GB2026709A - Process for Forming Relief Images by Transfer Development from Light-sensitive Material - Google Patents

Abstract

A relief image, e.g. for use as a printing plate, is formed by imagewise exposing a light-sensitive sheet material having a light-sensitive resin layer on a support, and the exposed layer is intimately contacted (e.g., by passage between pressure-applying rollers) with a carrier sheet (e.g., of paper or a polymer film) with a liquid promoter present (which may be coated on the light-sensitive layer or on the carrier sheet, prior to the contacting) which acts to selectively swell, plasticise or dissolve the exposed or unexposed areas of the layer or to reduce adhesion between the layer and its support; the carrier sheet is then separated from the sheet material, with portions of the light- sensitive layer, so as to leave a relief image on the support. The transferred portions on the carrier sheet can be used to check the quality of the image. Suitable types of the liquid promoter are organic solvents able to permeate the light-sensitive layer, surfactants, alkalis, acids and water.

Description

SPECIFICATION Process for Forming Relief Images by Transfer Development from Light-sensitive Material The present invention relates to an image-forming method, and more particularly it relates to a method for rapidly and easily forming relief images from a layer of light-sensitive resin composition without producing waste processing solution. In more detail, the present invention relates to a method of forming relief images by transfer development in the presence of a liquid transfer development promoter, e.g., a liquid which selectively dissolves or swells the exposed or unexposed areas of the light-sensitive layer. (Throughout this specification, the term "light-sensitive" includes materials which are sensitive to forms of radiation in general, including visible light).

A A conventional method for forming relief images using a light-sensitive image-forming material comprising a support having coated thereon a layer of a light-sensitive composition generally comprises imagewise exposing the image-forming material, dipping it into a developing solution which selectively dissolves or swells the unexposed or exposed areas whereby relief images consisting of the exposed or unexposed areas are obtained, removing the developing solution remaining on the support by washing and then drying. This process produces a large amount of waste processing solution because it requires large amounts of developing solution and washing water to process the relief images.

Studies directed to reducing the amount of processing solution which is required to develop such a material have been conducted both from the standpoint of the composition of the light-sensitive resin layer and the processing thereof in order to reduce the costs of processing and the environmental problems. The present invention relates to an image-forming method utilizing transfer development of a light-sensitive resin composition layer in a wet state.

In the silver halide photographic field various methods are known wherein a developing solution is spread on an exposed light-sensitive layer and components of the light-sensitive layer are selectively transferred to a receiving layer to form images on the receiving layer. For example, a silver salt diffusion transfer process for instant photography is disclosed in C. B. Neblette, Photography, Its Materials and Processes, 6th Edition, pp.368-391, published by D.Van Nostrand Co., Inc., New York (1962); a transfer method utilizing dyes or unreacted color couplers is disclosed in T. H. James, The Theory of the Photographic Process, 4th Edition, pp. 366-372, published by Macmillan Publishing Co., Inc., New York (1977); and a method for transferring a silver halide or dye to a receiving sheet by liquid is disclosed in C. B.Neblette, Photography, Its Materials and Processes, 6th Edition, pp. 435-445.

In addition, British Patent 740,165 discloses a method for forming color images by imagewise exposing a transfer material having thereon a water-soluble binder layer containing a pigment, e.g., carbon black, etc., which binder layer has been coated on a light-sensitive composition layer, contact bonding the transfer material to an image-receiving sheet while interposing water therebetween, and then subjecting a material to a peeling-off treatment to form the color images on the image-receiving sheet. This British Patent further teaches that an intaglio relief is obtained by using a support having an uneven surface as the transfer material.

These transfer image-forming methods are for obtaining images on a receiving sheet. According to these methods, components in the imagewise exposed light-sensitive composition layer which are essential for forming visible images are dissolved in a liquid developer and then transferred to the receiving sheet. However, the polymer binder which is used as the dispersing medium for the lightsensitive components is not transferred. For example, according to the silver salt diffusion transfer process, the silver halide in the unexposed areas of the light-sensitive layer is dissolved in the form of a soluble complex salt and is transferred to the receiving sheet containing a physical developing nucleus to form black silver images.According to another embodiment of the silver salt diffusion-transfer process, a developing agent, a dye precursor and a color coupler are transferred to the receiving sheet by development of an exposed light-sensitive material in sheet form to form visible images. In some case, images formed in the exposed light-sensitive material in sheet form are used instead of the transferred images.

The above explanation is an example of light-sensitive image-forming materials utilizing a silver halide emulsion as a light-sensitive substance because the silver halide emulsion has been known and researched in the field. Similar methods are known in the field of non-silver salt light-sensitive materials and their technical basis is substantially the same as that of the silver halide, i.e., essential components for forming visible images in the light-sensitive composition are transferred to the receiving sheet. These transfer image-forming methods are disclosed in Japanese Patent Application (OPI) No. 16439/74 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") and U.S. Patent 3,822,186.

A colloid transfer method is a known method for forming relief images by wet transfer development, as disclosed in U.S. Patents 2,596,756, 2,704,712 and 2,596,754. This image-forming method comprises imagewise exposing a light-sensitive image-forming material which comprises a support having coated thereon an unhardened gelatino silver halide emulsion layer, subjecting it to tanning development, and transferring a portion or all of unhardened areas of the light-sensitive imageforming layer to another sheet by the application of pressure. This method has been widely used for producing printing plates. Since this method essentially relies on tanning development and requires essentially transfer of unhardened areas to the receiving sheet, a complicated and highly developed technique is necessary for practicing the method.

As is apparent from the above explanation, relief images are formed prior to transfer. Thus, a liquid is used in the formation of images by: (i) transfer of only visible image-forming components of a light-sensitive composition layer, or (ii) transfer of unhardened areas of tanning developed gelatin or protein binder in the colloid transfer method.

