ceramic was poly (methyl methacrylate-co-methyl methacrylate trimethoxysilane)
It is.

Example 8 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from an 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 88% available layer
ALNOVOL SPN452 ^™ and 12% of 3,
It contained 4,5-trimethoxybenzoic acid.

Then, a layer of 1.01 in methyl ethyl ketone / methoxypropanol in a 50/50 ratio was placed on top of this layer.
An IR-sensitive layer was coated from a 0% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The resulting IR-sensitive layer is 115 mg / m
² of carbon black, the same ceramic as mentioned in Example 7 of 44 mg / m ^2, of 11 mg / m ² AEROSIL ^R
200, 11.5 mg / m ² nitrocellulose;
1 mg / m ² SOLSPERSE 5000 ^™ (Ze
neca Specialties, GB), 11.3 mg / m ² SOLSPERSE 28
000 ^TM , 2.0 mg / m ² TEGO WET 26
5 ^™ (available from Tego, Germany) and 5.0 mg / m ² of TEGO GLIDE 410 ^™ .

Example 9 The same base as described in Comparative Example 1 was used. Preparation of Heat Mode Imaging Element On the lithographic base described in Example 1
A layer from an 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a ratio of 45 was coated with a wet coating thickness of 14 μm. 88% available layer
ALNOVOL SPN452 ^™ and 12% of 3,
It contained 4,5-trimethoxybenzoic acid.

Then, on top of this layer was added 1.01 in a 50/50 ratio of methyl ethyl ketone / methoxypropanol.
An IR-sensitive layer was coated from a 0% by weight solution with a wet coating thickness of 20 μm. This layer was dried at a temperature of 120 ° C.

The resulting IR-sensitive layer is 115 mg / m
² of carbon black, 39 mg / same ceramic as mentioned in Example 7 of m ^2, tetraethylorthosilicate 16 mg / m ^2, nitrocellulose 11.5mg / m ^2, SOLSPERSE 5000 of 2.1 mg / m ^2
TM (available from Zeneca Specialties, GB), 11.3 mg / m ² SOLSPERS
E 28000 ^™ , 2.0 mg / m ² TEGO WE
T265 ^™ (available from Tego, Germany) and 5.0 mg / m ² of TEGO GLIDE 4
10 ^TM . The tetraethyl orthosilicate used was DYNASIL from Huels AG

A was ^TM .

Measurement of Coefficient of Friction of Heat Mode Imaging Element The kinetic coefficient of friction against stainless steel was measured from the above materials according to ASTM D1894.

[0111]

[Table 1] Transportability test In the experimental apparatus, a 740 mm x 640 mm mold plate was transported over a length of 2 m to the laser drum. The plate was placed vertically and gripped between two steel clamps. To ensure stable transport, the clamp has a minimum length of about 20 cm. The contact width of these clamps with the plate is about 3 mm. The pressure on these clamps is 4.
It was set to 5 * 10 ⁵ Pa.

[0112]

[Table 2] In the case of Comparative Example 1, the plate did not reach the end position of the transport path in the correct way. Manual exposure of the laser drum was required to expose the plate. Exposure of Heat Mode Imaging Element All of the above materials were exposed at 2400 dpi using a Creo 3244T ^™ external drum plate setter.
Images were formed with the outputs shown in the table below.

[0113]

[Table 3] Development of the Imagewise Exposed Element After exposure of the manufactured imaging element, the element was developed in an aqueous alkaline developer. These developments are OZASOL
EP262A ^TM (OZASOL EP262A ^TM is A
gfa), and a Technigraph NPX-32 ^™ processor filled with water for the rinsing section and OZASOL RC795 ^™ rubber for the gumming section at 25 ° C. at a speed of 1 m / min.

All the resulting printing plates have intact images without etching defects. The main features and aspects of the present invention are as follows.

1. On a lithographic base having a hydrophilic surface, a first layer comprising a polymer soluble in an aqueous alkaline solution and a top layer on the same side as the first layer of the lithographic base, the top layer comprising IR- The first layer and the top layer being a heat mode imaging element for making a lithographic printing plate, which is sensitive and impermeable to an alkaline developer, which can be one and the same layer; A heat mode imaging element wherein the upper layer contains a compound which improves the kinetic friction coefficient of the uppermost layer to 0.40 to 0.80.

[0116] 2. 2. A heat mode imaging element for making a lithographic printing plate according to claim 1, wherein said compound is a polytetrafluoroethylene-polyethylene copolymer.

3. 2. A heat mode imaging element for making a lithographic printing plate according to claim 1, wherein said compound is silica.

4. 2. A heat mode imaging element for making a lithographic printing plate according to claim 1, wherein said compound is a hydrophobic ceramic.

5. 5. A heat mode imaging element for making a lithographic printing plate according to claim 4, wherein said top layer further contains silica particles.

6. 5. A heat mode imaging element for making a lithographic printing plate according to claim 4, wherein said top layer further contains an orthosilicate.

7. (1) the compound is barium sulfate;
A heat mode imaging element for making a lithographic printing plate as described in paragraph.

8. Heat mode imaging element for making a lithographic printing plate according to any one of the above 1 to 7, wherein said compound is present in the top layer in an amount of 10~800mg / m ^2.

9. a) exposing the heat mode imaging element according to any of the above paragraphs 1 to 8 imagewise to IR-radiation; b) using the imagewise exposed heat mode imaging element with an aqueous alkaline developer. And dissolving the exposed areas of the first and top layers, which can be the same, and leaving the unexposed areas of the first layer undissolved.

Continued on the front page (72) Inventor Peter Goeltz Belgium B 2640 Malt Cell Septes Trat 27 Agfa-Gevuert Na Mrose Fennoutjapp

Claims (2)

[Claims] 1. A lithographic printing base having a hydrophilic surface, comprising a first layer comprising a polymer soluble in an aqueous alkaline solution and a top layer on the same side of the lithographic printing base as the first layer. The top layer is IR-sensitive and impervious to alkaline developers, and the first layer and the top layer are heat mode imaging elements for making a lithographic printing plate that can be one and the same layer. A heat mode imaging element wherein the uppermost layer contains a compound that improves the kinetic friction coefficient of the uppermost layer to 0.40 to 0.80. 2. a) exposing the heat mode imaging element of claim 1 image-wise to IR-radiation; b) using the image mode exposed heat mode imaging element with an aqueous alkaline developer. And dissolving the exposed areas of the first and top layers, which can be the same, and leaving the unexposed areas of the first layer undissolved.