DD257433A1 - PROCESS FOR PREPARING POLYMERS OF VINYL CHLORIDE - Google Patents

Abstract

The invention relates to a process for the production of high porosity and high lube weight polyvinyl chloride with a reduction in the formation of Wandansaetzen by the suspension process. The process is designed so that polysiloxane-polyoxyalkylene block copolymers are used as suspension stabilizers and 0.001 to 0.1% by weight, based on the aqueous phase, of salts or compounds of the 1 to 3 main groups, alone or in combination, are used for the polymerization batch. It will u. a. Sodium chloride, magnesium chloride and magnesium hydroxide used.

Description

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 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 worsening the other

entry. ,

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). In order to achieve high porosities, additional aliphatic or aromatic hydrocarbons or alcohols are used (US Pat. No. 2875186), (US Pat. No. 3,488,328).

It is also known, by adding long-chain fatty acids or their esters or by the addition of ionic or nonionic surfactants, often combined with other additives, such as reducing agent to the polymerization mixture to increase the plasticizer receptivity (DE-OS 2365134.2151 703, DE-PS 1545179, DE-OS 2244905.2134604).

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 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 13583.14358).

To reduce wall deposits and to reduce specks organic or inorganic alkali or alkaline earth metal and other metal salts are added to the reaction mixture in relatively high concentrations (DD-PS 37184.129088, DE-OS 2637582, 2225236).

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 to produce a polyvinyl chloride with high bulk density in good porosity by the suspension process with a reduction of Wands approaches.

Explanation of the essence of the invention The technical problem which is solved by the invention

The object of the invention is to develop a process for the suspension polymerization of vinyl chloride or predominantly vinyl chloride-containing monomer mixtures, which makes it possible to prepare polymers with high porosity and high bulk density in the presence of known radical initiators or initiator systems.

Features of the invention

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

GHJSiO / SiB'O / _m / SiEJG./n/2 " ^SiR 2 ^G

SiEO I O

You ¹ OG

n / 2

t / SiB ¹ G /

(III)

m / 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, -öle-, alkoxylate, Cyanalkoxylat- 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 , -OH, -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 concentrations between 0.001 to 0.3% by mass, based on the aqueous phase, and by adding salts or compounds of the metals of the 1st to 3rd main group, alone or in combination, in concentrations of 0.001 to 0.1 Ma, to the polymerization batch. % are added based on the aqueous phase.

As salts or compounds u. a. Sodium chloride, nitrate, sulphate, phosphate, potassium chloride, nitrate, sulphate, phosphate, magnesium chloride, nitrate, sulphate, oxyde, hydroxide, carbonate, fluoride, hydrogen phosphate, pyrophosphate, calcium chloride, nitrate, sulfate, oxide, hydroxide, carbonate, phosphate, hydrogen phosphate, barium chloride, nitrate, sulfate, carbonate, oxide, aluminum chloride and sulfate.

embodiments

Example 1 to 7.

An oxygen-free rinse autoclave was charged with 400 parts of water, 200 parts of vinyl chloride, 0.15 parts of lauryl peroxide, 0.1 parts of dicetyl peroxydicarbonate and 0.05 wt .-% based on the aqueous phase polysiloxane-polyoxyalkylene block copolymers and Table 1 containing amounts to compounds of the 1st to 3rd main group. Polymerization was at

Table 1 connection concentration bulk centrifuge C F Peel at d. connection mass softener around proportion of game Ma. -% bez. a. water g / i admission G - 608 21.8 159 1.52 23.1 1 NaCl 0,025 562 23.3 153 1.76 5.2 2 MgCl ₂ 0,013 587 24.2 195 1.49 6.3 3 Al ₂ (SO ₄ J ₃ 0,007 595 23.6 149 1.75 11.2 4 Ca (H ₂ PO ₄ ), 0,025 588 22.9 174 1.34 7.7 CJ! Mg (OH) ₂ 0,003 564 23.3 163 1.49 9.3 6 NaCl 0,025 543 24.1 164 1.52 4.3 7 Mg (OH) ₂ 0,003

c - mean grain diameter

F - distribution width of gas distribution calculated by:

d - grain diameter

G - Sum weight of the sieve fraction

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 by the suspension process, characterized in that the suspension stabilizers polysiloxane-polyoxyalkylene block copolymers of the general formulas ^ G
or GB'SiO / SiE ¹ O / / SiBJLO / _{/ rt} c- , m 2 vn / 2 , ^ ⁷ n / 2 E ^ SiO / SiE-O / _W3 / SiE "0 / _{n / 2} / SiEO 0 4 0
/ SIB · G / ^ ₃ (III) 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 glycol acetate, oil, alkoxylate, cyano alkoxylate or urea residue of the general formula - / CH ₂ / 3- / OCH ₂ CH ₂ / _p - / OCH ₂ CH (CH ₃ ) / _q -R ' R'-OCOCH ₃ , -OH ^ OCH ₃ , -OCH ₃ , -OC ₄ H ₉ , -OCH ₂ -CH ₂ Cn ₁ -OCONHR "R" alkyl or aryl radical p, q whole or fractional numbers between 4 and 50 in concentrations between 0.001 to 0.3% by weight, based on the aqueous phase, and in that 0.001 to 0.1% by weight, based on the aqueous phase, of salts or compounds of the metals of the 1st to 3rd Main group alone or in combination be added to the polymerization. 2. The method according to item 1, characterized in that as salts or compounds u.a. Sodium chloride, nitrate, sulphate, phosphate, potassium chloride, nitrate, sulphate, phosphate, magnesium chloride, nitrate, sulphate, oxyde, hydroxide, carbonate, fluoride, hydrogen phosphate, pyrophosphate, calcium chloride, nitrate, sulfate, oxide, hydroxide, carbonate, phosphate, hydrogen phosphate, barium chloride, nitrate, sulfate, carbonate, oxide, aluminum chloride and sulfate.