DESCRIPTION
WATERLESS PRINTING PLATE PRECURSOR, AND METHOD FOR
MANUFACTURING PRINTED MATTER USING WATERLESS PRINTING
PLATE
5
TECHNICAL FIELD
[0001]
The present invention relates to a waterless printing plate precursor and a
method of producing a printed material using a waterless printing plate by UV 10 printing.
BACKGROUND ART
[0002]
As a printing method using a lithographic printing plate, a wet printing
method, wherein a thin water layer is formed on the plate surface prior to printing to 15 repel ink, and a waterless printing method, wherein silicone rubber is used instead of
water to repel ink, are available.
[0003]
Oil-based printing using oil-based ink (oxidative polymerization type ink)
has been usually employed in both methods. Unfortunately, since drying of 20 oil-based ink is time-consuming, it is necessary to transfer a printed material to a
drying space for air drying. Therefore, reduction of production period or delivery
period has been limited. In addition, in the case of heal drying that requires a
large-scale system, energy cost increases, which is problematic.
[0004]
25 For the above reasons, a UV printing method using UV ink wherein ink
curing is instantly carried out via UV irradiation has been suggested for wet printing
for reduction of delivery period/cost-saving (Patent Document 1). However, it is

2
known that when wet printing is conducted on non-absorbable materials such as plastics sheets and surface-treated papers, preparation of dampening water is more difficult than wet printing on ordinary papers. In addition, UV ink is often used for food packaging, etc. As dampening water is used for wet printing, dampening 5 water components may partially set off from the surface of a printed material to the backside of a printed material placed thereon while the printed materials are stacked for storage. This has been problematic because a food is brought into direct contact with the backside. [0005]
10 Meanwhile, since no dampening water is used for waterless printing, such
problem would not occur in principle. The concept of waterless printing is that a component having low polarity such as hydrocarbon in an ink is incorporated into an ink repellent layer in non-imaging areas, the ink repellent layer is pressurized during printing so that the component having low polarity is pushed out, and a liquid film of
15 the component having low polarity is formed on the surface of the ink repellent layer, thereby removing/repelling ink. PRIOR ART REFERENCES PATENT DOCUMENTS [0006]
20 Patent Document 1: Japanese Patent Application Laid-Open Publication No.
2011-225751.
DISCLOSURE OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION [0007]
25 However, in the case of waterless printing, an ink such as UV ink containing
a small amount of or no component having low polarity is likely to adhere to non-imaging areas. Therefore, the type of available ink is limited. It is also

3
problematic that when tiie printing environment temperature increases, ink starts to
adhere to non-imaging areas, thereby making impossible to maintain the ink
repelling effects.
[0008]
5 As measures for removing these drawbacks of the prior art, an object of the
present invention is to provide a waterless lithographic printing plate precursor that
sufficiently repels ink sucii as an UV ink, which tends to adhere to non-imaging areas,
and maintains its repelling effects, and a printing method using a waterless
lithographic printing piate obtained from the waterless lithographic printing plate 10 precursor.
MEANS FOR SOLVING THE PROBLEMS
[0009]
The printing plate of the present invention has the following constituent
features.
15 (I) A lithographic printing plate precursor comprising at least a heat sensitive
layer and an ink repellent layer, wherein the ink repellent layer contains an ink
repellent liquid, the ink repellent liquid having a boiling point of not less than 150°C
at 1 atmospheric pressure.
The following are preferable embodiments of the printing plate.
20 (2) The lithographic printing piate precursor according to that described above,
wherein the liquid has a surface tension of from 15 mN/m to 30 mN/m at 25°C.
(3) The lithographic printing plate precursors according to any one of those
described above, wherein the ink repellent layer contains the liquid in an amount of
from 10% by mass to 30% by mass.
25 (4) The lithographic printing plate precursors according to any one of those
described above, wherein the heat sensitive layer contains a novolak resin.
(5) The lithographic printing plate precursor according to one described above,

4
wherein the heat sensitive layer contains from 20% by mass to 95% by mass of the novolak resin.
(6) The lithographic printing plate precursors according to any one of those
described above, wherein the heat sensitive layer contains an organic complex
5 compound.
(7) The lithographic printing plate precursors according to any one of those described above, wherein the heat sensitive layer contains the novolak resin and the organic complex compound at a mass ratio of from 2 to 6.
(8) The lithographic printing plate precursors according to any one of those
10 described above, which has a plate surface elastic modulus of from 4 MPa to 12 MPa when a load of 1400 N/m2 is applied to the surface thereof.
(9) A lithographic printing plate, which is obtained by the steps of:
exposing the lithographic printing plate according to any one of those
described above to light based on an image; and
15 developing the exposed lithographic printing plate precursor and removing
the ink repellent layer. [0010]
A method of producing a lithographic printing plate of the invention and preferable embodiments thereof are described below. 20 (10) A method of producing a lithographic printing plate, comprising the steps of:
exposing the lithographic printing plate precursor according to any one of those described above to light based on an image; and
developing the exposed lithographic printing plate precursor to remove the 25 ink repellent layer.
(11) A method of producing a printed material, comprising the steps of:
allowing an ink to adhere to the surface of the lithographic printing plate

5
according to any one of those described above; and
transferring the ink directly or via a blanket to a printing substrate.
(12) The method of producing the printed material according to that described
above, further comprising a step of irradiating the ink transferred to the printing
5 substrate with an active energy ray. [0011]
In addition, a method of producing a printing plate of the invention and preferable embodiments thereof are described below.
(13) A method of producing a printed material, comprising the step of
10 transferring an ink to a printing substrate using a lithographic printing plate and then
irradiating the printing substrate with ultraviolet light,
wherein the lithographic printing plate is obtained by the steps of: exposing
a lithographic printing plate precursor comprising a heat sensitive layer and an ink
repellent layer to light in accordance with an image; and developing the exposed 15 lithographic printing plate precursor to remove the ink repellent layer, and
wherein the lithographic printing plate precursor comprises at least an ink
repellent layer on a substrate, an ink repellent liquid contained in the ink repellent
layer has a surface tension of 30 mN/m or less, and the ink contains from 10% by
mass to 50% by mass of a photosensitive component. 20 (14) The method of producing a printed material according to that described
above, wherein the liquid has a boiling point of 150°C or more at 1 atmospheric
pressure.
(1 5) The method of producing a printed material according to any one of those
described above, wherein the liquid is of a silicone material. 25 (16) The method of producing a printed material according to any one of those
described above, wherein the ink repellent layer confains from 10% by mass to 25%
by mass of the liquid.

