JP2005074920A - Printing plate material and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing plate material, on the base material of which a hydrophilic surface can be formed by a low cost coating and the performances such as the latitude of water quantity, a non-image part hard to be stained and a blanket hard to be stained as a printing plate of which are equal to or more than those of the aluminum grained printing plate and which has enough plate wear resistance, and a printing method, in which the printing plate material is employed and a board-the-press development is included. <P>SOLUTION: The printing plate material has, on its base material, constituent layers, one of which includes a material A selected from a group consisting of polyglycosamine or a derivative of polyglycosamine. The printing method employs the printing plate material, and in the method the plate is developed on a printing press. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printing plate material and a printing method, and more particularly to a printing plate material capable of forming an image by a computer-to-plate (CTP) method and a printing method using the printing plate material.

  Conventionally, the aluminum base hydrophilic surface of the PS plate for lithographic printing plates, so-called aluminum grain, has been roughened to impart water retention and printing durability, and further to impart hydrophilicity and wear resistance. An oxide film layer forming process by anodization and a hydrophilization process of the anodized film layer have been performed.

  The rough surface processing methods are generally chemical (alkali / acid dissolution, etc.), mechanical (brush polishing using an abrasive, sand blasting, liquid honing, rolling with a roughness transfer roll, etc.), electrochemical Surface roughness (AC or DC electrolytic treatment in acidic solution) is known, and the surface of the support is appropriately combined with several of these methods to superimpose multiple roughnesses with different wavelengths. Multiple surface roughness structures are formed.

  An anodized film, that is, an aluminum oxide layer is provided on the surface having such multiple roughness, and the aluminum oxide layer is further treated with a developer containing, for example, a silicate to make the surface an aluminosilicate. A hydrophilic surface with good printing performance is formed.

  As described above, since the aluminum grain forms a hydrophilic surface through a number of processes, it is necessary to strictly control and use various conditions in each process in order to obtain stable performance. Much effort is required to stabilize the quality, such as the performance changes depending on the aluminum raw material composition. In addition, an acid or alkali aqueous solution is used for electrolytic surface roughening treatment, anodizing treatment, and hydrophilization treatment, and in particular, a high concentration sulfuric acid aqueous solution of 20 to 40% is generally used for anodizing treatment, etc. It also has safety issues and environmental issues such as waste liquid treatment.

  On the other hand, as a support having a hydrophilic surface for a printing plate material that does not necessarily require electrochemical roughening or anodization, a hydrophilic layer is formed by applying an aqueous silicate solution in which inorganic particles are dispersed on a substrate. Although a method for manufacturing a support characterized by forming is proposed (see, for example, Patent Document 1), it is possible to achieve cost reduction with this method, but multiple roughnesses on the surface can be achieved. The structure cannot be given and the water amount latitude during printing is insufficient, and since the binder is just water glass, it lacks flexibility, has the drawbacks of being easily cracked and easily peeled off, and has a long printing life. It is not satisfactory.

  For the purpose of imparting flexibility to the hydrophilic layer, many studies have been made on a hydrophilic layer in which an organic material and an inorganic material are combined. For example, a hydrophilic layer containing a non-gelatinous hydrophilic (co) polymer or (co) polymer mixture is disclosed (see, for example, Patent Document 2). Specifically, a binder cross-linked with tetramethyl orthosilicate obtained by hydrolyzing a hydrophilic resin such as polyvinyl alcohol, polyacrylamide, or polyacrylic acid is used. By containing an organic material and crosslinking, the toughness of the coating film is greatly improved. However, in such a hydrophilic resin, the hydrophilic group is lost by crosslinking, so that the hydrophilicity of the formed coating film is lowered and is insufficient as a hydrophilic layer for a printing plate.

  In addition, silicate compounds such as sodium silicate, potassium silicate, lithium silicate, hydrophilic resins such as polyacrylic acid, polyvinyl alcohol, and novolac resin, and optionally metal aluminum, metal titanium, aluminum oxide, titanium oxide, indium oxide, A hydrophilic layer containing a powder mainly composed of an inorganic component such as tin oxide or silicon oxide is disclosed (for example, see Patent Document 3). Also in this embodiment, in the hydrophilic resin as described above, the hydrophilic group is lost by crosslinking, so the hydrophilicity of the hydrophilic layer is not satisfactory.

  In particular, in recent years, there has been a printing plate material corresponding to so-called on-press development in which development using a specific chemical solution is unnecessary and a part of the constituent layer of the printing plate material is removed on the printing machine using dampening water or ink. It has been demanded. The hydrophilic layer applied to such an on-press development type printing plate material needs to have even better hydrophilicity because the hydrophilic treatment during development cannot be performed.

  In order to make the printing work environment better, there is a movement to use a fountain solution that does not contain alcohol such as IPA. In order to cope with this point, the hydrophilic layer of the printing plate material has even better hydrophilicity. It has become necessary.

Thus, a technique for an organic-inorganic composite binder applicable to a hydrophilic layer for a printing plate that can achieve both hydrophilicity comparable to that of an aluminum grain and toughness of a coating film has been demanded.
WO97 / 1987 pamphlet (Claims) Japanese Patent Laid-Open No. 11-34526 (Claims) JP 2002-248877 A (Claims)

  An object of the present invention is to form a hydrophilic surface on a substrate by inexpensive coating, and to perform the performance as a printing plate (water amount latitude, resistance to non-image area contamination, resistance to blanket contamination). Etc.) is to provide a printing plate material which is equivalent to or better than the aluminum grain and has sufficient printing durability. Another object of the present invention is to provide a printing method using on-press development and accompanying on-press development.

The above object of the present invention can be achieved by the following configuration.
(Claim 1)
A printing plate material having a constituent layer on a substrate, wherein one of the constituent layers contains the following material A.
Material A: Material selected from polyglycosamine or polyglycosamine derivatives (Claim 2)
The printing plate material according to claim 1, wherein the printing plate material has a hydrophilic layer on a substrate, and the hydrophilic layer contains a material A.
(Claim 3)
2. The printing plate material according to claim 1, wherein an exposed portion has an image forming layer remaining on the substrate, and the image forming layer contains a material A. 3.
(Claim 4)
The printing plate material according to any one of claims 1 to 3, wherein the material A is soluble in an aqueous solution having a pH of 7 or more.
(Claim 5)
The printing layer material according to any one of claims 1 to 4, wherein the constituent layer containing the material A further contains a crosslinking agent.
(Claim 6)
Any of the constituent layers on the base material contains the following material A, and the printing plate material having an image forming layer that can be developed on-machine is exposed imagewise using an infrared laser, and then development is not performed. A printing method characterized in that printing is performed.
Material A: Material selected from polyglycosamine or polyglycosamine derivatives (Claim 7)
The printing method according to claim 6, wherein the material A is soluble in an aqueous solution having a pH of 7 or more.
(Claim 8)
A printing method comprising printing the printing plate material according to any one of claims 1 to 5 without performing development after imagewise exposure using an infrared laser.
(Claim 9)
Infrared laser exposure is performed on a printing machine, The printing method of any one of Claims 6-8 characterized by the above-mentioned.

