JP6969304B2 - Ink film forming original plate, uneven pattern forming method, pattern film forming method, pattern film forming apparatus - Google Patents

Description

The present invention relates to an ink film forming original plate and a method for forming an uneven pattern thereof, and a pattern film forming method and a pattern film forming apparatus using the original plate.

In the case of conventional analog printing such as letterpress printing, intaglio printing, and lithographic printing, it is not easy to change the plate once the print pattern is formed, and it is necessary to create a new plate from the beginning every time a different printed matter is printed. Therefore, it takes time and cost to make a plate. In particular, in letterpress printing and intaglio printing, it is not easy to change the uneven shape once formed on the plate, and a long time loss and a high processing cost are required to produce the plate.

As a means of reducing this time loss and cost, digital plate making (that is, digital plate making) is also being promoted in the field of analog printing. Digital plate making is possible by applying computer to plate making technology (CTP technology), which is also known as digital image forming technology. For example, in Patent Document 1, in the case of letterpress printing using a photosensitive printing plate, the CTP technique is used as a means for obtaining a mask portion that covers a region of the photosensitive printing plate that should not be polymerized, which is necessary for forming irregularities on the plate. A technique for digital plate making has been proposed. However, since it is still necessary to make a new plate from the beginning every time a different printed matter is printed, even if digital plate making is performed, time loss and cost are incurred.

Therefore, in Patent Document 2, when the heated portion is rapidly cooled after heating, the heated portion expands thermally to form a convex portion, and when the convex portion is reheated and then slowly cooled, the convex portion shrinks and the convex portion disappears and returns to the original shape. It has been proposed that the properties of the storage resin can be applied to perform digital plate making and to enable plate rewriting. Specifically, by condensing and irradiating an intermediate recording medium (plate) having a shape memory resin layer on the surface with an energy beam, unevenness corresponding to the print pattern is formed (written), and the shape is stored after the ink is transferred. This is a method of eliminating unevenness by selectively heating the resin layer and then slowly cooling it.

Japanese Unexamined Patent Publication No. 2011-154251 Japanese Unexamined Patent Publication No. 7-256852

However, the method described in Patent Document 2 has a problem that the edge portion of a desired print pattern tends to be blurred and the reproducibility of small characters and fine images is poor.

Therefore, an object of the present invention is to provide an original plate for forming an ink film, which can be rewritten and has excellent fine line reproducibility.

As a result of diligent research, the present inventors have found that the above-mentioned problems can be solved by an ink film forming original plate which changes its shape in response to light energy and has a thermoplastic powder containing a thermoplastic resin on its surface. , The present invention has been completed.

The original plate for forming an ink film according to the present invention can be rewritten and has excellent fine line reproducibility.

It is a schematic sectional drawing which shows the pattern film forming apparatus which concerns on one Embodiment of this invention. It is a schematic diagram of the image pattern used for the plate rewriting evaluation of an Example.

A preferred embodiment of the present invention is an ink film forming original plate which changes its shape in response to light energy and has a thermoplastic powder containing a thermoplastic resin on its surface. The original plate for forming an ink film having this structure can be rewritten and has excellent fine line reproducibility. The original plate for forming an ink film of the present invention is also hereinafter referred to as a "printing original plate" or an "original plate".

As described above, the printing method disclosed in Patent Document 2 has a problem that the edge portion of a desired printing pattern tends to be blurred and the reproducibility of small characters and fine images is poor. The present inventors have speculated that the cause of the change is the "layer" of the shape memory resin and the change in shape due to the thermal response.

Therefore, as a result of diligent studies on the design of the original plate, the present inventors have made the original plate in which the shape changes in response to light energy and the thermoplastic powder containing the thermoplastic resin is arranged on the surface. I found that the problem could be solved.

The reason why the above effect is obtained by the original version of the present invention is unknown, but the following mechanism can be considered. The following mechanism is speculative, and the present invention is not limited to the following mechanism.

When the original plate having the thermoplastic powder containing the thermoplastic resin on the surface is pressed, the thermoplastic powder is deformed by receiving stress. On the other hand, when light is irradiated, the thermoplastic powder irradiated with light is elastically restored by the energy of light and returns from the deformed state to the original state. Therefore, the thermoplastic powder is in a convex state with respect to the thermoplastic powder that has not been irradiated with light. Therefore, only the portion irradiated with light according to the image information has a convex shape, and a desired uneven pattern can be formed on the surface of the original plate. Here, since the individual powders exist separately, the influence of the elastic recovery of the powder irradiated with light is less likely to reach the powders in the vicinity. Therefore, the powder existing in the vicinity of the light-irradiated powder remains deformed, and the concave state is maintained. Therefore, even when the image information is fine, the edge portion can form a clear uneven pattern. By applying ink to the concave or convex portions of this uneven pattern, an ink film is formed on the original plate. By transferring the ink film to the object to be printed, small characters and fine images can be clearly formed on the object to be printed. That is, it is excellent in fine line reproducibility. Further, by pressurizing the surface of the original plate after the ink film transfer again, the thermoplastic powder having a convex shape returns to the shape before elastic recovery by receiving stress. As a result, the surface of the original plate becomes smooth again, so that different uneven patterns can be formed (written) on the original plate. That is, the version can be rewritten.

As used herein, "(meth) acrylic" refers to methacryl and / or acrylic. Similarly, "(meth) acrylate" refers to methacrylate and / or acrylate.

In the present specification, "X to Y" indicating a range means "X or more and Y or less". Further, in the present specification, unless otherwise specified, the operation and the measurement of physical properties are performed under the conditions of room temperature (20 to 25 ° C.) / relative humidity of 40 to 50% RH.

<Original plate for forming ink film>
The original plate for forming an ink film according to the present invention has a thermoplastic powder whose shape changes in response to light energy and contains a thermoplastic resin on its surface.

[Structure of thermoplastic powder]
(Thermoplastic resin)
Examples of the thermoplastic resin contained in the thermoplastic powder include vinyl resins such as styrene resin, (meth) acrylic resin, styrene acrylic resin, and olefin resin; polyester resin, silicone resin, polyamide resin, and polycarbonate. Various known resins such as resins, polyethers, polyvinyl acetate resins, polysulfone resins, and polyurethane resins can be mentioned. These can be used alone or in combination of two or more. Further, a resin in which two or more kinds of resin segments are bonded to each other and composited may be used.

When a copolymerized thermoplastic resin such as a styrene acrylic resin is used as the thermoplastic resin, elastic recovery of the thermoplastic powder is more likely to occur, and the efficiency of forming an uneven pattern can be increased, which is preferable.

The glass transition point (Tg) of the thermoplastic resin is preferably 35 to 70 ° C. from the viewpoint of the rate of shape change and shape stability, and 40 to 65 ° C. from the viewpoint of further improving the effect of the present invention. It is more preferable that the temperature is 45 to 60 ° C., and it is even more preferable that the temperature is 45 to 60 ° C. Tg can be measured by differential scanning calorimetry (DSC).

The thermoplastic resin preferably contains at least one selected from the group consisting of styrene acrylic resin, polyester resin and polyurethane resin, and even more preferably contains styrene acrylic resin. When such a resin is contained, the uneven pattern can be formed more precisely, and small characters and fine images can be reproduced more clearly. In addition, the effect can be sustained even after the plate is repeatedly rewritten.

Hereinafter, a styrene acrylic resin and a polyester resin suitable as the thermoplastic resin will be described.

≪Styrene acrylic resin≫
The styrene acrylic resin is formed by polymerizing at least a styrene monomer and a (meth) acrylic acid ester monomer. Here, the styrene monomer includes not only styrene _{represented by the structural formula of CH 2} = CH-C ₆ H ₅ but also a structure having a known side chain or functional group in the styrene structure.

Further, the (meth) acrylic acid ester monomer has a functional group having an ester bond in the side chain. _{Specifically,} CH 2 = CHCOOR (R is an alkyl group) other acrylic acid ester monomer represented _by, methacrylic acid ester represented by _{CH 2 = C (CH 3)} COOR (R is an alkyl group) Contains vinyl ester compounds such as monomers.

Hereinafter, specific examples of the styrene monomer and the (meth) acrylic acid ester monomer capable of forming the styrene acrylic resin are shown, but the present invention is not limited to those shown below.

Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, and p-. Examples thereof include tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene and pn-dodecyl styrene.

The (meth) acrylic acid ester monomer is typified by the acrylic acid ester monomer and the methacrylic acid ester monomer shown below, and the acrylic acid ester monomer is, for example, methyl acrylate. , Ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate , Phenyl acrylate and the like. Examples of the methacrylic acid ester monomer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, and n-octyl methacrylate. , 2-Ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate and the like.

These styrene monomer, acrylic acid ester monomer, or methacrylic acid ester monomer can be used alone or in combination of two or more.

Further, in the styrene acrylic resin, in addition to the above-mentioned copolymer formed only of the styrene monomer and the (meth) acrylic acid ester monomer, these styrene monomers and the (meth) acrylic acid ester single amount In addition to the body, some are formed in combination with general vinyl monomers. Hereinafter, vinyl monomers that can be used in combination when forming the styrene acrylic resin referred to in the present invention will be exemplified, but the vinyl monomers that can be used in combination are not limited to those shown below.

(1) Olefins Ethylene, propylene, isobutylene, etc. (2) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc. (3) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc. (4) Vinyl ketones Vinyl methyl ketone, etc. Vinyl ethyl ketone, vinyl hexyl ketone, etc. (5) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc. (6) Other vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylonitrile, methacrylo Acrylic acids such as nitriles and acrylamides or methacrylic acid derivatives.

It is also possible to prepare a resin having a crosslinked structure by using a polyfunctional vinyl monomer. Furthermore, it is also possible to use a vinyl monomer having an ionic dissociation group in the side chain. Specific examples of the ionic dissociation group include a carboxyl group, a sulfonic acid group, a phosphoric acid group and the like. Specific examples of these vinyl monomers having an ionic dissociation group are shown below.

Specific examples of the vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, silicic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester and the like. ..

The method for forming the styrene acrylic resin is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. If necessary, known chain transfer agents such as n-octyl mercaptan and octyl 3-mercaptopropionate may be used.

When forming the styrene acrylic resin used for the thermoplastic powder, the contents of the styrene monomer and the (meth) acrylic acid ester monomer are not particularly limited, and the softening point temperature of the thermoplastic resin and the softening point temperature are not particularly limited. It can be appropriately adjusted from the viewpoint of controlling the glass transition temperature. Specifically, the content of the styrene monomer is preferably 40 to 95% by mass, more preferably 50 to 80% by mass, based on the whole monomer. The content of the (meth) acrylic acid ester monomer is preferably 5 to 60% by mass, more preferably 20 to 50% by mass, based on the total amount of the monomer.

