CA1132123A - Initiator compositions for vinyl chloride polymerization - Google Patents

Abstract

ABSTRACT
In vinyl chloride polymerization, the rate of polymeriz-ation is significantly increased by using an organic azo or peroxide free-radical initiator composition containing about 4.0 to 30% by weight based on the initiator of an alkyl or aralkyl alcohol of 8 to 20 carbons.

Description

' I j ; ,-'-- - 1 Initiator Compositions for Vinyl Chloride Polymerization (IR 2443A) Thls invention relates to a novcl initiator composition and a method of usin~ thls co;npositior. $or an L~ ro~ed vinyl chloride polymerization .
This preparation of polyvinyl chloride (hereinafter referred to as PVC) resin by cither suspcnsion (or bulk) polymeri~at'on either alonc or in combination tvith othcr in~rcdients is tvell-known.
" ' ~ ~

~3Z123 U.S. Patent 3,324,097 describes a process for reducing wet polymer buildup in the reaction vessel during vinyl chloride dispersion polymerization. The monomer and an organic peroxydicarbonate initiator is dispersed ln water using a ~--~ ~~
surfactant. The resulting dispersion is homogenized and polymer-ized at 40 to 65 C in the presence of at least 0.05% (based on the weight of monomer) of certain long chain materials including aliphatic or araliphatic alcohols containing at least 8 carbons; U.S. Patent .
4,058,495 describes a process for preparing high bulk density/
porosity PVC resin by suspension polymerization. The polymerization is conducted in the presence of hydroxy-ethyl cellulose (suspending agent) and an internal lubrLcant compound that is soluble in vinyl chloride monomer, insoluble in . . ;
water, and has a minimum chain length of about 12 carbons.
Examples of these compounds are alLphatic alcohols, acids, esters and waxes, with a water insoluble initiator such as ~3 lauroyl peroxide. The aliphatic alcohols are used in a con- ~`
centration range of 0.1 to 5.0 parts per hundred parts of monomer.
Since long chain alcohols are used in this process, dusting of the polymer ~vould occur. U.S. Patent 4,076,920 describes a process for reducing polymer buildup in the reactor during vinyl chloride dispersion polymerization and an aqueous alkaline medium.
According to this process, the emulsifler system comprises the . ~, . , ~.

~) ~13'~
_; ~ 3 ~-- = ammonium salt of a fatty acid of 8 to 20 carbons and at leasT: ne long chain alcohol of 14 to 24 carbons wherein the ratio of alcohol to emulsifier is equai or less than 1,0 and the reaction ingredients .
are preEerably homogenized prior to polymerization, British Patent No. 1,501,594 describes a process forvinyl chloride suspension polymerization wherein the initiator is added as a solution in a plasticizer. According to this process, this shortens the reaction or polymerization time. The plasticizers are dialkyl esters of 4 to 14 carbons derived from dicarboxylic acids and used in a range of 0.1 to 10% by weight based on the weight of the monomer, None of these references teach the present invention because the concentration of the long chain alcohol in the present invention is less than 0.1% by weight if based on the weight of the monomer. This lower concentration of the alcohol is lcss likely to cause dusting problems in the polymerization. The present invention also leads to the slgnificant reduction in cycle time without sacrificing other desirable features of the polymeriz-ation system, such as, clean reactors withollt excessive scale build-up as in prior art processes; and resin has a narrower particle size distribution and a lower percentage of oversize particles resulting in reduced time in resin processing operation such as extrusion, calendering, injection, etc. The increase in the rate of polvmerization is obtained early in the reaction and ,,.,i , 3Z~Z~3 ~

:, ~ = thus does not lead o an excessive heat kick towards the end of i l ~ the reaction. This leads to a more uniform rate of polymerization whereby the avallable reactor cooling capaaity is more efficiently utilized, improving the economics of the process. The present invention is also directed to suspension (or bulk) polymerization which is distinctly different from dispersion (also called an emulsion) polymerization. In dispersion polymerization, emulsify-- ing agents, commonly anionic emulsifying agents' are used with ~ -the final polymer particles being in the form of latex and particulate lo in size. In suspension polymerization, on the other hand, suspend-lng agents such as polyvinyl alcohol and various cellulose - derivatives are used with the resulting polymer being in the form of beads that can be easily recovered by filtration. Moreover,because of the difference in polymerization characteristics, the polymer .. ..
from dispersion polymerization has a higher molecular weight than from suspension polymerization.

