CA1093747A - Suspension poymerization - Google Patents
Suspension poymerizationInfo
- Publication number
- CA1093747A CA1093747A CA317,317A CA317317A CA1093747A CA 1093747 A CA1093747 A CA 1093747A CA 317317 A CA317317 A CA 317317A CA 1093747 A CA1093747 A CA 1093747A
- Authority
- CA
- Canada
- Prior art keywords
- styrene
- suspending agent
- suspending
- suspension
- inorganic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- 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
- C08F112/00—Homopolymers 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 an aromatic carbocyclic ring
- C08F112/02—Monomers containing only one unsaturated aliphatic radical
- C08F112/04—Monomers containing only one unsaturated aliphatic radical containing one ring
- C08F112/06—Hydrocarbons
- C08F112/08—Styrene
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polymerisation Methods In General (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Large particles are obtained in the suspension polymerization of styrene by employing an inorganic parti-culate suspending agent in the initial phase of polymeri-zation and after about 20 to 40 weight percent conversion of monomer to polymer, a water-dispersible organic sus-pending agent is added.
25,760-F
Large particles are obtained in the suspension polymerization of styrene by employing an inorganic parti-culate suspending agent in the initial phase of polymeri-zation and after about 20 to 40 weight percent conversion of monomer to polymer, a water-dispersible organic sus-pending agent is added.
25,760-F
Description
3~7 SUSPENSIOW POLYMERIZATIOW
One partioularly convenient means of obtaining styrene polymers i.s by suspension polymerization. A solu-tion of styrene and a polymPrization promoter such as a peroxide is~dispersed~in an aqueous suspending medium by means of agitation to form droplets~ The droplets sub-sequently p~lymerize to form beads or pearls o~ polysi-yr~ne in which a blowing or foaming agent may be incorporate~.
Depending upon the end~use of the particular polystyxene, it~may be~desi~able~that the pearls or beads be large mall or~have~a narrow~;particle size distribution. For 10 ~ he preparation~of expan~able polystyrene particles which are to be molde~d~;into relatively large blocks or articlest it is desi~able~that lar~e polymer particles ha~ing pre-feral~ly, a narrow parti~cle size distribution be employed.
A typical large particle size polystyrene particulate mass would pass a 2~ mesh U.S. sieve si2e screen and be sub-- ~ stantia~ly retained~on a 40 mesh U.S~ sieve siæe screen.
In~oon~ention~ s~spension polymerization procedures, usually : a much broader parti~le size distribution is obtained. A
variety o~ polymerization systems are ]cnown whe ein the 0 ~ particle~size~istribution is varied by a va~ie~y of r.eans~
su`ch~as lnc~e2sing or~decreasin~ the quantity of suspendin~
agenti em~loyin~two~dlfferent suspending agents at the ame time~or~employing~a~coL10idal~suspend.ng agent to~ether 25~,7~6~-F
.
:
:: :
~LVS~3r~ 7 with an anionic detergent. British Patent 1,344,060 discloses the prep-aration of nonspherical particles in a suspension pol~nerization system by a two-stage addition of the suspending agent.
Suspension polymerization employing particulate inorganic suspending agents and water-soluble or dispersible organic suspending agents is well kno~. U.S. Patent 2,440,808 discloses the use of magnesium silicate as a suspending agent. U.S. Patent 2,687,408 discloses phosphates as sus-pending agents. U.S. Patent 2,715,118 also employs phosphates. Organic materials are disclosed in U.S. Patent ~,932,629. U.S. Patent 2~934~530 discloses organic and inorganic suspending agent in a suspension poly-meriza~ion. U.S. Patent 3,192,169 discloses the preparation of expandable polymeric styrene particles with inorganic or organic suspending agents.
Mixed organic and inorganic suspending agents are disclosed in U.S. Patents 3,068,1~2; 3,328,374; and 3,786,115.
It would be desirable if there were~available an improved suspension polymerization method for the preparation of polystyrene.
It would also be desirable if there were available an improved suspension polymerization process for polystyrene w1l1ch produced primarily larger beads.