The method for producing the styrene acrylic resin is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. Specific examples of the oil-soluble polymerization initiator include the following azo-based or diazo-based polymerization initiators and peroxide-based polymerization initiators.

Examples of the azo-based or diazo-based polymerization initiator include 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, and 1,1'-azobis (cyclohexane-1). -Carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like.

Examples of the peroxide-based polymerization initiator include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumenehydroperoxide, tert-butylhydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, 2, Examples thereof include 4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-tert-butylperoxycyclohexyl) propane, tris- (tert-butylperoxy) triazine and the like.

Further, when the styrene acrylic resin is produced by the emulsion polymerization method, it can be produced as described in (1) Preparation step of the thermoplastic resin particle dispersion liquid of [Method for producing a thermoplastic powder] described later.

The glass transition temperature (Tg) of the styrene acrylic resin is preferably in the range of 35 to 70 ° C, more preferably in the range of 40 to 60 ° C, from the viewpoint of fixability and heat-resistant storage. Tg can be measured by differential scanning calorimetry (DSC).

≪Polyester resin≫
The polyester resin is a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid component) and a divalent or higher alcohol (polyhydric alcohol component). The polyester resin may be amorphous or crystalline.

The valences of the polyvalent carboxylic acid component and the polyhydric alcohol component are preferably 2 to 3 respectively, and particularly preferably 2 each. Therefore, as a particularly preferable form, the valences are 2 each (that is, dicarboxylic acid). The acid component and the diol component) will be described.

Examples of the dicarboxylic acid component include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid, and 1,10-decandicarboxylic acid. (Dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanediocarboxylic acid, 1,18 -Saturated aliphatic dicarboxylic acids such as octadecanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids such as methylenesuccinic acid, fumaric acid, maleic acid, 3-hexendioic acid, 3-octendioic acid, dodecenylsuccinic acid; phthalic acid, Telephthalic acid, isophthalic acid, t-butylisophthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-phenylene diacetic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, anthracendicarboxylic acid, etc. , And the like, and these lower alkyl esters and acid anhydrides can also be used. The dicarboxylic acid component may be used alone or in combination of two or more.

In addition, trimellitic acid, polyvalent carboxylic acid having a valence of 3 or more such as pyromellitic acid, anhydrate of the above carboxylic acid compound, or an alkyl ester having 1 to 3 carbon atoms can also be used.

Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-heptane. Glycol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecane Saturated aliphatic diols such as diols, 1,18-octadecanediol, 1,20-eicosanediol, neopentyl glycol; 2-butene-1,4-diol, 3-butene-1,4-diol, 2-butin Unsaturated aliphatic diols such as -1,4-diol, 3-butin-1,4-diol, 9-octadecene-7,12-diol; bisphenols such as bisphenol A and bisphenol F, and their ethylene oxide addition. Aromatic diols such as alkylene oxide adducts of bisphenols such as propylene oxide adducts, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,2) ) -2,2-Bis (4-hydroxyphenyl) propane and the like can be mentioned, and derivatives thereof can also be used. The diol component may be used alone or in combination of two or more.

The method for producing the polyester resin is not particularly limited, and examples thereof include a method of polycondensing (esterifying) the polyvalent carboxylic acid component and the polyhydric alcohol component using a known esterification catalyst.

As catalysts that can be used in the production of polyester resins, alkali metal compounds such as sodium and lithium; compounds containing Group 2 elements such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin and zirconium, Examples include metal compounds such as germanium; subphosphate compounds; phosphate compounds; and amine compounds. Specifically, examples of the tin compound include dibutyltin oxide, tin octylate, tin dioctylate, and salts thereof. Titanium compounds include titanium alkoxides such as tetranormal butyl titanate (Ti (On-Bu) ₄ ), tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; titanium tetra. Examples thereof include titanium chelate such as acetylacetonate, titanium lactate, and titanium triethanol aminate. Examples of the germanium compound include germanium dioxide and the like. Further, examples of the aluminum compound include polyaluminum hydroxide, aluminum alkoxide, and tributylaluminate. These may be used alone or in combination of two or more.

The polymerization temperature is not particularly limited, but is preferably 70 to 250 ° C. Further, the polymerization time is not particularly limited, but is preferably 0.5 to 10 hours. During the polymerization, the pressure inside the reaction system may be reduced, if necessary.

The glass transition temperature (Tg) of the polyester resin is preferably in the range of 35 to 70 ° C, more preferably in the range of 40 to 60 ° C, from the viewpoint of fixability and heat-resistant storage. Tg can be measured by differential scanning calorimetry (DSC).

The lower limit of the content of the thermoplastic resin is 50% by mass or more, more preferably 65% by mass or more, still more preferably 75% by mass or more, particularly, with respect to the total mass of the thermoplastic powder. It is preferably more than 80% by mass. If it is equal to or more than the lower limit value (exceeding), the resin ratio becomes relatively large, so that the elastic recovery by light irradiation and the formation of the uneven pattern become more remarkable (upper limit value: 100% by mass). When the thermoplastic powder contains a compound that absorbs light, which will be described later, the upper limit of the content of the thermoplastic resin is preferably 99.9% by mass or less with respect to the total mass of the thermoplastic powder. , More preferably 99.5% by mass or less, still more preferably 98% by mass or less, and particularly preferably 95% by mass or less. When it is not more than the upper limit value, the effect of improving the elastic recovery rate of the powder by the compound that absorbs light is good.

(Compound that absorbs light)
The thermoplastic powder preferably further contains a compound that absorbs light (hereinafter, also referred to as a light absorbing compound). By containing the light absorbing compound, the efficiency of elastic recovery of the thermoplastic powder by light irradiation is improved. Therefore, a desired uneven pattern can be easily formed, and small characters and fine images can be clearly reproduced. In addition, the effect can be sustained even after the plate is repeatedly rewritten.

The light absorbing compound is dissolved in a solvent (DMF, THF, chloroform, etc.) at a concentration of 0.01% by mass, and when the absorbance is measured with a spectrophotometer, it has an arbitrary wavelength (for example, a wavelength of 180 to 900 nm). Refers to a compound having an absorbance of 0.01 or more (wavelength within the range of).

As the light absorbing compound, a compound capable of efficiently absorbing the light irradiated when forming the uneven pattern is preferable. Here, a suitable range of the maximum emission wavelength of the irradiated light is as described in [Writing means (step)] of <Pattern film forming apparatus and pattern film forming method> described later. Therefore, the upper limit of the maximum absorption wavelength of the light absorption compound is preferably 850 nm or less, and more preferably 550 nm or less. Further, the lower limit of the maximum absorption wavelength of the light absorption compound is preferably 280 nm or more. Therefore, in a preferred embodiment of the invention, the light absorbing compound has a maximum absorption wavelength in the wavelength range of 280-550 nm. When a light-absorbing compound having a maximum absorption wavelength in this wavelength range is used, the elastic recovery efficiency of the powder when irradiated with short-wavelength light is further improved, so that small characters and fine images can be reproduced more clearly. can.

The lower limit of the content of the light absorbing compound is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 2% by mass, based on the total mass of the thermoplastic powder. % Or more, particularly preferably more than 5% by mass. If it is equal to or more than the lower limit (exceeding), the obtained thermal energy is sufficiently high, and the effect of increasing the speed of elastic recovery is likely to be exhibited. On the other hand, the upper limit of the content of the light absorbing compound is preferably 50% by mass or less, more preferably 35% by mass or less, still more preferably 25% by mass or less, based on the total mass of the thermoplastic powder. It is particularly preferably less than 20% by mass. If it is below (less than) the upper limit, the resin ratio becomes relatively large, so that the property of the resin itself to recover elasticity is not hindered, and the effect of increasing the speed of elasticity recovery exerted by the addition of the light absorbing compound is obtained. Appears more.

Examples of the light absorbing compound include a photoisomerizing compound, an ultraviolet absorber, a colorant and the like. These compounds may be contained alone or in combination of two or more. When the photoisomerized compound is contained, the photoisomerized compound absorbs light and changes its structure, so that the softening rate of the thermoplastic powder is increased and the powder is easily elastically recovered. On the other hand, when an ultraviolet absorber or a colorant is contained, light can be efficiently absorbed and the absorbed light can be easily converted into heat energy, so that the softening rate of the thermoplastic powder increases. The powder can easily recover elastically. In particular, when an ultraviolet absorber is contained, photothermal conversion can be preferably performed. As described above, when the thermoplastic powder contains a compound that absorbs light, the speed of elastic recovery of the thermoplastic powder is increased, and the time required for producing the uneven pattern can be shortened.

Above all, from the viewpoint of further shortening the formation time of the uneven pattern and obtaining a clear image even at a high printing speed, the light absorbing compound preferably contains at least one of a photoisomerizing compound and an ultraviolet absorber.

Hereinafter, photoisomerization compounds, ultraviolet absorbers and colorants suitable for the present invention will be described.

≪Photoisomerizing compound≫
The photoisomerized compound refers to a compound that absorbs light and causes stereoisomerization or structural isomerization (cis-trans isomerization, photoopening reaction, etc.). Specific examples of the photoisomerized compound include an azobenzene derivative, a spiropyran derivative, a stilbene derivative and the like. Of these, compounds that cause cis-trans isomerization are preferred.

The azobenzene derivative may have a symmetrical structure or an asymmetric structure. Among them, the azobenzene derivative having an asymmetric structure is preferable because cis-trans isomerization proceeds faster by light irradiation and has an effect of further improving the rate of elastic recovery of the thermoplastic powder.

Specific examples of the azobenzene derivative include those represented by the following chemical formulas.

≪UV absorber≫
The ultraviolet absorber has an absorption wavelength in the wavelength range of 180 to 400 nm, and is deactivated by non-radiative deactivation without structural changes such as isomerization and bond cleavage from the excited state in an environment of at least 0 ° C. or higher. Refers to additives. The ultraviolet absorber may be either an organic compound or an inorganic compound as long as the conditions are satisfied. Further, an ultraviolet absorbing polymer in which a functional group having a skeleton of an organic ultraviolet absorber is incorporated into a polymer chain can also be used.

Specific examples of the ultraviolet absorber include known ones such as a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a triazine-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, and a dibenzoylmethane-based ultraviolet absorber. .. Examples of the inorganic ultraviolet absorber include titanium oxide, zinc oxide, cerium oxide, iron oxide, barium sulfate and the like.

Examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-octoxy-benzophenone, 2-hydroxy-4-dodecyloxy-benzophenone, 2-. Hydroxy-4-octadesiloxy-benzophenone, 2,2'-dihydroxy-4-methoxy-benzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, 2,2', 4,4'-tetra Hydroxy-benzophenone and the like can be mentioned.

