CA1226398A - Chain terminators for polyvinyl chloride polymerization - Google Patents
Chain terminators for polyvinyl chloride polymerizationInfo
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- CA1226398A CA1226398A CA000406483A CA406483A CA1226398A CA 1226398 A CA1226398 A CA 1226398A CA 000406483 A CA000406483 A CA 000406483A CA 406483 A CA406483 A CA 406483A CA 1226398 A CA1226398 A CA 1226398A
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- tert
- carbon atoms
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
- C08F2/42—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation using short-stopping agents
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F14/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
- C08F14/02—Monomers containing chlorine
- C08F14/04—Monomers containing two carbon atoms
- C08F14/06—Vinyl chloride
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- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polymerisation Methods In General (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
CHAIN TERMINATORS FOR POLYVINYL CHLORIDE POLYMERIZATION
Abstract of the Disclosure An improved process for terminating the suspension polymerization reaction of vinyl chloride monomer into polyvinyl chloride which comprises adding hindered phenols of the structure presented hereinafter to the polymerization reaction at a point in time when a predetermined amount of monomer conversion has occured.
Abstract of the Disclosure An improved process for terminating the suspension polymerization reaction of vinyl chloride monomer into polyvinyl chloride which comprises adding hindered phenols of the structure presented hereinafter to the polymerization reaction at a point in time when a predetermined amount of monomer conversion has occured.
Description
3~
The basic process of vinyl polymerization involves the addition of a vinyl monomer to a growing polymer chain. The polymerization is conducted at the proper temperature under pressure in the presence of an initiator. The polymer chain continues to grow in length until it is terminated by some means.
With regard to vinyl chloride polymerization, the overwhelming amount of polyvinyl chloride is prepared by suspension polymerization.
In this process, the vinyl chloride monomer and an initiator are dispersed by agitation into a water phase at proper temperature and pressure. Suspending agents such as methyl or ethyl cellulose, gelatin, polyvinyl alcohol or other water-soluble polymers are utilized to stabilize the suspension during the polymerization reaction. The fine granules of polymer in the form of a slurry are discharged from the reactor and centrifuged or filtered to remove the water. Thorough washing and drying of the polymer to remove traces of the suspension stabilizer and the reaction medium conclude the procedure.
Toward the end of the polymerization cycle the pressure in the system begins to drop, followed very shortly by a peak in the polymerization rate. Beyond the peak, the rate begins to drop sharply and the polymer beads become less porous as the free monomer is absorbed into the polymer. Such change in the particle character, both in terms of porosity and particle size distribution, is disadvantageous to the manufacturer in terms of reduced performance and economy of production. Thus the crenulated porous surface is desired for enhanced plasticizer uptake to form dry blends for various extnlding or calendaring operations. In order to avoid such adverse effects, the manufacturer will terminate the polymerization reaction prior to complete monomer conversion. The :~2~
experience of the manufacturer will best determine the point at which polymerization is terminated to give high quality polymer, although 70 to 90% conversion reflects a general termination point.
Various techniques have been adopted for terminating polymerization.
A purely mechanical approach has involved discharging the polymer slurry into an evacuated stripper tank and quickly reducing the temperature and pressure to effectively stop polymerization.
Various chemical approaches have also been adopted. The numerous conventional chemical means for terminating vinyl polymerization re-actions are detailed in chemical texts and publications. More recent approaches have involved adding terminating agents or chain terminators to halt free radical propagation, removing unreactecl monomer and processing the converted slurry to obtain the dry poly-vinyl chloride. Thus, compounds such as methyl styrene, bisphenol A
and various hindered phenol antioxidants have been added to the reactant mix at a pre-determined point for purposes of chain ter-mination. Among these compounds, 2,6-di-tert-butyl-4-methylphenol, i.e. BHT, has been most frequently utilized as a chain terminator by addition to the polymerization system at the desired termination point. Various other hindered phenols having tertiary butyl sub-stituents in the 2- and 6-positions on the benzene ring have also been used for this purpose. The performance results have, however, been less than desirable with these hindered phenols, these materials having little effect when added in concentrations up to about 250 ppm. BHT has also exhibited this limitation in being unable to provide effective chain termination at the lower, more desirable concentration ranges.
A further PVC chain termination composition based on hindered phenols is disclosed in U.S. 4,229,598. This composition is pre-pared by the alkylation of a fractionation cut from the product of 3~
vapvr phase methylation of phenol. The fraction that is alkylated is a specific mixture of cresylic acids resulting in a corresponding mixture of simple methyl-t-butyl phenols. These mixtures are necessarily prepared, however, by rather complex and demanding procedures.
It is thereEore the primary object oE this invention to modify vinyl chloride suspension polymerization reactions so as to increase the efficiency of the chain termination step.
It is another object to define a class of additives which when added to the polymerization system provides the above noted increased effectiveness.
It is still another object to define the parameters of this improved polymerization procedure.
Various other objects and advantages of this invention will be readily apparent from the following detailed description thereof.
