Polymerisable compositions, derived coatings and other polymerised products

Claim 2

A photopolymerisable composition capable of polymerisation by an acid-catalysed mechanism under the influence of ultraviolet and/or visible light which comprises the components: (a) at least one material capable of polymerisation by an acid catalysed mechanism to a polymeric material of higher molecular weight state; (b) a photosensitive aromatic sulphonium salt and (c) a material which under the conditions of photopolymerisation will yield a significant proportion of free radicals either (i) by intramolecular cleavage, or (ii) by intermolecular abstraction in conjunction with a component of the composition other than the photosensitive aromatic sulphonium salt.

Claim 3

A photopolymerisable composition according to claim 1 wherein the photosensitive sulphonium salt is represented by the formula : wherein n is 1 or 2; R 1 , R 2 and R 3 , which may be the same or different, each is a hydrocarbon or substit- u ed hydrocarbon group or heterocyclic group or two of the groups R l , R 2 and R 3 together with the S atom are a heterocyclic structure, the other group R being a hydrocarbon group or substituted hydrocarbon group, at least one group R attached to the S atom being an aromatic group; X n- is an anion derived from an acid which is capable of polymerising the material (a) of the composition by an acid-catalysed mechanism to a higher molecular weight state. A photopolymerisable composition according to claim 2 wherein X n- is selected from BF 4 - , SbCl 6 - , SbF 6 - , SnCl 6 - , PF 6 - , AsF 6 - , FeCl 4 - , BiCl 5 - , or R 5 SO 3 where R 5 is an aromatic hydrocarbon radical having 6-13 carbon atoms, an alkyl radical having 1-8 carbon atoms, and halogenated derivatives thereof, or R 5 is fluorine. A photopolymerisable composition according to any one of claims 1 to 3 wherein a component (c) (i) is selected from benzoin and benzoin alkyl ethers; alkoxy aryl acetophenones; and halogenated acetophenones, or a component (c)(ii) is selected from aromatic diketones and derivatives thereof; benzophenone and derivatives thereof; materials of structure where X=O, S, CH 2 or a direct carbon-to-carbon bond and derivatives thereof where R = halogen, alkyl or substituted alkyl. A photopolymerisable composition according to any one of claims 1 to 4 wherein there is present 0.01 to 10% by weight based on the composition of the component (c). A photopolymerisable composition according to any one of claims 1 to 5 wherein the material capable of polymerisation to a higher molecular weight state is selected from epoxides, episulphides, and other cyclic ethers and thioethers; epoxy resins; episulphide resins; vinyl ethers; phenolic resins; and aminoplasts. A photopolymerisable composition according to any one of claims 1 to 6 which is substantially free of material polymerisable by free radicals. A photopolymerisable composition according to any one of claims 1 to 7 comprising a further component (d) which plays no part in the polymerisation process but which, when the composition is irradiated with ultraviolet and/or visible light, absorbs at least some of that radiation to which, in the absence of said component (d), the sulphonium salt would be sensitive. A coating composition which comprises a photopolymerisable composition according to claim 8 and in which the component (d) is a pigment. A polymerised composition obtained by irradiating with ultraviolet and/or visible light a composition according to any one of claims 1 to 9.