6
(17) The method of producing a printed material according to any one of those
described above, wherein the ink contains from 0.5% by mass to 15% by mass of
aery late ester or methacrylate ester having a linear-chain alkyl group.
EFFECT OF THE INVENTION
[0012]
According to the present invention, it is possible to obtain a waterless
lithographic printing plate precursor that sufficiently repels ink such as an UV ink,
which tends to adhere to non-imaging areas of a waterless lithographic printing plate.
and maintains its repelling effects.
BEST MODE FOR CARRYING OUT THE INVENTION
[0013]
Next described will be the waterless lithographic printing plate precursor of the invention. [0014]
The waterless lithographic printing plate precursor of the invention is a lithographic printing plate precursor having at least a heat sensitive layer and an ink repellent layer, the ink repellent layer containing an ink repellent liquid, and the ink repellent liquid having a boiling point of not less than 150°C at 1 atmospheric pressure. [0015]
Here, the ink repellent liquid is preferably a liquid that prevents an ink to adhere to the ink repellent layer when the liquid is present on the surface of the ink repellent layer in a state of lacking the liquid. It is considered that the ink repellent liquid prevents the adhesion to the ink repellent layer by forming a thin liquid film covering the surface of the ink repellent layer. [0016]
The waterless lithographic printing plate precursor of the invention has a

7
substrate, if necessary. When it has a substrate, it has at least a heat sensitive layer and an ink repellent layer on or above the substrate. Either a heat sensitive layer or an ink repellent layer may be disposed close to a substrate. However, it is preferable that a substrate, a heat sensitive layer, and an ink repellent layer be disposed in that order. [0017]
Examples of a substrate that can be used in the present invention include known papers, metals, glass, and films, which are conventionally used as substrates for printing plates and have few dimensional changes during printing. Specific examples include paper, plastic (e.g., polyethylene, polypropylene, or polystyrene) laminated paper, aluminium (including aluminium alloys), zinc, copper or other such metal sheet, glass pJates of soda lime, quartz, and the like, silicon wafer, films of plastics material, for example cellulose acetate, polyethylene terephlhalate, polyethylene, polyester, polyamide, polyimide, polystyrene, polypropylene, polycarbonate or polyvinyl acetai, and also paper or plastics film laminated with, or with a vapor deposited coating of, an aforesaid metal. Plastic films may be transparent or opaque. From the viewpoint of ease of proofing, opaque plastic films are preferable. [0018]
Among these substrates, aluminum plates have few dimensional changes, and are inexpensive, and therefore are particularly preferable. Again, the polyethylene terephthalate films are also favorable as substrates for short-run printing. [0019]
Substrate thickness is not particularly limited. The thickness corresponding to a press used for lithographic printing may be selected. [0020]

8
A heat sensitive layer that can be preferably used in the invention will be described below. It is preferable for a heat sensitive layer to function to convert laser beam used for drawing to heat (light-to-heat conversion) so that at least the surface of the heat sensitive layer is degraded by the generated heat, thereby 5 increasing solubility in a developer or reduction of adhesion to the ink repellent layer. Such heat sensitive layer may contain the following composition or the like.
(A) A composition containing an active hydrogen-containing polymer, a crosslinker,
and a light-to-heat converting substance
(B) A composition containing an active hydrogen-containing polymer, an organic
10 complex compound, and a light-to-heat converting substance.
[0021]
The heat sensitive layer can be prepared by coating and drying a solution or dispersion containing such composition. Drying may be conducted at ordinary temperature or by heating. When the heat sensitive layer prepared above is
15 irradiated with laser beam, the crosslinked structure formed with an active hydrogen-containing polymer and a crosslinker in the composition (A) or the crosslinked structure formed with the polymer and an organic complex compound in the composition (B) is degraded by heat generated from the light-to-heat converting substance.
20 [0022]
An example of an active hydrogen-containing polymer preferably used for a heat sensitive layer in the present invention is a polymer with a structural unit having active hydrogen. Examples of a structural unit having active hydrogen include -OH, -SII, -NH2, -NH-, -CO-NH2, -CO-NH-, -OC(=0)-NH-, -NH-CO-NH-, -CO-OH,
25 -CS-OH, -CO-SH, -CS-SH, -SO3M, -PO3H2, -S02-NH2, -SO2-NH-, and -CO-CH2-CO-. [0023]

9
Examples of an active hydrogen-containing polymer that can be used for the compositions (A) and (B) are as follows:
homopolymers or copolymers of carboxyl group-containing monomers such as (meth)acrylate, homopolymers or copolymers of (meth)acrylate ester having a 5 hydroxy! group such as hydroxyethyl(meth)acryiate or
2-hydroxypropyI(meth)acrylate, homopolymers or copolymers of N-aikyl(meth)acrylamide or (meth)acrylamide, homopolymers or copolymers of reactants of amines and (meth)glycidyl acrylate or allyl glycidyl, and homopolymers or copolymers of p-hydroxyslyrene or vinyl alcohol, which are homopolymers or
10 copolymers of active hydrogen-containing ethylene-unsaturated monomers
(copolymerized monomer components may be other active hydrogen-containing ethylene-unsaturated monomers or active hydrogen-free ethylene-unsaturated monomers). [0024]
15 Another example of a polymer with a structural unit having active hydrogen
is a polymer with a structural unit having active hydrogen on the main chain. Examples of such polymer include polyurethanes, polyureas, polyamides, epoxy resins, polyalkylenimines, novolak resins, resole resins, and cellulose derivatives. Of these, two or more polymers may be contained. Of these, alcohol hydroxy!
20 group-, phenol hydroxyl group-, or carboxyl group-containing polymers are
preferable, phenol hydroxyl group-containing polymers (e.g., homopolymers or copolymers of p-hydroxystyrene, novolak resins, or resole resins) are more preferable, and novolak resins are further preferable. Examples of novolak resins include phenol novolak resins and cresol novolak resins.
25 [0025]
The content of an active hydrogen-containing polymer is preferably 20% by mass or more and more preferably 30% by mass or more in fhe heat sensitive layer in

