GB2195782A

GB2195782A - Photosensitive elements

Info

Publication number: GB2195782A
Application number: GB08722051A
Authority: GB
Inventors: Thomas A Dunder
Original assignee: Hoechst Celanese Corp
Current assignee: CNA Holdings LLC
Priority date: 1986-09-19
Filing date: 1987-09-18
Publication date: 1988-04-13
Anticipated expiration: 2007-09-18
Also published as: GB8722051D0; JPS63101843A; DE3730881A1; GB2195782B

Description

1 GB2195782A 1

SPECIFICATION

Photosensitive elements This invention relates to photosensitive compositions, to elements containing them and, more 5 especially, to their use in the manufacture of color proofs.

In the graphic arts, it is desirable to produce a color proof to assist a printer in correcting a set of photomasks which will be used in exposing printing plates. The proof should reproduce the color quality that will be obtained during the printing process. The proof should be;T consistent duplicate of the desired half tone or line image, and should neither gain nor lose 10 color. Visual examination of a color proof should reveal the following:

1. Any defects on the photoma8k.

2. The best color rendition to be expected from press printing of the material.

3. The correct gradation of all colors and whether grays are neutral.

4. The need, if any, for subduing any of the colors and/or giving directions for altering the 15 film photomask before making the printing plates.

Color proofing sheets for multi-colored printing have heretofore been made by using a printing press proof which requires taking all the steps necessary for actual multicolor printing. Such a conventional method of color proofing is costly and time consuming. Alternative color proofing methods have therefore been developed to simulate the quality of press proofs. There are two 20 known types of photographic color proofing methods, namely the surprint type and the overlay type.

In the overlay type of color proofing, an independent transparent plastic support is used for producing an image of each color separation film. A number of such supports carrying colored images superimposed upon each other and placed on a white sheet produce a color proof. This 25 type of color proofing has the disadvantage that the superimposed plastic supports tend to darken the color proofing sheet and, as a result, the impression of the color proofing sheet thus prepared becomes vastly different from copies actually obtained by a conventional printing press proof. The primary advantage of the method is that it is quick and can serve as a progressive proof by combining any two or more colors in register. 30 In the surprint method, a color proofing sheet is prepared by successively producing images of different colors from different color separation films onto a single receiver sheet. This is done by utilizing a single opaque support and by applying toners, photosensitive solutions or coatings of photosensitive materials of corresponding colors to the opaque support in succession. An example of this approach is described in U.S. Patent No. 3,671,236. An advantage of the 35 surprint type of color proof is that the color saturation is not influenced by superimposed plastic supports, and the method more closely resembles actual printing and eliminates the color distortion inherent in the overlay system.

Various processes for producing copies of an image embodying photopolymerization and thermal transfer techniques have been proposed in, for example, U.S. Patents Nos. 3,060,023; 40 3,060,024; 3,060,025,; 3,481,736; and 3,607,264. In these processes, a photopolymerizable layer coated on a suitable support is imagewise exposed to a photographic transparency. The surface of the exposed layer is then pressed into contact with the image receptive surface of a separate element and at least one of the elements is heated to a temperature above the transfer temperature of the unexposed portions of the layer. The two elements are then separated, 45 whereby the thermally transferable ' unexposed, image areas of the composite are transferred to the image receptive element. If the element is not precolored, the tacky unexposed image may now be selectively colored with a desired toner. The colored matter preferentially adheres to the clear unpolymerized material. U.S. Patent No. 3,574,049 provides a transfer process for printing a design on a final support which comprises (a) printing a design onto a temporary support, (b) 50 superimposing the temporary support and the final support, (c) applying heat and/or pressure to the superimposed structure formed in (b), and (d) separating the temporary support from the final support which retains the printed design. The affinity of the design for the temporary support is lower than its affinity for the final support.

In U.S. Patent -No. 3,721,557 a method of transferring colored images is described which 55 provides a stripping layer coated between the photosensitive element and the support. When the photosensitive layer is exposed to actinic light and developed, the more soluble portions are selectively removed to produce a visible image. The image-carrying support is pressed against a suitable adhesive coated receptor member and, subsequently, the carrier support sheet is stripped to accomplish the transfer of the image. A fresh layer of adhesive is applied to the 60 receptor for each subsequent transfer.

