Initiator system comprising an onium borate and a cyclic group containing photoinitiator

Initiator system for polymerization and/or crosslinking, comprising:

• (1) at least one onium borate in which:
• (i) the cationic species is an onium salt of formula (I)
• [(R1)n—I—(R2)m]+ (I)
• in which formula:
• the radicals R1, which may be identical or different, represent a carbocyclic or heterocyclic C6-C20 aryl radical,
• the radicals R2, which may be identical or different, represent R1, a linear or branched C1-C30 alkyl radical or a linear or branched C1-C30 alkenyl radical,
• said radicals R1 and R2 optionally being substituted with:
• a linear or branched C1-C25 alkyl group,
• an alkoxy group OR13,
• a ketone group —(C═O)—R13,
• an ester or carboxylic group —(C═O)—O—R13,
• a mercapto group SR13,
• a mercapto group SOR13,
• R13 being a radical selected from the group consisting of a hydrogen atom, a linear or branched C1-C25, alkyl radical, a C6-C30 aryl radical and an alkylaryl radical in which the alkyl portion is linear or branched and C1-C23 and the aryl portion is C6-C30,
• a nitro group,
• a chlorine atom,
• a bromine atom, and/or
• a cyano group,
• n is an integer ranging from 1 to v+1, v being the valency of iodine,
• m is an integer with n+m=v+1;
• (ii) and the anionic borate species has the formula (II):
• [BXaR3b]− (II)
• in which:
• a and b are integers such that 0≦a≦4, 0≦b≦4, and a+b=4,
• the symbols X, which may be identical or different, represent:
• a halogen atom chosen from chlorine and/or fluorine with 0≦a≦3,
• an OH function with 0≦a≦2, and
• the radicals R3, which may be identical or different, represent:
• a phenyl radical substituted with at least one electron-withdrawing group or substituted with at least two halogen atoms,
• an aryl radical containing at least two aromatic nuclei, optionally substituted with at least one halogen atom, or with an electron-withdrawing group;
• (2) and at least one cyclic compound corresponding to one of the formulae (III) to (VI) below:
• in which:
• when n=1, Ar1 represents an aryl radical containing from 6 to 18 carbon atoms, a tetrahydronaphthyl, thienyl, pyridyl or furyl radical or a phenyl radical bearing one or more substituents selected from the group consisting of F, Cl, Br, CN, OH, linear or branched C1-C12 alkyls, —CF3, —OR6, —Ophenyl, —SR6, —Sphenyl, —SO2phenyl, —COOR6, —O—(CH2—CH═CH2), —O(CH2H4—O)m—H, and —O(C3H6O)m—H, m being 1 and 100,
• when n=2, Ar1 represents a C6-C12 arylene radical or a phenylene-T-phenylene radical, in which T represents —O—, —S—, —SO2— or —CH2—,
• X represents a group —OR7 or —OSiR9(R9)2 or forms, with R4, a group —O—CH(R10)—,
• R4 represents a linear or branched C1-C8 alkyl radical which is unsubstituted or bears a group —OH, —OR6, C2-C8 acyloxy, —COOR6, —CF3 or —CN, a C3 or C4 alkenyl radical, a C6 to C18 aryl radical or a C7 to C9 phenylalkyl radical,
• R5 has one of the meanings given for R4 or represents a radical —CH2CH2R11, or alternatively forms, with R4, a C2-C8 alkylene radical or a C3-C9 oxa-alkylene or aza-alkylene radical,
• R6 represents a lower alkyl radical containing from 1 to 12 carbon atoms,
• R7 represents a hydrogen atom, a C1-C12 alkyl radical, a C2-C6 alkyl radical bearing a group —OH, —OR6 or —CN, a C3-C6 alkenyl radical, a cyclohexyl or benzyl radical, a phenyl radical optionally substituted with a chlorine atom or a linear or branched C1-C12 alkyl radical or a 2-tetrahydropyranyl radical,
• R8 and R9 are identical or different and each represent a C1-C4 alkyl radical or a phenyl radical,
• R10 represents a hydrogen atom, a C1-C8 alkyl radical or a phenyl radical,
• R11 represents a radical —CONH2, —CONHR6, —CON(R6)2, —P(O)(OR6)2 or 2-pyridyl;
• in which:
• Ar2 has the same meaning as Ar1 in formula (III) in the case in which n=1,
• R15 is selected from the group consisting of a radical Ar2, a radical —(C═O)—Ar2, a linear or branched C1-C12 alkyl radical, a C6-C12 cycloalkyl radical and a cycloalkyl radical forming a C6-C12 ring with the carbon of the ketone or a carbon of the radical Ar2, it being possible for these radicals to be substituted with one or more substituents selected from the group consisting of —F, —Cl, —Br, —CN, —OH, —CF3, —OR6, —SR6, —COOR6, linear or branched C1-C12 alkyl radicals optionally bearing a group —OH, —OR6 and/or —CN;
• and linear or branched C1-C8 alkenyl radicals;
• in which
• Ar3 has the same meaning as Ar1 in formula (III) in the case in which n=1,
• R16, which may be identical or different, is selected from the group consisting of a radical Ar3, a radical —(C═O)—Ar3, a linear or branched C1-C12 alkyl radical, and a C6-C12 cycloalkyl radical, it being possible for these radicals to be substituted with one or more substituents selected from the group consisting of —F, —Cl, —Br, —CN, —OH, —CF3, —OR6, —SR6, —COOR6, linear or branched C1-C12 alkyl radicals optionally bearing a group —OH, —OR6 and/or —CN;
• and linear or branched C1-C8 alkenyl radicals;
• in which:
• R5, which may be identical or different, has the same meaning as in formula (III),
• Y, which may be identical or different, represent X and/or R4,
• Z represents:
• a direct bond,
• a C1-C6 divalent alkylene radical, or a phenylene, diphenylene or phenylene-T-phenylene radical, or alternatively forms, with the two substituents R5 and the two carbon atoms bearing these substituents, a cyclopentane or cyclohexane nucleus,
• a divalent group —O—R12—O—, —O—SiR8R9—O—SiR8R9—O— or —O—SiR8R9—O—,
• R12 represents a C2-C8 alkylene, C4-C6 alkenylene or a xylylene radical, and
• AR4 has the same meaning as Ar1 in formula (III) in the case in which n=1,
• wherein the weight ratio of onium borate to cyclic compound is between 0.1 and 10.