Examples of the benzotriazole-based ultraviolet absorber include 2- (2'-hydroxy-5-methylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-t-butylphenyl) benzotriazole, and 2 -(2'-Hydroxy-3'-t-butyl-5'-methylphenyl) benzotriazole, 2,2'-methylenebis [6- (2H-benzotriazole-2-yl) -4- (1,1,1) 3,3-Tetramethylbutyl) phenol], 2- (2H-benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2- (2H-benzotriazole-2) -Il) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol and the like can be mentioned.

Examples of the triazine-based ultraviolet absorber include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine and 2,4-diphenyl-6- (2-hydroxy-4-). Ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-) Butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-) Hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl -6- (2-Hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine , [2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5- (hexyl) oxyphenol] and other hydroxyphenyltriazines, [2- [4,6-bis (2,6-bis) 4-Dimethylphenyl) -1,3,5-triazine-2-yl] -5- (octyloxy) phenol] and the like can be mentioned.

Examples of the cyanoacrylate-based ultraviolet absorber include 2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3- (3', 4'-methylenedioxyphenyl) -acrylate and the like. Can be mentioned.

Examples of the dibenzoylmethane-based ultraviolet absorber include t-butylmethoxydibenzoylmethane.

≪Coloring agent≫
As the colorant, for example, a colorant (white) using a dye of yellow, magenta, cyan, black, which is known as a colorant of toner, or inorganic particles such as titanium dioxide can be used.

As the yellow pigment, C.I. I. Dyes such as Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162; C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185 and the like.

Magenta pigments include vanadyl naphthalocyanine and C.I. I. Dyes such as Solvent Red 1, 49, 52, 58, 63, 111, 122; C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222 and the like.

As the cyan dye, C.I. I. Dyes such as Solvent Blue 25, 36, 60, 70, 93, 95; C.I. I. Pigment Blue 1, 7, 15, 60, 62, 66, 76 and the like.

Examples of the black pigment include carbon black, a magnetic substance, and iron / titanium composite oxide black, and examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black.

(Other ingredients)
The thermoplastic powder used in the original plate of the present invention is a filler, an antioxidant, an antistatic agent, a flame retardant, an adhesive-imparting agent, a dispersant, an antioxidant, as long as the object of the present invention is not impaired. It may further contain known additives such as defoaming agents, leveling agents, matting agents and light stabilizers. If the additive also corresponds to a light-absorbing compound, it shall be classified as a light-absorbing compound.

[Characteristics of thermoplastic powder]
(Shape of thermoplastic powder)
The shape of the thermoplastic powder is not particularly limited, and may be spherical, substantially spherical or other granular, elliptical, crushed, amorphous, rectangular parallelepiped or other columnar, plate-like, pyramidal-like, conical-like or the like. , Preferably granular. When granular thermoplastic powder is used, the variation in height of the thermoplastic powder arranged on the original plate is reduced. In addition, it becomes easy to arrange them regularly in the plane direction of the original plate. Therefore, the uneven pattern can be formed more precisely, and small characters and fine images can be reproduced more clearly.

(Average particle size of thermoplastic powder]
The upper limit of the volume-based median diameter of the thermoplastic powder used in the original plate of the present invention is preferably 100 μm or less in consideration of the elastic recovery of the thermoplastic powder. Above all, it is more preferably 50 μm or less, further preferably 30 μm or less, and particularly preferably 20 μm or less. When the value is not more than the upper limit, the uneven pattern can be formed more precisely, so that small characters and fine images can be reproduced more clearly. In addition, the effect can be sustained even when the plate is repeatedly rewritten. On the other hand, the lower limit of the volume-based median diameter of the thermoplastic powder is preferably 0.5 μm or more, more preferably 1 μm or more, still more preferably 2 μm or more, and particularly preferably 3 μm or more. When it is at least the lower limit value, the step of the uneven pattern becomes sufficient, and a clear pattern image can be obtained. In addition, the effect can be sustained even when the plate is repeatedly rewritten. Therefore, in a preferred embodiment of the present invention, the volume-based median diameter of the thermoplastic powder is 3 to 20 μm.

The volume-based median diameter of the thermoplastic powder is measured using a measuring device that connects a computer system equipped with the data processing software "Software V3.51" to "Multisizer 3" (manufactured by Beckman Coulter). It is calculated. Specifically, 0.02 g of the measurement sample (thermoplastic powder) is mixed with 20 mL of a surfactant solution (for the purpose of dispersing the thermoplastic powder, for example, a neutral detergent containing a surfactant component is mixed with pure water 10 times. After adding to (diluted surfactant solution) and acclimatizing, ultrasonic dispersion is performed for 1 minute to prepare a thermoplastic powder dispersion, and this thermoplastic powder dispersion is used as "ISOTONII" in the sample stand. Inject into a beaker containing (Beckman Coulter) with a pipette until the indicated concentration of the measuring device reaches 8%. Here, by setting this concentration range, it is possible to obtain a reproducible measured value. Then, in the measuring device, the number of measured particles is 25,000, the aperture diameter is 100 μm, the frequency value is calculated by dividing the measurement range of 2 to 60 μm by 256, and the volume integration fraction is 50 from the largest. % Is the volume-based median diameter.

The difference in height between the concave portion and the convex portion (step of the uneven pattern) is usually about 35 to 50% of the volume-based median diameter of the thermoplastic powder.

(Particle size distribution of thermoplastic powder)
The upper limit of the coefficient of variation (CV value, hereinafter also simply referred to as “CV value”) in the volume-based particle size distribution of the thermoplastic powder is preferably 35% or less, more preferably 25% or less, and even more preferably. Is less than 20%. When the value is not more than the upper limit, the uneven pattern can be formed more precisely, so that small characters and fine images can be reproduced more clearly. In addition, the effect can be sustained even when the plate is repeatedly rewritten. The lower limit of the CV value is not particularly limited, but is, for example, 0.5% or more. The CV value represents the degree of dispersion in the particle size distribution of the thermoplastic powder on a volume basis, and is represented by the following formula (1). The smaller the CV value, the sharper the particle size distribution, and the more uniform the sizes of the thermoplastic powders.

When the CV value is in the above range, the variation in height of the thermoplastic powder arranged on the original plate is further reduced. In addition, it becomes easy to arrange them regularly in the plane direction of the original plate. Therefore, the uneven pattern can be formed more precisely, and small characters and fine images can be reproduced more clearly. This CV value can be controlled, for example, by adjusting the amount of the aggregation terminator used in the production of the thermoplastic powder. The CV value of the thermoplastic powder can be measured by "Coulter Multisizer 3" (manufactured by Beckman Coulter Co., Ltd.) in the same manner as the volume-based median diameter.

(Average circularity of thermoplastic powder)
The average circularity of the thermoplastic powder used in the original plate of the present invention is preferably 0.930 to 1.000, more preferably 0.950 to 1.000. If it is within the above range, the thermoplastic powder is less likely to be crushed and can withstand repeated plate rewriting operations.

In the present invention, the average circularity of the thermoplastic powder is measured using "FPIA-3000" (manufactured by Sysmex Corporation).

Specifically, the sample (thermoplastic powder) is blended with an aqueous solution containing a surfactant, subjected to ultrasonic dispersion treatment for 1 minute to disperse, and then measured by "FPIA-3000" (manufactured by Sysmex). Conditions In the HPF (high magnification imaging) mode, imaging is performed at an appropriate concentration of 3,000 to 10,000 HPF detections, and the circularity is calculated for each particle constituting the thermoplastic powder according to the following formula (T). Then, the circularity of each particle is added and divided by the total number of particles.

[Manufacturing method of thermoplastic powder]
The method for producing the thermoplastic powder is not particularly limited, and examples thereof include a kneading and pulverizing method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a dispersion polymerization method, and the like, but the emulsion aggregation method is preferable. In the case of the emulsion aggregation method, it is possible to obtain a thermoplastic powder having a controlled particle size and shape. Therefore, the uneven pattern can be formed more precisely, and small characters and fine images can be reproduced more clearly. In addition, the effect can be sustained even when the plate is repeatedly rewritten.

As an example of a method for producing a thermoplastic powder containing a thermoplastic resin and a light absorbing compound by an emulsion aggregation method,
(1) Thermoplastic resin particle dispersion preparation step of dispersing the thermoplastic resin in an aqueous medium to prepare a thermoplastic resin particle dispersion;
(2) Light-absorbing compound particle dispersion preparation step of dispersing the light-absorbing compound in an aqueous medium to prepare a light-absorbing compound particle dispersion;
(3) Aggregation in which thermoplastic resin particles and light-absorbing compound particles are aggregated and fused in an aqueous medium to form aggregated particles using the dispersions obtained in (1) and (2) above. Fusing process;
(4) Aging step of aging agglomerated particles with heat energy to adjust the shape to prepare a thermoplastic powder dispersion liquid;
(5) Cooling step for cooling the thermoplastic powder dispersion;
(6) Filtering and cleaning steps in which the thermoplastic powder is solid-liquid separated from the cooled thermoplastic powder dispersion and the surfactant and the like are removed from the surface of the thermoplastic powder;
(7) Drying step of drying the washed thermoplastic powder;
Consists of.

Here, the "aqueous medium" refers to a medium composed of 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and it is preferable to use an alcohol-based organic solvent that does not dissolve the obtained resin.

Hereinafter, each step will be described.

(1) Preparation step of thermoplastic resin particle dispersion liquid In this step, a polymerizable monomer for forming a thermoplastic resin in an aqueous medium containing a surfactant having a concentration equal to or higher than the critical micelle formation concentration (CMC). , And a water-soluble polymerization initiator is added at a desired polymerization temperature while stirring, and the polymerization is carried out to prepare a thermoplastic resin particle dispersion.

Further, a polymerizable monomer for forming a thermoplastic resin is added to an aqueous medium containing a surfactant having a critical micelle concentration (CMC) or less, and mechanical energy is applied to form droplets, and then droplets are formed. It is also possible to prepare a thermoplastic resin particle dispersion liquid by adding a water-soluble radical polymerization initiator and allowing the polymerization reaction to proceed in the droplets. The oil-soluble polymerization initiator may be contained in the droplets. In such a step of preparing a thermoplastic resin particle dispersion liquid, a process of applying mechanical energy to emulsify (formation of droplets) is indispensable. Examples of the means for applying such mechanical energy include a means for applying strong stirring or ultrasonic vibration energy such as a homomixer, ultrasonic waves, and manton gorin.

The thermoplastic resin particles formed in this thermoplastic resin particle dispersion preparation step may have a structure of two or more layers made of resins having different compositions, and in this case, an emulsion polymerization treatment according to a conventional method (first). A method of adding a polymerization initiator and a polymerizable monomer to a dispersion of resin particles prepared by (one-stage polymerization) and polymerizing this system can be adopted. At this time, by performing a multi-step polymerization treatment such as second-stage polymerization and third-stage polymerization, thermoplastic resin particles having a more controlled particle size and shape can be obtained. From such resin particles, it is easy to obtain a thermoplastic powder having a controlled particle size and shape, which is preferable.