  According to the present invention, hydrophilic surface formation on a substrate can be performed by inexpensive coating, and performance as a printing plate (water latitude, resistance to non-image area stains, blanket stain resistance, etc.) Is to provide a printing plate material that is equivalent to or better than aluminum grain and has sufficient printing durability. Moreover, the printing method accompanying on-press development using said printing plate material was able to be provided.

  The present invention will be described in more detail. Polyglycosamine is a polysaccharide composed of amino sugars, and chitin, chitosan, colominic acid, polygalactosamine and the like are known. In the present invention, chitin, chitosan and derivatives thereof are preferably used as the material A, and chitosan and chitosan derivatives are particularly preferably used.

  Chitin is an organic compound that is widely distributed in nature as a support for invertebrates such as crustaceans such as crabs and shrimps, spiders, insects, and the like, and exists in large quantities. When chitin is heated with concentrated alkali, it is deacetylated to obtain chitosan having a free amino group. A chitin having a degree of deacetylation of 50% or less may be referred to as chitin, and a chitin having a degree of deacetylation of 50% or more may be referred to as chitosan. Hereinafter, all deacetylated chitin will be referred to as chitosan. .

  Chitosan is a polymer of about 500,000 to 500,000 and has excellent moisturizing ability. Therefore, chitosan is also used as a cosmetic raw material and put into practical use. This moisture retaining property functions as a very good hydrophilicity when used in a printing plate material.

  Chitosan can also be modified with various compounds in the functional group, and derivatives of chitosan modified with various compounds depending on the purpose of use have been widely studied.

  For example, chitosan modified with a compound having a reactive group such as sugar, JP-A-10-130304, JP-A-11-71406, JP-A-11-71407, JP-A-2000-38403, JP-A-2000-212203, JP 2000-256403, JP 2000-256404, JP 2001-240606, JP 2001-337458, WO 00/027889, JP 2002-508020, JP 2002-523528, JP 2002 The chitosan derivative described in -226503 can be mentioned.

  Chitosan is soluble in an acidic aqueous solution because an amino group forms a salt with an acid, but is insoluble in a neutral or alkaline aqueous solution. However, it is also possible to obtain a derivative that is soluble in a neutral or alkaline aqueous solution by modifying the functional group of chitosan with a specific compound.

  For example, by bonding a polyoxyalkylene compound to the amino group of chitosan, the hydrophilicity of chitosan can be further improved, and a derivative that is soluble in neutral or alkaline aqueous solutions can be obtained. Examples of the polyoxyalkylene compound include polyoxyethylene glycol and polyoxyethylene glycol monomethyl ether. The degree of polymerization of the polyoxyalkylene compound is preferably 10 or more, more preferably 18 or more, in order to add water solubility. In order to reduce the influence of thickening of the chitosan derivative aqueous solution and improve the handleability, the degree of polymerization is preferably 300 or less. Moreover, as content of the polyoxyalkylene group in a chitosan derivative, it exists in the range of 40 mass%-90 mass%, since hydrophilicity and water solubility are provided, leaving the characteristic of chitosan, is preferable.

In addition, solubility in neutral or alkaline aqueous solutions can be imparted by binding reducing sugars (monosaccharides, disaccharides, oligosaccharides higher than trisaccharides, etc.) to the amino group of chitosan. Alternatively, the solubility in a neutral or alkaline aqueous solution can also be imparted by oxidizing the CH ₂ OH group of chitosan to a COOX group (X represents any one of H, Na, and K).

  Further, a method of purifying from an acidic aqueous solution of chitosan described in US Pat. No. 5,730,876 using a separation membrane, or an acid ion from an acidic aqueous solution of chitosan described in JP-A-2002-69101. Chitosan which is water-soluble and has a pH of about 6.5 can also be obtained by a method of removing by exchange.

  In the present invention, for example, the material A of the present invention can also be used for surface treatment of aluminum grain which is a base material of a printing plate material.

  However, one preferred embodiment of the present invention includes a printing plate material having a hydrophilic layer on a substrate and the hydrophilic layer containing the material A. By containing the material A, the hydrophilicity of the hydrophilic layer is improved, and the water amount latitude during printing is improved.

  Further, when the material A is contained in the hydrophilic layer in an amount of 0.5 to 3% by mass, there is also an effect that the strength of the hydrophilic layer coating film is hardly lowered even if it is not crosslinked.

  Furthermore, since the amino group of the material A, particularly the amino group of chitosan or chitosan derivative, is rich in reactivity, the hydrophilic layer can be formed into a stronger film by crosslinking the amino group. When the material A is crosslinked, the hydrophilicity is maintained even after crosslinking, unlike the case of crosslinking a hydrophilic resin such as polyvinyl alcohol or polyacrylic acid. Although this reason is not clear, it is considered that an amino group is selectively used for crosslinking and a hydrophilic group such as a hydroxyl group remains.

  It does not specifically limit as a crosslinking agent, The well-known crosslinking agent which can be used by an aqueous system can be used. Specific examples include an active vinyl compound, a carbodiimide compound, an isocyanate compound, a blocked isocyanate compound, and the like, and an active vinyl compound and a carbodiimide compound are particularly preferable.

  As will be described later, since the hydrophilic layer is preferably formed by applying and drying an alkaline aqueous coating solution, the material A is also preferably used as a derivative soluble in an alkaline aqueous solution.

  Examples of the material constituting the hydrophilic layer other than the material A include the following. As the hydrophilic material used for the hydrophilic layer, a metal oxide is preferable.

  The metal oxide preferably contains metal oxide fine particles. Examples thereof include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The form of the metal oxide fine particles may be spherical, needle-like, feather-like, or any other form. The average particle diameter is preferably 3 to 100 nm, and several kinds of metal oxide fine particles having different average particle diameters can be used in combination. The surface of the particles may be surface treated.

  The metal oxide fine particles can be used as a binder by utilizing the film forming property. The decrease in hydrophilicity is less than when an organic binder is used, and it is suitable for use in a hydrophilic layer.

  Among the above, colloidal silica can be preferably used in the present invention. Colloidal silica has the advantage of high film-forming properties even under relatively low temperature drying conditions, and can provide good strength.

  The colloidal silica preferably includes necklace-like colloidal silica, which will be described later, and fine particle colloidal silica having an average particle size of 20 nm or less, and the colloidal silica preferably exhibits alkalinity as a colloidal solution.

  The necklace-like colloidal silica used in the present invention is a general term for an aqueous dispersion of spherical silica whose primary particle diameter is on the order of nm. The necklace-like colloidal silica used in the present invention means “pearl necklace-like” colloidal silica in which spherical colloidal silica having a primary particle diameter of 10 to 50 nm is bonded to a length of 50 to 400 nm. The pearl necklace shape (that is, the pearl necklace shape) means that the image in a state in which the silica particles of colloidal silica are connected and connected has a shape like a pearl necklace. The bond between the silica particles constituting the necklace-shaped colloidal silica is presumed to be —Si—O—Si— in which —SiOH groups present on the surface of the silica particles are dehydrated. Specific examples of the colloidal silica in the form of necklace include “Snowtex-PS” series manufactured by Nissan Chemical Industries, Ltd.

