JP2000131831A - 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 capable of giving a planographic printing plate having superior printability by an easy method, capable of development by a selective, rapid, easy and ecological method and having high infrared sensitivity and a large difference in developability between exposed and unexposed regions. SOLUTION: The heat mode image forming element for the manufacture of a planographic printing plate 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 aqueous alkaline developer. At least one of the 1st layer and the top layer contains a surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates to heat mode imaging elements for making lithographic printing plates. More particularly, the present invention relates to a heat mode imaging element for making a lithographic printing plate in which the difference between the exposed and unexposed areas of the top layer that is permeated and / or solubilized by the aqueous developer is increased. .

[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.

[0003] In the field of photolithographic printing, photographic materials are image-wise on oily or greasy inks on a hydrophilic background, in exposed areas (negative-working) or in non-exposed areas (positive-working). Receptive.

[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 rendered soluble in 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.

GB-A-1 208 415 uses a heat sensitive recording layer constructed with an intermediate layer such that heating as information produces a recording of information as a difference in water-permeability in various areas of the recording layer. Alternatively, the recording material, including the support, which is retained without it, is heated as informed and penetrates through the water-permeable or relatively water-permeable areas of the recording layer, and Treating the recording material with an aqueous liquid configured to cause a permanent physical and / or chemical change of at least the surface portion of the support or the intermediate layer, and removing the entire recording layer by removing the entire recording layer A method of recording information is disclosed, including exposing an underlying support or interlayer that has been altered in an informational manner.

JP-A-01-46739 discloses that a photosensitive composition containing at least one photosensitive material, a fluorine surfactant and a defoamer is dissolved in a coating solvent, and then the solution is coated on a base. A method for preventing line-like unevenness caused by foam by drying the coating is disclosed.

JP-A-02-29750 is suitable for a positive photosensitive printing plate by using a non-ionic surfactant such as o-naphthoquinonediazidesulfonic acid, an alkali-soluble resin and polyoxyethylene naphthol. A method for obtaining a photosensitive composition is disclosed.

EP-A-527.369 discloses a photosensitive recording material comprising a support and a positive-working photosensitive layer having a rough surface, wherein the photosensitive layer comprises at least one 1,2 as a photosensitive compound. The photosensitive layer comprises a polycondensate or a polymer and a filler as a quinonediazide and a water-insoluble and water-alkaline solution-soluble or swellable binder, wherein the photosensitive layer is (i) filled at a layer weight of 3 g / m ² or less Agent with an average diameter of 3-5 μm and 15
Silica with a final limit of μm is treated with Be for 20-100 seconds.
ck, and (i)
i) It further contains a surfactant having a polysiloxane unit.

EP-A-823 327 discloses a positive photosensitive composition exhibiting a difference in solubility in an alkaline developer between exposed and unexposed parts, which is a component which induces a difference in solubility. It contains (a) 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.

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-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.

In the last heat mode imaging element, the difference in solubility between exposed and unexposed areas is not very large, and during processing of the element, the unexposed areas also dissolve and the plate becomes a lithographic printing plate. Has the disadvantage that it cannot be used as

[0023]

OBJECTS OF THE INVENTION It is an object of the present invention to provide a heat mode imaging element for making lithographic printing plates in a very simple manner.

Another object of the present invention is to provide a heat mode sensitive imaging element which can be developed in a selective, rapid, convenient and ecological way to produce positive lithographic printing with excellent printability. It is to provide.

It is a further object of the present invention to provide a heat mode sensitive imaging element having high infrared sensitivity.

It is also an object of the present invention to provide a heat mode sensitive imaging element having a large difference in developability in developer between exposed and unexposed areas.

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

[0028]

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 heat mode imaging element for making a lithographic printing plate having an upper layer, wherein the uppermost layer is IR-sensitive and impervious to aqueous alkaline developers; at least one of the first layer and the uppermost layer There is provided a heat mode imaging element, one of which comprises a surfactant.

[0029]

DETAILED DESCRIPTION OF THE INVENTION It has been found that a heat-sensitive imaging element according to the invention can be obtained in a simple manner, which gives a high quality lithographic printing plate.

[0030] The first and / or top (also referred to as second) layers include a surfactant. The surfactant can be a cationic, anionic or amphoteric surfactant, but is preferably a non-ionic surfactant. The surfactant is preferably selected from the group consisting of a perfluoroalkyl surfactant, an alkylphenyl surfactant, and most preferably a polysiloxane surfactant. Even more preferably, a combination of at least two polysiloxane surfactants is used. The surfactant is preferably present in the top layer. The amount of surfactant is preferably 0.1.
Within the range of 001 to 0.3 g / m ² , more preferably 0.1 to 0.3 g / m ² .
003 to 0.050 g / m ² .

