Hot melt adhesive composition for labels
AssigneeEnichem Elastomeri S.r.l.
InventorsSergio Giordano, Antonio Gurnari, Carla Parodi, Giantommaso Viola
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Abstract
A block copolymer composition is disclosed which derives from the copolymerization of a monoalkenyl-arene and a conjugated diene having from 4 to 5 carbon atoms, and comprising: from 30% to 55% by weight, preferably from 34% to 50%, of non-coupled linear structures; from 25% to 40% by weight, preferably from 30% to 35% by weight, of coupled linear structures; from 20% to 40% by weight, preferably from 24% to 35% by weight, of branched structures. The preparation of said composition and its use in the formulation of adhesive tapes and labels are disclosed as well.
Claims19
A block copolymer composition prepared by copolymerizing a monoalkenyl-arene and a conjugated diene having from 4 to 5 carbon atoms, comprising:
- (a) a linear, non-coupled block copolymer of the formula A--B, in an amount comprised within the range of from 30 to 55% by weight;
- (b) a linear, coupled block copolymer of the formula (A--B).sub.n --X, (B.sub.1 --A--B.sub.2)--X, and (B.sub.1 TA--B.sub.2).sub.n --X where n=2, in an amount comprised within the range of from 25% to 40% by weight;
- and
- (c) a branched, coupled block copolymer of the formula (A--B).sub.n --X, (B.sub.1 --A--B.sub.2).sub.n --X, and (B.sub.1 TA--B.sub.2).sub.n --X wherein n.gtoreq.3 and in an amount comprised within the range of from 20% to 40% by weight;
- wherein A is a polymer block of said monoalkenyl-arene, B is a polymer block of said conjugated diene, T is a random copolymer segment of said monoalkenyl-arene and said conjugated diene, and X in (b) and (c) is an organic radical derived from coupling agents selected from monobromo-derivatives having the formula R.sub.1 --Br in which R.sub.1 is a monofunctional C.sub.1 -C.sub.10 hydrocarbyl radical selected from the group consisting of alkyl, cycloalkyl and aryl radicals, and wherein the total percent of said (a), (b) and (c) is equal to one hundred %.
An adhesive composition for preparing adhesive tapes and labels, comprising a base polymer, one or more tackifier resins and, optionally, one or more antioxidants and a fluidifier resin and/or a fluidifier oil, characterized in that said base polymer is a composition of block copolymers derived from the copolymerization of a monoalkenyl-arene and a conjugated diene having from 4 to 5 carbon atoms, with the above said copolymer composition consisting essentially of:
- (a) a linear, non-coupled block copolymer of the formula A--B in an amount comprised within the range of from 30% to 55% by weight;
- (b) a linear, coupled block copolymer of the formula (A--B).sub.n --X, (B.sub.1 --A--B.sub.2)--X, and (B.sub.1 TA--B.sub.2).sub.n --X where n=2, in an amount comprised within the range of from 25% to 40% by weight;
- and
- (c) a branched, coupled block copolymer of the formula (A--B).sub.n --X, (B.sub.1 --A--B.sub.2).sub.n --X, and (B.sub.1 TA--B.sub.2).sub.n --X wherein n.gtoreq.3 and in an amount comprised within the range of from 20% to 40% by weight;
- wherein A is a polymer block of said monoalkenyl-arene, B is a polymer block of said conjugated diene, T is a random copolymer segment of said monoalkenyl-arene and said conjugated diene, and X in (b) and (c) is an organic radical derived from coupling agents selected from monobromo-derivatives having the formula R.sub.1 --Br in which R.sub.1 is a monofunctional C.sub.1 -C.sub.10 hydrocarbyl radical selected from the group consisting of alkyl, cycloalkyl and aryl radicals, and wherein the total percent of said (a), (b) and (c) is equal to one hundred %.
Dependencies are inferred from the claim text.