The present invention provides an improvement over previously proposed proofing systems which are susceptible to various deficiencies because of the considerable disparity in physical properties between the polymers used in the color and adhesive layers. Examples of this disparity include the glass transition temperature,'the coefficient of thermal expansion, and the 65 2 GB2195782A 2 percent elongation. Among the deficiencies resulting from the dissimilar physical properties are 11 pullout voids" on lamination, occasional incomplete solubility in the developer caused by disrup tion of the color/adhesive interface, and fracturing and distortion of color images upon storage, particularly at elevated temperatures..

Pullout voids occur when particles of dust, dirt, or other contaminants lie on the receiver base 5 surface. Upon lamination the adhesive flows and conforms itself about the particle while the brittle color layer is unable to do so and fractures at the point of highest stress. The fracture propagates through the adhesive layer causing a section of the transfer film to remain untrans ferred on the temporary carrier after lamination. By altering the tensile properties of the color layer such that it is no I, onger brittle, pullout voids are significantly reduced and any contamina- 10 tion by dirt or dust causes less of a problem.

The phenomenon of incomplete development is most often observed when the laminate composite is bent or flexed while still hot from the lamination process, especially as it exits from the laminator nip. In this manner a stress is applied to the color and adhesive layers, the adhesive is able to elongate in the direction of the stress to relieve the pressure, while the color 15 layer cannot do so and develops microfractures into which the hot, flowing adhesive may diffuse. This essentially causes a "mixing" of the two layers at their interface. Mixing of the adhesive into the color layer reduces the solubility of the color layer in developer. In thismanner areas of incomplete development are encountered which may again be averted by increasing the ability of the color layer to accommodate the stress. 20 Color layers constructed in accordance with the present invention do not substantially fracture or distort upon extended storage at room or elevated temperatures.

The invention uses a photosensitive layer containing a resinous binder composition, which composition contains primarily an acrylic acid/acrylate copolymer having a high tensile strength and percent elongation. This may optionally be admixed with one or more polymers selected 25 from polyvinyl acetals, styrenernaleic anhydrides, and the alcohol/vinyl acetate/vinyl acetal co polymers which are described more fully in U.S. Patent Application Serial No. 762,089, filed August 2, 1985, and EP-A 216,083, the disclosures of which are incorporated herein by reference.

The present invention provides an improved method for forming a colored image which 30 method comprises:

A) providing a photosensitive element which comprises, in order:

i) a substrate having a release surface; ii) a single photosensitive layer on said release surface, which photosensitive layer comprises a light sensitive, negative working, polymeric diazonium compound, at least one colorant and a 35 resinous binder composition, which composition contains a major amount of an acid-containing acrylic copoolymer having repeating units of the formulae M and N -CH 2 C (R 1) (COOR 2 and -CH 2 C (R 3) (COOH) - 40 (M) (N) 1 45 wherein:

R, and R3 independently represent H or CH3, R2 represents an alkyl group from 1'to 8 carbon atoms, and the molar ratio of N:M is within 50 the range of from 1:4 to 1:12, said copolymer having an average molecular weight in the range of from about 10,000 to about 300,000, and iii) an adhesive layer directly adhered to said color photosensitive layer, which adhesive layer comprises a vinyl acetate polymer and which adhesive layer has a softening point in the range of from about 60C to 180OC; and 55 B) either i) laminating said element with heat and pressure via said adhesive layer to a developer resistant receiver sheet; and removing said substrate by the application of peeling forces; and imagewise exposing said photosensitive layer to actinic radiation; or ii) imagewise exposing said photosensitive layer to actinic radiation; and laminating said ele- 60' ment with heat and pressure via said adhesive layer to a developer resistant receiver sheet; and removing said substrate by the application of peeling forces; or iii) laminating said element with heat and pressure via said adhesive layer to a developer resistant receiver sheet; and imagewise exposing said photosensitive layer to actinic radiation; and removing said substrate by the application of peeling forces; and 65 3 GB2195782A 3 Q removing the nonexposed areas of said photosensitive layer with a suitable liquid developer, which removing is conducted at a temperature at which said adhesive layer is substantially nontacky and, preferably, D) repeating steps A through C at least once with another photosensitive element having at least one different colorant. 5 In carrying out the method of the invention,. a photographic element which broadly comprises a substrate having a release surface, a colored photosensitive layer on the release surface and an adhesive layer on the photosensitive layer is used. Optional additional layers containing antihalation materials, adhesion promoters or release agents may also be used.

