DK145357B - Laminate for production of pressure plates or photo reserves - Google Patents

Abstract

Laminate for production of pressure plates or photo reserves of the type given in the introduction to claim 1. The invention thus concerns a laminate with a layer of light-sensitive mixture, which can easily be developed with the help of an alkaline aqueous solution for the production of a product, which can be used for pressure plates and photo etchings. These laminates are particularly useful for the production of pressurized circuits, because the reserves, which are produced on the base of these, are impermeable compared to conventional plating solutions.

Description

(19) DENMARK (w), \ R £ /

^ Π2) PRESENTATION WRITING od H5357 B

PATENT DIRECTORATE. AND THE TRADE BRAND

(21) Application No. 1 6/73 (51) IntCI.3 0 03 F 7/10 (22) Submission date 3 · Jan · 1973 (24) Running day 3 Feb. 1972 (41) Aim. available Jan 3 1973 (44) Presented 1. November 1 982 (86) International application no.

(86) International filing day (85) Continuation day - (62) Application No. 481/72

(30) Priority Feb 4 1971, 112797, US

(71) Applicant DYNACHEM CORPORATION, Santa Fe Springs, US.

(72) Inventor Michael Nicholas Gilano, US: Mel wine Alan Lipson, US: Richard Edmund Beaupre, US.

(74) Hofman-Bang & Bout ard engineering firm.

(54> Laminate for printing plate or photoresist = vague.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a laminate for the production of printing plates or photoreservers, of the kind specified in the preamble of claim 1. The invention thus relates to a laminate having a layer of photosensitive mixture which can be easily developed by an alkaline aqueous solution to produce a product D useful for printing plates and photoreservs. These laminates are particularly useful for the production of printed circuits because the reservoirs made therefrom are

.ISLAND

f. are impermeable to conventional plating solutions.

r— *

D

145357 2

It has long been recognized the desirability of being able to form laminates with photosensitive layers which can be developed without the necessity of the conventional organic solvents. Organic solvents are expensive and risky in terms of toxicity and flammability and they pollute air and water.

The benefits of such aqueous systems were noted as early as 1956 in connection with U.S. Patent No. 2,760,863; however, no specific mixture was described and it can be assumed that the patent owner was unable to find any satisfactory mixture. Other references to such water-soluble mixtures are found in U.S. Pat.

No. 2,927,022 and 2,893,868. Regardless of the technical advantages of the compositions disclosed in these patents, it is clear that such mixtures, to the extent that they could be developed with aqueous, alkaline solutions, were not were sufficiently insoluble on the exposed parts or were also capable of being attacked by the conventional plating and by etching solutions in which the photoreserv was used for a printed circuit.

In connection with the laminate according to the invention, which is of the kind specified in the preamble of claim 1, it has now been found that, subject to the precautions specified in the characterizing part of claim 1, photopolymerizable layers can be prepared on the basis of photopolymerizable mixtures. which can be developed with aqueous alkaline solutions. In addition, the exposed portions of these mixtures have excellent resistance to alkaline solutions, including the alkaline etching agents and the alkaline plating solutions that frequently occur during the manufacture of printed circuits and chemically processed parts.

145357 3

The advantages of the laminate according to the invention are obtained by selecting, in connection with the photopolymerizable layer, a preformed, compatible, macromolecular polymeric binder which is a copolymer of (1) a monomer of a non-acidic vinyl monomer and (2) an unsaturated, carboxyl group-containing monomer, wherein the components (1) and (2) are subject to the restrictions set out in claim 1. The use of the mixture described herein completely eliminates the need for organic solvents and provides a highly solvent resistant reservoir.

