Process for producing continuously tapered polymers and copolymers and products produced thereby
AssigneeBridgestone/Firestone, Inc.
InventorJames E. Hall
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Abstract
A process for preparing continuously tapered polymers and copolymers having a continuous change in microstructure along the polymer backbone is disclosed. The process produces polymers and copolymers with multiple glass transition temperatures of very small energy absorption, i.e. no definable glass transition temperature. The polymers have a flexible chain end and they progressively become stiffer along the length of the chain.
Claims21
A process for preparing a continuously tapered polymer from reactive monomers comprising 40 to 100 parts by weight of one or more conjugated diene monomers and from 0 to 60 parts by weight of one or more vinyl aromatic monomers comprising continuously or incrementally injecting said reactive monomers into a reaction vessel in the presence of an anionic initiator and continuously or incrementally increasing the amount of a randomizing modifier at a rate sufficient to produce a tapered polymer having no clear T.sub.g as determined by DSC said randomizing modifier comprising a 1,2-microstructure controlling agent contacting said monomers and polymerizing said monomers into a tapered polymer.
A process for preparing a continuously tapered polymer from reactive monomers said polymer comprising 40 to 100 parts by weight of one or more conjugated diene monomers and from 0 to 60 parts by weight of one or more vinyl aromatic monomers comprising continuously or incrementally injecting diene monomers and vinyl aromatic monomers in an increasing ratio of vinyl aromatic monomers to diene monomers into a reaction vessel in the presence of an anionic initiator and polymerizing said monomers into a tapered polymer wherein said ratio is increased at a rate sufficient to produce a tapered polymer having no clear T.sub.g as determined by DSC.
A polybutadiene polymer having an average 1,2-microstructure ranging from about 15 to 40 percent and a chain length comprising a first 30 percentile and a terminal 30 percentile, wherein the first 30 percentile of the chain length has an average 1,2-microstructure of at least 20 percent lower than the average 1,2-microstructure of the terminal 30 percentile of the chain length.
A continuously tapered copolymer prepared by anionic polymerization having the structure:
- A-(B/S)-C
- wherein A represents a block formed from diene monomers, B/S represents a continuously tapered block formed from vinyl aromatic monomers and diene monomers wherein the vinyl aromatic monomer contributed units and percentage of 1,2-microstructure continuously increase along the length of the chain, and C represents a block of 1,3-diene and vinyl aromatic monomer and wherein the continuously tapered copolymer has no clear glass transition temperature as determined by DSC, and A and C each constitute 20 percent or less by weight of the tapered copolymer.
A process for preparing a continuously tapered polymer from reactive monomers said tapered polymer comprising 40 to 100 parts by weight of one or more conjugated diene monomers and from 0 to 60 parts by weight of one or more vinyl aromatic monomers comprising continuously or incrementally injecting diene monomers and vinyl aromatic monomers in an increasing ratio of diene monomers to vinyl aromatic monomers into a reaction vessel in the presence of an anionic initiator and a 1,2-microstructure controlling agent and polymerizing said monomers into a tapered polymer having no clear Tg as determined by DSC wherein said tapered polymer comprises 60 to 100 percent by weight of vinyl aromatic monomer contributed units in an initial block and 0 to 20 percent by weight of vinyl aromatic monomer contributed units in a terminal block.
Dependencies are inferred from the claim text.