It has been surprisingly found that effectiveness of chain termina-tion in vinyl chloride suspension polymerizations can be signifi-cantly increased by the addition of a class of hindered phenols having a methyl group on or associated with the phenyl ring, and preferably in the ortho or meta-position on the ring, to the poly-merization reaction system at a point in time when a designated amount of monomer has been converted. Thus, the presence of the methyl group, preferably as a substitute for one of the tertiary butyl groups generally shielding the phenolic group in the prior art materials, results in an immediate termination of the polymerization reaction. In this manner, rapid chain termination is effected thereby facilitating the porduction of high quality polyvinyl chloride in high yields. Tlese results are achieved without any significant modification of the suspension polymerization reaction and without any concurrent adverse effects. These chain terminators perform substantially better than the prior art materials in providing rapid and total chain termination and in providing these improved performance characteristics at significantly reduced concentration levels. Since these phenolic materials are recognized antioxidants and heat stabilizers for polymeric systems, their addition to the polymerization reaction effectively stops free radical propagation while correspondingly providing high levels of stability to the resulting polyvinyl chloride. In addition, approxi-mately 90-95% of the chain stopper remains in the resin after stripping and/or drying, thereby effectively eliminating contamina-tion of the recovered monomer. In contrast, lower molecular weight materials such as BHT can be expected to come off with the excess monomer in the gaseous stream so as to contaminate the monomer and therefore inhibit any polymerization reaction wherein the re-cycled monomer is utilized.
The chain terminators applicable for use in the process of this invention correspond to the formulae (I) RX~(CaH2a)~Q
wherein R is 3\
\ / x 2x is oxygen or sulfur, a is an integer from 6 to 30, x is an integer from O to 6, ~Z2~3~
Rl is alkyl of from l to 8 carbon atoms, Q is hydrogen or -A-(C H2 )-R2~
A is oxygen, sulfur, -N- or -C-y is an integer from 0 to 20, B is alkyl of from 1 to 6 carbon atoms or alkanoyl of from 1 to 6 carbon atoms, R2 is hydrogen, hydroxy, alkanoyloxy of from l to 6 carbon atoms or 5\ 0 H0- (C H )-C- , and R3, R4, R5 and R6 independently are alkyl from 1 to 8 carbon atoms;
(II) RX [(CbH2b) Y~d-- 7 wherein R and X are as previously defined, b is an integer from 2 to 6, d is an integer from 3 to 40, Y is oxygen or sulfur, and R7 is hydrogen, alkyl of from 1 to 6 carbon atoms or 5\
0--\ / (CxH2x : with R5, R6 and x being as previously defined;
(III) 1,1,3-~ris-(2-methyl-4-hydroxy-5-tert.-butylphenyll)-butane ; or (IV) 1,3,5-tris-(2,6-dimethyl-3-hydroxy-4-tert.-butylbeenzyl)-isocyanurate.
!
3~3~
Compounds of formula I which are preferred exhibit X as oxygen, x as 0 tc- 2, Rl as alkyl of from 1 to 4 carbon atoms, A as oxygen, y as 0 to 2, R2 as hydrogen or the indicated phenol and R5 and R6 as alkyl of frc,m 1 to 4 carbon atoms. Particularly preferred are those compounds wherein Rl and R6 are tert.-butyl positioned in the ortho-position, R5 is methyl and x is 2.
Specific compounds of preference are octadecyl 3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate and 1,6-hexanediol bis-3-~3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate.
Compounds of formula II which are preferred exhibit X and Y as oxygen, x as 0 to 2, Rl as al~yl of from 1 to 4 carbon atoms, b as
The basic process of vinyl polymerization involves the addition of a vinyl monomer to a growing polymer chain. The polymerization is conducted at the proper temperature under pressure in the presence of an initiator. The polymer chain continues to grow in length until it is terminated by some means.
With regard to vinyl chloride polymerization, the overwhelming amount of polyvinyl chloride is prepared by suspension polymerization.
In this process, the vinyl chloride monomer and an initiator are dispersed by agitation into a water phase at proper temperature and pressure. Suspending agents such as methyl or ethyl cellulose, gelatin, polyvinyl alcohol or other water-soluble polymers are utilized to stabilize the suspension during the polymerization reaction. The fine granules of polymer in the form of a slurry are discharged from the reactor and centrifuged or filtered to remove the water. Thorough washing and drying of the polymer to remove traces of the suspension stabilizer and the reaction medium conclude the procedure.
Toward the end of the polymerization cycle the pressure in the system begins to drop, followed very shortly by a peak in the polymerization rate. Beyond the peak, the rate begins to drop sharply and the polymer beads become less porous as the free monomer is absorbed into the polymer. Such change in the particle character, both in terms of porosity and particle size distribution, is disadvantageous to the manufacturer in terms of reduced performance and economy of production. Thus the crenulated porous surface is desired for enhanced plasticizer uptake to form dry blends for various extnlding or calendaring operations. In order to avoid such adverse effects, the manufacturer will terminate the polymerization reaction prior to complete monomer conversion. The :~2~
experience of the manufacturer will best determine the point at which polymerization is terminated to give high quality polymer, although 70 to 90% conversion reflects a general termination point.
Various techniques have been adopted for terminating polymerization.