10
order to degrade the surface of the heat sensitive layer by heat or cause the heat sensitive layer to be likely to be dissolved in a developer, thereby promoting development. In addition, it is preferably 95% by mass or less and more preferably 80% by mass or less in terms of toughness of the heat sensitive layer. [0026]
It is also preferable for the heat sensitive layer to contain active hydrogen-free polymer capable of forming a film (hereafter referred to as "other polymer X") as well as an active hydrogen-containing polymer. [0027]
Examples of other polymer X include homopolymers or copolymers of (meth)acrylate esters such as polymethyl(meth)acrylate, polybutyl(meth)acrylate, etc.. homopolymers or copolymers of styrene-based monomers such as polystyrene, a-methylstyrene, etc., various synthetic rubbers of isoprene, styrene-butadiene, etc., homopolymers of vinyl esters such as polyvinyl acetate, etc., copolymers of vinyl acetate-vinyl chloride, etc., and various condensate polymers of polyester, polycarbonate, etc. [0028]
The total content of other polymers X is preferably 5% by mass or more and more preferably 10% by mass or more in the heat sensitive layer in order to improve coating characteristic of the heat sensitive layer composition solution. In order to achieve highly fine image reproducibility, the total content of other polymers X is preferably 50% by mass or less and more preferably 30% by mass or less with respect to the total solid content of the heat sensitive layer. [0029]
An example of a crosslinker contained in the composition (A) in the heat sensitive layer is a multifunctional compound having a plurality of functional groups having reactivity to active hydrogen of the above polymers. Examples of the

li
crosslinker include multifunctional isocyanate, multifunctional blocked isocyanate, multifunctional epoxy compounds, multifunctional (meth)acrylate compounds, multifunctional aldehydes, multifunctional mercapto compounds, multifunctional alkoxysilyl compounds, multifunctional amine compounds, multifunctional 5 carboxylic acids, multifunctional vinyl compounds, multifunctional diazonium salts, multifunctional azide compounds, and hydrazine. [0030]
An organic complex compound contained in the composition (B) in the heat sensitive layer comprises a metal and an organic compound. This compound
10 functions as a crosslinker for active hydrogen-containing polymers. The heat
sensitive layer may further contain the above crosslinker. Examples of such organic complex compound include organic complex salts in which an organic ligand is coordinate-bonded to a metal, organic inorganic complex salts in which an organic ligand and an inorganic ligand are coordinate-bonded to a metal, and metal alkoxides
15 in which a metal and an organic molecule are covalent-bonded via oxygen. Of these, a metal chelate compound having a donor atom with two or more coordinate groups and forming a ring structure containing a metal atom is preferably used in terms of stability of the organic complex compound itself or stability of the heat sensitive layer composition solution.
20 [0031]
Preferable examples of major metals that form an organic complex compound include AI(III), Ti(IV), Mn(Il), Mn(lII), Fc(JI), Fe(lll), Co(II), Co(Ill), Ni(ll), Ni(lV), Cu(I), Cu(ll), Zn(II), Ge, In, Sn(IJ), Sn(IV), Zr(lV), and Hf(IV). Al(lII) is particularly preferable in thai it is effective for the improvement of
25 sensitivity, and Ti(lV) is particularly preferable in that it tends lo express resistance to a printing ink or ink washing agent. [0032]

12
Examples of the ligand are compounds having coordinate groups having oxygen, nitrogen, sulfur, and the like as a donor atom. Specific examples of the coordinate group include: as coordinate groups having oxygen as a donor atom, -OH (alcohol, enol and phenol), -COOH (carboxylic acid), >C=0 (aldehyde, ketone, quinine), -O- (ether), -COOR (ester; R represents aliphatic or aromatic hydrocarbon), -N^O (nitroso compounds), -N02 (nitro compounds), >N-0 (N-oxide), -SO3H (sulfonic acid), -PO3H2 (phosphorous acid), etc.; as coordinate groups having nitrogen as a donor atom, -NII2 (primary amine, hydrazine), >NH (secondary amine, hydrazine), >N- (tertiary amine), -N=N- (azo compounds, heterocyclic compounds), =N-OH (oxime), -NO2 (nitro compounds), -N=0 (nitroso compounds), >C=N-(Schiff base, heterocyclic compounds), >C=NH (aldehyde, ketonimine, enamines), -NCS (isothiocyanato), etc.; and, as coordinate groups having sulfur as a donor atom, -SH (thiol), -S- (thioether), >C=S (thioketone, thioamide), =S- (heterocyclic compounds), -C(=0)-SH, -C(=S)-OH and -C(=S)-SH (thiocarboxylic acid), -SCN (thiocynate), etc. [0033]
Among the above organic complex compounds formed with metals and coordinate groups, examples of organic complex compounds that are preferably used include complex compounds of metals AI(IIl), Ti(IV), Fe(II), Fe(JII), Mn(III), Co(Ji), Coilll), Ni(Ii), Ni(IV), Cu(l), Cu(ll), Zn(II), Ge, In, Sn(II), Sn(iV), Zr(IV), and Hf(IV)with (3-diketones, amines, alcohols, and carboxylic acids. Examples of further preferable complex compounds include acetylacctone complexes and acetoacetic acid ester complexes of Al(III), Fc(II), Fe(IH), Ti(IV), and Zr(IV). [0034]
As specific examples of such compounds, it is possible to cite the following compounds: aluminium iris-(acetylacctonate), aluminium tris-(ethylacetoacetate), aluminium tris(propylacetoacctatc), aluminium tris(butylacetoacetate), aluminium