It is admittedly known from GB patent specification No. 1 188 921 a laminate containing a copper support, a photopolymerizable layer of the kind specified in the preamble of claim 1, and a cover layer impermeable to oxygen. However, this patent is limited to a category of photopolymerizable materials in which the polymeric binder contains a protruding, water-soluble salt group, cf. page 2 of the patent, lines 13-18. The laminates described in the English patent are not well suited as photo reservoirs for printed circuits and chemical etching because they are unstable and are easily attacked by etching and plating solutions. Furthermore, it is apparent from the English patent that all the compositions produced contain a monofunctional salt as one of the polymerizable materials. This salt is formed immediately by mixing the constituents of the mixture and before polymerization. In addition, the sole purpose of manufacturing the reservoir in English Patent No. 1,188,921 is to produce printing plates. The photopolymer serves solely as a black receptor and therefore it is not necessary for it to withstand alkali and acid treatment. In addition, the protective layer shown in the English patent is a very thin layer that cannot be peeled by mechanical means, cf. the section of the patent linking page 2 to page 3. In contrast, the protective layer must in the laminate according to the invention could be peeled by mechanical means and be self-supporting.

145357 4

For this purpose, the dry photopolymerizable layer can be covered with polyethylene film on one surface and with a film of polyethylene terephthalate on the other, noting that both of these are peeled off during the photoreser wave preparation.

In addition, the photopolymerizable layer may contain suitable dyes and pigments and other additives, such as plasticizers and adhesion promoters, which may be necessary to improve the physical and chemical properties of the photopolymerizable layer.

The ethylenically unsaturated compound must contain at least two terminal ethylenic groups (CH2 = C <) and have a boiling point above 100 ° C under atmospheric pressure and be capable of forming a high molecular weight polymer by a photoinitiated, chain transferring addition polymerization, making use of free radicals.

Such compounds are described in U.S. Patent No. 2,760,863.

Suitable compounds which may be used alone or in combination include an alkylene or a polyalkylene glycol diacrylate prepared from the alkylene glycols containing 2 to 15 carbon atoms or the polyalkylene ether glycols containing 1 to 10 ether linkages.

Due to the generally rapid insolubility rate of the materials upon exposure, probably arising from a relatively rapid establishment of a polymeric network structure, a prominent category of the low molecular weight addition polymerizable constituents are those having a greater number of addition polymerizable ethylenic bonds. especially when in the form of terminal bonds, and especially those in which at least one and preferably most of such bonds are conjugated to a double bonded carbon atom, including carbon double bonded to carbon and to such heteroatoms as nitrogen, oxygen and sulfur. In particular, such materials in which the ethylenically unsaturated groups, especially the vinylidene groups, are conjugated with ester or amide structures, should be highlighted. According to the invention, as mentioned, unsaturated esters of polyols are used, in particular such esters of the methylene carboxylic acids, for example ethylene diacrylate, diethylene glycol diacrylate, glycerol diacrylate, glycerol triacrylate, ethylene dimethacrylate, 1,3-propylene dimethacrylate, 1,2,4-butanethriol, 1,2,4-butanethriol. acrylate, pentaerythritol tetramethacrylate, 1,3-propanediol diacrylate, 1,5-pentadiol dimethacrylate, the bis acrylates and methacrylates of polyethylene glycols of molecular weight 200-500, unsaturated amides, especially of the methylene carboxylic acids, and especially of alpha oxygen and omega omega diamines such as methylene bisacrylamide, methylene bis methacrylamide, 1,6-hexamethylene bis acrylamide, diethylenetriamine tris-methacrylamide, bis- (methacrylamidopropoxy) -ethane, B-methacrylamidoethyl methacrylate, N- (B- hydroxyethyl) oxyethyl acrylamide and vinyl esters such as divinyl succinate, divinyl adipate, divinyl phthalate, divinyl terephthalate, divinylbenzene-1,3-disulfonate and divinylbutane-1,4-disulfone to.

The preferred monomeric compounds are the di- and polyfunctional ones, but monofunctional monomers can also be used. The amount of monomer added varies with the particular thermoplastic polymer. J '

The component of the styrene type of the polymeric binder in the photopolymerizable layer of the laminate of the invention has the general formula: R-C = CH 2 O where R is hydrogen or an alkyl group having between 1 and 6 carbon atoms or a halogen atom.

