Anti-fouling cationically crosslinkable varnish compositions and support substrates coated therewith

A cationically polymerizable/crosslinkable varnish composition useful for providing anti-fouling coatings and comprising, per 100 parts by weight:

• 1. at least 80 parts by weight of at least one basic compound which comprises, per molecule, at least two polymerizable/crosslinkable functional groups, at least one of these groups being selected from the groups consisting of alkenyl ether, epoxy and oxetane;
• 2. from 0.1 to 10 parts by weight of at least one cationic initiator selected from among those in which the cationic moiety is an onium salt of formula (I):
• [(R1)n-A-(R2)m]+ (I)
• in which:
• A is an element of groups 15 to 17 of the Periodic Table;
• R1 is a C6-C20 carbocyclic or heterocyclic aryl radical, said heterocyclic radical optionally containing, as heteroelements, nitrogen or sulfur;
• R2 is R1 or a C1-C30 linear or branched alkyl or alkenyl radical, said radicals R1 and R2 optionally being substituted with a C1-C25 alkoxy, C1-C25 alkyl, nitro, chloro, bromo, cyano, carboxyl, ester or mercapto group;
• n is an integer ranging from 1 to v+1, v being the valency of the element A;
• m is an integer ranging from 0 to v−1 with n+m=v+1;
• and in which the anionic moiety of the initiator is a borate of formula (II):
• [BXaRb]− (II)
• in which:
• a and b are integers ranging, for a, from 0 to 3 and, for b, from 1 to 4, with a+b=4;
• the symbols X represent:
• a halogen atom with a=0 to 3,
• an OH function with a=0 to 2;
• the symbols R, which may be identical or different, are each:
• a phenyl radical substituted with at least one electron-withdrawing group, and/or with at least two halogen atoms, this being the case when the cationic moiety is an onium of an element of groups 15 to 17;
• a phenyl radical substituted with at least one element or one group that is electron-withdrawing;
• an aryl radical containing at least two aromatic rings, optionally substituted with at least one element or one group that is electron-withdrawing;
• 3. from 0 to 10 parts by weight of at least one polyorganosiloxane (POS) other than the basic compound 1 and which comprises, per molecule, at least one alkenylated group and/or at least one epoxy group;
• 4. from 0 to 10 parts by weight of at least one silylated compound which comprises, per molecule, at least one epoxy group;
• 5. from 0 to 10 parts by weight of at least one silylated compound which comprises, per molecule, at least one alkenylated group and at least one epoxy, alkenyl ether or oxetane group, with the provisos:
• a) the additive 3 and the additive 4 are necessarily present in the absence of additive 5;
• and
• b) the alkenylated-epoxidized additive 5 is necessarily present in the absence of additives 3 and 4;
• 6. from 0 to 10 parts by weight of at least one ultrafine filler;
• 7. from 0 to 10 parts by weight of at least one thickener;
• and
• 8. from 0 to 10 parts by weight of at least one other functional additive.