13
tris(hexyi-acetoacetate), aluminium Iris(nonylacetoacetate), aluminium
tris-(hexafluoropentadionale), aluminium
tris~(2,2,6,6-tetramethyl-3,5-heptancdionate); aluminium
bis(ethyIacetoacetate)mono(acetylacetonate), aluminium 5 bis(acetylacetonate)mono(ethylacetoacetate), aluminium
bis(propylacetoacetate)mono(acetylacetonate), aluminium
bis(butylacetoacetate)mono(acetylacetonate), aluminium
bis(hexyl-acetoacetate)mono(acetylacetonate), aluminium
bis(propylacetoacelate)mono(ethyIacetoacetate), aluminium 10 bis(butylaceloacetate)mono(ethyiacetoacetate), aluminium
bis(hexyl-acetoacetate)mono(ethylacetoacetate). aluminium
bis(nonylacetoacetate)mono(ethylacetoacetate), aluminium dibutoxide mono(acelylacetonate), aluminium diiso-propoxide mono(acetyiacetonate), aluminium diiso-propoxide mono(ethylacetoacetate), aluminium-s-butoxide 15 bis(elhylacetoacetate), aluminium di-s-butoxide mono(ethylacetoacetate), aluminium diiso-propoxide mono(-9-octadecenylacetoaeetate)5 titanium triiso-propoxide mono(allyiacetoacetate), titanium diiso-propoxide bis(trielhanolamine), titanium di-n-butoxide bis(triethanolamine), titanium diiso-propoxide bis(acetylacetonatc), titanium di-n-butoxide bis(acetylacetonate), titanium diiso-propoxide 20 bis(2,2,6,6-(tetramethyi-3,5-heplane-dionate), titanium diiso-propoxide
bis(ethylacetoacetate), titanium di-n-butoxide bis(ethylacetoacetate), titanium tri-n-buloxide mono(ethylacetoaeetate), titanium triiso-propoxide mono(methacryloxyethylacetoacetate), titanium oxide bis(acetylacetonate), titanium tetra(2-ethyl-3-hydroxyhexyloxidc), titanium dihydroxy bis(lactate), 25 titanium(ethylenc glycolate)bis(dioctyI phosphate), zirconium di-n-butoxide bis(acetylacetonate), zirconium tetrakis(hexafluoropentanedionate), zirconium tclrakis(trifluoropentanedionate), zirconium tri-n-propoxide

14
mono(methacryloxyethylacetoacetate), zirconium tetrakis(acetylacetonate), zirconium tetrakis(2,2,6,6-tetramethyi-3,5-heptanedionate), triglycolate zirconate, trilactate zirconate, iron (III) acetylacetonate, dibenzoylmethane iron (II), tropolone iron, tristropolono-iron (III), hinokitiol iron, trishinokitiolo-iron (III), acetoacetic 5 acid ester iron (III), iron( III) benzoylacetonate, iron (111) diphenylepropanedionate, ion (III) tetramethylheptanedionate, and iron (III) trifluoropentanedionate. Of these, two or more compounds may be contained. [0035]
Such organic complex compound functions as a crosslinker for polymers.
10 The amount thereof is preferably 0.5% by mass or more in the heat sensitive layer. From the point of view of the printing durability of the printing plate, it is preferably 50% by mass or less. [0036]
In addition, when a novolak resin is used as a polymer contained in the
15 composition of the heat sensitive layer, the mass ratio of novolak resin : organic
complex compound is preferably 2 or more, more preferably 2.5 or more, and further preferably 3 or more in order to achieve highly fine image reproducibility. In addition, the mass ratio of novolak resin : organic complex compound is preferably 6 or less, more preferably 5.5 or less, and further preferably 5 or less so that a
20 crosslinked structure of a novolak resin is densely formed, thereby increasing
hardness of the heal sensitive layer. By setting the mass ratio of novolak resin : organic complex compound within the above range, it is possible to further increase hardness of the heat sensitive layer, thereby allowing the ink repellent layer to be deformed when an ink roller applies pressure on the ink repellent layer which is an
25 upper layer during printing. As a result, an ink repellent liquid is likely to come out on the surface of the ink repellent layer, thereby improving ink repellency. [0037]

15
According to the present invention, a light-to-heat converting substance that can be contained in the compositions (A) and (B) of the heat sensitive layer is preferably a light-lo-heat converting substance that functions to absorb the laser beam, convert the light energy into atomic/molecular motion energy, and instantly 5 generate heat at 200°C or more on the surface of the heat sensitive layer, thereby
degrading the crosslinked structure of the heal sensitive layer by heat. In particular, infrared- or near infrared-absorbing pigments and dyes are preferable. Examples thereof include: black pigments such as carbon black, carbon graphite, aniline black, and cyanine black; green pigments of phthalocyanine and naphthalocyanine; crystal
10 water-containing inorganic compounds; metal powders of iron, copper, chromium, bismuth, magnesium, aluminium, titanium, zirconium, cobalt, vanadium, manganese, and tungsten; sulfides, hydroxydes, silicates, hydrosulfates, phosphates, diamine compounds/complexes, dilhiol compounds/complexes, phenolthiol compounds/complexes, and mercaptophenol compounds/complexes of these metals.
15 [0038]
In addition, as infrared- or near infrared-absorbing dyes, cyanine dyes, azulenium dyes, squarilium dyes, croconium dyes, azo disperse dyes, bisazostilbene dyes, naphthoquinone dyes, anthraquinone dyes, peryiene dyes, phthalocyanine dyes, naphthalocyanine metal compiex dyes, polymcthine type dyes, dithiolnickel complex
20 dyes, indoaniiine metal compiex dyes, intermoiecuiarCTdyes, benzothiopyran (ype spiropyran and nigrosine dyes, which are dyes employed for electronics or for recording, and have a maximum absorption wavelength in the range from 700 nm to 1500 nm, arc preferably used. [0039]
25 Amongst these dyes, those having a large molar absorptivity £ are preferably
used. Specifically, e is preferably at least I x 10 L^mofcm) and more preferably at least 1x10' L/(molcm). When r, is 1 xl04L/(mol*cm) or more, initial sensitivity

