Polymerisable composition

1. A reaction product comprising at least

a) acrylic acid or methacrylic acid or a mixture of acrylic acid and methacrylic acid and

b) a (meth)acrylic ester of substituted or unsubstituted phenol, C 1 -C 8 -hydroxyalkylbenzene or C 1 -C 8 -hydroxyalkoxybenzene and methyl(meth)acrylate in the ratio (percent by weight) of from 7.1:92.9 to 50:50,

5-90% of the acrylic or methacrylic acid units having reacted with a glycidylvinyl compound and wherein the ratio (percent by weight) of component a) to component b) is from 80:20 to 20:80.

2. A reaction product according to claim 1 , wherein component a) is methacrylic acid.

3. A reaction product according to claim 1 , wherein the (meth)acrylic ester of component b) is benzyl methacrylate.

4. A reaction product according to claim 1 , wherein the glycidylvinyl compound is glycidyl methacrylate.

5. A reaction product according to claim 1 , wherein the molecular weight of the reaction product is 10000-120000 g/mol.

6. A reaction product according to claim 1 , wherein the molecular weight of the reaction product is 20000-90000 g/mol.

7. A reaction product according to claim 1 , which has an acid number of 0.4-5.0 mol/kg, referred to the reaction product.

8. A photopolymerizable composition, substantially comprising

i) a reaction product according to claim 1 ,

ii) a monomeric or oligomeric acrylate having at least two ethylenically unsaturated, terminal groups,

iii) a polymerization initiator or initiator system which produces free radicals, cations or anions and can be activated by actinic radiation and,

iv) if desired, an organic or inorganic filler.

9. A photopolymerizable composition, substantially comprising

i) 15-70% by weight of the reaction product according to claim 1 ,

ii) 0-30% by weight of monomeric or oligomeric acrylate having at least two ethylenically unsaturated, terminal groups,

iii) 0.1-15% by weight of a polymerization initiator or initiator system which produces free radicals, cations or anions and can be activated by actinic radiation,

iv) 0-60% by weight of an organic or inorganic filler,

v) 0.01-0.5% by weight of a thermal polymerization inhibitor and

vi) 20-80% by weight of a solvent or solvent system,

the percentages of the components being based on the total weight, with the proviso that the sum of the percentages by weight is 100.

10. A photopolymerizable composition, substantially comprising

i) a reaction product according to claim 1 ,

ii) if desired, a monomeric or oligomeric acrylate having at least two ethylenically unsaturated, terminal groups,

iii) a polymerization initiator or initiator system which produces free radicals, cations, or anions, and can be activated by actinic radiation,

iv) if desired, an organic or inorganic filler,

v) a thermal polymerization inhibitor and

vi) a solvent or solvent system.

11. A process for producing an etch resist image or solder resist image, comprising the process steps:

I. Application of a photopolymerizable composition according to claim 10 to a substrate by means of an inkjet method;

II. removal of the solvent from the applied composition with formation of a dried photopolymerizable composition on the substrate;

III. if desired, uniform exposure of the coated or structured substrate to actinic radiation; and

IV. if desired, thermal curing and, if desired, UV curing of the coating remaining on the substrate.

12. A process for producing an etch resist image or solder resist image, comprising the process steps of:

I. Application of a photopolymerizable composition according to claim 10 to a substrate;

II. removal of the solvent from the applied composition with formation of a film of the photopolymerizable composition on the substrate;

III. if desired, exposure of the coated substrate to actinic radiation;

IV. if desired, removal of the unexposed parts of the coating with the aid of an alkaline-aqueous or organic solvent with baring of the substrate; and

V. if desired, thermal curing and, if desired, UV curing of the coating remaining on the substrate.

13. A process according to claim 12 , wherein the exposure (III) is effected with the aid of a photomask or directly by means of a laser.

14. A photopolymerizable element comprising a substrate which carries a photopolymerizable layer, substantially comprising

A) 25-85% by weight of the reaction product according to claim 1 ,

B) 5-40% by weight of monomeric or oligomeric acrylate having at least two ethylenically unsaturated, terminal groups;

C) 1-25% by weight of an addition polymerization initiator or initiator system which produces free radicals, cations, or anions and can be activated by actinic radiation;

D) 0-60% by weight of an organic or inorganic filler and

E) 0.025-1.0% by weight of a thermal polymerization inhibitor;

the percentages of the components being based on the total weight, with the proviso that the sum of the percentages by weight is 100.

15. A photopolymerizable element according to claim 14 , wherein the thickness of the photopolymerizable layer is 3-50 μm.