HEAT-SENSITIVE TREATMENT-FREE PLANOGRAPHIC PRINTING PLATE MATERIAL CONTAINING THERMOSENSITIVE PROTECTION LAYER AND APPLICATION THEREOF

Abstract

Disclosed is a heat-sensitive processless planographic printing plate material containing a thermosensitive protection layer. The planographic printing plate material sequentially comprises a supporting body, a hydrophilic layer, a heat-sensitive layer and a thermosensitive protection layer from the bottom up. The thermosensitive protection layer therein can not only isolate oxygen and protect the heat-sensitive layer from oxygen inhibition, but can also sense heat and allow a polymerization reaction to take place. Thus the binding force between same and the next layer is improved, so that the precision of printing plate images is high, the development performance is good, and the pressrun is high.

Claims

1. A heat-sensitive treatment-free planographic printing plate material, wherein: the planographic printing plate material sequentially comprises a supporting body, a hydrophilic layer, a heat-sensitive layer and a thermosensitive protection layer from bottom to top; the thermosensitive protection layer comprises 40-90 parts of water-soluble resin, 10-60 parts of hydrophilic cross-linking agent and 1-30 parts of acid-producing agent; the heat-sensitive layer comprises the following components in parts by weight: 10-60 parts of film-forming resin, 30-90 parts of cross-linking agent, 0-40 parts of diluting agent, 1-30 parts of polymerization initiator, 1-10 parts of infrared absorbing dye, and 0.1-10 parts of coloring background dye; the hydrophilic layer comprises water-soluble resin, and the dry coating weight of the hydrophilic layer on the supporting body is 0.001-0.1 g/m.sup.2; and the film-forming resin in the heat-sensitive layer is one or more of oil-soluble polymer with a weight-average molecular weight of 20000-100000 and water-oil-soluble polymer with a weight-average molecular weight of 10000-200000.

2. The planographic printing plate material according to claim 1, wherein the dry coating weight of the heat-sensitive layer on the hydrophilic layer is 0.1-10 g/m.sup.2; and the dry coating weight of the thermosensitive protection layer on the heat-sensitive layer is 0.1-5 g/m.sup.2.

3. The planographic printing plate material according to claim 1, wherein the water-soluble resin in the hydrophilic layer is one or more selected from a group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, water-borne nylon resin, gelatin and cellulose derivative.

4. The planographic printing plate material according to claim 1, wherein the water-soluble resin in the thermosensitive protection layer is one or more selected from a group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, N-vinyl pyrrolidone and vinyl acetate copolymer, N-vinyl pyrrolidone and (methyl) acrylate copolymer, N-vinyl pyrrolidone and (methyl) acrylamide copolymer, N-vinyl pyrrolidone and styrene copolymer, N-vinyl amide copolymer, modified N-vinyl pyrrolidone copolymer, modified acrylate copolymer, water-borne nylon resin, gelatin and cellulose derivative.

5. The planographic printing plate material according to claim 1, wherein the hydrophilic cross-linking agent is hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, n-butyl glycidyl ether, allyl glycidyl ether, 5-ethyl hexyl glycidyl ether, phenyl glycidyl ether, cresol glycidyl ether, p-isobutyl phenyl glycidyl ether, diethyl glycidyl ether, polyethanol diglycidyl ether, polypropylene glycol diglycidyl ether, butylene glycol diglycidyl ether, trimethyl propane glycidyl ether or glycerol triglycidyl ether.

6. The planographic printing plate material according to claim 1, wherein the acid-producing agent is an acid-producing agent with an ultraviolet absorbing main peak wavelength smaller than or equal to 300 nm, including diphenyliodonium hexafluorophosphate, 1,6-p-methyl diphenyliodonium hexafluorophosphate, 1,6-p-tert-butyl diphenyliodonium hexafluorophosphate, 1,6-p-methyl diphenyliodonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate or triazine.