  Product names include “Snowtex-PS-S (average particle size in the connected state is about 110 nm)”, “Snowtex-PS-M (average particle size in the connected state is about 120 nm)” and “Snowtex- PS-L (the average particle size in the connected state is about 170 nm) ", and acidic products corresponding to these are" Snowtex-PS-SO "," Snowtex-PS-MO "and “Snowtex-PS-LO”.

  By adding necklace-like colloidal silica, it becomes possible to maintain the strength while ensuring the porosity of the layer, and it can be preferably used as a porous material for the layer.

  Among these, when “Snowtex PS-S”, “Snowtex PS-M”, and “Snowtex PS-L”, which are alkaline, are used, the strength of the hydrophilic layer is improved and the number of printed sheets is large. However, it is particularly preferable because the occurrence of soiling is suppressed.

  Further, it is known that the colloidal silica has a stronger binding force as the particle diameter is smaller, and it is preferable to use colloidal silica having an average particle diameter of 20 nm or less in the present invention, and more preferably 3 to 15 nm. preferable. In addition, as described above, alkaline colloidal silica is particularly preferable because alkaline colloidal silica has a high effect of suppressing the occurrence of soiling.

  Alkaline colloidal silica having an average particle size within this range includes “Snowtex-20 (particle size 10-20 nm)”, “Snowtex-30 (particle size 10-20 nm)”, “Snowtex” manufactured by Nissan Chemical Co., Ltd. -40 (particle diameter 10-20 nm) "," Snowtex-N (particle diameter 10-20 nm) "," Snowtex-S (particle diameter 8-11 nm) "," Snowtex-XS (particle diameter 4-6 nm) ) ".

  Colloidal silica having an average particle size of 20 nm or less is particularly preferable because it can be further improved in strength while maintaining the porous property of the layer when used in combination with the aforementioned necklace-like colloidal silica.

  The ratio of colloidal silica / necklace-shaped colloidal silica having an average particle diameter of 20 nm or less is preferably 95/5 to 5/95, more preferably 70/30 to 20/80, and still more preferably 60/40 to 30/70.

  The hydrophilic layer of the printing plate material of the present invention preferably contains porous metal oxide particles as a metal oxide. As the porous metal oxide particles, porous silica, porous aluminosilicate particles, or zeolite particles described later can be preferably used.

  The porous silica particles are generally produced by a wet method or a dry method. In the wet method, it can be obtained by drying and pulverizing a gel obtained by neutralizing an aqueous silicate solution, or by pulverizing a precipitate deposited after neutralization. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica. These particles can be controlled in porosity and particle size by adjusting production conditions.

As the porous silica particles, those obtained from a wet gel are particularly preferable.
The porous aluminosilicate particles are produced, for example, by the method described in JP-A-10-71764. That is, amorphous composite particles synthesized by hydrolysis using aluminum alkoxide and silicon alkoxide as main components. The ratio of alumina to silica in the particles can be synthesized in the range of 1: 4 to 4: 1. In addition, those produced as composite particles of three or more components by adding an alkoxide of another metal during production can also be used in the present invention. These composite particles can also control the porosity and particle size by adjusting the production conditions.

  The porosity of the particles is preferably 1.0 ml / g or more in terms of pore volume before dispersion, more preferably 1.2 ml / g or more, and 1.8 to 2.5 ml / g. More preferably, it is as follows.

The pore volume is closely related to the water retention of the coating film. The larger the pore volume, the better the water retention and the less smudged during printing, and the greater the water volume latitude, but greater than 2.5 ml / g. Then, since the particles themselves become very brittle, the durability of the coating film decreases. When the pore volume is less than 1.0 ml / g, it is difficult to stain during printing and the water amount latitude is insufficient.
The particle size is preferably substantially 1 μm or less, and more preferably 0.5 μm or less, in a state where it is contained in the hydrophilic layer (including when crushed during dispersion, for example). If unnecessarily coarse particles are present, porous and steep protrusions are formed on the surface of the hydrophilic layer, and ink tends to remain around the protrusions, which may deteriorate non-image area stains and blanket stains.

  Zeolite is a crystalline aluminosilicate and is a porous body having regular three-dimensional network voids having a pore diameter of 0.3 to 1 nm. The general formula combining natural and synthetic zeolite is expressed as follows:

(M ₁ , M ₂ 1/2) _m (Al _m Si _n O _{2 (m + n)} ) · xH ₂ O
Here, M ₁ and M ₂ are exchangeable cations, and M ₁ is Li ⁺ , Na ⁺ , K ⁺ , Tl ⁺ , Me ₄ N ⁺ (TMA), Et ₄ N ⁺ (TEA), Pr _4. N ⁺ (TPA), C ₇ H ₁₅ N ²⁺ , C ₈ H ₁₆ N ^{+ and the} like, and M ₂ is Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ , C ₈ H ₁₈ N ₂ ^{2. +} Etc. Further, n ≧ m, and the value of m / n, that is, the Al / Si ratio is 1 or less. It can be said that the higher the Al / Si ratio, the higher the polarity because it is considered that there are more solid acid points, and therefore higher hydrophilicity. A preferable Al / Si ratio is 0.4 to 1.0, and more preferably 0.8 to 1.0. x represents an integer.

As the zeolite fine particles used in the present invention, a synthetic zeolite having a stable Al / Si ratio and a relatively sharp particle size distribution is preferable. For example, zeolite A: Na ₁₂ (Al ₁₂ Si ₁₂ O ₄₈ ) 27H ₂ O; Al / Si ratio 1.0, zeolite X: Na ₈₆ (Al ₈₆ Si ₁₀₆ O ₃₈₄ ) • 264H ₂ O; Al / Si ratio 0.811, zeolite Y: Na ₅₆ (Al ₅₆ Si ₁₃₆ O ₃₈₄ ) · 250H ₂ O; Al / Si ratio 0.412 and the like.

  By containing highly hydrophilic porous particles having an Al / Si ratio of 0.4 to 1.0, the hydrophilicity of the hydrophilic layer itself is greatly improved, it is difficult to get dirty during printing, and the water latitude is widened. In addition, the dirt on the fingerprint marks is greatly improved. When the Al / Si ratio is less than 0.4, the hydrophilicity is insufficient, and the effect of improving the performance becomes small.

The particle diameter of the porous inorganic particles is preferably substantially 1 μm or less, and more preferably 0.5 μm or less, when contained in the hydrophilic layer.
In addition, the hydrophilic layer of the printing plate material of the present invention may contain layered clay mineral particles as a metal oxide. The layered mineral particles include kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, sabonite, etc.), clay minerals such as vermiculite, mica (mica), chlorite, hydrotalcite, layered polysilicate ( Kanemite, macatite, ialite, magadiite, kenyaite, etc.). Among them, it is considered that the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The charge density is preferably 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density 0.25 to 0.6; negative charge), vermiculite (charge density 0.6 to 0.9; negative charge) and the like. In particular, synthetic fluoromica is preferable because it can be obtained with stable quality such as particle size. Among the synthetic fluorine mica, those that are swellable are preferable, and those that are free swell are more preferable.

  Also used are intercalation compounds of the above-mentioned layered minerals (pillar crystals, etc.), those subjected to ion exchange treatment, and those subjected to surface treatment (silane coupling treatment, compounding treatment with organic binder, etc.) can do.