The non-acidic vinyl monomer component of the polymeric binder in the photopolymerizable layer of the laminate of the invention "has the general formula:

CH "= C-Y

Z | /

X

wherein the symbols have the meaning given in the characterizing part of claim 1.

Examples of these vinyl monomers are vinyl acetate, vinyl butyrate, vinyl benzoate, vinyl chloride, methyl acrylate, acrylonitrile, alkyl-substituted acrylamides, vinyl methyl ketone, vinyl propyl ketone, vinyl methyl ether, vinyl ethyl ether and vinyl hexyl ether.

The second comonomer in the photopolymerizable layer in the laminate of the invention is one or more unsaturated carboxyl group-containing monomers having from 3 to 15 carbon atoms, but preferably from 3 to 6 carbon atoms. The most preferred compounds are acrylic acid and methacrylic acid. Other acids which may be used are cinnamic acid, crotonic acid, sorbic acid, itaconic acid, propiolic acid, maleic acid and fumaric acid, or the corresponding half-esters thereof or - where possible - the corresponding anhydride.

The ratio of the styrene or vinyl component to the acidic comonomer in the photopolymerizable layer of the laminate of the invention is chosen such that the copolymer is soluble in the 2% aqueous solution of trisodium phosphate. If the amount of the styrene or vinyl monomer is too high, the unexposed portion will not be sufficiently soluble; on the other hand, if the amount of the styrene or vinyl monomer is too low, the exposed area will be sticky, swollen or dissolved in the 2% aqueous solution of trisodium phosphate. As a convenient criterion, the copolymer serving as a binder should be such that a 40% solution in ketones or alcohols will have a viscosity of from 10G to 50,000 cP.

Representative comonomer ratios in the polymeric binder are between 70:30 and 85:15 for styrene-acrylic acid or methacrylic acid, between 35:65 and 70:30 for styrene-monobutyl maleate, and between 70:30 and 95: 5 for vinyl acetate-crotonic acid. The degree of polymerization of the copolymer serving as a binder is such that the binder forms a non-sticky continuous film after exposure and development. Essentially, the molecular weight is between 1000 and 500,000. The ranges of the copolymer ratios and the degree of polymerization of the particular binders can be readily determined by examining the solubility in the dilute alkaline solution of representative polymers. This represents a molecular weight of from approx. 1000 to 500,000.

As stated, the reservoir is made from the laminate of the invention resistant to the usual plating and etching solutions. Most surprising is its resistance to the copper pyrophosphate used in pattern plating, which represents an extremely high alkalinity. Other solutions that leave the reservoir unaffected include ferric chloride, ammonium persulfate and chromic sulfuric acid.

The photoinitiators used in the foot-polymerizable layer 1 laminate of the invention are preferably those which are activatable with actinic light and thermally inactive at 185 ° C or below. These include the substituted or unsubstituted polynuclear quinones, 9,10-anthraquinone, 1-chloranthraquinone, 2-chloranthraquinone, 2-methylanthranquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,4-naph 10-phenanthrenquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dichloronaphthoquinone, 1,4-dimethylanthraquinone, 2,3-dimethylanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone sodium salt of anthraquinone-alpha-sulfonic acid, 3-chloro-2-methyl-anthraquinone, retenquinone, 7,8,9,10-tetrahydronaphthacenquinone and 1,2,3,4-tetrahydrobenz (a) anthracene-7 , 11-dione.

The following photoinitiator described in U.S.A. patent no.

2,760,863, and some of which may be thermally active at temperatures as low as 85 ° C, may also be used: vicinal ketaldonyl compounds such as diacetyl and benzil, alpha-ketal dicyl alcohols such as alpha-methylbenzoin, alpha allyl benzoin and alpha-phenylbenzoin.

Silver persulfate is also useful as an initiator which forms free radicals and which can be activated by actinic radiation.

Certain aromatic ketones, for example benzophenone and 4,4'-bis-dialkylaminobenzophenones, are also useful.

