Promoters in the polymerization of monovinyl-aromatic compounds with primary lithium initiators
AssigneePhillips Petroleum Company
InventorDaniel H. Willis
Life of this patent
Estimating the term…
Abstract
1,1-DIALKYLETHYLENES, SUCH AS ISOBUTENE, PROMOTE THE PRIMARY LITHIUM INITIATED POLYMERIZATION OF MONOVINYL-AROMATIC COMPOUNDS, SUCH AS STYRENE, EITHER IN HOMOPOLYMERIZATIONS, OR IN THE FORMATION OF A-B-A block copolymers or (A-B).sub.a Z radial block copolymers, such as by sequential monomer addition with conjugated dienes.
Claims21
A process for the preparation of a block copolymer which comprises the steps of
- polymerizing under solution polymerization conditions a first monomer charge selected from monovinyl-substituted aromatic hydrocarbons of 8 to 12 carbon atoms per molecule employing a primary hydrocarbyl lithium initiator and a 1,1-dialkylethylene promoter of the formula ##STR2## wherein each R is hydrogen, methyl, or ethyl, effective to promote the polymerization of said first monomer with said primary hydrocarbyl lithium initiator, employing a ratio of said promoter:primary hydrocarbyl lithium initiator in the range of about 50:1 to 7500:1,
- thereafter, after substantially complete polymerization of said first monovinyl-substituted aromatic hydrocarbon and prior to termination adding to the polymerization admixture a second monomer charge selected from conjugated dienes of 4 to 12 carbon atoms per molecule, and polymerizing said so added conjugated diene monomer,
- thereafter, prior to termination, adding to the polymerization admixture a polyfunctional treating agent in an amount in the range of about 0.1-1.5 equivalents per equivalent of lithium, thereby preparing a coupled branched polymer, wherein the weight ratio of polymerization first monomer:second monomer is in the range of about 10-50:90-50.
A process which comprises polymerizing at least one first monomer which is a polymerizable monovinyl-substituted aromatic compound monomer with a primary hydrocarbyl lithium polymerization initiator and a 1,1-dialkylethylene promoter under solution polymerization conditions of temperature and pressure, wherein said process employs an amount of said promoter effective to promote said polymerization of said monovinyl-substituted aromatic monomer with primary hydrocarbyl lithium initiator, and said 1,1dialkylethylene promoter contains up to 8 carbon atoms per molecule,
- after substantially complete polymerization of said first monomer and prior to termination, polymerizing at least one second monomer which is a polymerizable conjugated diene monomer, and polymerizing said conjugated diene monomer to substantially complete conversion, and
- thereafter and prior to termination adding to the resulting polymerization admixture a polyfunctional treating agent in an effective coupling amount, wherein said polyfunctional treating agent is a polyepoxide, polyisocyanate, polyamine, polyaldehyde, polyketone, polyanhydride, polyester, polyhalide, polyvinyl aromatic, carbon monoxide, carbon dioxide, or monoester, and wherein the functionality of said polyfunctional treating agent is at least two.
A process which comprises
- polymerizing at least one polymerizable monovinyl-substituted aromatic compound with a primary hydrocarbyl lithium polymerization initiator and a 1,1-dialkylethylene promoter under solution polymerization conditions of temperature and pressure, wherein said process employs an amount of said promoter effective to promote said polymerization of said monovinyl-substituted aromatic compound with said primary hydrocarbyl lithium initiator, and said 1,1-dialkylethylene promoter contains up to 8 carbon atoms per molecule,
- adding to the polymerization admixture at least one polymerizable conjugated diene monomer, after substantially complete polymerization of said monovinyl-substituted aromatic compound and prior to termination, and polymerizing said conjugated diene monomer to substantially complete conversion, and
- adding to said polymerization admixture prior to termination a polyfunctional treating agent selected from polyhalides in an effective coupling amount, wherein the functionality of said polyfunctional treating agent is at least two, thereby preparing a coupled polymer.
Dependencies are inferred from the claim text.