Surfactants preferably used in this step include anionic surfactants such as alkylsulfate ester salts, polyoxyethylene (n) alkyl ether sulfates, alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters and the like. Surfactant, alkylamine salt, aminoalcohol fatty acid derivative, polyamine fatty acid derivative, amine salt type such as imidazoline, alkyltrimethylammonim salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt , Tertiary ammonium salt type cationic surfactants such as benzethonium chloride, nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives, alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and Examples thereof include amphoteric surfactants such as N-alkyl-N and N-dimethylammonium betaine, and anionic surfactants and cationic surfactants having a fluoroalkyl group can also be used.

[Polymerization initiator]
As the polymerization initiator, various known polymerization initiators can be used. Specifically, for example, hydrogen peroxide, acetyl peroxide, cumil peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, peroxide. Lauroyl, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetraline hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, tert-hydroperoxide pertriphenylacetate, tert-butyl peroxide, Peroxides such as tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, tert-butyl per-N- (3-toluyl) palmitate; 2,2 '-Azobis (2-amidinopropane) hydrochloride, 2,2'-azobis- (2-amidinopropane) nitrate, 1,1'-azobis (1-methylbutyronitrile-3-sodium sulfonate), 4, Examples thereof include azo compounds such as 4'-azobis-4-cyanovaleric acid and poly (tetraethylene glycol-2,2'-azobis isobutyrate). Among these, water-soluble polymerization initiators such as ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, 2,2'-azobis (2-amidinopropane) hydrochloride, 2,2'-azobis- (2). -Amidinopropane) nitrate, 1,1'-azobis (1-methylbutyronitrile-3-sulfonic acid sodium), 4,4'-azobis-4-cyanovaleric acid can be preferably used. Further, as the polymerization initiator, a redox polymerization initiator such as persulfate and metasulfite, hydrogen peroxide and ascorbic acid can also be used.

[Chain transfer agent]
In the step of preparing the thermoplastic resin particle dispersion liquid, a chain transfer agent generally used can be used for the purpose of adjusting the molecular weight of the thermoplastic resin. The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans and mercapto fatty acid esters.

The average particle size of the thermoplastic resin particles obtained in this thermoplastic resin particle dispersion preparation step is preferably in the range of, for example, 50 to 500 nm in terms of volume-based median diameter. The volume-based median diameter was measured using "UPA-150" (manufactured by Microtrac Co., Ltd.).

(2) Preparation Step for Preparing Light Absorbent Compound Particle Dispersion The light absorption compound particle dispersion can be prepared by dispersing the light absorption compound in an aqueous medium. Since the light-absorbing compound is uniformly dispersed, the dispersion treatment of the light-absorbing compound is preferably carried out in a state where the surfactant concentration is equal to or higher than the critical micelle concentration (CMC) in the aqueous medium. As the disperser used for the dispersion treatment of the light absorbing compound, various known dispersers can be used.

The dispersion diameter of the light-absorbing compound particles in the light-absorbing compound particle dispersion prepared in this light-absorbing compound particle dispersion preparation step is preferably 10 to 300 nm, preferably 50 to 250 nm in terms of volume-based median diameter. It is more preferably 100 to 200 nm, and even more preferably 100 to 200 nm. The volume-based median diameter of the colorant particles in the colorant particle dispersion is measured by an electrophoretic light scattering photometer "ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)".

The light-absorbing compound is introduced into the thermoplastic powder by dissolving or dispersing it in a monomer solution for forming the thermoplastic resin in advance using the miniemulsion method in the above-mentioned step of preparing the thermoplastic resin particle dispersion liquid. You may.

(3) Aggregation and fusion step In this step, the thermoplastic resin particles and the light absorbing compound particles contained in the dispersion liquid formed in the above step are aggregated and fused in an aqueous medium. In this step, a thermoplastic resin particle dispersion liquid and a light absorbing compound particle dispersion liquid are added to the aqueous medium to aggregate and fuse these particles.

As a specific method for aggregating and fusing the thermoplastic resin particles and the light absorbing compound particles, an aggregating agent is added to the aqueous medium so as to have a critical aggregation concentration or higher, and then the glass transition point or higher of the thermoplastic resin particles. By heating to the above temperature, the salinization of particles such as thermoplastic resin particles and light absorbing compound particles is promoted, and at the same time, fusion is promoted in parallel. This is a method in which particle growth is stopped and heating is continuously performed in order to control the particle shape as needed.

In this method, it is preferable to quickly heat the thermoplastic resin particles to a temperature equal to or higher than the glass transition point of the thermoplastic resin particles by shortening the leaving time after adding the flocculant as much as possible. The reason for this is not clear, but there are problems that the agglutination state of the particles fluctuates and the particle size distribution becomes unstable, and the surface properties of the fused particles fluctuate depending on the leaving time after salting out. This is because there is concern that it will occur. The time until the temperature rise is usually preferably 30 minutes or less, and more preferably 10 minutes or less. The rate of temperature rise is preferably 0.5 ° C./min or higher. The upper limit of the temperature rising rate is not particularly specified, but it is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to the rapid progress of fusion. Further, after the reaction system reaches a temperature equal to or higher than the glass transition point, it is important to maintain the temperature of the reaction system for a certain period of time to continue the fusion. As a result, the growth and fusion of the particles can be effectively promoted, and the durability of the finally obtained thermoplastic powder can be improved.

[Coagulant]
The flocculant is not particularly limited, but one selected from metal salts is preferably used. Metallic salts include monovalent metal salts such as alkali metal salts such as sodium, potassium and lithium; divalent metal salts such as calcium, magnesium, manganese and copper; trivalent metal salts such as iron and aluminum. And so on. Specific examples of the metal salt include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, etc., among which agglomeration is agglomerated in a small amount. It is particularly preferable to use a divalent metal salt because it can be advanced and the agglomeration can be easily controlled. These can be used alone or in combination of two or more.

When a surfactant is used in this step, for example, the same surfactant as described above can be used as the surfactant.

(4) Aging step Specifically, in this step, the heating temperature, stirring speed, and heating time are controlled until the shape of the agglomerated particles becomes a desired average circularity by heating and stirring the system containing the agglomerated particles. This is the process of forming the thermoplastic powder. In this step, it is preferable to control the shape of the thermoplastic powder by thermal energy (heating).

(5) Cooling Step to (7) Drying Step The cooling step, filtration, cleaning step and drying step can be carried out by adopting various known methods.

[Support]
The original plate for forming an ink film of the present invention is usually formed by arranging a thermoplastic powder on the surface of a support.

The shape of the support is not particularly limited, and examples thereof include a flat plate shape and a cylindrical shape, but a cylindrical shape is preferable.

The material of the support is also not particularly limited, and is, for example, aluminum, an aluminum alloy (for example, an alloy of aluminum and magnesium or / and silicon), a metal such as iron, stainless steel, polyethylene terephthalate (PET), polybutylene terephthalate (for example). Examples thereof include plastics such as PBT), polyacrylonitrile, polyvinyl chloride, epoxy resin, phenol resin, and styrene-butadiene rubber. These may be used alone or in combination of two or more.

The support may have either a single layer or a multi-layered form. Further, in the case of multiple layers, each layer may be composed of different materials. Therefore, for example, when the support is cylindrical, the inner layer may be the above-mentioned metal and the outer layer may be the above-mentioned plastic.

[Adhesive layer]
The original plate for forming an ink film of the present invention may be one in which a thermoplastic powder is arranged on a support via an adhesive layer.

The adhesive used for forming the adhesive layer (hereinafter, also referred to as an adhesive for forming an adhesive layer) is not particularly limited, and is a curable composition containing a curable resin and, if necessary, a polymerization initiator, a solvent and the like. Is preferable.

The curable resin may be an active energy ray (for example, ultraviolet rays, visible rays, X-rays, electron beams, etc.) curable type or thermosetting type, but is preferably an active energy ray curable type, and more preferably ultraviolet rays. It is a curing type. The curable resin can be used alone or in combination of two or more. Further, as the curable resin, a commercially available product or a synthetic product may be used.

As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, an ultraviolet curable epoxy resin and the like are preferably used. Of these, ultraviolet curable urethane acrylate resin and ultraviolet curable polyol acrylate resin are preferable.

Examples of the ultraviolet curable polyol acrylate resin include ethylene glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, glycerin tri (meth) acrylate, trimethyl propanthry (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol. Examples thereof include tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and alkyl-modified dipentaerythritol penta (meth) acrylate. As the ultraviolet curable polyol acrylate resin, a commercially available product may be used, and examples of the commercially available product include Sartmer SR295, 350, 399 (manufactured by Sartmer).

As the polymerization initiator, a known photopolymerization initiator, thermal polymerization initiator, or the like can be appropriately selected depending on the type of the curable resin to be used.

As the adhesive for forming the adhesive layer, either a commercially available product or a synthetic product may be used.

The thickness of the adhesive layer (dry thickness) can be adjusted so that the ratio of the thickness to the average particle size of the thermoplastic powder (volume-based median diameter) is 1: 2 to 1: 3. preferable. Within the above range, the thermoplastic powder is firmly fixed to the adhesive layer with at least the upper half exposed from the adhesive layer. Therefore, it is possible to form an uneven pattern having a sufficient step by elastic recovery of the thermoplastic powder, and it is possible to continuously form and erase the uneven pattern. That is, a clear image can be reproduced and it can withstand repeated plate rewriting operations.

[Manufacturing method of original plate for forming ink film]
The method for producing the original plate for forming an ink film is not particularly limited, but for example, a method in which an adhesive layer is provided on a support and a thermoplastic powder is fixed on the adhesive layer is preferable.

Specifically, the above adhesive for forming an adhesive layer is applied onto a support, and a thermoplastic powder is applied onto the obtained coating film by spray coating or the like (active energy ray irradiation as necessary). The method of curing the adhesive (by heating or heating) and fixing the thermoplastic powder on the support can be mentioned.

Alternatively, an adhesive for forming an adhesive layer is applied to a first member (for example, a plastic film) constituting the support, and the thermoplastic powder is fixed on the first member in the same manner as described above, and then this is applied. It may be a method of adhering to a second support member (for example, a metal cylinder or a metal plate) so that the thermoplastic powder is exposed on the surface. At this time, the thickness of the first member can be appropriately selected according to the shape of the second member. Further, when adhering the first member and the second member, a commercially available or synthetic adhesive may be used.