On the other hand, several image-forming methods are known which comprise imagewise exposing an image-forming material comprising a support having coated thereon a light-sensitive composition layer, intimately contacting it with a receiving sheet and separating the two to selectively transfer exposed or unexposed areas of the composition layer to the receiving sheet. These methods are disclosed in U.S. patents 3,060,023, 3,060,024, 3,202,508, 3,525,615, 3,607,264, 3,736,138, 3,627,529 and 3,591,377, Japanese Patent Publication No. 9663/63 and Japanese Patent Applications (OPI) Nos. 94503/73, 141003/76 (DT-OS 2,524582)39025/76 (U.S. Patent 4,058,398), 126220/77, 57819/77 and 3215/78.These methods are dry methods utilizing a difference between the adhesion in the exposed and unexposed areas of the light-sensitive composition layer for the support and the receiving sheet.

A dry developing system is more desirable than a liquid system since it does not require a developing solution, and thus it is simpler and is not accompanied by a waste solution. However, the image quality obtained by this method, particularly the resolving power, is inferior to that obtained by liquid development For example, a lithographic printing plate produced by the method disclosed in our British Patent Application No. 47406/78 (a stripping development system) is capable of providing excellent resolving power and can provide dot reproduction of 175 lines/inch, but the fidelity of dot reproduction is inferior to that of a liquid-developed plate, as seen by examination of the dot formation under an electon microscope.

The present invention provides the advantages of a liquid developing system in image quality and the advantages of a dry processing system in simpler processing or no waste solution.

The invention thus provides an easy and pollution-free method for developing and fixing relief images.

According to the present invention, high quality relief images having excellent resolving power and image quality are obtained without any accompanying waste processing solution. Hence, the present invention is a useful method for making printing plates, light-sensitive materials for printing plates and photoresists for photofabrication of articles such as printed circuits.

According to the present invention, we provide a process of forming a relief image by transfer development to a flexible carrier sheet from the exposed or unexposed areas formed by imagewise exposing a light-sensitive sheet material comprising a layer of a light-sensitive resin composition on a support, which process comprises (a) intimately contacting the exposed layer of the material with the carrier sheet, with between said contacting sheets, a development promoter which is a liquid that selectively swells, plasticises or dissolves the exposed or unexposed areas of the light-sensitive layer or reduces adhesion between said layer and the support, and (b) separating the carrier sheet, with the transferred portions of said layer, from the light-sensitive material to form a relief image on said material.

Accordingly, there is no waste solution problem, the amounts of processing solution employed are low and high quality images are obtained because image-forming materials are processed by fresh processing solution. Thus, the present invention provides such advantages as no or reduced environmental pollution, low processing costs and high quality images.

The present invention represents an improvement on the invention disclosed in our Application No. 47406/78 which is a heat laminate stripping development process which comprises imagewise exposing a light-sensitive image-forming material, intimately contacting it with a carrier sheet for transfer development at room temperature or under heating, and separating the two to form images corresponding to the exposure pattern on the support.

In the present invention, a small amount of liquid transfer development promoter is provided or coated between the light-sensitive image-forming material and the carrier sheet to assist the transfer development. The transfer development promoter is a liquid that selectively swells, plasticizes or dissolves the exposed or unexposed areas of the light-sensitive resin composition layer, or reduces adhesion between the light-sensitive resin composition layer and the support.

In step (b) of the process, non-image portions (that is, portions which will not be used in printing) are transferred to the carrier sheet and can be used to indicate the quality of the printing plate or recording remaining on the support. These images on the carrier sheet may be of high quality having high edge gradient and high resolving power.

Each element employed in the present invention will be explained below in detail.

A support for the image-forming material used in the present invention may be any organic or inorganic material or a combination thereof taught for this purpose in the art as long as it has selfsupporting property and does not undergo dimensional change or soften during processing described below. Suitable examples of the support are polyester (e.g., polyethylene terephthalate, polycarbonate of bisphenol A), polyurethane, polyamide (e.g., a nylon), cellulose acetate, polyethylene, polypropylene, polyurea, epoxy resin, melamine resin and other thermoplastic or thermosetting polymer films and paper. Further, a metal layer, an organic material layer or an inorganic material layer can be provided on at least one surface of these sheet-like supports as a subbing layer for the light-sensitive resin composition.Suitable supports may also be prepared from sheets of metals or inorganic compounds.

Examples of suitable metals and inorganic compounds used for the subbing layer include aluminum, iron, chromium, zinc, tin, copper and other metal plates, glass, metal oxides (e.g., aluminum oxide, tin oxide or indium oxide or chalcogen compound. The inorganic compound may be used in the form of a foil, sheet, molded onto a plate, or laminated with another support material. The support employed in the present invention may be coated, vapored, laminated or treated.

As stated above, the support is desirably a sheet and may have a smooth or an irregular uneven surface, a curved surface. The thickness of the support employed in the invention is preferably about 10 ym to about 1 cm, but may vary somewhat outside of this range depending upon use. The support may be transparent or opaque or colored by dyes or pigments.

The light-sensitive resin composition layer used in the present invention contains as essential components a light-sensitive material which photochemically reacts upon exposure to actinic radiation and an organic polymeric binder. The composition may also contain additives for stabilizing the lightsensitive compound upon storage, coloring images and promoting development.

The light-sensitive resin composition used in the present invention can be selected from any of the many light-sensitive materials well known in the art. Some representative examples are illustrated below and in the accompanying examples.

A first group of suitable light-sensitive materials contains a photodecomposable compound such as a diazonium salt, an o-quinonediazide or an aromatic azide compound as disclosed in Kosar, Light Sensitive Systems, published by John Wiley and Sons Co., (1965), pp. 194-357, and W. S. De Forest, Photoresists, McGraw-Hill Book Company (1975).

A second type of light-sensitive composition is a free radical type composition containing a combination of a polyhalogen compound such as iodoform, carbon tetrabromide, a,a,a- tribromoacetophenone or tribromomethylphenylsulfone and a diphenylamine, a naphthol or a phenol.

Specific examples are disclosed in Takashi Yamamoto, Manual of Photographic Technique, first volume, published by Shashinkogyo Shuppansha (1977) pp. 192-204.

