GB1570967A

GB1570967A - Peel-apart type light-sensitive materials

Info

Publication number: GB1570967A
Application number: GB1542977A
Authority: GB
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1976-04-16
Filing date: 1977-04-13
Publication date: 1980-07-09
Also published as: DE2716759A1

Description

(54) PEEL-APART TYPE LIGHT-SENSITIVE MATERIALS (71) We, FUJI PHOTO FILM CO., LTD., a Japanese Company, of No. 210, Nakanuma, Minami/Ashigara-Shi, Kanagawa, Japan, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention is directed to peel-apart development type light-sensitive materials.

It is well known that images are formed by using light-sensitive materials and that such materials are utilized as masking materials, relief materials or printing materials. In most cases, the light-sensitive materials are imagewise exposed and then developed using a liquid developer. Where development is conducted with liquid treating agents, however, recently questions have arisen from a pollution standpoint on disposal of treating agents such as developers directlv as sewage or into rivers. On the other hand, various peel-apart development type light-sensitive materials capable of being treated in a dry manner which are developed by peel-apart development have now been proposed as a developing system which is free from liquid wastes. Such a system is described in, for instance, Japanese Patent Publication No. 9663/63, U.S. Patents Nos. 3.353,955 and 3,770,438 and Japanese Patent Application (OPI) No. 38521/75. These peel-apart development type light-sensitive materials all utilize the photopolymerizable property of light-sensitive monomers as a light-sensitive composition and the change in adhesion due to polymerization. In addition, examples of light-sensitive materials which are hardened by exposure to light are described in. for instance. U.S. Patents Nos. 3.591,377 and 3,672,672.

A peel-apart development type light-sensitive material is usually composed of a structure comprising, in sequence (a) a receptor sheet comprising a synthetic resin film, (b) a light-sensitive layer comprising an ethylenically unsaturated monomer, a polymer binder and a photopolymerization initiator and (c) and appropriate support, the receptor sheet and/or support being transparent. Such material is used as follows. Usually, an appropriate original is placed on a transparent receptor sheet. The light-sensitive layer is exposed to actinic radiation through the original and receptor sheet. Thereafter, the receptor sheet is peeled apart to transfer either of the exposed areas or the unexposed areas of the light-sensitive layer onto the receptor sheet; the other of these areas remains on the support. Thus, complementary images are formed on the receptor sheet and on the support.

For example, in Japanese Patent Publication No. 9663/63 and U.S. Patent Nos.

3,261,686, 3,353,955 and 3,770,438, the light-sensitive layer is a photoresist layer and the receptor sheet is laminated thereon and is a strippable transparent flexible film. This material is imagewise exposed through the flexible film; as a result, a difference in the adhesion to the support in comparison with the adhesion to the flexible film occurs both at the exposed areas and at the unexposed areas of the photoresist layer, respectively, so that when the flexible film is peeled-apart the photoresist layer is separated in a condition where either of the exposed areas or the unexposed areas adhere to the support and the other of these areas adheres to the flexible film, to thereby obtain on the support the desired resist image; thereafter, the material is treated with an organic solvent which dissolves the surface of the base plate where it is not protected by the resist image; the portions which are coated with the resist layer remain undissolved on the surface of the base plate to form images.

This type of image formation has been applied to the preparation of a lithographic printing plate using a base plate such as surface-treated aluminum or to the preparation of a printed circuit plate for an electric circuit using a system comprising an electrically insulating material having thereon a metal layer.

In such a type of light-sensitive material, the flexible film has been hithertofore laminated on the light-sensitive layer with the film being the same'size as the light-sensitive layer. In such a structure, it has been extremely difficult to peel-apart the flexible film as the hardness of the light-sensitive layer increased.

In addition, complicated procedures, particularly with automatic development, are encountered on peeling-apart of the receptor sheet. A method of using an adhesive tape has been proposed as a means for peeling apart of the receptor sheet. For example, a method is known which comprises adhering a continuous adhesive web to a receptor sheet of the exposed material and continuously winding up the web, as described in U.S. Patent No.

3,794,546. Further, as described in W. German Patent Application OLS No. 2,634,413, a method has been proposed of peeling apart the receptor sheet using a tape adhered to one edge of the light-sensitive material, where a part of the tape so adhered protrudes from the edge of the light-sensitive material sheet. However, this peeling-apart method using such a tape involves the disadvantages that the adhesive tape should always be ready for use and development processing is costly since tapes are consumed each time upon development.

The present invention obviates the above-described disadvantages of conventional light-sensitive materials. Accordingly, the present invention provides a method of producing an image which comprises (1) imagewise exposing a light-sensitive material comprising, in order (a) a flexible film, (b) a light-sensitive layer comprising a light-sensitive composition, and (c) a support, in which either one of said flexible film or said support is capable of transmitting actinic radiation to which said light-sensitive layer is sensitive and the adhesion of said light-sensitive layer to the film or the support is altered upon irradiation by said actinic radiation so that, after imagewise exposure, the light-sensitive layer is separated in a condition where one of the exposed areas or the unexposed areas is adhered to the support and the other is adhered to the film when the material is peeled apart, (2) peeling-apart the film to form the image on the support, and (3) before the imagewise exposure providing the light-sensitive material with a means facilitating peeling-apart of the flexible film from the remainder of the material before said peeling apart.

