DE9016662U1 - Light-curable elastomeric mixture and recording material obtained therefrom for the production of relief printing plates - Google Patents

Description

HOECHST AKTIENGESELLSCHAFT - WORKS - ALBERT

90/K067G - 1 - 6. December 1990

WLK-Dr.P.-Wf

Light-curable elastomeric mixture and recording material obtained therefrom for the production of relief printing plates

The innovation concerns a light-curable, negative-working mixture and a recording material obtainable from it, which is suitable for the production of elastic relief printing plates.

Light-curable elastomer mixtures are known and usually contain an elastomer binder, a radically polymerizable compound and a polymerization initiator that can be activated by actinic radiation. Printing plates with a light-sensitive layer made of such a mixture are described, for example, in DE-A 22 15 090 (= GB-A 1 366 769). However, after exposure, they can only be cured with organic solvents.

20 Develop relief image.

In the patents DE-A 30 03 011 (= ZA 80/506), EP-A 0 130 828, DE-A 27 25 730 (= US-A 4 042 386) and DE-A 33 22 994 (= US-A 4 554 240) recording materials that can be developed in water and contain water-soluble polymers, in particular partially or completely saponified polyvinyl acetates, as binders are disclosed. However, the water resistance of the relief printing plates produced from them is low, so that use with water-dilutable printing inks is not possible.

In the light-sensitive mixtures according to DE-A 30 12 841 (= US-A 4 272 608) carboxylated butane

HOECHST AKTIENGESELLSCHAFT - KALLE-ALBERT PLANT

diene/acrylonitrile copolymers in which at least 25 % of the carboxy groups are neutralized with a metal cation of groups HA or HB of the periodic table, as binders.
5

Butadiene/styrene, isoprene/styrene and butadiene/acrylonitrile copolymers modified by reaction with 3-mercaptopropionic acid and thus containing carboxyl groups, as well as polybutadienes and polyisoprenes modified in the same way, are disclosed in US-A 4,446,220 as binders in light-sensitive compositions.

Rubber-elastic copolymers containing carboxyl groups, which are formed by copolymerization of 1,3-butadiene with (meth)acrylic acid, a polyethylenically unsaturated compound such as ethylene glycol dimethacrylate or divinylbenzene, and a monoethylenically unsaturated compound such as ethyl acrylate, are described in EP-A 0 277 418 and 0 261 910. The copolymers mentioned are used as binders in light-sensitive compositions.

A light-sensitive elastomer composition for flexographic printing plates, which contains a high molecular weight carboxylated butadiene/acrylonitrile copolymer as a binder, is mentioned in US-A 4 517 279.

The composition disclosed in GB-A 2 179 3 60 contains, in addition to the carboxylated butadiene/alkyl nitrile copolymer, a chlorosulfonated poly-

HOECHST AKTIENGESELLSCHAFT - WE&K; KALLE-ALBERT,

ethylene and can also be developed with an aqueous developer.

According to EP-A 0 183 552, 1,3-butadiene/methacrylic acid, 1,3-butadiene/methacrylic acid/acrylonitrile or butadiene/methacrylic acid/styrene copolymers are used as carboxyl group-containing binders.

The light-sensitive composition according to EP-A 0 251 228 contains a rubber-elastic binder with a glass transition temperature of less than -10 °C. Examples of such a binder are also copolymers containing carboxyl groups, such as 1,3-butadiene/(meth)acrylic acid/acrylic acid ester copolymers. The flexographic printing plates produced with this composition can be developed in water.

0 EP-A 0 273 393 describes chlorine-containing polymers with a glass transition temperature of less than +5 °C as binders in light-sensitive compositions for flexographic printing plates.

If the proportion of carboxyl groups in the polymeric binders is too low, the flexographic layer is difficult to develop with aqueous developers. In these cases, it is necessary to add a high proportion of polar monomers or auxiliary substances to the light-sensitive composition, which in turn result in a high cold flow of the unexposed material. "Cold flow" refers to plastic flow over a long period of time as a result of the dead weight, internal

HOECHST AKTIENGESELLSCHAFT - WEiIK KALLE-ALSERT

-A-

Material tensions or external stress. An increase in the carboxyl group content results in improved aqueous developability, but at the same time the guinea-elastic properties deteriorate and, in addition, the resistance to water-based printing inks is reduced.

