DD251147A1 - PROCESS FOR PREPARING POLYMERS OF VINYL CHLORIDE - Google Patents

Abstract

The invention relates to a process for the preparation of polymers of vinyl chloride by the suspension method with high bulk weight and good porosity. The process is designed so that, as suspension stabilizers, polysiloxane-polyoxyalkylene block copolymers of the general formulas (I), (II), (III) in which: R - are identical or different lower, optionally substituted, alkyl radicals; preferably methyl groups; m - integers or fractions between 1 and 12, preferably 2 and 5; n - whole or fractional numbers between 30 and 250; preferably between 40 and 120; G - polyoxyalkylene glycol acetate, alkoxylate, cyanoalkoxylate or ureate radical of the general formula (CH 2) 3 (OCH 2 CH 2) p (OCH 2 CH (CH 3)) q R R OCOCH 3, OCH 3, OC 4 H 9, OCH 2 CH 2 CN, OCONHRR alkyl or aryl radical, q whole or fractions between 4 and 50 in concentrations between 0.001 and 0.3% by weight, based on the aqueous phase. Formula (I), (II) and (III)

Description

GR ₂ SiO

R ₃ SiO Z ~ SiR'0j _{m / 3} Z ~ SiR £ 0j _{n / 2} Z ~ SiR'Oj

0 SiR ₃

in which mean:

R '- identical or different lower, optionally substituted alkyl radicals; preferably methyl groups m - integers or fractions between 1 and 12, preferably between 2 and 5 η - integers or fractions between 30 and 250, preferably between 40 and 120 G - polyoxyalkylene glycol acetate, alkoxylate, cyanoalkoxylate or ureate radical of the general formula

- [CH ₂ ] ₃ - [OCH ₂ CH ₂ ] p- [OCH ₂ CH (CH ₃ )] _q -R '

R'-OCOCHs, -OCH ₃ , -OC ₄ H ₉ , -OCH ₂ -CH ₂ CNrOCONHR "

R "is alkyl or aryl radical

p, q whole or fractional numbers between 4 and 50

in concentrations between 0.001-0.3 wt .-% based on the aqueous phase can be used. 2. The method according to item 1, characterized in that said polysiloxane-polyoxyalkylene block copolymers in combination with known surface-active substances, such as cellulose derivatives, fatty acid sulfonates, sorbitol or fatty acid esters u.a. be used.

Field of application of the invention

The invention relates to a process for the preparation of polymers of vinyl chloride by radical polymerization of vinyl chloride and predominantly vinyl chloride-containing monomer mixtures by the suspension process.

Characteristic of the known technical solutions

The suspension polymerization of vinyl chloride or the preparation of copolymers based on vinyl chloride is carried out on an industrial scale in the presence of dispersants for the preparation and stabilization of the vinyl chloride / polyvinyl chloride suspension in the aqueous phase. It determines u.a. the property of the dispersant system, the distribution of the monomer in the aqueous phase, the morphology of the PVC grain, in particular its porosity, the particle size distribution, but also the thermostability of the polymer. For the processing of the polyvinyl chloride, particularly the bulk density and the plasticizer capacity are of crucial importance. Both properties are related so that, as a rule, the improvement of one size leads to a deterioration of the other.

As dispersants u.a. Cellulose ethers, as described in DE-OS 2412014 are in question. Furthermore, cellulose ethers in a mixture with partially hydrolyzed polyvinyl acetate (DD-PS 145539) or with polyvinyl acetate (DE-AS 1142238) are optionally used in conjunction with nonionic emulsifiers (DE-OS 2945073). To achieve high porosities, additional aliphatic or aromatic hydrocarbons or alcohols are used (US Pat. No. 2875186, US Pat.

It is also known, by adding long-chain fatty acids or their esters or by adding ionic or non-ionic surface-active substances, often combined with other additives, such as reducing agent to the polymerization mixture to increase the plasticizer receptivity (DE-OS 2365134, 2151703, DE-PS 1545179, DE-OS 2,244,905.2143604).

Also described is the combination of suspension stabilizers for influencing the plasticizer receptivity (US Pat. No. 3,879,365, DE-AS 1 720328, DE-OS 2209592).

A polyvinyl chloride having a high bulk density, low porosity and a relatively broad particle size distribution is obtained when using styrene / maleic anhydride copolymers as a dispersant (DD-PS 13583.14358).

Furthermore, a polyvinyl chloride having a relatively high bulk density and a good porosity by addition of diallyl or triallyl compounds to the commonly used dispersants or their mixtures (DD-PS 151455).

The known methods have the disadvantage that they affect only one size positively and the others are neglected, d. H. With a high bulk density, one obtains low porosities or vice versa.