The light-sensitive material in accordance with the present invention provides the advantages of using developing machines with a simple mechanism and of obviating pollution problems.

The terms "peel-apart development type" and "peeling apart" are also often respectively referred to as "delamination development type" and "delamination" and are used herein interchangeably.

In the accompanying drawings: Figure 1, Figure 2 and Figure 3 are perspective views of peel-apart development type light-sensitive materials having protruding delamination edges.

Figure 4 and Figure 5 are perspective views of peel-apart development type light-sensitive materials where delamination edges do not protrude.

Figure 6 and Figure 7 are perspective views of peel-apart development type light-sensitive materials in the shape of a roll.

Figure 8 is a perspective view of a peel-apart development type of light-sensitive material where portions of the support are cut away.

Figures 9 to 11 are plan views of peel-apart development type light-sensitive materials having delamination edges which may or may not contain print-out images.

Figure 12(a) is a perspective view of an even further embodiment of this invention with Figure 12(b) being a cross-sectional view along line A-A' of the embodiment shown in Figure 12(a).

Figure 13(a) is a perspective view of a still further embodiment of this invention with Figure 13(b) being a cross-sectional view along line A-A' of the embodiment shown in Figure 13(a).

In Figures 1 to 13, 1 is a delamination edge, 2 is a flexible film, 3 is a light-sensitive layer, 4 is a support, 5 is a cut away portion, 6 is a print-out image, 11 is a support for an adhesion tape, 12 is an adhesive layer and 13 is a paper or plastics film.

In Figures 12 and 13, 2 is a flexible film, 3 is a light-sensitive layer, 4 is a support, 11 is a support of an adhesion tape forming a delamination edge, 12 is a layer of an adhesive composition partially (Figure 12) or completely (Figure 13) covering one surface of support 11 and 13 is a cover of, e.g., a paper or synthetic resin film covering an area of the adhesive composition 12 not in contact with the flexible film 2.

We refer now to the drawings.

As shown in Figures 1 to 3, flexible film 2 has an edge portion 1 which protrudes from the material so that it extends beyond the light-sensitive layer 3 on the support 4. Accordingly, when the flexible film 2 is peeled apart by holding the protruding portion 1 after imagewise exposure from the side of the support 4 or from the side of the flexible film 2, peeling apart can be extremely easily accomplished. In other words, the light sensitive material in accordance with the present invention enables the flexible film to be peeled apart easily from a laminate for peel-apart type development.

The protruding portion 1 of the flexible film may be provided only at the one end, as shown m Figure 1. However, in a very large piece of light -sensitive material, the protruding portion may be provided at many locations or around all of the edges.

The size and shape of the protruded portion 1 can be varied depending upon the peel-apart means used such as peeling apart mechanically or manually, but in any case, it is sufficient if the protruding portion can be held with the means used for peeling apart.

The present invention also includes the following embodiment. That is, the peel-apart development type light-sensitive material is a laminate comprising a protective layer 2 (flexible film), a transparent flexible support 4 and a light-sensitive layer 3 present therebetween, the protective layer and transparent flexible support protruding from the light-sensitive material. In forming images on a base plate using the laminate, the protruding portion of the protective layer is initially held and peeled apart from the laminate; the exposed surface of the light-sensitive layer is superimposed on the base plate on which images are to be formed and is adhered thereto under pressure; after imagewise exposure through the transparent flexible support, the protruding portion of the support is held and peeled apart to facilitate development; thus the desired images are formed on the base plate. In this case, a laminate comprising a base plate, a light sensitive layer and a flexible support having a protruding portion is also included within the present invention.

Depending upon the peeling apart'development type light-sensitive material, as shown in Figure 2 a type is used in which the entire area of the light-sensitive material (three-layered laminate) sheet is not utilized for image recording but one end alone remains blank. In such a case. it is possible for the blank end to be utilized for peel-apart development either by maintaining the light sensitive layer and the receptor sheet or the light sensitive layer and the support in a previously peeled apart state, or by maintaining a small resistance to peeling apart and therefore in a condition to be easily peeled apart. By doing so, the disadvantage of using adhesive tapes as articles which are consumed can be eliminated.

For simplicity of explanation hereinafter, the portion which is previously peeled apart or whose resistance to peeling apart is small and is utilized as a holding means upon peel-apart development is simply referred to as an "edge facilitating peeling apart or delamination".

The term "edge facilitating peeling apart" or "edge facilitating delamination" is used herein for the purpose of describing that portion of the light sensitive material which can be utilized as a means for peeling apart development, but no limitations are to be construed to exist relative to its shape and size. Hereinafter such will be simply referred to as a '*delamination edge" or "peeling apart edge".

The shape of the delamination edge(s) can be varied depending upon the features of peel-apart development. For example, where peel-apart development is manually performed and the sheet to be peeled apart is sufficiently strong, it is sufficient for the delamination edge(s) to be large enough to be held between the fingertips (e.g., as shown in Figure 4 and Figure 8). However, where development is to be performed with an automatic peeling apart machine without using any auxiliary means such as adhesive tapes or adhesives, it is desired for the delamination edge(s) to be a narrow strip and have a width above about 5 mm (e.g., as shown in Figure 5).

There are various methods for providing the above-described delamination edge(s).

