Source: https://patents.google.com/patent/US5599648A/en
Timestamp: 2018-05-24 04:27:53
Document Index: 547984091

Matched Legal Cases: ['art 5', 'art 6', 'arts 6', 'arts 5', 'arts 6', 'arts 9', 'arts 9', 'arts 9', 'arts 9', 'arts 9', 'arts 9', 'arts 9', 'arts 9', 'arts 9']

US5599648A - Surface reforming method, process for production of printing plate, printing plate and printing process - Google Patents
US5599648A
US5599648A US08157431 US15743193A US5599648A US 5599648 A US5599648 A US 5599648A US 08157431 US08157431 US 08157431 US 15743193 A US15743193 A US 15743193A US 5599648 A US5599648 A US 5599648A
US08157431
Surface reforming of a polymeric article containing a polymerizable compound is effectively performed by polymerizing the polymeric article in contact with a surface reforming medium because the transfer of the material constituting the surface reforming medium to the polymeric article is enhanced by the polymerization. The surface reforming can be performed locally selectively, i.e., imagewise. The remaining un-polymerized part may be subjected to further surface reforming, e.g., by using another type of surface reforming medium or attachment of powder, to provide an enhanced contrast of surface property. Such an enhanced contrast of surface property can be effectively used, e.g., for production of a printing plate.
This application is a continuation of application Ser. No. 07/740,630 filed Aug. 5, 1991, now abandoned.
In the use of a polymeric article, it has sometimes been practiced to reform or modify the surface properties of the polymeric article for the purpose of improving adhesiveness, scratch resistance, printability, coatability and biological affinity, provision of antistatic property, etc. Such surface reforming of a polymeric article is generally performed by modification of the surface composition, addition of a functional group, control of the surface shape, or coating with an inorganic or organic material layer. Such conventional surface reforming methods may be roughly classified into chemical reforming methods, physical reforming methods and mechanical reforming methods.
Apart from the above-mentioned conventional surface reforming methods, there is also known a mass transfer phenomenon of polytetrafluoroethylene as a phenomenon of a material being transferred to another material. This is a phenomenon whereby polytetrafluoroethylene is transferred to the surface of a polymer film or shaped product. For example, there is reported a phenomenon that polytetrafluoroethylene was transferred onto a polyethylene terephthalate film when a polytetrafluoroethylene film was caused to slightly contact the polyethylene terephthalate film, in Journal of Applied Physics, Vol. 47, No. 1, pp. 144-147 (1976). There is also reported a phenomenon that polytetrafluoroethylene was transferred to a vinyl chloride-vinyl acetate copolymer when the copolymer was thermally shaped on a substrate of polytetrafluoroethylene, in Colloid and Polymer Science, Vol. 258, No. 10, pp. 1099-1103.
On the other hand, many of the conventional physical reforming methods are performed in an vacuum atmosphere so that they require complicated apparatus and are time-consuming. Further, the irradiation with ultraviolet rays does not require a vacuum system but is only effective for formation of oxygen-containing functional groups and is not applicable to other types of reforming. Further, regarding the plasma contact treatment, the corona discharge, for example, involves a problem that the surface reformed part loses its effect in a relatively short period and does not have durability.
On the other hand, in conventional lithographic printing utilizing the immiscibility of water and oil, a hydrophilic non-image part and a hydrophobic image part are formed on a lithographic plate. At the time of printing, dampening water is applied and held at the non-image part so as to enhance the ink repulsion at the non-image part and, in this state, an oily ink is applied to the printing plate to be repulsed by the dampening water at the non-image part and selectively attached to the image part. The resultant ink image on the lithographic plate is transferred directly or indirectly through a blanket cylinder to paper, etc.
There are further known plates for Driography developed by 3M Co. using no dampening water, and waterless lithographic plates developed by Toray K. K. and Dainippon Insatsu K. K. These plates utilize an ink repulsion of a silicone rubber and are formed by disposing a silicone rubber layer on a metal sheet, such as aluminum, followed similarly by exposure and development to form an image. Further, a waterless lithographic plate using a fluorine-containing plate instead of silicone rubber has also been proposed.
As an example of the lithographic plate utilizing a silver salt, there is well known Silver Master (trade name) available from Mitsubishi Seishi K. K., which is produced through a silver salt diffusion and transfer (DTR) process. More specifically, the exposed part of the emulsion layer is caused to contain black silver to form an insoluble hydrophilic surface having a minute unevenness after development. On the other hand, silver halide at the un-exposed part is dissolved at the time of development to diffuse and migrate to the surface of the plate, thus forming a lipophilic film to provide a lithographic plate.
An object of the present invention is to provide a surface reforming method capable of reforming the entire or selectively a part of the surface of a polymeric article through a simple and quick dry treatment so that the surface property provided by the reforming can be retained for a long time.
FIG. 1 is a side view of a polymeric article used in the present invention.
FIG. 2 is a side view for illustration of a contact step wherein a surface reforming medium is caused to contact the polymeric article shown in FIG. 1 to form a laminate.
FIG. 3 is a side view for illustration of a polymerization step wherein the laminate of the polymeric article and the surface reforming medium shown in FIG. 2 is imparted with energy to cause a polymerization in the polymeric article.
FIG. 4 is a side view for illustration of a separation step wherein the surface reforming medium is separated from the polymeric article.
FIG. 5 is a side view for illustration of another embodiment of the polymerization step shown in FIG. 3.
FIG. 6 is a side view for another embodiment of the separation step shown in FIG. 4.
FIG. 7 is a side view for illustration of the contact step wherein a surface reforming medium is caused to contact a polymeric article containing a silver salt to form a laminate.
FIG. 8 is a side view for illustration of an imagewise exposure step wherein the laminate shown in FIG. 7 is imparted with a pattern of light.
FIG. 9 is a side view for illustration of a thermal development step of applying a heat to the silver salt-containing polymeric article.
FIG. 10 is a side view for illustration of a polymerization exposure step wherein the laminate of the silver salt-containing polymeric article and the surface reforming medium is imparted with light to cause a polymerization in the polymeric article.
FIG. 11 is a side view for illustration of a separation step wherein the surface reforming medium is separated from the silver salt-containing polymeric article.
FIG. 12 is a schematic side illustration of a polymeric article having a reformed surface part according to the present invention.
FIG. 13 is a side illustration of an embodiment of a printing apparatus including a printing plate produced by the present invention.
FIGS. 14 and 15 are graphs showing results of surface analysis of a polymeric article in Example 2 appearing hereinafter.
FIGS. 16 and 17 are graphs showing results of surface analysis of a polymeric article in Example 5 appearing hereinafter.
The polymeric article used in the present invention comprises at least a polymerizable compound, which causes a polymerization when provided with an energy. The polymeric article may contain a polymerization initiator as desired. The polymeric article may generally assume a form of layer 2 disposed on a support 1 as shown in FIG. 1. If the polymeric article or layer 2 has a shape-retaining property, the support 1 is unnecessary.
In order to reform the surface of the polymeric article 2, a desired surface reforming medium 4 is caused to contact the surface of the polymeric article 2 in a contact step as shown in FIG. 2. The surface reforming medium 4 may be appropriately selected depending on how the surface of the polymeric article 2 is reformed or modified.
Then, the polymeric article 2 is imparted with an energy to cause a polymerization in the polymeric article 2 in a polymerization step as shown in FIG. 3.
FIG. 3 illustrates an embodiment wherein the polymeric article 2 contains a photopolymerization initiator and is exposed to light incident from the surface reforming medium 4 side and containing a wavelength fraction absorbable by the photopolymerization initiator to polymerize the polymerizable compound in the polymeric article 2. The wavelength of light suitable for polymerizing the polymerizable compound may preferably be in the range of about 300-600 nm. If the surface reforming medium 4 lacks in light-transmissivity, the exposure may be performed from the support 1 side. When light is used as an energy in the polymerization step, at least one of the surface reforming medium 4 and the support 1 is required to be light transmissive.
In the embodiment of FIG. 3, the entire surface of the polymeric article 2 is exposed, but the polymeric article 2 can be locally selectively (pattern-wise) imparted with an energy through a mask 8. In this case, the surface of the polymeric article 2 may be locally selectively reformed depending on the pattern of the mask 8 as will be described hereinafter.
The mask 8 is not restricted to one having only a transmissive part and a non-transmissive part but can be a gradation mask having a semi-transmissive part like a photographic negative film. The gradation mask may, for example, be one formed by coating a transparent substrate with a polymer liquid crystal imparted with a pattern of transmission and scattering, a lith film or a negative film. By performing an analog exposure through such a mask, it is possible to effect a surface reforming having a gradation characteristic depending on the mask pattern. In other words, the degree of surface reforming can be changed in a gradational fashion.