The photopolymerizable layer of the invention laminate also contains thermal polymerization inhibitors. These include p-methoxyphenol, hydroquinone and alkyl and aryl substituted hydroquinones and quinones, tert-butyl catechol, pyrogallol, copper resinate, naphthylamines, beta-naphthol, cuprochloride, 2,6-di-tert.-butyl-p-cresol, 2 2-methylene-bis- (4-ethyl-6-t.-butylphenol), phenothiazine, pyridine, nitrobenzene, dinitrobenzene, p-toluquinone, chloranil, aryl phosphates and arylalkylphosphites.

If desired, the photopolymerizable layer of the laminate of the invention may contain dyes and pigments. Appropriate staining agents will be compatible with the photosensitive mixtures and will not interfere to a greater extent with the photosensitivity of the mixture. The following specific compounds serve as illustrations: Fuchsin (CI 42510), auramine base (CI 4100B), calcoid green S (CI 44090), Para Magenta (CI 42500), trypasone (CI 42505), new magenta (CI 42520), acid violet RRH (CI 42425), red violet 5RS (CI 42690), nil blue 2B (CI 51185), new methylene blue GG (CI 51195), CI basic blue 20 (C.I.

42585), iodine green (C.I. 42556), night green B (C.I. 42115), C.I. direct yellow 9 (C.I. 19540), C.I. acid yellow 17 (C.I. 18965), C.I. acidic yellow 29 (CI 18900), tartrazine (CI 19140), supra-mixed yellow G (CI 19300), buffalo variety 10B (CI 27790), naphtha lens variety 12B (CI 20350), solid black L (CI 51215), ethyl violet (CI 42600), Pontacyl wool blue BL (CI 50315), Pontacyl wool blue GL (CI 52320) (the figures are from the second edition of the Color Index).

The laminate with the photopolymerizable layer is exposed to a source of actinic radiation. This can be done through a halftone image or a process slide, for example a process negative or positive, a stencil or a mask. Exposure can also be performed through a negative or positive image with a continuous tone. Exposure can be made by the contact or projection method, with or without a cover plate over the photopolymerizable layer or by projection using a cover layer. These methods are known by experts.

Since free-radical addition polymerization inhibitors, which are activatable by actinic radiation, usually exhibit their maximum sensitivity in the ultraviolet region, the radiation source should provide an effective amount of this radiation. Both sources that produce point radiation and broad-spectrum radiation are effective. Such sources include carbon arcs, mercury vapor arcs, fluorescent phosphor emitting fluorescent lamps by ultraviolet radiation, argon incandescent lamps, electronic flashlights and photographic floodlights.

Among these, the mercury vapor lamps, especially the high mountain sun, are most suitable. Under certain circumstances it may be advantageous to expose with visible light using a photoinitiator sensitive in the visible range of the spectrum, for example 9,10-phenanthrenguinone. In such cases, the radiation source should provide an effective amount of visible radiation. Many of the sources of radiation mentioned above provide the required amount of visible light.

The photopolymerizable mixtures may be induced upon exposure, for example, by dynamic action of rays by immersion under agitation, by brushing or scrubbing to desired aqueous base images, i.e. aqueous solutions of water-soluble bases at concentrations generally in the range of 0.01 to 10% by weight.

Suitable bases for the development include the alkali metal hydroxides, for example, lithium, sodium and potassium hydroxide, the basic reacting alkali metal salts of weak acids, e.g. .

1 x 10, for example, primary amines such as benzyl, butyl and allylamines, secondary amines, for example, dimethylamine and benzylmethylamine, tertiary amines, for example trimethylamine and triethylamine, primary, secondary and tertiary hydroxyamines, e.g. diethanol and triethanolamines, 145357 and 2-amino-2-hydroxymethyl-1,3-propanediol, cyclic amines, for example morpholine, piperidine, piperazine and pyridine, polyamines such as hydrazine, ethylene and hexamethyleneamines, the water soluble basic salts, for example, the carbonates and bicarbonates of the above-mentioned amines, ammonium hydroxide and tetra-substituted ammonium hydroxides, for example tetramethyl, tetraethyl, trimethylbenzyl, and trimethylphenylammonium hydroxides, sulfonium hydroxides, for example trimethylsulfonyl, diethyl the basic soluble salts thereof, for example, the carbonates, bicarbonates and sulfides, alkali metal phosphates and pyrophosphates, for eczema pel sodium and potassium triphosphates and sodium and potassium pyrophosphates, tetrasubstituted (preferably exclusively alkyl) phosphonium, arsonium and stibonium hydroxide, for example tetramethylphosphonium hydroxide.