20 ~ ~ ~ These benefits and other advantages in accordance witli the presen~ -invention are achieved~1n a methoi for the preparation of polystyrene particles wherein styrene monomer containing a styrene sGlubie free radical ~initiator~is dispersed in an~aqueous suspending medium containing a sus pen~ing agent to form a styrene suspension in water, heating the suspension to a temperature suff1clent ; ;;
One partioularly convenient means of obtaining styrene polymers i.s by suspension polymerization. A solu-tion of styrene and a polymPrization promoter such as a peroxide is~dispersed~in an aqueous suspending medium by means of agitation to form droplets~ The droplets sub-sequently p~lymerize to form beads or pearls o~ polysi-yr~ne in which a blowing or foaming agent may be incorporate~.
Depending upon the end~use of the particular polystyxene, it~may be~desi~able~that the pearls or beads be large mall or~have~a narrow~;particle size distribution. For 10 ~ he preparation~of expan~able polystyrene particles which are to be molde~d~;into relatively large blocks or articlest it is desi~able~that lar~e polymer particles ha~ing pre-feral~ly, a narrow parti~cle size distribution be employed.
A typical large particle size polystyrene particulate mass would pass a 2~ mesh U.S. sieve si2e screen and be sub-- ~ stantia~ly retained~on a 40 mesh U.S~ sieve siæe screen.
In~oon~ention~ s~spension polymerization procedures, usually : a much broader parti~le size distribution is obtained. A
variety o~ polymerization systems are ]cnown whe ein the 0 ~ particle~size~istribution is varied by a va~ie~y of r.eans~
su`ch~as lnc~e2sing or~decreasin~ the quantity of suspendin~
agenti em~loyin~two~dlfferent suspending agents at the ame time~or~employing~a~coL10idal~suspend.ng agent to~ether 25~,7~6~-F
.
:
:: :
~LVS~3r~ 7 with an anionic detergent. British Patent 1,344,060 discloses the prep-aration of nonspherical particles in a suspension pol~nerization system by a two-stage addition of the suspending agent.
Suspension polymerization employing particulate inorganic suspending agents and water-soluble or dispersible organic suspending agents is well kno~. U.S. Patent 2,440,808 discloses the use of magnesium silicate as a suspending agent. U.S. Patent 2,687,408 discloses phosphates as sus-pending agents. U.S. Patent 2,715,118 also employs phosphates. Organic materials are disclosed in U.S. Patent ~,932,629. U.S. Patent 2~934~530 discloses organic and inorganic suspending agent in a suspension poly-meriza~ion. U.S. Patent 3,192,169 discloses the preparation of expandable polymeric styrene particles with inorganic or organic suspending agents.
Mixed organic and inorganic suspending agents are disclosed in U.S. Patents 3,068,1~2; 3,328,374; and 3,786,115.
It would be desirable if there were~available an improved suspension polymerization method for the preparation of polystyrene.
It would also be desirable if there were available an improved suspension polymerization process for polystyrene w1l1ch produced primarily larger beads.
20 ~ ~ ~ These benefits and other advantages in accordance witli the presen~ -invention are achieved~1n a methoi for the preparation of polystyrene particles wherein styrene monomer containing a styrene sGlubie free radical ~initiator~is dispersed in an~aqueous suspending medium containing a sus pen~ing agent to form a styrene suspension in water, heating the suspension to a temperature suff1clent ; ;;
2 -.
.
. . .
, .'.'.
' ~ '' . ., -,' . ' - : .
~.~3~'7~
to initiate polymerization of the ~tyrene monomer to form styrene polymer and subsequently recovering generally spherical polystyrene par-~icles from the suspenAing m~dia, the improvement which comprises providing as a suspending S a~nt within the suspendinf~f medium an inorganic parti culate suspending agent in a quantity su~ficient to ini.tially stabilize the di.spersion of styrenP in water until from about 20 weight percent to about 40 weight percent of the styrene monomer is converted to polymer and subsequently adding an organic suspending agent to stabiliæe the resulting suspension.