In case where the polymeric article 2 contains a thermal polymerization initiator, the polymerization in the polymeric article 2 may be performed by applying heat from the surface reforming medium 4 side or the support 1 side in the polymerization step. The heating means used for this purpose may be similar to those used for the bias heating. Among the bias heating means, a heating means capable of local heating such as a thermal head or a heat pen may be used to effect a locally selective surface reforming.
After the polymerization step, the surface reforming medium 4 is separated from the polymeric article 2 to provide the polymeric article 2 with a reformed surface part in a separation step as shown in FIG. 4.
The surface reforming of the polymeric article may be performed in the above-described manner. The reformed surface part of the polymeric article depends on the part of the polymeric article polymerized in the polymerization step. When the entire surface of the polymeric article 2 is polymerized as shown in FIG. 3, the entire surface is reformed as shown in FIG. 4. When the polymeric article 2 is locally selectively polymerized by using a mask 8 as shown in FIG. 5, the surface at the polymerized part 5 is reformed, and the surface at the non-polymerized part 6 remains un-reformed as shown in FIG. 6. Accordingly, the surface reforming is performed locally selectively.
Further, if the polymeric article 2 subjected to a pattern-wise surface reforming is further subjected to the surface reforming operations according to the present invention as explained with reference to FIGS. 2 to 6, the surface of the polymeric article 2 can be reformed into a mixture of parts having different surface properties. More specifically, after peeling off the surface reforming medium 4 as shown in FIG. 6, if the polymeric article 2 subjected to the locally selective surface reforming is further covered with a surface reforming medium having a different surface reforming fraction, such as a different functional group or atom, and then again subjected to the steps described with reference to FIGS. 3 and 4, the non-polymerized parts 6 of the polymeric article 2 are polymerized to be surface-reformed in a different degree from the already polymerized parts 5, whereby the polymeric article 2 acquires a desired pattern of surface-reformed parts.
Further, after peeling off the surface reforming medium 4 as shown in FIG. 6, if the polymeric article 2 subjected to the locally selective surface reforming is further covered with a surface reforming medium having a different surface reforming fraction, such as a different functional group or atom, and then again subjected to a locally selective surface reforming as explained with reference to FIGS. 5 and 6 by using a mask having a different pattern to polymerize the un-polymerized parts 6 in a different pattern and form thereat differently surface-reformed parts. By further repeating the steps explained with reference to FIGS. 5 and 6, the polymeric article 2 can be surface-reformed in three or more degrees in a pattern.
difunctional monomers such as divinylbenzene, distyryl oxalate, distyryl malonate, distyryl succinate, distyryl glutarate, distyryl adipate, distyryl maleate, distyryl fumarate, distyryl β,β'-dimethylglutarate, distyryl 2-bromoglutarate, distyryl α,α'-dichloroglutarate, distyryl terephthalate, oxalic acid di(ethyl acrylate), oxalic acid di(methyl ethyl acrylate), malonic acid di(ethyl acrylate), malonic acid di(methyl ethyl acrylate), succinic acid di(ethyl acrylate), glutaric acid di(ethyl acrylate), adipic acid di(ethyl acrylate), maleic acid di(diethyl acrylate), fumaric acid di(ethyl acrylate), β,β'-dimethylglutaric acid di(ethyl acrylate), ethylenediacrylamide, propylenediacrylamide, 1,4-phenylenediacrylamide, 1,4-phenylenebis(oxyethyl acrylate), 1,4-phenylenebis(oxymethyl ethyl acrylate), 1,4-bis(acryloyloxyethoxy)cyclohexane, 1,4-bis(acryloyloxymethylethoxy)cyclohexane, 1,4-bis(acryloyloxyethoxycarbamoyl)benzene, 1,4-bis(acryloyloxymethylethoxycarbamoyl)benzene, 1,4-bis(acryloyloxyethoxycarbamoyl)cyclohexane, bis(acryloyloxyethoxycarbamoylcyclohexyl)methane, oxalic acid di(ethyl methacrylate), oxalic acid di(methyl ethyl methacrylate), malonic acid di(ethyl methacrylate), malonic acid di(methyl ethyl methacrylate), succinic acid di(ethyl methacrylate), succinic acid di(methyl ethyl methacrylate), glutaric acid di(ethyl methacrylate), adipic acid di(ethyl methacrylate), maleic acid di(ethyl methacrylate), fumaric acid di(ethyl methacrylate), fumaric acid di(methyl ethyl methacrylate), β,β'-dimethylglutaric acid di(ethyl methacrylate), 1,4-phenylenebis(oxyethyl methacrylate), and 1,4-bis(methacryloyloxyethoxy)cyclohexane acryloyloxyethoxyethyl vinyl ether;
tetrafunctional monomers such as ethylenetetraacrylamide, propylenetetraacrylamide, and pentaerythritol tetraacrylate; pentafunctional monomers, such as dipentaerythritol monohydroxypentaacrylate; hexafunctional monomers, such as dipentaerythritol hexaacrylate; and further oligomers or polymers having remaining terminal vinyl groups, and oligomers or polymers having side groups including reactive vinyl groups attached thereto. Two or more of these polymerizable compounds can be used in combination.
The thermal polymerization initiator may be a known initiator, examples of which may include: azo initiators and peroxide initiators. An azo initiator is an organic compound having at least one nitrogen--nitrogen double bond, and examples thereof may include: azobisisobutyronitrile, azobiscyclohexanecarbonitrile, azobismethylphenetylcarbonitrile, azobis-secamylonitrile, azobisphenylethane, azobixcyclohexylpropylonitrole, azobismethylchloroethane, tritylazobenzene, phenylazoisobutyronitrile, and 9-(p-nitrophenylazo)-9-phenylfluorene. Further, a peroxide initiator may be almost any compound having at least one oxygen--oxygen bond, and examples thereof may include: methyl ethyl ketone peroxide, cyclohexane peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide, 1,1'-bis(tert-butylperoxy)cyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, 2,2'-bis(tert-butylperoxy)butane, tert-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethylhexane-2-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, α,α'-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, succinic acid peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-toluoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxyisobutyrate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert-butyl peroxyoctanoate, tert-butyl peroxy-2,5,5-trimethylhexanoate, tert-butyl peroxylaurate, tert-butyl peroxybenzoate, di-tert-butyldiperoxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxymaleate, and tert-peroxyisopropyl carbonate. The above compounds are not exhaustive and other known thermal polymerization initiators may also be used in the present invention.
Specifically, the carbonyl compounds include diketones as exemplified by benzyl, 4,4'-dimethoxybenzyl, diacetyl, and camphorquinone; benzophenones as exemplified by 4,4'-(diethylaminobenzophenone, and 4,4'-dimethoxybenzophenone; acetophenones as exemplified by acetophenone, and 4-methoxyacetophenone; benzoin alkyl ethers; thioxanthones as exemplified by 2-chlorothioxanthone, 2,4-dichlorothixanthone, 2,4-diethylthioxanthone, and thioxanthone-3-carboxylic acid-β-methoxy ethyl ester; chalcones and styrylketones having a dialkylamino group; and cumarins as exemlified by 3,3'-carbonylbis(7-methoxycumarin), and 3,3'-carbonylbis(7-diethylaminocumarin).
polyarylate resins such as poly(4,4'-isopropylidenediphenylene-co-1,4-cyclohexylenedimethylene carbonate), poly(ethylenedioxy-3,3'-phenylene thiocarbonate), poly(4,4'-isopropylidenediphenylene carbonate-co-terephthalate), poly(4,4'-isopropylidenediphenylene carbonate), poly(4,4'-secbutylidenediphenylene carbonate), and poly(4,4'-isopropylidenediphenylene carbonate-block-oxyethylene);
It is preferred that the polymerizable compound is contained in the polymeric article 2 in a proportion of 5-99 wt. %, further preferably 10-80 wt. %, particularly preferably 20-60 wt. %, of the polymeric article 2. When a polymerization initiator is contained in the polymeric article 2, the polymerization initiator may preferably be contained in a proportion of 0.1-30 wt. parts, particularly 0.3-25 wt. parts, per 100 wt. parts of the polymerizable compound.
The shape and the size of the polymeric article 2 may be arbitrarily selected depending on the use thereof, but generally the polymeric article 2 may preferably be in the form of a layer or sheet (or film) having a thickness in the range of 0.1 micron-2 mm, particularly 1 micron-0.1 mm, except for the support 1. This thickness range is also suitable for a printing plate as will be described later.
The surface reforming medium 4 can comprise various materials depending on the nature of surface reforming. For example, in order to impart a lipophilicity or water-repelling property to the surface of the polymeric article, the surface reforming medium may comprise a resin having a low surface energy, inclusive of: fluorine-containing resins, such as polytetrafluoroethytene, tetrafluoroethyleneperfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, and poly-chlorotrifluoroethylene; and silicone resins. The surface reforming medium 4 may be formed as a film of such a resin or a coating layer of such a resin formed by applying a solution thereof in an appropriate solvent onto an appropriate substrate such as a polyethylene terephthalate film.