For example, where a light-sensitive solution is coated on a continuous support followed by drying to form a light-sensitive layer, a peel-apart sheet is laminated thereon and thereafter the laminate is cut into sheets of a suitable size, uncoated areas are previously formed at both edges of the support by adjusting the width to correspond to that of the portion to be peeled apart and a peel-apart sheet is laminated thereon over the entire width of the support; thereafter by cutting, a light-sensitive sheet having delamination edge(s) at both edges or at one edge can be prepared (e.g., as shown in Figure 6). Alternatively, the delamination edge(s) can also be formed by a method comprising coating a light-sensitive layer on a continuous support, drying the coated layer and then coating a releasing agent (such as a silicone resin, polyvinyl alcohol, a paraffin, a wax or a polytetrafluoroethylene dispersion.) at both border portions (or at one border portion), or by a method of adhering releasing sheets on the support at spaced intervals in the coating direction and then cutting the same (e.g., as shown in Figure 7).

The methods described above are all methods for producing light-sensitive materials in which a part of the peel-apart sheet is previously peeled apart from the support or the light sensitive layer. Further alternatively, it is also possible to form the delamination edges as shown in Figure 8 by previously providing holes 5 piercing a strip of the support at definite intervals, laminating a peel-apart sheet with a light-sensitive layer previously provided thereon onto the support and then cutting the laminate along a line connecting the center of the holes, so as to provide a piece of light-sensitive material of a size ready for use.

On the other hand, a method of providing the delamination edge(s) can be used in which the degree of adhesion either between the peel-apart sheet and the light sensitive layer or between the light-sensitive layer and the support, is decreased at the ends to be peeled apart, using any means. In most cases, this method is simpler and more useful in actual production than the method of providing delamination edge(s) which are previously peeled apart. As a method of providing such a delamination edge, there is a method which comprises causing a change such as a hardening or a decomposition to occur in the light-sensitive layer prior to imagewise exposure, by radiation or by heat to thereby weaken the degree of adhesion. In general, if a chemical change in the light-sensitive layer is achieved by irradiation with actinic radiation, for example, from the transparent support side, a difference in adhesion occurs between the light-sensitive layer and the peel-apart sheet or between the light-sensitive layer and the support, at the irradiated areas and the non-irradiated areas with the actinic radiation. For example, if actinic radiation is irradiated from the transparent peel-apart sheet side, the light-sensitive layer is hardened, whereby the adhesion between the light-sensitive layer and the peel-apart sheet is markedly decreased. In such a case, the desired delamination edge(s) can be provided by irradiating with actinic light only of the portions, necessary for peel-apart development, of the peel-apart development type light-sensitive material sheet.

On the other hand, where the light-sensitive layer is changed by thermal means, for example, it is possible to markedly reduce the degree of adhesion between the light-sensitive layer and the peel-apart sheet by hardening the light-sensitive layer at the portion corresponding to the delamination edge by previously heating the portion necessary for peel-apart development. In this case, the desired delamination edge can be provided in accordance with this method.

Further. as another embodiment for providing the delamination edge, as shown in Figures 12 and 13 it is possible to provide the delamination edge by stick-adhering a material comprising a tape-shaped flexible support 11 having a layer 12 of an adhesive composition on one surface thereof (hereafter referred to as an adhesion tape) either over the entire length of the edge continuously along the edge of a peel-apart sheet 2 (flexible film of a peel-apart development type light-sensitive element, or to a part of the edge as shown in Figures 12 and 13. In this case, it is not only possible to provide the layer of the adhesive composition of'the adhesion tape only at the portion adhering to the peel-apart sheet. but also possible to provide such over the entire surface of one side of the adhesion tape, the remaining part thereof other than that adhering to the peel-apart sheet being covered with a paper tape or a flexible plastic tape 13 as shown in Figure 13. In addition, it is also possible to use an adhesion tape having a layer of an adhesive composition over the entire surface of one side of the adhesion tape and, simultaneously or, before or after stick-adhering a part of the adhesion tape to the peel-apart sheet, to stick a paper tape or a flexible plastic film tape to the portion of the layer of the adhesive composition of the adhesion tape not contacting the peel-apart sheet. In this case, it is preferred that pressure-sensitive adhesive compositions be used as the adhesive composition. Commer cially available pressure-sensitive adhesion tapes can be employed as the adhesion tape. In addition, adhesion tapes prepared so as to have a shape and width suitable for use as a delamination edge of the peel-apart development type light-sensitive element having the delamination edge in accordance with the present invention can be used. Paper, synthetic paper, composite materials of flexible organic high molecular weight materials and paper, and flexible organic high molecular weight material films can be employed as flexible supports for the adhesion tape.

It is also possible to practice the above described methods by placing a part including the edge of a material comprising a tape-shaped flexible support having a layer of a heat-sensitive adhesive composition (hereafter referred to as heat-sensitive adhesion tape) so as to overlap the edge of the peel-apart sheet of the peel-apart development type light-sensitive element and by heating the overlapping portion to adhere the tape thereto.

In this case, the layer of the heat-sensitive adhesive composition of the heat-sensitive adhesion tape (a portion of which does not overlap the peel-apart sheet) does not exhibit an adhesive property or a sticking property at ordinary temperatures (from 10 to 400C) and therefore this is advantageous.

It is further possible to provide the delamination edge by using an adhesion tape together with the method of reducing adhesion between the light-sensitive composition layer and the peel-apart sheet by means of a thermal method or a method of irradiating with actinic radiation. The above-described method of providing the delamination edge using an adhesion tape is extremely advantageous from an industrial viewpoint since the delamination edge can be provided continuously or independently for each sheet of the light-sensitive element cut in a sheet shape at any time after the preparation of the peel-apart development type light-sensitive element.