Statément of the Invention The present invention is dir~cted to a novel initiator composition for suspension or bulk polymerization of vinyl -hloride consisting essentially of O.OOS to 0 .25 parts by weight per hundred parts by weight of monomer of an initiator selectèd from the class consisting of a symmetrical or unsymmetrical free radical prcducing azo, peroxydicarbonate, a-branched peroxy ~ster, diacyl ~3'~
, .

peroxide and mixtures thereof, and 4.0 to 30% by -Yleight basea on the initiator of one or more alkyl or aralkyl alcohols of ~ to 20 carbons.
The present invention is also directed to the using of the above mentioned novel initiator composition in a method of pro-ducing polyvinyl chloride resin in a suspension or bulk polymeri-zation system. The alcohol can be added into the polymerization system either in a solution of initiator admixed with the desired alcohol or the alcohol and initiator added separately into the reaction vessel.
DETAILED DESCRIPTION OF THE INVENTION
The novel initiator composition of this invention consists essentially of certain azo and peroxide free radical initiators together with about 4.0 to 30~ by weight based on the initiator of one or more alcohols having the general structure R7-OH. R7 is saturated or unsaturated alkyl or aralkyl group of 8 to 20 carbons.
In the preferred alcohols, the R7 group contains from eight to about eighteen carbon atoms. The most preferred alcohols contain nine or ten carbons. Representative examples of alcohols include the fol-lowing: l-decanol; l-dodecanol; 2-octanol; l-octanol; l~octadecanol;
cumyl alcohol; oleyl alcohol; isodecyl alcohol.
The alcohols useful in the practice of this invention are further characterized in that ~hey could be primaryj secondary or tertiary alcohols. The commercially available long chain alcohols -5- f f ~f sometimes consist of a mixture oE two or more different isomers.
These alcohols are equally effective in the practice of this in-vention provided that the major constituent of such a mixture con-tains at least eight carbons. Further, a mixture of two or more separate long chain alcohols can be used wherein the total concen-tration of alcohols does not exceed about 30% by weight based on the initiator. The concentration of alcohol in the initiator is generally about 4.0 to 30~ by weight based on the weight of the initiator. The concentration of alcohol is always based on the weight of pure initiator in the composition.
In addition to the alcohol, the initiator composition can also contain other inert diluents such as odorless mineral spirits.
As is well known in the art, these inert diluents do not have any effect on the efficiency of free radical initiators.
The azo and peroxide free radical initiators which can b~ used in combination with the long chain alcohols to obtain the novel initiator compositions of this invention, include:
1) Free radical producing azo compounds represented by the general structure, Rl-C N=N-f-R4 X
wherein, X=alkyl of 1-10 carbons, aryl of 6-10 carbons, aralkyl of 7-15 .
. --'~ ~ carbons or cyano;
-i ~ Y = aryl of 6-10 carbons or cyano;
Rl, R2, R3 and R4 are independently selected from substituted or unsubstituted alkyl groups of 1 to 10 carbons (preferably l to 6 carbons) and cycloalkyl groups of 5 to 22 carbons (preferably 5 to i2 carbons). The substituents on Rl, R2, R3 and R4 can be aryloxy of 6-lO carbons, alkoxy of 1-10 carbons, acyloxy of 1-18-carbons, alkoxycarbonyl of 2-ll carbons, hydroxy, cyano, ¦~j carbamoyl, chloro, fluoro and carboxy.
lo Some of the preferred azo initiators include:

2-t-butylazo-2-cyano-4-methylpentane; 2-(t-butylazo~-iso-.
butyronitrile; 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane;

4-t-butylazo-4-cyanovaleric acid; 2, 2 ' -azo-bisisobutyronitrile;

2,2'-azo~bis-2, ~-dimethylvaleronitrile; azocumene;-and 2-(t-cumylazo) isobutyronitrile ' s' 2) Peroxydicarbonate initiators represented by the general i ,, .
structure, ., ,, . - - ~.

f~ ' ' ' ' '~t R5-O- -OO- C~-O-R5 vvherein R5 ls selected from a substituted 0! ur.substituted alkyl group of 2 to 22 carbons (preferred 2 to 12 carbons), cycloalkyl group of 5 to 22 carbons (preferred 5 to 12 carbons), aralkyl group - ' .~
of 7 to 22 casbons (preferred 7 to 12'carbons).' ~I
.