A purely mechanical approach has involved discharging the polymer slurry into an evacuated stripper tank and quickly reducing the temperature and pressure to effectively stop polymerization.
Various chemical approaches have also been adopted. The numerous conventional chemical means for terminating vinyl polymerization re-actions are detailed in chemical texts and publications. More recent approaches have involved adding terminating agents or chain terminators to halt free radical propagation, removing unreactecl monomer and processing the converted slurry to obtain the dry poly-vinyl chloride. Thus, compounds such as methyl styrene, bisphenol A
and various hindered phenol antioxidants have been added to the reactant mix at a pre-determined point for purposes of chain ter-mination. Among these compounds, 2,6-di-tert-butyl-4-methylphenol, i.e. BHT, has been most frequently utilized as a chain terminator by addition to the polymerization system at the desired termination point. Various other hindered phenols having tertiary butyl sub-stituents in the 2- and 6-positions on the benzene ring have also been used for this purpose. The performance results have, however, been less than desirable with these hindered phenols, these materials having little effect when added in concentrations up to about 250 ppm. BHT has also exhibited this limitation in being unable to provide effective chain termination at the lower, more desirable concentration ranges.
A further PVC chain termination composition based on hindered phenols is disclosed in U.S. 4,229,598. This composition is pre-pared by the alkylation of a fractionation cut from the product of 3~
vapvr phase methylation of phenol. The fraction that is alkylated is a specific mixture of cresylic acids resulting in a corresponding mixture of simple methyl-t-butyl phenols. These mixtures are necessarily prepared, however, by rather complex and demanding procedures.
It is thereEore the primary object oE this invention to modify vinyl chloride suspension polymerization reactions so as to increase the efficiency of the chain termination step.
It is another object to define a class of additives which when added to the polymerization system provides the above noted increased effectiveness.
It is still another object to define the parameters of this improved polymerization procedure.
Various other objects and advantages of this invention will be readily apparent from the following detailed description thereof.
It has been surprisingly found that effectiveness of chain termina-tion in vinyl chloride suspension polymerizations can be signifi-cantly increased by the addition of a class of hindered phenols having a methyl group on or associated with the phenyl ring, and preferably in the ortho or meta-position on the ring, to the poly-merization reaction system at a point in time when a designated amount of monomer has been converted. Thus, the presence of the methyl group, preferably as a substitute for one of the tertiary butyl groups generally shielding the phenolic group in the prior art materials, results in an immediate termination of the polymerization reaction. In this manner, rapid chain termination is effected thereby facilitating the porduction of high quality polyvinyl chloride in high yields. Tlese results are achieved without any significant modification of the suspension polymerization reaction and without any concurrent adverse effects. These chain terminators perform substantially better than the prior art materials in providing rapid and total chain termination and in providing these improved performance characteristics at significantly reduced concentration levels. Since these phenolic materials are recognized antioxidants and heat stabilizers for polymeric systems, their addition to the polymerization reaction effectively stops free radical propagation while correspondingly providing high levels of stability to the resulting polyvinyl chloride. In addition, approxi-mately 90-95% of the chain stopper remains in the resin after stripping and/or drying, thereby effectively eliminating contamina-tion of the recovered monomer. In contrast, lower molecular weight materials such as BHT can be expected to come off with the excess monomer in the gaseous stream so as to contaminate the monomer and therefore inhibit any polymerization reaction wherein the re-cycled monomer is utilized.
The chain terminators applicable for use in the process of this invention correspond to the formulae (I) RX~(CaH2a)~Q
wherein R is 3\
\ / x 2x is oxygen or sulfur, a is an integer from 6 to 30, x is an integer from O to 6, ~Z2~3~
Rl is alkyl of from l to 8 carbon atoms, Q is hydrogen or -A-(C H2 )-R2~
A is oxygen, sulfur, -N- or -C-y is an integer from 0 to 20, B is alkyl of from 1 to 6 carbon atoms or alkanoyl of from 1 to 6 carbon atoms, R2 is hydrogen, hydroxy, alkanoyloxy of from l to 6 carbon atoms or 5\ 0 H0- (C H )-C- , and R3, R4, R5 and R6 independently are alkyl from 1 to 8 carbon atoms;
(II) RX [(CbH2b) Y~d-- 7 wherein R and X are as previously defined, b is an integer from 2 to 6, d is an integer from 3 to 40, Y is oxygen or sulfur, and R7 is hydrogen, alkyl of from 1 to 6 carbon atoms or 5\
0--\ / (CxH2x : with R5, R6 and x being as previously defined;
(III) 1,1,3-~ris-(2-methyl-4-hydroxy-5-tert.-butylphenyll)-butane ; or (IV) 1,3,5-tris-(2,6-dimethyl-3-hydroxy-4-tert.-butylbeenzyl)-isocyanurate.
!
3~3~
Compounds of formula I which are preferred exhibit X as oxygen, x as 0 tc- 2, Rl as alkyl of from 1 to 4 carbon atoms, A as oxygen, y as 0 to 2, R2 as hydrogen or the indicated phenol and R5 and R6 as alkyl of frc,m 1 to 4 carbon atoms. Particularly preferred are those compounds wherein Rl and R6 are tert.-butyl positioned in the ortho-position, R5 is methyl and x is 2.
