JPH10278443A - Original plate for direct draw type lithographic press and its formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plate that can be printed simply, by providing on a substrate at least a hydrophilic swelling layer of a specific dry thickness, a specific water absorption amount and a specific water swelling rate and an ink-accepting heat-sensitive layer containing at least a photothermal conversion substance and a compound easy to decompose with heat, and having a specific dry thickness in this order. SOLUTION: A hydrophilic swelling layer is layered on a substrate, in which a hydrophilic polymer is crosslinked or pseudo crosslinked upon necessities, so that the layer is insoluble to water or has a form retainability. A water absorption amount of the hydrophilic swelling layer is 1-50 g/m<2> . A water swelling rate of a non-image part is 10-200%. Moreover, a dry thickness is preferably 0.5-4 μm. An ink-accepting heat-sensitive layer is required to efficiently absorb laser light and convert the light to heat, thereby being instantaneously decomposed partly or wholly by the heat. A thickness of the ink-accepting heat- sensitive layer is not larger than 3 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor, and more particularly to a novel lithographic printing plate having high ink repellency without desensitizing treatment and capable of using pure water as a fountain solution. More particularly, the present invention relates to a lithographic printing plate precursor capable of directly drawing with a laser beam and a method of making the plate.

[0002]

2. Description of the Related Art In lithographic printing, an image area and a non-image area are basically present on substantially the same plane, and the image area is made ink-receptive and the non-image area is made ink-repellent. Utilizing the difference in adhesiveness, after inking ink only on the image area,
This refers to a method of printing by transferring ink onto a printing medium such as paper. A PS plate is usually used for such lithographic printing.

[0003] The PS plate mentioned here means the following.

[0004] That is, Teruhiko Yonezawa, "PS Version Overview"
As described in pp. 18-81 of the Printing Society of Japan (1993), a lipophilic photosensitive resin layer is applied on an aluminum substrate that has been subjected to hydrophilic treatment, and the image portion is formed by photolithography. The photosensitive layer remains, while the non-image area exposes the surface of the aluminum substrate described above, forms a dampening solution layer on the surface, repels ink, and forms a PS plate with water for forming an image and a dampening solution layer. Instead, a waterless PS plate using a silicone rubber layer as an ink repellent layer, a so-called waterless planographic plate.

[0005] The term "waterless lithographic printing plate" used herein means that the non-image area is made of a substance having ink repellency to oil-based ink used in normal lithographic printing, such as silicone rubber or a fluorine-containing compound. This means a printing plate that can be used to form an image between an ink-impartable image portion and print without using the same.

[0006] The former PS plate with water is a printing plate excellent in practical use. Usually, aluminum is used for the support, and the aluminum surface has water retention and a lipophilic photosensitive resin layer is formed from the surface during printing. It was necessary to have excellent adhesion to the photosensitive layer so as not to peel off. Therefore, the aluminum surface is usually grained, and if necessary, a treatment such as anodizing is performed on the grained surface to improve water retention and reinforce adhesion to the photosensitive resin layer. I have been. Further, in order to obtain the storage stability of the photosensitive resin layer, the aluminum surface is generally subjected to a chemical treatment such as zirconium fluoride or sodium silicate.

As described above, the PS plate with water has a complicated manufacturing process and its simplification has been desired. However, the PS plate has been widely used because of its excellent printing characteristics (printing durability, image reproducibility, etc.). I have.

In order to solve the above-mentioned problem, there is a proposal of a new planographic material having printing characteristics equal to or higher than that of an aluminum substrate, and having a low material cost and different from an aluminum substrate by a simple manufacturing process. For example, Japanese Patent Publication No. Sho 56-2938 proposes a method of forming a photosensitive layer on a support using an ink repellent layer made of a hydrophilic polymer material instead of an aluminum substrate. ing. However, in this method, since a urea resin is simply applied as a hydrophilic layer on a water-resistant layer of an aldehyde condensate of polyvinyl chloride, polyurethane, or polyvinyl alcohol, the layer has insufficient ink repellency. In addition, the adhesiveness to the photosensitive resin layer was poor, and the printing durability was insufficient. Also,
JP-A-57-179852 discloses a method in which a hydrophilic radical polymerizable compound is coated on a support, the surface of the support is hydrophilized by irradiation with actinic rays, and a photosensitive resin layer is coated. Proposed. However, the hydrophilic surface layer formed by this method was also rigid, had insufficient ink repellency, and had poor printing durability.

In the development of the PS plate with water, since the photosensitive layer is dissolved to expose the substrate surface, it is essential that the components of the photosensitive layer be dissolved in the developing solution. Since the composition fluctuates greatly in a short period of time to cause fatigue, a large amount of developing waste liquid is generated. for that reason,
The developer required frequent maintenance and replacement. In addition, a great deal of labor and cost are required for treating the generated developing waste liquid.

Also, as a simple form of the PS plate with water,
An image receiving layer such as toner is formed on a support such as paper
A direct-drawing lithographic printing plate precursor that forms an image using a PC, desensitizes non-image areas with an etchant or the like, and converts the image receiving layer into an ink repellent layer for use is widely used. . Specifically, an image receiving layer comprising a water-soluble binder polymer, an inorganic pigment, a water-proofing agent and the like is generally provided on a water-resistant support, and is disclosed in US Pat. No. 2,532,865, Japanese Patent Publication No. 40-23581, and JP-A-48-9802, JP-A-57-205196, JP-A-60-2
309, JP-A-57-1791, JP-A-5-1791
JP-A-7-15998, JP-A-57-96900, JP-A-57-205196, JP-A-63-1
66590, JP-A-63-166593,
JP-A-63-317388, JP-A-1-1144
No. 88, JP-A-4-366868, and the like. These direct-drawing lithographic printing plate precursors include PVA, starch, hydroxyethylcellulose, casein, gelatin, polyvinylpyrrolidone, vinyl acetate-crotonic acid copolymer, styrene-maleic acid copolymer as an image receiving layer to be converted into an ink repellent layer. Water-dispersible polymers such as water-soluble binder polymers and acrylic resin emulsions that exhibit hydrophilicity before the desensitization treatment such as coalescence, inorganic pigments such as silica and calcium carbonate, and melamine-formaldehyde resin condensates There are proposals made of such a waterproofing agent.

Japanese Unexamined Patent Publication (Kokai) No. 63-256493 proposes a direct drawing type lithographic printing plate precursor using as a main component a hydrophobic polymer which is hydrolyzed by a desensitizing treatment to generate a hydrophilic group. In order to convert the image receiving layer into an ink repellent layer, such a direct-drawing lithographic printing plate requires desensitization treatment, and without such treatment, shows little ink repellency. there were.

That is, in order to obtain a practical level of ink repellency, it is necessary to desensitize the ink and to use a large amount of a hydrophilic binder polymer. However, the water resistance tends to be poor, and the printing durability deteriorates. . Further, when the hydrophilicity is increased, there is a problem that the adhesiveness to an image such as a toner tends to decrease. On the other hand, if the water resistance is increased by increasing the amount of a water-proofing agent or by adding a hydrophobic polymer in order to improve printing durability, the hydrophilicity is reduced, and the ink repellency is greatly reduced. There was a problem.

A so-called one-step exposure-only technology developed by Union Carbide, which does not require development, lacquer embossing and desensitization treatment utilizing a hydrophilic / hydrophobic conversion reaction, is disclosed in No. 131, Japanese Patent Publication No. Sho 4
No. 2-5365, Japanese Patent Publication No. 42-14328,
JP-B-42-20127, US Pat. No. 3,321,377
JP, USP3231381, USP3231
No. 382, for example. The plate is formed by coating an association of polyethylene oxide and a phenolic resin together with a photosensitizer. However, the non-image portion is rigid and inferior in flexibility, and the ink repellency is insufficient. The difference in ink repulsion / ink deposition between the line and
It was not practical.

Further, the PS plate with water needs to constantly control the amount of dampening solution at the time of printing, and considerable skill and experience have been required to control an appropriate amount of dampening solution. IPA added as an essential component to the fountain solution
In recent years, the use of (isopropanol) has been strictly regulated from the standpoint of the occupational health environment and wastewater treatment, and countermeasures are urgently needed.

