WO1995012147A1

WO1995012147A1 - Polyvinyl acetal resin having (meth)acrylic and urethane groups and photosensitive composition containing it

Info

Publication number: WO1995012147A1
Application number: PCT/US1994/012317
Authority: WO
Inventors: Wojciech A. Wilczak
Original assignee: Hoechst Celanese Corporation
Priority date: 1993-10-29
Filing date: 1994-10-27
Publication date: 1995-05-04

Abstract

A binder resin for photosensitive compositions, a process for producing such a binder, a photosensitive composition containing such a binder and a process for producing such a photosensitive composition, the binder comprising random units of (a) and (b) where a = 50-99 %, b = 1-50 %, and where R1 is hydrogen atom, a substituted or unsubstituted alkyl radical containing 1-6 carbon atoms, or a substituted or unsubstituted aryl radical; R2 is (i) or (ii), where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms.

Description

Polyvinyl Acetal Resin Having (Meth)acrylic and Urethane Groups and Photosensitive Composition Containing It

Background of the Invention The invention relates to a novel polyvinyl acetal resin which is suitable, in particular, as a binder for photopolymerizable compositions which are used in the area of graphic arts to prepare printing plates and color proofing films.

Photopolymerizable compositions consisting of a polymeric binder, an ethylenically unsaturated polymerizable monomer, and a photoinitiator are well known in the art. A photoimage is generated when such a composition is exposed to actinic radiation which polymerizes the exposed areas. The latent image is then differentiated from the unexposed areas by a variety of methods, including wet development (dissolving the unexposed areas in a liquid developer), dry peel-apart development (differentiation is based on preferential adhesion of exposed vs. unexposed areas to a substrate), dry toner development (image differentiation based on different tackiness of exposed vs. unexposed areas), etc. See for example U.S. Patents 4,940,646, 4,282,308 and 3,649,268 for details of those techniques.

In order for such photopolymerizable compositions to achieve sufficiently high photosensitivity, the amount of ethylenically unsaturated monomer in the composition must be relatively high, frequently approaching or exceeding 50% of the composition by weight. This renders the composition soft and tacky, necessitating, in the case of printing plates, the need for an expensive protective cover layer, and frequently causing, in the case of multilayer proofing films, unwanted migration of excess monomer into other layers. In case of wet-developable printing plates, excess of unreacted monomer ends up in spent developer, rendering it environmentally harmful.

Polyvinyl acetals have been used as binder resins for photosensitive compositions (U.S. Patents 4,631,245 and 4,940,646) due to ease of their chemical modification, and good lithographic properties. However, they have not been modified in such a way as to render them photocrosslinkable, thereby eliminating the above-described unwanted properties of photopolymerizable compositions.

Summary of the Invention

The present invention provides a polyvinyl acetal resin containing (meth)acrylic groups attached to the polymer via urethane linkages, rendering the polyvinyl acetal photocrosslinkable. The polyvinyl acetal of the present invention can serve as a binder in photopolymerizable compositions useful in the production of printing plates and color proofing films.

The present invention provides improved photopolymerizable compositions, in which the binder participates in the photocrosslinking, thus reducing the amount of monomer necessary to achieve good crosslinking, improving photospeed, and increasing toughness of the polymerized composition. The present invention also provides a photocrosslinkable polyvinyl acetal resin which develops strong adhesion to the adjoining surface when the photopolymerizable composition containing it is crosslinked.

The present invention relates to a binder resin for photosensitive compositions, the binder resin comprising random units of:

a)

where: a = 50-99%, b = 1-50%, and where:

R, is hydrogen atom, a substituted or unsubstituted alkyl radical containing

1-6 carbon atoms, or a substituted or unsubstituted aryl radical R, is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms. The present invention also relates to a photosensitive composition containing this resin, an ethylenically unsaturated polymerizable monomer, and a photoinitiator. In this resin R, is preferably n-butyl and R₂ is preferably

where Y is preferably ethyl and Z is preferably methyl.

The present invention also provides a resin comprising random units of:

where: a = 50-98% b = 1-50% c = 1-30% and a + b + c = 100% and where: R, is hydrogen atom, a substituted or unsubstituted alkyl radical containing 1-6 carbon atoms, or a substituted or unsubstituted aryl radical

R, is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of

1-4 carbon atoms, and

R₃ is an alkyl radical containing 1-4 carbon atoms.