Specific compounds of preference are octadecyl 3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate and 1,6-hexanediol bis-3-~3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate.
Compounds of formula II which are preferred exhibit X and Y as oxygen, x as 0 to 2, Rl as al~yl of from 1 to 4 carbon atoms, b as
2, d as 3 to 20, R7 as the indicated phenol and R5 and R6 as alkyl of from 1 to 4 carbon atoms Particularly preferred are those com-pounds wherein Rl and R6 are tert.-butyl positioned in the ortho-position and R5 is methyl. A specific compound of preference is triethylene glycol bis-3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-prop;onate.
,, ~2639~3 ~lethods for preparing tllese hindered phenols are well known to those skilled in the art. Specific reference is made to U.S.
Patents 3,2851855, 3,944~594 and 4,032,562 for information re-garding the phenols of formulae I and II and their methods of preparation. In general, they are prepared,from the appropriate acids, acid chlorides or lower alkyl esters and alcohols or thio alcohols utilizing well-l;nown esterification or transesterification methods.
As previously noted, these hindered phenols are known for their antioxidant activity in a variety of polymeric substances including polyvinyl chloride. When added to such polymers for purposes of this area of utility, they are generally added to the final polymeric product.
~Tinyl chloride suspension polymerization techniques are likewise well-knonw to those skilled in the art. Such techniques are described in detail in most basic polymer chemistry texts such, for example, as W. Sorenson, "Preparative Methods of Polymer Chemistry", Second Ed., Interscience Publishers, N.~. (196S). In general, the reactor is charged with the appropriate amounts of suspending agent, initiator and emulsifier in the aqueous reaction system. Typical suspending agents include methyl or ethyl cellulose, gelatin, polyvinyl alcohol or other water soluble polymers, while typical initiators include peroxydicarbonate, benzoyl peroxide, lauroyl peroxide, t-butylperbenzoate, acetyl peroxide, cumene hydroperoxide, di-t-butyl peroxide, and the like. The emulsifier is generally added to enhance the porosity of the polymer particles.
' I'.' ,',~
9~3 This charge is generally added to the reactor at ambient temperature.
The vinyL chloride monomer is then introduced, agitation is ini-tiated and the reactor is heated to the polymerization range of from 45 to 60C. The pressure will be in the range of from about 140-150 psi for the 5-7 hour reaction period necessary to achieve about 70% monomer conversion, with the residual monomer being recovered for possible future use. Filtration washing ancl drying complete the polymerization procedure.
In addition to the chemical structure of the instant chain terminators, effective termination is dependent upon the amount of compound added. or purposes of this invention, 25-5000 ppm of hindered phenol, based on the weight of the vinyl chloride monomef9 added at the time of 0 to 95% monomer conversion will provide the desired benefits. Preferred values are 50-1000 ppm of hindered phenol added at 70 to 90% monomer conversion, while particularly preferred concentrations are 50-500 ppm of hindered phenol.
It is to be noted that the latter 70-90% range is the desired range for obtaining commercially acceptable yields of polymer. Howevera the instant hindered phenols will terminate the polymerization reaction at any stage thereof. Accordingly, the 0-95% range reflects the possibility of premature termination where emergency conditions, power outages, and the like, demand such early termination.
The rate of polymerization can be designated in terms of the time to the designated amount of conversion of the polymerization reaction and/or the amount of pressure drop after conversion, the latter being especially indicative of termination capability. In this context, "conversion" is designated as the point during polymeri-zation when vinyl chloride monomer is no longer available as a free monomer and is absorbed into the polymer.
The compounds designated herein are secn to provide immediate termination of vinyl chloride polymerization reactions. This irnmdediate termination alloys for the production of high yields of high quality polyvinyl chloride. These compounds are also seen to provide such rapid termination at concentration levels substantially below that required for currently utilized materials.
The compounds imultaneously provide antioxidant properties to the resulting polymeric products. Finally, the residual monomer is virtually uncontaminated by these compounds.
The following examples illustrate the preferred embodiments of the invention. In these examples, all parts given are by weight unless othen~ise specified.
Example 1: This example illustrates a typical suspension polymeriza-tion procedure.
REAGENT PARTS
Vinyl Chloride Monomer (VC~I) 100.~0 Initiator-Peroxydicarbonate 0.04 Suspending agent - Methocel type 0.03 NaOH 0.10 H20 (Deaereated Distilled) 200.00 Antioxidant varies Sodium Lauryl Sulfate0.02 A. Filling of Lecture Bottle with 250 g VCM
1. Evacuate air from lecture bottle and weigh.
2. Cool in freezer.
,, ~2639~3 ~lethods for preparing tllese hindered phenols are well known to those skilled in the art. Specific reference is made to U.S.
Patents 3,2851855, 3,944~594 and 4,032,562 for information re-garding the phenols of formulae I and II and their methods of preparation. In general, they are prepared,from the appropriate acids, acid chlorides or lower alkyl esters and alcohols or thio alcohols utilizing well-l;nown esterification or transesterification methods.