In the preferred embodiment, the substrate is composed of a dimensionally and chemically 10 stable base material which does not significantly change its size, shape or chemical properties as the result of the heating, coating, or other treatments which it must undergo. One preferred material is polyethylene terephthalate. In the usual case it has a thickness of from about 1 to about 10 mils (about 0.025 to 0.25 mm), a more preferred thickness is from about 2-5 mils 15_ (about 0.05 to 0.13 mm) and most preferably from about 2-3 mils (about 0.05 to 0.075 mm). 15 Suitable films include Hostaphan 3000, available from American Hoechst Corporation, Mylar D, available from DuPont and Melinex grades 0; 052, 442; 516 and S, available from ICI. The surface of the structure may be smooth or may be provided with a matte texture by various methods, many such methods being known in the art.

Trade Marks 20 Matte films include Melinex 377 and 470 from ICI. These materials have the property of giving the final image a desired matte finish without any extra steps. The gloss of the final image may be controlled by selected the matte finish of the temporary support, because the top layer of the final image is originally in contact with this matte surface. (This does not occur when there is a 25 separate release layer between the temporary support and the photosensitive layer.) An addi tional advantage of coating on a matte surface is that subsequent transferred layers generally adhere better to a rough surface than to a smooth surface.

A similar matte finish of the final image may be obtained by embossing the shiny, top surface of the image with a matte material, such as described above. This is done by laminating 30 together the final image and matte material under pressure and temperature. The matte material is then generally removed after lamination. The advantage of this method is that the finish of the final proof may be varied. Furthermore, the matting material may be re- used.

A third method for producing a matte finish uses a heat transferable layer, such for example as Butvar 90, available from Monsanto, coated onto a film with a rough surface, such as 35 Melinex 329, available from ICL The transferable layer is laminated to the final image under pressure and temperature. Then the film with the rough surface is peeled off. The rough surface of the transferred layer imparts a matte finish to the. final image. The advantages are that all the layers appear matte and that the extra transferred layer protects the image. U.S. Patents Nos.

4,294,909 and 4,376,159 also suggest various methods for making a matte surface. 40 Trade, Mark In any event, the substrate should have a release surface, that is, it must be capable of releasably holding the photosensitive layer thereto. This may be accomplished either by the substrate surface being inherently releasable, being rendered releasable by a suitable treatment or 45 being provided with a release layer over the substrate surface. Such a release layer may comprise polyvinyl alcohol.

Releasably bonded to the release surface is the photosensitive layer. The photosensitive layer broadly comprises at least one photosensitizer, colorant, and binding resin, and may comprise other optional ingredients such, for example, as plasticizers, acid stabilizers, surfactants, anti50 static compositions, uv absorbers and residual coating solvents.

The photosensitizer is preferably a light sensitive, polymeric diazonium salt. The most preferred phQtosensitizer is the polycondensation product of a 3-methoxy-4-diazo- diphenylamine salt and 4,4'-bis-methoxy methyl-diphenyl ether, precipitated as mesitylene sulfonate as taught in U.S.

Patent No. 3,849,392. Other suitable photosensitizers described in that patent and in U.S. Patent 55 No. 4,436,804 may be used. The diazo compounds of choice are preferably soluble in organic solvents.

Suitable binding resins are substituted or unsubstituted acid-containing acrylic copolymers having units of the formulae M and N as defined above. F12 advantageously represents the methyl, ethyl, n-butyl, n-octyl or 2-ethylhexyl radical. 1 60 The ratio of acid monomer units N to non-acid monomer units M correspond to an acid component in the range of from about 8% to about 20% of the copolymer.

Polymers having such a structure include Elvacite (DuPont) 2013, 2014, and 2028, Carboset (B.F. Goodrich) 514-A, 515, 525, 526, XL-27, and XL-44, Cyanamid CY-XC- 401 1, and Mocryl 151 (AO Polymer). 65 4 GB2195782A 4 In the preferred embodiment the aforesaid copolymers have a molecular weight in the range of from about 25,000 to about 250,000 and more preferably from about 150,000 to about 250,000. A mixture- of two or more of the copolymers may be used; the copolymer or mixture of the copolymers may be the sole binder constituent of the layer and advantageously repre sents the major binder constituent, and preferably represents at least'80% of the binder con- 5 stituent.