Due to the large number of additives, it is often necessary to reduce the deterioration of other product properties, such as i.a. Take the thermal stability into account.

Object of the invention

The aim of the invention is the production of polyvinyl chloride with high bulk density and good porosity by the suspension process.

Explanation of the essence of the invention

The object of the invention is to develop a process for the preparation of polymers of vinyl chloride by radical polymerization of vinyl chloride and predominantly vinyl chloride-containing monomer mixtures using known radical-forming initiators or initiator systems and optionally known polymerization auxiliaries by the suspension process.

The object is achieved in that the suspension stabilizers polysiloxane-polyoxyalkylene block copolymers of the general formula

Ri ₁ SiO / "SiR'0 7 _m /" SiRAO J _n SiRi,

D - ι - III - eL - Xl _5

GR'SiO / "SiRΌ 7 _m /" SiRAO 7., / Q- SiRAG

(ID

0 G

O ι

0 SiR ₃ "

in which mean:

R '- identical or different lower, optionally substituted alkyl radicals; preferably methyl groups m - integer fractional numbers between i and 12, preferably between 2 and 5 η - integers or fractions between 30 and 250, preferably between 40 and 120 G - polyoxyalkylene glycol acetate, alkoxylate, cyano alkoxylate or ureate radical of the general formula

[CH ₂ ] 3- [OCH ₂ CH ₂ ] p- [OCH ₂ CH (CH ₃ )] _q -R '

R '-OCOCH ₃ , -OCH ₃ , -OC ₄ H ₉ , -OCH ₂ -CH ₂ CN, -OCONHR "

R "is alkyl or aryl radical

p, q whole or fractional numbers between 4 and 50

in concentration between 0.001-0.3 wt .-% based on the aqueous phase can be used.

The said polysiloxane-polyoxyalkylene block polymers can also be used in combination with known surface-active substances, such as cellulose derivatives, fatty acid sulfonates, sorbitol or fatty acid esters and the like.

embodiments Example 1-4

An oxygen-free rinse autoclave was charged with 400 parts of water, 200 parts of vinyl chloride, 0.15 parts of lauroyl peroxide, 0.1 parts of dicetyl peroxydicarbonate and the amounts of polysiloxane-polyoxyalkylene block copolymers (PPB) according to Table 1. Polymerization was at 63 ° C.

Example 5

An oxygen-free rinse autoclave was charged with 400 parts of water, 200 parts of vinyl chloride, 0.025 part of dicetyl peroxydicarbonate, 0.15 part of lauroyl peroxide and 0.05 wt% based on the water polysiloxane-polyoxyalkylene block copolymers. Was polymerized at 7O ⁰ C.

Example 6

An oxygen-free rinse autoclave was charged with 400 parts of water, 200 parts of vinyl chloride, 0.25 part of dicethyl peroxydicarbonate, 0.14 part of lauroyl peroxide and 0.05 wt% based on the water polysiloxane-polyoxyalkylene block copolymers. Polymerization was at 58 ° C.

Example 7-9

An oxygen-free rinse autoclave was charged with 400 parts of water, 200 parts of vinyl chloride, 0.15 parts of lauroyl peroxide, 0.1 parts Dicethlperoxidicarbonat and Table 2 contained amounts of additives.

Table 1 example

PPBGew .-% rel. to H ₂ O

bulk weight

centrifuge

softener

admission(%)

Average grain diameter distribution (/ im)

K value

1 0.3 557 25.5 which calculates after 140 7 d 5 1.58 62.7 2 0.15 585 23.9 120  Rl - \ f__. " d 95 1.54 62.7 3 0.075 600 23.6 166 \ G 1.44 62.9 4 0.05 615 22.7 158 1.52 62.8 CJL 0.05 650 17.5 163 1.62 58.1 6 0.05 573 27.4 131 1.72 67.9 C - mean grain diameter of the Gaussian distribution F - distribution width of the Gaussian distribution, G - Sum weight of the sieve fraction

Table 2

example additive concentration Bulk weight centrifuge softener medium grain distribution Wt .-% bez.auf admission (%) diameter width the monomer 17.5 7 sorbitan 0.04 620 18.6 169 1.70 8th Olsäureglycerinester 0.12 650 28.6 189 1.95 9 octadecylalcohol 0.08 531 173 1.91 Olsäureglycerinester 0.08

Claims (1)

Invention claim: A process for the preparation of polymers of vinyl chloride by radical polymerization of vinyl chloride and monomer mixtures containing predominantly using known radical-forming initiators or initiator systems and the suspension process, characterized in that as suspension stabilizers polysiloxane-polyoxyalkylene block copolymers of the general formulas / ~ SiR'0_7 _m /