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
A cyanine dye is a cyanine dye having two indolenine groups. Most preferred is compound I having the structure:

[0032]

Embedded image Particularly useful IR-absorbing pigments are carbon black, metal carbides, borides, nitrides, carbonitrides, bronze-structured oxides and oxides structurally related to the bronze family but without the A component, such as 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.

If the top layer contains an IR-dye,
The top layer also preferably contains a dye or pigment that absorbs in the visible region so that the image formed after R-irradiation and development in an aqueous alkaline developer can be visually inspected.

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 a water-insoluble polymer as a binder, such as cellulose esters, copolymers of vinylidene chloride and acrylonitrile, poly (meth) acrylates, polyvinyl chloride, silicone resins and the like. Preferred as a binder is a nitrocellulose resin.

The total amount of the uppermost layer is preferably 0.010 to
5 g / m ^2, more preferably in the range of 0.020~1g / m ^2.

When image-wise exposed, differences in the capacity of the top layer to be infiltrated 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. To the extent the capacity increases.

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

The invention between the top layer and the lithographic base is preferably an aqueous developer, more preferably preferentially.
ially) comprising a first layer soluble in an aqueous alkaline developer having a pH of 7.5 to 14. The layer is preferably continuous with the top layer, but there can be other layers 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 resins, polymers containing hydroxystyrene units, carboxy-substituted polymers and the like. . A typical example of these polymers is DE-A-400
7 428, DE-A-4 027 301 and DE-
A-4445820. Hydrophobic binders used in connection with the present invention are furthermore insoluble in water and partially soluble / soluble in alkaline solutions.
It is characterized by swelling and / or partial solubility in water when combined with co-solvents.

Furthermore, the aqueous alkali-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 can be anodized aluminum. A particularly preferred lithographic base is an electrochemically roughened and 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, which can further contain 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. Furthermore, it is clear 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.
084070, DE-A-4 423 140, DE-
A-4 417 907, EP-A-659 909,
EP-A-537 633, DE-A-4001 4
66, EP-A-292 801 and EP-A-291
760 and US-P-4458 005.

According to another mode associated with the present invention, a lithographic base having a hydrophilic surface comprises a flexible support, such as a paper or plastic film provided with a cross-linked hydrophilic layer. 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 homopolymers and copolymers of vinyl alcohol, acrylamide, methylolacrylamide, methylolmethacrylamide, acrylic acid, methacrylic acid, hydroxyethyl acrylate, 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 crosslinking agent, 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-based 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 crosslinked hydrophilic layer of the lithographic printing base 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.

It is particularly preferable to use a plastic film, such as a substrate-based polyethylene terephthalate film, a cellulose acetate film, a polystyrene film, a polycarbonate film, etc., as the lithographic printing base flexible support in connection with this embodiment. 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.

The image-wise exposure in connection with the present invention is an image-wise scanning exposure that involves the use of a laser operating in the infrared or near-infrared, ie, 700-1500 nm wavelength region. 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 in the form of silicates, preferably having a pH of from 11.5 to 14. The uppermost imaging portion thus exposed and made more permeable to the aqueous alkaline solution is cleaned, thereby obtaining 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 and the replenisher for the developing solution used in the present invention 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.
Preferably used as such an alkali metal silicate, 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 include ammonium hydroxide, sodium triphosphate, sodium phosphate dibasic, potassium phosphate tribasic, potassium phosphate dibasic, ammonium phosphate tribasic, phosphate dibasic. Inorganic alkaline reagents such as ammonium, sodium bicarbonate, sodium carbonate, potassium carbonate and ammonium carbonate; and mono-, di- or triethanolamine, mono-, di- or trimethylamine, mono-, di- or triethylamine, mono- or Organic alkaline reagents such as di-isopropylamine, n-butylamine, mono-, di- or triisopropanolamine, ethyleneimine, ethylenediimine and tetramethylammonium hydroxide are included.