Suitable polymers for modifying the acrylic-based color layer include styrene-maleic anhydride polymers in both the half acid/half ester form and as the diacid such, for example, as Scripset (Monsanto) 520, 540, and 550 and SMA (Arco) 1440, 17352, and (Monsanto) B- 72, B-79, and B-90 and polyvinyl acetal/acetate/alcohol terpolymers such as those described in the above- 10 mentioned U.S. Patent Application Serial No. 762,089 and EP-A 216083.

If present, these terpolymers are present in limited proportions only, and, preferably constitute at most 20% by weight of the binder in the composition. They comprise units of each of the general types A, B and C in an ordered or random sequence in the resin and wherein A is present in said resin at about 5% to about 20% by weight and comprises groups of the formula 15 -CE2CH(O(CO)CH3)_, - B is present in said resin at about 4% to about 30% by weight and comprises groups of the formulp 20 -CH2CH(OH)-, and C is present in said resin at about 50% to 91 % by weight and comprises acetal groups of the formulae 25 CH2 -CH CH- -CH- CH- -CH- 30 0 0 0 0 CH II), CH and III) H-C-R 1 1 1 35 R R 0 1 40 where R is lower alkyl or hydrogen, and wherein in component C said group 1) is present from about 75% to about 85%; group 11) is present from about 3% to about 5%; and group 111) is present from about 10% to about 22%. The resins advantageously have a molecular weight of from about 5,000 to about 100,000.

The colorants useful for the present invention include, for example, various classes of dyes 45 and pigments. In the most preferred embodiment, pigments having an average particle size of about 1 micrometer or less are used.

Pla sticizers which may optionally be incorporated into the photosensitive layer include those of the phthalate and phosphate types. Preferred plasticizers include dibutyl phthalate and dimethyl phthalate. Acid stabilizers include phosphoric acid and p-toluene sulfonic acid. 50 These ingredients may be blended with such compatible solvents as ethanol, methyl cellosolve and methyl ethyl ketone, coated on the release surface, and dried. In the preferred emodiment, the photosensitive layer has a coating weight between approximately 0.1 and 5.0 g/M2. The most preferred weight is from about 0.5 to 2.0 g/M2.

In the preferred embodiment, the photosensitizer is present in the photosensitive layer in an 55 amount of from about 5 to about 40 percent by weight, more preferably from about 10 to about 35 percent by weight.

In the preferred embodiment, the colorant is present in the photosensitive layer in an amount of from about 10 to about 40 percent by weight, more preferably from about 13 to about 34 percent by weight. 60 In the preferred embodiment, the binding resin is present in the photosensitive layer in an amount of from about 25 to about 80 parts by weight, more preferably from about 32 to about parts by weight.

In the preferred embodiment, the ratio of the acrylic to the other modifying polymers is from 5:1 to 1:2, more preferably from 3:1 to 1:1. 65 GB2195782A 5 In the preferred embodiment, the plasticizer, when one is.used, is present in the photosensi- tive layer in an amount of up to about 20 parts by weight, more preferably up to about 15 parts by weight and most preferably from about 12 to about 15 parts by weight.

In the preferred embodiment, the acid stabilizer, when one is used, is present in the photosen- sitive layer in an amount of up to about 10 parts by weight. 5 Typical formulations for the photosensitive layer include:

Formulation i.

10 Yellow Magenta Cyan Black methyl cellosolve 40 40 40 40 15 methyl ethyl ketone 40 40 40 40 tetrahydrofuran 10 10 10 10 20 butyrolactone 5 5 5 4 C.arbos-.t XL-27 1 0.75 0.75 1 25 Elvacite 2014 0.5 0.25 0.25 -- Carboset 525 -- 0.25 0.25 1.5 SMA 2625 0.5 0.75 0.75 0.5 30 Above diazo from U.S.

Patent No. 3,849,392 1.7 1.5 1.5 1.75 35 phthalocyanine blue pigment -- -1 -- yellow pigment 1.3 -- 40 magenta pigment -- 1 -- -- black pigment -1.25 45 optical density 0.9 1.3 1.2 1.6 6 GB2195782A 6 Formulation II.

Yellow Magenta Cyan Black 5 . methyl cellosolve 41 47.3 42 41.6 methyl ethyl ketone 42.6 47.8 41 41.6 10 A butyrolactone 10 10 10 Carboset XL-44 0.5 1 15 Carboset 525 2 1 1 1.9 Butvar B-90 1 0.25 0.5 20 Scripset 540 1 1 1.5 2 Above diazo from U.S.