16
can be further improved. Here, the coefficient is based on active energy ray for irradiation. Specific wavelengths may be 780 nm, 830 nm, or 1064 nm. [0040]
Two or more light-to-heat converting substances may be contained. By 5 allowing the ink repellent layer to contain two or more light-to-heat converting substances with different absorption wave-lengths, it is also possible to utilize with two or more types of laser with different emission wavelengths. [0041J
Among them, carbon black and infrared- or near infrared-absorbing dyes are 10 preferable in view of light-to-heat conversion rate, economy and handling ease. [0042]
The content of these light-to-heat converting substances is preferably from 0.1 to 70% by mass, and more preferably from 0.5 to 40% by mass in the heat sensitive layer. By setting the light-to-heat converting substance content to 0.1% by 15 mass or more, it is possible to further improve sensitivity to laser beam. Meanwhile, when the content is set to 70% by mass or less, high printing durability of the printing plate can be maintained. [0043]
In addition, the heat sensitive layer of the waterless lithographic printing 20 plale precursor of the present invention may various additives, if necessary. For instance, the heat sensitive layer may contain a silicone-based surfactant or a fiuorochemical surfactant in order to improve application performance. In addition, in order to enhance the adhesion between the heat sensitive layer and the ink repellent layer, the heat sensitive layer may contain a silane coupling agent, a 25 titanium coupling agent, or the like. The contents of these additives may differ
depending on intended use; however, it is usually 0.1% by mass to 30% by mass with respect to the total solid content of the heat sensitive layer.

17
[0044]
A silicone rubber layer, which is crosslinked organopolysiloxane, can be preferably used for the ink repellent layer of the waterless lithographic printing plate precursor of the present invention. In particular, the silicone rubber layer is, a layer 5 obtained by applying an addition reaction-type silicone rubber layer composition or a condensation reaction-type silicone rubber layer composition, a layer obtained by applying and drying a solution of such composition, or the like. [0045]
It is preferable for the addition reaction-type silicone rubber layer 10 composition to contain at least vinyl group-containing organopolysiloxane, an SiH group-containing compound having a plurality of hydrosilyl groups (hereafter referred to as "addition reaction-type crosslinker), and a curing catalyst. Further, addition reaction-type silicone rubber layer composition may contain a reaction inhibitor. 15 [0046]
The vinyl group-containing organopolysiloxane has a structure represented by the following general formula (I), and has a vinyl group at the main-chain end or within the main chain. Among these, vinyl group-containing organopolysiloxanes having a vinyl group at the main-chain end are particularly preferable. Of these, 20 two or more compounds may be contained. -(SiR'R2-0-)13- (I) In formula (I), n is an integer of not less than 2. R and R" each represent a saturated or unsaturated hydrocarbon group with 1 to 50 carbon atoms. A hydrocarbon group may have a linear-chain, branched, or cyclic structure, or may 25 have an aromatic ring. R and R" may be the same or different. A plurality of R present in polysiloxane of general formula (1) may be the same or different. In addition, a plurality of R" present in polysiloxane of general formula (I) may be the

18
1 0
same or different. It is preferable for R and R" in the general formula (1) to have methyl groups that account for at least 50% of R1 and R2 as a whole, in view of ink repellency of the printing plate. The weight average molecular weight of vinyl group-containing organopolysiioxane is preferably 10,000 to 600,000 in view of 5 handling ease and ink repellency or scratch resistance of the printing plate. [0047]
Examples of the SiH group-containing compound include organohydrogen polysiloxane and organic polymers having a diorganohydrogensilyl group. Organohydrogen polysiloxane is preferable. Of these, two or more compounds may
10 be contained. [0048]
Organohydrogen polysiloxane may have a linear-chain, cyclic, branched, or web molecular structure. Examples thereof include the following: polymethylhydrogensiloxanes sealed with trimethylsiloxy groups at the molecular
15 chain ends, dimethylsiloxane/methylhydrogensiloxane copolymers sealed with trimethylsiloxy groups at the molecular chain ends,
dimethylsiloxane/methylhydrogensiloxane/methylphenylsiloxane copolymers sealed with trimethylsiloxy groups at the molecular chain ends, dimethylpolysiloxanes sealed with dimethylhydrogensiloxy groups at the molecular chain ends,
20 dimethylsiloxane/mcthylphenylsiloxane copolymers sealed with dimethylhydrogensiloxy groups at the molecular chain ends, and methylphenylpolysiloxanes sealed with dimethylhydrogensiloxy groups at the molecular chain ends; and an organopolysiioxane copolymer comprising a siioxane unit represented by R3SiO]/2, a siioxane unit represented by R2HSiO]/2, and a
25 siioxane unit represented by Si04/2; an organopolysiioxane copolymer comprising a siioxane unit represented by R2HSiOi/2 and a siioxane unit represenled by SiO^; an organopolysiioxane copolymer comprising a siioxane unit represented by RHSiO?^,

19
a siloxane unit represented by RSI03/2, and a siloxane unit represented by HSiCh/i. [0049]
Two or more examples of organopolysiloxane described above may be used. In the above formulae, R independently represents a monovalent hydrocarbon other 5 than an alkenyl group, which may be substituted. Examples thereof include: alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyi group, a hexyl group, and a heptyl group; aryl groups such as a phenyl group, a tolyl group, a xylyi group, and a naphtyl group; aralkyl groups such as a benzil group and a phenetyl group; alkyl halide groups such as a chloromelhyl group,
10 3-chloropropyl group, and 3,3,3-trifluoropropyl group. [0050]
Examples of organic polymers having a diorganohydrogensilyl group include the following: oligomers formed via polymerization of: dimethylhydrogensilyl group-containing (meth)acrylic monomers of
15 dimethylhydrogensilyl(meth)acryIate, dimethylhydrogensily!propyl(meth)acrylate, etc.; and monomers of methyl(meth)acryiate, ethyl(meth)acrylatc, butyl(meth)acryiate, ethylhexyl(meth)acrylate, !auryl(meth)aerylate, styrene, a-methylstyrene, maieic acid, vinyl acetate, allyl acetate, etc. [0051]
20 The content of the SiH group-containing compound is preferably 0.5% by
mass or more and more preferably 1% by mass or more in the silicone rubber layer composition in view of hardenability required for silicone rubber layer formation. In addition, in terms of the ease of controlling the curing rate, the content is preferably 20% by mass or less and more preferably 15% by mass or less.
25 [0052]
Examples of the reaction inhibitor include nitrogen-containing compounds, phosphorus-based compounds, unsaturated alcohols, etc. Acetylene