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 as required. 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, higher alcohols (C ₈ ~C ₂₂₎ salts of sulfuric acid esters,
For example, sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate,
Ammonium salt of lauryl alcohol sulfate, T
eepol B-81 (trademark, Shell Chemi)
cals 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; sulfonates of alkylamides, for example, C ₁₇ H ₃₃ CON (CH ₃ ) CH ₂ C
H ₂ SO ₃ Na and sulfonic acid salts 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 are generally present in an amount of up to 5% by weight, preferably
It can be used in amounts up to 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
Tetramethyldecine diol as disclosed in 920; non-ionic surfactants as disclosed in JN-A-60-213 943; cationic polymers, such as disclosed in JN-A-55-95946. Methyl chloride quaternary product of p-dimethylaminomethyl polystyrene as described
de quaternary products); amphoteric polyelectrolytes such as JN-A-56-142528
Copolymers of vinylbenzyltrimethylammonium chloride and sodium acrylate as disclosed in US Pat.
52 (US-A-4 467 027) and sodium-sulfite and alkali-soluble mercapto or thioether compounds such as thiosalicylic acid, cysteine and thioglycolic acid; inorganic lithium compounds such as JN-A-58- Lithium chloride as disclosed in US Pat. No. 59 444; organolithium compounds such as lithium benzoate as disclosed in JN-A-5034 442; JN-A-59-75 255
JN-A-59-84 241 (US)
-A-4 500 625), organoboron compounds as disclosed in quaternary ammonium salts, for example EP-
A tetraalkylammonium oxide as disclosed in A-101 010; and a bactericide;
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.

[0069]

【Example】

Example 1 Preparation of a lithographic printing base An aluminum foil 0.30 mm thick was degreased by submerging the foil in an aqueous solution containing 5 g / l sodium hydroxide at 50 ° C and rinsing with deionized water. 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
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 1 On a lithographic base, initially 8.6% by weight in a 55/45 ratio of tetrahydrofuran / methoxypropanol
A layer from the solution was coated with a 14 μm wet coating thickness. The resulting layer is 88% ALNOVOL
Contains SPN452 ^™ and 12% 3,4,5-trimethoxybenzoic acid. An IR-sensitive layer was then coated over this layer from a 0.885% by weight solution in methyl ethyl ketone / methoxypropanol in a 50/50 ratio with a wet coating thickness of 20 μm. This layer is 1
Dry at a temperature of 20 ° C. The resulting IR-sensitive layer is 1
15 mg / m ² carbon black, 11.5 mg / m ²
Nitrocellulose, 2.1 mg / m ² SOLSPE
RSE 5000 ^™ (Zeneca Specialia)
ties, available from GB), the 11.3mg / m ² SOLSPERSE 28000 ^TM and 14 mg / m ²
Of FLUORAD FC 431 ^™ . FLU
ORAD FC 431 ^™ is a non-ionic perfluoroaliphatic polymeric ester, available from 3M, USA. Preparation of Heat Mode Imaging Element 2 The element was prepared in the same manner as Element 1 except that FLUORAD FC 431 ^™ was not used in the top layer.

The two elements are GERBER C42T
^TM using the internal drum platesetter (available from Gerber), 12,000 rpm and 2540dpi
And an image was formed. The output level of the laser on the image plane was 4 W.

After IR-image formation, TECHNIGRA
PH NPX-32T^TM(From Technigraph
Available) OZASOL EP 2 in processor
6^TM(9 copies of OZASOL EP 26^TMAnd one part of water
-OZASOL EP 26 ^TMIs Agfa, Germa
1 m / min at 25 ° C.
The material was developed in. For element 1, IR-exposure area
Area very quickly without attack in non-IR-exposed areas
Dissolved to give a positive working version. The version is
normal K + E on elberg GTO 46 printing press
Using these inks and dampening solution from Rotamatic
Print and print excellent, i.e. in the image forming area
No scum formation and excellent in non-IR-exposed areas
A print having good ink-absorption was obtained.
In the case of element 2, the IR-exposed area dissolved very quickly
But at the same time the non-IR-exposed areas were seriously attacked and printed
Excellent image formation on the plate was not obtained.

Example 2 Preparation of Heat Mode Imaging Element 3 On the lithographic base of Example 1, a layer from a 8.6% by weight solution in tetrahydrofuran / methoxypropanol in a 55/45 ratio was first coated with a 14 μm layer. Coated at wet coating thickness. The resulting layer is 88% AL
NOVOL SPN452 ^™ and 12% 3,4,5-
Trimethoxybenzoic acid was included. An IR-sensitive layer was then placed on top of this layer from a 0.3% by weight solution of methyl ethyl ketone / methoxypropanol in a 50/50 ratio.
Coated with a wet coating thickness of 0 μm. This layer was dried at a temperature of 120 ° C. The resulting IR-sensitive layer contains 35 mg / m ² of IR-dye compound 1, 10 mg.
/ M ² of the dye BASONYL-BLAU 636 ^™ (B
Triarylmethane dye commercially available from ASF), 2 mg / m ² TEGOGLIDE 265
^TM (polyether siloxane copolymer) and 5 mg /
m ² TEGOGLIDE 410 ^™ (polyether modified polysiloxane) (both Tego Chemie

A silicon surfactant (commercially available from Service GmbH) was included.

This material was used in CREO TRENDSETT.
ER 3244-T ^TM external drum plate setter (C
186 mJ / cm ^{2 at} 150 rpm and 2400 dpi.
An image was formed using the density.