When the adhesive is cured by irradiating it with active energy rays, the irradiation conditions (type of light source, irradiation intensity, irradiation time, etc.) can be appropriately selected. As the light source, a known light source such as a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, or a metal halide lamp can be used. The irradiation intensity is also not particularly limited, but is, for example, 10 to 200 mW / cm ² . The irradiation time is also not particularly limited, but is, for example, 1 to 10 minutes. Further, when the adhesive is cured by heating, the heating temperature and the heating time can be appropriately adjusted.

As a method of arranging the thermoplastic powder on the support, the thermoplastic powder and the coating liquid in which the binder is dispersed as needed are subjected to rotary coating, dipping, dripping, roll coater, blade, inkjet coater, etc. It may be applied using a liquid film coating device.

By placing the thermoplastic powder on the support and then applying pressure, the thermoplastic powder is in a stressed state, that is, in a crushed state. Further, as described above, in the case of the method of fixing the thermoplastic powder on the first member constituting the support and then adhering it to the second member constituting the support, stress is applied to the thermoplastic powder. The applying operation may be performed before or after bonding the first member and the second member.

(How to check the arrangement of thermoplastic powder)
Examples of the method for confirming the arrangement state of the thermoplastic powder in the ink film forming original plate include a method of observing the surface of the original plate with a laser microscope. Specifically, for example, a method of observing under the following observation conditions using a laser microscope (VK-X100, manufactured by KEYENCE CORPORATION) can be mentioned:
Shape observation (expert mode), no RPD, surface shape: high definition / high accuracy, magnification: 100 times, measurement range in Z direction: 50 μm (0.1 μm pitch)
The area ratio of the thermoplastic powder occupying the 90 μm × 90 μm region of the observation image is calculated, and the average area ratio of the three locations is preferably 20% or more, more preferably 30% or more, and 40% or more. Is even more preferable. When it is at least the lower limit value, the omission of the uneven pattern can be reduced, and small characters and fine images can be clearly reproduced.

Further, the thermoplastic powders are preferably arranged regularly in the plane direction of the original plate, and specifically, the average value of the distances between the centers of the adjacent thermoplastic powders is the average of the thermoplastic powders. It is more preferable that the particle size (median diameter based on volume) is 1.0 to 3.0 times. If it is within the range, the omission of the uneven pattern can be further reduced, and small characters and fine images can be reproduced more clearly. As the average value of the center-to-center distance, for example, a four-point average value L calculated by the following equation (2) by measuring the center-to-center distance of adjacent thermoplastic powders with a laser microscope can be adopted. It can be controlled within the above range by the coating conditions of the thermoplastic powder (in the case of spray coating, the spray pattern, the spray amount, the spraying distance, etc.), the concentration of the coating liquid, and the viscosity.

<Pattern film forming device and pattern film forming method>
The present invention also provides a pattern film forming apparatus (printing apparatus) using the original plate. The apparatus forms an ink film by partially irradiating the original plate with light to form a writing means for forming an uneven pattern on the surface of the original plate and applying ink to the convex or concave portions of the uneven pattern. It has an ink film forming means and a transfer means for transferring the ink film to the surface of the object to be printed. FIG. 1 is a schematic cross-sectional view showing a pattern film forming apparatus 100 according to an embodiment of the present invention. However, the pattern film forming apparatus used in the present invention is not limited to the following forms and illustrated examples.

The present invention also provides a pattern film forming method (printing method) using the above-mentioned original plate. The method includes a writing step of forming an uneven pattern on the surface of the original plate by partially irradiating the original plate with light, and applying ink to the convex or concave portions of the uneven pattern to apply an ink film on the original plate. It has an ink film forming step of forming the ink film and a transfer step of transferring the ink film to the surface of the object to be printed.

Hereinafter, each means (or step) constituting the pattern film forming apparatus (or method) according to the present invention will be described.

[Writing means (process)]
In the pattern film forming apparatus of the present invention, the writing means has, for example, as shown in FIG. 1, a writing light source 2 and, if necessary, a writing heat source 6.

By partially irradiating the ink film forming original plate 1 with light from the writing light source 2, an uneven pattern is formed on the surface of the original plate 1. In the present specification, "partially irradiating light" means irradiating either the image portion or the non-image portion of the image pattern to be written with light. In the case of the letterpress printing type, the image portion is made into a convex shape by irradiating light with the image portion as the irradiated position, and a letterpress is produced. On the other hand, in the case of the intaglio printing type, the non-image portion is set as the irradiated position and light is irradiated, and the non-image portion is formed into a convex shape so that the image portion is relatively concave and the intaglio is produced.

As the writing light source 2, a known light source may be used, but a light source such as a light emitting diode (LED) or a laser light source is particularly preferable. By using such a light source, it is possible to exhibit a photothermal conversion action caused only by light in a specific wavelength region. As a result, the effects of the present invention can be suitably exhibited, and further, power consumption can be reduced. Therefore, the light emitted in one preferred embodiment of the present invention is monochromatic synchrotron radiation. Further, one or two or more writing light sources may be installed.

The upper limit of the maximum emission wavelength of the light emitted from the writing light source 2 is preferably 850 nm or less. If it is 850 nm or less, the energy received by the thermoplastic powder is sufficient, and elastic recovery is likely to occur. Therefore, the time for forming the uneven pattern can be shortened. Of these, 550 nm or less is more preferable, 450 nm or less is even more preferable, 350 nm or less is even more preferable, and 300 nm or less is particularly preferable, because it is possible to irradiate a finer region with light and reproduce small characters and fine images more clearly. On the other hand, the lower limit of the maximum emission wavelength of the light emitted from the writing light source 2 is preferably 280 nm or more. If it is 280 nm or more, the energy received by the thermoplastic powder is not too large, so that the powder is less likely to deteriorate. Therefore, it can withstand repeated plate rewriting operations. Therefore, in the pattern film forming method according to the present invention, the light irradiated in the writing step is preferably monochromatic synchrotron radiation having a maximum emission wavelength in the wavelength range of 280 to 550 nm.

The amount of irradiation light of the writing light source 2 is preferably controlled within a range that softens the thermoplastic powder but does not dissolve it, and is preferably in the range of 1 to ^{10 J / cm 2, for example.} If it is within the above range, the thermoplastic powder deformed by the stress is elastically recovered, and becomes a convex state with respect to the portion not irradiated with light.

At the irradiated position, it is preferable to temporarily irradiate the irradiated light so that the thermoplastic powder undergoes only elastic deformation by absorbing light and then does not dissolve. This condition is easily satisfied by irradiating each part of the irradiated position with light in a pin-spot shape by scanning, and it is preferable to use the same means as the so-called electron beam drawing method. However, it is also possible to apply an irradiation method by projecting an image pattern or the like as long as the required amount of light can be supplied.

As the heat source 6 for writing, a known heat source such as an infrared lamp, a nichrome wire, or hot air can be used. When the surface of the original plate is heated to a temperature corresponding to the glass transition temperature of the thermoplastic resin (preferably 35 to 70 ° C., more preferably 40 to 65 ° C., still more preferably 45 to 60 ° C.) using the heat source 6 for writing. As compared with the case where the writing is performed by the writing light source 2 alone, the elastic recovery of the thermoplastic powder occurs faster, so that the time for forming the uneven pattern can be shortened. Therefore, a clear image can be obtained even at a high printing speed. Further, instead of installing the heat source 6 for writing, the heat source is placed on the side opposite to the surface on which the thermoplastic powder of the support is arranged (for example, when the support is cylindrical, the hollow space of the support). Even if the method of installing and heating is used, the same effect as when the heat source 6 for writing is used can be obtained. Therefore, in the pattern film forming method according to the present invention, it is preferable that the writing step includes heating the surface of the original plate. At this time, writing (light irradiation) and heating may be performed simultaneously or sequentially, but when writing (light irradiation) is performed after heating, the temperature of the original plate is changed when writing (light irradiation). It is preferable that the temperature is higher than the temperature at which the elastic recovery rate of the thermoplastic powder can be increased.

In the ink film forming original plate 1 used in the writing step, the thermoplastic powder is present on the surface of the original plate in a crushed and deformed state. By partially irradiating such an original plate with light, the powder irradiated with light recovers elastically and becomes convex with respect to the powder not irradiated with light, and the surface of the original plate 1 becomes uneven. A pattern is formed.

Therefore, the present invention also provides a method for forming an uneven pattern on the surface of the original plate by partially irradiating the original plate with light. The light irradiated in the forming method is preferably monochromatic synchrotron radiation having a maximum emission wavelength in the wavelength range of 280 to 550 nm for the same reason as described above. Further, it is preferable that the forming method further includes heating the surface of the original plate for the same reason as described above.

The writing means may be activated at least when printing different printed matter by changing the image pattern, and may not be used when printing a plurality of the same printed matter. That is, since the unevenness formed on the surface of the original plate is maintained as it is by writing once, it is possible to print a plurality of sheets without rewriting by continuously transferring the ink film by the transfer means. ..

The uneven pattern formed on the surface of the original plate 1 moves with the rotation of the original plate 1 in the direction of the arrow 21 and is used for forming the ink film.

[Ink film forming means (process)]
In the pattern film forming apparatus of the present invention, the ink film forming means includes, for example, an ink container 4 and a guide 5, as shown in FIG.

The ink film forming means applies the ink prepared in the ink container 4 to the uneven pattern formed in the writing step to form an ink film. The ink is guided to the surface of the original plate 1 by the guide 5. In the case of the letterpress printing type, an ink film is formed in the convex portion of the concave-convex pattern, and in the case of the intaglio printing type, the ink film is formed in the concave portion of the concave-convex pattern. In addition, in this specification, "ink film formation" means a predetermined position (in the case of a letterpress printing type, the upper part of a convex portion, and in the case of an intaglio printing type, the inside of a concave portion) in a state where the ink can be transferred to an object to be printed. It means to be retained.

The ink is not particularly limited as long as it can be transferred to the object to be printed 9, and known inks such as water-based inks, oil-based inks, and emulsion inks can be used.

The formed ink film moves along with the rotation of the original plate 1 in the direction of the arrow 21 and is sent so as to come into contact with the printed body 9 arranged at the downstream position. Further, the printed body 9 is fed in the direction of the arrow 23 according to the rotation (surface speed) of the original plate 1 by the rotation of the feed roller 8, and abuts each other on the lower surface portion of the original plate 1 and the abutting portions move sequentially. do.

[Transfer means (process)]
In the pattern film forming apparatus of the present invention, the transfer means has a transfer roller 10 as shown in FIG. 1, for example.

In the transfer step, the ink film formed in the ink film forming step is relatively pressed against the object to be printed 9 by the transfer roller 10 and pulled away, so that the ink film is transferred to the surface of the subject 9. As a result, the image pattern is printed on the printed object 9.

The object to be printed 9 is not particularly limited as long as the ink film is transferred, and for example, paper, a resin film, a plate-like material such as resin or metal, cloth, or the like can be used.