Patent No. 3,849,392 -1.35 0.7 1.3 2 25 phthalocyanine blue pigment 1.7 yellow pigment 1.05 30 magenta pigment 1.45 black pigment -- -- 0.9 35 optical density 0.9 1.3 1.2 1.6 40 Scripset resins are available from Monsanto. SMA resins are available from Arco. Carbosets are available from B. F. Goodrich. Elvacites are available from DuPont.

The adhesive layer comprises polyvinyl acetate and may optionally contain such other desired 45 components as uv absorbers, anti-static compositions and plasticizers. Useful polyvinyl acetates non-exclusively include Mowilith DM-6, 20, 25, 30 and mixtures thereof, available from Hoechst AG. These are usually dispersed in water, or dissolved in methyl isobutyl ketone or n-butyl acetate or other solvent compositions for coating on the photosensitive layer. The coating is then dried to a weight of from about 5 to about 30 g/M2 more preferably from about 10 to 50 about 20 g/M2. The layer may optionally contain a uv absorber such for example as Uvinul D-50 from G.A.F. It may also contain a plasticizer such for example as Resoflex R-296, available from Cambridge Industries. It may also contain antistats, such for example as Gafac and Gafstat from G.A.F. It may also contain other resins, such for example as Nitrocellulose RS 1/2, available from Hercules. The adhesive layer should not be tacky to the touch, during storage or during 55 development of the photosensitive element. The layer should have a softening point of at least 600C, advantageously in therange from about 600C to about 180'C, preferably 60 to 120C, more preferably 60'C to 100'C. In the preferred embodiment, the polyvinyl acetate is present in the adhesive layer in an amount of greater than about 50 percent by weight. The plasticizer may be present in an amount of up to about 30 pprcent by weight, the uv absorber up to about 20 60 percent by weight, and other resins up to about 50 percent by weight.

Typical adhesive formulations include:

7 GB2195782A 7 Water 50.00 Mowilith DM-22 50.00 11. n-butyl acetate 78.00 5 - Resoflex R-296 1.00 - Mowilith 30 21.00 111.- n-butyl acetate 68.70- Uvinul D-50 1.30 10 - Mowilith 20 30.00 In operation, the photosensitive element is laminated to a receiver sheet via the adhesive layer.

The receiver sheet should be resistant to any adverse effects which may be caused by the 15 developer of choice. For example, the receiver sheet should be water resistant if aqueous developers are used. Plastic or plastic coated receiver sheets are useful for this purpose.

Useful receiver sheets include Melinex 329; 339; 994 and 3020 from ICI. Other white and nonwhite receiver sheets may also be used. Rough textured and/or adhesion promoted surfaces are preferred for the receiver, which must be able to withstand the laminating and development 20 processes.

Lamination may be conducted by putting the receiver sheet in contact with the adhesive side of the colored composite and then introducing the two materials into the nip of a pair of heated laminating rollers under suitable pressure. Suitable laminating temperatures usually range from about 60C to about 90'C, preferably about 75'C to about 85'C. After lamination, the substrate 25 is peeled away, usually merely employing manual peeling forces. The adhesive and photosensi tive layers thus remain on the receiver sheet.

The photosensitive layer is imagewise exposed by means well known in the art either before or after lamination. Such exposure may be conducted by exposure to a uv light source through a photomask under vacuum frame conditions. Exposure may be performed with actinic light 30 through a conventional negative flat. Exposures after lamination and peel apart are preferred for emulsion-to-emulsion contact. Mercury vapor discharge lamps are preferred over metal halide lamps. Filters may be used to reduce light scattering in the material.

After lamination, peel apart, and exposure, the photosensitive layer is developed by dissolving the non-exposed area in a suitable developer and dried. The adhesive layer is not removed by 35 this development. Suitable developers include, for example:

I.- - water 95.0 - sodium decyl sulphate 3.0 40 - disodium phosphate 1.5 sodium metasilicate 0.5 JI. - water 89.264 45 - monosodium phosphate 0.269 - trisodium phosphate 2.230 - sodium tetradecyl sulfate 8.237 50 Any developer solution which satisfactorily removes the non-exposed areas of the photosensi- tive layer after exposure while retaining the image areas may be used. The selection of devel oper is well within the ability of the skilled artisan.