After IR-image formation, TECHNIGRA
OZASO on PH NPX-32T ^™ Processor
The material was developed at 25 ° C. at 1 m / min using LEP26 ^™ developer (commercially available from Agfa).

The IR-exposed areas dissolved very quickly without attack in the non-IR-exposed areas, giving a positive working printing plate.

The plate is placed on a Heidelberg GTO46 printing press with the usual ink (K + E800) and dampening solution (R
otamatic), excellent print,
That is, a print was obtained that had no scum formation in the IR-exposed areas and excellent ink absorption in the non-image forming areas. Preparation of comparative heat mode imaging element 4:-for this comparative element 4, the surfactant TEGO GLI
DE 265 ^™ and TEGO GLIDE 410 ^™ were omitted from the IR-sensitive top layer of heat mode imaging element 3. This material is called CREO TRENDSETTER
Using a 3244-T ^TM external drum plate setter,
At 2400 dpi, 186 mJ / 150 rpm
Images were formed using an energy density of cm ² .

After IR-image formation, TECHNIGRA
OZASO on PH NPX-32T ^™ Processor
The material was developed at 25 ° C. at 1 m / min using LEP26 ^™ developer (commercially available from Agfa).

The IR-exposed areas melted very quickly with severe attack of the non-IR-exposed areas, giving an unusable printing plate.

On a Heidelberg GTO46 printing press, the usual ink (K + E800) and dampening solution (Rot)
When printed using an organic material, the plate did not have good printing results, ie, there was no good ink-absorption in the non-imaging areas.

Result: The density and Dmax / Dmin of the layer after image formation and processing were determined by MacBeth 918SB.
(Cyan filter).

[0084]

[Table 1] The main features and aspects of the present invention are as follows.

1. On a lithographic printing 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 printing base, wherein the top layer is IR-sensitive A heat mode imaging element for making a lithographic printing plate that is impermeable to an aqueous alkaline developer; wherein at least one of said first layer and said top layer comprises a surfactant. Heat mode imaging element.

2. 2. A heat mode imaging element for making a lithographic printing plate according to claim 1, wherein the surfactant is a surfactant selected from the group consisting of a perfluoroalkyl surfactant and an alkylphenyl surfactant.

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

4. The surfactant is 0.003 to 0.050
A heat mode imaging element for making a lithographic printing plate according to any of the preceding claims, which is present in an amount in the range of g / m < ² >.

5. 5. The heat mode imaging element for making a lithographic printing plate according to any one of the above 1 to 4, wherein the polymer contained in the first layer is a hydrophobic polymer.

6. The above-mentioned 5 wherein the hydrophobic polymer is a novolak resin or a polymer containing hydroxystyrene units.
A heat mode imaging element for making a lithographic printing plate as described in paragraph.

7. Wherein the first layer contains a compound selected from the group consisting of low molecular weight acids and benzophenones.
A heat mode imaging element for making a lithographic printing plate according to any of the preceding claims.

8. A heat mode imaging element for making a lithographic printing plate according to any of the preceding claims, wherein the lithographic printing base is an electrochemically roughened and anodized aluminum support.

9. The electrochemically roughened and anodized aluminum support is polyvinyl phosphonic acid, polyvinyl methyl phosphonic acid, polyvinyl alcohol phosphate, polyvinyl sulfonic acid, polyvinyl benzene sulfonic acid, polyvinyl alcohol sulfate and sulfonated fat. 9. A heat mode imaging element for making a lithographic printing plate according to claim 8 which has been treated with an acetal of polyvinyl alcohol formed by reaction with an aromatic aldehyde.

10. a) exposing the heat mode imaging element of any of the above items 1 to 9 imagewise to IR-radiation; b) using the imagewise exposed heat mode imaging element with an aqueous alkaline developer. And dissolving the exposed region of the uppermost layer and the region below the first layer, and leaving the unexposed region of the first layer undissolved.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Giyoan Belmercille Belgium B 2640 Malt Cell Septes Trat 27 Agfa-Gevuert Na Mrose Fennoutjaps (72) Inventor Guido Hoquier Belgium B 2640 Maltcell septestrat 27 Agfa-Gevert na in Mulose Fennojat-Jap (72) Inventor Eric Bercyuellen Belgium B

Claims (2)

[Claims] 1. A lithographic printing base having a hydrophilic surface, comprising a first layer containing 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 a heat mode imaging element for making a lithographic printing plate that is IR-sensitive and impervious to an aqueous alkaline developer; at least one of the first layer and the top layer contains a surfactant. A heat mode imaging element characterized in that it comprises: 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 region of the uppermost layer and the region below the first layer, and leaving the unexposed region of the first layer undissolved.