[Erasing means (process)]
It is preferable that the pattern film forming apparatus of the present invention further has an erasing means for pressurizing the surface of the original plate to erase the uneven pattern.

The erasing means has, for example, a pressurizing roller 3 for erasing, as shown in FIG. By pressurizing the original plate 1 after the ink film transfer with the erasing pressure roller 3, the uneven pattern is erased, and the surface of the original plate has the same flat shape as before the irradiation with light. As a result, a flat surface of the original plate without unevenness can be obtained, so that a new uneven pattern can be formed on the surface of the original plate by performing the above writing again. That is, the version can be rewritten. Further, the ink adhering to the pressure roller 3 is removed by the cleaning blade 7.

The pressurization is preferably controlled within a range in which the thermoplastic powder does not break, and is preferably performed at, for example, 10 to 100 Pa. Within the range, an appropriate stress is applied to the convex thermoplastic powder, and the powder remains in a crushed shape like the powder not irradiated with light.

Therefore, it is preferable that the pattern film forming method according to the present invention further includes an erasing step of erasing the uneven pattern by pressurizing the surface of the original plate after the transfer step.

The pattern film forming apparatus according to the present invention may have a heating means for heating the erasing means. When erasing the uneven pattern, a temperature at which the thermoplastic powder does not melt on the surface of the original plate using a heating means (for example, a temperature corresponding to the glass transition temperature of the thermoplastic resin, preferably 35 to 70 ° C., By heating to 40 to 65 ° C., even more preferably 45 to 60 ° C.), the thermoplastic powder can be transferred to the stressed state more quickly. That is, a flat original plate surface can be formed in a shorter time. Therefore, even in the case of a high printing speed, the plate can be rewritten satisfactorily, and excellent fine line reproducibility can be maintained even after the plate is repeatedly rewritten.

As the heating means, a known heat source such as an infrared lamp, a nichrome wire, or hot air can be used. For example, in FIG. 1, the heating means may be integrated with the erasing pressure roller 3 (for example, built in the erasing pressure roller 3), or may be independent of the erasing pressure roller 3. It may exist. Further, when they exist independently, the original plate 1 may be directly heated, or the pressure roller 3 may be heated to indirectly heat the original plate 1.

Therefore, in the pattern film forming method according to the present invention, it is preferable that the erasing step further includes heating the surface of the original plate. At this time, pressurization and heating may be performed simultaneously or sequentially, but it is more preferable to perform the pressurization and heating at the same time. When pressurization and heating are performed sequentially, the effect of heating can be obtained by pressurizing after heating.

By further performing the above-mentioned writing step, ink film forming step, and transfer step after the erasing step, it becomes possible to print different image patterns. Therefore, in the pattern film forming method according to the embodiment of the present invention, the uneven pattern is formed on the surface of the original plate by partially irradiating the original plate with the uneven pattern erased after the erasing step with light. An ink film forming step of applying ink to the convex or concave portions of the uneven pattern to form an ink film on the original plate, and a transfer step of transferring the ink film to the surface of the object to be printed. Further have.

The erasing means may be activated only immediately before printing different printed matter by changing the image pattern at least, and may not be used when printing a plurality of the same printed matter. That is, since the unevenness formed on the surface of the original plate is maintained as it is by writing once, it is possible to print a plurality of sheets without rewriting by continuously transferring the ink film by the transfer means. .. Further, since a plurality of types of image patterns can be repeatedly created and erased on the same original plate surface, there is an advantage that a plurality of print patterns can be performed on one original plate surface.

The pattern film forming apparatus (method) of the present invention may have means (steps) other than the above means (steps).

The effects of the present invention will be described with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Although the display of "parts" or "%" is used in the examples, it represents "parts by mass" or "% by mass" unless otherwise specified.

<Preparation of resin particle dispersion>
In a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introduction device, 9 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water were charged, and the inside was stirred at a stirring speed of 230 rpm under a nitrogen stream. The temperature was raised to 80 ° C. After raising the temperature, 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was adjusted to 80 ° C. again, and a monomer mixed solution having the following composition was added dropwise over 1 hour, and then 80. Polymerization was carried out by heating and stirring at ° C. for 2 hours to prepare a dispersion liquid (x1) of resin fine particles:
480 parts by mass of styrene 250 parts by mass of n-butyl acrylate 65 parts by mass of methacrylic acid.

Next, in a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introduction device, a solution prepared by dissolving 5 parts by mass of polyoxyethylene (2) dodecyl ether sodium sulfate in 2100 parts by mass of ion-exchanged water was placed. I prepared it. After heating the liquid temperature to 98 ° C., a solution prepared by dissolving 182 parts by mass of a dispersion liquid (x1) of resin fine particles and a monomer having the following composition at 90 ° C. was added. This was mixed and dispersed for 1 hour by a mechanical disperser "CLEARMIX" (manufactured by M-Technique Co., Ltd.) having a circulation path to prepare a dispersion liquid containing emulsified particles (oil droplets). Next, an initiator solution prepared by dissolving 4.2 parts by mass of potassium persulfate in 140 parts by mass of ion-exchanged water is added to this dispersion, and the system is heated and stirred at 84 ° C. for 1 hour to carry out polymerization. This was performed to prepare a dispersion liquid (x2) of resin fine particles:
Styrene 203 parts by mass n-butyl acrylate 68 parts by mass Methacrylic acid 12 parts by mass n-octyl-3-mercaptopropionate 1 part by mass.

Further, 280 parts by mass of ion-exchanged water was added to the dispersion liquid (x2) of the resin fine particles, and after mixing well, a solution in which 8 parts by mass of potassium persulfate was dissolved in 280 parts by mass of ion-exchanged water was added, and the temperature was 82 ° C. Under the above temperature conditions, a monomer mixed solution having the following composition was added dropwise over 1 hour. After completion of the dropping, the mixture was polymerized by heating and stirring for 2 hours, and then cooled to 28 ° C. to prepare a resin particle dispersion. The dispersion diameter of the resin particles in the obtained resin particle dispersion was 220 nm in terms of volume-based median diameter, and the glass transition temperature (Tg) was 55 ° C .:
245 parts by mass of styrene n-butyl acrylate 151 parts by mass Acrylic acid 21 parts by mass 3-octyl mercaptopropionate 6 parts by mass.

[Preparation of light-absorbing compound dispersion]
<Preparation of light absorbing compound dispersion liquid 1 (A-1)>
90 parts by mass of sodium dodecyl sulfate was added to 1600 parts by mass of ion-exchanged water. While stirring this solution, 250 parts by mass of vanadyl naphthalocyanine (maximum absorption wavelength 800 nm) was gradually added, and then dispersion treatment was performed using a stirrer "Clairemix" (manufactured by M-Technique Co., Ltd.). , A light-absorbing compound dispersion (A-1) containing vanadyl naphthalocyanine as a light-absorbing compound was prepared. The dispersion diameter of vanadyl naphthalocyanine in the obtained light-absorbing compound dispersion was 150 nm in terms of volume-based median diameter.

<Preparation of light absorbing compound dispersion liquid (A-2)>
In the preparation of the light-absorbing compound dispersion (A-1), vanadyl naphthalocyanine was added to C.I. I. Pigment Yellow 74 was used as the light-absorbing compound in the same manner as the light-absorbing compound dispersion (A-1) except that the light-absorbing compound was changed to C.I. I. A light absorbing compound dispersion (A-2) containing Pigment Yellow 74 (maximum absorption wavelength 440 nm) was prepared. C.I. in the light-absorbing compound dispersion (A-2). I. The dispersion diameter of Pigment Yellow 74 was 130 nm in terms of volume-based median diameter.

<Preparation of light-absorbing compound dispersion (A-3)>
80 parts by mass of dichloromethane and 20 parts by mass of 2,2'-dihydroxy-4-methoxy-benzophenone (maximum absorption wavelength 350 nm, Uvinul® 3049, manufactured by BASF, hereinafter simply referred to as "benzophenone") as an ultraviolet absorber. Was mixed and stirred while heating at 50 ° C. to obtain a liquid containing benzophenone. A mixed solution of 99.5 parts by mass of distilled water warmed to 50 ° C. and 0.5 parts by mass of a 20% by mass sodium dodecylbenzene sulfonate aqueous solution was added to 100 parts by mass of this solution. Then, it was emulsified by stirring at 16000 rpm for 20 minutes with a homogenizer (manufactured by Heidorff) equipped with a shaft generator 18F to obtain a benzophenone emulsified solution. The obtained benzophenone emulsion is put into a separable flask, and the organic solvent is removed by heating and stirring at 40 ° C. for 90 minutes while sending nitrogen into the gas phase, and benzophenone, which is an ultraviolet absorber as a light absorbing compound, is used. A light absorbing compound dispersion liquid (A-3) containing the above was obtained. The dispersion diameter of the benzophenone particles in the light-absorbing compound dispersion liquid (A-3) was 145 nm in terms of volume-based median diameter.

<Preparation of light-absorbing compound dispersion (A-4)>
After adding 75 mL of 2.4N hydrochloric acid to 4-aminophenol (6.54 g, 60 mmol), add a solution of sodium nitrite (4.98 g, 72 mmol) in 6 mL of distilled water while cooling and stirring at 0 ° C. , Stirring was continued at 0 ° C. for 60 minutes. A mixed solution of o-cresol (6.48 g, 60 mmol) and 24 mL of a 20% aqueous sodium hydroxide solution was added to this solution, and the mixture was stirred for 20 hours. The precipitated precipitate was filtered and the solid was washed with water. The obtained solid was purified by silica gel column chromatography using a mixed solution of ethyl acetate and hexane as a developing solvent, and recrystallized from a mixed solvent of acetone and hexane to obtain Intermediate A. To this intermediate A (2.28 g, 10 mmol), 100 mL of DMF, 1-bromohexane (9.9 g, 60 mmol) and potassium carbonate (6.9 g, 50 mmol) were added, and the mixture was stirred at 80 ° C. for 2 hours and then 20 at room temperature. Stirring for hours was continued. The solvent was distilled off under reduced pressure, the mixture was extracted with ethyl acetate, the organic layer was washed with saturated brine, and dried over anhydrous magnesium sulfate. After filtering this, the solvent was distilled off under reduced pressure, and the obtained solid substance was purified by silica gel column chromatography using a mixed solution of ethyl acetate and hexane as a developing solvent to obtain an azobenzene derivative (chemical formula) as a photoisomerized compound. 1. Maximum absorption wavelength 360 nm) was obtained. In the preparation of the light-absorbing compound dispersion (A-3), the light-absorbing compound is a photoisomerized compound in the same manner except that the benzophenone as an ultraviolet absorber is changed to the azobenzene derivative (chemical formula 1) synthesized above. A light absorbing compound dispersion (A-4) containing an azobenzene derivative (chemical formula 1) was obtained. The dispersion diameter of the azobenzene derivative particles in the light-absorbing compound dispersion liquid (A-4) was 145 nm in terms of volume-based median diameter.