The photopolymerized layer of the laminate of the invention can generally be removed by immersion in heated aqueous solutions of strong alkaline substances or, if desired, in removal compositions known to those skilled in the art.

The following examples are intended to illustrate the laminate of the invention, including its manufacture and use.

EXAMPLE 1

The solution given below was applied by coating to a polyester film having a thickness of 0.0025 cm and dried in air. The dry thickness of the sensitized layer was approx. 0.0025 cm. The dried layer was covered with a polyethylene film whose thickness was 0.0025 cm.

Copolymer of 37% styrene and 63% monobutyl maleate, average molecular weight 20,000, viscosity of 10% aqueous solution of ammonium salt = 150 cP 67.0 g

Trimethylol propane triacrylate 22.0 g

Tetraethylene glycol diacrylate 11.0 g n 1A5357

Benzophenone 2.3 g 4,4'-bis- (dimethylamino) -benzophenone 0.3 g 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol) 0.1 g

Methyl violet 2B base 0.7 g

Benzotriazole 0.20 g

Methylethyl ketone 140.0 g

A piece of a copper-clad epoxy fiberglass sheet was cleaned by scrubbing with an abrasive cleanser, swab, and thorough rinsing in water. It was then immersed for 20 seconds in a dilute hydrochloric acid solution (2 volumes of water plus 1 volume of concentrated hydrochloric acid), a secondary rinse with water and then a drying of air jets.

The polyethylene cover film was removed from a section of the photopolymerizable element available as a sandwich assembly. The exposed reservoir coating with its polyester backing was laminated to the pure copper with the surface of the photopolymerizable layer in contact with the copper surface. The lamination was carried out by rubber-coated rollers operating at 121 ° C under pressure of 0.54 kg / l. linear cm at the constriction and at a rate of 0.61 m per. minute. The resulting sensitized copper-coated plate, protected in the manner indicated by the polyester film, could be stored for later use if necessary. In this case, it was exposed to light through a high contrast image, in which the conductive pattern appeared as transparent areas on an opaque background. The exposure was accomplished by arranging the sensitized copper-clad plate (with its polyester film still intact) and the slide in a photographic print frame. Exposure was performed for 45 seconds with a 400 Watt, 50 Amp mercury vapor lamp at a distance of 30.5 cm. The support polyethylene terephthalate film was peeled off and the exposed reservoir layer was developed by stirring the plate with stirring in a trough containing 2% sodium carbonate in water for 3.5 minutes followed by a rinse with water. The resulting plate contained a dried reservoir pattern of the clear areas of the exposure slide.

The plate was now etched with a 45 ° Baumé solution of ferric chloride and then rinsed and dried. The reserve was removed from the residual end copper by immersing for 2 minutes in a 3% solution of sodium hydroxide in water at 70 ° C. The result was a high quality plate with a printed circuit board.

EXAMPLE 2

The following solution was applied by coating a 0.0025 cm thick polyester film and allowing it to dry under ambient conditions for 30 minutes.

Copolymer of 75% styrene and 25% methacrylic acid, viscosity of a 40% solution in methyl ethyl ketone is 10 360 cP 11.0 g trimethylol propane triacrylate 4.66 g

Tetraethylene glycol diacrylate 2.33 g

Benzophenone 0.75 g of 4,4 'bis (dimethylamino) benzophenone 0.10 g of 2,2'-methylene bis (4-ethyl-6-tert.-butylphenol) 0.3 g

Methyl violet 2B base 0.2 g

Benzotriazole 0.07 g

Methyl ethyl ketone 30.0 g

The dry thickness of the sensitized layer was approx. 0.0034 cm. The coated material was then laminated to a cleaned, copper-clad plate as in Example 1. Exposure was made through a slide containing an opaque pattern of known area for 1.5 minutes with an exposure unit as described in Example 1. The polyester support film was peeled off and the exposed reservoir layer was developed by stirring the plate in a trough containing 2% trisodium phosphate in water for 2 minutes followed by rinsing with water.