When the polymeric article 2 is laminated with the surface reforming medium 4 as shown in FIG. 2, it is preferred to effect the lamination under heating as by passing the polymeric article 2 and the surface reforming medium 4 in lamination through hot rollers. If the polymeric article and the surface reforming medium poorly contact each other and bubbles are allowed to remain between these members, the polymerization of the polymerizable compound can be retarded or even prevented due to quenching of radicals with oxygen thereat. If the polymerization is retarded, the degree of surface reforming may be changed locally unintentionally.
The surface reforming method using such a silver salt-containing polymeric article involves a unique polymerization step utilizing the photosensitivity of a silver halide which is different from the one already described with reference to FIG. 3. The contact or lamination step and the separation step are substantially the same as those in the surface reforming method already described with reference to FIGS. 1-6.
First, in a contact step as shown in FIG. 7, a prescribed surface reforming medium 4 is caused to contact the surface of a silver salt-containing polymeric article. The surface reforming medium 4 is identical to the one already explained hereinabove. The silver salt-containing polymeric article comprises at least a photosensitive silver salt component and a polymerizable compound, and optionally a polymerization initiator. The photosensitive silver salt component comprises at least a photosensitive silver halide, an organic silver salt and a reducing agent in the case of a dry-type one, and comprises at least a photosensitive silver halide in the case of a wet-type one, as will be described later in further detail.
The silver salt-containing polymeric article 9 may generally be formed as a layer on a support 1 as shown in FIG. 7. The support 1 is not necessary if the polymeric article 9 per se has a shape-retaining property.
It is preferred that the polymeric article 9 and the surface reforming medium 4 are caused to contact each other under heating. The heating temperature should be suppressed so as not to cause a thermal fog of the photosensitive silver salt component and may be 30° C.-120° C., preferably 35° C.-90° C., further preferably 35° C.-60° C.
In the imagewise exposure step, the polymeric article 9 is first subjected to imagewise exposure with light hν1 in a prescribed pattern. The imagewise exposure may be performed by scanning with a laser beam or by using a mask. The wavelength of the light for imagewise exposure may preferably be in the range of about 500 nm-1000 nm, further preferably about 500 nm-900 nm, in the case where the silver salt-containing polymeric article contains a sensitizing dye, and in the range of about 300 nm-500 nm in the case where the polymeric article contains no sensitizing dye.
In the polymerization step, the imagewise exposure step is followed by a thermal development step. In the thermal development step as shown in FIG. 9, the polymeric article 9 provided with a latent image in the imagewise exposure step is heated to cause a reaction between the organic silver salt and the reducing agent selectively at the exposed parts 9-a in the presence of the silver nuclei 10 acting as a catalyst, whereby the organic silver salt is converted into elemental silver 11 and the reducing agent is converted to an oxidized product 12.
The heating may depend on the composition, etc., of the polymeric article 9 but may generally be performed at 60° C.-200° C. preferably 70° C.-150° C. for 1 sec. to 7 min., preferably for 3 sec. to 60 sec. Generally, a shorter time is sufficient at a higher temperature and a longer time is required at a lower temperature. The heating may be performed by using a heating means, such as a hot plate, a heat roller or a thermal head, electrically energizing a heat generating element on the support, or by heating according to laser light irradiation.
A polymerization exposure step is placed as a final step of the polymerization step. More specifically, as shown in FIG. 10, substantially the entire face of the polymeric article 9 is uniformly exposed to light hν2. As a result, at the un-exposed parts 9-b which have not been irradiated with the light hν1 in the imagewise exposure step, the photopolymerization initiator in the polymeric article 9 is decomposed by the light hν2 to generate radicals, which causes polymerization. On the other hand, at the exposed parts 9-a in the polymeric article 9, the light hν2 is absorbed by the elemental silver 11 and/or the oxidized product 12 or radicals, even if generated by the light hν2, are quenched by the oxidized product. As a result, the polymeric article 9 is caused to have different polymer formation states between the exposed parts 9-a and the un-exposed parts 9-b to result in un-polymerized parts 9-c corresponding to the exposed parts 9-a and polymerized parts 9-d corresponding to the un-exposed parts 9-b.
The light source and the mask used in the imagewise exposure step and the polymerization exposure step are identical to those used in the surface reforming method described with reference to FIGS. 1 to 6.
It is possible to use an identical wavelength of light in the imagewise exposure step and the polymerization exposure step because a silver halide has a sufficiently higher photosensitivity than a photopolymerization initiator and can cause a sufficient latent image formation at an intensity of light not causing photopolymerization in the imagewise exposure step. For example, light in an intensity of up to about 1 mJ/cm2 may be used in the imagewise exposure step and light in an intensity of up to about 500 mJ/cm2 may be used in the polymerization exposure step, respectively measured at the surface of the polymeric article 9.
In the polymerization step, it is possible to effect the exposure at an elevated temperature of the polymeric article 9. The elevated temperature may be given by additional heating or by utilizing the remaining heat applied in the previous thermal development step. The temperature should be selected so as not to cause a redox reaction between the organic silver salt and the reducing agent. The elevated temperature can be different depending on the combination of the organic silver salt and the reducing agent but may generally be in the range of 30° C.-120° C., preferably 35° C.-90° C., further preferably 35° C.-60° C.
The peeling operation is identical to the one explained with reference to FIG. 4.
As described hereinabove, the surface reforming method using a silver salt-containing polymeric article can be regarded as identical to the surface reforming method explained with reference to FIGS. 1-6 except for the polymerization step.
As described above, the silver salt-containing polymeric article 9 is obtained by incorporating a dry-type or wet-type photosensitive silver salt component in the polymeric article 2. Accordingly, the components other than the dry-type or wet-type photosensitive silver salt component are the same as those of the polymeric article 2 described with reference to FIGS. 1-6.
The silver halide as a photosensitive salt may have a uniform crystalline structure or a multi-layer crystalline structure having locally different compositions, e.g., one having a core of AgBr covered with an outer layer of AgI. It is also possible to use simultaneously two or more kinds of silver halides having different halogen compositions, grain sizes, grain size distributions, etc.
The compounds having a mercapto group or thiocarbonyl group having α-hydrogen include 3-mercapto-4-phenyl-1,2,4-triazole, 2-mercaptobenzoimidazole, 2-mercapto-5-aminothiadiazole, 2-mercaptobenzothiazole, s-alkylthioglycolic acid (alkyl group carbon atom number of 12 to 23), dithiocarboxylic acids such as dithioacetic acid, thioamides such as thiostearoamide, and mercapto compounds such as 5-carboxy-1-methyl-2-phenyl-4-thiopyridine, mercaptotriazine, 2-mercaptobenzoxazole, mercaptooxadiazole, and 3-amino-5-benzylthio-1,2,4-triazole, which are described in U.S. Pat. No. 4,123,274.
The compounds having an imino group typically include benzotriazole or derivatives thereof, described in Japanese Patent Publication JP-B 44-30271 or JP-B 42-18416, as exemplified by benzotriazole and alkyl-substituted benzotriazoles such as methylbenzotriazole, halogen-substituted benzotriazoles such as 5-chlorobenzotriazole, carboimidobenzotriazoles such as butylcarboimidobenzotriazole, nitrobenzotriazoles, described in Japanese Laid-Open Patent Application JP-A 58-118638, sulfobenzotriazole, carboxybenxotriazole or salts thereof, or hydroxybenzotriazole, described in Japanese Laid-Open Patent Application JP-A 58-118639, 1,2,4-triazole, described in U.S. Pat. No. 4,220,709, or 1H-tetrazole, carbazole, saccharin, imidazole, and derivatives thereof.
The reducing agent used in a dry system may preferably be a compound which reduces the organic silver salt to produce elemental silver forming a black silver image and which per se is converted into an oxidation product. Such a reducing agent used in a dry system may be appropriately selected depending on the kinds of the polymerization initiator and the organic silver salt used together therewith. In the case where a photopolymerization initiator is used as the polymerization initiator, suitable examples of the reducing agent may include: monophenols, bisphenols, trisphenols, tetrakisphenols, mononaphthols, bisnaphthols, dihydroxynaphthalenes, trihydroxynaphthalenes, dihydroxybenzenes, trihydroxybenzenes, tetrahydroxybenzenes, hydroxyalkyl monoethers, ascorbic acids, 3-pyrazolidones, pyrazolines, pyrazolones, reductive salts, phenylenediamines, hydroxyamines, reductons, hydroxamic acids, hydrazines, amidoximes, and N-hydroxyureas. These reducing agents may be used singly or in combination of two or more species. Specific examples of the reducing agent are disclosed in JP-A 51-22431; U.S. Pat. Nos. 3,615,533; 3,679,426; 3,672,904; 3,751,252; 3,751,255; 3,782,949; 3,801,321; 3,794,488; 3,893,863; 3,887,376; Belgium Patent No. 786,086; U.S. Patents Nos. 3,770,448; 3,819,382; 3,773,512; 3,928,686; 3,839,048; 3,887,378; JP-B 51-35851; JP-A 50-36143; U.S. Pat. Nos. 3,827,889 and 3,756,829; JP-A 50-36110; JP-A 50-16023; JP-A 50-147711; JP-A 51-23721, JP-A 50-99719; JP-A 51-32324; JP-A 51-51933; JP-A 50-140113; JP-A 52-84727; JP-A 63-250174; and U.S. Pat. No. 3,589,903.
