Diene coupled copolymers rich in ethylene units and preparation method thereof
AssigneeCompagnie Generale Des Etablissements Michelin
InventorsRobert NGO, François JEAN-BAPTISTE-DIT-DOMINIQUE, Karine VERNAY
Life of this patent
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Abstract
A copolymer of a 1,3-diene and of an olefin which contains more than 50 mol % of ethylene units is provided. The olefin is ethylene or a mixture of ethylene and of an α-monoolefin. The copolymer is a coupled copolymer, and the chains of the copolymer are connected to one another by a group containing at least two units of formula 1, —(CH2—CH(CH3)—CO—O)—. Each copolymer chain is bonded to a distinct unit of formula 1 via a covalent bond between a carbon atom of a monomer unit of the copolymer chain and the carbon atom of the methylene group of the unit of formula 1.
Claims17
A copolymer, comprising:
- a 1,3-diene and an olefin, the olefin being ethylene or a mixture of ethylene and an α-monoolefin, wherein the copolymer contains more than 50 mol % of ethylene units and is a coupled copolymer, chains of the copolymer being connected to one another by a group containing at least two units of formula 1
- each copolymer chain being bonded to a distinct unit of formula 1 via a covalent bond between a carbon atom of a monomer unit of the copolymer chain and the carbon atom of a methylene group of the unit of formula 1.
A process for preparing a coupled copolymer of a 1,3-diene and of an olefin, the copolymer containing more than 50 mol % of ethylene units, wherein the process comprises successive stages a), b) and c),
- stage a) being a polymerization of a monomer mixture containing a 1,3-diene and an olefin in the presence of a catalytic system based at least on a metallocene of formula (Ia) and on an organomagnesium compound, cocatalyst,
- Cp1 and Cp2, which are identical or different, being selected from the group consisting of fluorenyl groups, cyclopentadienyl groups and indenyl groups, the groups being substituted or unsubstituted,
- P being a group bridging the two groups Cp1 and Cp2, and comprising a silicon or carbon atom,
- Nd denoting the neodymium atom,
- L representing an alkali metal selected from the group consisting of lithium, sodium and potassium,
- N representing a molecule of an ether,
- x, which is or is not an integer, being equal to or greater than 0,
- y, which is an integer, being equal to or greater than 0,
- the olefin being ethylene or a mixture of ethylene and of an α-monoolefin,
- stage b) being the reaction of a coupling agent, a compound containing at least two methacrylate functions of formula CH2═C(CH3)CO—O—, with the reaction product of the polymerization of stage a), and
- stage c) being a chain termination reaction.
Dependencies are inferred from the claim text.