The aim of the innovation was therefore to develop light-sensitive, elastomeric mixtures that produce light-sensitive layers without the previous disadvantages for the production of relief printing plates. After exposure or irradiation, these layers should be able to be developed in water under mild conditions and should also have a high resistance to water-based

15 dilutable printing inks.

Surprisingly, this problem could now be solved by using amphiphilic elastomer block copolymers as binders. "Amphiphilic" block copolymers are those block copolymers that have both water-attracting (hydrophilic) and water-repellent (hydrophobic) sections and therefore have surfactant characteristics.

The subject of the innovation is therefore a light-curable elastomer mixture, which contains as essential components

(a) an amphiphilic elastomeric binder or a mixture of such binders,

b) a radically polymerizable compound compatible with the binder with at least one terminal ethylenically unsaturated

HOECHST AKTIENGESELLSCHAFT - WORK' KALLE- ALBERT

Group and a boiling point at normal pressure above 100 ⁰ C and

(c) a compound or combination of compounds capable of initiating polymerisation of compound (b) under the action of actinic light,

contains.

The degree of surface activity can be easily adjusted by choosing the right pH value: At a high pH value, the carboxy groups are largely in deprotonated form, which results in a higher polarity and, accordingly, a stronger surface activity.

The mixture according to the innovation is characterized in that it contains as a binder an elastomeric block copolymer of the general structure AB, CAB, CACB, A _n XB _n , (AB) _n X, C _n X(AB) _n , (CA) _n XB _n , (CAB) _n X, C _n X(ACB) _n , (CA) _n X(CB) _n , (CAC) _n XB _n and (CACB) _n X. Furthermore, symmetrical BAB and BCACB block copolymers and branched representatives corresponding to X(BAB) _n X, B _n XA _n XB _n , X(BCACB) _n X, (BC) _n XA _n X(CB) _n and (B _n X(CAC) _n XB _n can be used as binders. In these block copolymers,

3 0 sowing stands

A for hydrophobic soft blocks with a glass transition temperature T_ of less than -30 ⁰ C,

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B for hydrophilic hard blocks containing acidic groups, preferably carboxy groups, and having a glass transition temperature _Δσ of more than +30 °C,

C for hydrophobic hard blocks (T > +50 "C),
X represents a unit formed from a compound having two or more vinyl or isopropenyl groups or a homopolymer block formed from such compounds, which is usually branched or cross-linked, and

η for the numerical ratio of A/B/C homopolymer blocks to the unit or to the homopolymer block X.

Suitable monomers for the block polymers A are conjugated dienes such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-3-ethyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-methyl-3-ethyl-1,3-pentadiene, 2-ethyl-1,3-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene, 3,4-dimethyl-1,3-hexadiene and 2-phenyl-1,3-butadiene. The use of mixtures of suitable dienes or the application of other anionically polymerizable conjugated dienes with 4 to 12 carbon atoms are also possible. Isoprene and 1,3-butadiene are preferred.

The block polymers B preferably result from α,β-ethylenically unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, acrylic acid, 0 methacrylic acid and crotonic acid. Other carboxylic acids with reduced electron density vinyl units, such as vinylbenzoic acid, can also serve as starting materials.

HOECHST AKTIENGESELLSCHAFT - KALLE PLANT--ALBERT·

Suitable starting materials for block polymers C are vinylaromatics, in particular styrene, alkylstyrene or vinylnaphthalene, with styrene being particularly preferred.
5

The units or blocks X are introduced by reacting the anionic chain end members with compounds that contain at least two vinyl or isopropenyl groups. Di- and trivinylbenzene as well as compounds with at least two methacryloyloxy groups are advantageously used. Particularly preferred are 1,4-divinylbenzene, 1,3-diisopropenylbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate.

Detailed information on the block copolymers can be found in the German patent application P 40 32 237.8, which has the same priority.

0 The molecular weights determined by gel permeation chromatography (GPC) range between 2,000 g/mol and 2,000,000 g/mol, preferably between 15,000 g/mol and 200,000 g/mol. The mass fractions of the block components involved vary from 20 to 99% for A, 1 to 30% for B and 0 to 79% for C.

The light-sensitive mixtures according to the invention generally contain 20 to 95% by weight, preferably 30 to 90% by weight of the amphiphilic binder either exclusively or in combination with other polymeric materials. Such polymeric materials can be chlorinated or chlorosulfonated polyethylene compounds, randomly structured or

HOECHST AKTIENGESELLSCHAFT - WEiRK KALLE-ALBERT

segmented diene polymers or copolymers as well as suitable thermoplastic elastomers that can be produced by polyaddition or polycondensation. They also contain at least one radically polymerizable olefinically unsaturated compound and at least one photoinitiator.