The exposed copper surface was further cleaned after developing by dipping the plate in a bath of 20% ammonium persulfate for 30 seconds, washing with copious amounts of water, dipping for 30 seconds in a 20% solution of hydrochloric acid and water. Rinse with water and then wipe the plate with air streams. The purified plate was then plated for 45 minutes at 0.032 Amp. cm in a copper pyrophosphate plating bath at 55 ° C.

EXAMPLE 3

A copper-coated piece of an epoxy fiberglass plate was cleaned as described in Example 1. The cleaned, dried plate was sensitized by allowing the following solution to flow over the surface of the plate:

Copolymer of 37% styrene and 63% monobutyl maleate, average molecular weight 20,000, viscosity of 10% aqueous solution of ammonium salt = 150 cP 40.0 g

Pentaerythritol tetraacrylate 23.0 g

Benzophenone 1.5 g 4,4 'bis (dimethylamino) benzophenone 0.2 g 2,2'-methylene bis- (4-ethyl-6-tert-butylphenol) 0.6 g

Methyl violet 2B base 0.4 g

Methylethyl ketone 100.0 g

Benzotriazole 0.15 g

The dry thickness of the sensitized layer was approx. 0.0025 cm. A copper-coated plate was prepared, the reservoir coating was laminated thereto, and the resulting element was exposed exactly as in Example 1. The supporting film was peeled off and the exposed reserve layer was developed by keeping the plate stirred for a period of time. a trough containing 2% trisodium phosphate for 2 minutes followed by a rinse with water. The plate was now etched as in Example 1 to form a high quality plate with a printed circuit.

EXAMPLE · 4 The following solution is coated on a 0.025 mm thick polyester film and air dried:

Copolymer of 95% vinyl acetate and 5% crotonic acid, average molecular weight 90,000, viscosity of 8.6% solution of ethyl alcohol between 13 and 18 cP 70.0 g

Pentaerythritol tetraacrylate 30.0

Benzophenone 2.3 g 4,4'-bis (dimethylamino) benzophenone 0.3 g 2.2, methyl bis (4-ethyl-6-tert-butylphenol) 0.1 g

Methyl violet 2B base 0.07 g

Benzotriazole 0.20 g

Methylethyl ketone 150.0 g

The thickness of the photosensitive layer after drying is 0.025 mm. A plate with a copper coating is prepared and then the treated polyester film is adhered, then the laminate is exposed as set forth in Example 1. The carrier film is peeled off and the exposed coating layer is developed by moving the plate in a bowl containing 2% trisodium phosphate for 2 minutes, then the plate rinse in water.

The plate is then etched as set forth in Example 1 to obtain a high quality printed circuitless.

EXAMPLE 5

The photosensitive solution described in Example 1 is coated on copper printing pads. After drying in hot air to a dry thickness of approx. 0.0025 cm, the photosensitive layer is coated with a dilute aqueous solution of polyvinyl alcohol and re-dried with warm air. The water-soluble polymer forms a thin, protective barrier to oxygen.

This pre-sensitized metal plate can be stored for extended periods of time.

By exposure to actinic light through a suitable photographic negative, the unexposed, photosensitive layer and the water-soluble upper coating can be produced simultaneously, leaving the metal plate ready for etching. The photopolymerized automotive conductor area then serves as an excellent reservoir for the deep-bead processes normally used in the manufacture of metal printing plates. These resulting products are resistant to common etching agents, e.g. ferric chloride and nitric acid, film forming agents and forming agents usually added to the etching mixture to check the etching geometry.