On the other hand, in the case of a waterless PS plate in which a silicone rubber layer is used as the ink repellent layer instead of the dampening solution, Japanese Patent Publication No.
No. 26923, JP-B-57-3060, JP-B-56-12682, and JP-B-56-23150.
JP, JP-B-56-30856, JP-B-60-30
No. 60051, JP-B-61-54220, JP-B-61-54222, and JP-B-61-54223.
JP, JP-B-61-616, JP-B-63-23
544, JP-B-2-25498, JP-B-3
JP-A-56622, JP-B-4-28098, JP-B5-1934, JP-A-2-63050, JP-A-2-63051 and the like without using dampening water. Can be printed on water, the former with water P
Since it is not necessary to control the dampening solution required for the S plate at all, and the printing operation is extremely simple, it is a highly practical plate material that has been rapidly spreading in recent years. Since a silicone rubber layer having a low strength is used, insufficient durability is pointed out, and there is a strong demand for an ink repellent material having excellent durability.

Meanwhile, recently, as a separate flow from the improvement of the plate material relating to the control of the dampening solution as described above, a so-called direct plate making system for directly producing an offset printing plate from a manuscript without using a plate making film has been developed. It is in the limelight.

This direct plate-making system is simple, does not require skill, is quick to obtain a printing plate in a short time,
Utilizing features such as rationality that can be selected according to quality and cost from various systems, it has begun to enter not only the light printing industry but also the newspaper printing field, as well as the general offset printing and gravure printing fields. .

Particularly recently, new types of various lithographic printing materials have been developed due to rapid advances in output systems such as prepress systems, imagesetters, and laser printers.

These lithographic printing plates can be classified according to the plate making method. A method of irradiating a laser beam, a method of writing with a thermal head, a method of partially applying a voltage with a pin electrode as described above, an ink repelling layer by ink jetting, Alternatively, a method of forming an ink deposition layer may be used.

Above all, the method using laser light is superior to other methods in terms of resolution and plate making speed.
There are many types.

The lithographic printing plate using the laser beam is further classified into two types: a photon mode by photoreaction and a heat mode by performing photothermal conversion to cause a thermal reaction.

Although many photon mode devices that directly draw using a high-sensitivity photopolymer sensitive to a He—Ne or Ar laser have been proposed, the high sensitivity makes the plate material difficult to handle. There is a problem that a large-scale and expensive automatic exposure and development plate making apparatus is required.

Heat destruction which is one of the heat mode types
The thermal reaction method has the advantage that it can be handled in a bright room,
Also, with the rapid progress of the output of a semiconductor laser as a light source, its usefulness has recently been reviewed.

As one of the conventional plate making systems using a PS plate with water, a laser recording film has been proposed in Japanese Patent Publication No. 7-25202. This film has a recording layer and a protective layer containing a non-self-oxidizing binder, heat absorbing fine particles, and a heat ray absorbent on a transparent support, and can output and record image data in a heat mode. . By using this, a so-called direct plate making system using the conventional plate material as it is becomes possible,
It is possible to shorten the time required for producing a film as in the related art. However, there is a problem of adhesion between the film and the plate material at the time of image exposure, a problem of a so-called time required for vacuuming, a problem of burning when insufficient vacuuming is performed, and difficulty in handling when the film is thin. Problem,
There was a problem that plate materials could not be handled in the light room.

Japanese Patent Application Laid-Open No. 8-48018 discloses a method for wet lithographic printing in which an ink receiving layer containing nitrocellulose and absorbing laser light in an ablation manner and a protective layer containing a PVA derivative existing thereunder are laminated on an aluminum substrate. Laser imageable printing members have been proposed. In this material, after the laser exposure, the protective layer is removed by development and the underlying ink repellent substrate is exposed.However, since the ink repellent layer is mainly composed of a conventional aluminum substrate, Had problems due to the dampening solution. In addition, some studies on direct plate making for waterless lithography have been conducted.

For example, US Pat. No. 5,379,698 describes a direct-drawing waterless planographic printing plate using a metal thin film as a heat-sensitive destruction layer. However, since the metal thin film itself reflects laser light to some extent, the sensitivity of the printing plate is reduced. There was a problem of bad. For this reason, in order to increase the absorptivity of the laser beam, an antireflection layer must be provided, and the number of coating steps is further increased, resulting in an increase in cost.

JP-A-6-199064, USP 533
9737, US Pat. No. 5,353,705, EP05803
No. 93 also discloses a direct drawing type waterless planographic printing plate precursor using a laser beam as a light source. The heat-destructible layer of the heat-destructible printing plate precursor uses carbon black as a laser light absorbing compound and nitrocellulose as a thermal decomposition compound. The carbon black is converted into thermal energy by absorbing the laser beam, and the heat destroys the heat-sensitive breakdown layer. Finally, by removing this portion by development, the silicone rubber layer on the surface is simultaneously peeled off to form an ink-coated portion. This printing plate has better laser light absorption than the above-mentioned metal thin film.However, these printing plates have a weak adhesive force between the silicone rubber layer and the heat-sensitive destruction layer on the surface, causing scratches during printing. There was a problem that printing durability was low.

JP-A-6-55723, EP05730
No. 91 also describes a direct drawing type waterless lithographic printing plate of the same type, but also in this case, the adhesion between the silicone rubber layer and the heat-sensitive rupture layer is weakened, and the printing durability is low. Had. Furthermore, the laser used is Nd
-There was another problem that the exposure apparatus became considerably large because of the YAG laser.

Further, since the direct drawing type waterless planographic plate as described above has a structure of a silicone rubber upper layer type having a silicone rubber layer on a heat-sensitive layer, it works as a planographic printing plate at the time of printing. As a result, there is a problem that ink mileage is poor.

To solve this problem, Japanese Patent Publication No. Sho 56-1
No. 4976 proposes a water-sensitive lithographic printing plate having a lower layer of a silicone rubber layer, and Japanese Patent Application No. 7-313172 proposes a laser-sensitive lithographic printing plate having a lower layer of a silicone rubber layer. However, since the silicone rubber layer has a property of easily repelling many liquids, it is extremely difficult to apply a heat-sensitive layer thereon, and even if it can be applied well, the heat-sensitive layer and the silicone rubber layer are not Had insufficient printing strength because of insufficient adhesion.

As described above, many studies have been made on the direct plate making of the conventional PS plate with water and the planographic plate without water. However, as described above, the essential problem is that the PS plate with water has a problem in printing. There is a problem of fountain solution control, while in the case of a lithographic plate without water, there remains a problem of durability of the silicone rubber layer as the ink repellent layer.

Under such circumstances, a printing plate material that can be directly drawn with a laser beam using a layer of a hydrophilic polymer material instead of an aluminum substrate as an ink repellent layer has been proposed.

US Pat. No. 5,353,705 proposes a heat mode recording material in which polyvinyl alcohol is laminated as an ink repellent layer on a laser sensitive layer composed of nitrocellulose and carbon black. However, the ink repellency was extremely insufficient even under the supply of dampening water.

In JP-A-8-282143, the laser-sensitive layer and the hydrophilic swelling layer cause destructive absorption of the laser-sensitive layer and the hydrophilic swelling layer by the action of active light by laser irradiation. Plates with layers have been proposed. In this plate, since the hydrophilic swelling layer having specific properties becomes the ink repellent layer, the problem of the fountain solution at the time of printing which was a problem of the conventional PS plate with water using the aluminum substrate as the ink repellent layer was obtained. No ink repellency was sufficient. However, there is a problem that the ink mileage is very poor because the structure of the printing plate is a planographic printing plate and the ink deposition layer is below the laser sensitive layer.

[0035]

DISCLOSURE OF THE INVENTION The present inventors have developed a conventional fountain solution which is easy to develop, has a wider control range of a fountain solution for lithographic printing of a PS plate with water, and has developed a fountain solution which has been considered impossible. It is possible to eliminate the lack of durability, which is a drawback of a waterless lithographic plate having a silicone rubber layer as an ink repellent layer, without having a complicated plate making process such as a desensitizing treatment. As a result of intensive studies on the development of an ideal lithographic material with good mileage and a simple manufacturing process, the intended purpose can be achieved by forming the hydrophilic swelling layer as an ink repellent layer and forming an image by a specific method. Was found.

[0036]

Means for Solving the Problems That is, the present invention provides: On the substrate, at least (1) a dry film thickness of 5 μm or less, a water absorption of 1 to 50 g / m ² and a water swelling ratio of 10 to 2
A direct drawing type lithographic printing plate precursor comprising, in this order, a hydrophilic swelling layer of 000%, and (2) an ink-receiving thermosensitive layer containing at least a photothermal conversion substance and a thermally decomposable compound and having a dry film thickness of 3 μm or less.

2. The light-to-heat conversion material is carbon black,
2. The direct drawing type lithographic printing plate precursor as described in 1 above, which is an infrared absorbing dye or an infrared absorbing pigment.