Suitable monomers with one or more polymerizable olefinic double bonds are in particular esters and amides of acrylic, methacrylic, fumaric and maleic acid as well as mixtures of these compounds. In addition, the alcohols or amines required for ester or amide formation can have further functionalities, such as ether units, hydroxy, primary, secondary.

or tert. amino groups. Examples of alcohols suitable for ester formation are open-chain and cyclic alkanols, such as butanol, hexanol, octanol, decanol, dodecanol, octadecanol, 2-ethylhexanol, cyclohexanol or borneol, but also oligo- or polybutadienes containing hydroxy groups and oligo- or polyisoprenes containing hydroxy groups. Other suitable alcohols are alkanediols, polyfunctional alcohols and similar compounds, e.g. 1,4-butanediol or 1,6-hexanediol, (poly)ethylene glycol or (poly)propylene glycol, glycerin, trimethylolpropane, butanetriol, pentaerythritol and others. The di- or polyfunctional alcohols can be partially or fully esterified. Other examples of unsaturated compounds are special esters and amides of (meth)acrylic acid, such as e.g. B. Dimethylaminoethyl(meth)acrylate, Dimethylaminopropyl(meth)acrylamide, 2-butylaminoethyl(meth)acrylate, ethylenebis(meth)acrylamide, Hexamethylenebis(meth)acrylamide, diethylenetriaminetris(meth)acrylamide, hydroxymethyl-

HOECHST AKTIENGESELLSCHAFT - ICALLE-ALBERT PLANT

(meth)acrylamide and bis-hydroxyethyl(meth)acrylamide. The amount of monomers is generally about 5 to 70% by weight, preferably about 10 to 50% by weight of the non-volatile components of the mixture.
5

Known compounds that have sufficient thermal stability during processing of the recording materials and sufficient radical formation upon exposure to initiate the polymerization of the monomers are suitable as photoinitiators for the mixtures according to the innovation. They should absorb light in the wavelength range of approx. 250 nm to 500 nm to form radicals. Examples of suitable photoinitiators are acyloins and their derivatives such as benzoin, benzoin alkyl ethers, 1,2-diketones and their derivatives, e.g. B. benzil, benzil acetals such as benzil dimethyl ketal, fluorenones, thioxanthones, polynuclear quinones, acridines and quinoxalines, also trichloromethyl-s-triazines, 2-halomethyl-4-vinyl-[l,3,4]oxadiazole, halogenoxazoles substituted with trichloromethyl groups, carbonylmethylene heterocycles containing trihalomethyl groups according to DE-A 33 33 450, acylphosphine oxide compounds, as described for example in DE-A 31 33 419, and other phosphorus-containing photoinitiators, &zgr;. B. the 6-acyl-6H-dibenzo[c,e][1,2]oxaphosphorine-6-oxides described in DE-A 37 28 168, in particular the 6-(2,4,6-trimethylbenzoyl)-6H-dibenzo[c,e][1,2]oxaphosphorine-6-oxide. The photo-0 initiators can also be used in combination with one another or with coinitiators or activators, e.g. with Michler's ketone and its derivatives or 2-alkyl-anthraquinones. The amount of photoinitiator is generally about 0.01 to

HOECHST AKTIENGESELLSCHAFT - PLANT 3CALLE-ALBERT

10% by weight, preferably about 0.5 to 5% by weight of the recording material.

It is often advantageous to add further auxiliary substances and additives to the recording material, e.g. those that inhibit thermal polymerization, such as hydroquinone and its derivatives, 2,6-di-tert-butyl-p-cresol, nitrophenols, nitrosamines such as N-nitrosodiphenylamine or salts of N-nitrosocyclohexylhydroxylamine, e.g. its alkali or aluminum salts. Other common additives are dyes, pigments, processing aids and plasticizers.

The mixtures according to the invention can be processed for the production of relief and flexographic printing plates by casting from solution or extruding and calendering to give layers with a thickness of 0.02 to 6 mm, preferably from 0.2 to 3 mm. The layer can be laminated to the surface of a suitable support 0 or a solution of the mixtures according to the invention can be applied directly to a layer support.

In addition to the production of relief printing plates, the mixtures can also be used according to the innovation for example for the production of planographic printing plates, gravure cylinders, screen printing stencils and photoresists.