A third group is photosensitive compositions containing a quinone such as a phenanthraquinone, a naphthoquinone or a benzoquinone which are used in forming images by reducing a metal complex or a metal oxide upon heating. Examples of the metal complex are an organic tellurium compound or a cobalt complex as disclosed in Japanese Patent Application (OPI) No. 139722/75.

A fourth group includes photopolymers as disclosed in Manual of Photographic Technique, first volume, pp. 172-191, supra, or Takahiro Tsunoda, Light-Sensitive Resins, revised edition, published by Insatsu Gakkai Shuppanbu (1976). The typical examples of the photopolymers include photocrosslinkable compositions containing a diazonium salt or an aromatic bisamide compound as the photosensitive material, bichromate-colloid light-sensitive materials, and photopolymerizable or photocross-linkable compositions containing a polymer having a photoactive group (e.g., a vinyl group) in the main or a side chain and a carbonyl compound, a peroxide, a sulfur compound, a halogen compound or a compound having a vinyl group in which a photo redox system is used as an initiator. Vinyl cinnamate and polyvinyl cinnamylideacetate are included in this group.

As the binders for the light-sensitive resin composition layer, the film-forming polymers and the film-forming low molecular weight compounds conventionally used for this purpose can be used. Thus, a wide variety of materials may be selected from. The binders used in any specific application can be easily chosen based on their compatibility with the light-sensitive compound, the stability of the lightsensitive layer, and the adhesion properties of the support.

Typical examples of binder polymers are thermosetting linear polymers such as phenol resins, polyvinyl butyral, polyvinyl formal, polystyrene, polyacrylic acid, polymethyl methacrylate, poly(hydroxyalkyl acrylate), polyvinyl acetate, polyesters (e.g., polyethylene terephthalate), polyurethanes, polyamides (e.g., nylon-6, nylon-6,6, nylon-6,10), etc.; and thermoplastic polymers and copolymers such as vinylidene chloride/acrylonitrile, styrene/acrylonitrile, vinyl methyl ether/maleic anhydiide, vinyl acetate/maleic anhydride, vinyl chloride/vinyl acetate, vinyl chloride/styrene, and terpolymers containing a third or fourth monomer in addition to the copolymers described above.

Water-soluble polymers such as gelatin, polyvinyl alcohol or polyvinyl pyrrolidone, a partially crosslinked polymer and a non-thermoplastic polymers such as an epoxy resin can also be used as a binder.

These binder polymers are mixed with a thermoplastic resin to make the light-sensitive resin composition layer soften under heating.

Further, substances having poor film-forming property such as polyethylene glycol, resin, rosin, wax or fat may also be present with the binder as an additive to modify the film-forming property of the polymer binder.

The above polymers can be coated on the support as a latex by dispersing them in water or in an organic solvent. A liquid or viscous plasticizer at room temperature can be added to the light-sensitive resin composition as a modifier for the binder. An inorganic or organic powder or fine particle such as colloidal silica, starch, carbon black, glass powder or metal powder can also be added to the binder.

The light-sensitive resin composition layer may contain a dye, a pigment, a fine metal particle, a magnetic powder or a fluorescent substance in the form of a molecular dispersion, crystal or fine particle. In this regard, the relief images formed from the light-sensitive resin composition layer containing an electrically conductive fine metal particle or magnetic powder not only give visual information as a recording material but also are useful as a detecting means for dielectric constant or magnetic permeability.

The thickness of light-sensitive resin composition layer is generally about 0.5 ,um to 500 m and preferably about 1 ym to 100 ym.

In a conventional transfer or stripping development type light-sensitive image-forming material the adhesive strength between the light-sensitive layer and the support must be different from the adhesive strength between the light-sensitive layer and the carrier sheet in the exposed and unexposed areas for transfer or stripping development to be possible. According to the. present invention, by selecting a transfer development promoter for the light-sensitive material used, limitations on the lightsensitive resin compositions are removed and an image-forming material which can be transferdeveloped can be easily selected.

The carrier sheet for transfer development must be flexible and be able to intimately or closely contact the light-sensitive resin composition layer. Suitable materials for forming the carrier sheet include thermoplastic polymers and copolymers such as polyvinyl chloride, polyvinylidene chloride, polystyrene, polyethylene, polypropylene, polyamide, polyester, cellulose acetate, pqlyurethane or polyurea, paper, metal foil and cloth. These materials may be subjected to heat treatment or electrodischarge treatment, or may be over coated with a second component to modify the surface properties.

Materials having a laminate structure are particularly suitable as the carrier sheet in the invention.

Representative examples include paper laminated with polyethylene, polypropylene, vinyl chloride/vinylidene chloride copolymer; thermal laminates composed of a polyester laminated with a polymer having a low heat softening temperature: thermal adhesive films, etc.

In the method of the present invention, the carrier sheet is applied to the light-sensitive resin composition layer after imagewise exposure and hence the carrier sheet may be transparent or opaque.

In some cases, it may be colored or may include an inorganic or organic pigment or a solid particle. For example, a polyester film laminated with a cellulose triacetate film containing dispersed TiO2 is good carrier sheet for transfer development since it gives a white background and increases the surface activity.

The thickness of the carrier sheet is such that the exposed areas or unexposed areas of lightsensitive resin composition layer can be transferred without breakage of the carrier sheet at development. The thickness of the carrier sheet whether it be a single sheet or a laminated plastic film or paper is usually 10,um to 2 mm and preferably about 15 Mm to 0.5 mm.

The transfer development promoter is selected depending on the light-sensitive resin composition used. It is a liquid capable of selectively swelling, plasticizing or dissolving the exposed or unexposed areas of the light-sensitive layer, or reducing the adhesion between the light-sensitive layer and the support or subbing layer corresponding to imagewise exposure. The most effective promoter is a solution conventionally used as a developer in conventional image-forming process which is capable of selectively dissolving or swelling the light-sensitive resin composition or reducing the adhesion between the light-sensitive resin layer and the support. The promoter composition will vary with the components and use of the light-sensitive resin composition layer.Since the light-sensitive resin composition layer is composed of a polymeric binder and a light-sensitive material, the promoter must selectively dissolve or swell the exposed or unexposed areas of the light-sensitive element, and have an affinity for the polymer binder and assist in the transfer of the binder.