' , , When R5 is substitutod, the substituents can be ar~loxy of ~-10 carbons, alkoxy of l-lû carbons, acyloxy of 1-13 carbons, alkoxycarbonyl of 2-11 carbons, cyano, carbamoyl, chloro or r; ;o Some of the preferred peroxydicarbonate initiators include:
di-(2-ethylhexyl) peroxydicarbonate; dicyclonexyl peroxydicarbonate;
di- ( sec. -butyl ) peroxydicarbonate; dibenzyl peroxydicarbonate;
diisopropyl peroxydicarbonate; dicetyl peroxydicarbonate; and di(2-chloroethyl) peroxydicarbonate.
. 3) a-branched (or a -substituted) peroxyesters represented 10 by the general structure, ~ .,~ ~
O
'11 (RCOO) nR~
s~ ..
wherein:
a) n is 1 or 2 ~) when n is 1, R is s~ected from the group consisting of a . secondary or tertiary alkyl of 3 to 17 -carbons, cycloalkyl of 3 to - 12 carbons, l-arylalkyl of 7 to 20 carbons, l-alkoxyalkyl of 2 to 20 carbons, l-aryloxyalkyl of 7 to 20 carbons, l-haloalkyl of 1 to 20 carbons and l-cyanoalkyl of 2 to 20 carbons and R' is selected from the group consisting of tertiary alkyl of 4 to 12 carbons, tert-aralkyl of 9 to 18 carbons and tertiary cycloalkyl of 6 to 12 carbons.
- c) when n is 2, R is the same as above and R' is a di-tertiary dira~ical , j, .
~.

~13~

,, . . , -'-, ~ ~ selected from alkylene of 6 to 16 carbons, alkyny~ e Gf ~ 6 to 16 carbons, aralkylene of 12 to 18 carbons and cycloalkylene of 7 to 12 carbons.
Some of the preferred peroxyesters include~
. t-butyl peroxypivalate; ~-cumyl peroxypivalate;
t-amyl peroxypivalate; t-butyl peroxyneodecaate;
t-amyl peroxyneodecanoate; ~-cumyl peroxyneodecanoate, t-butyl peroctoate; t-amyl peroctoate; 1; 1, 3, 3-tetra~
methylbutyl peroxyneodecanoate; 2, 5-dimethyl-2, 5-lo di~pivaloylperoxy)hexane.
4) Diacyl peroxides represented, by the general structure, _ wherein: . -a) R6 and R'6 are independently selected from a substituted or unsubstituted primary alkyl group of 1 to 19 carbons wherein the substituent is selected from halogen, alkoxy of 1-4 ,~
carbons, and aryl of 6-10 carbons, phenyl or substituted phenyl wherei, the substituent is selected from halogen, " ' ' ' ' ' "' ~i ~.

~3~1;Z3 alkyl of 1 to 4 carbons, and alkoxy of 1 to 4 carbons,and b) when R6 is not equal to R'6, R6 is the same as above and R'6 can further be selected from the group consisting of: secondary alkyl of 3 to 17 carbons, cycloalkyl of

3 to 12 carbons, l-arylalkyl of 7 to 20 carbons, l-alkoxyalkyl of 2-20 carbons, l-aryloxyalkyl of 7 to 20 carbons, l-haloalkyl of 1 to 20 carbons and l-cyano-alkyl of 2 to 20 carbons.
Som~ of the preferred diacyl peroxides include:
isononanoyl peroxide; decanoyl peroxide; lauroyl per-oxide; acetyl 2-chlorobutyl peroxide; acetyl 2-chloro-decanoyl peroxide; benzoyl peroxide; 2,4-dichlorobenzoyl peroxide; and acetyl benzoyl peroxide.
Azo and peroxide free radical initiators used in the novel compositions of this invention will have a ten hour half-life temperature of abou~ 20 to 100C, preferably about 30 to 80C. The half-life temperature measurement is well known in the art and is dependent on factors such as solvent, concentration, pressure etc. We assume that the ten hour half-life temperature of free radical initiators is measured in a solvent such as ~benzene, toluene, trichloroethylene or odorless mineral spirits, wherein the initiator concentration is in the range of 0.05 to 0.2 moles per liter and at atmospheric pressure.
The ten hour half-life temperature of the initiators is used widely as a measure of initiator activity. In ~eneral, the " ,, -- 1 0 .. . .