[Preparation of thermoplastic powder]
<Preparation of thermoplastic powder (P-1)>
After adding 380 parts by mass (solid content equivalent) of the resin particle dispersion prepared above and 2000 parts by mass of ion-exchanged water to a reaction vessel equipped with a stirrer, a temperature sensor and a cooling tube, 5 mol / L sodium hydroxide An aqueous solution was added to adjust the pH at 25 ° C to 10. Next, an aqueous solution prepared by dissolving 60 parts by mass of magnesium chloride in 60 parts by mass of ion-exchanged water was added under stirring at 30 ° C. over 10 minutes. Then, after leaving it for 3 minutes, the temperature rise was started, the temperature of this system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size was measured using "Coulter Multisizer 3" (manufactured by Beckman Coulter Co., Ltd.), and when the volume-based median diameter reached 6.0 μm, 190 parts by mass of sodium chloride was ion-exchanged water. A dissolved aqueous solution was added to 760 parts by mass to stop particle growth. Further, the temperature is raised and the mixture is heated and stirred at 90 ° C. to promote the fusion of the particles, and when the average circularity of the thermoplastic powder reaches 0.950, 3.0 ° C./min. It was cooled to 30 ° C. at a cooling rate. The average circularity was measured using a measuring device "FPIA-2100" (manufactured by Sysmex Corporation) (the number of HPFs detected was 4000). Next, the operation of solid-liquid separation, redispersion of the dehydrated thermoplastic powder cake in ion-exchanged water, and solid-liquid separation was repeated three times for washing, and then dried at 40 ° C. for 24 hours to obtain granular thermoplasticity. A powder (P-1) was obtained. The volume-based particle size distribution (CV value) of the obtained thermoplastic powder (P-1) was 19%. The particle size distribution (CV value) was measured using "Coulter Multisizer 3" (manufactured by Beckman Coulter Co., Ltd.).

<Preparation of thermoplastic powder (P-2)>
After charging 350 parts by mass (solid content equivalent) of the resin particle dispersion prepared above and 2000 parts by mass of ion-exchanged water into a reaction vessel equipped with a stirrer, a temperature sensor and a cooling tube, 5 mol / L sodium hydroxide An aqueous solution was added to adjust the pH at 25 ° C to 10. Then, 30 parts by mass (in terms of solid content) of the light-absorbing compound dispersion (A-1) prepared above was added. Next, an aqueous solution prepared by dissolving 60 parts by mass of magnesium chloride in 60 parts by mass of ion-exchanged water was added under stirring at 30 ° C. over 10 minutes. Then, after leaving it for 3 minutes, the temperature rise was started, the temperature of this system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size was measured using "Coulter Multisizer 3" (manufactured by Beckman Coulter Co., Ltd.), and when the volume-based median diameter reached 6.0 μm, 190 parts by mass of sodium chloride was ion-exchanged water. A dissolved aqueous solution was added to 760 parts by mass to stop particle growth. Further, the temperature is raised and the mixture is heated and stirred at 90 ° C. to promote the fusion of the particles, and when the average circularity of the thermoplastic powder reaches 0.950, 3.0 ° C./min. It was cooled to 30 ° C. at a cooling rate. The average circularity was measured using a measuring device "FPIA-2100" (manufactured by Sysmex Corporation) (the number of HPFs detected was 4000). Next, the operation of solid-liquid separation, redispersion of the dehydrated thermoplastic powder cake in ion-exchanged water, and solid-liquid separation was repeated three times for washing, and then dried at 40 ° C. for 24 hours to obtain granular thermoplasticity. A powder (P-2) was obtained. The volume-based particle size distribution (CV value) of the obtained thermoplastic powder (P-2) was 20%. The particle size distribution (CV value) was measured using "Coulter Multisizer 3" (manufactured by Beckman Coulter Co., Ltd.).

<Preparation of thermoplastic powders (P-3) to (P-7)>
In the preparation of the thermoplastic powder (P-2), the granular thermoplastic powder (granular thermoplastic powder) was prepared in the same manner except that the amount of the resin particle dispersion added and the type and amount of the light absorbing compound were changed as shown in Table 1. P-3) to (P-7) were obtained.

<Preparation of thermoplastic powder (P-8)>
In the preparation of the thermoplastic powder (P-1), the granular thermoplastic powder (P-8) was prepared in the same manner except that the particle growth was stopped when the volume-based median diameter reached 2.5 μm. Got

<Preparation of thermoplastic powder (P-9)>
In the preparation of the thermoplastic powder (P-1), granular thermoplastic powder (P-9) was obtained in the same manner except that the particle growth was stopped when the volume-based median diameter reached 22 μm. rice field.

<Preparation of thermoplastic powder (P-10)>
3000 parts by mass of toluene was placed in a 5 L reaction vessel equipped with a stirrer, a temperature sensor, a flow-down condenser and a nitrogen introduction device, and the temperature was raised to the reflux temperature of toluene under a nitrogen stream. Next, a mixed solution having the following composition was added dropwise over 1 hour, and then heated and stirred at the reflux temperature for 4 hours to carry out polymerization. Then, the temperature was raised to 180 ° C., and toluene was removed under reduced pressure to obtain a styrene acrylic resin. The glass transition point (Tg) of this resin was 53 ° C .:
315 parts by mass of styrene n-butyl acrylate 159 parts by mass Methyl methacrylate 41 parts by mass 15 parts by mass of di-t-butyl peroxide.

400 parts by mass of the styrene acrylic resin obtained above was melt-kneaded by a twin-screw kneader set at a temperature of 130 ° C. After cooling and solidifying the obtained kneaded material and coarsely crushing it, a volume-based median diameter of 6.2 μm and a particle size distribution (CV value) of 26% were used using a particle collision type fine powder coarsening machine and an air flow type classifier. A thermoplastic powder (P-10) was obtained. The thermoplastic resin powder (P-10) was produced by a pulverization method.

<Preparation of thermoplastic powder (P-11)>
In the preparation of the thermoplastic powder (P-10), the thermoplastic powder (P-11) was produced in the same manner except that the styrene acrylic resin was changed to the following polyurethane resin.

(Making polyurethane resin)
After adding the following mixture to a 3 L reaction vessel, the mixture was heated and mixed at 120 ° C. This mixture was immediately poured into a tray, put into an air furnace, held at 120 ° C. for 1 hour, and then held at 130 ° C. for 5 hours to complete the reaction, and a polyurethane resin was obtained. The glass transition point (Tg) of this resin was 59 ° C.

Polyoxyethylene bisphenol A ether (Uniol (registered trademark) DA-400, manufactured by Nippon Oil & Fats Co., Ltd.) 400 parts by mass 1,3-propanediol 141 parts by mass 4,4'-diphenylmethane diisocyanate 600 parts by mass Dioctyltin laurate 0.02 Mass part.

<Preparation of thermoplastic powder (P-12)>
In the preparation of the thermoplastic powder (P-10), the thermoplastic powder (P-12) was produced in the same manner except that the styrene acrylic resin was changed to the following polyester resin.

(Making polyester resin)
The reaction was carried out by placing the following mixture in a 2 L reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen introduction device, and heating at 220 ° C. for 8 hours while stirring under a nitrogen stream. The glass transition point (Tg) of this resin was 57 ° C.

Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 246 parts by mass Polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 231 parts by mass terephthalic acid 156 parts by mass 90 parts by mass of phenylic acid Dibutyltin oxide 0.02 parts by mass.

<Preparation of thermoplastic powder adhesive layer>
UV curable resin monomer (SR350: manufactured by Sartmer) 1800 parts by mass Polymerization initiator (Irgacure (registered trademark) 819: manufactured by BASF Japan)
140 parts by mass 2-butanol 4500 parts by mass The above components were mixed and stirred to sufficiently dissolve and disperse to prepare a coating liquid for a thermoplastic powder adhesive layer. The prepared coating liquid for a thermoplastic powder adhesive layer was subjected to easy-adhesion treatment (Alacoat AP2500E: manufactured by Arakawa Chemical Industry Co., Ltd.) on both sides of a polyethylene terephthalate film stretched to a thickness of 12 μm as a support member. A film was applied on one side of the film using a bar coater so that the dry layer thickness was 2 μm.

[Preparation of original plate for forming ink film]
<Preparation of original plate (OP-1) for forming ink film>
The thermoplastic powder (P-1) prepared above was applied onto the thermoplastic powder adhesive layer prepared above by using a spray. After coating, a xenon lamp (irradiation intensity 60 mW / cm ² ) is used to irradiate ultraviolet rays from the surface not coated with the thermoplastic powder for 3 minutes, and the thermoplastic powder (P-1) is placed on the film surface. Fixed with. Then, an ultraviolet curable adhesive (SX-UV100A: manufactured by Cemedine Co., Ltd.) was applied to the back surface of the film, and the adhesive-coated surface was irradiated with a xenon lamp for 1 minute. Immediately after irradiation, it is wound around a cylindrical drum made of an aluminum / magnesium / silicon alloy having a diameter of 100 mm and a length of 500 mm as a support member and adhered, and then the surface is pressed at 40 Pa to obtain a thermoplastic powder (thermoplastic powder). An original plate (OP-1) for forming an ink film in which P-1) was arranged on the surface was prepared. Powder is present on the surface of the ink film forming original plate (OP-1) with an area ratio of 51%.

<Manufacturing of original plates (OP-2) to (OP-7) and (OP-9) to (OP-12) for forming an ink film>
In the preparation of the ink film forming original plate (OP-1), the ink film forming original plates (OP-2) to (OP) are similarly changed except that the thermoplastic powder (P-1) is changed as shown in Table 1. -7) and (OP-9) to (OP-12) were prepared. Powder is present on the surfaces of the ink film forming original plates (OP-2) to (OP-7) and (OP-9) to (OP-12) with an area ratio of 43 to 52%.

<Preparation of original plate (OP-8) for forming ink film>
In the production of the original plate for forming an ink film (OP-1), the thermoplastic powder (P-1) was changed to the thermoplastic powder (P-8), and in the production of the thermoplastic powder adhesive layer, the thermoplastic powder was prepared. The original plate for forming an ink film, except that it was applied using a spray to the thermoplastic powder adhesive layer prepared by applying it with a bar coater so that the dry layer thickness of the coating liquid for the body adhesive layer was 0.5 μm. An original plate for forming an ink film (OP-8) was produced in the same manner as in OP-1). Powder is present on the surface of the ink film forming original plate (OP-8) at an area ratio of 47%.