Generally, the transfer development promoter contains an alkali or an acid, an organic solvent and water, and if necessary, a surface active agent and a plasticizer. Suitable transfer development promoters which can be used in the present invention are those containing at least one of (1) an organic solvent having a high ability to permeate the light-sensitive layer such as aliphatic or aromatic alcohols (e.g., benzyl alcohol), xylene, glycols (e.g., ethylene glycol, propylene glycol), glycerol, lactones (e.g., y-butyrolactone), ethylene glycol monoethers (e.g., jB-methoxy ethanol, -ethoxy ethanol, p- butoxyl ethanol or p-ethoxy ethyl acetate), halogenated hydrocarbons (e.g., trichloroethylene or ethylene chloride); (2) surface active agents such as anionic surface active agents, cationic surface active agents, nonionic surface active agents (e.g., polyoxyethylene sorbitan esters), and ampholytic surface active agents; (3) organic or inorganic alkalis such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium silicate, sodium phosphate, potassium phosphate or a primary, secondary, tertiary or quaternary aliphatic amine; and (4) organic or inorganic acids such as hydrochloric acid, phosphoric acid, silicic acid or sulfuric acid, and an aliphatic or aromatic acid such as citric acid, acetic acid or oxalic acid. Furthermore, when the light-sensitive layer is developable with water, water can be used as the transfer development promoter.

The transfer development promoters may be used in the form of aqueous or non-aqueous solutions. In the case of transfer development promoters such as alcohols, these promoters may be used alone or in combination with other promoters, water or conventional solvents. Hence, transfer development promoters of the organic solvent type are generally used in concentrations of about 1 to 100% by weight. The surface active agent type promoters are used in solution in amounts of about 1 to 50% by weight and the alkali and acid type promoters are generally used to promote development at concentrations of about 0.1 to 10% by weight.

The transfer development promoter is selected for a particular light-sensitive resin compositlon layer in the same manner in which a developing solution is selected in conventional image-forming processes and, if transfer is carried out under heating, the developing ability of the promoter can be lower than that of a corresponding developing solution. A surface active agent functions as a promoter in that in accelerates wetting of the promoter against the light-sensitive material, swelling, partial dissolution, etc.

Suitable combinations of promoter and light-sensitive composition and the function of the promoter in exposed versus unexposed areas are shown in the following table. These examples, however, are not limiting and the skilled artisan can determine other combinations without undue experimentation.

Table Light-Sensitive Suitable Transfer Material Polymer Binder Use Development Promoters Function of Promoter Diazonium salt Copolymer Negative Alcohol, glycol, water Swells and dissolves Diazo resin containing presensitized and acid unexposed areas hydrophilic plate vinyl polymer o-Quinonediazide Novolak resin Positive (1) Sodium silicate and Dissolves exposed presensitized water areas plate Photoresist (2) Methyl, ethyl, butyl and phenyl cellosolve and glycol Aromatic azide Cyclized rubber Negative (1) Trichloroethylene and Swells and dissolves Novolak resin presensitized methyl ethyl ketone unexposed areas plate Photoresist (2) Alcoholic alkali solution Photo-cross-linking Same as left Photoresist (1) Methyl, ethyl, butyl Swells and dissoives initiator and column Chemical milling and phenyl cellosolve unexposed areas polyvinyl cinnamate and xylene Polycinnamylidene (2) Alcohol, surface derivative active agent and water Vinyl polymer and Organic polymer Photoresist Trichloroethylene and Swells and dissolves polymerization Megative methyl ethyl ketone unexposed areas initiator presensitized plate Polyhalide Vinyl polymer Presensitized Aqueous alkali solution Swells and dissolves Diphenylamine plate unexposed areas The temperature for transfer development is particularly important in the present invention.

Transfer development can be carried out at room temperature but is preferably carried out under heating. Less promoter is required and the processing speed is increased by practicing transfer under heating. These effects result because the polymer binder is swelled more which accelerates the developing speed and makes the transfer easier. The transfer development temperature used in a particular instance will vary depending on the image-forming material and the components of the promoter. Suitable temperatures range from about 1 OOC to 2500C, preferably from about 1 00C to 1 500 C, more preferably about 500C to 1 500 C. The pressure on the intimate contact between the light-sensitive layer and the carrier sheet is important.A suitable pressure between the pressure rolls is about 100 g to 5 kg, preferably 200 g to 1 kg, per 10 cm of rolls.

The transfer development time, i.e., the time the promoter and carrier sheet are in contact with the light-sensitive material, is not limited and, for example, the method of the present invention can be conducted by passing the carrier sheet and light-sensitive material assembly through pressure rolls at a speed of 5 meters per minute.

The present invention will be explained by referring to the accompanying drawings, in which: Figures 1 to 3 are cross-sectional views of light-sensitive image-forming materials processed in accordance with the present invention, and Figures 4 to 6 are diagrammatic cross-sections illustrating the development step in the process of the present invention.

Figure 1 shows a basic light-sensitive image-forming material consisting of a light-sensitive resin composition layer 12 coated on a support 11.

Figure 2 illustrates another embodiment of the light-sensitive image-forming material used in the present invention, in which a light-sensitive resin composition layer 12 is provided on a support 11 wherein a protective layer 13 is coated on light-sensitive layer 12.

Figure 3 illustrates still another light-sensitive image-forming material, in which a metal layer 14 is provided on the support 11 and the light-sensitive resin composition layer 12 is provided on the metal layer 14.

In Figure 4, an image-forming material comprising a support 11 having coated thereon a lightsensitive resin composition layer 12 has exposed areas 16 and unexposed areas 17. After imagewise exposure, the transfer development promoter 41 is coated on the light-sensitive resin composition layer and which is intimately contacted with a carrier sheet 21 for transfer development by means of a roller 31. After contact carrier sheet 21 and support 11 are separated whereby development is terminated and the exposed areas 1 6 of the light-sensitive resin composition layer 1 2 are transferred to the carrier sheet 21 and relief images are formed on the support corresponding to the unexposed areas 17 of the light-sensitive resin composition layer.

