COMPOSITION USEFUL AS A PRESSURE SENSITIVE ADHESIVE, ITS USE AND ADHESIVE ARTICLES COMPRISING IT

1 . A composition comprising:

a. at least one copolymerizable (meth)acrylic monomer;

b. optionally, at least one copolymerizable non-acrylic monomer;

c. at least one copolymerizable photoinitiator;

d. optionally, a solvent; and

e. optionally, one or more non-copolymerizable photoinitiators;

wherein the at least one copolymerizable photoinitiator (c) is a compound of formula (I)

wherein

X is selected from S and NR′;

R′ is selected from hydrogen and linear or branched C 1-10 alkyl groups;

R 1 , R 2 and R 3 , each independently, are selected from hydrogen, C 1-6 alkyl groups, halogens, amino groups, nitro groups, nitrile groups, hydroxyl groups, C 1-6 alkoxide groups;

R 4 is selected from hydrogen, —COOH, —CH 2 CO 2 H and a methyl group,

wherein said at least one copolymerizable (meth)acrylic monomers (a) is selected from:

i. hydroxyalkyl acrylic or methacrylic acid esters, wherein alkyl groups have 2-18 carbon atoms, and are selected from the group consisting of 2-hydroxyethyl ethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and mixture thereof;

ii. alkyl acrylic or methacrylic acid esters, wherein alkyl groups have 2-18 carbon atoms, and are selected from the group consisting of n-butyl acrylate, n-butyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl acrylate and mixture thereof;

iii. alkoxyalkyl of acrylic or methacrylic acid esters, wherein alkyl groups ae have 2-18 carbon atoms, and are selected from the group consisting of methoxyethyl acrylate, methoxyethyl methacrylate, butoxyethyl acrylate, butoxyethyl methacrylate and mixture thereof;

iv. monomers of formula (II)

R 5 —(OCH 2 CHR 7 ) n L-O(CO)—CR 6 ═CH 2   (II)

wherein R 5 is hydrogen or a C 1 -C 6 alkyl group, n is an integer from 1 to 100, L is a single bond or a divalent linking group, R 6 is hydrogen or a CH 3 group, and R 7 is a hydrogen or a methyl group;

and mixtures thereof.

2 . The composition according to claim 1 , wherein said at least one copolymerizable non-acrylic monomers (b) is selected from α,β-unsaturated monocarboxylic, dicarboxylic acids, anhydride, alkyl or alkenyl esters thereof, wherein alkyl groups have 1 to 3 carbon atoms and alkenyl groups have 2-5 carbon atoms; acrylic acid, itaconic acid, maleic acid, maleic anhydride, ethyl methacrylate ester ethyl methacrylate ester, fumaric acid, vinyl monomers, vinyl acetate, acrylonitrile, vinyl propionate, vinyl pyrrolidone, styrene, alpha methyl styrene, ACMO (acryloyl morpholine) and styrene 4-sulfonic acid.

3 . The composition according to claim 1 , wherein the solvent (d) is selected from alcohols, ketones, ethers, aliphatic hydrocarbons, aromatic hydrocarbons, esters and mixtures thereof and said thermal initiator (e), if present, is selected from azo compounds, 2,2′azobis(isobutyronitrile), peroxides, benzoyl peroxide, t butyl peroxy-2-ethylhexanoate, dilauryl peroxide, percarbonates and di(4-tert-butyl cyclohexyl peroxydicarbonate.

4 . The composition according to claim 1 , wherein said at least one monomer (a) is selected from methoxypropyleneglycol acrylate, methoxypropyleneglycol methacrylate, methoxypolyethyleneglycol acrylate, methoxypolyethyleneglycol methacrylate, and mixture thereof.

5 . The composition according to claim 1 , wherein said at least one monomer (a) is a mixture of monomers (i) to (iv), said mixture being selected from a mixture of methoxy polyethyleneglycol methacrylate, 2-ethylhexyl acrylate, methyl acrylate and acrylic acid and a mixture of methoxy polyethyleneglycol methacrylate, methacrylic acid, butyl methacrylate and/or 2-ethylhexylmethacrylate.

6 . The composition according to claim 1 , wherein X is S, R 1 , R 2 and R 3 are hydrogen and R 4 is methyl.

7 . A random copolymer obtainable by polymerizing a composition according to claim 1 .

8 . The random copolymer of claim 7 , characterized in that it comprises 0.25 to 10% by weight or less of a copolymerizable photoinitiator (c) according to formula (I) said percentages being based on the total weight of components (a), (b), (c) and (e).

9 . The random copolymer of claim 7 , wherein said polymerizing is carried out by UV irradiation.

10 . A method of preparing a pressure sensitive adhesive composition with a copolymerizable photoinitiator (c) of formula (I)

wherein

X is selected from S and NR′;

R′ is selected from hydrogen and linear or branched C 1-10 alkyl groups;

R 1 , R 2 and R 3 , each independently, are selected from hydrogen, C 1-6 alkyl groups, halogens, amino groups, nitro groups, nitrile groups, hydroxyl groups, C 1-6 alkoxide groups;

R 4 is selected from hydrogen, —COOH, —CH 2 CO 2 H and a methyl group.

11 . The method according to claim 10 , wherein in the compound of formula (I) X is S; R 1 , R 2 and R 3 are hydrogen and R 4 is methyl.

12 . The method according to claim 10 , wherein said composition is a random copolymer obtainable by polymerizing a composition comprising:

f. at least one copolymerizable (meth)acrylic monomer;

g. optionally, at least one copolymerizable non-acrylic monomer;

h. at least one copolymerizable photoinitiator;

i. optionally, a solvent; and

j. optionally, one or more non-copolymerizable photoinitiators;

wherein the at least one copolymerizable photoinitiator (c) is a compound of formula (I)

wherein

X is selected from S and NR′;

R′ is selected from hydrogen and linear or branched C 1-10 alkyl groups;

R 1 , R 2 and R 3 , each independently, are selected from hydrogen, C 1-6 alkyl groups, halogens, amino groups, nitro groups, nitrile groups, hydroxyl groups, C 1-6 alkoxide groups;

R 4 is selected from hydrogen, —COOH, —CH 2 CO 2 H and a methyl group,

wherein said at least one copolymerizable (meth)acrylic monomers (a) is selected from:

v. hydroxyalkyl acrylic or methacrylic acid esters, wherein alkyl groups have 2-18 carbon atoms, and are selected from the group consisting of 2-hydroxyethyl ethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and mixture thereof;

vi. alkyl acrylic or methacrylic acid esters, wherein alkyl groups have 2-18 carbon atoms, and are selected from the group consisting of n-butyl acrylate, n-butyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl acrylate and mixture thereof;

vii. alkoxyalkyl of acrylic or methacrylic acid esters, wherein alkyl groups have 2-18 carbon atoms, and are selected from the group consisting of methoxyethyl acrylate, methoxyethyl methacrylate, butoxyethyl acrylate, butoxyethyl methacrylate and mixture thereof;

viii. monomers of formula (II)

R 5 —(OCH 2 CHR 7 ) n L-O(CO)—CR 6 ═CH 2   (II)

wherein R 5 is hydrogen or a C 1 -C 6 alkyl group, n is an integer from 1 to 100, L is a single bond or a divalent linking group, R 6 is hydrogen or a CH 3 group, and R 7 is a hydrogen or a methyl group; and mixtures thereof, or a crosslinked product obtained by UV irradiating said random copolymer of.

13 . The method claim 11 , wherein said adhesive is a pressure sensitive adhesive (PSA), for wound dressing devices.

14 . (canceled)