The present invention also provides a photosensitive composition containing this resin, an ethylenically unsaturated polymerizable monomer, and a photoinitiator. In this resin R, is preferably n-butyl and R₂ is preferably

where Y is preferably ethyl and Z is preferably methyl.

The present invention further relates to a resin comprising random units of:

a)

where a = 50-98% b = 1-50% d = 1-30% and a + b + d = 100% and where

R_j is hydrogen atom, a substituted or unsubstituted alkyl radical containing

1-6 carbon atoms, or a substituted or unsubstituted aryl radical R_j is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of

1-4 carbon atoms

The present invention further relates to a photosensitive composition containing this resm, an ethylenically unsaturated polymeπzable monomer, and a photoinitiator In this resin R, is preferably n-butyl and R_; is preferably

where Y is preferably ethyl and Z is preferably methyl.

The present invention further provides a resin comprising random units of:

where: a = 50-99% b - 1-30% c = 0-30% d = 0-50%, and a + b + c + d = 100% and where:

R, is hydrogen atom, a substituted or unsubstituted alkyl radical containing 1-6 carbon atoms, or a substituted or unsubstituted aryl radical

R₂ is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of

1-4 carbon atoms,

R₃ is an alkyl radical containing 1-4 carbon atoms.

The present invention further provides a photosensitive composition containing this resin, an ethylenically unsaturated polymerizable monomer, and a photoinitiator. In this resin R, is preferably n-butyl and R₂ is preferably

where Y is preferably ethyl and Z is preferably methyl.

In addition, the present invention relates to a method for producing a photosensitive element which comprises: (A) providing a suitable substrate; (B) providing a photosensitive mixture, which comprises an organic binder, an ethylenically unsaturated polymerizable monomer, and a photoinitiator, wherein the binder is present in sufficient amount to bind the components into a uniform film, wherein the photoinitiator is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image differentiation when the photosensitive mixture is imagewise exposed to actinic radiation wherein the organic binder comprises a resin comprising random units of:

where: a = 50-99%, b = 1-30%, c = 0-30% d = 0-50%, and a + b + c + d = 100%; and where:

R, is hydrogen, a substituted or unsubstituted alkyl containing

1-6 carbon atoms, or a substituted or unsubstituted aryl, R₂ is

where Z is hydrogen or methyl, and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms, and

R₃ is an alkyl radical containing 1-4 carbon atoms; (C) coating the photosensitive mixture on a suitable substrate.

The present invention additionally relates to this process, wherein R, is preferably n-butyl and R₃ is preferably methyl and R₂ is preferably:

where Y is preferably ethyl and Z is preferably methyl. The substrates may include aluminum, a plastic or paper sheet or a polyester sheet. Detailed Description of the Invention

The photocrosslinkable polyvinyl acetals of the present invention con be obtained by reacting a polyvinyl acetal polymer containing free hydroxyl groups with a (meth)acrylated monoisocyanate. Suitable polyvinyl acetals include polyvinyl formal, propional, or polyvinyl butyral, nonexclusively. An example of such polyvinyl acetal polymers are those having the general formula:

— A— B— —

wherein a plurality of each of components A, B and C occur in an ordered or random sequence in the resin and wherein A is present in the polymer at about 1 % to about 20% by weight and comprises groups of the formula:

B is present in the polymer at about 1% to about 30% by weight and comprises groups of the formula:

and C is present in the polymer at about 50% to about 91% by weight and comprises acetal groups consisting of groups of the formula:

where R is lower alkyl or hydrogen. As used above, the term "lower alkyl" refers to a straight or branched chain hydrocarbon having from 1 to 8 carbon atoms and containing no unsaturation.

The molecular weight of the particular copolymer chosen as the starting material may vary from about 5,000 to about 200,000 and often depends upon the end use desired for the resultant binder resin. For instance, if the resin is to be used in the production of a lithographic printing plate, the copolymers are preferably those having higher molecular weights (i.e. about 50,000 to about 200,000). If the resin is to be used in the production of screens for screen printing applications, the copolymers are preferably those having lower molecular weights (i.e. about 5,000 to about 30,000). Suitable polyvinyl acetal copolymers have from about 1% to about 30% free hydroxyl groups, preferably from about 4% to about 20% and most preferably from about 6% to about 15%.