3. 3. The direct-drawing lithographic printing plate precursor as described in any one of 1 to 2, wherein the thermally decomposable compound is nitrocellulose.

4. 4. The direct-drawing lithographic printing plate precursor as described in any one of 1 to 3, wherein the ink-receiving thermosensitive layer contains a silane coupling agent.

A direct drawing type lithographic printing plate precursor as described in 5.1 to 4 is irradiated with a laser beam in an image-like manner to decompose the ink-receiving heat-sensitive layer and expose the underlying hydrophilic swelling layer. A plate making method for drawing lithographic printing plates.

6.1 The direct-drawing lithographic printing plate precursor described in 1 to 4 is irradiated with a laser beam in an image-like manner to decompose the ink-receiving thermosensitive layer, and the hydrophilic swelling of the lower layer is caused by friction in the presence of a liquid. A method for making a direct-drawing lithographic printing plate, comprising exposing the layer.

Is provided.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the ink-receiving thermosensitive layer of the direct-drawing planographic printing plate of the present invention will be described. Here, the direct drawing type is used without using a negative or positive film at the time of exposure,
Image formation from a recording head directly on a printing plate.

The ink-receptive heat-sensitive layer used in the present invention needs to efficiently absorb laser light and convert it into heat, and the heat partially or completely decomposes instantaneously.

First, in order to efficiently absorb laser light and convert it into heat, it is important to include a photothermal conversion substance.

The compound is not particularly limited as long as it can absorb light and convert it into heat. For example, carbon black, aniline black, black pigments such as cyanine black, phthalocyanine, naphthalocyanine green pigment, rhodamine dye, aminium salt, naphthoquinone dye, diimonium salt, azuimonium dye, chalcogen dye, carbon graphite, iron powder, Diamine-based metal complexes, dithiol-based metal complexes, phenolthiol-based metal complexes, mercaptophenol-based metal complexes, arylaluminum metal salts, water-containing inorganic compounds, copper sulfate, chromium sulfide, silicate compounds, titanium oxide, vanadium oxide, Metal oxides such as manganese oxide, iron oxide, cobalt oxide, and tungsten oxide;
Examples thereof include hydroxides and sulfates of these metals, and additives such as metal powders of bismuth, tin, tellurium, iron, and aluminum.

Among these, carbon black is preferred from the viewpoints of light-to-heat conversion rate, economy and handling.

Further, carbon black is classified into furnace black, channel black, thermal black, acetylene black, lamp black and the like according to the production method. Furnace black is commercially available in various types in terms of particle size and other aspects. It is preferably used because it is commercially inexpensive.

Although this carbon black is commercially available in various particle sizes, the printing plate of the present invention has a particle size of 15%.
Those having a particle size of from nm to 29 nm are preferred.

If the particle size is smaller than 15 nm, the particles are likely to aggregate to lower the dispersibility. If the particle size is larger than 29 nm, the colorability is reduced and the laser light cannot be efficiently absorbed.

The dyes mentioned above, and dyes that absorb infrared or near-infrared rays other than those described above are also particularly preferably used in the same manner as carbon black, because they are advantageous in terms of dispersibility and coating properties of the coating solution.

Particularly, azine-based dyes are useful, and specific examples thereof include nigrosine, nigrosine-based EX, spirit black SB, spirit black AB, and Balifast black 3810 and 3820.
Further, naphthol blue black and the like can be mentioned.

The combination of the azine dye and the infrared absorber has a particularly preferable composition.

The use amount of these light-to-heat converting substances is preferably from 2 to 70% by weight, more preferably from 5 to 60% by weight, based on the whole ink-receiving thermosensitive layer composition.

When the amount is less than 2% by weight, the sensitivity of the printing plate tends to decrease, and when it is more than 70% by weight, the printing durability of the printing plate tends to decrease.

In order for the ink-receiving heat-sensitive layer to be instantaneously destroyed by irradiation with laser light, it is necessary that the ink-receiving heat-sensitive layer contains a thermally decomposable compound in addition to the light-to-heat conversion substance. preferable.

As the compound satisfying the thermal decomposability, nitro compounds such as ammonium nitrate, potassium nitrate, sodium nitrate and nitrocellulose, organic peroxides, polyvinylpyrrolidone, azo compounds, diazo compounds and hydrazine derivatives are preferably used. Polyvinyl pyrrolidone and nitrocellulose, which are high molecular compounds, are particularly preferred from the viewpoint of solution coatability and the like.

Further, nitrocellulose is JIS K6
It has a hydroxyl group as specified in 703, and this hydroxyl group extremely effectively acts on the adhesion to the hydrophilic swelling layer.

The nitrogen content of nitrocellulose is defined by the degree of nitro group substitution, and the nitrogen content used in the present invention is preferably from 6.8% to 13.5%, more preferably 10.3%. % To 12.8%. When the nitrogen content is less than 6.8%, the sensitivity of the printing plate is reduced. When the nitrogen content is more than 13.5%, it means that the number of hydroxyl groups in one molecule is reduced. Of the adhesive decreases. As a result, there arises a problem that printing durability decreases.

Furthermore, nitrocellulose can be obtained in various molecular weights depending on the average degree of polymerization, and all of them can be used. The nitrocellulose used in the present invention preferably has an average degree of polymerization of 35 to 480. More preferably, it is 45 to 290. If the average degree of polymerization is less than 35, the viscosity of the ink-receiving heat-sensitive layer becomes low and the coating property tends to deteriorate, and if it exceeds 290, the viscosity becomes too high and handling becomes inconvenient.

The amount of the thermally decomposable compound used is preferably from 10 to 80% by weight, more preferably from 20 to 60% by weight, based on the total ink-receiving thermosensitive layer composition. If the amount is less than 10% by weight, the sensitivity of the printing plate is reduced, and
If the amount is more than 0% by weight, sensitivity lowers due to the following decrease in the amount of photothermal conversion substance.

It is preferable to add a silane compound to the ink-receiving heat-sensitive layer for the purpose of strengthening the adhesion to the underlying hydrophilic swelling layer.

As such a silane-based compound, in addition to a known silane coupling agent, any compound having a silyl group can be used. In the present invention, (meth) acrylsilane, vinylsilane and allylsilane are used. And the like. A silane coupling agent having a functional group such as an unsaturated silane coupling agent such as epoxysilane, aminosilane, and mercaptosilane is preferably used.

Specific examples of (meth) acrylsilane include N- (3- (meth) acryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane,
Bis ((meth) acryloxypropyl) -1,1,3
3-tetramethyldisiloxane, 2- (meth) acryloxyethyldimethyl (3- (trimethoxysilyl) propyl) ammonium chloride, (meth) acryloxypropylbis (trimethylsiloxy) methylsilane, 3
-(Meth) acryloxypropyldimethylchlorosilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyldimethylethoxysilane, 3- ( (Meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylpentamethyldisiloxane, 3- (meth) acryloxypropyltris (methoxyethoxy) silane,
3- (meth) acryloxytris (trimethylsiloxy) silane, 2- (trimethylsiloxy) ethyl (meth) acrylate, trimethylsilyl (meth) acrylate, and the like.

Examples of the vinyl silane include bis (dimethylamino) methylvinylsilane, 1-bromovinyltrimethylsilane, chloromethyldimethylvinylsilane, 3-chloropropyldimethylvinylsilane, N, N
-Dimethylaminovinyldiethoxysilane, diphenylvinylethoxysilane, divinyldimethylsilane, 1,
3-divinyl-1,3-diphenyl-1,3-dimethyldisilazane, 1,4-divinyl-1,1,4,4-tetramethyldisilylethylene, phenyldimethylvinylsilane, phenylmethylvinylchlorosilane, phenylvinyldimethoxy Silane, trivinylmethylsilane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, vinylmethyldiethoxysilane, 1-vinylsilatran, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltriphenoxysilane , Vinyl tris (tri-s-butoxysiloxanyl) silane, vinyl tris (t-butylperoxy) silane, vinyl tris (2-methoxyethoxy) silane, vinyl tris (trimethylsiloxy)
Although silane is mentioned, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltrimethoxysilane, divinyldiethoxysilane, and vinyltriacetoxysilane are preferable.

Specific examples of the allyl silane include allyl dimethylchlorosilane, allyl triethoxy silane, allyl trimethoxy silane, diallyl diethoxy silane, diallyl dimethoxy silane, triallyl ethoxy silane,
Phenylallyldimethoxysilane, phenyldiallylethoxysilane, phenyldiallylmethoxycytane, diallyldichlorosilane, diallyldimethylsilane, diphenyldiallylsilane, phenylallyldichlorosilane,
Examples thereof include tetraallyloxysilane and O-trimethylsilylallyl alcohol, and preferred are allyltriethoxysilane, allyltrimethoxysilane, diallyldiethoxysilane, and diallyldimethoxysilane.