  The size of the flat lamellar mineral particles is 20 μm or less in average particle diameter (maximum particle length) in the state of being contained in the layer (including the case where the swelling process and dispersion peeling process have been performed). The average aspect ratio (maximum particle length / particle thickness) is preferably a thin layer of 20 or more, the average particle size is 5 μm or less, the average aspect ratio is more preferably 50 or more, and the average particle size More preferably, the diameter is 1 μm or less and the average aspect ratio is 50 or more. When the particle size is in the above range, the continuity and flexibility in the planar direction, which are the characteristics of the thin layered particles, are imparted to the coating film, and it is difficult for cracks to occur, and a tough coating film can be obtained in a dry state. Moreover, in the coating liquid containing many particulate matters, sedimentation of particulate matter can be suppressed by the thickening effect of the layered clay mineral. If the particle diameter is out of the above range, the effect of suppressing scratches due to scratching may be reduced. Further, when the aspect ratio is less than the above range, the flexibility becomes insufficient, and the effect of suppressing scratches due to scratching may also be reduced.

  The content of the layered mineral particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass based on the entire layer. In particular, swellable synthetic fluorinated mica and smectite are preferable because they are effective even when added in a small amount. The layered mineral particles may be added as a powder to the coating solution, but in order to obtain a good degree of dispersion even with a simple preparation method (no need for a dispersion step such as media dispersion), the layered mineral particles are used alone. It is preferable that the gel swollen in water is prepared and then added to the coating solution.

A silicate aqueous solution can also be used as another additive material in the hydrophilic layer of the present invention. Alkali metal silicates such as silicate Na, silicate K, and silicate Li are preferred, and the SiO ₂ / M ₂ O ratio is in a range where the pH of the entire coating solution does not exceed 13 when silicate is added. It is preferable to select such that the inorganic particles are not dissolved.

  Further, an inorganic polymer or an organic-inorganic hybrid polymer using a metal alkoxide by a so-called sol-gel method can also be used. The formation of an inorganic polymer or an organic-inorganic hybrid polymer by the sol-gel method is described in, for example, “Application of the sol-gel method” (Sakuo Sakuo / Published by Agne Jofusha) or cited in this book. Known methods described in the published literature can be used.

  A hydrophilic organic resin other than the material A may be contained in the hydrophilic layer. Examples of hydrophilic organic resins include polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, and acrylic. Examples thereof include resins such as polymer latex, vinyl polymer latex, polyacrylamide, and polyvinylpyrrolidone.

  In addition, the resin may contain a cationic resin. Examples of the cationic resin include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine or derivatives thereof, and acrylic resins having a tertiary amino group or a quaternary ammonium group. , Diacrylamine and the like. The cationic resin may be added in the form of fine particles. Examples thereof include a cationic microgel described in JP-A-6-161101.

  The hydrophilic layer of the present invention may contain a polysaccharide other than the material A. As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred.

  This is because an effect of forming the surface shape of the hydrophilic layer in a preferable state can be obtained by including the polysaccharide in the hydrophilic layer. This effect has also the raw material A which is a polysaccharide.

The surface of the hydrophilic layer preferably has a concavo-convex structure with a pitch of 0.1 to 50 μm like the aluminum grain of the PS plate, and this concavo-convex improves water retention and image area retention.
Such a concavo-convex structure can be formed by containing an appropriate amount of a filler having an appropriate particle size in the hydrophilic layer, but the above-mentioned alkaline colloidal silica and the above-mentioned water-soluble substance are used in the hydrophilic layer coating solution. It is preferable that a structure having better printing performance can be obtained by containing a polysaccharide and forming a phase separation when the hydrophilic layer is applied and dried.

  The shape of the concavo-convex structure (such as pitch and surface roughness) is the type and amount of alkaline colloidal silica, the type and amount of water-soluble polysaccharides, the type and amount of other additives, the solid content concentration of the coating solution, and the wet film. The thickness and drying conditions can be appropriately controlled.

The pitch of the concavo-convex structure is more preferably 0.2 to 30 μm, and further preferably 0.5 to 20 μm. Further, a concavo-convex structure having a multiple structure in which a concavo-convex structure having a smaller pitch is formed on the concavo-convex structure having a large pitch may be formed.
As surface roughness, 100-1000 nm is preferable by Ra, and 150-600 nm is more preferable.

Moreover, as a film thickness of a hydrophilic layer, it is 0.01-50 micrometers, Preferably it is 0.2-10 micrometers, More preferably, it is 0.5-3 micrometers.
Moreover, the hydrophilic layer (coating solution) of the present invention may contain a water-soluble surfactant for the purpose of improving the coating property. As the surfactant, it is preferable to use a surfactant such as Si, F, or acetylene glycol. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass, based on the entire hydrophilic layer (solid content as the coating solution).

  In addition, the hydrophilic layer of the present invention can contain a phosphate. In the present invention, since the hydrophilic layer coating solution is preferably alkaline, the phosphate is preferably added as trisodium phosphate or disodium hydrogen phosphate. By adding phosphate, the effect of improving the mesh opening at the time of printing can be obtained. The addition amount of phosphate is preferably 0.1 to 5% by mass, and more preferably 0.5 to 2% by mass as an effective amount excluding hydrate.

In the printing plate material of this aspect, as a method of forming an image on the hydrophilic layer, image formation by a known ink jet method or a hot melt transfer method can be applied.
Further, by providing an oleophilic ablation layer having photothermal conversion ability between the hydrophilic layer and the substrate used in the present invention, an ablation type printing plate material capable of forming an image by infrared laser exposure can be obtained. it can.

  A more preferable embodiment is a printing plate material in which an image forming layer containing a hydrophobizing precursor described later is provided on a hydrophilic layer, and a photothermal conversion material described later is included in any of the constituent layers on the substrate. . When the image forming layer is configured to be removable using dampening water or ink on a printing press as described later, a printing plate material that can be developed on the press can be obtained.

Another embodiment of the present invention is a printing plate material having an image forming layer in which an exposed portion remains on the substrate, and the image forming layer contains the material A. it can.
In this embodiment, as a more preferable embodiment, there is an embodiment in which an image forming layer that can be developed on-press on a hydrophilic surface substrate or a hydrophilic layer and the image forming layer contains the material A. Since the image forming layer preferably forms an image by heat generated by exposure with an infrared laser, any of the layers constituting the printing plate material preferably contains a photothermal conversion material described later.

  The effect of the material A in this aspect is an improvement in on-press development property and an improvement in hydrophilicity on the surface of the hydrophilic surface substrate or hydrophilic layer exposed after on-press development. Due to this effect, for example, the hydrophobized precursor particles described later in the image forming layer strongly adhere to the surface of the substrate or the hydrophilic layer by an external force such as a scratch, thereby delaying the developability in on-press development. So-called scratch dirt, which becomes dirt, is also greatly improved.

  Further, the image forming layer in the exposed area can be crosslinked to give image strength in combination with a thermal crosslinking agent such as blocked isocyanate.