7. The planographic printing plate material according to claim 1, wherein: the cross-linking agent in the heat-sensitive layer is a multi-functional acrylate compound and a photopolymerizable prepolymer; the multi-functional acrylate compound is one or more of ethylene glycol dimethyl acrylate, diethylene glycol diacrylate, diethylene glycol dimethyl diacrylate, dipropylene glycol diacrylate, triethylene glycol dimethyl acrylate, tripropylene glycol diacrylate, tripropylene glycol dimethyl acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethyl acrylate, 1,4-butanediol diacrylate, bisphenol A diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, hydroxypropyl glycerol triacrylate, hydroxyethyl trimethylolpropane triacrylate, pentaerythritol tetraacrylate, di (trimethylolpropane) tetraacrylate and dipentaerythritol hexaacrylate; the diluting agent is one or more of isooctyl acrylate, isodecanoate acrylate, lauryl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate and dipropylene glycol diacrylate; the infrared absorbing dye is a benzoindole cyanine dye or a merocyanine dye; the coloring background dye is one or more of acid blue BRL, acid blue B, acid blue 2R, acid brilliant blue G, acid brilliant blue RLS, Victorian pure blue, indigo, phthalocyanine blue, methyl violet, crystal violet lactone, colorless crystal violet lactone, crystal violet lactone and indolene; and the polymerization initiator is an initiator capable of being thermally decomposed to produce free radicals and a photoinitiator with ultraviolet absorbing main peak wavelength smaller than or equal to 300 nm.

8. The planographic printing plate material according to claim 7, wherein: the oil-soluble polymer is one or more selected from a group consisting of polystyrene, polybutyl isobutylene ester, polyethyl isobutylene ester, polymethyl isobutylene ester, polymethacrylate, polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, polyvinyl acetate, polyvinyl chloride, styrene/acrylonitrile copolymer, cellulose acetate butyrate and polyvinyl butyral; and the water-oil-soluble polymer is one or more selected from a group consisting of N-vinylamide copolymer, modified N-vinylpyrrolidone copolymer and modified acrylate copolymer.

9. The planographic printing plate material according to claim 7, wherein: the initiator capable of being thermally decomposed to produce free radicals is one or more of persulfate, azodiisobutyronitrile, 2,2-azobis (2-amidinepropane) dihydrochloride, azodiisopentanitrile, azodiisoheptanitrile, azodicyclohexylcarbonitrile, dimethyl azobisisobutyrate, benzoyl peroxide, tert-butyl peroxybenzoate, lauryl peroxide and methyl ethyl ketone peroxide; and the photoinitiator with an ultraviolet absorbing main peak wavelength smaller than or equal to 300 nm is one or more of 2-hydroxy-2-methyl-1-phenylacetone, 1-hydroxycyclohexyl benzophenone, tetramethyl Michler's ketone, tetraethyl Michler's ketone, methyl ethyl Michler's ketone, diphenyliodonium hexafluorophosphate, 1,6-p-methyl diphenyliodonium hexafluorophosphate, 1,6-p-tert-butyl diphenyliodonium hexafluorophosphate, 1,6-p-methyl diphenyliodonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate and triazine.

10. The planographic printing plate material according to claim 1, wherein the heat-sensitive layer and the thermosensitive protection layer of the present invention are cured by exposure to infrared light in a wavelength range of 750-1200 nm, and a light source for the exposure comes from an infrared laser light source.

Description

DESCRIPTION OF THE EMBODIMENTS

[0078] In order to more clearly describe the present invention, the present invention will be further described below in connection with the preferred embodiments. One skilled in the art should understand that the content described below is descriptive rather than restrictive and should not limit the protection scope of the present invention.

Embodiment 1

[0079] A heat-sensitive treatment-free planographic printing plate material containing a thermosensitive protection layer is provided. The planographic printing plate material sequentially comprises a supporting body, a hydrophilic layer, a heat-sensitive layer and a thermosensitive protection layer from bottom to top.

[0080] Supporting body: an aluminum plate base pre-treated in advance and meeting the following conditions: aluminum plate base size: 1030 mm*800 mm; aluminum plate base thickness: 0.28-0.3 mm; grain specification: R.sub.a=0.5-0.6 um; R.sub.h=0.3-0.35 um; anodic oxide film weight: 3.0-3.5 g/m.sup.2.

[0081] Hydrophilic layer: a hydrophilic layer with dry coating weight of 0.02 g/m.sup.2 obtained by extrusion coating of 0.5% polyvinyl alcohol 2488 aqueous solution on the supporting body and drying for 1 minute at 100 C.

[0082] Heat-sensitive layer: a heat-sensitive layer with dry coating weight of 1.3 g/m.sup.2 obtained by extrusion coating heat-sensitive layer coating solution on the hydrophilic layer prepared above and drying for 3 minutes at 100 C.