Suitable examples of the reducing agent used in combination with the thermal polymerization initiator may include: aminophenol derivatives, such as 1-phenyl-3-pyrazolidone (phenydone), 4-methyl-1-phenyl-3-pyrazolidone, 4,4-dimethyl-1-phenyl-3-pyrazolidone, 4-ethyl-1-phenyl-3-pyrazolidone, p (or m or o)aminophenol, 2,6-dichloro-p-aminophenol, 2,6-dimethyl-p-aminophenol, and 3,5-dimethyl-p-aminophenol; polyhydroxybenzenes or alkoxyphenols, such as catechols and alkoxyphenols. It is possible to use two or more species of these reducing agents in combination.
With respect to 1 mol of the organic silver salt, the photosensitive silver halide may preferably be used in 0.001 mol-2 mol, more preferably 0.05 mol-0.4 mol. The reducing agent may preferably be used in 0.2 mol-3 mol, more preferably 0.7 mol-1.3 mol per mol of the organic silver salt. The polymerizable compound may preferably be used in 10-1000 wt. parts, more preferably 20-500 wt. parts per 100 wt. parts of the organic silver salt. In the case where the silver salt-containing polymeric article contains the polymerization initiator, the photopolymerization or thermal polymerization initiator may preferably be used in 0.1-30 wt. parts, more preferably 0.3-25 wt. parts, per 100 wt. parts of the polymerizable compound. The polymerizable compound may preferably be contained in a proportion of 30-80 wt. %, particularly 50-70 wt. %, of the silver salt-containing polymeric article.
The polymerizable compound may preferably be used in 30-80 wt. %, particularly 50-70 wt. %, of the silver salt-containing polymeric article. In the case where the silver salt-containing polymeric article contains the polymerization initiator, the photopolymerization or thermal polymerization initiator may preferably be used in 0.1-30 wt. parts, particularly 0.3-25 wt. parts, per 100 wt. parts of the polymerizable compound. The photosensitive silver halide may preferably be used in ai proportion of 20-70 wt. %, particularly 30-50 wt. %, of the silver salt-containing polymeric article.
The silver salt-containing polymeric article can be provided with a protective layer and/or an antihalation layer similarly as in an ordinary silver salt photosensitive member.
The preservative has a function of preventing the developing agent from losing its developing power due to oxidation with oxygen dissolved from air into the aqueous solution. The preservative may preferably be sodium sulfate, sodium hydrogen-sulfite, etc.
In the wet development step, silver nuclei 10 are reduced by the developing agent in the developer liquid into elemental or metallic silver 11. It is possible to allow the un-reduced part of the photosensitive silver halide remaining in the silver salt-containing polymeric article 9, but the remaining photosensitive silver halide may be removed as desired to effect so-called fixation for stabilizing the silver image. The fixation may be performed by dipping the polymeric article within a fixing liquid after dipping within the developer liquid. The fixing liquid may contain a component for dissolving the photosensitive silver halide, which component may preferably be sodium thiosulfate or ammonium thiosulfate.
The process for producing a printing plate according to the present invention is similar to the above-described surface reforming method according to the present invention except that the surface reforming medium is composed from a material having a specific function. More specifically, the surface reforming medium used in the process for producing a printing plate according to the present invention may comprise a material having a function of imparting the plate-forming polymeric article with an enhanced wettability to water or an enhanced water-repelling property. Thus, the printing plate produced by the process of the present invention is formed by forming on the surface of the plate-forming polymeric article a pattern with a different wettability to water so as to allow the attachment of dampening water, an oily ink or a hydrophilic ink in a pattern.
On the other hand, in the case where the plate-forming polymeric article is provided with an enhanced wettability with water, the surface reforming medium may preferably comprise a hydrophilic or water-retentive material as described before.
In this instance, in order to increase the viscous adhesiveness of the un-polymerized part, it is possible to heat the plate-forming polymeric article to a temperature T in the range of T1 >T>T2, wherein T1 is a minimum temperature at which the polymerized part shows an adhesiveness and T2 is a minimum temperature at which the un-polymerized part shows an adhesiveness. The temperature T may preferably be 30° C.-200° C., further preferably be 40° C.-130° C.
Referring to FIG. 12, when such functional powder 31 is dispersed onto a partly polymerized plate-forming polymeric article 30, the powder is first placed on the entire surface of the plate-forming polymeric article 30, but powder 31 on the un-polymerized parts is attached thereto by the adhesiveness of the un-polymerized parts, while powder on the polymerized parts are just placed thereon, so that the powder 31 on the polymerized parts can be selectively removed by a simple method such as suction, blowing with air, swaying of the plate-forming polymeric article 30, use of an adhesive material showing a weaker adhesiveness than the un-polymerized part, to leave the polymeric article 30 provided with the powder 31 selectively attached to the un-polymerized parts as shown in FIG. 12.
The hydrophilic powder may comprise powder of hydrophilic materials inclusive of: metals, such as aluminum, copper, chromium, nickel, lead, iron, and zinc; oxides of magnesium, aluminum, beryllium, zinc, tin, copper, iron, etc.; natural minerals, such as kaolin clay, agalmatolite clay, dickite clay, halloysite clay, talc, sericite, mica, bentonite, smectite, montomorillonite, pumice, slate, asbestos, wolframite, diatomaceous earth, silica sand, and silica stone; fillers and pigments, such as carbon black, silica, titanium oxide, satin white and silica-alumina zeolite; plant polymers, such as guar gum, locust bean gum, gum arabic, tragacanth, carrageenan, pectin, mannan, and starch; microorganism polymers, such as xanthane gum, dextrin, succinoglucan, and curdran; animal polymers, such as gelatin, casein, albumin, and collagen; cellulose polymers such as methyl cellulose, ethyl cellulose, and hydroxyethyl cellulose; starch polymers, such as soluble starch, carboxymethyl starch, and methyl starch; alginic acid polymers, such as propylene glycol alginate, and alginic acid salts; other semisynthetic polymers, such as derivatives of polysaccharides; vinyl polymers, such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, sodium polyacrylate, and polyacrylamide; and other synthetic polymers, such as polyethylene glycol, ethylene oxide-propylene oxide block copolymer. These powders may be used singly or in combination of two or more species.
The above-mentioned hydrophilic powders not only provide a wettability to an aqueous medium, such as dampening water because of its hydrophilicity, but also provide a minute uneven surface like that of a grained PS (presensitized) plate showing a water-retentive property.
The hydrophobic or water-repellent powder may comprise powder of hydrophobic materials, inclusive of: fluorine-containing resin, such as polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, and poly(carbon-monofluoride); silicone resins; hydrophobicity-imparted silica (e.g., one known by the trade name of "Aerosil R 972", mfd. by Nihon Aerosil K. K.); vinyl resins such as polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, and polyvinyl pyrrolidone; copolymer resins such as a styrene/butadiene copolymer, a styrene-acrylonitrile copolymer, a styrene-butadiene-acrylonitrile copolymer, and a vinyl chloride-vinyl acetate copolymer; acrylic resins such as polymethyl methacrylate, polymethyl acrylate, polybutyl acrylate, and styrene-methyl methacrylate copolymer; polyesters such as polyethylene terephthalate; polyolefins such as polyethylene, polypropylene, and chlorinated polyethylene; polyamides; polyimides; epoxy resins; phenolic resins; polyarylate resins; and nylon. Among these, powder of fluorine-containing resins are particularly preferred. Any of the above powders may be used singly or in combination of two or more species.
The above-enumerated water-repellent (hydrophobic) or hydrophilic powder may preferably have an average particle size of at most 100 microns, further preferably 50-0.001 micron, particularly 1-0.05 micron, in respects of resultant image quality and handling of the powder at the time of production. The average particle size of powder described herein are based on values measured by using a super centrifuge-type automatic particle size distribution measurement apparatus (model "CAPA-700", available from Horiba Seisakusho K. K.).
The powder used in the present invention is placed into contact with dampening water at the time of printing, so that it should preferably be hardly water-soluble, particularly even at an elevated temperature (70° C. or below) realized during the printing. Herein, the term "hardly water-soluble" refers to such a solubility in water that a longer time is required for complete dissolution of the powder than the printing service time so that the resultant printed image quality is not affected by the water-solubility.