As the epoxysilane, 2- (3,4-
Epoxycyclohexyl) ethyltrimethoxysilane,
3-glycidoxypropylmethyldimethoxysilane, 3
-Glycidoxypropyldimethylethoxysilane, 3-
Glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- (N-allyl-N-glycidyl) aminopropyltrimethoxysilane, N-glycidyl-N, N-bis [3- (methyl Dimethoxysilyl) propyl] amine, N-glycidyl-
N, N-bis [3- (trimethoxysilyl) propyl]
Amines and the like.

Examples of the aminosilane include 4-aminobutyldimethylmethoxysilane, 4-aminobutyltriethoxysilane, 4-aminobutyltrimethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, and N- (2-aminoethyl) -3-aminopropylmethylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N-
(2-aminoethyl) -3-aminopropyltris (2
-Ethylhexoxy) silane, 6- (aminohexylaminopropyl) trimethoxysilane, p-aminophenyltrimethoxysilane, 3- (1-aminopropoxy)
3,3-dimethyl-1-propenyltrimethoxysilane, 3-aminopropyltris (methoxyethoxyethoxy) silane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, Examples thereof include 3-aminopropyltris (trimethylsiloxy) silane, 1-trimethoxysilyl-2- (pm-aminomethyl) phenylethane, and trimethoxysilylpropyldiethylenetriamine.

Specific examples of mercaptosilane include 3-
Mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and the like, specific examples of isocyanatesilanes include 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyldimethylchlorosilane, -Isocyanatopropyltrimethoxysilane.

The addition amount of such a silane compound is preferably from 0.01 to 20% by weight, more preferably from 0.05 to 10% by weight, based on the total ink-receiving thermosensitive layer composition.
It is.

Alternatively, a silane coupling agent may be dissolved in an appropriate solvent and applied in a dilute solution to the hydrophilic swelling layer to be used as an adhesive layer.

In this case, the film thickness of the silane coupling agent layer is sufficient if the film thickness is such that a monomolecular film of the silane coupling agent is formed, and specifically, it is preferably 1,000 Å or less. Preferably it is not more than 500 angstroms.

When the thickness is more than 1000 Å, the adhesion to the hydrophilic swelling layer is apt to decrease, and the printing durability and solvent resistance of the printing plate are reduced.

For the purpose of improving the sensitivity of the ink-receiving heat-sensitive layer, it is also effective to add a thermal decomposition aid such as urea and urea derivatives, zinc white, lead carbonate, lead stearate and glycolic acid.

The addition amount of these thermal decomposition aids is preferably from 0.02 to 10% by weight, more preferably from 0.1 to 5% by weight, based on the total ink-receiving thermosensitive layer composition. These ink-receiving thermosensitive layers preferably have a crosslinked structure in order to increase solvent resistance to printing ink. Examples of the polyfunctional crosslinking agent used for introducing a crosslinked structure include an isocyanate compound, an epoxy compound, and a polymerizable monomer.

It is optional to add additives such as a surfactant and a catalyst to the ink-receiving thermosensitive layer as long as the effects of the present invention are not impaired.

The composition for forming the above-described ink-receiving thermosensitive layer is prepared as a composition solution by dissolving the composition in a known suitable solvent or water.

Any solvent can be used as long as it can dissolve or uniformly disperse the composition and can be volatilized in an oven. Examples of the solvent include DMF, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, and the like. Toluene, xylene, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, diethylene glycol diethyl ether, acetone , Methyl alcohol, ethyl alcohol, cyclopentanol, cyclohexanol, diacetone alcohol, benzyl alcohol , Butyl butyrate, ethyl lactate, water and the like can be mentioned.

From the viewpoint of adhesion between the hydrophilic swelling layer and the ink-receiving thermosensitive layer, it is preferable to select a solvent system containing a solvent capable of swelling the hydrophilic swelling layer to some extent.

Examples of such a solvent include water, alcohols such as methanol, ethanol, isopropanol, ethylene glycol and ethylene glycol monomethyl ether, acetone, methyl ethyl ketone, tetrahydrofuran, ethyl acetate, DMF and the like.

By applying the composition solution uniformly on a substrate and heating it at a required temperature for a required time, an ink-receiving thermosensitive layer is formed.

When a crosslinking agent is used in combination, a curing reaction is performed by an appropriate means at the time of coating, at the time of drying after coating, and further after coating and drying.

Drying for forming an ink-receiving thermosensitive layer,
The thermal curing is performed in a range where the thermally decomposable compound is not decomposed, usually 160
It is necessary to carry out the reaction at a temperature of not more than ° C.

It is important that the thickness of the ink-receiving heat-sensitive layer is 3 μm or less. If the film thickness is more than 3 μm, the ink-receiving thermosensitive layer is not completely decomposed at the time of exposure, so that the underlying hydrophilic swelling layer is not exposed. Further, the film thickness is preferably from 0.1 μm to 2 μm, more preferably from 0.3 μm to 1 μm.
If the thickness is less than 0.1 μm, there is a problem that the sensitivity of the ink receptive heat-sensitive layer is apt to be lowered, and that the ink adhesion during printing is poor.

Next, the hydrophilic swelling layer of the direct-drawing planographic printing plate precursor according to the invention will be described.

The hydrophilic swelling layer of the present invention is obtained from a composition containing a hydrophilic polymer as a main component.

First, the hydrophilic polymer will be described. The hydrophilic polymer is a known water-soluble polymer (which means completely soluble in water) or a pseudo-water-soluble polymer (which means amphipathic) which is substantially insoluble in water and shows water swelling. Macro means a substance which dissolves in water but micro means a part which does not dissolve), and water means a water-swellable polymer (means one which swells in water but does not dissolve). That is, it refers to a polymer that adsorbs or absorbs water under normal use conditions, and a polymer that dissolves in or swells in water.

Examples of the hydrophilic polymer that effectively exerts the effects of the present invention include carboxylate copolymers.

The carboxylate copolymers preferably used in the present invention include, from the viewpoint of water absorption and durability,
Α, β-unsaturated compounds having one or two carboxyl groups or carboxyl group-derived groups such as carboxyl groups, carboxylate salts, carboxylic acid amides, carboxylic acid imides, carboxylic anhydrides, etc. A saponification reaction product of a carboxylic acid copolymer contained as a component is exemplified.

Specific examples of the α, β-unsaturated compound include:
Acrylic acid, methacrylic acid, (meth) acrylic amide (in the following description, “(meth) □□□□” refers to □□□□
Or / and meta □□□□. ),
Maleic anhydride, maleic acid, maleic amide, maleic imide, itaconic acid, crotonic acid, fumaric acid, mesaconic acid, and the like, and other monomer components that can be copolymerized within the range showing the hydrophilicity required for the present invention. It is possible to combine with

Examples of other copolymerizable monomer components include α-olefins such as ethylene, propylene, isobutylene, 1-butylene, diisobutylene, methyl vinyl ether, styrene, vinyl acetate, (meth) acrylate, and acrylonitrile. , Vinyl compounds, vinylidene compounds and the like.

When combined with another monomer, the α, β-unsaturated compound containing a carboxyl group or a group which can be converted into the carboxyl group is usually present in an amount of at least 10 mol% of all monomer components.
More preferably, it is at least 40 mol%.

A polymer containing, as a monomer, an α, β-unsaturated compound containing a carboxyl group or a group which can be converted into the carboxyl group is usually prepared by radical polymerization. The degree of polymerization is not particularly limited.

Among the polymers thus prepared, polymers or copolymers with (meth) acrylic acid, α
-Copolymers of olefins, vinyl compounds and maleic anhydride are preferred.

These polymers or copolymers are saponified by using compounds such as hydroxides, oxides or carbonates of alkali metals or alkaline earth metals such as sodium, potassium and magnesium, ammonia and amines. Hydrophilicity is preferably imparted by reacting.

Among such carboxylate copolymers, vinyl ester / (meth) acrylate copolymers are particularly preferred because the hydrophilic swelling layer exhibits an appropriate water swelling property, and the printing durability and ink It is preferable in that both of the resilience are satisfied.

The vinyl ester / (meth) acrylate copolymer preferably used in the present invention can be produced by a known method.

When the amount of the (meth) acrylate component in the copolymer is small, the water absorption is small, and when the amount is too large, the water absorption state is high and the film strength tends to be extremely lowered.