The following characteristics can be imparted to the delamination edge(s) prepared in accordance with the various methods as described above. That is, the delamination edge(s) can be clearly shown by a method generally called "print-out" in lithographic printing plates in which an image is obtained simply by imagewise exposure. In particular, where the delamination edge is not peeled apart and moreover the delamination edge is provided only at the one end, this "print out" method can be particularly effectively used. In addition, if the "print out" method is utilized, it is possible to print indicia in area 6 such as tradename, date of manufacture, manufacturing lot, etc. to thereby provide information thereon for users. Such an example is shown in Figure 9. A specific method for providing such a previously exposed delamination edge is by laminating a negative film having the desired images only on the portion of the delamination edge and printing out with actinic radiation after covering the other portions suitably with a black sheet. In addition, as a method for providing print out images only at the delamination edge, a method which comprises feeding a sheet-shaped light sensitive material into an exposure device equipped with a pressing plate having through holes in a shape of patterns or letters to be printed out at the delamination edge and with a snpport plate which does not have any through holes, and exposing the light-sensitive material with actinic radiation by holding it between the pressing plate and the support plate, thus enabling the desired patterns or letters to be printed out at the delamination edge. In this case, of course, the exposure can also be made so as to expose the entire portion of the delamination edge except for the necessary patterns or letters which are shielded from the actinic radiation (e.g. as shown in Figure 9, Figure 10 and Figure 11). The peel-apart development type light-sensitive material in accordance with the present invention comprises a laminate comprising (a) a flexible film, (b) a light sensitive layer comprising a light sensitive composition and (c) a support which are laminated in the sequence of (a), (b) and (c). Imagewise exposure is made from a transparent side of either one of (a) or (c). By peeling (a) and (c) from each other, images can be developed.

Suitable light sources for imagewise exposure which can be used are light sources providing electromagnetic radiation which is transmitted through the transparent film or support and can cause changes such as photohardening in the light sensitive layer to occur, for example, light sources emitting ultraviolet-visible light in the wavelength range of about 290 to about 700 my, preferably about 350 to about 500 m. Preferred examples of suitable light sources include a high pressure mercury lamp, a xenon lamp, a carbon arc lamp, a halogen lamp, and a laser. In addition, exposure can be made by using electron beams or X-rays.

A flexible film having a thickness of about 4 to about 150 Il, preferably about 10 to about 50 , is generally employed, but the thickness is not necessarily limited to this range. The film is usually a synthetic resin film such as a polyester film (e.g. a polyethylene terephthalate film), a polyolefin film (e.g. a polyethylene film, or a polypropylene film), but if desired, may be a sheet comprising fiber-like materials, e.g., a melamine resin or a urea resin emulsion, or may be a paper sheet which is sized with a synthetic rubber emulsion. In addition, a composite material comprising two or more kinds of films or sheets can also be employed.

With regard to the flexible cover film for peeling apart used in this invention, such must have a smooth surface and if necessary good light-transparency. For example, various synthetic resin films such as polyethylene terephthalate, polypropylene, polyethylene, cellulose triacetate, cellulose diacetate, polyvinyl chloride, polyvinyl alcohols, polystyrene, regenerated cellulose sheeting, polyvinylidene chloride, polytetrafluoroethylene, polytrifluoroethylene and like films can be used.

The light-sensitive layer comprises most generally a monomer which is polymerized by a radical chain addition-polymerization, and more specifically, it comprises (1) an ethylenically unsaturated monomer, (2) a high molecular weight binder, (3) a photopolymerization initiator and (4) other additives such as stabilizing agents, plasticizers and fillers. Specific examples of suitable ethylenically unsaturated monomers include acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl esters, vinyl ethers, vinyl esters. N-vinyl compounds, styrenes and crotonic acid esters. These materials are described in detail in U.S. Patent No. 3,770,438 and Japanese Patent Application (OPI) No.

38521/75, In addition, recently peel-apart development type light-sensitive materials using certain kinds of diazonium compounds, e.g., bis [4-(4-tolylthio)-2,5-diethoxybenzene- diazonium chlorides zinc chloride addition product, instead of the ethylenically unsaturated monomer, have been used. Further, a photohardenable material comprising a polyene containing two unsaturated carbon-carbon bonds at least in the same molecule and containing two or more thiol groups in the same molecule is disclosed in U.S. Patent 3,726,676 as a material which is hardened by the action of light.

The light-sensitive composition composed as above is usually dissolved in an organic solvent. The resulting solution is coated on a support and dried to provide a light-sensitive layer.

Various support materials can be used as the support of the present invention, depending upon the purpose of use. Specific examples include synethic resin films such as those of polyethylene terephthalate, polypropylene, polystyrene, cellulose triacetate, cellulose diacetate, polyvinyl chloride, polycarbonate, polyamide or polyimide film, paper, wood, metal plates such as aluminum plates, surface treated (e.g., grained anodically oxidized and/or phosphate-treated) aluminum plates, zinc plates, chromium-iron laminated plates, chromium-copper-iron laminated plate, metal foils and glass plates. In addition, surfacetreated metal plates and synthetic resin films on whch a metal thin layer has been provided by vapor deposition, plating or the like can also be employed as a support.