[0083] Formula of heat-sensitive coating solution:

TABLE-US-00001 Film-forming resin (see Table 1) 3.0 g; Cross-linking agent: Multi-functional acrylate compound (see Table 1) 5.0 g; Epoxy acrylate oligomer EAO104 (provided by Shanghai 1.0 g; Polynaisse Resources Chemicals Co.) Diluting agent: Hydroxyethyl methacrylate (embodiments 1-10 and 1.0 g; comparative examples 1-9) Or diluting agent (embodiments 11-20) 0.0 g; Polymerization initiator (see Table 1) 0.4 g; Infrared absorbing dye NK-2268 0.2 g; Crystal violet lactone 0.2 g; Acid brilliant blue 0.2 g; Butanone 30 g; Propylene glycol monomethyl ether 40 g; Propylene glycol monomethyl ether acetate 20 g

[0084] Thermosensitive protection layer: a thermosensitive protection layer with dry coating weight of 1.5g/m.sup.2 obtained by extrusion coating of thermosensitive protection layer coating solution on the heat-sensitive layer prepared above and drying for 3 minutes at 100 C.

[0085] Formula of the thermosensitive protection layer coating solution:

TABLE-US-00002 Water-soluble resin (see Table 2) 0.7 g; Hydrophilic cross-linking agent (see Table 2) 0.25 g; Acid-producing agent (see table 2) 0.05 g; Surfactant FC-102 0.001 g; Pure water 50.0 g; Ethanol 50.0 g

[0086] The difference between embodiments 1-5 and embodiments 6-20 lies in that there is no hydrophilic layer between the supporting body and the heat-sensitive layer in embodiments 1-5, the heat-sensitive coating solution is directly extruded and coated on the supporting body to obtain the heat-sensitive layer, the printed plate structurally and sequentially comprises a thermosensitive protection layer, a heat-sensitive layer and a supporting body from top to bottom, and the formulas of the heat-sensitive layer coating solution and the thermosensitive protection layer coating solution are as described above.

[0087] Exposure Experiment

[0088] A Kodak Trendsetter heat-sensitive CTP plate making machine was used to expose planographic printing plate materials in the above-mentioned embodiments and comparative examples, and the exposure energy was set to 100 mJ/cm.sup.2.

[0089] Water Developability Experiment

[0090] 1) The exposed planographic printing plate materials in the above-mentioned embodiments and comparative examples were placed in pure water at 20 C. and stood for 10 seconds, and then the planographic printing plate materials were gently wiped with sponge to remove the unexposed part and leave the exposed area.

[0091] 2) Evaluation of water developability: when the unexposed part was completely removed, it was evaluated as clean, when there was a small amount of residual photosensitive layer, it was evaluated as relatively clean, and when there was a significant residual film or the developability was poor, it was evaluated as poor.

[0092] Evaluation of resolution for situations clean in the evaluation of water developability: if 2% of dots and 20 n.m fine lines were clear, it was evaluated as good; if 5% of dots and 40 n.m fine lines were clear, it was evaluated as relatively good; and if the reproducibility was more than 10% of dots, it was evaluated as poor.

[0093] Printing resistance observation was further performed for situations clean in the evaluation of water developability.

[0094] On-Printing-Machine Development Experiment

[0095] The same exposed undeveloped printing plate materials were directly hung to a printing machine, ink supply was set to zero at the beginning, and fountain solution was fully supplied to the plate to start printing. If the normal print on the premise that the plate was not dirtied could be obtained from the beginning to less than 100 pieces, the on-machine developability would be evaluated as good; if the normal print on the premise that the plate was not dirtied could be obtained from less than 200 pieces, the on-machine developability would be evaluated as relatively good; and if the normal print on the premise that the plate was not dirtied could be obtained from more than 200 pieces, the on-machine developability would be evaluated as poor.

[0096] The evaluation results obtained according to the above-mentioned method were as shown in Table 3.