Depending on the intended use, suitable supports include polyester films, steel or aluminum sheets, copper cylinders, screen printing stencil supports, foam layers, rubber-elastic supports or circuit boards. It can also be advantageous to apply a cover or protective layer to the light-sensitive recording layer.

HOECHST AKTIENGESELLSCHAFT - WE-^K miXM -ALBERT

e.g. a thin layer of polyvinyl alcohol or polyamide, or a removable cover film, e.g. made of polyethylene terephthalate. Furthermore, a pre-coating of the carrier can be advantageous. The additional layer between the carrier and the light-sensitive layer can, for example, act as an antihalation layer or as an adhesive layer.

The recording materials according to the innovation can be exposed imagewise with actinic light from light sources such as mercury vapor lamps or fluorescent tubes, the emitted wavelength preferably being between 300 and 420 nm. The unexposed and uncrosslinked layer portions can be removed by spraying, washing or brushing with water or basic, aqueous solutions. Examples of basic materials that can be considered are hydroxides, carbonates or hydrogen carbonates of alkali metals, ammonia and organic amines. Wetting and emulsifying agents as well as water-miscible organic solvents such as aliphatic alcohols, ethylene glycols and ethylene glycol monoethers can also be added. The proportion of basic components in the solution is generally 0.01 to 5% by weight, preferably 0.1 to 1% by weight. The proportion of organic solvent is less than 40% by weight, preferably less than 20% by weight.

Alternatively, organic solvents such as aromatic hydrocarbons, chloroalkanes and ketones can be used as developers. Examples of these are toluene, xylene, 1,1,1-trichloroethane, tetrachloroethylene, methyl isobutyl ketone and others, which

HOECHST AKTIENGESELLSCHAFT - KALLE-ALBERT PLANT

can also be used in combination with lower alcohols, e.g. n-butanol. The developed relief forms are preferably dried at temperatures up to 120 "C and, if necessary, photochemically or chemically treated.

The recording materials according to the innovation are particularly suitable for the production of printing forms, especially relief or letterpress printing forms, which are particularly suitable for flexographic printing.

The innovation is explained by the following examples. Unless otherwise stated, % figures are by weight.

Manufacturing example:

In a dry glass autoclave or glass apparatus, 1.33 ml of 1.6 M n-BuLi solution in hexane is added to a mixture of 40 ml of toluene and 80.6 mmol of styrene under an inert gas atmosphere. The warming reaction mixture is stirred in a water bath for 2 hours, diluted with 160 ml of toluene and, after adding 500 mmol of isoprene, stirred for a further 2.5 hours. The viscous reaction solution is mixed with 3.80 mmol of 1,1-diphenylethene and 200 ml of THF. It is then cooled with a NaCl/ice-water mixture. After adding 99.6 mmol t-butyl methacrylate, the mixture is stirred in a cold bath for 1 h and the polymerization is stopped with 1 ml methanol. The 0 reaction solution is then finely divided into 10 times the volume of methanol. The precipitated polymer is filtered off, washed and dried. To remove the t-butyl protective group, the isolated material is dissolved in toluene, with

HOECHST AKTIENGESELLSCHAFT - PLANT XALIiE- ALBERT

5 wt.% p-toluenesulfonic acid, based on t-butyl methacrylate, and heated to 80 °C for 6 h. After cooling, it is precipitated with MeOH, washed and dried in vacuo at room temperature.
5

Yield: 97% (83%); Mp (GPC): 49000 (before cleavage of the tert-butyl protective group); SZ: 68.0 mg KOH/g

Example 1:

37.0 g of an S-I-MAA block copolymer synthesized according to the preparation example with 19% styrene, 71% isoprene and 10% methacrylic acid,

37.0 g of a SIS block copolymer ('' Europren Sol T 190),

16.0 g liquid polyisoprene (^ ^R ^Kuraray LIR 403), 8.5 g trimethylolpropane triacrylate,
1.0 g benzil dimethyl ketal and
0.5 g 2,6-di-tert-butyl-4-methyl-phenol
20

are dissolved in 3 00 g of toluene and then poured into a drying frame. The light-sensitive layer obtained after evaporation of the solvent is pressed in a plate press between two 0.125 mm thick polyester films provided with an adhesive or anti-tack layer to a layer thickness of 3.0 mm. After 20 s of exposure to the back, the plate is exposed imagewise for 8 min in a UVA flat-panel exposure unit and then treated with a developer consisting of 15 0 parts of diethylene glycol monobutyl ether and 85 parts of a 1% aqueous sodium hydroxide solution at 60 ⁰ C for 20 min. The exposed plate has a Shore A hardness of 30 and gives a

HOECHST AKTIENGESELLSCHAFT - KALLE-AtBBRT PLANT

Ethyl acetate has a swelling value of 0.3%, 1.4% and 5.2% respectively.