As stated above in detail, any peel-apart type developing machine which is employed in the prior art can be utilized to develop of the peel-apart development type light-sensitive material having a delamination edge at least at the one end thereof.

That is, the method as disclosed in the aforesaid W. German Patent Application OLS No. 2,634,413 is also convenient for developing the light-sensitive material in accordance with the present invention.

With some embodiments of the light-sensitive material in accordance with the present invention of course, the adhesion of tapes, which has previously been required at some point in time prior to peeling apart is no longer necessary. The delamination edge which is provided by a protrusion at least atone end thereof can be utilized in place of the tapes.

That is, if the light sensitive material sheet having a protruding delamination edge, or, even where no protruding delamination edge is present, if the light sensitive material, is passed so as to press the delamination edge onto a suction roller, the suction roller ensures complete holding of the peel-apart sheet at the delamination edge thereof and completely press holds the peel-apart sheet between a pair of rollers which makes a pair with the suction roller, thus peel-apart development can be assured.

In accordance with the present invention, the flexible film per se can be held upon peeling apart the flexible film from the peeling part type light sensitive material. Therefore, the operation of peeling apart can be readily and easily achieved with good reliability, which results in an extremely simple mechanism for developing machines used for peeling apart applicable to the light sensitive material in accordance with the present invention.

The present invention is explained in more detail with reference to the examples hereinbelow, but the present invention is not be be construed as being limited thereto.

Example I An aluminum plate (thickness of 0.3 mm) which was subjected to graining by a mechanical means was immersed for 1 min in a 2 wt% aqueous sodium hydroxide solution which was kept at 40"C, to thereby partly etch the surface thereof. After washing with water, the plate was immersed in an aqueous solution of a mixture of 2 wt% sulfuric acid and 1 wt% chromic acid at 40"C for about 1 min to expose pure aluminum surface. Then, the plate was immersed in a 20% aqueous sulfuric acid solution which was kept at 300C and was subjected to anodic oxidation for 2 min under the conditions of a direct current voltage of 15 V and a current density of 3 A/dm2. After washing the

Chlorinated Polyethylene (Cl content: 60 wt%; Sp.G: 1.20; Mooney viscosity (MS 4', 100"C): 80, made by Showa Denko Co.. Ltd. under the tradename of "Elaslen-401 A") 15 g Diglycerin Trimethacrylate 25 g 1 -Methyl-2-benzoylmethylene ss-naphthothiazine 0.3 g p-Methoxyphenol 0.2 g Copper Phthalocyanine Pigment (Cl 74160) 0.1 g Ethylene Chloride 80 g The light-sensitive layer was dried to remove the solvent. The light-sensitive layer on the thus obtained aluminum plate had a thickness of 4 ,u. A polyethylene terephthalate film having a thickness of 16 ij was further superimposed on the light-sensitive layer under pressure.

The thus superimposed sheet for a lithographic printing plate of a size of 60 cm long and 40 cm wide was left uncovered at a distance of 1 cm each from the opposite edges thereof, respectively, with the remaining portions being covered with a black paper sheet. The plate was then exposed to light for 20 seconds from a distance of 40 cm using an ultra-high pressure mercury lamp of 2 kW. The thus exposed opposite strippable edges each having a width of 1 cm were easily delaminated in an automatic peel-apart-developing machine using only a light pressing on a sponge roll rotating in a reverse direction to the running direction of the aluminum plate.

After a negative image original was closely contacted onto the polyester film of the printing plate in which one edge was delaminated, the printing plate was imagewise exposed to light for 15 seconds from a distance of 40 cm using an ultra-high pressure mercury lamp of 2 kW. The exposed printing plate was peel-apart developed by inserting it into an automatic peel-apart developing machine. Thus, positive printing images were formed on the aluminum plate.

For comparison, a lithographic printing plate having no exposed areas at the edges thereof was lightly pressed on the above discribed sponge roll, but the edge portions were not delaminated. Therefore, peel-apart development was not effected even when the printing plate was inserted into the above-described automatic peel-apart developing machine.

Example 2 An aluminum plate (thickness of 0.24 mm) which was subjected to graining by a mechanical means was immersed for 1 min in a 2 wt% aqueous sodium hydroxide solution which was kept at 40cC, to thereby partly etch the surface thereof. After washing the plate with water, the plate was further immersed in an aqueous solution of a mixture of sulfuric acid and chromic acid for about 1 min to uncover a pure aluminum surface. The aluminum plate for lithography, the surface of which had been cleaned by the procedures described above, was subjected to an anodic oxidation treatment on a surface thereof in a 20% aqueous sulfuric acid solution at 30"C as described in Example 1. After washing the plate with water, the aluminum plate was immersed in a 2% aqueous solution of JIS No. 3 sodium silicate for 2 mins at 50"C. After washing the plate with water sufficiently, the aluminum plate was dried.

Then, a solution of the following light-sensitive composition was coated on one surface of the aluminum plate: Chlorinated Polyethylene (Cl content: not less than 66 wt%; viscosity: about 300 cps in 40 wt% toluene solution at 25 made by Sanyo Kokusaku Pulp Co., Ltd. under the tradename "Superchlon HA") 15 g Trimethylolpropane Trimethacrylate 20 g 2-Ethylanthraquinone 0.6 g p-Methoxyphenol 0.2 g Copper Phthalocyanine Pigment (CI 74160) 0.1 g Toluene 70 g The coated amount was such that a dry thickness of 4 ,u was obtained. A polyethylene terephthalate film having a thickness of 16 11 was further superimposed under pressure on the aluminum lithographic printing plate on which the light sensitive layer had been coated.

