DD254946A1 - PROCESS FOR PREPARING POLYMERS OF VINYL CHLORIDE - Google Patents

Abstract

The invention relates to a process for the preparation of polyvinyl chloride by the suspension method with high sheeting weight and good porosity. The process is designed in such a way that polysiloxane-polyoxyalkylene block copolymers of the general formulas R 3 SiO & SiO! M & SiR 20! NSiR 2G (I) Goder GR 2 SiO & SiRO! M & SiR 2 O! N / 2 - SiR 2G (II) O & SiR are used as suspension stabilizers 2! Goder R 3SiO & SiRO! M / 3 & SiR 2O! N / 2 & SiRO! M / 3 SiR 3 (III) O & SiR 2! N / 2 O & SiRG! M / 3 O SiR 3worine mean: R - same or different lower, if necessary substituted alkyl radicals; preferably methyl groups-integers or fractions between 1 and 12, preferably between 2 and 5n-integers or fractional numbers between 30 and 250, preferably between 40 and 120G-polyoxyalkylene of the general formula & CH 2! 3 & OHCH 2CH 2! p & OCH 2 CH (CH 3)! qOHp, q - Whole or fractional numbers between 4 and 50in concentrations between 0.001 and 0.3 wt .-% based on the aqueous phase can be used.

Description

It is also known, by adding long-chain fatty acids or their esters or by adding ionic or nonionic surfactants, often combined with other additives, such as reducing agent to the polymerization to increase the plasticizer receptivity (DE-OS 2385134,2151703, DE-PS 1 545 179, DE-OS 2244805.2134804).

Also described is the combination of suspension stabilizers for influencing the plasticizer receptivity (US Pat. No. 3,879,365, DE-AS 1720238, DE-OS 2209892).

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 13583.24358).

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, i. 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 invention is based on the object ₍ to develop a process for the preparation of polymers of vinyl chloride by radical polymerization of vinyl chloride and predominantly polyvinyl chloride-containing monomer mixtures using known radical-forming initiators or initiator systems and optionally known Polymerisationisationshiifsstoffen after the suspension process.

The object is achieved according to the invention in that, as suspension stabilizers, polysiloxane-polyoxyalkylene block copolymers of the general formulas _%

Rs [SiO [SiROUSiRsO] _n SiRs (I)

G or

GRzSiO [SiRO] _n , [SiRzO] _n Z ₂ - SiR ₂ G (H)

R ' ₃ Si0 [SiR'O] _{m / 3} [SiR ₂ OW ₂ [SiROW ₃ SiR ₃

JiR

in which mean:

R 'same or different lower, optionally substituted alkyl radicals; preferably methyl groups m- Whole or fractional numbers between 1 and 12, preferably between 1 and 12, preferably between 2 and 5 η - Whole or fractional numbers between 30 and 250, preferably between 40 and 120 G polyoxyalkylene of the general formula [ CH ₂ I ₃ - [OCH ₂ CH ₂ ] P- [OCH ₂ CH (CH ₃ ) Iq-OH p, q Whole-modulated numbers between 4 and 50

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

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

embodiments Example 1 to 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 part of dicetyl peroxydicarbonate and the amounts of polysiloxane-polyoxyalkylene block copolymers (PPB) according to Tab.

 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 peroxide carbonate, 0.15 part of lauroyl peroxide and 0.05 wt%, based on the water, of polysiloxane-polyoxyalkylene block copolymers

 It was polymerized at 70 ° C.

Example 6

An oxygen-free rinse autoclave was charged with 400 parts of water, 200 parts of vinyl chloride, 0.25 part of dicetyl 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 to 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 of dicetyl peroxydicarbonate and the amounts of additives contained in Tab. 2.

Table! PPB bulk centrifuge 5 middle distribution K value Ex. Wt .-% mass softener grain wide F. bez. a. H ₂ O g / i admission% messerum 0.3 562 24.2 146 1.52 62.4 1 0.15 581 23.7 143 1.61 62.7 2 0,075 605 23.6 157 1.52 62.4 3 0.05 612 22.2 161 1.49 62.5 4 0.05 643 18.1 159 1.57 58.4 CJL 0.05 576 27.1 138 1.63 67.8 6 c - mean grain diameter of the Gaussian distribution

d - grain diameter

G - Sum weight of the sieve fraction

Table 2

additive

Concentration wt .-% bez. a. monomeric

bulk weight

g / i

centrifuge

softener

admission%

mean grain diameter

Distribution width F

7 sorbitol monolaurate 0.04

8 oleic acid glycerol ester 0.12

9 octadecyl alcohol / 0.08 oleic acid ester 0.08

c - mean grain diameter of the Gaussian distribution F - distribution width, which is calculated according to F =

d - grain diameter

G - Sum weight of the sieve fraction

GD95

620 638 539

1.68 1.72 1.69

1.75 1.84 1.81

Claims (2)

1. A process for the preparation of polymers of vinyl chloride by free-radical polymerization of vinyl chloride and predominantly vinyl chloride-containing monomer mixtures using known radical-forming initiators or initiator systems and the suspension process, characterized in that as suspension stabilizers polysiloxane-Pplyoxyalkylen block copolymers of the general formulas, R ₃ SiO [SiROUSiR ₂ O] _n SiR ₃ (I) G
or GR ^ SiO [SiRO] _m [SiR ₂ O] _{n / 2} - € ifl ' ₂ G (II) R ₃ SiO [SiR'O] _{m / 3} [SiR ₂ O] _{n / 2} [SiRO] _{m / 3} SiR ₃ > iR ₂ ] _n / ₂
>iR'G] _m / 3 in which mean: R 'same 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 of the general formula
- [CH ₂ ] ₃ - [OCH ₂ CH ₂ ] _p - [OCH ₂ CH (CH ₃ )] _q -OH
p, q - integers or fractions between 4 and 50 in concentrations between 0.001-0.3 wt .-% based on the aqueous phase is used. 2. The method according to item 1, characterized in that said polysiloxy-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 chlorides 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 profile 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, or the thermal stability of the polymer. For the processing of the polyvinyl chloride, particularly the bulk density and the plasticizer capacity are of crucial importance. However, both properties are related in such a way that usually in the improvement of one size deterioration of the other occurs. As dispersants u.a. Cellulose ethers, as described in DE-OS 2412014, 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), (3438328).