The process may be repeated, another photosensitive element having a different color being laminated to the same receiver sheet over the previously formed image. In the usual case, four 55 colored layers are employed to produce a full color reproduction of a desired image. These are normally cyan, magenta, yellow and black.

The following examples illustrate the invention:

Example 1 60

Four photosensitive solutions of cyan, yellow, magenta, and black are produced in accordance with the photosensitive formulations 11 described above. The pigment is introduced as a disper sion of propylene glycol monomethyl ether, Carboset XL-44, and the appropriate pigment. The solutions are coated and dried separately to the required optical density onto 3 mil (about 0.075 mm) Melinex 516 polyester film as a temporary support. The layer weights are roughly 1.3 g/M2 65 8 GB2195782A 8 for cyan, 0.9 g/M2 for yellow, 1.2 g/M2 for magenta, and 1.6 g/M2 for black. The adhesive solution, in particular adhesive formulation number 11 above, is coated on top of the photosensi tive layers and dried to a layer weight of 12 g/m2. The yellow composite is then laminated at 80'C with the adhesive side onto one side of a 7 mi ' I (about 0.18 mm) Melinex 3020 polyester receiver sheet. The temporary support is peeled away after lamination, leaving the adhesive and 5 photosensitive layers on the receiver sheet. The yellow photosensitive layer is then exposed to actinic light through a photographic flat for the yellow color. The receiver sheet with the exposed yellow layer is then immersed for 15 seconds in developer 11 above at 270C with gentle pad rubbing on the photosensitive side. The nonexposed, yellow areas are thereby washed off -.10 and the exposed areas remain during development. The adhesive layer is not affected by the 10 developer. After this treatment, the imaged material is rinsed and then dried. The magenta composite is then laminated as before onto the imaged, yellow side of the receiver sheet. The temporary support is removed as before. The magenta layer is then exposed through the magenta flat. It is then processed as with the yellow. The magenta is followed in a like manner by cyan and then by black to give a four color image which is an accurate representation of the 15 original from which separations are prepared.

Example /I

Black coatings are made for comparison using the black formulae based on acrylic resin as well as a black coating based entirely on Scripset 540 polymer using the following formulations: 20 Material Black I Black II methyl cellosolve 32 32 25 Dowanol PM 10 10 methyl ethyl ketone. 41 41 30 butyrolactone 5 5 diacetone alcohol 5 5 dimethyl phthalate 1.0 35 Scripset 540 0.5 3.0 Carboset XL-44 1.0 40 Carboset 525 2.0 Put-var B-90 0.5 45 above diazo from U.S.

Patent No. 3,849,392 2.0 2.0 black pigment 1.0 1.0 50 The coatings are prepared in the method described in Example 1 and are likewise overcoated, transferred, exposed, and developed. Upon lamination, an average of 2 to 4 pullout voids are observed in Black 11 coatings, as compared to an average of 0 to 1 pullouts in the Black 1. The final exposed and developed images are stored at 50'C and are observed on a regular basis for 55 signs of fracture. Black I images survive such storage for two months; Black 11 images display fractures in image areas in about 2 hours and show distortion of halftone dots after 18 hours, rendering 'the images useless for a graphic arts application.

Claims

CLAIMS 60

1. A method for forming a colored image which comprises:

A) providing a photosensitive element which- comprises, in order:

i) a substrate having a release surface;, ii) a single photosensitive layer on said release surface, which photosensitive layer comprises a light sensitive, negative working, polymeric diazonium compound; at least one colorant and a 65 9 GB2195782A 9 resinous binder composition, which composition contains a major amount of an acid-containing acrylic copolymer having repeating units of the formulae M and N -CH 2 C (R 1)(COOR 2)- and -CH 2 C(R 3)(COOH)- 5 10. (M) (N) 10 wherein:

R, and R3 independently represent H or CH3, R2 represents an alkyl group having from 1 to 8 carbon atoms, and the molar ratio of N:M is 15 within the range of from 1:4 to 1:12, said copolymer having an average molecular weight-in the range of from about 10,000 to about 300,000, and iii) an adhesive layer directly adhered to said photosensitive layer, which adhesive layer com- prises a vinyl acetate polymer and which adhesive layer has a softening point in the range of from about 60oC to 180OC; and 20 B) either i) laminating said element with heat and pressure via said adhesive layer to a developer resistant receiver sheet; and removing said substrate by the application of peeling' forcesl and imagewise exposing said photosensitive layer to actinic radiation; or ii) imagewise exposing said photosensitive layer to actinic radiation; and laminating said ele25 ment with heat and pressure via said adhesive layer to a developer resistant receiver sheet; and removing said substrate by the application of peeling forces; or iii) laminating said element with heat and pressure via said adhesive layer to a developer resistant receiver sheet; and imagewise exposing said photosensitive layer to actinic radiation; and removing said substrate by the application of peeling forces; and 30 Q removing the nonexposed areas of said photosensitive layer with a suitable liquid developer, which removing is conducted at a temperature at which said adhesive layer is substantially nontacky.