As previously noted, these hindered phenols are known for their antioxidant activity in a variety of polymeric substances including polyvinyl chloride. When added to such polymers for purposes of this area of utility, they are generally added to the final polymeric product.
~Tinyl chloride suspension polymerization techniques are likewise well-knonw to those skilled in the art. Such techniques are described in detail in most basic polymer chemistry texts such, for example, as W. Sorenson, "Preparative Methods of Polymer Chemistry", Second Ed., Interscience Publishers, N.~. (196S). In general, the reactor is charged with the appropriate amounts of suspending agent, initiator and emulsifier in the aqueous reaction system. Typical suspending agents include methyl or ethyl cellulose, gelatin, polyvinyl alcohol or other water soluble polymers, while typical initiators include peroxydicarbonate, benzoyl peroxide, lauroyl peroxide, t-butylperbenzoate, acetyl peroxide, cumene hydroperoxide, di-t-butyl peroxide, and the like. The emulsifier is generally added to enhance the porosity of the polymer particles.
' I'.' ,',~
9~3 This charge is generally added to the reactor at ambient temperature.
The vinyL chloride monomer is then introduced, agitation is ini-tiated and the reactor is heated to the polymerization range of from 45 to 60C. The pressure will be in the range of from about 140-150 psi for the 5-7 hour reaction period necessary to achieve about 70% monomer conversion, with the residual monomer being recovered for possible future use. Filtration washing ancl drying complete the polymerization procedure.
In addition to the chemical structure of the instant chain terminators, effective termination is dependent upon the amount of compound added. or purposes of this invention, 25-5000 ppm of hindered phenol, based on the weight of the vinyl chloride monomef9 added at the time of 0 to 95% monomer conversion will provide the desired benefits. Preferred values are 50-1000 ppm of hindered phenol added at 70 to 90% monomer conversion, while particularly preferred concentrations are 50-500 ppm of hindered phenol.
It is to be noted that the latter 70-90% range is the desired range for obtaining commercially acceptable yields of polymer. Howevera the instant hindered phenols will terminate the polymerization reaction at any stage thereof. Accordingly, the 0-95% range reflects the possibility of premature termination where emergency conditions, power outages, and the like, demand such early termination.
The rate of polymerization can be designated in terms of the time to the designated amount of conversion of the polymerization reaction and/or the amount of pressure drop after conversion, the latter being especially indicative of termination capability. In this context, "conversion" is designated as the point during polymeri-zation when vinyl chloride monomer is no longer available as a free monomer and is absorbed into the polymer.
The compounds designated herein are secn to provide immediate termination of vinyl chloride polymerization reactions. This irnmdediate termination alloys for the production of high yields of high quality polyvinyl chloride. These compounds are also seen to provide such rapid termination at concentration levels substantially below that required for currently utilized materials.
The compounds imultaneously provide antioxidant properties to the resulting polymeric products. Finally, the residual monomer is virtually uncontaminated by these compounds.
The following examples illustrate the preferred embodiments of the invention. In these examples, all parts given are by weight unless othen~ise specified.
Example 1: This example illustrates a typical suspension polymeriza-tion procedure.
REAGENT PARTS
Vinyl Chloride Monomer (VC~I) 100.~0 Initiator-Peroxydicarbonate 0.04 Suspending agent - Methocel type 0.03 NaOH 0.10 H20 (Deaereated Distilled) 200.00 Antioxidant varies Sodium Lauryl Sulfate0.02 A. Filling of Lecture Bottle with 250 g VCM
1. Evacuate air from lecture bottle and weigh.
2. Cool in freezer.
3. Place a 3785 cc stainless steel cylinder filled with VC~ in hot water bath (hot tap water).
4. Connect a 3785 cc cylinder to 500 ml lecture bottle with flexible stainless steel hose and connectors.
~-,ji ;3~
~-,ji ;3~
5. Weigh 500 cc cylinder during addition and stop when approximate weigh VCM registers on balance.
6. Weigh 500 cc cylinder with no connections to determine exact amount of VCM inside.
Charging of Reactor 1. Carefully put thistle tube into reactor's entry port.
2. Add sodium lauryl sulfate through thistle tube.
3. Wash tube with 50 parts water.
4. Add suspending agent in 1% solution (aqueous).
5. Washitube with 50 parts water.
6. Add NaOH in 1% solution (aqueous).
Charging of Reactor 1. Carefully put thistle tube into reactor's entry port.
2. Add sodium lauryl sulfate through thistle tube.
3. Wash tube with 50 parts water.
4. Add suspending agent in 1% solution (aqueous).
5. Washitube with 50 parts water.
6. Add NaOH in 1% solution (aqueous).
7. Wash tube with 50 parts water.
8. Add initiator in 7.5% solution (toluene).
9. Wash tube with rest ox water.
10. Turn on pressure and temperature recorders.
C. Charging of Reactor with VCM
1. Heat 500 ml lecture bottle in hot water bath (hot tap water).
2. Connect lecture bottle through quick-connect fittings to reactor.
3. Open valves and VCM will flow in within 60 seconds.
4. Close off valves, start stirring motor at 500 rpm and start pre-heated (62C) circulating water bath through reactor outer jacket.