3L~3~12~3 initiator activity increases with decreasing ten hour half-life temperatl~re. Thus, the specific choice of initiator is influenced by the polymerization temperature.
The novel initiator compositions of this invention can be used in either suspension or bulk polymerization of free radically polymerizable monomers. They are particularly useful for vinyl chloride homo- or co-polymerization in suspension or bulk systems. The general characteristics and features of suspension and bulk polymerization systems are well known in the art. See for example, "Processes for Major Addition Type Plastics and Their Monomers" by Lyle F. Albright, McGraw Hill Book Co., 1974, Chapter Six, Production of Polyvinyl Chloride Polymers.
When vinyl chloride (VC) is copolymerized with one or more monomers, the concentration of vinyl chloride is at least 60% based on total weight of monomers. A variety of monomers can be used in the co-polymerization and these are well known in the art. Some of the preferred monomers suitable for co-poly-meriza~ion with vinyl chloride include the following:
vinyl acetate; acrylic and methacrylic acids and their esters;
acrylonitrile; propylene; vinylidene chloride; maleic and fumaric acids, their es~ers and anhydrides; and vinyl e~hers.
The polymerization is generally conducted at constant temperatures, in the range o~ about 40 to 120C, preferably in the range of about 40 to 90C. The polymerization can also be .~

~' ' --- ...

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conducted in two or more distinct ~emperature stages. If necessary a ~ontinuously increasing temperature profile can be used. These and other changes do not have a marked effect on the basic objectives of the invention.
When the polymerization is conducted in aqueous sus-pension medium, the pH of the aqueous phase can be adjusted by adding buffers to ohtain maximum initiator efficiency. Thus, when using peroxydicarbonates or diacyl peroxides, it is pre-~erred to run the polymerization under neutral or acidic pH
conditions. Where necessary, alkaline pH conditions can also be used with some sacrifice in initiator efficiency. This loss in efficiency is observed where the initiator is susceptible to alkaline hydrolysis. With peroxyester initiators, the pH of the aqueous phase is not important e~cept when ~-cumyl peroxyesters are ~lsed which are acid sensitive and thus should be preferably used under neutral or alkaline conditions. The azo compounds can be used over a wide range of Ph without significant loss in efficieney. The objeetives of this invention are not direetly effeeted by the pH~ In general, one skilled in the art ean easily determine the desired pH conditions to obtain the hest results.
The no~el initiator eompositions can be used alone or in eom~inations (two or more) wherein the total initiator eoncentra-tion is in the range of about 0.005 to 0.25 parts hy weight per 100 parts by weight of monomer. A particularly preferred range is from 0.025 to 0.20 parts per 100 parts of monomer.
The novel initiator compositions of this inven~ion can also be used in combination with one or more other free radical initiators. When a combination of initiators is used, the selec-tion of the individual components is influenced by factors such as polymerization temperature, the desired polymerization rate and the available cooling capacity. In general, the individual components will have different ten hour half-life temperatures and the difference in ten hour half-life temperatures is at least 2C, preferably 5 to 15C (measured in the same solvent).
The ratio of the individual components (pure weight basis) can be conveniently adjusted to obtain the desired rate of polymerization. Thus the first component of the initiator mix-ture is 5 to 95% of the total initiator concentration and is preferably from 10 to 85% of the total.
The novel initiator compositions of this invention can also be used in combination with one or more other free radical initiators. Among these, sulfonyl peroxides are particularly preferred. Examples of these include acetyl cyclohexylsulfonyl peroxide and acetyl secondary-heptylsulfonyl peroxide.
Although the following examples illustrate the invention as a batch reaction, the invention can also be practiced as a continuous or semi-continuous polymerization reaction.

;,,, ~' .

~.3~ 3 Abbreviations used ln the Examples:
VC...... vinyl chloride monomer TBPN.... t-butyl peroxyneodecanoate*
ACPN.... .~ -cumyl peroxyneodecanoate DSBP.... di(sec.-butyl) peroxydicarbonate ACPP.... .q -cumyl peroxypivalate DCB..... 2,4-dichlorobenzoyl peroxide BC~MP... 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane ~I] ... concentration of initiator at the start of a poly-merization phm..... parts by weight per hundred parts of monomer *The term neodecanoate is defined in U.S. Patent #3,624,123, Experimental Procedure Suspension Polymerizations Polymerization of VC in suspension was carried out in a 1~5 liter reactor, which was designed and instrumented such that the polymerization could be monitored calorimetrically. The reactor was immersed in a water bath, maintained 0.5C a~ove the desired reaction temperature, thus preventing any heat loss to the surroundings. The heat produced fxom the exothermic poly-merization, plus the heat passed in~o the reactor from the water bath, were removed by the passage of cooling water through internal coils in the reactor. Thus, the temperature was kept constant. The flow rate of the cooling water, and the tempera-ture difference between :: ' ~ ~ 3 ~