Examples 2 to 9;

Analogous to Example 1, further photopolymer printing plates are produced with the compositions described in Table 1 and, after exposure, developed according to Example 1. The corresponding values for hardness and swelling are summarized in Table 2.

Table 1

20 25

Components ¹ ^ , 2) d) Photopolymer blends 2 3 4 5 6 7 8th 9 S-I-MAA (10%-80%-10%), Mp = 142 000 liquid epoxidized polybutadiene ^e ' 37% - - - - - - - S-I-MAA (20%-70%-10%) M = 59 000 - 37% - - - - - - S-I-MAA (10%-75%-15%), M = 52 000 - - 9.0% - - - - - S-I-MAA (10%-75%-15%), Mp = 56 000 - - 36% - - - - - S-I-MAA (10%-80%-10%) M = 94 000 - - - 48% - - - - S-I-MAA (20%-70%-10%), M = 126 000 - - - - 74% 37% 56% - I-MAA (90%-10%) M^ = 83 000 - - - - - - - 40% SIS block copolymer ^c 37% 37% 30% - - 37% 18% - Chlorosulfonated polyethylene °' - - - 32% - - - - SIS block copolymer ^c ' - - - - - - - 35% liquid polyisoprene 16% 16% - - 16% 16% 16% - - - - - - - - 12%

cn &igr;

Table 1. Continued

Components Photopolymer blends 2 3 4 5 6 7 8th 9 Trimethylolpropane triacrylate 8.5% 8.5% 3.5% 8.5% 8.5% 8.5% 8.5% - Tripropylene glycol diacrylate - - 5.0% - - - - - 2,3-Glyceryl dimethacrylate - - 10% - - - - - Polyethylene glycol-^OO-dimethacrylate - - - 5.0% - - - 4.0% Dimethylaminoethyl methacrylate - - - 5.0% - ■ - - - Pentaerythritol triacrylate - - - - - - - 8.0% Benzil dimethyl ketal 1.0% 1.0% 1.0% 1.0% 1.0% 1.0% 1.0% 1.0% 2,6-di-tert-butyl-4-methylphenol 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% Triethanolamine - - 5.0% - - - - -

^a ) (R)EUROPRENE Sol T 190 (EniChem Elastomer! SpA)

t>) (R) HYPALON 40 (E.I. du Pont de Nemours & Co.)

c) (R)cARIFLEX TR 1107 (Shell Elastomers)

d) (R)kuRARAY LIR (Kuraray Isoprene Chemicals Co., Ltd.)

e) (R)poLYVEST OE 29 (Hüls Aktiengesellschaft)

HOECHST AKTIENGESELLSCHAFT - WEAK X ALLE-ALBERT

Table 2 Swelling and hardness values of photopolymer mixtures

10 15 20 25

30

35

At
game
No. _H2O EtOH EtOH/EtOAc
(85/15) hardness
after
30s 2 0.25% 1.7% 5.9% 43 Shore A 3 0.20% 0.46% 5.6% 43 Shore A 4 0.65% 0.67% 4.7% 4 3 Shore A 5 0.88% 0.79% 3.8% 38 Shore A 6 3.9% 17% 30% 56 Shore A 7 1.1% 2.9% 7.9% 53 Shore A 8th 0.80% 2.5% 7 ? S; 31 Shore A 9 2.8% 3.9% 9 5 3; 25 Shore A

Calculation after swelling = (m _24n -niQ)/m ₀ * 10 0

Europren

Example 10:

A mixture consisting of

80.0 g of an S-I-S block copolymer

Sol T 190)

80.0 g of a (SI) _n X(MAA) _n block copolymer (S = 9.2%, I = 79%, MAA = 9.8%, X = divinylbenzene = 2.1%, M_ = 225000),
17.0 g trimethylolpropane triacrylate,
20.0 g nonaethylene glycol dimethacrylate,
2.0g benzil dimethyl ketal and
1.0 g 2,6-di-tert-butyl-hydroxytoluene

are kneaded on a two-roll mill at 150 'C until a homogeneous, clear mass is formed.