  As one of the preferable embodiments of the image forming layer of the present invention, an embodiment in which the image forming layer contains a hydrophobizing precursor can be mentioned. In the present invention, it is preferable to use thermoplastic hydrophobic particles or microcapsules enclosing a hydrophobic substance as the hydrophobizing precursor.

  Examples of the thermoplastic fine particles include heat-fusible fine particles and heat-fusible fine particles described later.

  The heat-meltable fine particles used in the present invention are fine particles formed of a material that has a low viscosity when melted, and is generally classified as a wax, among thermoplastic materials. The physical properties are preferably a softening point of 40 ° C. or higher and 120 ° C. or lower, a melting point of 60 ° C. or higher and 150 ° C. or lower, more preferably a softening point of 40 ° C. or higher and 100 ° C. or lower, and a melting point of 60 ° C. or higher and 120 ° C. or lower. When the melting point is less than 60 ° C., storage stability is a problem, and when the melting point is higher than 300 ° C., ink deposition sensitivity is lowered.

  Usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, fatty acid wax and the like. These have a molecular weight of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups. Furthermore, in order to lower the softening point and improve the workability, these waxes are stearamide, linolenamide, laurylamide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, coconut fatty acid amide. Alternatively, methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide, and the like can be added. Coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, xylene resin, ketone resin, acrylic resin, ionomer, and copolymers of these resins can also be used.

  Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, and fatty acid. Since these materials have a relatively low melting point and a low melt viscosity, highly sensitive image formation can be performed. In addition, since these materials have lubricity, damage when a shearing force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches or the like is improved.

  The heat-meltable fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-meltable fine particles is applied onto the porous hydrophilic layer described later, the heat-meltable fine particles are not removed from the pores of the hydrophilic layer. It becomes easy to enter inside or into the gaps between fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, which may cause scumming. When the average particle size of the heat-meltable fine particles is larger than 10 μm, the resolution is lowered.

  Further, the composition of the heat-meltable fine particles may vary continuously between the inside and the surface layer, or may be coated with a different material.

As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.
As content of the heat-meltable microparticles | fine-particles in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

  Examples of the heat-fusible fine particles of the present invention include thermoplastic hydrophobic polymer fine particles, and there is no specific upper limit for the softening temperature of the polymer fine particles, but the temperature is the decomposition temperature of the polymer fine particles. Lower is preferred. The mass average molecular weight (Mw) of the polymer is preferably in the range of 10,000 to 1,000,000.

  Specific examples of the polymer constituting the polymer particles include, for example, diene (co) polymers such as polypropylene, polybutadiene, polyisoprene and ethylene-butadiene copolymer, styrene-butadiene copolymer, Synthetic rubbers such as methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate- ( N-methylolacrylamide) copolymer, (meth) acrylic acid ester such as polyacrylonitrile, (meth) acrylic acid (co) polymer, polyvinyl acetate, vinyl acetate-vinyl propionate copolymer, vinyl acetate-ethylene copolymer Vinyl etc. of polymers Ester (co) polymer, vinyl acetate - (2-ethylhexyl acrylate) copolymers, polyvinyl chloride, polyvinylidene chloride, polystyrene and copolymers thereof. Of these, (meth) acrylic acid esters, (meth) acrylic acid (co) polymers, vinyl ester (co) polymers, polystyrene, and synthetic rubbers are preferably used.

  The polymer polymer fine particles may be composed of a polymer polymer polymerized by any known method such as emulsion polymerization, suspension polymerization, solution polymerization, and gas phase polymerization. As a method of microparticulating a polymer polymer polymerized by a solution polymerization method or a gas phase polymerization method, a method of spraying a solution in an organic solvent of the polymer polymer into an inert gas and drying to form particles, Examples thereof include a method in which a high molecular weight polymer is dissolved in a water-immiscible organic solvent, this solution is dispersed in water or an aqueous medium, and the organic solvent is distilled off to form fine particles. In any of the methods, a surfactant, such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene glycol, or a water-soluble resin, such as polyvinyl alcohol, is used as a dispersant or stabilizer in polymerization or micronization as necessary. May be used.

  The heat-fusible fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-fusible fine particles is applied onto the porous hydrophilic layer described later, the heat-fusible fine particles It becomes easy to get into the pores or into the gaps between the fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, resulting in fear of soiling. When the average particle size of the heat-fusible fine particles is larger than 10 μm, the resolution is lowered.

Further, the composition of the heat fusible particles may be continuously changed between the inside and the surface layer, or may be coated with a different material.
As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.
As content of the thermoplastic fine particle in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

  Examples of the microcapsules used in the printing plate material of the present invention include microcapsules enclosing a hydrophobic material described in JP-A No. 2002-2135 and JP-A No. 2002-19317.

The microcapsules preferably have an average diameter of 0.1 to 10 μm, more preferably 0.3 to 5 μm, and even more preferably 0.5 to 3 μm.
The thickness of the wall of the microcapsule is preferably 1/100 to 1/5 of the diameter, and more preferably 1/50 to 1/10.

The content of the microcapsule is 5 to 100% by mass of the entire image forming layer, preferably 20 to 95% by mass, and more preferably 40 to 90% by mass.
Known materials and methods can be used as the material for the wall of the microcapsule and the method for producing the microcapsule. For example, known materials and methods described in “New edition microcapsules; production method / property / application thereof” (Takeshi Kondo, Masumi Koishi; published by Sankyo Publishing Co., Ltd.) or cited references are used. Can be used.

  The image forming layer used in the present invention may further contain the following materials.

  The image forming layer can contain a photothermal conversion material described later. In a mode in which a part of the image forming layer is developed on-press, it is preferable to use a photothermal conversion material that is less colored with visible light, and preferably a dye.

  In addition to the material A, the image forming layer can contain a water-soluble resin and a water-dispersible resin. Examples of water-soluble resins and water-dispersible resins include oligosaccharides, polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymers, and methyl methacrylate-butadiene copolymers. Examples thereof include resins such as conjugated diene polymer latex, acrylic polymer latex, vinyl polymer latex, polyacrylic acid, polyacrylate, polyacrylamide, and polyvinylpyrrolidone.

  Of these, oligosaccharides, polysaccharides, polyacrylic acid, polyacrylates (Na salts, etc.), and polyacrylamide are preferred. However, when the material A and polycarboxylic acid are used in combination, gelation occurs. Therefore, when the material A and the material A are used together, it is preferable to use an oligosaccharide.

Examples of the oligosaccharide include raffinose, trehalose, maltose, galactose, sucrose, and lactose, and trehalose is particularly preferable.
As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred.

  The polyacrylic acid, polyacrylic acid, polyacrylate (Na salt, etc.), and polyacrylamide preferably have a molecular weight of 3,000 to 5,000,000, and more preferably 5,000 to 1,000,000.

  The image forming layer can contain a water-soluble surfactant. Surfactants such as Si, F, and acetylene glycol can be used.

  Further, it may contain an acid (phosphoric acid, acetic acid, etc.) or an alkali (sodium hydroxide, silicate, phosphate, etc.) for pH adjustment.

The amount per image forming layer, a 0.01 to 10 g / m ^2, preferably from 0.1 to 3 g / m ^2, more preferably from 0.2 to 2 g / m ^2.