entrance and exit streams were monitored; hence, a continuous recording of heat removed (cal. min 1) was obtained.
The pressure in the reactor was also continuously monitor-ed. At about 70% conversion of monomer to polymer, the monomer in the vapor phase became depleted and the pressure started to fall.
Hence, from a knowledge of the point of 70% conversion, and the heat of polymerization of VC (23 kcal/mole), it was possible to calculate the"background count" in the calorimetric recording;
the background is due to heat flow from the water bath to the re-actor. By subtracticn, the true rate of polymerization (cal. min 1 as a function of time, was obtained.
Su~eension Systems Used System A (pH about 6.5) 1% solution of Aerosol MA 80%*42 ml 1% solution of Methocel F 50**168 ml Triply distilled water 469 ml * Trademark for Surfactant made by American Cyanamid Co. (sodium dihexyl sulfosuccinate) ** Trademark for a Hydroxypropyl methyl cellulose polymer made by Dow Chemical System B (Buffered to pH = 8.0) System A plus 0.105g of sodium bicarbonate ~' ~''''' ''' ' '" . ^

2~3 , ~ .
~ - 16 -System C (Buf~ered to pfI = 10. 0~
, 1% solution of Methocel F 50 200 ml . Triply distille,d water 500 ml sodium bicarbonate 1. 47g _ --sodium car~)onate 1. 85g Note: pH of the aqueous phase was measured at ambient temperatures, about 22C, using a standard pH meter.
EXAMPLE I ~ !i Effect of Alcohols on VC Polvmerization usir. TBPN as Initiator 0 In all cases [ I ~ was 0. 125 phm and the polymerization . ten~ erature wa s 5 5 C. The alcohol concentra tion wa s fixed at 3()% w/w on [ I lo and suspension systern B was used throughout.
Table 1 Run~ _ Alcohol _ Tlrne to ~ressure droD (mins, ) none . 300 ,.
- - 2 Octan-2 -ol - 2 60 . . 3 Cumyl alcohol 225

4 ~ Decan- 1-ol 210 Dodecan-l -ol 230 6 Octadec~n-1-ol 230 7 Oleyl alcohol . 270 Table shows that all of the alcohols exerted sorne .

.

~;- = - - l 7 -~' -- ' ' .
~--.... =accelerating influence on the polyrnerization rate, decan-l-I . ol being the most effective. Examination of the polymeriza-tlon rate data for runs 1 and 4 ln Table 2 shows that the '-inltial rate was increased more than that in the later stages;
this was true for most though not all, of our experimental polymeriza tions.

- . ?

.

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2~3 ~,~ ~~r) ~ N
U

~ U30 0 0 0 0 0 0 rl rl ~ ~ ~ ~ ~J N t~l U~ D ~ 00 ~1 N CO O O ~ '* ~ O

C~

a~ ~
~:OOOOOOOOOOOOOOOOOOOO

E~ ~ ., ~ o ~ ~ ~ ~ r~ D O
l N t~ I ~ N ~I N t~l ~I t'`l V
o _. rl a~ tO
O O O O O O O O O O O O
h O
D~
O GO ~D ~r ~ 'P co o ~ o o o u~
$
~;

~OOOOOOOOOOr~ O
.,1 ~ ~1.
E~

'` 18 ~3~ 3 Fouling of the stirrer and the reactor coils was reduced in the presence of the alcohols.
Samples of the polymer from runs 1 and 4 were subjected to particle size analysis using an Electrozone* computerised particle data processing system (Particle Data Inc.). The polymer from run #l has a very broad particle size distribution, heavily skewed towards large particle sizes and two maxima at about 100 and 200 microns. By contrast the polymer from run #4 has a narrow near Gaussian distribution of particle sizes centered on about 100 microns.
E~AMPLE 2 Effect of Cumyl Alcohol on VC Polymerization Initiated by ACPN
In all cases, suspension system C was used at 50C with ~I~o 0.15 phm. The time to pressure drop was measured as a function of the cumyl alcohol concentration, expressed as a per-centage ~w/w) on ~I~o cymyl alcohol time to pressure drop wt, ~ as initiator minutes 4.6 355 9.6 340 19.6 320 34.6 310 54.6 320 !

*Trademark !

, ~ . ,.