EXAMPLE 6

The procedure of Example 5 is followed, except that a 0.0025 cm thick polyester film is used as a protective layer instead of a water-soluble polymer.

After exposure to actinic light, the protective layer is peeled off before being developed in an aqueous, alkaline solution. As in Example 5, the photopolymerized image area serves as an excellent reservoir for the deep staining of printing plates.

EXAMPLE 7

The photosensitive solution described in Example 1 is applied by coating a 0.0025 cm thick polyester film, drying in air and covered with a 0.0025 cm thick polyethylene film. This three-layer, sandwich-like film assembly can be stored in sheets or rolls in light-tight areas for an unlimited amount of time. Prior to use, the polyethylene covering film is peeled off and the photosensitive layer is contacted with a copper plate of the type described in Example 5 and a support is provided by lamination. Upon exposure to actinic light, the protective polyester layer is peeled off and the development is carried out in an aqueous alkaline solution. As in Example 5, the photopolymerized image area is an excellent reservoir for the deep staining of printing plates.

Claims (5)

17 146357 1. Laminate for the production of printing plates or photoresist sheets and of the kind in which a metallic copper or copper alloy layer is coated with a photopolymerizable layer of (A) an addition polymerizable material consisting essentially of one or more non-polymeric materials. gaseous compounds exhibiting a boiling point above 100 ° C under atmospheric pressure and containing at least two terminal ethylenic groups and which is an unsaturated ester of a polyol, an unsaturated amide or a vinyl ester, (B) a photoinitiable initiator system forming free radicals, (C) an inhibitor for thermal addition polymerization, and (D) a preformed macromolecular polymeric binder, wherein the photopolymerizable layer is optionally provided with a cover impermeable to oxygen, characterized in that the photopolymerizable layer contains : (A) from 10 to 60 parts by weight of the addition polymerizable material consisting essentially of one or more non-gaseous compounds which exhibits a boiling point above 100 ° C under atmospheric pressure containing at least two terminal ethylenic groups and which is an unsaturated ester of a polyol, an unsaturated amide or a vinyl ester; (B) from 0.001 to 10 parts by weight of the free-radical photoinitiable initiator system; (C) from 0.001 to 5 parts by weight of the thermal addition polymerization inhibitor; and (D) from 40 to 90 parts by weight of the preformed macromolecular polymeric binder which is a copolymer of: a primary monomeric material containing one or more non-acidic vinyl compounds selected from those which has the general formula: δ: Η2 or CH2 = cy X, where R is hydrogen, an alkyl group having from 1 to 6 carbon atoms or a halogen atom and where X is hydrogen and Y is OOCR1, OR1, OCR1, COOR1 , CN, CH = CH 2, 0 CNR 1 R 2 or Cl; or where X is methyl and Y is COOR1, CN, CH = CH20 O 34 or CNR R; or where X is chlorine and Y is Cl; and where R is an alkyl group having from 1 to 12 carbon atoms, a phenyl group 34 or a benzyl group and wherein R and R, which may be the same or different, are hydrogen, an alkyl group having from 1 to 12 carbon atoms or a benzyl group, and a secondary monomeric material consisting essentially of one or more alpha, beta-unsaturated carboxyl-containing monomers containing between 3 and 15 carbon atoms, whereby the ratio of the primary monomeric material to the secondary monomeric material is sufficient to render the binder soluble in a 2% aqueous solution of trisodium phosphate, whereby in the mixture there is no additional polymerizable material other than that identified as component (A). Laminate according to claim 1, characterized in that the polymeric binder in the photopolymerizable layer is a copolymer of styrene and an unsaturated carboxyl group-containing monomer. Laminate according to claim 1, characterized in that the polymeric binder in the photopolymerizable layer contains a copolymer of methacrylic acid as the secondary monomeric material. Laminate according to claim 1, characterized in that the polymeric binder in the photopolymerizable layer contains a copolymer of acrylic acid as the secondary monomeric material. Laminate according to claim 1, characterized in that the polymeric binder in the photopolymerizable layer contains