2. The method of claim 1, wherein steps A through C are followed by applying at least one further photosensitive element having at least one-different colorant onto said receiver sheet 35 over the nonremoved portions of the previously laminated photosensitive layer or layers.

3. The method of claim 1 or claim 2, wherein said substrate comprises polyethylene tere- phthalate.

4. The -method of any one of claims 1 to 3, wherein said substrate has a matte surface.

5. The method of any one of claims 1 to 4, wherein said release surface on said substrate 40 comprises polyvinyl alcohol.

6. The method of any one of claims 1 to 5, wherein said photosensitive layer comprises the polycondensation product of a 3-methoxy-4-diazodiphenylamine salt and 4, 4'-bis-methoxy methyl diphenyl ether.

7. The method of any one of claims 1 to 6, wherein said photosensitive layer further 45 comprises one or more ingredients selected from plasticizers, acid stabilizers, antistatic compo sitions, uv absorbers and surfactants.

8. The method of any one of claims 1 to 7, wherein the coating weight of the photosensitive layer is within the range of from 0. 1 to 5.0 g/M2.

50-

9. The method of any one of claims 1 to 8, wherein the photosensitizer is present in the 50 photosensitive layer in an amount of from 5 to 40 percent by weight.

10. The method of any one of claims 1 to 9, wherein the colorant is present in the photosensitive layer in an amount of from 10 to 40 percent by weight.

11. The method of any one Of claims 1 to 10, wherein the binding resin is present in the photosensitive layer in an amount of from 25 to 80 percent by weight. 55 -

12. The method of any one Of claims 1 to 11, wherein a plasticizer is present in the photosensitive layer and is present in an amount of up to 20 percent by weight.

13. The method of any one of claims 1 to 12, wherein an acid stabilizer is present in the photosensitive layer and is present in an amount of up to 10 percent by weight.

14. The method of any one of claims 1 to 13, wherein the adhesive layer has a coating 60 weight of from 5 to 30 g/M2.

15. The method of any one of claims 1 to 14, wherein polyvinyl acetate is present in the adhesive layer in an amount of at least 50 percent by weight.

16. The method of any one of claims 1 to 15, wherein the adhesive layer further comprises one or more ingredients selected from uv absorbers, antistatic compositions, resins, nitrocellu- 65 GB2195782A 10 lose and plasticizers.

17. The method of claim 16, wherein the uv absorber is present in the adhesive layer in an amount of up to 30 percent by weight.

18. The method of claim 16 or claim 17, wherein the plasticizer is present in the adhesive layer in an amount of up to 20 percent by weight. 5

19. The method of any one of claims 1 to 18, wherein the laminating step is conducted at a temperature of from 60'12 to WC.

20. The method of any one of claims 1 to 19, wherein said binder composition further comprises one or more components selected from the group consisting of styrene/maleic anhy dride copolymers, polyvinyl acetals, and acetal/acetate/alcohol terpolymers. 10

2 1. The method of any one of claims 1 to 20, wherein said binder composition further comprises a resin comprising units of each of the general types A, B and C in an ordered or random sequence in the resin and wherein A is present in said resin at about 5% to about 20% ht and comprises groups of the formula by weig - 15 -CH2CH(O(C0)iCH,)-, B is present in said resin at about 4% to about 30% by weight and comprises groups of the formula 20 -CH2CH(OH)-, and C is present in said resin at about 50% to about 91 % by weight and comprises acetal groups of the formulae 25 RH 2 -CH CH- -CH-CH- -CH- 3G 1 1 1 1 1 30 0 0 0 0 U CH II) CH and III) H-C-R R 0 35 -CH- where R is lower alkyl or hydr'ogen, and wherein in component C said group 1) is present from 40 about 75% to about 85%; group 11) is present from about 3% to about 5%; and group 111) is present from about 10% to about 22%, the resin having a molecular weight of from about 5,000 to about 100,000.