1.3Z~LZ3 Table 3 shows that the polymerization rate was accelerated by the cumyl alcohol, reaching a limiting value at about 20-30%
alcohol w/w on [I] O. Polymerization rate enhancement does occur at alcohol concentrations above 35~; when too much alcohol is used, however, the particle size becomes too fine which creates a dusting problem.

Effect of ~ecan-l-oI on the Polymerization of VC Initiated by BCMMP
Polymerizations were conducted at 60C using suspension system A.
With ~I] O 0.055 phm, BCMMP gave a pressure drop in 400 minutes.
The addition of 30% decan-l-ol (w/w) on ~I] O reduced the time to pressure drop to 330 minutes. Once again it was noted that less fouling occurred in the presence of the alcohol; this appears to be a quite general effect of alcohol addition.

Effect of Decan-l-ol on the Polymerization of VC Initiated by DSBP
Polymerizations were conducted at 55C using suspension system A.

With [I] O 0.05 phm DSBP ga~e a pressure drop in 320 minutes.
The addition of 50% decan l ol ~w/w) on [I~ O reduced the time to pressure drop to 300 minuteC.

~....
~, ~3~ 3 Effect of Decan-l-ol on the Polymerization of ~C Initiated by DCB
Polymerizations were conducted at 60C using suspension system C.
r ~
With LIJ O = 0.175 phm DCB gave a pressure drop in 280 minutes, the addition of 30% decan-l-ol (w/w) on [I] O reduced the time to pressure drop to 250 minutes. In this example the reduction of reactor fouling in the presence of the alcohol was very marked.

Effect of Dodecan-l-ol on the Polymerization of VC Initiated by a Combination of TBPN and ACPP
Polymerizations were conducted at 55C using suspension system C.
TBPN t [I ~ O . 06 phm) plus ACPP ( [I~ 0.075 phm) gave a o o pressure drop in 250 minutes. The addition of 30% dodecan-l-ol _ ~
(w/w) on total IJ O reduced the time to pressure drop to 210 minutes.

:,, , ~' ;~ ' ' ' EX~MPLE 7 Effect of dodecan-l-ol on the Polymerization of VC Initiated by a Combination of TBPN and ACPN
Polymerizations were conducted at 55C using suspension system C.
TBPN ( [I] O 0.05 phm) used in combination with ACPN ( [I] O
0.075 phm) gave a pressure drop in 280 minutes. The addition of 25% dodecan-l-ol (w/w) on total [I~ O reduced the timejto pressure drop to 230 minutes. The ACPN initiator sample contained about 5% cumyl alcohol~

Effect of Decan-l-ol on the Bulk Polymerization of VC Initiated The polymerization was conducted in a standard reactor system at a temperature of 54+2 C with LI ] O = O. 037 phm. A conversion of about 70% was obtained after about 400 minutes. The experi-ment was repeated but with the addition of 30% decan-l-ol (w/w) on [I~ O and in this case 70~ conversion was obtained after only 300 minutes. The polymers from both experiments were analyzed for particle size distribution. The results were as follows:
% Scale > 40 mesh <40 mesh ~ (%) (~) Without alcohol 19 32 49 With alcohol 13 11 76 ~3'~3 Thus, the addition of alcohol has effected a larye reduction in particle size and also reduced the amount of scale formed.

Suspension Polymerization of VC Initiated by a Combination of Acetyl Sec.-Heptylsulphon~l Peroxide (AHSP) and O~-Cumyl Peroxypivalate (ACPP)* Containiny Cumyl Alcohol.
The polymerization was conducted at 55C using suspension system C. The ACPP sample contained 8.8 wt% cumyl alcohol.
ACPP ( CI] )O 0.08 phm (pure basis)) used in combination with AHSP ([I~o 0.012 phm) gave a pressure drop in 290 minutes.
This system is more effi¢ient than ACPP used alone, of which 0.15 phm are required to give a pressure drop in 250 minutes under the same conditions. Furthermore the polymerization rate due to ACPP
alone increases with conversion whereas the ACPP/AHSP combination gives a more nearly constant polymerization rate vs. time dependence.
Thus use of the combination could make more efficient use of the reactor cooling capacity. The reactor was quite clean at the end of the polymerization, showing only very light deposits on the metal surfaces.
* Lupersol (Trademark) 47 M75 used as a 75% solution in odorless mineral spirits.