<Preparation of original plate (OP-13) for forming ink film>
While heating 2400 parts by mass of dichloromethane, 2400 parts by mass of toluene, 3230 parts by mass of styrene acrylic resin (X-1: manufactured by Seiko PMC), and 570 parts by mass of benzophenone (Uvinul3049, manufactured by BASF) as an ultraviolet absorber at 50 ° C. The mixture was mixed and stirred to obtain a solution containing a thermoplastic resin and an ultraviolet absorber. This solution is applied to a cylindrical drum made of an aluminum / magnesium / silicon alloy having a diameter of 100 mm and a length of 500 mm as a support member so that the dry layer thickness is 6 μm, dried, and then the surface is pressed at 40 Pa. As a result, an original plate for forming an ink film (OP-13) was prepared. The original plate for forming an ink film (OP-13) is a thermoplastic resin layer containing an ultraviolet absorber, and the thermoplastic powder is not arranged.

Table 1 shows an outline of the original plates OP-1 to OP-12 for forming an ink film.

<Example 1>
The ink film forming original plate (OP-1) installed in the pattern film forming apparatus 100 shown in FIG. 1 is irradiated with monochromatic synchrotron radiation having a wavelength of 650 nm from the writing light source 2 to the non-image portion of the image pattern A at an irradiation amount of ^{2 J / cm 2.} By irradiating with a light source, that is, an ink film forming surface (S-1) having an uneven pattern in which a non-image portion is a convex portion was formed.

<Examples 2, 3, 6-14, 17-21>
In the first embodiment, the same as in the first embodiment except that the ink film forming original plate (OP-1) and the writing method to be used are changed as shown in Table 2, the uneven pattern in which the non-image portion is a convex portion, respectively. The ink film forming surface (S-2, 3, 6-14, 17-21) on which the ink film was formed was formed.

<Example 4>
In Example 1, the portion of the original plate for forming an ink film (OP-1) to be irradiated with monochromatic synchrotron radiation having a wavelength of 650 nm is changed to the image portion of the image pattern A so that the light irradiation portion, that is, the image portion becomes a convex portion. An ink film forming surface (S-4) was formed in the same manner as in Example 1 except that an uneven pattern was formed on the surface.

<Example 5>
In the first embodiment, the unevenness in which the non-image portion becomes a convex portion is the same as in the first embodiment except that the heat source 6 for writing is operated and the surface of the original plate is heated to 55 ° C. by hot air when the light irradiation is performed. An ink film forming surface (S-5) on which a pattern was formed was formed.

<Examples 15 and 16>
In Example 5, the non-image portion becomes a convex portion in the same manner as in Example 5 except that the ink film forming original plate (OP-1) is changed to (OP-6) and (OP-7), respectively. The ink film forming surfaces (S-15) and (S-16) on which the uneven pattern was formed were formed.

<Comparative Example 1>
In Example 11, an ink film forming original plate (OP-13) was used instead of the ink film forming original plate (OP-4) to be used, and writing was performed, but the surface was not deformed and the uneven pattern was formed. Could not form. Since the original plate for forming an ink film (OP-13) has a thermoplastic resin layer, it is probable that the elastic recovery of the irradiated portion did not occur even when irradiated with light.

<Example 22>
The ink film forming original plate (OP-1) installed in the pattern film forming apparatus 100 shown in FIG. 1 is irradiated with monochromatic synchrotron radiation having a wavelength of 650 nm from the writing light source 2 to the non-image portion of the image pattern A at an irradiation amount of ^{2 J / cm 2.} By writing with the light irradiation portion, that is, the surface for forming the ink film in which the uneven pattern in which the non-image portion is a convex portion is formed is formed. The ink (water-based ink) filled in the ink container 4 is applied to the concave portions of the formed uneven pattern to form an ink film, and the paper 9 as the object to be printed is relatively pressed and separated by the transfer roller 10. The ink film was transferred to the surface of the paper and a printed image was obtained. After that, an erasing operation was performed in which the surface of the original plate was pressurized at 40 Pa with the erasing pressure roller 3, and the convex portion was deformed to the same height as the concave portion to obtain a flat surface similar to that before the writing operation. This is the same state as the original plate for forming an ink film. Subsequently, the image pattern B was written in the same manner as the writing of the image pattern A, an ink film was formed in the concave portions of the uneven pattern, and the ink film was transferred to paper to obtain a printed image. After that, an erasing operation was performed in which the surface of the original plate was pressurized at 40 Pa with the erasing pressure roller 3, and the convex portion was deformed to the same height as the concave portion to obtain a flat surface similar to that before the writing operation. By the above method, the writing-erasing of the image pattern A and the writing-erasing of the image pattern B were repeated 6 times. The printed image of the image pattern A formed the first time was used as an initial image, and the printed image of the image pattern A formed the sixth time was used as a repeated image. The rotation speed of the original plate for forming an ink film can be changed, and in the examples, the above printing was performed at speeds of 60 rpm and 100 rpm.

<Examples 23, 24, 26-46>
In Example 22, the image patterns are the same as in Example 22 except that the ink film forming original plate (OP-1) installed in the pattern film forming apparatus, the writing method, and the erasing method are changed as shown in Table 3. Initial images and repeated images of A were obtained.

In Table 3, "Yes" for writing heating indicates that the writing heat source 6 of FIG. 1 was operated and the surface of the original plate was heated to 55 ° C. with hot air during the writing operation. Further, in Table 3, "Yes" for erasing heating indicates that the erasing pressure roller 3 was operated while being heated to 55 ° C. by a heater installed inside the heating roller during the erasing operation.

<Example 25>
In Example 22, the portion to be irradiated with the writing light is changed to the image portion of the image pattern A, and the light irradiation portion, that is, the uneven pattern is formed so that the image portion becomes a convex portion, in the same manner as in Example 22. , An initial image of the image pattern A and a repeated image were obtained.
-Image pattern A
Input a pattern to write 10 lines with a width of 60 μm and a length of 10 cm at intervals of 60 μm as a write signal. ・ Image pattern B
Input a pattern to write one line with a width of 2 cm and a length of 15 cm as a write signal.

[Evaluation method]
<Thin line reproducibility>
For fine line reproducibility, the printed image of the initial image pattern A (initial) obtained above and the printed image of the image pattern A after the repetition (after the repetition) are measured with a digital microscope "VHX-600" (manufactured by KEYENCE). The line width of each thin line is measured by an indicator from the monitor image enlarged in (W1), and the rate of change of the thin line with respect to the line width of 60 μm, which is the writing signal of the measurement, is [(| W1-60 | / 60) × 100]. Calculated by (unit:%). The line width was calculated by averaging the results measured at positions of 2 cm, 5 cm, and 8 cm in the length direction. The closer the fine line change rate is to 0%, the more precisely the desired uneven pattern can be formed, and it means that small characters and fine images can be clearly formed on the object to be printed. The level at which no overlap of thin lines is visually observed is the thin line change rate of 10% or less, but if the thin line change rate is 30% or less, there is no practical problem (pass). If the rate of change of the fine lines exceeds 30%, the independence of the thin lines is impaired and the overlap is conspicuous, which poses a practical problem.

When the rewriting of the pattern A and the pattern B is not performed well, the history of the image pattern B remains in the printed image of the image pattern A after the repetition. As a result, an image is formed between the thin lines of the image pattern A, and the thin lines become thicker. Therefore, in this case, the printed image of the image pattern A after the repetition has a high fine line change rate. On the other hand, when the rewriting of the pattern A and the pattern B is performed well, such a history does not remain and an image is not formed between the fine lines of the image pattern A. Therefore, in the printed image of the image pattern A after the repetition, the fine line change rate is close to 0%. That is, it can be said that the closer the fine line change rate of the printed image after repetition is to 0%, the better the rewritability of the plate.

<Evaluation result>
As is clear from Table 3, when the pattern film forming apparatus on which the original plate of the present invention is installed is used, good fine line reproducibility is exhibited, and the effect can be sustained even after the plate is repeatedly rewritten.

1 Original plate for forming ink film (printing original plate)
2 Light source for writing 3 Pressurized roller for erasing 4 Ink container 5 Guide 6 Heat source for writing 7 Cleaning blade 8 Feed roller 9 Printed object 10 Transfer roller 21 Original plate rotation direction 22 Pressurized roller rotation direction 23 Printed object transport direction 100 patterns Film forming device.

Claims (16)

An ink film forming precursor having a thermoplastic powder containing a thermoplastic resin on the surface,
The thermoplastic powder is an original plate for forming an ink film whose shape changes in response to light energy. The original plate according to claim 1, wherein the thermoplastic powder further contains a compound that absorbs light. The original plate according to claim 2, wherein the compound has a maximum absorption wavelength in the wavelength range of 280 to 550 nm. The original plate according to claim 2 or 3, wherein the compound contains at least one of a photoisomerizing compound and an ultraviolet absorber. A method for forming an uneven pattern on the surface of the original plate by partially irradiating the original plate according to any one of claims 1 to 4 with light. The method of claim 5, further comprising heating the surface of the original plate. The method according to claim 5 or 6, wherein the irradiated light is monochromatic synchrotron radiation having a maximum emission wavelength in the wavelength range of 280 to 550 nm. A writing step of forming an uneven pattern on the surface of the original plate by partially irradiating the original plate according to any one of claims 1 to 4 with light.
An ink film forming step of applying ink to the convex or concave portions of the uneven pattern to form an ink film on the original plate.
A transfer step of transferring the ink film to the surface of the object to be printed,
A method for forming a pattern film. The pattern film forming method according to claim 8, wherein the writing step further comprises heating the surface of the original plate. The pattern film forming method according to claim 8 or 9 , wherein the light irradiated in the writing step is monochromatic synchrotron radiation having a maximum emission wavelength in the wavelength range of 280 to 550 nm. The pattern film forming method according to any one of claims 8 to 10, further comprising an erasing step of erasing the uneven pattern by pressurizing the surface of the original plate after the transfer step. The pattern film forming method according to claim 11 , wherein the erasing step further comprises heating the surface of the original plate. A writing step of forming an uneven pattern on the surface of the original plate by partially irradiating the original plate with the uneven pattern erased after the erasing step.
An ink film forming step of applying ink to the convex or concave portions of the uneven pattern to form an ink film on the original plate.
A transfer step of transferring the ink film to the surface of the object to be printed,
The pattern film forming method according to any one of claims 11 or 12, further comprising. The original version according to any one of claims 1 to 4 and
A writing means that forms an uneven pattern on the surface of the original plate by partially irradiating the original plate with light.
An ink film forming means for forming an ink film by applying ink to the convex or concave portions of the uneven pattern,
A transfer means for transferring the ink film to the surface of the object to be printed,
A pattern film forming apparatus having. The pattern film forming apparatus according to claim 14, further comprising an erasing means for pressurizing the surface of the original plate to erase the uneven pattern. The pattern film forming apparatus according to claim 15, further comprising a heating means for heating the erasing means.

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