Commercially available polyvinyl acetal copolymers include Formvar and Butvar resins from Monsanto and Mowital resin from Hoechst. They are obtained by reacting polyvinyl alcohol with a monoaldehyde and contain up to about 30% of free hydroxyl groups. These hydroxyl groups are available for reaction with a (meth)acrylated monoisocyanate, according to the present invention. Such monoisocyanates include, nonexclusively: acryloyl isocyanate, methacryloyl isocyanate, isocyanatoethyl methacrylate.

The reaction conditions for reaction of isocyanates with compounds containing hydroxyl groups to produce urethanes are well known in the art. The reaction takes place in an organic solvent unreactive towards the isocyanate, for example tetrahydrofuran (THF), methyl ethyl ketone (MEK), ethyl acetate, etc. The reaction can be optionally catalyzed by well known catalysts such as dibutyltin dilaureate. Often, the isolation of the reacted polymer from the reaction mixture is not necessary, as the reaction is in many cases quantitative. After addition of an ethylenically unsaturated polymerizable monomer, a photoinitiator, and optional colorants and other additives, the mixture can be coated out of the reaction solvent, to provide an element of a printing plate or color proofing film, as desired.

The polymerizable monomer may comprise addition polymerizable, non- gaseous (boiling temperature above 100°C at normal atmospheric pressure), ethylenically-unsaturated compounds containing at least one and preferably at least two terminal ethylenically unsaturated groups, and being capable of forming a high molecular weight polymer by free radical initiated, chain propagating addition polymerization. The most preferred compounds of this type are acrylate or methacrylate monomers as are well known in the art. Suitable polymerizable monomers nonexclusively include triethylene glycol dimethacrylate, tripropylene glycol diacrylate, tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol tetraacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate, di-pentaerythritol monohydroxypentaacrylate, pentaerythritol triacrylate, bisphenol-A-ethoxylate dimethacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, and bisphenol A diepoxide dimethacrylate.

Free radical liberating photoinitiators are used and include any compound which liberate free radicals on stimulation by actinic radiation. Preferred photoinitiators nonexclusively include quinoxaline compounds as described in U.S.

Patent 3,765,898; the vicinal polyketaldonyl compounds in U.S. Patent 2,367,660; the alpha-carbonyls in U.S. Patents 2,367,661 and 2,367,670; the acyloin ethers in U.S. Patent 2,448,828; the triarylimidazolyl dimers in U.S. Patent 3,479,185; the alpha- hydrocarbon-substituted aromatic acyloins in U.S. Patent 2,722,512; polynuclear quinones in U.S. Patents 2,951,758 and 3,046,127; and s-triazines in U.S. Patents

3,987,037 and 4,189,323. The most preferred photoinitiators include 2,3-di(4- methoxyphenyl)quinoxaline, 9-phenylacridine, 2-biphenyl-4,6-bis-trichloromethyl-5- triazine, bis(2,4,5-triphenyl)imidazole and its derivatives, bis-trichloromethyl-s- triazines, thioxanthones and acetophenones.

Suitable substrates may comprise virtually any material which can withstand processes such as laminating and dry development. White plastic sheets, such as adhesion pretreated polyester Melinex 3020 film available from ICI, are useful for this purpose. Plastic coated paper sheets, such as polyethylene coated paper available from Schoeller, may also be used. Other bases may include wood, glass, metal such as aluminum sheet, paper and the like. Dyes may also be included to spectrally sensitize the photoinitiator, such as described in U.S. Patent 4,282,309 and 4,454,218, and European Patent Applications

0,179,448 and 0,211,615.

In the practice of the present invention, the photoinitiator component is preferably present in an amount ranging from about 0.01 to 20% based on the weight of the solids in the layer. A preferred range is from about 0.1 to 15%, more preferably from 1 to 10%.

In the practice of the present invention, the photoinitiator component is preferably present in an amount ranging from about 1 to 40% based on the weight of the solids in the photosensitive composition. A preferred range is from about 2 to 30%, more preferably from 5 to 20%.

Dyes and/or pigments are included to provide color to the image areas.

Preferred colorants for this invention are pigments rather than dyes. Light fast colorants are preferred. The pigments are typically dispersed with an organic binder in an organic solvent or mixture of organic solvents. The pigments may be organic or inorganic. They are ground to a small enough particle size to duplicate the particle size and color of equivalent inks. The median diameter is generally less than

1 micrometer.