D. Reaction No 1. Agitate at 500 rpm and heat to reaction temperature oE 57C
within 30 minutes.
2. Typical reaction with peroxydicarbonate initiator achieved 57C
reaction temperature and 140-150 psi reaction pressure approxi-mately 30 minutes after initiating heating. The pressure remains in this range for approximately 5-7 hours or to about 70%
conversion after which the pressure gradually drops.
;~26~g~3 E. Addition of Chain Stopper at 70% Conversion -l. Add desired amount chain stopper to a 40 cc lecture bottl,e.
2. Fill 40 cc lecture bottle with 20-30 g VCM as in Procedure A.
3. At 70% conversion connect lecture bottle to addition part of reactor and heat to 90-100C with electric heat gun (check with pyrometer).
4. Open valves and VCM/chain stopper solution will flow in.
5. Close valves and reweigh lecture bottle to be sure all V~M/chain stopper solution went into reactor.
F. PVC Recovery 1. Vent unreacted VCM slowly into hood, opening and closing valve until no pressure is left in reactor.
2. When all VCM is vented, PVC discharged through bottom port into collection bottle.
3. Filter, then wash with 1000 ml distilled water.
4. Strip wet cake.
The following compounds were utilized in the polymerization procedures noted in the Eollowing examples.
Compound (A) Triethyleneglycol-bis-3-(3-tert.-butyl-4-hydroxy-55-methylphenyl)-propionate (~)Octadecyl-3-(3-tert.-butyl-4-hydroxy-5-methylphenyyl)-propionate (C) 1,6-Hexane diol bis-3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate (D) 1,1,3Tris-(2-methyl-4-hydroxy-5-tert.-butylphenyl)-butaane ~.2~
(E)1,3,5-Tris-(2,6-dimethyl-3-hydroxy-4-tert.-butylbeenzyl)-iso-cyanurate.
Example 2: This example shows the termination effectiveness of a compound of the instant invention in polyvinyl chloride suspension polymerizations The polyrnerization procedure of Ex2mple 1 was utilized herein. In each reaction, the pressure after the terminator had been added and the pressure after a 15 hour reaction sequence were noted. These values were determined by continuous monitoring of the pressure in the reactor. Small pressure drops after the addition of the terminator are indicative of effective termination. The following results were obtained:
Pressure* Pressure**
Concentration Drop after Drop after 70 %
Compound(ppm)15 hours (psi) Conversion (psi) h 250 0 0 * Initial pressure minus the pressure at 15 hours.
** Pressure at 70 % conversion minus the pressure at 15 hours.
l 2~6~
Example 3: The polymerization procedure of Example 1 and the monitoring procedure of Example 2 were again repeated with the com-pounds noted hereinbelow with the exception that the compounds were added at the initiation of the polymerization reaction. Although this approach does not reflect a commercially desirable procedure, it is satisfactory as a screening procedure in order to predict chain termination activity.
Thus, since it can be postulated that the rate of initiation in the polymerization reaction is related to the rate of termination, an additive which slows the rate of polymerization also effects the rate of termination. Accordingly, longer periods to pressure drop are indicative of more effective chain stoppers. Correspondingly, since pressure drop after conversion is indicative of continued reaction and a resultant adverse effect on the po]yvinyl chloride, lower pressure drops are likewise indicative of more effective chain stoppers.
The resulting data are noted in the following table.
Concentration Time to Pressure Drop Compound(ppm) Pressure Drop (min.) after 900min.(psi) In summary, this invention provides a novel use of chain terminating agents in suspension polymerization of vinyl chloride monomer.
Variations may be made in procedures, proportions and materials without departing from the scope of the invention as defined by the following claims.
C. Charging of Reactor with VCM
1. Heat 500 ml lecture bottle in hot water bath (hot tap water).
2. Connect lecture bottle through quick-connect fittings to reactor.
3. Open valves and VCM will flow in within 60 seconds.
4. Close off valves, start stirring motor at 500 rpm and start pre-heated (62C) circulating water bath through reactor outer jacket.
D. Reaction No 1. Agitate at 500 rpm and heat to reaction temperature oE 57C
within 30 minutes.
2. Typical reaction with peroxydicarbonate initiator achieved 57C
reaction temperature and 140-150 psi reaction pressure approxi-mately 30 minutes after initiating heating. The pressure remains in this range for approximately 5-7 hours or to about 70%
conversion after which the pressure gradually drops.
;~26~g~3 E. Addition of Chain Stopper at 70% Conversion -l. Add desired amount chain stopper to a 40 cc lecture bottl,e.
2. Fill 40 cc lecture bottle with 20-30 g VCM as in Procedure A.
3. At 70% conversion connect lecture bottle to addition part of reactor and heat to 90-100C with electric heat gun (check with pyrometer).