Figure 5 shows another development step using the same light-sensitive image-forming material as shown in Figure 4. The carrier sheet 22 is immersed in the transfer development promoter 42 prior to the transfer development. Development proceeds and image formation is the same as in Figure 4.

Figure 6 shows development of a negative type light-sensitive resin composition layer 13, in which the transfer development promoter 43 is supplied just before contacting the exposed lightsensitive resin composition layer (exposed areas 16 and unexposed areas 17) with the carrier sheet 25 which is a laminate of a first layer 23 and second layer 24 by means of a roll.

According to the method of the present invention, clear images can be formed on the carrier sheet in a negative-positive relation with the relief images formed on the support. On the other hand, when the promoter tends to bleed into the carrier sheet, clear images cannot be formed on the carrier sheet.

The present invention will be explained in more detail by the following examples. However, these examples and Figures 1 to 6 are provided for illustration only and are not intended to limit the present invention.

Example 1 A light-sensitive image-forming material was prepared by coating a positive-type light-sensitive resin composition comprising o-quinonediazide and novolak resin (trade name: AZ 1350 manufactured by Azoplate-Shipley Co.) in a dry thickness of 2 ssm on a film which contains a 0.2 m thick aluminum layer vaporized on 100 m thick polyethylene terephthalate film (trade name: Lumilar, manufactured by Toray Co.) and then dried. The light-sensitive resin composition layer and a resolving power chart were intimately contacted under vacuum and exposed to a 2 kw high pressure mercury lamp at a distance of 50 cm for 5 seconds. Further, the light-sensitive resin composition layer was contacted with a printing paper (70 g/m2) which had been immersed in the following transfer development promoter (a conventional developing solution for a light-sensitive resin composition layer) and then both sheets were passed through rollers heated at 400C and separated from one another. The aluminum layer with the exposed areas of the light-sensitive resin composition layer was etched and relief images corresponding to the unexposed areas of the light-sensitive resin composition layer having a resolving power of line width of 5 ym were obtained.

Promoter Composition NaOH 3.5 g NaBrO3 109 Na3PO4. 12 H20 0.5 g Water 11 Example 2 A light-sensitive image-forming material was prepared by coating a polyvinyl cinnamylidene type light-sensitive resin composition layer (trade name: KOR manufactured by Eastman Kodak Co.) in a dry thickness of about 5 ym on a 35 ym copper film laminated to a bakelite resin plate having a thickness of 0.2 mm by means of a spin coating machine and then drying.

The light-sensitive resin composition layer was intimately contacted with a printed circuit negative under vacuum and exposed to a 2-kw high pressure mercury lamp at a distance of 50 cm for 20 seconds. Further, the exposed light-sensitive layer was contacted with high quality printing paper (70 g/m2) in which trichloroethylene was immersed, and the two sheets were passed through rollers heated at 400C. The sheets were separated and positive resist images composed of the exposed areas of the light-sensitive layer were formed on the copper layer.The copper layer was dipped into a 40 wt% aqueous solution of ferric chloride heated to 400C for 1 minute to etch the copper layer corresponding to the unexposed areas of the light-sensitive layer, washed with water, dried, dipped in methyl ethyl ketone and rubbed with a brush to remove the resist images, whereby a good print circuit pattern was obtained.

Example 3 An aluminum plate mechanically sand-grained by the method disclosed in Japanese Patent Application (OPI) No.33911/73 (U.S. Patent Application Serial No. 284,851,filed August 30,1972) was dipped into a 2 wt% aqueous solution of sodium hydroxide heated to 400C for 1 minute to corrode a portion of the aluminum surface. After washing with water, it was immersed in a mixture of sulfuric acid and chromic acid for about 1 minute to expose the aluminum surface. The aluminum plate was then dipped in 20 wt% sulfuric acid heated to 300C, anodized for 2 minutes at a D.C. voltage of 1.5 volts and a current density of 3 A/dm2, washed with water and dried.

On the aluminum plate, a light-sensitive resin composition layer having the following components was coated in a dry thickness of 2 g/m2 by means of a roll coater.

Light-Sensitive Resin Composition Naphthoquinone-1 ,2-diazide(2)-5-sulfonic acid ester of acetone/pyrogallol prepared as in Example 1 of U.S. Patent 3,635,709 5 9 tert-Butylphenol/formaldehyde resin (trade name: PR-50530 manufactured by Sumitomo Durez Co., Ltd.) 0.5 g Cresol/formaidehyde resin (trade name: Hitanol 3110 manufactured by Hitachi Chemical Co.) 5g Methyl Ethyl Ketone 50 g Cyclohexanone 409 The layer was dried for 2 minutes at 100 C to obtain a light-sensitive image-forming material which had excellent properties as a presensitized plate after being stored in a dark place for 1 year.

The thus-obtained material was intimately contacted with a positive dot image having 175 lines/inch under vacuum and exposed to a 2 kw high pressure mercury lamp from a distance of 50 cm for 15 seconds.

The exposed light-sensitive layer was contacted with a high quality printing paper (70 g/m2) which had been immersed in the following transfer development promoter and passed through rollers heated to 500C. The contacting time of the high quality paper and the light-sensitive layer was about 10 seconds. Upon separation positive relief images were obtained corresponding to unexposed areas of the light-sensitive layer on the aluminum plate. The images were useful as printing images.

Transfer Development Promoter Sodium silicate 40g Sodium metasilicate 30 9 Water 30g Ethyl alcohol 30g The obtained printing plate was tested on a printing machine (trade name: Hamada 600). On the other hand, a printing plate for comparison prepared using large amounts of developing solution was also tested.

Both printing plates were of the same printing quality in first impression, ink-receptivity, scumming and dot reproduction, and of the same same printing durability.