By using a lithographic printing plate thus prepared, lithographic printing can be performed by using dampening water and an oily ink, or a hydrophilic or aqueous ink. The printing apparatus used for this purpose may be a lithographic printer, suitably a small-scale one such a desktop-type or a floor-standing type offset printer, but is not necessarily restricted to the above.
Hereinbelow, an embodiment of a printing apparatus using a printing plate as prepared by the process of the present invention will be described with reference to FIG. 13.
In a printing apparatus as shown in FIG. 13, a printing plate 14 according to the present invention may be fixed about a plate cylinder 23 by means of, e.g., a chuck as used in an ordinary offset printer.
In case where the plate 14 is provided with a pattern of water-wettability, an oily ink is used as the ink 25 and, prior to the supply of the ink 25 to the plate 14, dampening water 26 in a dampening water reservoir 27 is supplied to the plate 14 through a plurality of rollers 19 along with the rotation of the cylinder 23 in the direction of an arrow A. Then, the ink 25 is supplied.
The number of the ink supply rollers 20 is not particularly limited but may be generally about 4-20 depending on the distribution and thickness of the ink. Likewise, the number of the dampening water supply rollers 19 is not particularly limited but may generally be about 2-10.
In the embodiment shown in FIG. 13, an ink supply means and a dampening water supply means are separately provided. However, it is also possible to supply the dampening water onto the ink supply rollers 20 so that the ink and the dampening water are simultaneously supplied to the plate 14. This arrangement is an advantage for compactization of the apparatus to provide a desktop offset printer.
A rotary printing apparatus has been described above, but the printing plate according to the present invention is also applicable to another-type, such as a flat-bed printing apparatus in which a plate-mounting part (corresponding to the plate cylinder 23 in the embodiment of FIG. 13) is in the form of a flat bed.
In the embodiment shown in FIG. 13, an oily or lipophilic ink is used, but it is also possible to use an aqueous or hydrophilic ink. In this case, the aqueous or hydrophilic ink is attached selectively to the easily wettable part of the plate and used for printing.
The dyes or pigments, may include inorganic or organic pigments, such as titanium oxide, carbon black, bronze powder, diazo yellow, and phthalocyanine blue. In addition to the dyes or pigments, it is also possible to use powdery coloring developer, such as powder of a binder polymer such as polystyrene in which dyes or pigments or metal powder is dispersed. The above dyes or pigments or powdery coloring developer may desirably have an average particle size of 0.1-20 microns, preferably 1-5 microns.
Further, it is possible to use an aqueous ink for printing instead of dampening water/oily ink. Such aqueous or hydrophilic ink may generally comprise a desired dye or pigment as described above, a water-soluble polymer, such as polyvinyl alcohol, polyvinylpyrrolidone or polyacrylamide, an auxiliary agent, such as a surfactant, and water as a solvent.
It is preferred that the printing plate according to the present invention is free from any remaining un-polymerized part. An improved durability is obtained when the entire surface of the printing plate has been polymerized. For this reason, if there remains any un-polymerized part after the surface reforming, the entire printing plate may preferably be imparted with light or heat to be polymerized entirely.
In the description below "ESCA (surface) analysis" means an analysis performed by using an X-ray photoelectron analyzer ("ESCA 750", available from Shimazu Seisakusho K. K.) and Mg-Kα ray at a scanning speed of 0.1 eV/sec.
Further, the contact angle measurement was performed by using a contact angle meter (Model "CAS-150", available from Kyowa Kaimen Kagaku K. K.) and by placing a water droplet with a diameter of about 1.5 mm on a polymeric article to measure the contact angle at a time of 10 seconds after the instant of the placement.
______________________________________Polyvinyl butyral resin   1     part(s)("Eslec BX-1" (trade name) mfd. bySekisui Kagaku Kogyo K.K.)Dipentaerythritol hexaacrylate                     1     part(s)("Kayarad DPHA" (trade name), mfd. byNihon Kayaku K.K.)2,4-Diethylthioxanthone   0.2   part(s)("Kayacure DETX" (trade name), mfd. byNihon Kayaku K.K.)Ethyl 4-dimethylaminobenzoate                     0.2   part(s)("Kayacure EPA" (trade name), mfd. byNihon Kayaku K.K.)Methyl ethyl ketone       13    part(s)______________________________________
A liquid having the above composition was prepared and applied onto a 50 micron-thick polyester film by an applicator and dried to form a 5-6 micron-thick polymeric article on the polyester film (Hereinafter a polymeric article in the form of a layer formed on a support is called a "polymeric layer", and the term "polymeric article" is used to rather mean a laminate structure including the polymeric layer and the support).
Then, a 50 micron-thick polytetrafluoroethylene film ("Teflon Tape TOMBO 9001", Nichiasu K. K.) was provided as a surface reforming medium and laminated onto the above polymeric layer at a nip pressure of 0.2 kg/cm2 and temperature of 80° C. by means of a laminator. Then, the polymeric layer was exposed through the polyester film for 10 sec. to fluorescent light having a peak wavelength at 380 nm from a fluorescent lamp disposed about 3 cm apart. At this time, the polymeric layer was simultaneously heated at 92° C. as a thermal bias.
As a result of the ESCA analysis of the polymeric layer, the presence of fluorine was confirmed at the polymerized part (FIG. 14) but not observed at the un-polymerized part (FIG. 15).
Then, the polymeric layer provided with the above pattern was further laminated with a polyester film at 80° C. and then subject to the whole-area exposure under the same irradiation condition as the previous exposure through a mask to complete the polymerization of the polymeric layer. As a result of the ESCA analysis, the polymeric layer showed the presence of fluorine at the first polymerized part formed at the time of exposure through the mask but did not show the presence of fluorine at the later polymerized part in lamination with the polyester film.
Two laminates each having the polymeric layer and the surface reforming medium (polytetrafluoroethylene film) in Example 1 were provided. The two laminates were respectively exposed in the same manner as in Example 1 except that one laminate was supplied with a thermal bias at 65° C. and the other laminate was supplied with a thermal bias at 92° C. similarly as in Example 1. Then, each polytetrafluoroethylene film was peeled off the two laminates.
The resultant polymeric layers were analyzed similarly as in Example 1, whereby the polymeric layer polymerized under a thermal bias at 65° C. showed a smaller fluorine peak and a contact angle of 75 degrees, while the polymeric layer polymerized under a thermal bias at 92° C. showed a larger fluorine peak and a contact angle of 98 degrees. Thus, the degree of surface reforming could be changed by changing the thermal bias temperature.
The polymeric layer in Example 1 was laminated with a 9 micron-thick vinylidene chloride resin film (available from Asahi Kasei K. K.) as a surface reforming medium at 50° C. and then exposed in the same manner as in Example 1 except that the exposure was performed for 5 sec through a negative mask having a light-transmissive part and a non-transmissive part at a thermal bias temperature of 50° C. Then, the vinylidene chloride resin film was peeled off.
As a result of the ESCA analysis, the polymeric layer showed a peak of chlorine (FIG. 16) which was not observed in the original polymeric layer at the polymerized part but did not show any chlorine peak at the non-polymerized part (FIG. 17).
______________________________________Polyvinyl butyral resin   1     part(s)("Eslec BL-2" (trade name) mfd. bySekisui Kagaku Kogyo K.K.)Trimethylolpropane triacrylate                     1     part(s)("Aronix M-309" (trade name), mfd. byToa Gosei Kagaku K.K.)2,4-Diethylthioxanthone   0.1   part(s)("Kayacure DETX" (trade name), mfd. byNihon Kayaku K.K.)Ethyl 4-dimethylaminobenzoate                     0.1   part(s)("Kayacure EPA" (trade name), mfd. byNihon Kayaku K.K.)n-Butanol                 13    part(s)______________________________________
Then, a 10%-aqueous solution of polyvinyl alcohol ("Gosenol NH-18" (trade name), mfd. by Nihon Gosei Kagaku Kogyo K. K.) was applied by means of an applicator onto a 16 micron-thick polyester film and dried to form a surface reforming medium having a 2 micron-thick polyvinyl alcohol layer.
Then, the above-prepared polymeric article and the surface reforming medium were superposed with each other so that the polymeric layer and the polyvinyl alcohol layer contacted each other, and the superposed structure was passed through hot rollers at 50° C. to form a laminate.
______________________________________Acrylic resin             1      part(s)("Dianal BR-90", Mitsubishi Rayon K.K.)Caprolactone-modified dipentaerythritol                     1      part(s)hexaacrylate("Kayarad DPCA-60", Nihon Kayaku K.K.)Benzophenone              0.05   part(s)("Kayacure-BP", Nihon Kayaku K.K.)Methyl ethyl ketone       13     part(s)______________________________________
Then, a 10%-thermal solution of hydroxypropylcellulose ("HPC-SL", Nihon Soda K. K.) was applied onto a 16 micron-thick polyester film otherwise in the same manner as in Example 6 to form a surface reforming medium.