TABLE-US-00003 TABLE 1 Formula of heat-sensitive layer Cross-linking Embodiment Film-forming resin agent Polymerization initiator 1 Polystyrene PETA Azodiisobutyronitrile 2 Polystyrene DPHA Azodiisobutyronitrile 3 Polystyrene PET4A Azodicyclohexylcarbonitrile 4 Polybutyl PET4A Azodicyclohexylcarbonitrile isobutylene ester 5 Polybutyl PET4A Benzoyl peroxide isobutylene ester 6 A1-2 PETA tert-butyl peroxybenzoate 7 A1-18 DEGDA Darocur 1173 8 Polyethyl DPHA Benzoyl peroxide isobutylene ester 9 Cellulose acetate DEGDA Benzoyl peroxide butyrate 10 Polymethacrylate 1,4-butanediol Darocur 1173 diacrylate 11 Polymethacrylate DPHA Irgacure184 12 A2 DPHA Methyl ethyl Michler's ketone 13 Polymethyl 1,4-butanediol Diphenyliodonium methacrylate diacrylate hexafluorophosphate 14 A3 Bisphenol A Diphenyliodonium diacrylate hexafluorophosphate 15 Polybutyl Bisphenol A 1,6-p-methyl methacrylate diacrylate diphenyliodonium hexafluorophosphate 16 Polybutyl PET4A 1,6-p-tert-butyl methacrylate diphenyliodonium hexafluorophosphate 17 polyvinyl acetate PET4A 1,6-p-methyl diphenyliodonium hexafluoroantimonate 18 Polystyrene PET4A Triphenylsulfonium hexafluorophosphate 19 Polyisobutyl DPHA Triazine methacrylate 20 Polyvinyl butyral DPHA Triazine Comparative The same as Embodiment 13 example 1 Comparative The same as Embodiment 13 example 2 Comparative The same as Embodiment 13 example 3 Comparative The same as Embodiment 13 example 4 Comparative Polyvinyl 1,4-butanediol Diphenyliodonium example 5 pyrrolidone K30 diacrylate hexafluorophosphate Comparative Polymethyl 1,4-butanediol Diphenyliodonium example 6 methacrylate (Mw diacrylate hexafluorophosphate smaller than20000) Comparative The same as Embodiment 13 example 7 Comparative The same as Embodiment 13 example 8 Comparative The same as Embodiment 13 example 9

TABLE-US-00004 TABLE 2 Formula of thermosensitive protection layer Hydrophilic cross-linking Embodiment Water-soluble resin agent Acid-producing agent 1 Polyvinyl alcohol hydroxyethyl vinyl ether Diphenyliodonium hexafluorophosphate 2 Polyvinyl pyrrolidone hydroxyethyl vinyl ether Diphenyliodonium hexafluorophosphate 3 VA 64 HBVE Diphenyliodonium hexafluorophosphate 4 VA 55 GGE Diphenyliodonium hexafluorophosphate 5 VA 37 HBVE Diphenyliodonium hexafluorophosphate 6 Polyvinyl alcohol GGE Triphenylsulfonium hexafluorophosphate 7 VA 55 + VA 64 at Butylene glycol 1,6-p-methyl mixing ratio 1:1 diglycidyl ether diphenyliodonium hexafluoroantimonate 8 VA 64 Butylene glycol 1,6-p-methyl diglycidyl ether diphenyliodonium hexafluoroantimonate 9 Hydroxypropyl methyl DVE-3 1,6-p-methyl cellulose diphenyliodonium hexafluoroantimonate 10 Hydroxyethyl cellulose BGE Triazine 11 Water-borne nylon DVE-3 Triazine resin 12 Gelatin DVE-3 Triazine 13 Carboxymethyl DVE-3 Triazine cellulose 14 A1-10 BGE Triphenylsulfonium hexafluorophosphate 15 A1-10 AGE Triphenylsulfonium hexafluorophosphate 16 A1-2 AGE Triphenylsulfonium hexafluorophosphate 17 A1-5 BPGE Triphenylsulfonium hexafluorophosphate 18 A2 BPGE Diphenyliodonium hexafluorophosphate 19 A3 PPGGE Diphenyliodonium hexafluorophosphate 20 A3 PEGGE Diphenyliodonium hexafluorophosphate Comparative Polyvinyl butyral DVE-3 Diphenyliodonium example 1 hexafluorophosphate Comparative VA 64 TPGDA Diphenyliodonium example 2 hexafluorophosphate Comparative VA 64 DVE-3 tert-butyl peroxybenzoate example 3 Comparative VA 64 DVE-3 Darocur 1173 example 4 Comparative VA 64 DVE-3 Diphenyliodonium example 5 hexafluorophosphate Comparative VA 64 DVE-3 Diphenyliodonium example 6 hexafluorophosphate Comparative Polyvinyl alcohol 0588 None None example 7 Comparative Polyvinyl alcohol 0588 DVE-3 None example 8 Comparative Polyvinyl alcohol 0588 None Diphenyliodonium example 9 hexafluorophosphate