Nonexclusive examples of colorants usable in the present invention are as follows: Permanent Yellow G (C.I. 21095), Permanent Yellow GR (C.I. 21100), Permanent Yellow DHG (C.I. 21090), Permanent Rubine L6B (C.I. 15850: 1),

Permanent Pink F3B (C.I. 12433), Hostaperm Pink E (73915), Hostaperm Red Violet ER (C.I. 46500), Permanent Carmine FBB (12485), Hostaperm Blue B2G (C.I. 74160), Hostaperm Blue A2R (C.I. 74160), and Printex 25. Most of these are products of Hoechst AG They can be used separately or blended for a desired color.

Other ingredients which may also be present are thermal polymerization inhibitors, plasticizers, tackifiers, oligomers, residual solvents, surfactants, inert fillers, antihalation agents, hydrogen atom donors, photoactivators, and optical brightening agents.

In a preferred embodiment of the present invention, the binder resin component is preferably present in an amount sufficient to bind the components in a uniform mixture and a uniform film when it is coated on a substrate. It is preferably present in an amount ranging from about 10 to about 90% based on the weight of the solids. A more preferred range is from about 20 to about 80%.

In the preferred embodiments, the polymerizable monomer is present: 1) in an amount of from about 1 to about 60% by weight of the total solids in the photosensitive composition, more preferably from about 5% to about 50%.

In the practice of the present invention, the colorant component is preferably present in an amount sufficient to uniformly color the uniform film. It is preferably present in an amount ranging from about 5 to about 50% based on the weight of the solids in the photosensitive composition. A more preferred range is from about 8 to about 40%.

A plasticizer may also be included to prevent coating brittleness and to keep the composition pliable if desired. Suitable plasticizers include dibutylphthalate, triarylphosphate and substituted analogs thereof and preferably dioctylphthalate.

The following nonlimiting examples serve to illustrate the invention.

Example 1

This example illustrates preparation of a resin of the present invention. Ten (10) parts of polyvinyl butyral resin (Mowital B 30T, Hoechst Celanese Corporation), consisting of polyvinyl acetal units: 69-71%, polyvinyl acetate units: 3%, polyvinyl alcohol units: 24-27%, were dissolved in 90 parts of dry methyl ethyl ketone. To the solution there were added 2 parts of methacryloyl isocyanate, and the solution was stirred overnight. IR revealed no presence of the isocyanate band after that time.

Example 2 This example illustrates preparation of a resin in another embodiment of the present invention. Ten (10) parts of polyvinyl formal resin (Formvar 12/85,

Monsanto), consisting of polyvinyl acetal units: 68% approximate, polyvinyl acetate units: 22-30%, polyvinyl alcohol units: 5.5-7%, were dissolved in 90 parts of dry THF. To the solution there were added 1.5 parts of isocyanatoethyl methacrylate, followed by 0.1 parts of dibutyltin dilaureate catalyst. The solution was left stirring overnight, after which time no isocyanate band was detectable by IR.

Example 3 This example illustrates preparation of a resin in another embodiment of the present invention. Ten (10) parts of polyvinyl propional resin (Hoechst Celanese Corporation), consisting of polyvinyl acetal units: 76.6%, polyvinyl acetate units: 13.6%, and polyvinyl alcohol units: 9.8%, were dissolved in 90 parts of dry methyl ethyl ketone. To the solution there were added 2 parts of isocyanatoethyl methacrylate, followed by 0.1 parts of dibutyltin dilaureate. The solution was left stirring overnight, after which time no isocyanate band was detectable by IR.

Example 4 This example illustrates preparation of a resin in another embodiment of the present invention. Ten (10) parts of polyvinyl butyral resin (Butvar B 79, Monsanto), consisting of polyvinyl acetal units: 88%, polyvinyl acetate units: 0- 1.5%, and polyvinyl alcohol units: 10.5-13%, were dissolved in 90 parts of dry n- butyl acetate. To the solution there were added 3 parts of isocyanatoethyl methacrylate, followed by 0.1 parts of dibutyltin dilaureate. The solution was left stirring overnight, after which time no isocyanate band was detectable by IR. Example 5 This example illustrates the difference in photosensitivity of the photopolymerizable composition containing the inventive resin vs. the unmodified resin as binder; both compositions containing equal amounts of monomer and photoinitiator.