Then, the polymeric article and the surface reforming medium were laminated with each other in the same manner as in Example 6. The polymeric layer was then subjected to exposure for 5 sec through a negative mask having a light-transmissive part and a non-transmissive part from a high-voltage mercury lamp (Model "BS-7" (trade name), mfd. by Mikasa K. K.) disposed so as to provide an irradiation intensity at the surface of 5 mW/cm2 with application of a thermal bias at 54° C. Then, the surface reforming medium was peeled off to obtain a surface-reformed polymeric layer.
The liquid composition used in Example 6 was applied by an applicator onto a 100 micron-thick polycarbonate film to form a lithographic plate blank having a 5-6 micron-thick polymeric layer.
The thus obtained lithographic plate was fixed about the plate cylinder of a desktop-type offset printer ("San-Offset" (trade name), mfd. by San Insatsu Kikai K. K.), and printing was performed on coated paper by using an oily ink ("New Champion AT 185 Black", mfd. by Dai Nippon Ink K. K.) and dampening water (6-times dilution of an etch liquid available from Gestetner Ltd.), whereby black images identical to the mask pattern were obtained.
A lithographic plate blank was prepared in the same manner as in Example 8.
Then, a surface reforming medium was prepared applying onto a polyester film the following liquid composition by means of a wire bar so as to provide a dry thickness of 5-6 microns.
______________________________________Acrylonitrile-polyoxyalkylene                      5     part(s)copolymerWater-dispersible acrylic resin                      40    part(s)("Acryset EX-14", Nihon Shokubai Kagaku K.K.)Surfactant                 10    part(s)("Emulgen 909", Kao K.K.)Butyl cellosolve           10    part(s)Deionized water            35    part(s)______________________________________
Referring to FIG. 13, the plate 14 thus prepared was fixed about a plate cylinder 23, the ink used 24 in Example 8 and dampening water (deionized water) 26 were placed in an ink fountain 25 and an ink reservoir 27, respectively, and an apparatus as shown was brought into operation. As a result, the dampening water was first supplied to the plate 14 through dampening water supply rollers 19 and then the ink 24 was supplied to the plate through ink supply rollers 20. Then, when the plate 14 (on the plate cylinder 23) was caused to contact a blanket cylinder 15, the ink was transferred and attached to the blanket cylinder and then transferred to plain paper 17 which was supplied from a cassette 21 through a roller 16, when the paper passed between the blanket roller 15 and an impression roller 18, whereby prints were obtained.
______________________________________Silver bromide           0.7    part(s)Silver behenate          4.5    part(s)Behenic acid             2.5    part(s)Phthalazinone            1.0    part(s)4,4'-Methylenebis(2-methyl-1-naphthol)                    3.2    part(s)Polyvinyl butyral resin  5.0    part(s)("Eslec BL-2", Sekisui Kagaku K.K.)Dipentaerythritol hexaacrylate                    10     part(s)("Kayarad DPHA", Nihon Kayaku K.K.)3,3'-Carbonylbis(7-diethylamino-                    0.3    part(s)coumarin)Ethyl 4-dimethylaminobenzoate                    0.2    part(s)("Kayacure EPA", Nihon Kayaku)Xylene/n-butanol (7/3)   150    part(s)______________________________________
Then, a 10%-aqueous solution of polyvinyl alcohol ("Gosenol NH-18" (trade name), mfd. by Nihon Gosei Kagaku Kogyo K. K.) was applied by means of an applicator onto a 9 micron-thick polyester film and dried to form a surface reforming medium having a 2 micron-thick polyvinyl alcohol layer.
Then, the above-prepared silver salt-containing polymeric article and the surface reforming medium were superposed with each other so that the polymeric layer and the polyvinyl alcohol layer contacted each other, and the superposed structure was passed through hot rollers at 50° C. to form a laminate.
Then, on the surface reforming medium in the thus-prepared laminate of the silver salt-containing polymeric article/surface reforming medium, a negative mask having a light-transmissive part and a non-transmissive part was placed in alignment, and imagewise exposure was performed for 0.5 sec from a tungsten lamp 5 cm spaced apart. then, the negative mask was removed, and the laminate was passed through a thermal developing apparatus at 120° C. in 20 sec. Then, the laminate was placed on a hot plate heated at 65° C., and exposed for 10 sec to fluorescent light having a peak at 420 nm from a fluorescent lamp 3 cm space apart, thereby to form a polymerization image in the silver salt-containing polymeric layer.
The lithographic plate was then fixed about the plate cylinder of a desktop-type offset printer ("San-Offset" (trade name), mfd. by San Insatsu Kikai K. K.), and printing was performed on coated paper by using an oily ink ("New Champion AT 185 Black", mfd. by Dai Nippon Ink K. K.) and dampening water (6-times dilution of an etch liquid available from Gestetner Ltd.), whereby black images identical to the mask pattern were obtained.
A printing plate according to the present invention was prepared in the same manner as in Example 11 except that the surface reforming medium having a polyvinyl alcohol layer was replaced by a surface reforming medium prepared by coating a 9 micron-thick polyester film with a 10%-ethanol solution of hydroxycellulose ("HPC-SL", mfd. by Nihon Soda K. K.) by an applicator form a 2 micron-thick dry coating layer.
______________________________________Acrylonitrile-polyoxyalkylene                      5     part(s)copolymerWater-dispersible acrylic resin                      40    part(s)("Acryset EX-14", Nihon Shokubai Kagaku K.K.)Surfactant ("Emulgen 909", Kao K.K.)                      10    part(s)Butyl cellosolve           10    part(s)Deionized water            35    part(s)______________________________________
______________________________________Silver bromide            1.1    part(s)Silver behenate           6.8    part(s)Behenic acid              3.8    part(s)Phthalazinone             1.5    part(s)4,4'-Methylenebis(2,6-di-tert-                     4.8    part(s)butylphenolSynthetic silica          7.5    part(s)("Mizukasil p-526", Mizusawa Kagaku K.K.)Water-dispersible acrylic resin                     40     part(s)("Acryset EX-14", Nihon Shokubai Kagaku K.K.)Surfactant ("Emulgen 909", Kao K.K.)                     10     part(s)Butyl cellosolve          40     part(s)Deionized water           140    part(s)Epoxy acrylate            7.5    part(s)("Kayarad R-167", Nihol Kayaku K.K.)Pentaerythritol triacrylate                     7.5    part(s)("Kayarad PET-30", Nihon Kayaku K.K.)2,4-Diethylthioxanthone   0.7    part(s)("Kayacure DETX", Nihon Kayaku)Ethyl 4-dimethylaminobenzoate                     0.7    part(s)("Kayacure EPA", Nihon Kayaku)______________________________________
Then, a polytetrafluoroethylene tape ("Teflon Tape TOMBO 9001", Nichiasu K. K.) as a surface reforming medium was superposed on the silver salt-containing polymeric layer of the polymeric article, and the superposed structure was passed through hot rollers at 70° C. to form a laminate.
Then, a negative mask was aligned on the polyester film support of the laminate, and imagewise exposure and thermal development were performed similarly as in Example 11. Then, the laminate was placed on a hot plate at 75° C. and subjected to 25 sec of whole-area exposure to fluorescent light having a peak at 380 nm from a fluorescent lamp to form a polymerization image in the polymeric layer. Then, after removing the surface reforming medium, the silver salt-containing polymeric article was subjected 60 seconds of further whole-area exposure by using the above fluorescent lamp and hot plate to form a printing plate according to the present invention.
______________________________________Silver bromide           0.6    part(s)Silver behenate          5.0    part(s)Behenic acid             2.0    part(s)Phthalazinone            0.8    part(s)1,1'-Bis(2-hydroxy-3,5-dimethyl-                    2.5    part(s)phenyl)-3,3-dimethylpropane1-Carboxymethyl-5-[(3-ethyl-                    0.001  part(s)naphtho[1,2-d]oxazoline-2-indene)-dethylidene]-3-ethylthiohydantoinXylene/n-butanol (1/1)   90     part(s)Polyvinyl butyral resin  3.0    part(s)("Eslec BM-2", Sekisui Kagaku K.K.)Acrylic resin            3.0    part(s)("Dianol BR-77", Mitsubishi Rayon K.K.)Dipentaerythritol hexaacrylate                    3.0    part(s)("Kayarad DPHA", Nihon Kayaku)Benzyl dimethyl ketal    0.3    part(s)("Irgacure 651", Ciba-Geigy Corp.)______________________________________
Then, the surface reforming medium comprising a coating layer containing an acrylonitrilepolyoxyalkylene copolymer on a polyester film used in Example 13 was superposed on the polymeric layer of the silver salt-containing polymeric article prepared above, and the superposed structure was passed through hot rollers at 50° C. to form a laminate.