Example 4 300 g of dioxane were heated to 1 000C in a nitrogen gas, and a mixture of 150 g of 2hydroxyethyl methacrylate, 60 g of acrylonitrile, 79.5 g of methyl methacrylate,10.5 g of methacrylic acid and 1.2 g of benzoyl peroxide was dropwise added over a period of 2 hours. After the completion of the addition, the reaction mixture was added to water to precipitate a polymer, and the polymer was dried at 700C under vacuum. The value of the thus-obtained 2-hydroxyethyl methacrylate copolymer (I) was 20. The viscosity of a 33% ethyleneglycol monomethyl ether solution of the copolymer at 250C was 4,500 cp.

An aluminum plate having a thickness of 0.15 mm was immersed in a 10% aqueous solution of sodium tertiary phosphate heated to 800C for 30 seconds to degrease, and grained by a nylon brush while sand powder was supplied to the aluminum plate. The aluminum plate was etched in sodium aluminate at 600C for 10 seconds and washed with a 3% aqueous solution of sodium bisulfate. The thus-processed aluminum plate was anodized in a 20% sulfuric acid at an electric current density of 2 A/dm2 for 2 minutes and treated with 2.5% aqueous solution of sodium silicate at 700C for 1 minute to obtain an anodized aluminum oxide plate.

On this aluminum plate, the following light-sensitive resin composition was coated and dried at 1 000C for 2 minutes.

Light-Sensitive Resin Composition 2-Hydroxyethylmethacrylate copolymer (lr 0.87 g 2-Methoxy-4-hydroxy-5-benzoylbenzene sulfonate of p diazodiphenylamine/p-formaldehyde condensate 0.1 g Oil blue 603 (C.1. No. 61555, manufactured by Orient Chemical Ind. Co.) 0.03 g 2-Methoxyethanol 6g Methanol 6g Ethylene dichloride 6g The dry coating amount of the composition was 2.1 g/m2.

The obtained light-sensitive material (presensitized lithographic printing plate) was contacted with an original having negative dot images of 1 75 lines/inch under vacuum, and exposed to a 2 kw high pressure mercury lamp for 1 5 seconds from a distance of 50 cm.

A transfer development promoter having the following composition was coated on the exposed light-sensitive layer in an amount of 40 ml/m2 and immediately the light-sensitive layer was contacted with a 30 ,um polyethylene layer laminated with Kurupakku paper and passed through rollers heated to 1 500C, and separated from the carrier sheet (polyethylene laminated with paper) whereby relief images corresponding to unexposed areas of the light-sensitive layer were formed on the aluminum plate.

Transfer Development Promoter Benzyl Alcohol 4g Sodium Dodecylbenzenesulfonate 4 g Triethanolamine ig Sodium Sulfite 0.3 g Water 90 g Propylene Glycol 50 g The thus-obtained printing plate was tested as in Example 3. The method of the invention provided the same printing quality in first impression, ink-receptivity, scumming and dot reproduction, and the same printing durability as conventional liquid developing methods.

Example 5 A sand grained aluminum plate was dipped in a 10% aqueous solution of sodium tertiary phosphate heated to 800C for 2 minutes, washed with water and desmutted with a 70% aqueous nitric acid solution.

The aluminum plate was dipped in a 20% aqueous sulfuric acid solution at 200C and anodized for 5 minutes under 12 volts D.C. and an electric current density of 2 Amp/dm2 (anode: aluminum plate, cathode: lead plate). After washing with water, the aluminum plate was dipped In 30% aqueous phosphoric acid at 500C for 3 minutes and washed with water. This plate was further treated with a 2% aqueous solution of sodium silicate heated to 800C for 1 minute, washed with water and dried.

On the aluminum plate, a light-sensitive resin composition having the following components was coated and dried.

Light-Sensitive Composition Light-sensitive polyester of an equimolar condensate of p-phenylene diacrylic acid ester/p-di(hydroxyethoxy)cyclohexane 10 9 1-Methyl-2-benzoylmethylene-,B-naphthothiazoline 0.8 g Phthalocyanine blue (C.l. No. 74,160) 29 Hydroquinone 0.2 9 Methylenedichloride 350g The light-sensitive image-forming material (presensitized printing plate) was contacted with a negative original under vacuum and exposed to a 2 kw high pressure mercury lamp for 15 seconds from a distance of 50 cm. 30 ml/m2 of a transfer development promoter having the following composition was coated on the light-sensitive layer and immediately the light-sensitive layer was contacted with a carrier sheet for transfer development which was composed of a 70 jum polyethylene terephthalate film laminated with 30 ym polypropylene and both were passed through rollers heated to 1 500C and separated from one another to form good relief images corresponding to the unexposed areas of the lightsensitive layer on the aluminum plate.

Transfer Development Promoter y-Butyrolactone 100 9 Water 59 Glycerol 10g Sodium Dodecylbenzenesulfonate 2 9 Ethylene Glycol 60g The printing plate was tested as in Example 3. The method of the invention provided the same printing quality in first impression, ink-receptivity, scumming and dot reproduction and the same printing durability as a conventional liquid developing method.

Example 6 The following transfer development promoter was prepared.

Promoter Composition Sodium Dodecylbenzenesulfonate 4 g Phosphoric Acid 0.5 g Water 35 g Benzyl Alcohol 49 Ethylene Glycol 0.5 g A printing plate was prepared in the same manner as in Example 4 except using a negative presensitized plate (trade name: GAN, manufactured by Fuji Photo Film Co., Ltd.) and using 30 ml/m2 of the above promoter. The test showed there was not a substantial difference in quality and property between the printing plate obtained by the method of the present invention and the printing plate (standard) obtained by liquid development.

Example 7 The same procedure as in Example 6 was repeated except that a Fuji Film negative type presensitized plate LAN (manufactured by Fuji Photo Film Co., Ltd; "Fuji" is a registered trade mark) was used. Printing tests showed the method of the present invention provided the same quality and property as the liquid developing method.

Example 8 A transfer development promoter was prepared as shown below: Transfer Development Promoter Benzyl Alcohol 2g Disodium Hydrogen Phosphate 2 9 Sodium p-Toluene Sulfonate 2 9 Sodium Silicate 10g Water 84g The same procedures as in Example 3 were repeated except that Fuji Film positive type presensitized plate SGP (manufactured by Fuji Photo Film Co., Ltd.) was used, a high quality printing paper (70 g/m2) was used as carrier sheet and the temperature of rollers was 50O C. Good positive relief images were formed on an aluminum plate. Printing tests confirmed that no printing problems occurred.