Solution I (inventive resin). To the reaction mixture from Example 1 there were added 2 parts of a monomer (Sartomer 399, dipentaerythritol pentaacrylate), and 0.2 parts of a photoinitiator (2-stilbenyl-4,6-di(trichloromethyl)-s-triazine, SDTT). Solution II (comparison). Example 1 was repreated, only this time no methacryloyi isocyanate was added to the solution. Instead, 2 parts of Sartomer 399 and 0.2 g of photoinitiator (SDTT) were added to the solution.

Solutions I and II were drawn down into 3 mil polyester sheets (Melinex 505, ICI) using Meier rod #18 and dried in the oven. The photosensitive elements were then exposed for 2 minutes using a 5 kW metal halide lamp under a continuous-tone step wedge with a density range from 0.05 to 3.05 and density increments of 0.15.

They were then developed using ethanol, by gentle rubbing for 1 minute.

The photosensitive element containing inventive resin revealed that solid step 12 become insoluble in ethanol as a result of exposure, as opposed to step 2 of the comparison solution, indicating a very desireable increase of apparent photospeed as a result of modification of the polyvinyl acetal resin with methacryloyi isocyanate.

Example 6 This example illustrates the difference in photosensitivity of the photopolymerizable composition containing the inventive resin vs. the unmodified resin as binder; composition containing the unmodified resin containing twice as much monomer as the composition containing the inventive resin, and equal amount of photoinitiator.

Example 5 was repeated only this time Solution I contained 1 part of Sartomer 399, and Solution II contained 2 parts of Sartomer 399. Both solutions contained 0.2 parts of SDTT photoinitiator. Ethanol development revealed solid step 9 for composition containing inventive resin, vs. solid step 2 for the comparison composition.

The acceptable photospeed and lack of tack of the composition containing the inventive resin warrants its use without the protective polyvinyl alcohol top layer commonly used in photopolymerizable articles. On the other hand, the comparison composition is soft and more tacky and its photospeed is poor.

Example 7 This example illustrates the performance of the inventive resin vs. an unmodified resin in a peel-apart color proofing element. The peel-apart color proofing element is prepared in the following way:

On the untreated side of Hostaphan 4407 2 mil PET cover sheet, there was coated, using Meier Rod #12, the following color solution:

1. Tetrahydrofuran - 21.7 g

2. Dowanol PM - 43.42 g 3. Diacetone Alcohol - 16.18 g

4. Urethane adduct of 1 mol of trimethyl- hexamethylene diisocyanate with 2 moles of 2-hydroxyethyl-4,6-bis-acryloxyethyl isocyanurate (Aronix M-215, Mitsui Corp.) - 3.38 g 5. 2-biphenyl-4,6-bis-trichloromethyl-s-triazine- 0.84 g

6. Magenta Pigment Dispersion, consisting of 10.8 parts Permanent Carmine FBB pigment, 9 parts Formvar 12/85 resin, and 80.2 parts gamma- butyrolactone- 14.48 g After drying the color layer in the oven, the following photosensitive adhesive solution was overcoated on above color layer using Meier Road #24, and dried.

1. Reaction Mixture from Preparation Example 4 - 100 g

2. Sartomer 399 - 4 g

3. 2-biphenyl-4,6-bis-trichloromethyl-s-triazine - 1 g The above photosensitive element was laminated, using heat and pressure, to Pressmatch Commerical receiver base (available from Hoechst Celanese Corporation). It was then exposed to actinic radiation from 5 kW Hg lamp through the transparent cover sheet using a UGRA target for 15 seconds. Peel development resulted in the exposed areas of the color layer staying on the adhesive, while unexposed areas of the color layer being removed together with transparent cover sheet. The image resolution was 2-98% at 150 lines/inch.

The preparation of the above photosensitive element was repreated, only this time, instead of Reaction mixture from Example 4, an unmodified 10% Butvar B 79 solution in n-butyl acetate was used to prepare the photosensitive adhesive solution.

No image was obtained after 15 second expsoure and peel development.

Claims

WHAT IS CLAIMED:

1. A binder resin for photosensitive compositions, the binder comprising the units:

where: a = 50-99%, b = 1-50%, and where:

R, is hydrogen atom, a substituted or unsubstituted alkyl radical containing

1-6 carbon atoms, or a substituted or unsubstituted aryl radical R₂ is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms. 2. A photosensitive composition containing the resin of claim 1, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

3. The resin of claim 1, wherein R, is n-butyl and R₂ is

-Y— — C— C=CH₂

where Y is ethyl and Z is methyl.

