Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
287 words
In a continuous process for the stereoregular polymerization of isoprene monomer, containing α-acetylenes and cyclopentadiene impurities, wherein the isoprene monomer is (a) initially subjected to dehydration, (b) charged to the first in a series of reactors containing a solvent for said monomer and a catalyst directive for the stereoregular polymerization of said monomer to cis-1,4 poly(isoprene), (c) the contents of (b) transferred from the first reactor to a downstream reactor where the isoprene is polymerized further, (d) the polymerization terminated prior to conversion of all of said monomer to cis-1,4 poly(isoprene) by contacting the catalyst with a "short-stop" agent, (e) separating the unpolymerized monomer from the cis-1,4 poly(isoprene), (f) replacement of the monomer converted to polymer by the addition of "make-up" isoprene, containing α-acetylene and cyclopentadiene impurities, to the isoprene monomer recovered in step (e), and (g) repeating steps (a) to (f) in sequence at least one additional time, the improvement comprising: adding pre-dried "make-up" isoprene, containing α-acetylenes and cyclopentadiene impurities, to a charge containing actively polymerizing isoprene monomer, cis-1,4 poly(isoprene) and catalyst which is directive for the stereoregular polymerization of said monomer to cis-1,4 poly(isoprene), said "make-up" isoprene being added to the last of the series of reactors and in sufficient quantities to replace substantially all of the isoprene monomer contemplated for conversion to polymer; and deactivating the polymerization catalyst subsequent to the addition of the "make-up" isoprene to the charge by contacting said catalyst with a "short-stop" agent, the interval between addition of the "make-up" isoprene to the actively polymerizing monomer and subsequent deactivation of the catalyst being sufficient to allow for the scavenging of substantially all of the α-acetylenes and at least 50% of the cyclopentadiene impurities from the "make-up" isoprene by said catalyst.
Claim 2
Dependent Claim
287 words
In a continuous process for the stereoregular polymerization of isoprene monomer, containing α-acetylenes and cyclopentadiene impurities, wherein the isoprene monomer is (a) initially subjected to dehydration, (b) charged to the first in a series of reactors containing a solvent for said monomer and a catalyst directive for the stereoregular polymerization of said monomer to cis-1,4 poly(isoprene), (c) the contents of (b) transferred from the first reactor to a downstream reactor where the isoprene is polymerized further, (d) the polymerization terminated prior to conversion of all of said monomer to cis-1,4 poly(isoprene) by contacting the catalyst with a "short-stop" agent, (e) separating the unpolymerized monomer from the cis-1,4 poly(isoprene), (f) replacement of the monomer converted to polymer by the addition of "make-up" isoprene, containing α-acetylene and cyclopentadiene impurities, to the isoprene monomer recovered in step (e), and (g) repeating steps (a) to (f) in sequence at least one additional time, the improvement comprising: adding pre-dried "make-up" isoprene, containing α-acetylenes and cyclopentadiene impurities, to a charge containing actively polymerizing isoprene monomer, cis-1,4 poly(isoprene) and catalyst which is directive for the stereoregular polymerization of said monomer to cis-1,4 poly(isoprene), said "make-up" isoprene being added to the last of the series of reactors and in sufficient quantities to replace substantially all of the isoprene monomer contemplated for conversion to polymer; and deactivating the polymerization catalyst subsequent to the addition of the "make-up" isoprene to the charge by contacting said catalyst with a "short-stop" agent, the interval between addition of the "make-up" isoprene to the actively polymerizing monomer and subsequent deactivation of the catalyst being sufficient to allow for the scavenging of substantially all of the α-acetylenes and at least 50% of the cyclopentadiene impurities from the "make-up" isoprene by said catalyst.
Claim 3
Dependent Claim
32 words
The improved process of claim 1, wherein the amount of "make-up" isoprene added to the charge represents less than 50% by weight of the total isoprene monomer content of the initial charge.
Claim 4
Dependent Claim
14 words
The improved process of claim 1, wherein the catalyst is of the coordination type.
Claim 5
Dependent Claim
16 words
The improved process of claim 1, wherein the catalyst comprises a reduced form of titanium tetrachloride.
Claim 6
Dependent Claim
14 words
The improved process of claim 1, wherein the catalyst comprises an alkyl lithium compound.
Claim 7
Dependent Claim
27 words
The improved process of claim 1, wherein the level of impurity in the isoprene monomer is in excess of that normally found in polymerization grade isoprene monomer.
Claim 8
Dependent Claim
32 words
The improved process of claim 1, wherein the amount of "make-up" isoprene added to the charge represents less than 75% by weight of the total isoprene monomer content of the initial charge.