20
group-containing alcohols are preferably used. Of these, two or more compounds may be contained. It is possible to adjust the rale of curing of the silicone rubber layer by adding such reaction inhibitors. The content of the reaction inhibitor is preferably 0.01% by mass or more and more preferably 0.1% by mass or more in the 5 silicone rubber layer composition in view of stability of the silicone rubber layer composition or a solution thereof. In addition, the content is preferably 20% by mass or less and more preferably 15% by mass or less in the silicone rubber layer composition in view of hardenability of the silicone rubber layer. [0053]
10 A curing catalyst can be selected from among known curing catalysts.
Platinum-based compounds are preferable. Specific examples include platinum, platinum chloride, chloroplatinic acid, olefin coordinated platinum, alcohol modified complex of platinum, and methylvinyl polysiloxane complex of platinum. Two or more platinum-based compounds may be contained. The content of the curing
15 catalyst is preferably 0.001% by mass or more and more preferably 0.01% by mass or more in the silicone rubber layer composition in view of hardenability of the silicone rubber layer. In addition, the content is preferably 20% by mass or less and more preferably 15% by mass or less in the silicone rubber layer composition in view of stability of the silicone rubber layer composition or a solution thereof.
20 [0054]
In addition to the aforementioned compounds, the ink repellent layer may also contain a hydroxy! group-containing organopolysiloxane or hydrolyzable functional group-containing siiane or the functional group-containing siloxane, and a known filler such as silica or the like for improving the rubber strength, and a known
25 siiane coupling agent for improving the adhesion. Preferable siiane coupiing agents include alkoxysilanes, aceloxysilanes, and kctoximinosilanes. Particularly, a coupiing agent having a vinyl group or an ally) group which is directly bound to a

21
silicon atom is preferable. [0055]
It is preferable for the condensation reaction-type silicone rubber layer composition to contain, as materials, at least hydroxyl group-containing 5 organopolysiloxane, a crosslinker, and a curing catalyst. [0056]
The hydroxyl group-containing organopolysiloxane has a structure represented by the general formula (I), and have a hydroxyl group at the main-chain end and/or in the main chain. A hydroxyl group-containing organopolysiloxane, 10 which has a hydroxyl group at the main-chain end, is particularly preferable. Of these, two or more compounds may be contained. [0057]
Examples of the crosslinker contained in the condensation reaction-type silicone rubber layer composition include, for example, de-acetic-acid type, 15 de-oxime type, de-alcohol type, de-acetone type, de-amide type, and
de-hydroxylamine type silicon compounds represented by the following formula (II). (R3)4.mSiXm (II)
In (he formula, m represents an integer of 2 to 4; R" may be the same or different and represents a substituted or non-substituted alkyl group with 1 or more 20 carbon atoms, alkenyl group, aryl group, or a group formed by combining the foregoing groups). X may be the same or a different hydrolyzable group. Examples of hydrolyzable groups include: acyioxy groups such as an acetoxy group; ketoxime groups such as a mcthylcthylketoxime group; alkoxy groups such as a methoxy group, an cthoxy group, a propoxy group, and a butoxy group; alkenyloxy 25 groups such as an isopropenoxy group; acylalkylamino groups such as an
acetylethylamino group; and aminooxy groups such as a dimethyiaminooxy group. In the foregoing formula, it is preferable that the number m of the hydrolyzable

22
groups is 3 or 4.
[0058]
Specific compounds include the following compounds:
acetoxysilanes such as methyltriacetoxysilane, ethyltriacetoxysilane, 5 vinyltriacetoxysilane, allyltriacetoxysilane, phenyltriacetoxysilane, and
tctraacetoxysilane; ketomiximinosilanes such as
vinylmelhylbis(methylethylketoximino)silane,
methyltris(methylethylketomiximino)silane,
ethyItris(methylethylketomiximino)silane, vinyll'ris(methylethylketoximino)silane, 10 aIlyltris(methylethylketomiximino)silane,
phenyltris(methylethylketomiximino)silane, and
tetrakis(methyiethylketomiximino)silane; alkoxysilanes such as
methyitrimethoxysilane, methyltriethoxysiiane, ethyltrimethoxysilane,
ethyltriethoxysilane, tetraethoxysilane, tetrapropoxysilane, vinyltrimethoxysiiane, 15 vinyltrielhoxysilane, aliyltriethoxysilane, and vinyltriisopropoxysilane;
alkenyloxysilanes such as vinyitrisisopropenoxysilane,
diisopropenoxydimethylsilane, and triisopropenoxymethylsilane; and
tetraaliyloxysilane.
[0059]
20 Among these compounds, acetoxysilanes or ketoximinosilanes are
preferable in view of the curing rate of the silicone rubber layer, handling ease, etc.
Of these, two or more compounds may be contained.
[0060]
When the above crosslinker is mixed with hydroxyl group-containing 25 organopolysiloxane, the crosslinker reacts with a silanoi group. As a resull, the
silanoi group is replaced by the crosslinker, which may results in organopolysiloxane
to which the crosslinker is bound. Therefore, in some cases, the silicone rubber