' , ' 1~32123 Suspension Polymerization' of VC Initiated by a Combination of Acetyl Cyclohexylsulphonyl Peroxide (ACSP) *'-and ~ -Cumyl Peroxypivalate (ACPP) ** Cont-ainin'g Cumy1 Alcohol.
The polymerization was conducted at 55C using suspension system A. The ACPP sample contained 8.8 wt% cumyl alcohol.
ACPP ( CI~o 0.66 phm (pure basis)) used in combination with ACSP ( CI~O 0. 018 phm) gave a pressure drop in 250 minutes.
The rate of polymerization was very steady, and the reactor sur-faces were quite clean at the end of the reaction; there being only a very light film coating on the metal surfaces.
* Lupersol *228Z used as a 30~ solution in dioctyl phthalate.
** Lupersol *47 M75 used as a 75% solution in odorless mineral spirits.

* Trademark 3~1~3 Suspension Polymerizatlo'n o'f VC Initia'ted'b~ a Combination of Di-(2-Ethylhexyl) Per_xydicarbonate (EHP)* an-d ~-Cumyl-Peroxy-neodecanoate (ACPN)** Containing Cumyl Alcohol.

. .
The polymerization was conducted at 55C using suspension system C. ~he ACPN sample contained 4.6 wt% cumyl alcohol.
ACPN (tI~o 0.075 phm (pure basis)) used in combination with EHP ( LI]O 0.038 phm) gave a pressure drop in 290 minutes.
The rate of polymerization was quite steady with respect to time, and the reactor surfaces showed only very light deposits at the end of the run.
* Lupersol *223 M75, a 75% solution of Di-(2-ethylhexyl) peroxydi-carbonate in odorless mineral spirits.
** Lupersol *188 M75, a 75% solution of a-cumyl peroxyneodecanoate in odorless mineral spirits.
!

* Trademark A

Claims (21)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An initiator composition for suspension or bulk poly-merization of vinyl chloride consisting essentially of 0.005 to 0.25 parts by weight per 100 parts by weight of monomer of an initiator selected from the class consisting of a free radical producing azo, peroxydicarbonate, .alpha.-branched peroxyester, diacyl peroxide and mixtures thereof, and 4.0 to 30% by weight based on the initiator of one or more alkyl or aralkyl alcohols of 8 to 20 carbons.

2. An initiator composition for suspension or bulk poly-merization of vinyl chloride, consisting essentially of 0.005 to 0.25 parts by weight per 100 parts by weight of monomer of a compound selected from the group consisting of , , , , and mixtures thereof wherein:
a) X is an alkyl of 1-10 carbons, aryl of 6-10 carbons, aralkyl of 7-15 carbons or cyano;
b) Y is an aryl of 6-10 carbons or cyano;
c) R1, R2, R3 and R4 are independently selected from an alkyl of 1-10 carbons and cycloalkyl of 5-22 carbons;
d) R5 is selected from an alkyl of 2-22 carbons, cycloalkyl of 5-22 carbons, and aralkyl of 7-22 carbons;
e) n is 1 or 2 f) when n is 1, R is selected from secondary or tertiary alkyl of 3-17 carbons, cycloalkyl of 3-12 carbons, l-arylalkyl of 7-20 carbons, l-alkoxyalkyl of 2-20 carbons, l-aryloxyalkyl of 7-20 carbons, l-haloalkyl of 1-20 carbons and l-cyanoalkyl of 2-20 carbons and R' is selected from tertiary alkyl of 4-12 carbons, tert-aralkyl of 9-18 carbons and tertiary cycloalkyl of 6-12 carbons;
g) when n is 2, R is the same as in f) and R' is a di-tertiary diradical selected from alkylene of 6-16 carbons, alkynylene of 6-16 carbons, aralkylene of 12-18 carbons and cycloalkylene of 7-12 carbons;
h) R6 and R'6 are independently selected from a primary alkyl of 1-19 carbons, phenyl, or substituted phenyl wherein the substituent is selected from halogen, alkyl of 1-4 carbons and alkoxy of 1-4 carbons; and i) when R6 is not equal to R'6, R6 is the same as in h) and R'6 can further be selected from a secondary-alkyl of 3-17 carbons, cycloalkyl of 3-12 carbons, l-arylalkyl of 7-20 carbons, l-alkoxy-alkyl of 2-20 carbons, l-aryloxyalkyl of 7-20 carbons, l-haloalkyl of 1-20 carbons and l-cynaoalkyl of 2-20 carbons; and 4.0 to 30%
by weight based on the initiator of one or more alcohols having the formula R7-OH wherein R7 is a saturated or unsaturated alkyl of 8-20 carbons or aralkyl of 8-20 carbons.