Then, the laminate was subjected to imagewise exposure by using a drum scan-type laser beam printer (mfd. by Abe Sekkei K. K.) equipped with an He--Ne laser (output: 5 mW), then heated for 5 sec. at 125° C. to form a silver image at the exposed parts of the silver salt-containing polymeric layer, and then subjected to 20 sec of whole-area exposure on a hot plate at 75° C. to fluorescent light having a peak at 340 nm from a fluorescent lamp 3 cm spaced apart to polymerize the part of the silver salt-containing polymeric layer except for the parts with the silver image to obtain a polymerization image. Then, the surface reforming medium was peeled off, and the remaining silver salt-containing polymeric article was subjected to additional 90 sec of whole-area exposure from a distance of 3 cm by using the above fluorescent lamp and hot plate, to obtain a printing plate.
A silver salt-containing polymeric article was prepared in the same manner as in Example 15 except that the polyvinyl butyral resin was replaced by a different type of polyvinyl butyral resin ("BX-1", Mitsubishi Rayon K. K.).
Then, the preparation of the printing plate in Example 15 was followed up to the separation of the surface reforming medium. Separately, an additional surface reforming medium (surface reforming medium (B)) was prepared by coating a 9 micron-polyester film with a 1 micron-thick layer of fluorine-containing resin ("Fluorad FC-721", Sumitomo 3M K. K.). Then, the surface reforming medium (B) was further laminated onto the polymeric layer having a polymerization image of the silver salt-containing polymeric article by using hot rollers at 50° C., followed by 90 sec. of whole-area exposure by the fluorescent lamp, and the separation of the surface reforming medium (B) similarly as in Example 15, to obtain a printing plate.
A printing plate was prepared in the same manner as in Example 16, except for exchanging the order of two types of surface reforming media, i.e., first by using the surface reforming medium (B) having a coating layer of fluorine-containing resin for the imagewise exposure, thermal development and whole-area exposure, and then using the surface reforming medium having a coating layer containing the acrylnitrilepolyoxyalkylene copolymer for whole-area exposure. The resultant printing plate showed contact angles of 120 degrees and 16 degrees at the reversed image parts.
A printing plate was prepared in the same manner as in Example 16 except that the polyvinyl butyral resin was replaced by a different type of polyvinyl butyral resin having a higher Tg (glass transition point) ("KS-I", Mitsubishi Rayon K. K.).
Silver halide particles consisting of 75 mol. of silver chloride, 24.5 mol. % of silver bromide and 0.5 mol. % of silver iodide were formulated together with gelatin, and then subjected to sulfur-sensitization and gold-sensitization according to ordinary methods. The silver halide particles showed an average particle size of 0.20 micron. A merocyanine dye showing a maximum sensitivity at 550 mu was added as a sensitizing dye and tolylene 2,4-diisocyanate was added as a hardening agent in an amount of about 0.5 g per 100 g of gelatin, followed further by addition of appropriate stabilizer and surfactant to obtain a photosensitive liquid (I).
______________________________________Photosensitive liquid (I)  1     part(s)Polyvinyl alcohol          1     part(s)("Gosenol NH-18", mfd. by Nihon GoseiKagaku K.K.)Pentaerythritol triacrylate                      1     part(s)("Kayacure DETX", mfd. by Nihon Kayaku K.K.)Ethyl 4-dimethylaminobenzoate                      0.1   part(s)("Kayacure EPA", mfd. by Nihon Kayaku K.K.)Water/n-butanol            10    part(s)______________________________________
The coating liquid was applied by an applicator onto a 50 micron-thick polyester film to provide a 5 micron-thick silver salt-containing polymeric layer containing 0.3 g each of gelatin and silver per m2.
Onto the silver salt-containing polymeric article thus prepared, the surface reforming medium (B) prepared in Example 16 was laminated similarly as in Example 16, followed by placement of a negative mask thereon, 1 sec. of imagewise exposure from a tungsten lamp 5 cm spaced apart, separation of the negative mask, and 4 min. of dipping of the laminate in a developing liquid having the following composition at 40° C.:
______________________________________p-Methoxy phenol          12     part(s)Sodium sulfite            7      part(s)Sodium carbonate          5      part(s)Potassium bromide         0.1    part(s)β-acetylphenylhydrazine                     0.3    part(s)Water                     1000   part(s)(Sodium hydroxide for adjustment of pH 10)______________________________________
The lithographic plate was used for printing in the same manner as in Example 11, whereby sharp black images free from fog at the non-image parts were obtained similarly as in Example 16.
______________________________________Polyvinyl butyral resin   1     part(s)("Eslec BL-2", Sekisui Kagaku K.K.)Trimethylolpropane triacrylate                     1     part(s)("Kayarad TMPTA", Nihon Kayaku K.K.)2,4-Diethylthioxanthone   0.2   part(s)("Kayacure DETX", Nihon Kayaku K.K.)Ethyl 4-dimethylaminobenzoate                     0.2   part(s)("Kayacure EPA", Nihon Kayaku K.K.)n-Butyral                 16    part(s)______________________________________
A liquid having the above composition was prepared and applied by an applicator onto a 100 micron-thick polycarbonate film ("Panlite", Teijin Kasei K. K.) in a dry thickness of 10 microns to form a polymeric article.
Separately, a 9 micron-thick polyester film ("Lumirror", Toray K. K.) was coated by application using an applicator with a 1 micron-thick fluorine-containing resin ("Fluorad FC-721", Sumitomo 3M K. K.) to obtain a surface reforming medium.
Then, the above-prepared polymeric article was covered with a negative mask in alignment and exposed for 0.1 sec under application of a thermal bias at 70° C. to fluorescent light having a peak at 380 nm from a fluorescent lamp 3 cm spaced apart, thereby to form a polymerization image.
Then, after removal of the negative film, the polymeric article was heated at 50° C. fine powdery silica ("Aerosil 200", Nihon Aerosil K. K.) was dispersed on the polymeric article, and the polymeric article was passed through rollers exerting a nip pressure for embedding a part or whole of the silica powder at the un-polymerized parts of the polymeric layer.
Then, the polymeric article was subjected to whole-area exposure under application of a thermal bias at 105° C. by using the fluorescent lamp used in the polymerization image formation to fix the powder silica in the polymeric layer, followed by removal of excessive silica, to obtain a printing plate according to the present invention.
The thus obtained lithographic plate was fixed about the plate cylinder of a desktop-type offset printer ("San-Offset" (trade name), mfd. by San Insatsu Kikai K. K.), and printing was performed on paper by using an oily ink ("Offset Ink New Rubber Black", Bunshodo K. K.) and dampening water (6-times dilution of an etch liquid available from Gestetner Ltd.), whereby sharp and good images were obtained.
A printing plate according to the present invention was prepared in the same manner as in Example 20 except that the polyvinyl butyral resin used for the polymeric article production was replaced by a polyvinyl butyral resin having a different polymerization degree ("Eslec BX-1", Sekisui Kagaku K. K.), the powdery silica was replaced by natural mineral powder ("Muki Smectone", Kunimine Kogyo K. K.), and a polytetrafluoroethylene film ("Teflon Tape TOMBO 9001", Nichiasu K. K.) was used as the surface reforming medium, and the exposure was performed through a negative mask disposed on the support of the polymeric article.
A printing plate according to the present invention was prepared in the same manner as in Example 20 except that the powdery silica was replaced by water-repellent polytetrafluoroethylene powder ("Lubron L-2", Daikin Kogyo K. K.) and the surface reforming medium was replaced by the one used in Example 10.
______________________________________Silver bromide           0.6    part(s)Silver behenate          5.0    part(s)Behenic acid             2.0    part(s)Phthalazinone            0.8    part(s)1,1'-Bis(2-hydroxy-3,5-dimethyl-                    2.5    part(s)phenyl)-3,3-dimethylpropane1-Carboxymethyl-5-[(3-ethyl-                    0.001  part(s)naphtho[1,2-d]oxazoline-2-indene)-dethylidene]-3-ethylthiohydantoinXylene/n-butanol (1/1)   90     part(s)Polyvinyl butyral resin  3.0    part(s)("Eslec BM-2", Sekisui Kagaku K.K.)Acrylic resin            3.0    part(s)("Dianal BR-77", Mitsubishi Rayon K.K.)Dipentaerythritol hexaacrylate                    3.0    part(s)("Kayarad DPHA", Nihon Kayaku)Benzyl dimethyl ketal    0.3    part(s)("Irgacure 651", Ciba-Geigy Corp.)______________________________________
Then, the surface reforming medium comprising a coating layer of a fluorine-containing resin on a polyester film used in Example 20 was superposed on the polymeric layer of the silver salt-containing polymeric article prepared above, and the superposed structure was passed through hot rollers at 50° C. to form a laminate.
Then, the laminate was subjected to imagewise exposure by using a drum scan-type laser beam printer (mfd. by Abe Sekkei K. K.) equipped with an He--Ne laser (output: 5 mW), then heated for 5 sec. at 125° C. to form a silver image at the exposed parts of the silver salt-containing polymeric layer, and then subjected to 20 sec of whole-area exposure on a hot plate at 70° C. to fluorescent light having a peak at 340 nm from a fluorescent lamp 3 cm spaced apart to polymerize the part of the silver salt-containing polymeric layer except for the parts with the silver image to obtain a polymerization image. Then, the surface reforming medium was peeled off.
______________________________________Photosensitive liquid (I)  1     part(s)Polyvinyl alcohol          1     part(s)("Gosenol NH-18", mfd. by Nihon GoseiKagaku K.K.)Pentaerythritol triacrylate                      1     part(s)("Kayacure DETX", mfd. by Nihon Kayaku K.K.)Trimethylolpropane triacrylate                      0.3   part(s)("Kayacure TMPTA", mfd. by Nihon Kayaku K.K.)2,4-Diethylthioxanethone   0.1   part(s)("Kayacure DETX", mfd. by Nihon Kayaku K.K.)Ethyl 4-dimethylaminobenzoate                      0.1   part(s)("Kayacure EPA", mfd. by Nihon Kayaku K.K.)Water/n-butanol            10    part(s)______________________________________
Onto the silver salt-containing polymeric article thus prepared, a negative mask similar to the one used in Example 20 was placed, followed by 1 sec. of imagewise exposure from a tungsten lamp 5 cm spaced apart, separation of the negative mask, and 4 min. of dipping of the polymeric article in a developing solution having the following composition at 40° C.:
______________________________________p-Methoxy phenol         12     part(s)Sodium sulfite           7      part(s)Sodium carbonate         5      part(s)Potassium bromide        0.1    part(s)β-acetylphenylhydrazine                    0.3    part(s)Water                    1000   part(s)(Sodium hydroxide for adjustment of pH 10)______________________________________
______________________________________Polyvinyl butyral resin   1      part(s)("Eslec BL-2", Sekisui Kagaku Kogyo K.K.)Trimethylolpropane triacrylate                     1      part(s)("Aronix M-309", Toa Gosei Kagaku K.K.)3,3'-Carbonylbis(7-dethylaminocoumarin)                     0.3    part(s)Ethyl 4-dethylaminobenzoate                     0.2    part(s)("Kayacure EPA", Nihon Kayaku K.K.)1-Nitroso-2-naphthol      0.001  part(s)n-Butanol                 13     part(s)______________________________________
A liquid having the above composition was applied by an applicator onto a 100 micron-thick polycarbonate film to form a polymerization layer in a dry thickness of 5-6 microns, on which the surface reforming medium used in Example 10 was laminated similarly as in Example 6.
______________________________________Silver bromide          2.0    part(s)Silver behenate         5.0    part(s)Behenic acid            2.3    part(s)Phthalazinone           2.0    part(s)2-Methyl-4-(3,5-dimethyl-4-                   2.31   part(s)hydroxybenzyl)naphtholPolyvinyl butyral resin 10.0   part(s)("Eslec BM-2, Sekisui Kagaku K.K.)Xylene/n-butanol (1/1)  100    part(s)______________________________________
Into the above liquid dispersion, 0.006 part of 3,3'-diethyl-2,2'-thiatricarbocyanine iodide and 1.0 part of N,N-diethylformamide were added and sufficiently dissolved and mixed. The resultant liquid was applied onto a 50 micron-thick polyester by an applicator to form a 5 micron-photosensitive silver salt layer, which was subjected to imagewise exposure by a semiconductor laser (780 nm, 10 mW) and to 10 sec. of thermal development at 100° C.
After the thermal development, the photosensitive silver salt layer was superposed onto the above-prepared surface reforming medium in lamination with the polymerization layer, and the superposed structure was placed on a hot plate heated at 85° C. and subjected to 20 sec. of polymerization exposure to fluorescent light having a peak at 420 nm from a fluorescent lamp 3 cm spaced apart from the polyester film. Thereafter, the surface reforming medium and the photosensitive silver salt layer peeled off from the polymerization layer, and the remaining polymerization layer was further subjected to 60 sec. of whole-area exposure by using the above fluorescent lamp and hot plate, thereby to obtain a printing plate according to the present invention.
A laminate of the polycarbonate film, the polymerization layer and the surface reforming medium was prepared by using the same materials and in the same manner as in Example 25. Further, a 5 micron-thick photosensitive silver salt layer of the same composition as in Example 26 was formed on the polycarbonate film, and further coated with a 2 micron-thick protective layer of polyvinyl alcohol ("Gosenol NH-17Q", Nihon Gosei Kagaku K. K.) by application with an applicator.
A 50 micron-thick polyester film was coated with a 10 wt. % solution in methyl ethyl ketone of the polyvinyl butyral resin used in Example 1 by an applicator to form a polyvinyl butyral resin layer in a thickness of 5-6 microns. The polyvinyl butyral resin layer showed a contact angle of 60 degrees.
Then, a 50 micron-thick polytetrafluoroethylene film identical to the one used in Example 1 was laminated onto the above polyvinyl butyral resin layer at a nip pressure of 0.2 kg/cm2 and a temperature of 80° C. Then, the resultant laminate was subjected to exposure under heating similarly as in Example 1.
1. A surface reforming method, comprising sequentially:
(i) a step of separately providing a surface reforming medium, and a silver salt-containing polymeric article supported on a support and comprising at least a polymerizable compound and a photosensitive silver salt compound,
(ii) a step of subjecting the silver salt-containing polymeric article to imagewise exposure to light,
(iii) a step of causing the surface reforming medium to contact the silver salt-containing polymeric article after the imagewise exposure,
(iv) a step of polymerizing the silver salt-containing polymeric article, and
(v) a step of peeling the surface reforming medium from the silver salt-containing polymeric article, so that a fraction of the surface reforming medium is materially transferred to the polymerized polymeric article.
2. A method according to claim 1, wherein after the step of separating the surface reforming medium, the silver salt-containing polymeric article is allowed to retain an un-polymerized part, to which powder is then attached.
3. A method according to claim 1, wherein said surface reforming medium comprises a resin selected from the group consisting of fluorine-containing resin, silicone resin, vinylidene chloride resin, and vinyl chloride resin.
4. A surface reforming method, comprising sequentially:
(i) a step of separately providing a surface reforming medium, and a photosensitive silver salt layer supported on a support and comprising at least a photosensitive silver salt component,
(ii) a step of subjecting the photosensitive silver salt layer to imagewise exposure to light,
(iii) a step of subjecting the photosensitive silver salt layer to thermal development,
(iv) a step of superposing a polymerization layer comprising at least a polymerizable compound on the photosensitive silver salt layer and superposing the surface reforming medium on the polymerization layer,
(v) a step of polymerizing the polymerization layer, and
(vi) a step of peeling the surface reforming medium from the polymerization layer so that a fraction of the surface reforming medium is materially transferred to the polymerized polymerization layer.
5. A method according to claim 4, wherein after the step of separating the surface reforming medium, the polymerization layer is allowed to retain an un-polymerized part, to which powder is then attached.
6. A method according to claim 4, wherein said surface reforming medium comprises a resin selected from the group consisting of fluorine-containing resin, silicone resin, vinylidene chloride resin, and vinyl chloride resin.
7. A process for producing a printing plate, comprising sequentially:
(iv) a step of superposing a polymerization layer comprising at least a polymerizable compound on the photosensitive silver salt layer and superposing a surface reforming medium on the polymerization layer,
(v) a step of locally selectively polymerizing the polymerization layer while leaving an unpolymerized part, and
(vi) a step of peeling the surface reforming medium from the polymerization layer so that a fraction of the surface reforming medium is materially transferred to the polymerized polymerization layer to provide the polymerization layer with a pattern of different wettability with water.
8. A process according to claim 7, wherein said surface reforming medium comprises a resin selected from the group consisting of fluorine-containing resin, and silicone resin.
US08157431 1990-08-03 1993-11-26 Surface reforming method, process for production of printing plate, printing plate and printing process Expired - Fee Related US5599648A (en)
JP2-206616 1990-08-03
JP2-316262 1990-11-20
JP2-316263 1990-11-20
US74063091 true 1991-08-05 1991-08-05
US08157431 US5599648A (en) 1990-08-03 1993-11-26 Surface reforming method, process for production of printing plate, printing plate and printing process
US74063091 Continuation 1991-08-05 1991-08-05
US5599648A true US5599648A (en) 1997-02-04
US08157431 Expired - Fee Related US5599648A (en) 1990-08-03 1993-11-26 Surface reforming method, process for production of printing plate, printing plate and printing process
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