POLYMERIZABLE COMPOSITION AND ITS USES

1 . A polymerizable composition, comprising:

(a) at least one monomer of formula (I):

wherein X 1 and X 2 are each independently H or C 1 -C 4 alkyl; Y 1 , Y 2 , Y 3 and Y 4 are each independently H, C 1 -C 4 alkyl or OH; and a and b are each independently an integer from 0 to 5; and

(b) a photo-initiator.

2 . The composition as claimed in claim 1 , wherein X 1 , X 2 Y 1 , Y 2 , Y 3 and Y 4 are each independently H or methyl; and a and b are each independently an integer from 1 to 3.

3 . The composition as claimed in claim 1 , wherein the monomer of formula (I) has formula (I 1 ):

4 . The composition as claimed in claim 1 , wherein the monomer of formula (I) is present in an amount ranging from 1 wt % to 50 wt %, based on the total weight of the polymerizable composition.

5 . The composition as claimed in claim 1 , wherein the monomer of formula (I) is present in an amount ranging from 3 wt % to 25 wt %, based on the total weight of the polymerizable composition.

6 . The composition as claimed in claim 1 , wherein the monomer of formula (I) is present in an amount ranging from 4 wt % to 20 wt %, based on the total weight of the polymerizable composition.

7 . The composition as claimed in claim 1 , wherein the photo initiator is selected from the group consisting of benzophenone, benzoin, benzil, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy cyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide and a combination thereof.

8 . The composition as claimed in claim 1 , wherein the photo initiator is present in an amount ranging from 0.1 wt % to 10 wt %, based on the total weight of the polymerizable composition.

9 . The composition as claimed in claim 1 , further comprising (d) an acrylate monomer of formula (II):

wherein R 3 is a straight or branched chain hydrocarbon having 2 to 6 carbon atoms, which is optionally interrupted by one or more heteroatoms selected from oxygen and sulfur; and n is an integer from 0 to 3.

10 . The composition as claimed in claim 9 , wherein the monomer of formula (II) is present in an amount ranging from 1 wt % to 80 wt %, based on the total weight of the polymerizable composition.

11 . The composition as claimed in claim 9 , wherein the monomer of formula (II) is present in an amount ranging from 8 wt % to 70 wt %, based on the total weight of the polymerizable composition.

12 . The composition as claimed in claim 9 , wherein the monomer of formula (II) is present in an amount ranging from 12 wt % to 60 wt %, based on the total weight of the polymerizable composition.

13 . The composition as claimed in claim 1 , further comprising (d-1) an acrylate monomer selected from the group consisting of acrylates, methacrylates, 2-phenoxyl ethyl acrylate, trimethylolpropane triacrylate, cumyl phenoxyl ethyl acrylate, propoxylated neopentyl glycol diacrylate, ethoxylated trimethylolpropane triacrylate, propoxylaed trimethyloipropane triacrylate, dipentaerythritol hexaacrylate, and a mixture thereof.

14 . The composition as claimed in claim 13 , wherein the acrylate monomer is present in an amount ranging from 1 wt % to 80 wt %, based on the total weight of the polymerizable composition.

15 . The composition as claimed in claim 1 , further comprising (c) a crosslinking agent.

16 . The composition as claimed in claim 15 , wherein the crosslinking agent is a (meth)acrylate, a urethane acrylate, a polyester acrylate, an epoxy acrylate, or a combination thereof.

17 . The composition as claimed in claim 15 , wherein the crosslinking agent is present in an amount ranging from 1 wt % to 60 wt %, based on the total weight of the polymerizable composition.

18 . The composition as claimed in claim 15 , wherein the crosslinking agent is present in an amount ranging from 10 wt % to 50 wt %, based on the total weight of the polymerizable composition.

19 . The composition as claimed in claim 15 , wherein the crosslinking agent is present in an amount ranging from 25 to 40 wt %, based on the total weight of the polymerizable composition.

20 . The composition as claimed in claim 1 , further comprising an additive selected from the group consisting of a slip agent, inorganic fillers, a leveling agent, a defoamer, an anti-static agent and a combination thereof.

21 . The composition as claimed in claim 18 , wherein the inorganic fillers are selected from the group consisting of titanium dioxide, silicon dioxide, strontium titanate, zinc oxide, alumina, barium sulfate, calcium sulphate, calcium carbonate, zirconia and a combination thereof.

22 . The composition as claimed in claim 18 , wherein the inorganic fillers have a particle size of 10 nm to 350 nm.

23 . A polymerizable composition, comprising:

(a) at least one monomer of formula (I):

wherein X 1 and X 2 are each independently H or methyl; Y 1 , Y 2 , Y 3 and Y 4 are each independently H or methyl; and a and b are each independently an integer from 1 to 3;

(b) a photo-initiator selected from the group consisting of benzophenone, benzoin, benzil, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy cyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide and a combination thereof; and

(c) a crosslinking agent selected from the group consisting of acrylates, methacrylates, urethane acrylates, polyester acrylates, epoxy acrylates and a combination thereof,

wherein the amount of the monomer of formula (I), based on the total weight of the polymerizable composition, is at least 1 wt %.

24 . The composition as claimed in claim 23 , wherein the monomer of formula (I) has formula (I 1 ):

25 . The composition as claimed in claim 23 , further comprising (d) a monomer of formula (II 1 ):

26 . An optical film, comprising a coating layer formed from the polymerizable composition as claimed in claim 1 .

27 . The optical film as claimed in claim 26 , wherein the coating layer has light-gathering structures.

28 . The optical film as claimed in claim 26 , wherein the coating layer has a refractive index of more than 1.53.

29 . The optical film as claimed in claim 26 , wherein the coating layer has a refractive index ranging from 1.53 to 1.62.

30 . The optical film as claimed in claim 26 , wherein the coating layer has a thickness from 1 μm to 100 μm.

31 . An optical film, comprising a coating layer formed from the polymerizable composition as claimed claim 23 .