RADIATION CURABLE COMPOSITIONS
A composition comprising at least one curable compound (I) advantageously having a refractive index Formula (I) of at least 1.60 and obtained from the reaction of A at least one aromatic polyisocyanate, B at least one monofunctional alcohol or amine, C at least one further monofunctional alcohol or amine different from B, D at least one diol or diamine, and E optionally a hydroxyl group containing (meth)acrylate, the compound (I) comprising at least one curable functional group selected from the group consisting of carbon-carbon double bonds and epoxy groups. n D 20 (I)
1 . A composition comprising at least one curable compound (I) obtained from the reaction of
A at least one aromatic polyisocyanate,
B at least one monofunctional alcohol or amine,
C at least one further monofunctional alcohol or amine different from B,
D at least one diol or diamine, preferably having a refractive index n D 20 of at least 1.50, and
E optionally a hydroxyl group containing (meth)acrylate,
the compound (I) comprising at least one curable functional group selected from the group consisting of carbon-carbon double bonds and epoxy groups.
2 . The composition of claim 1 wherein the compound (I) is a urethane (meth)acrylate.
3 . The composition of claim 2 wherein the urethane (meth)acrylate comprises at least 2 (meth)acrylate functions.
4 . The composition of claim 1 wherein at least one of the compounds B, C and/or D comprises at least one (meth)acryloyl group and/or wherein the (meth)acryloyl group is provided by compound E.
5 . The composition of claim 1 wherein compounds B and C are aromatic monofunctional alcohols and wherein compound D is an aromatic diol.
6 . The composition of claim 1 wherein compound D comprises at least one (meth)acryloyl group.
7 . The composition of claim 1 wherein the compound (I) is an asymmetric molecule.
8 . The composition of claim 1 wherein the content of halogen and/or sulphur in said compound (I) is less than 2.0% by weight.
9 . The composition of claim 1 wherein the ratio of Eq. B /Eq. A and of respectively Eq. C /Eq. A is between 0.05 and 0.60, wherein Eq. A represents the equivalent number of compound A and Eq. B or Eq. C represents the equivalent number of compounds B or C respectively.
10 . The composition of claim 1 wherein the ratio of Eq. D /Eq. A is between 0.1 and 0.9, wherein Eq. A represents the equivalent number of compound A and wherein Eq. D represents the equivalent number of compound D.
11 . The composition of claim 9 wherein the sum of the ratios of Eq. B /Eq. A and Eq. C /Eq. A is between 0.10 and 0.80.
12 . The composition of claim 1 wherein compound A has a refractive index n D 20 of at least 1.53, compound D has a refractive index n D 20 of at least 1.50, and at least one of the compounds B and C has a refractive index n D 20 of at least 1.55.
13 . The composition of claim 1 wherein the at least one curable compound (I) has a refractive index n D 20 of at least 1.60.
14 . A process for the preparation of a composition of claim 1 wherein
in a first step compounds B and C are reacted with compound A, and wherein in a second step the reaction product thus obtained is further reacted with compound D, or wherein
in a first step compound D is reacted with compound A, and wherein in a second step the reaction product thus obtained is further reacted with compounds B and C.
15 . A method for making films and coatings wherein a composition of claim 1 is used.
16 . Coatings and films obtained from a composition of claim 1 .