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AssigneeElf Atochem S.A.
InventorsPhilippe Heim, Bruno Vuillemin, Philippe Teyssie, Philippe Bayard, Jinshan Wang
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Thermoplastic, elastomeric, conjugated diene (e.g., butadiene)/methyl methacrylate block copolymers having elevated Tg and improved impact strength, well suited as polymer impact strength-modifiers and for conversion into pressure-sensitive adhesives, are prepared by (a) anionically polymerizing a conjugated diene monomer in an apolar solvent medium to provide a living polydiene, (b) next adding an alkali metal alkoxyalcoholate ligand to the medium comprising the living polydiene thus formed, (c) block copolymerizing the step (b) living polydiene with methyl methacrylate comonomer to provide a living copolymer, and (d) reacting the step (c) living copolymer with at least one protonic compound, e.g., water, alcohol and/or acid, and completing the polymerization thereof, with the proviso that polymerization of the conjugated diene and the methyl methacrylate comonomers is strictly carried out in the apolar solvent medium, in particular in toluene, benzene or ethylbenzene.
A process for the preparation of a thermoplastic, elastomeric, conjugated diene/methyl methacrylate block copolymer having improved heat resistance, comprising (a) anionically polymerizing a conjugated diene monomer in an apolar solvent medium to provide a living polydiene, (b) next adding an alkali metal alkoxyalcoholate ligand to the medium comprising the living polydiene thus formed, (c) block copolymerizing the step (b) living polydiene with methyl methacrylate comonomer, also in said apolar solvent medium, to provide a living copolymer, and (d) reacting the step (c) living copolymer with at least one protonic compound and completing the polymerization thereof, with the proviso that polymerization of said conjugated diene and said methyl methacrylate comonomers is carried out essentially exclusively in said apolar solvent medium.
A process for the preparation of a thermoplastic, elastomeric, conjugated diene/methyl methacrylate block copolymer having improved heat resistance, which comprises (a) anionically polymerizing a conjugated diene monomer in an apolar solvent medium to provide a living polydiene, (b) next adding a ligand of formula ROM to the medium comprising said living polydiene, in which M is an alkali metal and R is a radical R.sup.1 (OR.sup.2).sub.m wherein R.sup.1 is a linear or branched alkyl, arylalkyl or alkylaryl radical, the alkyl moiety of which having from 1 to 6 carbon atoms, R.sup.2 is a linear or branched alkylene radical having from 2 to 4 carbon atoms and m is an integer 1, 2 or 3, (c) reacting the step (b) living polydiene with methyl methacrylate comonomer, also in said apolar solvent medium, to provide a living copolymer, and then (d) reacting the step (c) living copolymer with at least one protonic compound and completing the polymerization thereof, with the proviso that polymerization of said conjugated diene and said methyl methacrylate comonomers is carried out essentially exclusively in said apolar solvent medium.
Dependencies are inferred from the claim text.