4. Open valves and VCM/chain stopper solution will flow in.
5. Close valves and reweigh lecture bottle to be sure all V~M/chain stopper solution went into reactor.
F. PVC Recovery 1. Vent unreacted VCM slowly into hood, opening and closing valve until no pressure is left in reactor.
2. When all VCM is vented, PVC discharged through bottom port into collection bottle.
3. Filter, then wash with 1000 ml distilled water.
4. Strip wet cake.
The following compounds were utilized in the polymerization procedures noted in the Eollowing examples.
Compound (A) Triethyleneglycol-bis-3-(3-tert.-butyl-4-hydroxy-55-methylphenyl)-propionate (~)Octadecyl-3-(3-tert.-butyl-4-hydroxy-5-methylphenyyl)-propionate (C) 1,6-Hexane diol bis-3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate (D) 1,1,3Tris-(2-methyl-4-hydroxy-5-tert.-butylphenyl)-butaane ~.2~
(E)1,3,5-Tris-(2,6-dimethyl-3-hydroxy-4-tert.-butylbeenzyl)-iso-cyanurate.
Example 2: This example shows the termination effectiveness of a compound of the instant invention in polyvinyl chloride suspension polymerizations The polyrnerization procedure of Ex2mple 1 was utilized herein. In each reaction, the pressure after the terminator had been added and the pressure after a 15 hour reaction sequence were noted. These values were determined by continuous monitoring of the pressure in the reactor. Small pressure drops after the addition of the terminator are indicative of effective termination. The following results were obtained:
Pressure* Pressure**
Concentration Drop after Drop after 70 %
Compound(ppm)15 hours (psi) Conversion (psi) h 250 0 0 * Initial pressure minus the pressure at 15 hours.
** Pressure at 70 % conversion minus the pressure at 15 hours.
l 2~6~
Example 3: The polymerization procedure of Example 1 and the monitoring procedure of Example 2 were again repeated with the com-pounds noted hereinbelow with the exception that the compounds were added at the initiation of the polymerization reaction. Although this approach does not reflect a commercially desirable procedure, it is satisfactory as a screening procedure in order to predict chain termination activity.
Thus, since it can be postulated that the rate of initiation in the polymerization reaction is related to the rate of termination, an additive which slows the rate of polymerization also effects the rate of termination. Accordingly, longer periods to pressure drop are indicative of more effective chain stoppers. Correspondingly, since pressure drop after conversion is indicative of continued reaction and a resultant adverse effect on the po]yvinyl chloride, lower pressure drops are likewise indicative of more effective chain stoppers.
The resulting data are noted in the following table.
Concentration Time to Pressure Drop Compound(ppm) Pressure Drop (min.) after 900min.(psi) In summary, this invention provides a novel use of chain terminating agents in suspension polymerization of vinyl chloride monomer.
Variations may be made in procedures, proportions and materials without departing from the scope of the invention as defined by the following claims.
Claims (15)
1. In the process for the suspension polymerization of vinyl chloride monomer which comprises adding the monomer to an aqueous reaction system containing effective amounts of a suspending agent and a polymerization initiator, terminating the polymerization reaction and isolating the polyvinyl chloride, the improvement which comprises terminating the polymerization reaction by the addition to the reaction system at a point within the range of 0 to 95 %
monomer conversion of 25-5000 ppm by weight of the vinyl chloride monomer, of a compound corresponding to the formulae (I) RX-(CaH2a)-Q
wherein R is X is oxygen or sulfur, a is an integer from 6 to 30, x is an integer from 0 to 6, R1 is alkyl from 1 to 8 carbon atoms, Q is hydrogen or -A-(CyH2y)-R2, A is oxygen, sulfur, ? or y is an integer from 0 to 20, B is alkyl of from 1 to 6 carbon atoms or alkanoyl of from 1 to 6 carbon atoms, R2 is hydrogen, hydroxy, alkanoyloxy of from 1 to 6 carbon atoms or , and R3, R4, R5 and R6 independently are alkyl from 1 to 8 carbon atoms;
(II) RX--[(CbH2b)--Y]d-7 wherein R and X are as previously defined, b is an integer from 2 to 6 d is an integer from 3 to 40 Y is oxygen or sulfur, and R7 is hydrogen, alkyl of from 1 to 6 carbon atoms or with R5, R6 and x being as previously defined;
(III) 1,1,3-tris-(2-methyl-4-hydroxy-5-tert.-butylphenyl)-butane or (IV) 1,3,5-tris-(2,6-dimethyl-3-hydroxy-4-tert.-butylbenzyl)-isocyanurate.
monomer conversion of 25-5000 ppm by weight of the vinyl chloride monomer, of a compound corresponding to the formulae (I) RX-(CaH2a)-Q
wherein R is X is oxygen or sulfur, a is an integer from 6 to 30, x is an integer from 0 to 6, R1 is alkyl from 1 to 8 carbon atoms, Q is hydrogen or -A-(CyH2y)-R2, A is oxygen, sulfur, ? or y is an integer from 0 to 20, B is alkyl of from 1 to 6 carbon atoms or alkanoyl of from 1 to 6 carbon atoms, R2 is hydrogen, hydroxy, alkanoyloxy of from 1 to 6 carbon atoms or , and R3, R4, R5 and R6 independently are alkyl from 1 to 8 carbon atoms;
(II) RX--[(CbH2b)--Y]d-7 wherein R and X are as previously defined, b is an integer from 2 to 6 d is an integer from 3 to 40 Y is oxygen or sulfur, and R7 is hydrogen, alkyl of from 1 to 6 carbon atoms or with R5, R6 and x being as previously defined;
(III) 1,1,3-tris-(2-methyl-4-hydroxy-5-tert.-butylphenyl)-butane or (IV) 1,3,5-tris-(2,6-dimethyl-3-hydroxy-4-tert.-butylbenzyl)-isocyanurate.