HOECHST AKTIENGESELLSCHAFT - PLANT KALLK-A LBERi ¹ '

This light-sensitive mass is then pressed in a plate press at 120 °C between two 0.125 mm thick polyester films, each with an adhesive or anti-tack layer, to a layer thickness of 3.0 mm. After 20 s of exposure to the back, the plate is exposed imagewise for 8 minutes, treated for 10 minutes with the developer described in Example 1 at 60 °C and then dried for 24 hours at room temperature. The exposed printing plate has a Shore A hardness of 53 and gives swelling values in water, in ethanol or in a mixture of 85 parts ethanol and 15 parts ethyl acetate of 0.39%, 4.72% and 14.2% respectively.

Table appendix:

1) I= isoprene, MAA = methacrylic acid, S = styrene

2) M^ = average molecular weight (peak maximum of the 0 GPC curve) determined by GPC measurement with THF as solvent and polyisoprene as standard (material before removal of the protective groups)

Claims (10)

a) an elastomeric binder or binder mixture, b) a radically polymerizable low molecular weight compound compatible with the binder with at least one terminal, ethylenically unsaturated group and a boiling point at normal pressure above 100 "C and (c) a compound or combination of compounds which, under the action of actinic light, induces the polymerisation of the Connection (b) is capable of initiating contains, characterized in that a block copolymer of the general structure AB, BAB, CAB, CACB, BCACB, A _n XB _n , (AB) _n X, C _n X(AB) _n , (CA) _n XB _n , (CAB) _n X, C _n X(ACB) _n , (CA) _n X(CB) _n , (CAC) _n XB _n , (CACB) _n X, B _n XA _n XB _n , X(BAB) _n X, (BC) _n XA _n X(CB) _n , B _n X(CAC) _n XB _n or X(BCACB) _n X is used as the elastomeric binder, where A hydrophobic soft blocks (T < -30 "C), B hydrophilic hard blocks containing acidic groups included, (T > +30 ^e C), C hydrophobic hard blocks (T _g > +50 ⁰ C), X a unit formed from a compound with two or more vinyl or HOECHST AKTIENGESELLSCHAFT - KAtLiS-ALBERT PLANT isopropenyl groups or for a homopolymer block formed from such compounds, which is usually branched or cross-linked, and η indicates the numerical ratio of A/B/C homopolymer blocks to the unit X or to the homopolymer block X. 2. Light-curable elastomeric mixture according to claim 1, characterized in that the elastomeric block copolymer serving as a binder consists of 20 to 99% by weight of the polymer blocks A, 1 to 30% by weight of the polymer blocks B and 0 to 79% by weight of the polymer blocks C. 3. Light-curable elastomeric mixture according to claim 1, characterized in that the elastomeric block copolymer serving as a binder consists of the soft polymer blocks A made of conjugated dienes, the hard polymer blocks B made of ethylenically ce,ß-unsaturated carboxylic acids, and the hard polymer blocks C made of vinyl aromatics. 4. Light-curable elastomeric mixture according to claim 3, characterized in that the conjugated diene is 1,3-butadiene, isoprene or 2,3-dimethyl-1,3-butadiene. 5. Light-curable elastomeric mixture according to claim 3, characterized in that the ethylenically α,β-unsaturated carboxylic acid is acrylic acid or methacrylic acid. iioechst Aktiengesellschaft - werk kalle-albert 6. Light-curable elastomeric mixture according to claim 3, characterized in that the vinyl aromatic is styrene or vinyl naphthalene. 7. Light-curable elastomeric mixture according to claim 1, characterized in that the block copolymer serving as a binder has a molecular weight between 15,000 and 10,200,000 g/mol. 8. Light-curable elastomeric mixture according to claim 1, characterized in that the radically polymerizable compound is an ester or amide of acrylic, methacrylic, fumaric or maleic acid with a mono- or polyhydric alcohol or amine. 9. Light-curable elastomeric mixture according to claim 1, characterized in that it contains 20 to 95% by weight of elastomeric block copolymer, 5 to 70% by weight of polymerizable compounds and 0.01 to 10% by weight of photopolymerization initiator. 10. Light-curable recording material with a layer support and a light-curable layer, characterized in that the light-curable layer consists of a mixture according to one of the 3 0 Claims 1 to 9 exist.