Accordingly, the proportion of the (meth) acrylate component in the starting copolymer is generally preferably in the range of 20 to 80 mol%, and both the water absorption and the mechanical strength when containing water are compatible. 30 to 7
It is preferably 0 mol%.

The vinyl ester used in the present invention includes vinyl acetate, vinyl propionate, vinyl stearate and the like. As the (meth) acrylic acid ester, an alkyl ester of (meth) acrylic acid,
Specific examples include methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester and t-butyl ester.

The copolymer described above preferably undergoes a saponification reaction in the presence of an alkali catalyst. As the solvent used for the saponification reaction, alcohol and an aqueous alcohol solution are preferable. As the catalyst used for the saponification reaction, a known alkali catalyst is used, and an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is particularly preferable.

The salt of the saponification reaction product of the present invention can be arbitrarily changed by a known method. Commonly used salt-forming substances include sodium hydroxide, potassium hydroxide, ammonium hydroxide, monomethylamine,
Dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, monoethanolamine, diethanolamine,
Triethanolamine, monoisopropanolamine,
Diisopropanolamine, triisopropanolamine, N, N-dimethylethanolamine, N, N-dimethylisopropanolamine, cyclohexylamine,
Benzylamine, aniline, pyridine and the like can be mentioned.

Polyvalent metal salts of alkaline earth metal salts such as magnesium and calcium can be added in the form of a mixed salt with the above-mentioned salts.

The hydrophilic swelling layer of the present invention is formed on the substrate by cross-linking or pseudo-cross-linking the above-mentioned hydrophilic polymer, if necessary, to make it insoluble in water or to have shape retention.

Crosslinking or pseudo-crosslinking can be carried out using the hydrophilic polymer alone by using the functional group of the hydrophilic polymer, or can be carried out by adding a crosslinking agent. It is preferable to add a crosslinking agent from the viewpoint of the above.

The cross-linking reaction may be covalent cross-linking or ionic cross-linking.

Examples of the compound used in the crosslinking reaction include known polyfunctional compounds having a crosslinking property, such as polyepoxy compounds, polyisocyanate compounds, poly (meth) acrylic compounds, polymercapto compounds, polyalkoxysilyl compounds, Examples include a polyvalent metal salt compound, a polyamine compound, a polyaldehyde compound, a polyvinyl compound, and hydrazine. The crosslinking reaction is carried out by adding a known catalyst to accelerate the reaction.

Specific examples of known cross-linkable polyfunctional compounds include the following compounds.

(1) Sublimation sulfur, by-product sulfur produced by oxidizing hydrogen sulfide, colloidal sulfur produced by oxidizing hydrogen sulfide in a wet manner, and the like. In addition, thiuram-based compounds such as dithiomorpholine, thioplast tetramethylthiuram disulfide, tetramethylthiuram monosulfide, which decompose when heated to generate sulfur, piperidine pentamethylene thiocarbamate, pipecoline pipecolyl dithiocarbamate, dimethyl dithiocarbamic acid Dithiocarbamate compounds such as sodium, xanthate compounds such as sodium isopropylxanthogenate and zinc butylxanthogenate; thiourea compounds such as thiourea and thiocarbanilide; zinc salts of thiazoles such as diphenylguanidine; sodium salts of mercaptobenzothiazole; dibenzothiazyl disulfide And thiazole compounds such as cyclohexylamine salt of mercaptobenzothiazole.

(2) Aldehydeamine compounds such as butyraldehyde-monobutylamine condensate, butyraldehyde-aniline condensate, heptaaldehyde-aniline reactant, zinc oxide, tellurium, selenium, ammonia zirconium carbonate, benzoyl peroxide, Organic peroxides such as dicumyl peroxide.

Examples of the crosslinking accelerator include zinc carbonate, stearic acid, oleic acid, lauric acid, zinc stearate, dibutylammonium oleate, diethanolamine, triethanolamine and diethylene glycol.

(3) Polyepoxy compounds, urea resins, polyamines, melamine resins, benzoguanamine resins, acid anhydrides and the like.

Specific examples of the polyepoxy compound include glycerin dipolyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, and sorbitol polyglycidyl ether.

Specific examples of the polyamine include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine,
And polyamidoamine.

(4) Polyisocyanate compounds and the like.

Examples of the polyisocyanate compound include:
Examples include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, cyclohexyl diisocyanate, and tripropylene glycol / tolylene diisocyanate addition reaction products.

These crosslinking agents can be used alone or in combination of two or more.

As a crosslinking agent to be used, a water-soluble polyfunctional compound is preferably used. That is, it is preferable to use a water-soluble polyepoxy compound, polyamine compound, melamine compound, or the like.

The hydrophilic swelling layer used in the lithographic printing plate precursor according to the invention preferably has a phase-separated structure composed of at least two phases of a hydrophilic part phase and a hydrophobic part phase.

Such a phase-separated structure can be obtained from (1) a hydrophilic polymer alone and (2) a hydrophilic polymer to which a crosslinking agent is added, as described above. The added mixture, i.e. (3) a system of hydrophilic and hydrophobic polymers, (4) a hydrophilic polymer,
It can also be obtained from a system of a hydrophobic polymer and a crosslinking agent.

The hydrophobic polymer which can be used for the hydrophilic swelling layer of the present invention will be described.

The hydrophobic polymer used in the present invention is preferably one mainly composed of an aqueous emulsion.

The aqueous emulsion referred to in the present invention means an aqueous hydrophobic polymer suspension in which particles comprising fine polymer particles and, if necessary, a protective layer surrounding the particles are dispersed in water.

That is, it means a self-emulsifying or forced emulsifying aqueous solution basically composed of emulsion particles composed of polymer particles as a dispersoid, a protective layer formed as required, and a dilute aqueous solution as a dispersion medium. Specific examples of the aqueous emulsion used in the present invention include a vinyl polymer latex, a conjugated diene polymer latex, and an aqueous or water-dispersed polyurethane resin.

Examples of the vinyl polymer type latex include acrylic type, vinyl acetate type and vinylidene chloride type.

As the conjugated diene polymer latex,
Styrene / butadiene type (hereinafter abbreviated as SB type), acrylonitrile / butadiene type (hereinafter abbreviated as NB type),
Methyl methacrylate / butadiene (hereinafter abbreviated as MB), chloroprene, and the like.

As the aqueous or water-dispersible polyurethane resin, a hydrophobic polyurethane resin comprising polyester polyol, polyether polyol, poly (ester / ether) polyol and polyisocyanate is forcibly emulsified using a surfactant. Emulsifying type, self-emulsifying type in which a hydrophilic group or a hydrophilic segment is imparted to the resin itself and emulsified in a self-dispersing manner, and non-reactive ones and a reactive agent such as an isocyanate group are blocked with a blocking agent. Reactive substances.

Among these aqueous emulsions, the hydrophobic polymer particularly preferably used in the present invention is SB.
, NB-based, MB-based, and chloroprene-based conjugated diene polymer-based latex.

As the conjugated diene polymer mentioned here,
1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene (chloroprene)
Means a compound having an unsubstituted or substituted 1,3-butadiene skeleton having a carbon-carbon double bond at the 1,3-position, such as a homo- or block copolymer rubber (polymer) having these as essential components. .

Examples of the block copolymer rubber include 1,3-diene such as 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene), styrene and α-methyl which give a glassy polymer at ordinary temperature. A block copolymer with a monovinyl-substituted aromatic compound such as styrene and vinyltoluene is exemplified.

Specific examples of the homo- and copolymer rubbers used in the present invention include polybutadiene, polyisoprene (including natural rubber), polychloroprene, styrene-butadiene copolymer, carboxy-modified styrene-butadiene copolymer, acrylic Acid ester-butadiene copolymer (for example, butadiene-2-ethylhexyl acrylate copolymer), methacrylic acid ester-butadiene copolymer, isobutylene-isoprene copolymer, acrylonitrile-butadiene copolymer, carboxy-modified acrylonitrile-butadiene copolymer Coalesce, acrylonitrile-isoprene copolymer, vinylpyridine-butadiene copolymer, vinylpyridine-styrene-butadiene copolymer,
Styrene-isoprene copolymer and the like can be mentioned.

As described above, the hydrophilic swelling layer of the present invention is obtained by mixing a hydrophilic polymer and the above-mentioned hydrophobic polymer and, if necessary, crosslinking or pseudo-crosslinking to insolubilize in water or maintain shape retention. By being held, they are laminated on the substrate.