TABLE-US-00005 TABLE 3 Evaluation results of water-developable heat-sensitive CTP plate Water Printing On-machine develop- resistance develop- Embodiment ability Resolution (prints) ability 1 Clean Good >80,000 Relatively good 2 Clean Good >80,000 Relatively good 3 Clean Good >100,000 Relatively good 4 Clean Good >80,000 Relatively good 5 Clean Good >80,000 Relatively good 6 Clean Good >50,000 Good 7 Clean Good >50,000 Good 8 Clean Good >50,000 Good 9 Clean Good >50,000 Good 10 Clean Good >50,000 Good 11 Clean Good >50,000 Good 12 Clean Good >50,000 Good 13 Clean Good >50,000 Good 14 Clean Good >50,000 Good 15 Clean Good >50,000 Good 16 Clean Good >50,000 Good 17 Clean Good >50,000 Good 18 Clean Good >50,000 Good 19 Clean Good >50,000 Good 20 Clean Good >50,000 Good Comparative Poor \ \ Poor example 1 Comparative Clean Relatively good <5,000 Good example 2 Comparative Clean Relatively good <5,000 Good example 3 Comparative Clean Relatively good <5,000 Good example 4 Comparative Clean Good <10,000 Good example 5 Comparative Clean Good <10,000 Good example 6 Comparative Clean Relatively good <3,000 Good example 7 Comparative Clean Relatively good <3,000 Good example 8 Comparative Clean Relatively good <3,000 Good example 9

[0097] Conclusion: from embodiments 1-20, it can be seen that the results of any embodiments show good water developability, good on-machine developability, good resolution and good printing resistance greater than 50,000 prints.

[0098] By comparing Table 1 and Table 2, it can be seen that comparative examples 1-4 and 7-9 adopt the same heat-sensitive layer, the difference lies in that the components of the heat-sensitive layer are different. The resin of the heat-sensitive layer in comparative example 1 is the film-forming resin described in the heat-sensitive layer, which is not water-soluble. From Table 3, it can be seen that the water developability of comparative example 1 is very poor; the hydrophilic cross-linking agent of the heat-sensitive layer in comparative example 2 is the multi-functional acrylate in the heat-sensitive layer, free radical polymerization reaction occurs, it is subjected to oxygen-caused polymerization inhibition and the degree of polymerization is limited; in comparative examples 3 and 4, the acid-producing agents in the thermosensitive protection layers are respectively the initiator described in the heat-sensitive layer, free radicals are produced after heating, and the same free radical polymerization reaction occurs, and the degree of polymerization is limited due to oxygen-caused polymerization inhibition; similarly, the components of the thermosensitive protection layer in comparative examples 7-8 are incomplete, polymerization reaction cannot occur, the infrared laser exposed and non-exposed areas cannot form a contrast, and thus it can be seen from Table 3 that the water developability of comparative examples 1-4 and 7-9 is acceptable, but the printing resistance is greatly reduced and the resolution is not as good as that of the embodiments; the thermosensitive protection layer in comparative examples 5 and 6 is consistent with that in the embodiments, but the film-forming resin of the heat-sensitive layer is not the film-forming resin of the present invention, but water-oil-soluble resin without double bonds or oil-soluble resin with a low average molecular weight is adopted, and the results show that the printing resistance is not as good as that of the embodiments. The above-mentioned results show that the combined use of the thermosensitive protection layer and the heat-sensitive layer of the present invention can ensure the water developability, and simultaneously obtain the on-machine development type printing plate with good resolution and high printing resistance.

[0099] Obviously, the above-mentioned embodiments of the present invention are merely examples to clearly describe the embodiments of the present invention, rather than limitations to the embodiments of the present invention. One skilled in the art may make other changes or variations on the basis of the above-mentioned description. It is impossible to exhaust all the embodiments here, and all obvious changes or variations derived from the technical solution of the present invention are still included in the protection scope of the present invention.