2. The process of claim l, wherein said compound corresponds to formula I and wherein X is oxygen, x is 0 to 2, R1 is alkyl of from 1 to 4 carbon atoms, A is oxygen, y is 0 to 2, R2 is hydrogen or and R5 and R6 are alkyl of from 1 to 4 carbon atoms.
3. The process of claim 2, wherein R1 and R6 are tert.-butyl positioned in the ortho-position, R5 is methyl and x is 2.
4. The process of claim 3, wherein said compound is octadecyl 3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate.
5. The process of claim 3, wherein said compound is 1,6-hexane diol bis-3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate.
6. The process of claim l, wherein said compound corresponds to formula II and wherein X and Y are oxygen, x is 0 to 2, R1 is alkyl from 1 to 4 carbon atoms, b is 2, d is 3 to 20, R7 is and R5 and R6 are alkyl of from 1 to 4 carbon atoms.
7. The process of claims 6, wherein R1 and R6 are tert.-butyl positioned in the ortho-position and R5 is methyl.
8. The process of claim 7, wherein said compound is triethylene glycol bis-3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate.
9. The process of claim 1, wherein said compound corresponds to 1,1,3-tris-(2-methyl-4-hydroxy-5-tert.butyl-phenyl)-butane.
10. The process of claim 1, wherein said compound corresponds to 1,3,5-tris-(2,6-dimethyl-3-hydroxy-4-tert.-butylbenzyl)-isocyanurate.
11. The process of claim 1, wherein said addition occurs within the range of 70 - 90 % monomer conversion.
12. The process of claim 11, wherein said addition occurs at about 70 % monomer conversion.
13. The process of claim 12, wherein 50 - 1000 ppm of said compound are added to the reaction system.
14. The process of claim 13, wherein 50 - 500 ppm of said compound are added to the reaction system.
15. The process of claim 1, wherein 100 - 250 ppm of triethylene glycol bis-3-(3-tert.-butyl-4-hydroxy-5-methylphenyl)-propionate are added to the reaction system at about 70 % monomer conversion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US28038981A | 1981-07-06 | 1981-07-06 | |
| US280,389 | 1981-07-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1226398A true CA1226398A (en) | 1987-09-01 |
Family
ID=23072875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000406483A Expired CA1226398A (en) | 1981-07-06 | 1982-07-02 | Chain terminators for polyvinyl chloride polymerization |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0069702B1 (en) |
| JP (1) | JPS5817106A (en) |
| CA (1) | CA1226398A (en) |
| DE (1) | DE3264027D1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1501878A1 (en) | 2002-05-01 | 2005-02-02 | Ciba SC Holding AG | Process for chain stopping of pvc polymerization |
| JP2012520879A (en) * | 2009-03-20 | 2012-09-10 | スマートセルズ・インコーポレイテツド | End-functionalized conjugates and uses thereof |
| CN109265587A (en) * | 2018-09-11 | 2019-01-25 | 蓝凤祥 | A kind of anti-freeze type high fever ageing whiteness polyvinyl chloride terminates agent emulsion and preparation method thereof |
| CN111393548B (en) * | 2020-04-13 | 2022-05-13 | 内蒙古鄂尔多斯电力冶金集团股份有限公司 | Preparation method of polyvinyl chloride resin with high thermal stability |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3285855A (en) * | 1965-03-11 | 1966-11-15 | Geigy Chem Corp | Stabilization of organic material with esters containing an alkylhydroxy-phenyl group |
| US4229598A (en) * | 1978-12-14 | 1980-10-21 | Conoco, Inc. | Chemicals for treatment of PVC |
| US4324874A (en) * | 1980-10-08 | 1982-04-13 | Tenneco Chemicals, Inc. | Production of vinyl halide polymers with dialkyl, hydroxy phenyl alkanoic ester of polyhydric alcohols |
-
1982
- 1982-06-30 DE DE8282810280T patent/DE3264027D1/en not_active Expired
- 1982-06-30 EP EP19820810280 patent/EP0069702B1/en not_active Expired
- 1982-07-02 CA CA000406483A patent/CA1226398A/en not_active Expired
- 1982-07-06 JP JP11760582A patent/JPS5817106A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| EP0069702A3 (en) | 1983-04-06 |
| EP0069702B1 (en) | 1985-06-05 |
| EP0069702A2 (en) | 1983-01-12 |
| JPH0322885B2 (en) | 1991-03-27 |
| DE3264027D1 (en) | 1985-07-11 |
| JPS5817106A (en) | 1983-02-01 |
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