Radiation-curable prepolymers

A radiation-curable prepolymer obtained by reacting an ethylenically unsaturated amine or an ethylenically unsaturated monohydroxy compound or a mixture thereof with an isocyanate-capped polyurethane,

• wherein said isocyanate-capped polyurethane is copolymerization product of:
• (a) at least one poly(ethylene glycol) and at least one hydroxy-terminated poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) or poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) tri-block copolymer;
• (b) one or more linear or branched aliphatic polyhydroxy compounds of formula
• R4—(OH)x (2)
• wherein R4 is a linear or branched C3–C18 aliphatic multi-valent radical and x is a number from 3 to 8;
• and
• (c) one or more diisocyanates of formula
• OCN—R5—NCO (3a),
• wherein R5 is a linear or branched C3–C18-alkylene, an unsubstituted or C1–C4-alkyl-substituted or C1–C4-alkoxy-substituted C6–C10-arylene, a C7–C18-aralkylene, a C6–C10-arylene-C1-C2-alkylene-C6–C10-arylene, a C3–C8-cyclo-alkylene, a C3–C8cycloalkylene-C1–C6-alkylene, a C3–C8-cycloalkylene-C1–C2-alkylene-C3–C8-cycloalkylene, or a C1–C6-alkylene-C3–C8-cycloalkylene-C1–C6-alkylene,
• wherein said ethylenically unsaturated amine is selected from the group consisting of mono-C1–C4 alkylamino-C1–C4 alkyl-acrylates, mono-C1–C4 alkylamino-C1–C4 alkyl-methacrylates, di-C1–C4alkylamino-C1–C4alkyl-acrylates and di-C1–C4alkylamino-C1–C4 alkyl-methacrylates,
• and wherein said ethylenically unsaturated hydroxy compound is selected from the group consisting of hydroxy-substituted C1–C6 alkylacrylates and hydroxy-substituted C1–C6 alkylmethacrylates,
• wherein said ethylenically unsaturated monohydroxy compound is a hydroxy-substituted lower alkylacrylate, a hydroxy-substituted lower alkylmethacrylate, a hydroxy-substituted lower alkyl-acrylamides, a hydroxy-substituted lower alkyl-methacrylamide, or a hydroxy-substituted lower alkylvinylether, wherein said ethylenically unsaturated amine has formula (4), (4′) or (4″)
• In which, I, j and k, independent of one another, are o or 1,
• R6 is hydrogen, a linear or branched C1–C24 alkyl, a C2–C24 alkoxyalkyl, a C2–C24 alkylcarbonyl, a C2–C24 alkoxycarbonyl, an unsubstituted or C1–C4 alkyl- or C1–C4 alkoxy-substituted C6–C10 aryl, a C7–C18 aralkyl, a C13–C22 arylalkylaryl, a C3–C8 cycloalkyl, a C4–C14cycloalkylalkyl, a C7–C18 cycloalkylalkylcycloalkyl, a C5–C20 alkylcycloalkylalkyl, or an aliphatic-heterocyclic radical,
• Z is a C1–C12 alkylene radical, phenylene radical or C7–C12 aralkylene radical,
• R7 and R7′, independently of each other, are hydrogen, C1–C4 alkyl or halogen;
• and
• Q is a radical of formula (5)
• wherein q is the number 0 or 1,
• each of R8 and R9 independently of the other is hydrogen, C1–C4 alkyl, phenyl, carboxy or halogen,
• R10 is hydrogen, C1–C4 alkyl or halogen, and
• Z′ is a linear or branched C1–C12 alkylene, an unsubstituted phenylene, an C1–C4 alkyl- or C1–C4 alkoxy-substituted phenylene, or a C7–C12 aralkylene.

A radiation-curable prepolymer obtained by reacting an ethylenically unsaturated amine or an ethylenically unsaturated monohydroxy compound or a mixture thereof with an isocyanate-capped polyurethane, wherein said isocyanate-capped polyurethane is copolymerization product of:

• (b) at least one poly(ethylene glycol) and at least one block copolymer of formula
• HO—(R1—O)n—(R2—O)m—H (1′)
• wherein R1 and R2, independently of one other, are each linear or branched C2–C4-alkylene, and n and m, independently of one another, are each a number from 1 to 100, wherein the sum of (n+m) is 5 to 100,
• (c) at least one branching agent selected from the group consisting of
• (ii) a linear or branched aliphatic polyhydroxy compound of formula
• R4—(OH)x (2),
• wherein R4 is a linear or branched C2–C18 aliphatic multi-valent radical and x is a number ≧3,
• (ii) a polyether polyol, which is the polymerization product of a compound of formula (2) and a glycol,
• (iii) a polyester polyol, which is the polymerization product of a compound of formula (2), a dicarboxylic acid or a derivative thereof and a diol, and
• (iv) a cycloaliphatic polyol selected from the group consisting of a C5–C5-cycloalkane which is substituted by ≧3 hydroxy groups and which is unsubstituted by alkyl radical, a C5–C8-cycloalkane which is substituted by ≧3 hydroxy groups and which is substituted by one ore more C1–C4 alkyl radicals, and an unsubstituted mono- and disaccharide, and
• (v) an aralkyl polyol having at least three hydroxy C1–C4 alkyl radicals, and
• (c) at least one di- or polyisocyanate of formula
• R5—(NCO)y (3)
• wherein R5 is the radical of an aliphatic, cycloaliphatic, aliphatic-cycloaliphatic, aromatic or araliphatic di- or polyisocyanate and y is a number from 2 to 6,
• wherein said ethylenically unsaturated monohydroxy compound is a hydroxy-substituted lower alkylacrylate, a hydroxy-substituted lower alkylmethacrylate, a hydroxy-substituted lower alkyl-acrylamides, a hydroxy-substituted lower alkyl-methacrylamide, or a hydroxy-substituted lower alkylvinylether, wherein said ethylenically unsaturated amine has formula (4), (4′) or (4″)
• In which, I, j and k, independent of one another, are o or 1;
• R6 is hydrogen, a linear or branched C1–C24 alkyl, a C2–C24 alkoxyalkyl, a C2–C24 alkylcarbonyl, a C2–C24 alkoxycarbonyl, an unsubstituted or C1–C4 alkyl- or C1–C4 alkoxy-substituted C6–C10 aryl, a C7–C18 aralkyl, a C13–C22 arylalkylaryl, a C3–C8 cycloalkyl, a C4–C14cycloalkylalkyl, a C7–C18 cycloalkylalkylcycloalkyl, a C5–C20 alkylcycloalkylalkyl, or an aliphatic-heterocyclic radical;
• Z is a C1–C12 alkylene radical, phenylene radical or C7–C12 aralkylene radical;
• R7 and R7′, independently of each other, are hydrogen, C1–C4 alkyl or halogen;
• and
• Q is a radical of formula (5)
• wherein q is the number 0 or 1,
• each of R8 and R9 independently of the other is hydrogen, C1–C4 alkyl, phenyl, carboxy or halogen,
• R10 is hydrogen, C1–C4 alkyl or halogen, and
• Z′ is a linear or branched C1–C12 alkylene, an unsubstituted phenylene, an C1–C4 alkyl- or C1–C4 alkoxy-substituted phenylene, or a C7–C12 aralkylene.