3. The initiator composition of claim 2 wherein the alcohol is selected from the group consisting of octan-2-ol, cumyl alcohol, decan-l-ol, dodecan-l-ol, octadecan-l-ol, oleyl alcohol and mixtures thereof.

4. The initiator composition of claim 3 wherein the compound is selected from the group consisting of t-butyl peroxy-neodecanoate,.alpha.-cumyl peroxyneodecanoate, di(sec.-butyl) peroxydi-carbonate,.alpha.-cumyl peroxypiyalate, 2,4-dichlorobenzoyl peroxide, 2-t-butylazo-2-cyano-4-methoxy-4-methyl-pentane and mixtures thereof.

5. The composition of claim 2 wherein the compounds is a combination of .alpha.-cumyl peroxyneodecanoate and .alpha.-cumyl peroxy-pivalate.

6. The composition of claim 2 wherein the compound is a combination of t-butyl peroxyneodecanoate and .alpha.-cumyl peroxy-neodecanoate.

7. The composition of claim 2 wherein the compound is a combination of t-butyl peroxyneodecanoate and .alpha.-cumyl peroxy-pivalate.

8. The composition of claim 2 wherein the compound is a combination of di(2-ethylhexyl) peroxydicarbonate and .alpha.-cumyl peroxyneodecanoate.

9. The initiator composition of claim 2 wherein the one or more alcohols have 9 or 10 carbons.

10. The initiator composition of acetyl sec.-heptylsul-phonyl peroxide, .alpha.-cumyl peroxypivalate and 4.0 to 30% by weight based on initiator content of one or more alcohols having the formula R7-OH wherein R7 is a saturated or unsaturated alkyl of 8-20 carbons or aralkyl of 8-20 carbons.

11. The initiator composition of acetyl cyclohexylsul-phonyl peroxide, .alpha.-cumyl peroxypivalate and 4.0 to 30% by weight based on initiator content of one or more alcohols having the formula R7-OH wherein R7 is a saturated or unsaturated alkyl of 8-20 carbons or aralkyl of 8-20 carbons.

12. In a method of producing polyvinyl chloride resin in a suspension or bulk polymerization system comprising poly-merizing vinyl chloride in the presence of an initiator, the improvement comprising using the initiator composition of claim 2.

13. The method of claim 12 wherein the alcohol is as defined in claim 3.

14. The method of claim 12 wherein the compound is as defined in claim 4 and the alcohol is as defined in Claim 3.

15. The method of claim 12 wherein the compound is a combination of .alpha.-cumyl peroxyneodecanoate and .alpha.-cumyl peroxy-pivalate.

16. The method of claim 12 wherein the compound is a combination of t-butyl peroxyneodecanoate and .alpha.-cumyl peroxyneode-canoate.

17. The method of claim 12 wherein the compound is a combination of t-butyl peroxyneodecanoate and .alpha.-cumyl peroxypivalate.

18. The method of claim 12 wherein the compound is a combination of di(2-ethylhexyl) peroxydicarbonate and .alpha.-cumyl peroxyneodecanoate.

19. In a method of producing polyvinyl chloride resin in a suspension or bulk polymerization system comprising polymerizing vinyl chloride in the presence of an initiator, the improvement comprising adding 0.005 to 0.25 parts by weight per 100 parts by weight of monomer of a combination of acetyl sec.-heptylsulphonyl peroxide and .alpha.-cumyl peroxypivalate and 4.0 to 30% by weight based on the initiator of one or more alkyl or aralkyl alcohols of 8 to 20 carbons.

20. In a method of producing polyvinyl chloride resin in a suspension or bulk polymerization system comprising polymerizing vinyl chloride in the presence of an initiator, the improvement comprising adding 0.005 to 0.25 parts by weight per 100 parts by weight of monomer of a combination of acetyl cyclohexylsulphonyl peroxide and .alpha.-cumyl peroxypivalate and 4.0 to 30% by weight based on the initiator of one or more alkyl or aralkyl alcohols of 8 to 20 carbons.

21. In a method of producing polyvinyl chloride resin in a suspension or bulk polymerization system comprising polymerizing vinyl chloride in the presence of an initiator, the improvement comprising adding 0.005 to 0.25 parts by weight per 100 parts by weight of monomer of at least one initiator selected from the class consisting of a free radical producing azo, peroxydicarbonate, .alpha. -branched peroxyester, diacyl peroxide and mixtures thereof, and adding 4.0 to 30% by weight based on the initiator of one or more alkyl or aralkyl alcohols of 8 to 20 carbons.