4. A photosensitive composition containing the resin of claim 3, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

5. The resin of claim 1 comprising the units:

b)

where: a = 50-98% b = 1-50% c = 1-30% and a + b + c = 100% and where:

R, is hydrogen atom, a substituted or unsubstituted alkyl radical containing

1-6 carbon atoms, or a substituted or unsubstituted aryl radical

R₂ is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms, and R₃ is an alkyl radical containing 1-4 carbon atoms.

A photosensitive composition containing the resin of claim 5, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

The resin of claim 5, wherein R, is n-butyl and R₂ is

where Y is ethyl and Z is methyl. A photosensitive composition containing the resin of claim 7, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

9. The resin of claim 1 comprising the units:

where: a = 50-98% b = 1-50% d = 1-30% and a + b + d = 100% and where:

R, is hydrogen atom, a substituted or unsubstituted alkyl radical containing 1-6 carbon atoms, or a substituted or unsubstituted aryl radical R₂ is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms.

10. A photosensitive composition containing the resin of claim 9, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

11. The resin of claim 9, wherein R, is n-butyl and R₂ is

where Y is ethyl and Z is methyl.

12. A photosensitive composition containing the resin of claim 11, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

13. The resin of claim 1 comprising the units::

a)

where: a = 50-99% b = 1-30% c = 0-30% d = 0-50%, and a + b + c + d = 100% and where:

R, is hydrogen atom, a substituted or unsubstituted alkyl radical containing

1-6 carbon atoms, or a substituted or unsubstituted aryl radical R₂ is

where Z is hydrogen or methyl and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms, R₃ is an alkyl radical containing 1-4 carbon atoms.

14. A photosensitive composition containing the resin of claim 13, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

15. The resin of claim 13, wherein R_j is n-butyl and R₂ is

where Y is ethyl and Z is methyl.

16. A photosensitive composition containing the resin of claim 15, an ethylenically unsaturated polymerizable monomer, and a photoinitiator.

17. A method for producing a photosensitive element which comprises:

(A) providing a suitable substrate;

(B) providing a photosensitive mixture, which comprises an organic binder, an ethylenically unsaturated polymerizable monomer, and a photoinitiator, wherein the binder is present in sufficient amount to bind the components into a uniform film, wherein the photoinitiator is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image differentiation when the photosensitive mixture is imagewise exposed to actinic radiation wherein the organic binder comprises a resin comprising the units:

and d)

where a = 50-99%, b = 1-30%, c ^*= 0-30% d ^•= 0-50%, and a + b + c + d = 100%, and where

R_] is hydrogen, a substituted or unsubstituted alkyl containing

1-6 carbon atoms, or a substituted or unsubstituted aryl,

where Z is hydrogen or methyl, and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms, and R₃ is an alkyl radical containing 1-4 carbon atoms, (C) coating the photosensitive mixture on a suitable substrate

The process of claim 17, wherein R, is n-butyl and R₃ methyl and R₂ is

where Y is ethyl and Z is methyl

The process of claim 17 wherein the substrate is an aluminum sheet

The process of claim 17 wherein the substrate is a plastic or paper sheet

The process of claim 17 wherein the substrate is a polyester sheet

A photosensitive element which comprises (A) a suitable substrate;

(B) a photosensitive mixture, which comprises an organic binder, an ethylenically unsaturated polymerizable monomer, and a photoinitiator, wherein the binder is present in sufficient amount to bind the components into a uniform film, wherein the photoinitiator is present in sufficient amount to initiate polymerization of the polymerizable monomer, wherein the polymerizable monomer is present in sufficient amount to provide image differentiation when the photosensitive mixture is imagewise exposed to actinic radiation wherein the organic binder comprises a resin comprising the units:

R, is hydrogen, a substituted or unsubstituted alkyl containing

1-6 carbon atoms, or a substituted or unsubstituted aryl, R- is

where Z is hydrogen or methyl, and Y is a substituted or unsubstituted alkyl of 1-4 carbon atoms, and R₃ is an alkyl radical containing 1-4 carbon atoms; (C) the photosensitive mixture coated on the suitable substrate.

23. The photosensitive element of claim 22, wherein R, is n-butyl and R₃ methyl and R, is:

where Y is ethyl and Z is methyl. 24. The photosensitive element of claim 22 wherein the substrate is an aluminum sheet.

25. The photosensitive element of claim 22 wherein the substrate is a plastic or paper sheet.

26. The photosensitive element of claim 22 wherein the substrate is a polyester sheet.