Example 9 The same procedures as in Example 8 were repeated except that a Fuji Film negative type presensitized plate SGN (manufactured by Fuji Photo Film Co., Ltd.) was used instead of the positive plate. The obtained printing plate was compared with the printing plate prepared by standard liquid development, and they provided the same printing qualities and properties.

Example 10 A degreased aluminum plate having a thickness of about 0.24 mm was grained with a nylon brush, and anodized by dipping it in a 20 wt% dilute sulfuric acid (300 C) under an electric current density of 3 A/dm2 for 2 minutes. The aluminum plate was washed with water, dipped in a 2% aqueous phosphoric acid solution, rewashed with water and dried. And the following light-sensitive resin composition was coated on the plate in a dry thickness of 2 ym.

Light-Sensitive Composition 20% Aqueous solution of polymethacrylic acid (viscosity 125,000 cps at 250C manufactured by Wako Junyaku, trade name: AC-30) 20 g Trimethylolpropane Triacrylate 5g Diheptyl Phthalate 1g N-Methyl-2-benzoylmethylene-p-naphthothiazole 0.2 g Butyl Alcohol 80g The composition layer was allowed to stand overnight at 500C to provide a light-sensitive lithographic printing plate. A pattern having a negative dot and line image was placed on the lightsensitive layer of the printing plate and the light-sensitive layer was exposed to 2 kw high pressure mercury lamp for 30 seconds from a distance of 50 cm.A high quality printing paper (70 g/m2) which had been immersed in water was contacted with the exposed light-sensitive layer and then passed through rollers heated to about 600C for about 1 minute, and separated from one another. Good positive relief images were fomred on the aluminum plate. Thus obtained printing plate was set on an offset printing machine and operated to obtain 20,000 printed sheets.

Example 11 Example 10 was repeated except that a light-sensitive resin composition having the following formula was used to obtain the same results as in Example 10.

Light-Sensitive Resin Composition 20% Aqueous solution of polymethacrylic acid (same as in Example 10) SO g Trimethylolpropane Tri methacrylate 59 Diheptyl Phthalate 2g Michler's Ketone 0.16g Benzanthrone 0.08 g Butyl Alcohol 80 g Example 12 On a copper plate for a printed circuit abraded in a conventional manner, the following lightsensitive resin composition was coated in a dry thickness of about 1 5 m.

Light-Sensitive Resin Composition 20% Aqueous solution of polymethacrylic acid (same as in Example 10) 20 g Trimethylolpropane Triacrylate 7g N-Methyl-2-benzoylmethylene--naphthothiazole 0.16 9 2,4,5,2',4',5'-Hexaphenyl-1,1 '-biimidazole (Lophine Dimer) 0.08 g Butyl Alcohol 80 g The light-sensitive layer was contacted with a negative printed circuit pattern, and exposed to a 2 kw high pressure mercury lamp for 1 minute from a distance of 50 cm. The light-sensitive layer was further contacted with a high quality printing paper which had been immersed sufficiently in water, and passed through rollers heated to about 700C for about 30 second s. The sheets were separated. A positive printed circuit pattern was formed on the copper plate corresponding to the exposed lightsensitive layer and the unexposed areas of the light-sensitive layer were removed and the copper surface corresponding thereto was exposed to air. The plate was etched by spraying it with a 40 wt% of aqueous ferric chloride solution (about 400C). The light-sensitive resin composition layer which was hardened by exposure acted as resist images until the etching of copper surface terminated. The plate was dipped in a 5 wt% aqueous sodium hydroxide solution (about 250C) to remove the resist images, washed with water and dried to obtain an excellent printed circuit pattern.

Example 13 The following light-sensitive resin composition was prepared.

Light-Sensitive Resin Composition Chlorinated Polyethylene (benzene solution, (71)=0.105 at 300 C, chlorination degree: 70 wt%) 50 g Trimethylolpropane Triacrylate 40 g 2-Methylanthraquinone 49 p-Methoxyphenol 0.2 g Microlith Red RT (manufactured by Ciba Ltd., pigment) 0.1 g Methyl Ethyl Ketone 300 ml The light-sensitive composition was coated on a sand-grained and anodized aluminum plate having a thickness of 0.24 mm by means of a whirler, and dried for 1 5 minutes at about 8O0C. The thickness of the dried light-sensitive layer was 2 ym. The light-sensitive layer was contacted with a negative letter under vacuum, and exposed to a 2 kw high pressure mercury lamp for 30 seconds from a distance of 30 cm.The exposed layer was further contacted with high quality printing paper (70 g/m2) which had been immersed in a mixture of methyl alcohol (2 volumes) and methyl ethyl ketone (1 volume) at a transfer development promoter. The two sheets passed through rollers heated to about 400C for 1 0 seconds and separated from one another. Positive relief images composed of the exposed areas of light-sensitive layer remained on the aluminum plate. Clear and oleophilic images of positive letters were obtained. The same operation as in Example 10 was repeated to carry out offset printing whereby good printed matter having clear letter images and no stained background were obtained.

Example 14 Example 13 was repeated except that 27 g of Aronix M-8060 (manufactured by Toa Gosei Kagaku Co.) and 13 g of Aronix M-6100 (manufactured by Toa Gosei Kagaku Co.). were employed instead of 40 g of trimethylolpropane triacrylate, and the same results were obtained.

Aronix M-8060 is a mixture of: 69.1% by weight of a polyester acrylate of the formula (obtained from the analysis):

which comprises tetrahydrophthalic acid, trimethylolpropane and acrylic acid, and 30.9% by weight of a compound of the formula

Aronix M-6100 is a reaction product having as a main component a compound of the formula:

prepared by reacting phthalic acid, diethylene glycol and acrylic acid in a molar ratio of 1:1:1.