22. The method of any one of claims 1 to 21, wherein the colorant is a pigment. Z

23. A photosensitive element which comprises 45 i) a substrate having a release surface; ii) a single photosensitive layer on said release surface, which photosensitive layer comprises a light sensitive, negative working, polymeric diazonium compound; at least one colorant and a resinous binder composition, which composition contains a major amount of an acid-containing acrylic copolymer having repeating units of the formulae M and N 50 -CH 2 C(R 1)(COOR 2 and -CH 2 C(R 3)(COOH) 55 (M) (N) 60 _ wherein R, and R, independently represent H or CH3, R2 is an alkyl group having from 1 to 8 carbon atoms, and the molar ratio of N: M is within the range of from 1:4 to 1:12, said copolymer having an average molecular weight in the range of from about 10,000 to about 300,000, and 65 GB2195782A 11 iii) an adhesive layer directly adhered to said photosensitive layer, which adhesive layer com- prises a vinyl acetate polymer and which adhesive layer has a softening point in the range of from about 600C to about 180'C.

24. The element of claim 23, wherein said substrate comprises polyethylene terephthalate.

25. The element of claim 23 or claim 24, wherein said substrate has a matte surface. 5

26. The element of any one of claims 23 to 25, wherein said release surface on said substrate comprises polyvinyl alcohol.

27. The element of any one of claims 23 to 26, wherein said photosensitive layer comprises the polycondensatiQn product of a 3-methbxy-4-diazodiphenylamine salt and 4,4'-bis-methoxyme thy[-diphenyl ether. 10

28. The element of any one of claims 23 to 27, wherein said photosensitive layer further comprises one or more ingredients selected from plasticizers, acid stabilizers, antistatic compo -sitions, uv absorbers and surfactants.

29. The element of any one of claims 23 to 28, wherein the coating weight of the photosen- sitive layer is within the range of from 0. 1 to 5.0 g/m2. 15

30. The element of any one of claims 23 to 29, wherein the photosensitizer is present in the photosensitive layer in an amount of from 5 to 40 percent by weight.

3 1. The element of any one of claims 23 to 30, wherein the colorant is a pigment.

32. The element of claim 31, wherein the pigment is present in the photosensitive layer in an amount of from 10 to 40 percent by weighf. 20

33. The element of any one of claims 23 to 32, wherein the binding resin is present in the photosensitive layer in an amount of from 25 to 80 percent by weight.

34. " The element of any one of claims 23 to 33, wherein a plasticizer is present in the photosensitive layer and is present in an amount of up to 20 percent by weight.

35. The element of any one of claims 23 to 34, wherein an acid stabilizer is present in the 25 photosensitive layer and is present in an amount of up to 10 percent by weight.

36. The element of any one of claims 27 to 35, wherein the adhesive layer has a coating weight of from 5 to 30 g/M2.

37. The element of any one of claims 23 to 36, wherein the adhesive layer further comprises one or more ingredients selected from uv absorbers, antistatic compositions, resins, nitrocellu- 30 lose and plasticizers.

38. The element of any one of claims 23 to 27, wherein polyvinyl acetate is present in the adhesive layer in an amount of at least 50 percent by weight.

39. The element of any one of claims 23 to 38, wherein a uv absorber is present in the adhesive layer and is present in an amount of up to 30 percent by weight. 35

40. The element of any one of claims 23 to 39, wherein -a plasticizer is present in the adhesive layer and is present in an amount of up to 20 percent by weight.

41. Th element of any one of claims 23 to 40, wherein said binder composition further comprises one or more components selected from the group consisting of styrene/maleic anhy dride copolymers, polyvinyl acetals, and vinyl acetal/acetate/alcohol terpolymers. 40

42. The element of any one of claims 23 to 41, wherein said binder composition further comprises a resin as specified in claim 21.

43. The method of claim 1, carried out substantially as described in either of the examples herein.

44. The element of claim 23, substantially as described in either of the examples herein.

45 45. A photosensitive element which comprises i) a substrate having a release surface; ii) a photosensitive layer and iii) a thermally activatable adhesive layer, the photosensitive layer comprising the acid-containing acrylic polymer specified in claim 1.

46. Any new feature hereinbefore described or any new combination of hereinbefore described features. 50 Published 1988 at The Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.