Polymerization ir. accordance with the present invention is generally accomplished employing temperatures between about 60C and 140C, beneficially, frcm about 70C
~ 15 to 120C. Usually depending upon the properties desired : and the resultant polymer, the temperature of the polymeri-zation reaction is raised either continuously or stepwise ~rom a lower value to a higher value during the course o~
the reaction. Such temperature programming is familiar to those skilled in the art of styrene polymerizationu Gen-exally, in the suspension polymerization of polystyrene, : the weicJht ratio of styrene to water is maintained within the range of 00501 to 1.5:1 and beneficlally from 1:1 to 1~2:1. Beneficial].y, in the practice or the presenk inven tion, the appropriate amount of water containing the inorgani.c suspendillg agent is added to the polymerization vessel or alternatively the water added and the suspending agent dispersed therein. ~he polymerization reactor is then freed of ..sub5 ~ antial amounts of oxygen by the appli-cation of vacuum or a nit.rogen purge or both. The mono-mer containing the free radical initiator is added to the xeactor with agitaticn suf~icien~ ~o disperse ~he monomer as a plurality of droplts. The agitation.is maintained throug;lout ~he polymerization. The temperature of the reaction mi~ture is raised to polymerization tempera~ure ; - ~ 25,760-F
.
. ~ -, . . -7~7 and when 20 to 40 weight percent of the styrene added i5 converted to polymer, the water dispersible organic sus-pending agent is added as an aqueous dispersion. Due to the individual nature of suspension polymerization reactors, optimum agitation speed must be determined for each vessel.
Generally, the optimum a~itation speed will be about 20 percent less than the speed of agitation found satisEac-tory for conventional small particle size polymerization axried out in the same vesselO If the vessel is equipped with a view port, that amount of agitation just sufficient to maintain dispersion without vi~ible pooling of the monomer on the upper surface of the reaction muxture is generally found to be satisactory. After at least 20 percent conversion of monomer has ta~en place, and pre-ferably at a conversion in the range of 30 to 40 pexcentwherein suf~iciently large size beads are formed, the organic susp~nding agent is added to provide a dispersion ~hat is stable for the remainder of the polymerizationJ
Enough organic suspending agent should be added in the second stage polyrnerization to achieve conventional suspension polymerization stability. Generally, the total amount of organic suspending agent is in the range of 0~0~ to 0~4 percent by weight of monomer plus polymer, preferably 0.1 to 0.3 weight percent. The inorganic ~5 particulate suspending agents employed should be insoluble or, a-t mostr of very limited solubility in the suspension medium. Thus, any phosphate of calcium, bariuml strontium, magnesium, alu~num, zinc or cadmium generally considered for mos~ purposes ~o be water insoluble can be employed.
Other typically suitable compounds include the aluminum silicates and fluoro-silicates, magnesium carbonate, mag~
nesium oxide/ zinc oxide, talc (hydrous ma~nesium silicate), ~y~barium e~ cer baxium sulfate, and calcium carbonateO
Such agents can be used singly, or in combination, e.g.
; 35 tricalcium phosphate with a lesser propor~ion of calcium 25l760-F
:
: ~ - . ' . . : .
. ' ' ~ ' , , :
:
~5-carbonate. Such inorganic particulate suspending agents are well known to those skilled in the suspension poly-merization art.
T~e organic suspendinq agents utilized ~n the practice of the present invention include salts of poly-acrylic acid, gelatin, pectin, various starches, alginates, car~oxymethyl methylcellulose and other cellulose deriva-tives, polyvinylpyrrolidane, polyvinyl alcollol, an~ the like known suspending agents. The optimum concentration for any particular combination of suspending agents must be determined by experimentation.
Any convenient monomer soluble initiator system can be used. Suitable initia~ors include lauroyl peroxide, octanoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichloro-benzoyl peroxide, benzoyl peroxide, di-isopropyl peroxy~
dicarbonate, t-butyl perbenzoate, dicumyl peroxide, di-t--butyl peroxide, and di-t~butyl perphthalate a~obisisobutyro-nitrile. Usually for ~styrene polymerization a mixture of initiators ls employed~
The polymerization conditions are preferably selected so that the polymeriæation is considered com-pleted within 16 hours, prefe~ably within 1~ hours.
Temperature range of the polymerization of styrene is suitably 60C to 140~C, most preferably 70C to 120C.
Othçr conventional ingredients of suspension polymerization systems such as volatile fluid foaming ayen~s, molecular weiyht control agents, lubricants and the like ~ay be present in the reactor.