Example 15 A light-sensitive resin composition was prepared as follows: Light-Sensitive Composition P;;Ty-P-Cinnamoylbxyethyl Methacrylate ((77)=0.14in methyl ethvl ketone solution at 250C) 29 Ester of acetone/pyrogallol condensate and 2-diazo-1-naphthol-5- sulfochloride (disclosed in Example 1 of U.S.Patent 3,635,709) 0.6 g Dioctyl Phthalate 0.6 g N-Methyl-2-benzolymethylene-ss-naphthothiazole 1 60 mg 1,2-Dichloroethane 24 g ss-methoxyethyl acetic acid 12 9 A light-sensitive lithographic printing plate was prepared by coating the composition on an aluminum plate as disclosed inExampIe 10, and drying the light-sensitive layer for 3 minutes at 800 C.

The thickness of the layer after drying was 2,us. The light-sensitive layer was contacted with a positive pattern having letter and dot images, exposed to a 2 kw high pressure mercury lamp for 15 seconds from a distance of 50 cm, contacted with a high quality printing paper (70 g/m2) which was immersed in the following transfer development promoter, passed through rollers heated to about 400C for 10 seconds, and then separated from one another. On the aluminum plate, positive relief images composed of the unexposed areas of light-sensitive layer remained.

Transfer Development Promoter Sodium Silicate (JIS 1; SiO2/Na2O=2.1 to 2.3; Six2=36 wt% to 38 wt%) 12 9 p-Butoxy ethanol 20 ml Benzyl Alcohol 20 ml Water 11 The surface on which the images were formed was exposed for 3 minutes under the condition of imagewise exposure to polymerize or harden the methacrylate in the light-sensitive layer. Offset printing was carried out using the plate as in Example 10, whereby excellent printed matter having clear letter and dot images without background stain was obtained.

Claims (1)

1. Claims

   1. A process of forming a relief image by transfer development to a flexible carrier sheet from the exposed or unexposed areas formed by imagewise exposing a light-sensitive sheet material comprising a layer of a light-sensitive resin composition on a support, which process comprises (a) intimately contacting the exposed layer of the material with the carrier sheet with, between said contacting sheets, a development promoter which is a liquid that selectively swells, plasticises or dissolves the exposed or unexposed areas of the light-sensitive layer or reduces adhesion between said layer and the support, and (b) separating the carrier sheet, with the transferred portions of said layer, from the lightsensitive material to form a relief image on said material.

   2. A method as claimed in Claim 1, wherein said light-sensitive resin composition layer is coated with said transfer development promoter prior to said contacting step.

   3. A method as claimed in Claim 1, wherein said carrier sheet is immersed in said transfer development promoter prior to said contacting step.

   4. A process as claimed in Claim 1,2 or 3, wherein said contacting is accomplished by passing said light-sensitive material in contact with said carrier sheet through pressure-applying rollers.

   5. A process as claimed in any preceding claim, wherein said transfer development is carried out at a temperature of 1 00C to 25O0C.

   6. A process as claimed in Claim 5, wherein said temperature is 500C to 1 500C.

   7. A process as claimed in any of Claims 1 to 6, wherein said development promoter comprises an organic solvent.

   8. A process as claimed in Claim 7, wherein said organic solvent is an aliphatic or aromatic alcohol, a glycol or glycerol.

   9. A process as claimed in Claim 7, wherein said organic solvent is a lactone.

   10. A process as claimed in Claim 7, wherein said organic solvent is an ethylene glycol monoether.

   11. A process as claimed in Claim 7, wherein said organic solvent is a halogenated hydrocarbon.

   12. A process as claimed in any of Claims 1 to 6, wherein said development promoter comprises a surface active agent.

   13. A process as claimed in any of Claims 1 to 6, wherein said development promoter comprises an alkali.

   14. A process as claimed in any of Claims 1 to 6, wherein said development promoter comprises a primary, a secondary, tertiary or quaternary organic amine.

   15. A process as claimed in any of Claims 1 to 6, wherein said development promoter comprises an acid.

   16. A process as claimed in Claim 15, wherein said acid is hydrochloric acid, phosphoric acid, silicic acid or sulfuric acid.

   18. A process as claimed in any preceding claim, wherein said carrier sheet is 10 4m to 2 millimetres thick.

   19. A process as claimed in any preceding claim, wherein said carrier sheet is a sheet of paper.

   20. A process as claimed in any of Claims 1 to 18, wherein said carrier sheet is a sheet of polyvinyl chloride, polyvinylidene chloride, polystyrene, polyethylene, polypropylene, polyamide, polyester, cellulose acetate, polyurethane, polyurea, metal foil, or cloth.

   21. A process as claimed in any of Claims 1 to 18, wherein said carrier sheet is a laminate of (a) a polyester film and (b) a cellulose triacetate film containing dispersed titanium dioxide.

   22. A process as claimed in any of Claims 1 to 18, wherein said carrier sheet is a laminate of (a) polyethylene, polypropylene or a copolymer of vinyl chloride and vinylidene chloride and (b) paper.

   23. A process as claimed in any of Claims 1 to 22, wherein said light-sensitive composition layer contains a diazonium salt, an o-quinone diazide or an aromatic azide compound.

   24. A process as claimed in any of Claims 1 to 22, wherein said light-sensitive composition contains a polyhalogen compound together with a diphenylamine, a naphthol or a phenol.

   25. A process as claimed in any of Claims 1 to 22, wherein said light-sensitive composition contains a phenanthraquinone, a naphthoquinone or a benzoquinone and a metal complex salt.

   26. A process as claimed in any of Claims 1 to 22, wherein said light-sensitive composition is a photo-cross-linkable composition.

   27. A process as claimed in any of Claims 1 to 22, wherein said light-sensitive composition is a photopolymerizable resin composition.

   28. A process as claimed in any preceding claim of forming a relief image, substantially as hereinbefore described with reference to Figures 4 and 5 or to Figure 6 of the accompanying drawings.

   29. A process as claimed in Claim 1 of forming a relief image, substantially as hereinbefore described with reference to any of the Examples.

   30. A relief image obtained by a process as claimed in any preceding claim.