Crosslinking may be carried out by forming a crosslinked structure using a polyfunctional compound as described above, or by preparing an aqueous emulsion which is preferably used as the hydrophobic polymer of the present invention. As a carboxyl group,
A method in which a reactive functional group such as a hydroxyl group, a methylolamide group, an epoxy group, a carbonyl group, and an amino group is present to cause self-crosslinking is used.

A known hydrophilic polymer can be added to the hydrophilic swelling layer of the present invention as long as the effects of the present invention are not impaired. The following examples can be given as known hydrophilic polymers.

(A) Natural Polymers Compounds obtained by graft-polymerizing acrylonitrile, acrylic acid, etc. to starch or cellulose, cellulose derivatives such as carboxylated methylcellulose, hydroxyethylcellulose, hyaluronic acid, agarose, collagen, milk casein, etc. Various caseins and their derivatives, glue, gelatin, gluten, soy protein, alginate, arabic gum, Irish moss, soy lecithin, pectic acid, agar, dextrin, mannan, etc.

(B) Synthetic polymers Polyvinyl alcohol, polyethylene oxide, aqueous urethane resin, water-soluble polyester, hydroxyethyl (meth) acrylate polymer, maleic anhydride copolymer, N-vinylcarboxylic acid amide copolymer Coalescent, vinylpyrrolidone-based copolymer, polyethylene glycol di (meth) acrylate-based crosslinked polymer, polypropylene glycol di (meth) acrylate-based crosslinked polymer and the like.

The above-mentioned hydrophilic polymer may contain one or two monomers or copolymer components having different substituents for the purpose of imparting flexibility or controlling hydrophilicity, as long as the effects of the present invention are not impaired. It is possible to mix and use more than one kind as appropriate.

Water is mainly used as the dispersion medium, but a known organic solvent can be added as necessary. As a method of adding the organic solvent, a method of adding as a polymerization solvent and a method of adding as a mixed solvent to an emulsion solution after emulsion polymerization are possible.

It is important that the hydrophilic swelling layer used in the present invention has a specific range of water absorption calculated according to the following method.

Water absorption (g / m ² ) = W _WET −W _DRY W _DRY : Weight in dry state (g / m ² ) W _WET : Weight after immersion in water at 25 ° C. × 10 minutes (g)
/ M ² ) [Method of measuring water absorption] A lithographic printing plate precursor to be measured is cut into a predetermined area and immersed in purified water at 25 ° C. 1
After immersion for 0 minutes, the excess liquid adhering to the front and back surfaces of the hydrophilic swelling layer of the master was quickly wiped off with “Hize gauze” (cotton cloth: manufactured by Asahi Kasei Kogyo Co., Ltd.), and the swelling weight W _{WET of the master was obtained.} Weigh After that, the master
Dry in an oven for about 30 minutes and weigh the dry weight W _DRY .

It is important that the water absorption of the hydrophilic swelling layer of the present invention is from 1 to 50 g / m ² from the viewpoint of ink repulsion and form retention, and is from 1 to 10 g / m ² , and more preferably from 2 to 7 g / m ² .
g / m ² .

It is important that the hydrophilic swelling layer used in the present invention has a water swelling ratio calculated according to the following method within a specific range.

Water swelling rate (%) = (Θ _WET −Θ _DRY ) / Θ _DRY × 100 Θ _DRY : Thickness (μm) of hydrophilic swelling layer composed of non-image area in dry state Θ _WET : Non-swelling in non-swelled state Thickness (μm) of hydrophilic swelling layer composed of image area [Method of measuring water swelling ratio (A)] After the lithographic printing plate precursor to be measured is sufficiently washed and dried, a predetermined portion becomes a cross section. And cut into pieces. After vacuum-drying this section at room temperature for one day and night, the thickness of the hydrophilic swelling layer at the site is observed with an optical microscope, and this is defined as _ΘDRY (μm). The observation with an optical microscope was performed quickly in an environment of 23 ° C. and 20% RH.

Further, an excess water droplet was placed on the lithographic printing plate section, the cross section was observed with an optical microscope in a state where the hydrophilic swelling layer was sufficiently swollen with water, and the thickness of the hydrophilic swelling layer at the site was read.と_する_WET (μm).

[Method of Measuring Water Swelling Ratio (B)] The lithographic printing plate precursor to be measured is sufficiently washed with water and dried.
After exposing the hydrophilic swelling layer with OsO ₄ by exposing it in an atmosphere of an O ₄ aqueous solution for a day and a night, it is cut with a microtome so that a predetermined portion has a cross section to produce an ultrathin section. The thickness of the hydrophilic swelling layer of the section was observed at a magnification of about 10,000 to 50,000 times with a transmission electron microscope (TEM).
_DRY (μm).

On the other hand, after the lithographic printing plate precursor to be measured is sufficiently washed and dried, it is immersed in an OsO ₄ aqueous solution for 2 to 3 days to solidify / fix the hydrophilic swelling layer in a water swelling state. An ultra-thin section is prepared by cutting with a microtome so that a predetermined portion has a cross section, and this section is taken with a transmission electron microscope (TE
In M), the thickness of the hydrophilic swelling layer at the site is read at a magnification of about 10,000 to 50,000 times, and this is defined as Θ _WET (μm).

It is important that the water swelling ratio of the non-image area composed of the hydrophilic swelling layer of the present invention is from 10 to 2000% from the viewpoint of ink resilience and form retention, and from 50 to 1700.
%, More preferably in the range of 50 to 700%. When the water swelling ratio is less than 10%, the resilience of the ink is reduced, and defects such as pinholes are likely to occur during coating. On the other hand, when the water swelling ratio is larger than 2000%,
Shape retention is greatly reduced, and the sheet is easily damaged during printing.

The dry film thickness of such a hydrophilic swelling layer is 5 μm.
It is important that it is less than m. If the dry film thickness is more than 5 μm, the water retention amount on the plate surface becomes too large due to the relationship between the water absorption amount and the water swelling ratio as described above, resulting in problems such as water loss during printing. Further, the dry film thickness is preferably 0.5 μm to 4 μm. If the dry film thickness is too small, the ink repellency becomes insufficient and the effect of blocking morphological defects on the substrate surface is poor.

On the surface of the direct drawing type lithographic printing plate precursor of the present invention, an appropriate protective layer is formed on the uppermost layer by coating for the purpose of protecting the plate surface, or a plain or irregularly treated thin protective film is laminated. Is also good. Specific examples of the protective film include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, cellophane, and the like.

The substrate of the lithographic printing plate precursor used in the present invention is not limited at all, except that it is required to have flexibility that can be attached to an ordinary lithographic printing press and to withstand the load applied during printing.

Typical examples are a metal plate of aluminum, copper, iron or the like, a plastic film such as a polyester film or a polypropylene film or coated paper,
Rubber sheets and the like can be mentioned. Further, the substrate may be a composite of the above materials.

The surface of the substrate may be subjected to various surface treatments or the application of a primer layer for the purpose of improving plate inspection and adhesion, but the primer layer must satisfy the following conditions. . That is, the substrate and the hydrophilic swelling layer are well adhered to each other, are stable over time, and have good solvent resistance to the solvent of the developer. Those satisfying such conditions include those containing an epoxy resin as disclosed in JP-B-61-54219, polyurethane resins, phenol resins, acrylic resins, alkyd resins, polyester resins, polyamide resins, melamine resins. Uses urea resin, benzoguanamine resin, vinyl chloride resin, polyvinyl butyral resin, ethylene-vinyl acetate copolymer, polycarbonate resin, polyacrylonitrile-butadiene copolymer, polyether resin, polyether sulfone resin, milk casein, gelatin, etc. You can do it. These resins can be used alone or in combination of two or more. Among these,
It is preferable to use a phenol resin, a polyurethane resin, a polyester resin, an acrylic resin, an epoxy resin, a urea resin, or the like alone or as a mixture of two or more.

As the anchoring agent constituting the primer layer, a known adhesive such as a silane coupling agent can be used, and an organic titanate is also effective.

It is optional to add a surfactant for the purpose of further improving the coatability.

It is preferable that the primer layer contains additives such as dyes and pigments to improve the plate inspection.
In this case, any dyes and pigments can be used as long as they have a hue different from that of the heat-sensitive destruction layer, but green, blue and yellow dyes and pigments or white pigments are preferable.

The thickness of the primer layer is 0.5
５０50 g / m ² , preferably 1-10 g
/ M ² . When the thickness is less than 0.5 g / m ² , the effect of blocking morphological defects and chemical adverse effects on the substrate surface is reduced,
If the thickness is more than 50 g / m ^2, it is disadvantageous from an economic viewpoint, so the above range is preferable.