,, .
The invention is further illustxated but not limited by tlle following e~amples wherein the average bead 2~,760-F
.
, - ' , size was determined in accordance with the American Society for Testing Material Procedure D-1921-63 Method ~.
A plurality of suspension polymerizations were conducted employing various combinations of suspending ^- 5 agent. In each case/ ~he charge to a stirred reactor WAS 759 grams of a solution containing 0O087 weight per~
cent azobisisobutyronitrile, 0.15 weight percent benzoyl peroxide and 0.068 weight percent ~ertiarybutyl perben-zoate, 5 weight percent polystyrene, 0.1 weight percent Minex 7 t a sodium-aluminum silicate, the remainder bein~
styrene. The solution was charged to a nitrogen-purged ~llter glass polymerization vessel containing 520 g:cams of water, 0.62 grams of sodium dichromate together with the suspending agent employed. The reactor had a loop agitator which was rotated at 200 revolutions per minute~
Polymeriza-tion was conducted at 85C. Carboxymethyl methylcellulose (CMMC) was employed as a water-soluble organic dispersion agent. Three hours after the reaction ixture reached 85C the carboxymethyl methylcellulose ; 20 was added. A solution of 1.24 grams of the cellulose derivative in 100 grams of water was employed. A total polymerization time of ten hours was employed. At the end of this period of time, the reactor and contents were cooled, and the resultant polystyrene beads ~iltered, washed and driedO The particle size was analyzed by sieve ; analysis (U.S. sieve size)~ trhe results of the experi-ments are set for~h in the follQwing Table. Runs 7 and 8 are for comparative purposes~
, 25,760-F
' : :
:, ' . ' ' :' -- . : - :
' ' - ' :' ' ~
N
~
U:
a) , a) ~
6) N lU
~-r1 rl ~ ~ ~r `~
~ 1 ~1 Z ~ ~7 ~1 ~;
m P
..........,,............................ o o .,~
o ~:
O h Ql 5 ~ u~
O
V C) ~ ~ ~ U O
~ ~ O ~ ~
O ~ ~ O
0-rl ~ ~ ~ ~ 4~ ~1 0 ~1 ~H ~J
~ ~, o o o o o o ~ ~:) o o HId-.1 ~1 ~ O
o~O oP o~> o'~O ~ o~ O o~O
~; ~ O O O o O O ~ ~ o l~
rt I¢ O O O O O O d O o o ~;
~ ~ I r~ ; r~ ~
E~
O .,1 ,1 X
~ ~: x tR O ~ O O ~ a ~ ~ ~ ~ O ~ ~ O ~ ~ ~ ~ '~
u~ ~ O O c~ o o uCJ ~ Q
S:: V O b U ~ ~ ~ ~ O O
,1 o~o 0~O ,~
~ oP 0\0 If ~ 0 o\O If) 0~ G~O 0~0 0~ ~ Q.l rl ~ r-l O t'`J r l O O O ~ I-t ~1 t;l ~ O O
H O O O O O C~ 1 r-l O O
~ :~ $
:~: ~ Z
'- ~
:
~, ~;
25, 760- F
~ ` ~
: ~ :
~: ~
:
.~
. .
.
.
. ., ` :
7~7 In a manne~ simi].ar to the foregoing illustrations, use of other inorganic and organic suspending agents pro-vides desirable increased particle size .in styrene suspen sion polymerizations.
As is apparent from the foregoing spe~ificationr the present invention is susceptible of being embodied wit~ various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that al]. of the fore-going is intended to be merely illustrative and is not to be construed or interpreted as being restrictiva or othenw.ise limiting of the present invention, excepting as it is set forth and defined in the hereto-appended cla.ims~
2~,760--Y
'
.
. . .
, .'.'.
' ~ '' . ., -,' . ' - : .
~.~3~'7~
to initiate polymerization of the ~tyrene monomer to form styrene polymer and subsequently recovering generally spherical polystyrene par-~icles from the suspenAing m~dia, the improvement which comprises providing as a suspending S a~nt within the suspendinf~f medium an inorganic parti culate suspending agent in a quantity su~ficient to ini.tially stabilize the di.spersion of styrenP in water until from about 20 weight percent to about 40 weight percent of the styrene monomer is converted to polymer and subsequently adding an organic suspending agent to stabiliæe the resulting suspension.