2
composition contains organopolysiloxane to which ihe crosslinker is bound but not
organopolysiloxane containing a silanol group.
[0061]
The amount of the crosslinker added to the condensation reaction-type 5 silicone rubber layer composition is preferably 0.5% by mass or more and more preferably 1% by mass or more in view of stability of the silicone rubber layer composition or a solution thereof. In addition, the amount is preferably 20% by mass or less and more preferably 15% by mass or less in the silicone rubber layer composition in view of strength of the silicone rubber layer or scratch resistance of
10 the printing plate. [0062]
Examples of the curing catalyst contained in the condensation reaction-type silicone rubber layer composition include organic carboxylic acids, acids, alkali, amine, metal alkoxide, metal diketonate, and organic metal salts of tin, lead, zinc,
15 iron, cobalt, calcium, and manganese. Specific examples thereof include dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, zinc octylate, and iron octylate. Of these, two or more compounds may be contained. [0063]
The content of the curing catalyst in the condensation reaction-type silicone
20 rubber layer composition is preferably 0.001% by mass or more and more preferably 0.01% by mass or more in the silicone rubber layer composition in view of hardenability and adhesion of the silicone rubber layer. In addition, the content is preferably 15% by mass or less and more preferably 10% by mass or less in the silicone rubber layer composition in view of stability of the silicone rubber layer
25 composition or a solution thereof. [0064]
The ink repellent layer of the waterless lithographic printing plate precursor

24
of the present invention contains an ink repellent liquid for the purpose of improving ink repellency. The boiling point of this liquid at 1 atmospheric pressure is preferably 150°C or more. When the plate surface is pressurized during printing, the ink repellent liquid comes out to the surface of the ink repellent layer, which 5 facilitates ink to fall off. Thus, ink repellency is improved. When the boiling point is 150°C or more, the ink repellent layer is unlikely to volatilize during the production of the waterless lithographic printing plate precursor so that the ink repelling effects obtained with the addition of this liquid will not be lost. The boiling point mentioned herein is defined as a temperature at which a decrease in
10 mass after static placement for 1 hour in an environment at 1 atmospheric pressure is 0.5% by mass or more. In other words, the liquid has a decrease in mass after static placement for 1 hour in an environment at 150°C and 1 atmospheric pressure, which is less than 0.5% by mass. If this is the case, the ink repelling effects obtained with the addition of this liquid will not be lost.
15 [0065]
In addition, the surface tension at 25°C of the ink repellent liquid is preferably 15 mN/m to 30 mN/m. If the surface tension is 15 mN/m or more, affinity with other ink repellent layer components is improved, thereby increasing stability of the solution of the ink repellent layer composition. If the surface tension
20 is 30 mN/m or less, ink becomes prone to fall off, thereby further improving ink repellency. [0066]
The content of the ink repellent liquid in the ink repellent layer is preferably 10% by mass or more so that the ink repellent liquid is allowed to sufficiently come
25 out lo the surface of the ink repellent layer, thereby remarkably improving ink
repellency. In addition, in order to maintain the film strength of the ink repellent layer, the content of the ink repellent liquid is preferably 30% by mass or less and

25
more preferably 25% by mass or less. [0067]
The ink repellent liquid contains preferably a silicone material and more preferably silicone oil. The term "silicone oil" used herein refers to a free 5 polysiloxane component which is not involved in crosslinkage in the ink repellent layer. Accordingly, examples thereof include: dimethyl silicone oils of terminal-dimethyl polydimethylsiloxane, cyclic polydimethylsiloxane, terminal-diinethyl-polydimcthyl-polymethilphenylsiloxane copolymer, and terminal-dimethyl-polydimethyl-polydiphenylsiloxane copolymer; or denatured
10 silicone oils, in which various organic groups are introduced into a part of an
intramolecular methyl group, such as alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, amino-inodified silicone oil, epoxy-modified silicone oil, epoxypolyether-modified silicone oil, phenol-modified silicone oil, carboxy-modified silicone oil,
15 mercapto-modified silicone oil, amide-modified silicone oil, carnauba-modified silicone oil, higher fatty acid-modified silicone oil. [0068]
The molecular weights of these silicone oils can be determined by gel permeation chromatography (GPC) with the use of polystyrene as an authentic
20 preparation. Silicone oils having a weight average molecular weight Mw of 1,000 to 100,000 are preferable. [0069]
The plate surface elastic modulus of the waterless lithographic printing plate precursor of the present invention is preferably 4 MPa to 12 MPa. The plate surface
25 elastic modulus is obtained by pushing a conical diamond indenter into the surface of the ink repellent layer of the printing plate precursor by nanoindentation, and creating a load-indentation depth diagram, thereby calculating the elastic modulus

26
with respect to a load. The plate surface elastic modulus is defined as an elastic modulus when a load of 1400N/ITT is applied to the surface of the printing plate precursor. Details of the determination method will be described in the Examples below. 5 [0070]
The plate surface elastic modulus is preferably 4 MPa or more, more preferably 5 MPa or more, and further preferably 7 MPa or more so that the film strength of the ink repellent layer is improved and plate wear is increased. In addition, the plate surface elastic modulus is preferably 12 MPa or less so as to
10 improve leaching of the ink repellent liquid into the surface of the ink repellent layer, re-incorporation of the ink repellent liquid into the ink repellent layer, or incorporation of the liquid components in ink into the surface of the ink repellent layer, thereby maintaining ink repellency. The plate surface elastic modulus is further preferably 11 MPa or less and yet further preferably 10 MPa or less, in
15 particular, when the plate surface elastic modulus is set to 10 MPa or less, ink repellency is remarkably improved. [0071]
The waterless lithographic printing plate precursor of the present invention may have a protective film and/or interleaving paper on the surface of the ink
20 repellent layer for the purpose of protecting the ink repellent layer. [0072]
As the protective film, a film having a thickness of 100 urn or less at which light with a wavelength of an exposure light source sufficiently permeates the film. Typical examples of materials for the protective film include polyethylene,
25 polypropylene, polyvinyl chloride, polyethylene terephthalate, and cellophane. In addition, various light-absorbing agents, photochromic substances, and photobleaching substances disclosed in Japanese Patent No. 2938886 may be present

27
on the protective film for the purpose of preventing sensitization of the plate
precursor due to light exposure
[0073]
As the interleaving paper, an interleaving paper having a weight per square meter of 30 to 120 g/m" is preferable, and an interleaving paper having a weight per square meter of 30 to 90 g/m" is more preferable. When the weight per square meter is 30 g/nr or more, sufficient mechanical strength is achieved. When it is 120 g/m" or less, it is economically advantageous, and it is also advantageous in terms of workability because a layered product of the waterless lithographic printing plate precursor and a paper can be thinned. Examples of interleaving paper that can be preferably used include, but are not limited to, printing media (40 g/m"; Nagoya Pulp Corporation), metal interleaving paper (30 g/m ; Nagoya Pulp Corporation), unbleached kraft paper (50 g/m"; Chuetsu Pulp & Paper Co., Ltd.), NIP paper (52 g/m2 Chuetsu Pulp & Paper Co., Ltd.) pure white rolled paper (45 g/m2; Oji Paper Co., Ltd.), Clupack paper (73 g/m ; Oji Paper Co., Ltd.). [0074]
. A method of producing a waterless lithographic printing plate from the waterless lithographic printing plate precursor of the invention will be described below. The method for producing a waterless lithographic printing plate includes a step of exposing the waterless lithographic printing plate precursor in accordance with an image (light exposure step) and a step of applying physical stimulations to the exposed lithographic printing plate precursor to remove the ink repellent layer in exposed regions (development step). [0075]
Firstly, the exposure step will be described. The waterless lithographic printing plate precursor is exposed to light in accordance with an image. When the waterless lithographic printing plate precursor has a protective film, light exposure

28
may be conducted on the protective film or after removal of the protective film. The laser beam sources used in the exposure step are laser beam sources whose emission wavelength region is within the range of 300 nm to 1500 mil. Among them, semiconductor lasers and YAG lasers whose emission wavelength regions are 5 adjacent to the near-infrared region are preferably used as the regions are widely used as regions having the absorption wavelength of the heat sensitive layer. Specifically, laser beam having a wavelength of 780 nm, 830 nm, and 1064 nm is preferably used in view of the light-to-heat conversion efficiency. [0076]
10 Secondly, the development step will be described. Physical stimulations
are applied to the exposed lithographic printing plate precursor to remove the ink repellent layer in exposed regions. Examples of a method for applying physical stimulations include: (i) a method wherein the plate surface is wiped off with nonwoven fabric, absorbent cotton, cloth, sponge, or the like impregnated with a
15 developer; (ii) a method wherein the plate surface is pretrealed with a developer and then rubbed with a rotary brush during showering with tap water; and (iii) a method wherein high-pressure water, warm water, or steam is injected to the plate surface. [0077]
Prior to development, prelrealment may be conducted in a manner such that
20 the plate is immersed in a prelrealment liquid for a certain period of time. As the pre-trealment liquid, it is possible to use, for example, water, a liquid obtained by adding a polar solvent, such as an alcohol, a ketone, an ester, or a carboxylic acid into water, or a liquid obtained by adding a polar solvent into a solvent made up of at least one selected from aliphatic hydrocarbons, aromalic hydrocarbons, etc., or use a
25 polar solvent. Furthermore, a known surfactant may be to the above developer composition. A preferable surfactant has pH of 5-8 in the form of an aqueous solution in terms of safety, disposal cost, etc. The content of the surfactant is

29
preferably 10% by mass or less with respect to (he amount of the developer. Such developer is highly safe and economically preferable in terms of disposal cost, etc. It is preferable that a glycol compound or a glycol ether compound be used as a major component. It is more preferable that an amine compound coexist. 5 [0078]
As the developer, for example, water, alcohol, or a paraffin type hydrocarbon compound can be used. In addition, a mixture of a propylene glycol derivative such as propylene glycol, dipropyiene glycol, triethylene glycol, polypropylene glycol, or alkylene oxide-added polypropylene glycol and water also
10 can be used. Specific examples of the developer include HP-7N and WH-3 (Toray Industries, Inc.) An example of the pre-treatment liquid that can be used is a pre-treatment liquid containing polyethylene ether diol and two or more primary amino groups disclosed in Japanese Patent No. 4839987. Specific examples of the pre-treatment liquid include PP-1, PP-3, PP-F, PP-FII, PTS-1, CP-1, CP-Y, NP-1, and
15 DP-1 (each produced by Toray Industries, Inc.). In addition, in order to increase visibility of imaging areas and measurement precision of halftone dots, it is also possible to add dyes such as Crystal Violet, Victoria Pure Blue, Astrazon Red, or the like to the pre-treatment liquid or developer so as to dye an ink accepting layer in each imaging area upon development. Further, il is also possible to perform dyeing
20 using a liquid, to which the above dye has been added, after development. [0079]
A part of or all of the above development step can be conducted automatically by an automatic processor. As an automatic processor, the following systems can be used: a system consisting of a development section, a system in
25 which a pre-treatment section and a development section are installed in that order, a system in which a pre-treatment section, a development section, and a post-treatment section are installed in that order, a system in which a pre-treatment section, a

30
development section, a post-treatment section, and a rinsing section are installed in that order, etc. Specific examples of such automatic processor include TWL-650 series, TWL-860 series, TWL-1160 series (each produced by Toray Industries, Inc.) and an automatic processor disclosed in Japanese Patent Application Laid-Open 5 Publication No. HEI5-6000, in which a stand has a curved recess in order to prevent scratching. These examples may be used in combination. [0080]
It is preferable to insert an interleaving paper between plates for the purpose of plate surface protection in order to prepare for a case in which developed
10 waterless lithographic printing plates are stacked for storage. [0081]
Next, a method of producing a printed material from the waterless lithographic printing plate of the invention will be described. A waterless lithographic printing plate is a lithographic printing plate which allows printing
15 without dampening water. A heat sensitive layer-derived layer forms an ink
accepting layer, which results in an imaging area. An ink repellent layer forms a non-imaging area. It can be said that the ink accepting layer and the ink repellent layer exist on the substantially same plane only with a micron-order difference in level. After inking is completed only in imaging areas by making use of a
20 difference in ink adhesiveness, an ink is transferred to a printing substrate for
printing. The term "printing substrate" refers to general printing media including thin paper, thick paper, 111m, label, and the like, which are not particularly limited. In addition, an ink may be transferred from a printing plate to a printing substrate directly or via a blanket.
25 [0082]
An ink curable with an active energy ray can be used for printing with the waterless lithographic printing plate of the invention. As long as such ink is an ink