When the thus obtained peel-apart developing type lithographic printing plate was cut-finished to a definite size, one edge of the support of the aluminum plate was cut in a shape as shown in Figure 8 to provide a delamination edge. After imagewise exposure, the polyethylene terephthalate film was'faced down. While feeding the lithographic printing plate horizontally, peel-apart zones which were formed by previously cut-finishing the aluminum plate were folded backwards by manually seizing the peel-apart zones so that peel-apart developing was smoothly facilitated. In this case, when the polyethylene terephthalate back surface of the printing plate had been exposed to light prior to development over the entire width of the printing plate at the area corresponding to the portions previously cut-finished, the peel-apart developing operation becomes easier.

Example 3 An aluminum plate was continuously subjected to steps similar to Example 1, of the treatment of the aluminum plate, the provision of a subbing layer, the coating of a light-sensitive layer and the superimposition of a polyester base thereon, except that either the light-sensitive layer was not coated on both edges of the continuous aluminum plate, or both edges alone were coated in a thinner coating thickness so that a thickness of the light-sensitive layer lower than an average height of uneven surface roughness of the grained aluminum plate was obtained, at the coating step.

By these two methods, printing plates having delamination edges at least at one edge thereof were prepared.

Example 4 In Example 2, benzoyl peroxide in an amount of 2% based on the trimethylolpropane trimethacrylate was added to the light-sensitive composition, which was coated as a light-sensitive layer. The coated layer was dried for 2 mins at temperatures not exceeding 60"C. In this case, no thermal polymerization occurred upon coating and drying. A lithographic printing plate was prepared, otherwise identical with Example 2. The thus-obtained printing plate was cut finished in a size of 40 cm wide and 60 cm long.

Thereafter, one edge of 1 cm was left in the longitudinal direction and the remaining portions were covered with another aluminum plate. The delamination edge 1 cm wide was heated with an infrared heater to cause thermal polymerization at the delamination edge of 1 cm in the light sensitive layer.

Example 5 A continuous web of a three layer-superimposed peel-apart developing type lithographic printing plate comprising (a) an aluminum plate, (b) a light-sensitive layer and (c) a polyethylene terephthalate film was obtained in a manner similar to Example 2 except that 0.4 g of 1, 1-bis-(p-dimethylaminophenyl)ethylene was further incorporated in the lightsensitive layer composition and a solvent mixture of toluene and methyl ethyl ketone (1:1 weight ratio) was used as a solvent in place of the toluene, in Example 2.

The printing plate was cut finished in a size of 30 cm wide and 42 cm long, one edge, 1 cm wide, of which was exposed to light in the breadthwise direction as shown in the Figures (see Figure 7 or Figure 9).

A blue image was obtained on the exposed portions and the exposed portions became capable of a very easy delamination.

Example 6 Chlorinated Polyethylene (Cl content; not less than 66 wt%, made by Sanyo Kokusaku Pulp Co., Ltd. under the tradename of "Superchlon HA") 10 g 2-t-Butylanthraquinone 15 g Hydroquinone 0.1 g Pigment (made by Ciba Co., Ltd under the tradename of Microlith Blue 4GT) (CI 74160) 0.3 g Methyl Ethyl Ketone 100 ml Toluene 20 ml A light-sensitive solution of the above described composition was prepared. A part of the solution was coated on a polyethylene terephthalate (PET) film having a thickness of 25 1 using a coating rod. The coated layer was driedsfor 10 mins at 80"C. A triacetyl cellulose (TAC) film having a thickness of 25 F was superimposed thereon to obtain a three-layered laminate film of (a) PET, (b) light-sensitive layer and (c) TAC. While slitting the web into widths of 25 cm, at least one edge portion thereof was irradiated with actinic radiation through an opening portion having letters or patterns from the TAC side to achieve side printing as shown in Figure 10 and Figure 11.

The TAC cover film of the thus obtained dry film resist was removed as in an ordinary dry film resist and laminated on a copper base plate. A wiring pattern was imagewise exposed. followed by peel-apart development to provide a resist for preparing a printed circuit on the copper base plate. The delamination edge which had been previously provided at the edge portion upon peel-apart development was not adhered to the copper plate and was useful as a delamination edge for peel-apart development when the light-sensitive layer and PET film were laminated on the copper plate.

Example 7 In a manner similar to Example 1, a light-sensitive element having press laminated thereto a polyethylene terephthalate film as a peel-apart sheet was prepared. The element was cut into a length of 60 cm and a width of 40 cm. At one edge of the element, a polyester adhesion tape (Polyester Adhesion Tape No. 31, manufactured by Nitto Denko Co., Ltd.) having a width of 10 mm was adhered to the peel-apart sheet with a 5 mm overlap between the peel-apart sheet and the adhesion tape, the adhesion tape being composed so as to expose an adhesive composition layer having a width of 5 mm at one edge thereof and the remaining portion having a width of 12 mm covered with paper.

Thereafter, the element was subjected to treatments subsequent to imagewise exposure in a manner similar to Example 1 to obtain similar results to Example 1.