Polymerization ir. accordance with the present invention is generally accomplished employing temperatures between about 60C and 140C, beneficially, frcm about 70C
~ 15 to 120C. Usually depending upon the properties desired : and the resultant polymer, the temperature of the polymeri-zation reaction is raised either continuously or stepwise ~rom a lower value to a higher value during the course o~
the reaction. Such temperature programming is familiar to those skilled in the art of styrene polymerizationu Gen-exally, in the suspension polymerization of polystyrene, : the weicJht ratio of styrene to water is maintained within the range of 00501 to 1.5:1 and beneficlally from 1:1 to 1~2:1. Beneficial].y, in the practice or the presenk inven tion, the appropriate amount of water containing the inorgani.c suspendillg agent is added to the polymerization vessel or alternatively the water added and the suspending agent dispersed therein. ~he polymerization reactor is then freed of ..sub5 ~ antial amounts of oxygen by the appli-cation of vacuum or a nit.rogen purge or both. The mono-mer containing the free radical initiator is added to the xeactor with agitaticn suf~icien~ ~o disperse ~he monomer as a plurality of droplts. The agitation.is maintained throug;lout ~he polymerization. The temperature of the reaction mi~ture is raised to polymerization tempera~ure ; - ~ 25,760-F
.
. ~ -, . . -7~7 and when 20 to 40 weight percent of the styrene added i5 converted to polymer, the water dispersible organic sus-pending agent is added as an aqueous dispersion. Due to the individual nature of suspension polymerization reactors, optimum agitation speed must be determined for each vessel.
Generally, the optimum a~itation speed will be about 20 percent less than the speed of agitation found satisEac-tory for conventional small particle size polymerization axried out in the same vesselO If the vessel is equipped with a view port, that amount of agitation just sufficient to maintain dispersion without vi~ible pooling of the monomer on the upper surface of the reaction muxture is generally found to be satisactory. After at least 20 percent conversion of monomer has ta~en place, and pre-ferably at a conversion in the range of 30 to 40 pexcentwherein suf~iciently large size beads are formed, the organic susp~nding agent is added to provide a dispersion ~hat is stable for the remainder of the polymerizationJ
Enough organic suspending agent should be added in the second stage polyrnerization to achieve conventional suspension polymerization stability. Generally, the total amount of organic suspending agent is in the range of 0~0~ to 0~4 percent by weight of monomer plus polymer, preferably 0.1 to 0.3 weight percent. The inorganic ~5 particulate suspending agents employed should be insoluble or, a-t mostr of very limited solubility in the suspension medium. Thus, any phosphate of calcium, bariuml strontium, magnesium, alu~num, zinc or cadmium generally considered for mos~ purposes ~o be water insoluble can be employed.
Other typically suitable compounds include the aluminum silicates and fluoro-silicates, magnesium carbonate, mag~
nesium oxide/ zinc oxide, talc (hydrous ma~nesium silicate), ~y~barium e~ cer baxium sulfate, and calcium carbonateO
Such agents can be used singly, or in combination, e.g.
; 35 tricalcium phosphate with a lesser propor~ion of calcium 25l760-F
:
: ~ - . ' . . : .
. ' ' ~ ' , , :
:
~5-carbonate. Such inorganic particulate suspending agents are well known to those skilled in the suspension poly-merization art.
T~e organic suspendinq agents utilized ~n the practice of the present invention include salts of poly-acrylic acid, gelatin, pectin, various starches, alginates, car~oxymethyl methylcellulose and other cellulose deriva-tives, polyvinylpyrrolidane, polyvinyl alcollol, an~ the like known suspending agents. The optimum concentration for any particular combination of suspending agents must be determined by experimentation.
Any convenient monomer soluble initiator system can be used. Suitable initia~ors include lauroyl peroxide, octanoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichloro-benzoyl peroxide, benzoyl peroxide, di-isopropyl peroxy~
dicarbonate, t-butyl perbenzoate, dicumyl peroxide, di-t--butyl peroxide, and di-t~butyl perphthalate a~obisisobutyro-nitrile. Usually for ~styrene polymerization a mixture of initiators ls employed~
The polymerization conditions are preferably selected so that the polymeriæation is considered com-pleted within 16 hours, prefe~ably within 1~ hours.