  Examples of photothermal conversion materials include the following materials. General infrared absorbing dyes such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, organic compounds such as phthalocyanine dyes and naphthalocyanine dyes , Azo-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes. Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-1-280750, JP-A-1-293342, JP-A-2-2074, Kaihei 3-26593, JP-A-3-30991, JP-A-3-34891, JP-A-3-36093, JP-A-3-36094, JP-A-3-36095, JP-A-3-42281, JP-A-3-42281 Examples thereof include compounds described in JP-A-3-97589, JP-A-3-103476, and the like. These can be used alone or in combination of two or more.

  JP-A-11-240270, JP-A-11-265062, JP-A-2000-309174, JP-A-2002-49147, JP-A-2001-162965, JP-A-2002-144750, JP-A-2001-219667. The compounds described in (1) can also be preferably used.

Examples of the pigment include carbon, graphite, metal, metal oxide and the like.
As carbon, furnace black or acetylene black is particularly preferable. The particle size (d50) is preferably 100 nm or less, and more preferably 50 nm or less.

  As the graphite, fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less can be used.

  As the metal, any metal can be used as long as the particle diameter is 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less. The shape may be any shape such as a spherical shape, a piece shape, or a needle shape. Colloidal metal fine particles (Ag, Au, etc.) are particularly preferable.

  As the metal oxide, a material that is black in the visible light region, or a material that has conductivity or is a semiconductor can be used.

  Examples of the former include black iron oxide and black composite metal oxides containing two or more metals.

Examples of the latter include Sb-doped SnO ₂ (ATO), Sn-added In ₂ O ₃ (ITO), TiO ₂ , TiO ₂ reduced TiO (titanium oxynitride, generally titanium black), etc. Is mentioned. Further, it is also possible to use those obtained by coating the core _{(BaSO 4, TiO 2, 9Al} 2 O 3 · 2B 2 O, K 2 O · nTiO 2 , etc.) in these metal oxides. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less.

  Among these photothermal conversion materials, black composite metal oxides containing two or more metals are more preferable materials.

The black iron oxide (Fe ₃ O ₄ ) is preferably particles having an average particle diameter of 0.01 to 1 μm and an acicular ratio (major axis diameter / minor axis diameter) of 1 to 1.5. It is preferably substantially spherical (acicular ratio 1) or has an octahedral shape (acicular ratio about 1.4).
Examples of such black iron oxide particles include TAROX series manufactured by Titanium Industry Co., Ltd. As the spherical particles, BL-100 (particle diameter 0.2 to 0.6 μm), BL-500 (particle diameter 0.3 to 1.0 μm), or the like can be preferably used. Further, as octahedral shaped particles, ABL-203 (particle size 0.4 to 0.5 μm), ABL-204 (particle size 0.3 to 0.4 μm), ABL-205 (particle size 0.2 to 0) .3 μm), ABL-207 (particle size: 0.2 μm) and the like can be preferably used.

Furthermore, particles whose surface is coated with an inorganic substance such as SiO ₂ can also be preferably used. As such particles, spherical particles coated with SiO ₂ : BL-200 (particle size 0.2 to 0) .3 μm), octahedral shaped particles: ABL-207A (particle size 0.2 μm).

  Specifically, the black composite metal oxide is a composite metal oxide composed of two or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sb, and Ba. . These are disclosed by methods disclosed in JP-A-8-27393, JP-A-9-25126, JP-A-9-237570, JP-A-9-241529, JP-A-10-231441, and the like. Can be manufactured.

  The composite metal oxide used in the present invention is particularly preferably a Cu-Cr-Mn-based or Cu-Fe-Mn-based composite metal oxide. In the case of a Cu—Cr—Mn system, it is preferable to perform the treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, they have good photothermal conversion efficiency.

  These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount is obtained. Better. However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better. Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste). An average primary particle size of less than 0.01 is not preferable because dispersion becomes difficult. A dispersing agent can be appropriately used for the dispersion. The addition amount of the dispersant is preferably 0.01 to 5% by mass, and more preferably 0.1 to 2% by mass with respect to the composite metal oxide particles.

  A protective layer may be provided as an upper layer of the image forming layer. As the material used for the protective layer, the material A, the above-mentioned water-soluble resin, and water-dispersible resin can be preferably used.

  Further, hydrophilic overcoat layers described in JP-A Nos. 2002-19318 and 2002-86948 can also be preferably used.

The amount per the protective layer is 0.01 to 10 g / m ^2, preferably from 0.1 to 3 g / m ^2, more preferably from 0.2 to 2 g / m ^2.

  As a base material, the well-known material used as a board | substrate of a printing plate can be used. For example, a metal plate, a plastic film, paper treated with a polyolefin, a composite base material obtained by appropriately bonding the above materials, and the like can be given. The thickness of the base material is not particularly limited as long as it can be attached to a printing press, but a thickness of 50 to 500 μm is generally easy to handle.

  Examples of the metal plate include iron, stainless steel, and aluminum. Aluminum is particularly preferable from the relationship between specific gravity and rigidity. The aluminum plate is usually used after degreasing with an alkali, an acid, a solvent or the like in order to remove oil used during rolling and winding existing on the surface. As the degreasing treatment, degreasing with an alkaline aqueous solution is particularly preferable. Moreover, in order to improve adhesiveness with a coating layer, it is preferable to perform an easy adhesion process or undercoat layer application | coating to an application surface. For example, a method of dipping in a liquid containing a coupling agent such as a silicate or a silane coupling agent or applying a liquid, followed by sufficient drying can be used. Anodizing treatment is also considered as a kind of easy adhesion treatment and can be used. Moreover, it can also use combining an anodizing process and the said immersion or application | coating process. Moreover, the aluminum base material roughened by the well-known method, what is called an aluminum grain can also be used as a base material which has a hydrophilic surface.

  Examples of the plastic film include polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polycarbonate, polysulfone, polyphenylene oxide, and cellulose esters.

  As the substrate used in the present invention, polyethylene terephthalate and polyethylene naphthalate are particularly preferable. These plastic films are preferably subjected to easy adhesion treatment or undercoat layer coating on the coated surface in order to improve adhesion with the coated layer. Examples of the easy adhesion treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. Examples of the undercoat layer include a layer containing gelatin or latex. The undercoat layer may contain an organic or inorganic known conductive material.

  In addition, for the purpose of controlling the slipperiness of the back surface (for example, reducing the friction coefficient with the plate cylinder surface), a substrate provided with a back surface coating layer can also be preferably used.

  The present invention also provides a printing plate material containing a material A selected from polyglycosamine or a derivative of polyglycosamine, and having an image forming layer that can be developed on-press, on any of the constituent layers on the substrate. A printing method is characterized in that after imagewise exposure using an infrared laser, printing is performed without development.

  As described above, by including the material A in any of the constituent layers, various characteristics of the on-press development type printing plate material can be greatly improved.

On-press development is performed using dampening water or ink in the manner described below. The fountain solution used for printing is generally acidic, but it is preferable that the material A is soluble in an aqueous solution having a pH of 7 or more because the range of adaptation to the fountain solution composition is widened.
Infrared laser exposure can also be performed on a printing press.

  The image forming layer of the printing plate material of the infrared laser heat melting / fusion method, which is a preferred embodiment of the printing plate material of the present invention, has an infrared laser exposed portion becomes an oleophilic image portion, and an unexposed portion layer is removed. It becomes a non-image part. The unexposed portion can be removed by washing with water, but it is also possible to perform so-called on-press development, in which the unexposed portion is removed using dampening water and / or ink on a printing press.

The removal of the unexposed part of the image forming layer on the printing machine can be performed by contacting a watering roller or an ink roller while rotating the plate cylinder. The various sequences can be performed. In that case, the water amount may be adjusted by increasing or decreasing the amount of dampening water required for printing, and the water amount adjustment may be divided into multiple stages or steplessly. You may change it to.
(1) As a sequence for starting printing, a watering roller is brought into contact with the plate cylinder to make one to several dozen rotations, then an ink roller is brought into contact with the plate cylinder to make one to several dozen rotations, and then Start printing.
(2) As a sequence for starting printing, an ink roller is contacted to rotate the plate cylinder 1 to several tens of turns, then a watering roller is contacted to rotate the plate cylinder 1 to tens of rotations, Start printing.
(3) As a sequence for starting printing, the watering roller and the ink roller are brought into contact with each other substantially simultaneously to rotate the plate cylinder 1 to several tens of times, and then printing is started.

Base material 1
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm was immersed in a 1% by mass sodium hydroxide aqueous solution at 50 ° C., dissolved so that the dissolved amount became 2 g / m ² , and washed with water. Then, it was immersed in 0.1 mass% hydrochloric acid aqueous solution at 25 ° C. for 30 seconds, neutralized, and then washed with water.
Next, this aluminum plate was subjected to an electrolytic surface roughening treatment with an electrolytic solution containing hydrochloric acid 10 g / L and aluminum 0.5 g / L using a sine wave alternating current and a peak current density of 50 A / dm ^2. It was. The distance between the electrode and the sample surface at this time was 10 mm. Perform electrolytic graining treatment is divided into 12 times, and the quantity of electricity used in one treatment (at a positive polarity) as the 40C / dm ^2, treatment quantity of electricity 480C / dm ² in total (at a positive polarity). In addition, a rest period of 5 seconds was provided between each surface roughening treatment.

After electrolytic surface roughening, it is immersed in a 1% by weight sodium hydroxide aqueous solution kept at 50 ° C. and etched so that the amount of dissolution including the smut of the roughened surface becomes 1.2 g / m ^2. Then, it was washed with water, then immersed in a 10% aqueous sulfuric acid solution maintained at 25 ° C. for 10 seconds, neutralized, and then washed with water. Next, anodization was performed in a 20% sulfuric acid aqueous solution so that the amount of electricity was 150 C / dm ² under a constant voltage condition of 20 V, followed by washing with water.

  Next, after squeezing the surface water after washing with water, it was immersed in a 1% by mass sodium dihydrogen phosphate aqueous solution maintained at 70 ° C. for 30 seconds, washed with water, dried at 80 ° C. for 5 minutes, Got. Ra of the substrate 1 was 460 nm (measured at 40 times using RST Plus manufactured by WYKO).

Base material 2
A biaxially stretched polyester film film having a thickness of 175 μm was subjected to a corona discharge treatment of 8 W / m ² · min. Then, as shown in Table 4, the following undercoat coating solution a was applied to one surface as a dry film. After coating to a thickness of 0.8 μm, the undercoating liquid b was applied to a dry film thickness of 0.1 μm while performing corona discharge treatment (8 W / m ² · min), each at 180 ° C. for 4 minutes. Dried (undercoating surface A). Also, after coating the following undercoat coating solution c on the opposite side so as to have a dry film thickness of 0.8 μm, the undercoat coating solution d is dried film thickness 1 while performing corona discharge treatment (8 W / m ² · min). The coating was applied to a thickness of 0.0 μm and dried at 180 ° C. for 4 minutes (undercoating surface B). The surface electrical resistance at 25 ° C. and 25% RH after coating was 108Ω. Thus, the base material 2 which formed the undercoat layer on both surfaces was obtained.

<< Undercoat coating liquid a >>
Styrene / glycidyl methacrylate / butyl acrylate = 60/39/1 terpolymer copolymer latex (Tg = 75 ° C.) (based on solid content) 6.3%
Styrene / glycidyl methacrylate / butyl acrylate = 20/40/40 terpolymer latex 1.6%
Anionic surfactant S-1 0.1%
Water 92.0%
<< Undercoat coating liquid b >>
Gelatin 1%
Anionic surfactant S-1 0.05%
Hardener H-1 0.02%
Matting agent (silica, average particle size 3.5 μm) 0.02%
Antifungal agent F-1 0.01%
Water 98.9%

<< Undercoat coating liquid c >>
Styrene / glycidyl methacrylate / butyl acrylate = 20/40/40 terpolymer latex (based on solid content) 0.4%
Styrene / glycidyl methacrylate / butyl acrylate / acetoacetoxyethyl methacrylate = 39/40/20/1 quaternary copolymer latex 7.6%
Anionic surfactant S-1 0.1%
Water 91.9%
<< Undercoat coating liquid d >>
Conductive composition of component d-1 / component d-2 / component d-3 = 66/31/1 6.4%
Hardener H-2 0.7%
Anionic surfactant S-1 0.07%
Matting agent (silica, average particle size 3.5 μm) 0.03%
92.8% water
Component d-1;
An anionic polymer compound comprising a copolymer of sodium styrenesulfonate / maleic acid = 50/50; component d-2;
Three-component copolymer latex consisting of styrene / glycidyl methacrylate / butyl acrylate = 40/40/20 component d-3;
Polymeric activator comprising styrene / sodium isoprenesulfonate = 80/20

Example 1
Synthesis of water-soluble chitosan derivative A water-soluble chitosan derivative in which a polyoxyalkylene group was bonded to the nitrogen atom of chitosan was synthesized using the method described in JP-A-11-71406.

  Chitosan having a number average molecular weight of 30,000 and a deacetylation degree of 86% was used, and PEG (PEG # 4000, Mw: 3000, manufactured by Wako Pure Chemical Industries, Ltd.) was used as polyoxyalkylene. The content of the polyoxyethylene group in the obtained water-soluble chitosan derivative was 60% by mass.

Preparation of printing plate material [Printing plate material 1]
Each material having the following composition was sufficiently stirred and mixed, and then filtered to prepare a coating solution for the image forming layer (1) having a solid content of 10% by mass.

The image forming layer coating solution (1) was applied onto the substrate 1 using a wire bar so that the dry weight was 0.4 g / m ^2, and dried at 55 ° C. for 1 minute.

  Next, each material having the following composition was sufficiently stirred and mixed, and then filtered to prepare a protective layer coating solution having a solid content of 5% by mass.

Next, the protective layer coating solution was applied onto the image forming layer using a wire bar so that the dry weight was 0.4 g / m ² and dried at 55 ° C. for 1 minute. Further, this was subjected to an aging treatment at 40 ° C. for 48 hours to obtain a printing plate material 1.

[Preparation of printing plate material 2]
Printing plate material 2 was obtained in the same manner as printing plate material 1, except that the image forming layer (1) coating solution was changed to the image forming layer (2) coating solution having the following composition.