Next, a method of making a direct-drawing lithographic printing plate according to the present invention will be described. The direct drawing type lithographic printing plate of the present invention is imagewise exposed with a laser beam after the protective film is peeled off or from above the protective film.

A laser beam is usually used for exposure,
At this time, the light source has a transmission wavelength of 300 nm to 1500.
Ar ion laser, Kr ion laser, He-Ne laser, He-Cd laser, ruby laser, glass laser, semiconductor laser, YAG in the nm range
Laser, titanium sapphire laser, dye laser,
Various lasers such as a nitrogen laser and a metal vapor laser can be used.

Among them, semiconductor lasers are preferably used because they are downsized due to recent technological advances and economically more advantageous than other laser light sources.

The direct-drawing lithographic printing plate exposed by the above method is subjected to printing by peeling off the protective film if it is present, but may be subjected to a development treatment in some cases.

The development is carried out by rubbing or wiping the plate surface with or without a developing solution using a nonwoven fabric, absorbent cotton, cloth, sponge, brush or the like.

As the developer, water, water containing an organic solvent or a surfactant, or various organic solvents is used.

Alternatively, by using an automatic developing machine as described in JP-A-63-163357, the plate surface is pretreated with a developing solution and then rubbed with a brush or by spraying hot water or steam onto the plate surface. Can be developed.

In the present invention, the ink-accepting heat-sensitive layer at the portion exposed to the laser beam is destroyed, and the underlying hydrophilic swelling layer is exposed to form a non-image area. on the other hand,
The unexposed part has the ink-receiving thermosensitive layer remaining,
The ink is deposited and becomes the image area.

Next, a printing method using a printing plate prepared from the planographic printing plate precursor of the invention will be described.

For the lithographic printing of the present invention, a known lithographic printing machine is used. That is, sheet-fed and rotary printing machines of the offset and direct printing type are used.

After the lithographic printing plate precursor of the present invention has been subjected to image formation, the lithographic printing plate precursor is mounted on a plate cylinder of these lithographic printing presses, and ink is supplied to the plate surface from an ink applying roller which comes into contact with the plate surface.

The non-image area having a hydrophilic swelling layer on the plate swells with dampening water supplied from a dampening water supply device, and repels ink. On the other hand, the image portion receives ink and supplies the ink to the surface of the offset blanket cylinder or the surface of the printing medium to form a printed image.

As a dampening solution used for printing on a printing plate obtained from the lithographic printing plate precursor of the present invention, it is of course possible to use an etchant used for a PS plate with water. Pure water containing no substances can be used.

When printing using the lithographic printing plate of the present invention, it is preferable to use pure water having no additive.

[0171]

The present invention will be described in more detail with reference to the following examples.

Synthesis Example 1 <Synthesis of hydrophilic polymer-1> 60 g of vinyl acetate and 40 g of acrylic acid to which 0.5 g of benzoyl peroxide was added as a polymerization initiator, and partially saponified polyvinyl alcohol was used as a dispersion stabilizer. It was dispersed in 300 ml of water containing 3 g and 10 g of NaCl.

The dispersion was stirred at 65 ° C. for 6 hours to carry out suspension polymerization. The methyl acrylate component of the obtained copolymer was identified from the NMR spectrum to be 48 mol%. The intrinsic viscosity in a benzene solution at 30 ° C. was 2.10.

Next, 8.6 g of the copolymer was added to a saponification reaction solution consisting of 200 g of methanol, 10 g of water and 5 g of NaOH in 40 ml, and the mixture was stirred and suspended.
After performing the saponification reaction for 1 hour, the temperature was raised to 65 ° C., and the saponification reaction was further performed for 5 hours.

The obtained saponification reaction product was sufficiently washed with methanol and freeze-dried. The degree of saponification was 98.3 mol%, and as a result of measurement of an infrared absorption spectrum, 3400 cm
Broad absorption attributed to hydroxyl group near ^-1 and 157
At 0 cm ^-1 , strong absorption attributed to the -COO ^- group was confirmed.

Example 1 Aluminum plate having a thickness of 0.15 mm (manufactured by Sumitomo Light Metal Co., Ltd.)
After applying the following composition, a heat treatment was performed at 180 ° C. for 30 minutes to form a hydrophilic swelling layer having a thickness of 3 g / m ² .

<Composition of hydrophilic swelling layer (parts by weight)> (1) 10 parts by weight of hydrophilic polymer-1 (2) 1 part by weight of glyoxal (3) 90 parts by weight of purified water Hydrophilicity coated as described above A composition having the following composition was uniformly applied on the swelling layer so that the coating amount was 1.0 g / m ^2, and heat-treated at 100 ° C. for 3 minutes to obtain a direct drawing type lithographic printing plate precursor.

<Composition of Ink-Receiving Thermosensitive Layer (Parts by Weight)> (1) Nitrocellulose (viscosity 1/2 second, nitrogen content 11.0% "Bergerac NC") (SPN Japan, Inc.) )) 25 parts by weight (2) Carbon black (# 30 manufactured by Mitsubishi Chemical Corporation) 15 parts by weight (3) 3-methacryloxypropyltriethoxysilane 2 parts by weight (4) Polyvinyl butyral (# 2000-L electrochemical) 20 parts by weight (5) Irgacure 651 (manufactured by Ciba Geigy) 7 parts by weight (6) Methyl ethyl ketone 700 parts by weight The protective film of the printing plate was peeled off, and a thermal image setter TE-R1070 ( Dainippon Screen Co., Ltd.
), And image exposure was performed.

The resulting printing plate was rubbed with a developing pad (3M) impregnated with tap water to obtain a printing plate. afterwards,
The printing plate was mounted on a sheet-fed offset printing machine “Sprint 25: manufactured by Komori Corporation”, and printed using high-quality paper (62.5 kg / chrysanthemum) while supplying commercially available purified water as a dampening solution. A printed matter faithfully reproducing the positive image was obtained.

The water absorption of the non-image area was 21.5 g / m ^{2 as} measured according to the definition. The water swelling ratio of the non-image area was 470% as measured according to the definition.

At the time when about 3,000 sheets were printed, no ink stain was generated on each printing plate, and a clear printed matter having a sufficient contrast was obtained.

Example 2 The following primer composition was applied to a 0.15 mm-thick aluminum plate (manufactured by Sumitomo Metal Co., Ltd.) using a bar coater, and heated at 220 ° C. for 2 minutes to give 5 g. /
An m ² primer layer was provided.

(1) 90 parts by weight of a polyurethane resin (SAMPLEN LQ-T1331, manufactured by Sanyo Chemical Industries, Ltd.) (2) 15 parts by weight of a block isocyanate (Takenate B830, manufactured by Takeda Pharmaceutical Co., Ltd.) 3) Epoxy phenol urea resin (SJ9372, manufactured by Kansai Paint Co., Ltd.) 8 parts by weight (4) Tetraglycerol dimethacrylate 0.2 parts by weight (5) Dimethylformamide 725 parts by weight After applying the composition described below, a heat treatment was performed at 150 ° C. for 80 minutes to form a hydrophilic swelling layer having a thickness of 3 g / m ² .

<Composition of hydrophilic swelling layer (parts by weight)> (1) 75 parts by weight of hydrophilic polymer-1 (2) 5 parts by weight of tetraethylene glycol diglycidyl ether (3) 18 parts by weight of aqueous latex "JSR0548" [carboxy] Modified styrene-butadiene copolymer latex: manufactured by Nippon Synthetic Rubber Co., Ltd.] (4) 2-aminopropyltrimethoxysilane 2 parts by weight (5) Purified water 900 parts by weight On the hydrophilic swelling layer coated as described above, The ink receptive thermosensitive layer composition of Example 1 was applied to a dry film thickness of 1 g / m ² using a wheeler (rotary coating device),
Drying in hot air of 1 ° C. for 1 minute yielded a direct drawing type lithographic printing plate precursor.

(1) 25 parts by weight of nitrocellulose (“Bergerac NC” manufactured by SNP Japan Ltd.) (viscosity 1/4 second, nitrogen content 11.0%) (2) copper phthalocyanine ( (3) Carbon black "RAVEN1255" (manufactured by Columbian Carbon Japan Co., Ltd.) 15 parts by weight (4) 3-aminopropyltriethoxysilane 1 part by weight (5) Epoxy resin Denacol “EX512” (manufactured by Nagase Kasei Kogyo) 50 parts by weight (6) Urea resin “Beckamine” P-138 10 parts by weight (7) Methyl ethyl ketone 700 parts by weight The obtained lithographic printing plate precursor was treated in the same manner as in Example 1. After exposure and development to obtain a printing plate, evaluation was made in the same manner. Water absorption of non-image area,
The water swell rates were 15.7 g / m ² and 510%, respectively.
Met.

Example 3 The following heat-sensitive layer composition was applied on the hydrophilic swelling layer of Example 1 using a bar coater, and dried in hot air at 100 ° C. for 2 minutes to form a 1.5 μm dry ink film. A receptive heat-sensitive layer was provided to obtain a direct-drawing lithographic printing plate precursor.

(1) 40 parts by weight of polyvinylpyrrolidone (“K-120” manufactured by ISP Japan) (2) 5 parts by weight of “IR-820B” (infrared absorbent manufactured by Nippon Kayaku Co., Ltd.) (3) “Nigrosine” (4) 3-glycidoxypropyltrimethoxysilane 0.5 parts by weight (5) Methyl ethyl ketone 50 parts by weight (6) Methanol 20 parts by weight (7) Methyl cellosolve 40 parts by weight The obtained lithographic printing plate precursor was exposed in the same manner as in Example 1 to obtain a printing plate, and then printed in the same manner. As a result, a printed matter in which a positive image was faithfully reproduced was obtained.

The water absorption and the water swelling ratio of the non-image area were 2
1.0 g / m ² and 460%.

Comparative Example 1 A plate was produced in the same manner as in Example 1, except that the dry film thickness of the hydrophilic swelling layer was changed to 7 μm. When printing was performed in the same manner as in Example 1, the ink density in the highlight portion of the image area was low, that is, the ink deposition failure in a so-called "water-depleted" state occurred.

Comparative Example 2 In Example 1, the dried film thickness of the ink receptive heat-sensitive layer was 5
A plate was prepared in the same manner as in Example 1 except that the thickness was changed to μm.
Image exposure was carried out in the same manner as in Example 1, and development was carried out by rubbing with a developing pad (manufactured by 3M) similarly soaked in tap water. Only the lower hydrophilic swelling layer could not be exposed.

Comparative Example 3 The photosensitive layer of a normal PS plate (FPQ; manufactured by Fuji Photo Film Co., Ltd.) was extracted with acetone and then with DMF, and then removed.
A protective layer having the following composition was applied to a roughened aluminum substrate that had been heat-treated at 0 ° C. for 5 minutes so as to have a dry film thickness of 3 g / m ^2, and the ink-receiving thermosensitive layer of Example 1 of the present invention was further applied. And a lithographic printing plate precursor was obtained.

<Protective Layer> (1) Polyvinyl alcohol 5 parts by weight (“Gohsenol KL-05” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) (2) Purified water 95 parts by weight This plate was prepared in the same manner as in Example 1 of the present invention. Then, when exposed,
The ink-receiving thermosensitive layer in the exposed area was almost burned off, and a positive image was obtained. The film was further developed with water to remove the protective layer on the exposed portion, thereby exposing the lower aluminum substrate.

This plate and the lithographic printing plate used in Example 1 of the present invention were mounted on the same plate cylinder, and printing was performed while supplying commercially available purified water as fountain solution.

When the supply amount of the dampening solution was increased from the standard condition, the ink density of the image area was extremely reduced in the portion using the plate of the comparative example, and the ink deposition failure due to the so-called "water loss" was observed. There has occurred. On the other hand, in the portion where the lithographic printing plate used in Example 1 was used, the degree of poor inking was slight.

Further, when the supply amount of the dampening solution was reduced from the standard condition, ink staining occurred on the entire surface of the portion using the plate of the comparative example. On the other hand, in the portion using the lithographic printing plate used in Example 1, good printed matter was obtained.

Comparative Example 4 In Example 1, a layer having the following composition was used in place of the hydrophilic swelling layer, and heat-treated at 150 ° C. for 60 minutes.
^A plate was produced in exactly the same manner as in Example 1 except that the layer had a thickness of ² .

(1) 78 parts by weight of chloroprene latex (2) 5 parts by weight of ethylene glycol diglycidyl ether (3) 2 parts by weight of 2-aminopropyltrimethoxysilane (4) 15 parts by weight of aqueous latex “JSR0548” (carboxy-modified styrene) -Butadiene copolymer latex: manufactured by Dainippon Ink and Chemicals, Inc. (5) 900 parts by weight of purified water Exposure and development were carried out in the same manner as in Example 1 to obtain a printing plate. As a result of measuring the water swelling ratio according to the definition, it was 8.7%, which was out of the range of the present invention. When printing was carried out in the same manner as in Example 1, the ink which did not originally repel the ink which should have been a non-image area was obtained, and a printed matter with ink smear on the entire surface was obtained.

Comparative Example 5 Example 1 was repeated except that a layer having the following composition was used in place of the hydrophilic swelling layer and heat-treated at 150 ° C. for 60 minutes to form a layer having a dry film thickness of 2 g / m ^2. A plate was produced in exactly the same manner as in Example 1.

(1) Gelatin 100 parts by weight (2) Ethylene glycol diglycidyl ether 20 parts by weight (3) 2-aminopropyltrimethoxysilane 2 parts by weight (4) Purified water 900 parts by weight Exposure was performed in the same manner as in Example 1. Although a printing plate was obtained by performing development, the water absorption of the non-image area was measured according to the definition. As a result, it was 0.8 g / m ² , which was out of the range of the present invention. When printing was carried out in the same manner as in Example 1, the ink which did not originally repel the ink which should have been a non-image area was obtained, and a printed matter with ink smear on the entire surface was obtained.

Comparative Example 6 In Example 1, a layer having the following composition was used in place of the hydrophilic swelling layer, treated at 100 ° C. for 3 minutes, and dried to a thickness of 3 μm.
A plate was produced in exactly the same manner as in Example 1, except that the layer had a thickness of m.

(1) Acrylamidomethylpropanesulfonic acid / 100 parts by weight Methyl methacrylate copolymer (composition ratio: 50:50 (weight ratio)) (2) Ethylene glycol diglycidyl ether 20 parts by weight (3) 2-aminopropyl tri 2 parts by weight of methoxysilane (4) 900 parts by weight of purified water Exposure and development were carried out in the same manner as in Example 1 to obtain a printing plate, but the water absorption of the non-image area was measured according to the definition. 63 g / m ² was out of the range of the present invention. When printing was performed in the same manner as in Example 1, 5
There was a problem that the ink was not sufficiently deposited on the image area even when 000 sheets were printed.

[0202]

The photosensitive lithographic printing plate precursor according to the present invention has a hydrophilic swelling layer and an ink-receiving heat-sensitive layer having a light-to-heat conversion substance on a substrate in this order, so that it is simpler than a conventional PS plate. We can supply printable direct-drawing plates.

The lithographic printing plate obtained from the original plate exhibits high ink repellency without performing a special surface treatment on a substrate necessary for exhibiting ink repellency in a conventional PS plate. Further, the ink can be efficiently repelled with a small amount of dampening water supplied, and the control range of the dampening water can be expanded. Further, printing can be performed without using a solvent such as isopropanol which is usually added to the dampening solution.

Claims (6)

[Claims] 1. The method according to claim 1, wherein at least (1) a dry film thickness of 5
μm or less, a hydrophilic swelling layer having a water absorption of 1 to 50 g / m ² and a water swelling ratio of 10 to 2,000%, (2) containing at least a photothermal conversion substance and a thermally decomposable compound, and a dry film thickness of 3 μm.
A direct-drawing lithographic printing plate precursor having an ink-receiving thermosensitive layer of m or less in this order. 2. The lithographic printing plate precursor according to claim 1, wherein the light-to-heat converting substance is carbon black, an infrared absorbing dye, or an infrared absorbing pigment. 3. The lithographic printing plate precursor according to claim 1, wherein the thermally decomposable compound is nitrocellulose. 4. The direct-lithographic printing plate precursor according to claim 1, wherein the ink-receiving heat-sensitive layer contains a silane coupling agent. 5. A method for irradiating a laser beam imagewise to the direct-drawing lithographic printing plate precursor according to claim 1 to decompose the ink-receiving heat-sensitive layer to expose the lower hydrophilic swelling layer. The method of making a direct-drawing lithographic printing plate. 6. A direct drawing type lithographic printing plate precursor according to claim 1, wherein the ink receiving thermosensitive layer is decomposed by irradiating a laser beam in an image form, and the lower layer is hydrophilic by friction in the presence of a liquid. A method for making a direct-drawing lithographic printing plate, characterized by exposing a hydrophilic swelling layer.