Temperature range of the polymerization of styrene is suitably 60C to 140~C, most preferably 70C to 120C.
Othçr conventional ingredients of suspension polymerization systems such as volatile fluid foaming ayen~s, molecular weiyht control agents, lubricants and the like ~ay be present in the reactor.
,, .
The invention is further illustxated but not limited by tlle following e~amples wherein the average bead 2~,760-F
.
, - ' , size was determined in accordance with the American Society for Testing Material Procedure D-1921-63 Method ~.
A plurality of suspension polymerizations were conducted employing various combinations of suspending ^- 5 agent. In each case/ ~he charge to a stirred reactor WAS 759 grams of a solution containing 0O087 weight per~
cent azobisisobutyronitrile, 0.15 weight percent benzoyl peroxide and 0.068 weight percent ~ertiarybutyl perben-zoate, 5 weight percent polystyrene, 0.1 weight percent Minex 7 t a sodium-aluminum silicate, the remainder bein~
styrene. The solution was charged to a nitrogen-purged ~llter glass polymerization vessel containing 520 g:cams of water, 0.62 grams of sodium dichromate together with the suspending agent employed. The reactor had a loop agitator which was rotated at 200 revolutions per minute~
Polymeriza-tion was conducted at 85C. Carboxymethyl methylcellulose (CMMC) was employed as a water-soluble organic dispersion agent. Three hours after the reaction ixture reached 85C the carboxymethyl methylcellulose ; 20 was added. A solution of 1.24 grams of the cellulose derivative in 100 grams of water was employed. A total polymerization time of ten hours was employed. At the end of this period of time, the reactor and contents were cooled, and the resultant polystyrene beads ~iltered, washed and driedO The particle size was analyzed by sieve ; analysis (U.S. sieve size)~ trhe results of the experi-ments are set for~h in the follQwing Table. Runs 7 and 8 are for comparative purposes~
, 25,760-F
' : :
:, ' . ' ' :' -- . : - :
' ' - ' :' ' ~
N
~
U:
a) , a) ~
6) N lU
~-r1 rl ~ ~ ~r `~
~ 1 ~1 Z ~ ~7 ~1 ~;
m P
..........,,............................ o o .,~
o ~:
O h Ql 5 ~ u~
O
V C) ~ ~ ~ U O
~ ~ O ~ ~
O ~ ~ O
0-rl ~ ~ ~ ~ 4~ ~1 0 ~1 ~H ~J
~ ~, o o o o o o ~ ~:) o o HId-.1 ~1 ~ O
o~O oP o~> o'~O ~ o~ O o~O
~; ~ O O O o O O ~ ~ o l~
rt I¢ O O O O O O d O o o ~;
~ ~ I r~ ; r~ ~
E~
O .,1 ,1 X
~ ~: x tR O ~ O O ~ a ~ ~ ~ ~ O ~ ~ O ~ ~ ~ ~ '~
u~ ~ O O c~ o o uCJ ~ Q
S:: V O b U ~ ~ ~ ~ O O
,1 o~o 0~O ,~
~ oP 0\0 If ~ 0 o\O If) 0~ G~O 0~0 0~ ~ Q.l rl ~ r-l O t'`J r l O O O ~ I-t ~1 t;l ~ O O
H O O O O O C~ 1 r-l O O
~ :~ $
:~: ~ Z
'- ~
:
~, ~;
25, 760- F
~ ` ~
: ~ :
~: ~
:
.~
. .
.
.
. ., ` :
7~7 In a manne~ simi].ar to the foregoing illustrations, use of other inorganic and organic suspending agents pro-vides desirable increased particle size .in styrene suspen sion polymerizations.