[Preparation of printing plate material 3]
Printing plate material 3 was obtained in the same manner as printing plate material 1 except that the image forming layer (1) coating solution was changed to an image forming layer (3) coating solution having the following composition.

[Preparation of printing plate material 4]
A printing plate material 4 was obtained in the same manner as the printing plate material 1 except that the coating solution for the image forming layer (1) was changed to the coating solution for the image forming layer (4) having the following composition.

Image formation by infrared laser exposure The printing plate material was wound around an exposure drum and fixed. For the exposure, a laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm was used, an exposure energy was 300 mJ / cm ² , and an image was formed at 2400 dpi and 175 lines. The exposed image includes a solid image and a 1 to 99% halftone dot image.

Printing method 1
Printing machine: DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd., coated paper, dampening solution: Astro Mark 3 (manufactured by Nikken Chemical Laboratory) 2% by mass, ink (TK High Unity Red, manufactured by Toyo Ink Co., Ltd.) Used to print. The printing plate material was attached to the plate cylinder as it was after exposure, and printed using the same printing sequence as the PS plate.

Printing method 2
Printing was performed in the same manner except that the ink in the printing method 1 was changed to soybean oil ink (TK High Unity SOY Red manufactured by Toyo Ink Co., Ltd.).

Printing evaluation [On-press developability]
For each printing plate material, the number of sheets printed from the start of printing was determined for completion of on-press development. The on-machine development end index is that the non-image area is not smudged on the printed material, the density of the solid image area is 1.6 or more (measured in the M mode using Macbeth RD918), and 95 % Halftone image is open. The results of printing methods 1 and 2 are shown in Table 6.

[Scratch dirt evaluation]
After exposure, the non-image area of each printing plate material before printing was scratched by changing the load using 0.3 mmφ sapphire as a stylus with a HEIDON tester. The load was changed from 25 g to 150 g in increments of 25 g. The maximum load at which scratches could not be confirmed as dirt on the 100th printed material from the start of printing evaluation was evaluated and is shown in Table 6.

  From Table 6, it can be seen that the printing plate material of the present invention has good on-press developability and scratch resistance regardless of the type of ink.

Example 2
Preparation of printing plate material [Printing plate material 5]
Printing plate material 5 was obtained in the same manner as printing plate material 1, except that the image forming layer (1) coating solution was changed to the image forming layer (5) coating solution having the following composition.

[Printing plate material 6]
Printing plate material 6 was obtained in the same manner as printing plate material 1, except that the image forming layer (1) coating solution was changed to an image forming layer (6) coating solution having the following composition.

  Image formation by infrared laser exposure was performed in the same manner as in Example 1.

Printing method 3
Printing machine: DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd., high quality paper (Shiraoi), dampening water: 2% by mass of Astro Mark 3 (manufactured by Nikken Chemical Laboratories), ink (TK High manufactured by Toyo Ink Co., Ltd.) Printing was performed using Unity Red. The printing plate material was attached to the plate cylinder as it was after exposure, and printed using the same printing sequence as the PS plate.

Printing evaluation [Evaluation of printing durability]
Printing up to 20,000 sheets was performed, and the number of printed sheets when a 3% halftone image started to be missing was used as an index of printing durability. The results are shown in Table 9.

  From Table 9, it can be seen that the printing plate material of the present invention has good printing durability.

Example 3
Preparation of printing plate material [Printing plate material 7]
A material having the following composition was sufficiently stirred and mixed using a homogenizer, and then filtered to prepare coating solutions for hydrophilic layers (1) to (6) having a solid content of 15% by mass.

The coating liquid of the hydrophilic layer (1) is applied onto the undercoat surface A of the substrate 2 using a wire bar so that the applied amount after drying is 1.5 g / m ^2, and at 100 ° C. for 3 minutes. Dried. Next, an aging treatment at 60 ° C. for 72 hours was performed.

Next, after sufficiently stirring and mixing the materials having the following composition, the mixture was filtered to obtain a coating solution for the image forming layer (7) having a solid content of 10% by mass. Next, the coating solution for the image forming layer (7) was applied onto the hydrophilic layer using a wire bar so that the applied amount after drying was 0.6 g / m ² and dried at 55 ° C. for 3 minutes. . Next, an aging treatment at 40 ° C. for 24 hours was performed to obtain a printing plate material 7.

  A printing plate material 8 was obtained in the same manner as the printing plate material 7 except that the coating solution for the hydrophilic layer (2) was used. Using the coating liquids of the hydrophilic layers (3), (4), (5), and (6), printing plate materials 9, 10, 11, and 12 were obtained in the same manner as described above.

  Image formation by infrared laser exposure was performed in the same manner as in Example 1. All the printing plate materials had good exposure and visibility.

Printing Method Printing was performed in the same manner as in Example 2.

Printing evaluation [Earth dirt evaluation]
The printed material was sampled from the 100th sheet to the 2500th sheet after printing, and every 2000th sheet to the 20000th sheet, and the degree of background smearing in the non-image area was evaluated. The results are shown in Table 12. In the evaluation, it was distinguished from point-like stains caused by non-image part shaving described later. In addition, the symbol in a table | surface has shown the following evaluation result.

○: No soiling △: Slightly soiled ×: Grounding [Evaluation of printing durability: Non-image area]
Separately from the evaluation of background stains, dot-like stains caused by scraping of non-image areas with paper dust were evaluated. The number of printed sheets at the time when two or more spot-like stains were observed in an area of 10 cm × 10 cm was used as an index of printing durability, and the results are shown in Table 12.

[Evaluation of printing durability: Image area]
The number of printed sheets at the time when the 3% halftone dot image started to be missing was used as an index of printing durability, and the results are shown in Table 12.

  As can be seen from Table 12, the printing plate material of the present invention has good printing durability in both the image area and the non-image area without causing soiling.

Claims (9)

A printing plate material having a constituent layer on a substrate, wherein one of the constituent layers contains the following material A.
Material A: Material selected from polyglycosamine or polyglycosamine derivatives The printing plate material according to claim 1, wherein the printing plate material has a hydrophilic layer on a substrate, and the hydrophilic layer contains a material A. 2. The printing plate material according to claim 1, wherein an exposed portion has an image forming layer remaining on the substrate, and the image forming layer contains a material A. 3. The printing plate material according to any one of claims 1 to 3, wherein the material A is soluble in an aqueous solution having a pH of 7 or more. The printing layer material according to any one of claims 1 to 4, wherein the constituent layer containing the material A further contains a crosslinking agent. Any of the constituent layers on the base material contains the following material A, and the printing plate material having an image forming layer that can be developed on-machine is exposed imagewise using an infrared laser, and then development is not performed. A printing method characterized in that printing is performed.
Material A: Material selected from polyglycosamine or polyglycosamine derivatives The printing method according to claim 6, wherein the material A is soluble in an aqueous solution having a pH of 7 or more. A printing method comprising printing the printing plate material according to any one of claims 1 to 5 without performing development after imagewise exposure using an infrared laser. Infrared laser exposure is performed on a printing machine, The printing method of any one of Claims 6-8 characterized by the above-mentioned.