Example 8 In a manner similar to Example 1, a light-sensitive element having press-laminated thereto a polyethylene terephthalate film as a peel-apart sheet was prepared. The element was cut into a length of 60 cm and a width of 40 cm. A polyester adhesion tape (Polyester Adhesion Tape no. 31) having a width of 18 mm was adhered to the peel-apart sheet such that one edge portion of the adhesion tape having a width of 4 mm overlapped one edge of the element. Then, a polyethylene terephthalate film having a width of 14 mm and a thickness of 16 F was adhered to the exposed 14 mm wide adhesive composition layer of the adhesion tape which did not contact the peel-apart sheet.

The element was then subjected to treatments subsequent to imagewise exposure in a manner similar to Example 1 but using the tape to assist delamination, to obtain similar results as in Example 1.

Example 9 A solution of an adhesive composition having the following composition was prepared.

Natural Rubber (smoked sheet) 10 g Glycerin Ester of Hydrogenated Rosin 10 g Toluene 100 ml The above described composition was coated onto a portion having a width of about 5 mm from one edge of a polyethylene terephthalate film tape having a thickness of 100 eel and a width of 20 mm. The tape was dried at 900C for 20 mins to prepare an adhesion tape (referred to as Adhesion Tape Sample 1).

On the other hand, a light-sensitive element having press laminated thereto a polyethylene terephthalate film was prepared in a manner similar to Example 1. The element was cut into a length of 60 cm and a width of 40 cm. Thereafter, Adhesion Tape Sample 1 previously prepared and the peel-apart sheet were arranged so as to overlap the adhesive composition layer of the adhesion tape and the edge of the peel-apart sheet.

The element was then subjected to treatments subsequent to imagewise exposure in a manner similar to Example 1 but using the tape to assist delamination to obtain similar results as in Example 1.

Example 10 The procedures of Example 9 were repeated except that the same adhesive composition as in Example 9 was coated in a width of 5 mm from one end of the glossy surface of patronen paper having a width of 20 mm.

WHAT WE CLAIM IS: 1. A method of producing an image which comprises (1) imagewise exposing a light-sensitive material comprising, in order, (a) a flexible film, (b) a light-sensitive layer comprising a light sensitive composition, and (c) a support, in which either one of said flexible film or said support is capable of transmitting actinic radiation to which said light-sensitive layer is sensitive and the adhesion of said light-sensitive layer to the film or the support is altered upon irradiation by said actinic radiation so that, after imagewise exposure, the light-sensitive layer is separated in a condition where one of the exposed areas or the unexposed areas is adhered to the support and the other is adhered to the film when the material is peeled apart, (2) peeling-apart the film to form the image on the support, and (3) before the imagewise exposure providing the light-sensitive material with a means facilitating peeling-apart of the flexible film from the remainder of the material before said peeling-apart.

2. A method as claimed in Claim 1, wherein said means facilitating peeling-apart comprises at least a part of at least one edge portion of said flexible film protruding from the remainder of said light-sensitive material.

3. A method as claimed in Claim 1, wherein portions of the support are cut away so that the light-sensitive layer and flexible film can readily be grasped above the cut away portions of the support.

4. A method as claimed in Claim 2, wherein the support for at least two pieces of the material was previously provided with through-holes therein at definite intervals prior to laminating said light-sensitive layer and said flexible film and said light-sensitive material was cut through the centres of said through-holes to form the cut away portions at the resultant cut edges.

5. A method as claimed in Claim 1, wherein said means facilitating peeling-apart is provided by irradiating said light-sensitive material with actinic radiation only in at least one peripheral strip to provide a peelable portion.

6. A method as claimed in Claim 5, wherein said peelable strip is indicated by a print-out image.

7. A method as claimed in Claim 1, wherein said means facilitating peeling-apart is provided by, before the exposure, adhering a part of a piece of an adhesion tape comprising a flexible support having a layer of an adhesive composition on one surface thereof to a part of said flexible film (a) or said support (c) so as to cause an overlap between said adhesion tape and said flexible film (a) or said support (c).

8. A method as claimed in Claim 7, wherein said adhesive composition is a pressure-sensitive adhesive composition.

9. A method as claimed in Claim 8, wherein an adhesive composition is present on said adhesion tape only at one edge of said flexible support in a width corresponding to the overlapping portion of said adhesion tape and said flexible film (a) or said support (c).

10. A method as claimed in Claim 8, wherein paper or a flexible synthetic resin film is adhered to the remaining area of the adhesive composition of said adhesion tape other than the overlapping portion of said adhesion tape and said flexible film (a) or said support (c).

11. A method as claimed in Claim 7, wherein said adhesive composition is a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Natural Rubber (smoked sheet) 10 g Glycerin Ester of Hydrogenated Rosin 10 g Toluene 100 ml The above described composition was coated onto a portion having a width of about 5 mm from one edge of a polyethylene terephthalate film tape having a thickness of 100 eel and a width of 20 mm. The tape was dried at 900C for 20 mins to prepare an adhesion tape (referred to as Adhesion Tape Sample 1). On the other hand, a light-sensitive element having press laminated thereto a polyethylene terephthalate film was prepared in a manner similar to Example 1. The element was cut into a length of 60 cm and a width of 40 cm. Thereafter, Adhesion Tape Sample 1 previously prepared and the peel-apart sheet were arranged so as to overlap the adhesive composition layer of the adhesion tape and the edge of the peel-apart sheet. The element was then subjected to treatments subsequent to imagewise exposure in a manner similar to Example 1 but using the tape to assist delamination to obtain similar results as in Example 1. Example 10 The procedures of Example 9 were repeated except that the same adhesive composition as in Example 9 was coated in a width of 5 mm from one end of the glossy surface of patronen paper having a width of 20 mm. WHAT WE CLAIM IS:

1. A method of producing an image which comprises (1) imagewise exposing a light-sensitive material comprising, in order, (a) a flexible film, (b) a light-sensitive layer comprising a light sensitive composition, and (c) a support, in which either one of said flexible film or said support is capable of transmitting actinic radiation to which said light-sensitive layer is sensitive and the adhesion of said light-sensitive layer to the film or the support is altered upon irradiation by said actinic radiation so that, after imagewise exposure, the light-sensitive layer is separated in a condition where one of the exposed areas or the unexposed areas is adhered to the support and the other is adhered to the film when the material is peeled apart, (2) peeling-apart the film to form the image on the support, and (3) before the imagewise exposure providing the light-sensitive material with a means facilitating peeling-apart of the flexible film from the remainder of the material before said peeling-apart.

11. A method as claimed in Claim 7, wherein said adhesive composition is a

heat-sensitive composition becoming adhesive on heating.

12. A method as claimed in Claim 11, wherein said composition is not adhesive at a temperature of 10 to 40"C.

13. A method as claimed in Claim 7, wherein said overlap of the adhesion tape is with said flexible film (a).

14. A method as claimed in any one of the preceding claims, wherein said light-sensitive composition comprises at least an ethylenically unsaturated monomer, a high molecular weight binder and a photopolymerization initiator.

15. A method as claimed in any of Claims 1 to 14, wherein said flexible film (a) is a synthetic resin film capable of transmitting actinic radiation to which said light-sensitive layer is sensitive.

16. A method as claimed in Claim 15, wherein said synthetic resin film is a polyethylene terephthalate film.

17. A method as claimed in Claim 15, wherein said synthetic resin is a polyethylene film or a polypropylene film.

18. A method as claimed in any of Claims 1 to 17, wherein said support (c) is a metal plate.

19. A method as claimed in Claim 18, wherein said plate is an aluminum plate or a grained and anodically oxidized aluminum plate.

20. A method of producing an image as claimed in Claim 1, substantially as hereinbefore described with reference to any of the foregoing Examples.

21. A material bearing an image formed by a method as claimed in any preceding claim.

22. A light-sensitive material capable of being developed by being peeled-apart, comprising, in order, (a) a flexible film, (b) a light-sensitive layer comprising a light-sensitive composition, and (c) a support, in which either one of said flexible film or said support is capable of transmitting actinic radiation to which said light-sensitive layer is sensitive and said light-sensitive layer, upon imagewise exposure, has an adhesion to the support different from its adhesion to the flexible film at both exposed areas and unexposed areas of the light-sensitive layer so that after imagewise exposure, the light-sensitive layer is separated in a condition where either one of the exposed areas or unexposed areas is adhered to the support and the other is adhered to the flexible film when the flexible film is peeled apart, and the material is, before imagewise exposure, provided with a means facilitating peeling-apart of the flexible film from the remainder of the material.

23. A light-sensitive material as claimed in Claim 22, wherein said means facilitating peeling apart comprises at least a part of at least one edge portion of said flexible film (a) protruding from the remainder of said light-sensitive material.

24. A light-sensitive material as claimed in Claim 22, wherein only said support (c) is semicircularly indented.

25. A light-sensitive material as claimed in Claim 22, wherein said means facilitating peeling apart has been provided by adhering a part of an adhesion tape comprising a flexible support having a layer of an adhesive composition on one surface thereof to a part of said flexible film (a) or said support (c) so as to cause overlap between said adhesion tape and said flexible film (a) or said support (c).

26. A light-sensitive material as claimed in Claim 22, wherein said adhesive composition is a pressure-sensitive adhesive composition.

27. A light-sensitive material as claimed in Claim 26, wherein an adhesive composition is present on said adhesion tape only at one edge of said flexible support in a width corresponding to the overlapping portion of said adhesion tape and said flexible film (a) or said support (c).

28. A light-sensitive material as claimed in Claim 26, wherein paper or a flexible synthetic resin film is adhered to the remaining area of the adhesive composition of said adhesion tape other than the overlapping portion of said adhesion tape and said flexible film (a) or said support (c).

29. A light-sensitive material as claimed in Claim 25, wherein said adhesive composition is a heat-sensitive composition becoming adhesive on heating.

30. A light-sensitive material as claimed in Claim 25, wherein said overlap of said adhesion tape is with said flexible film (a).

31. A light-sensitive material as claimed in any of Claims 20 to 31, wherein said material is composed as described in any of Claims 14 to 19.

32. A light-sensitive material as claimed in Claim 22, substantially as hereinbefore described with reference to, or as shown in, Figures 1 to 3 or Figures 4 and 5 or Figures 6 and 7 or Figure 8 or Figures 9 to 11 or Figure 12 or Figure 13 of the accompanying drawings.

33. A light-sensitive material as claimed in Claim 22, substantially as hereinbefore described in any of the foregoing Examples.

34. An image formed by exposure and development of a light-sensitive material as claimed in any of Claims 22 to 33,.