As is apparent from the foregoing spe~ificationr the present invention is susceptible of being embodied wit~ various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that al]. of the fore-going is intended to be merely illustrative and is not to be construed or interpreted as being restrictiva or othenw.ise limiting of the present invention, excepting as it is set forth and defined in the hereto-appended cla.ims~
2~,760--Y
'
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a method for the preparation of polystyrene particles wherein styrene monomer containing a styrene soluble free radical initiator is dispersed in an aqueous suspending medium containing a suspending agent to form a styrene suspension in water, heating the suspension to a temperature sufficient to initiate polymerization of the styrene monomer to form styrene polymer and subsequently recovering generally spherical polystyrene particles from the suspending media, the improvement which comprises pro-viding as a suspending agent within the suspending medium an inorganic particulate suspending agent in a quantity sufficient to initially stabilize the dispersion of styrene in water until from about 20 weight percent to about 40 weight percent of the styrene monomer is converted to polymer and subsequently adding an organic suspending agent to stabilize the resulting suspension.
2. The method of Claim 1 wherein the inorganic suspending agent is magnesium carbonate.
3. The method of Claim 1 wherein the inorganic suspending agent is magnesium pyrophosphate.
4. The method of Claim 1 wherein. the organic suspending agent is carboxymethyl methylcellulose.
25,760-F
25,760-F
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA317,317A CA1093747A (en) | 1978-12-04 | 1978-12-04 | Suspension poymerization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA317,317A CA1093747A (en) | 1978-12-04 | 1978-12-04 | Suspension poymerization |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1093747A true CA1093747A (en) | 1981-01-13 |
Family
ID=4113065
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA317,317A Expired CA1093747A (en) | 1978-12-04 | 1978-12-04 | Suspension poymerization |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1093747A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6239224B1 (en) | 1997-10-10 | 2001-05-29 | Polymer Systems As | Method of production of particulate polymers |
-
1978
- 1978-12-04 CA CA317,317A patent/CA1093747A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6239224B1 (en) | 1997-10-10 | 2001-05-29 | Polymer Systems As | Method of production of particulate polymers |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4352916A (en) | Use of hydrophobically modified water soluble polymers in suspension polymerization | |
| US2701245A (en) | Bead polymerization of methyl methacrylate | |
| US2992544A (en) | Insoluble resinous copolymers of (chloromethyl) styrene and polyvinyl aromatic hydrocarbons and nitrogen-containing derivatives of the copolymers | |
| US3322695A (en) | Preparation of porous structures | |
| US3726846A (en) | Polymerisation of styrene and similar monomers using a continuously increasing temperature cycle | |
| EP0266074A1 (en) | Process for polymerising one or more 1-olefins in the gas phase in the presence of pulverulent inorganic material | |
| US3068185A (en) | Method for preparing aqueous dispersions of clay coated with polymers of ethylenically unsaturated monomers and aqueous film forming compositions produced thereby | |
| CA1093747A (en) | Suspension poymerization | |
| US4385156A (en) | Process for producing coated styrenic polymer beads for heat resistant foams | |
| US3222343A (en) | Process for producing flat particles of polymers of vinyl aromatic monomers | |
| JPS6121736A (en) | Separation inert bead for regenerating mixed bed ion exchange resin | |
| US4042541A (en) | Expandable polystyrene particles | |
| US3243419A (en) | In situ generation of suspending agent in the suspension polymerization of styrene | |
| EP0396046B1 (en) | Method for producing expandable thermoplastic polymer particles | |
| US3563936A (en) | Plastisol composition | |
| CA1237244A (en) | Continuous process for the production of vinyl chloride polymers in aqueous suspension | |
| US3535301A (en) | Process for obtaining powders of polytetrafluoroethylene | |
| US3063954A (en) | Process for producing flame-retardant expandable polystyrene particles | |
| US3879313A (en) | Stabilization of vinyl resin foam systems | |
| NO842503L (en) | PVC PRODUCT AND PROCEDURE FOR ITS MANUFACTURING | |
| US4436861A (en) | Polyvinyl chloride containing alkyl acrylate and alkyl methacrylate sequentially polymerized thereon | |
| US3597370A (en) | Hollow bodies of copolymers of vinyl chloride and ethylene | |
| US3480602A (en) | Polymerisation process | |
| US5225458A (en) | Powder of (co)polymer of one or more 1-olefins blended with pulverulent inorganic material | |
| US3607980A (en) | Method of polymerizing vinyl chloride with ethylene-vinyl acetate copolymers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |