DD256135A1 - METHOD FOR POLYMERIZING VINYL CHLORIDE - Google Patents

Abstract

The invention relates to a process for the polymerization of vinyl chloride in the absence of such amounts of other radically polymerizable monomers necessary for the formation of copolymers, in aqueous and using known initiators or initiator systems, by in a polymerization preceding the polymerization in the presence of 0.001 to 0.2 wt .-% based on the aqueous phase of water-soluble or partially water-soluble known radically polymerizable monomers or mixtures thereof and in the presence of 0.001 to 0.3 Ma .-% based on the aqueous phase, polysiloxane-polyoxyalkylene block copolymers begun is, wherein the polymerization is controlled in a known manner so that upon reaching the predetermined polymerization temperature, which are largely homopolymerized in addition to the monomers to be polymerized vinyl chloride.

Description

Field of application of the invention

The invention relates to a process for the polymerization of vinyl chloride in the absence of such amounts of other polymerizable monomers, which are necessary for the formation of copolymers, and in the presence of polysiloxane-polyoxyalkylene block copolymers in the aqueous phase and using known initiators or initiator systems, wherein homopolymers with a high bulk density and good porosity can be obtained.

Characteristic of the known technical solution

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 deterioration of the other occurs.

As dispersing agents, i.a. Cellulose ethers, as described in DE-OS 2412014, are used. Furthermore, cellulose ethers in a mixture with partially hydrolyzed polyvinyl acetate (DD-PS 145 539) 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 the addition of ionic or nonionic surfactants, often combined with other additives, such as reducing agent to the polymerization to increase the plasticizer receptivity (DE-OS 2 365134,2151703,2244905, DE-PS 1 545179, DE-OS 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 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 is often a deterioration of other product properties, such as. 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 using known initiators or initiator systems with reduced effort.

Explanation of the essence of the invention

The technical task is solved by the invention

The invention is based on the object, a process for the suspension polymerization of vinyl chloride (VC) in the aqueous phase using known, radical-forming initiators or initiator systems, in the absence of such amounts of other known radically polymerizable monomers necessary for the formation of copolymers, and in Presence of polysiloxane-Polyoxyalkyleri block copolymers, which allows to produce VC homopolymers with high bulk density and good porosity.

Features of the invention

The object is achieved according to the invention by polymerization in a polymerization upstream section in the presence of 0.001 to 2.0 wt .-% based on the aqueous phase, water-soluble or partially water-soluble known radically polymerizable monomers, or mixtures thereof, and in the presence of 0.001-0.3Ma .-% based on the aqueous phase, polysiloxane-polyoxyalkylene block copolymers, the polymerization is started, wherein the polymerization is controlled in a known manner so that with the achievement of the predetermined Polymerisationstemperatür, in addition to the VC to be polymerized Monomers largely homopolymerized. , -

As monomers or mixtures thereof z. Acrylic compounds such as acrylic acid, acrylamide, methyl, ethyl, n-butyl, ethylhexyl acrylate, glycol monoacrylate, methacrylic acid, methyl methacrylate, maleic anhydride, maleates, fumarates, vinyl monomers from vinyl esters, vinyl acetate, vinyl ethers, vinyl isobutyl ethers and vinyl aromatics how styren are used. '"

-3- ZOO ΙύΌ

As polysiloxane-polyoxyalkylene block copolymers, those of the general formulas:

RJSiO / "SiR'0_7 _m /" SiR ^ 0_7 _n SiRJ G

GR ₂ SiO /

Rt c; -i Π / CT-iP'ri II Q-ΐΉ'Γΐ II <3 · ίΡ'Γ> / <! · Ϊ́Τ? '

ADLU {_ DJJLt ^ _- / Jj, / ο /. DlXiAU ^ / ν -, / Oi. '- ^> -' - ' ^{: t} -'τπ / 3 ¹ ~ ^{> -i} - ^{i: i} -3

O '~ Wn / 2

O (III)

SiRJ. /

in which mean:

R 'is the same or different lower, optionally substituted, alkyl, preferably methyl, group or integers between 1 and 12, preferably between 2 and η are integers or fractions between 30 and 250, preferably between 40 and G polyoxyalkylene glycol acetate, oils, alkoxylate, cyanoalkoxylate or urea radical of the general formula - [CH ₂ J ₃ - [OCH ₂ CH ₂ ] P- [OCH ₂ CH (CH ₃ ) Iq-R 'R' -OCOCH ₃ , -OH , -OCH ₃ , -OC ₄ H ₉ , -OCH ₂ -CH ₂ CN, -OCONHR "R" alkyl or aryl radical

p, q integers or broken numbers between 40 and used.

embodiments

Examples 1 to 3. ·

An oxygen-free rinse autoclave is charged with 400 parts of water, 200 parts of VC, 0.002 part of isopropanol, 0.1 part of potassium persulfate, 0.7 part of sodium disulfite, 10 " ⁶ parts of copper sulfate, 0.04 part of lauroyl peroxide, 0.03 part of dicetyl peroxydicarbonate and according to the table 1 added amounts of other monomers and polysiloxane-polyoxyalkylene block copolymers (PPB).

Table 1 Monomeric% by mass. on water PPB Ma .-% bez. on water Bulk weight g / i Centrifuge softener intake average grain diameter Distribution range F In game

1 0,125 - 420 33.2 162 2.1 2 0,125 0,006 510 31.6 155 2.3 3 0,125 0.0125 565 29.7 145 2.2

Claims (3)

Invention claim: 1. A process for the polymerization of vinyl chloride in the absence of such amounts of other radically polymerizable monomers which are necessary for the formation of copolymers, in the aqueous phase and using known initiators or initiator systems, characterized in that in an actual polymerization upstream polymerization in the presence from 0.001 to 0.2% by weight, based on the aqueous phase, of water-soluble or partially water-soluble known free-radically polymerizable monomers or mixtures thereof and in the presence of from 0.001 to 0.3% by weight, based on the aqueous phase, of polysiloxane-polyoxyalkylene -Blockcopolymerisaten is started, wherein the polymerization is controlled in a known manner so that upon reaching the predetermined polymerization temperature, which are largely homopolymerized in addition to the monomers to be polymerized vinyl chloride. 2. A process for the polymerization of vinyl chloride according to item 1, characterized in that as monomers or mixtures thereof, acrylic compounds such as acrylic acid, acrylamide, methyl, ethyl, n-butyl acrylate, ethylhexyl acrylate, glycol monoacrylate, methacrylic acid, methyl methacrylate, maleic anhydride, maleinates , Fumarates, vinyl monomers, such as vinyl acetate, vinyl ethers, such as vinyl isobutyl ether and vinyl aromatic, such as styrene. 3. A process for the polymerization of vinyl chloride according to item 1, characterized in that as polysiloxane-polyoxyalkylene block copolymers according to the general formulas: R ₃ SiO SiR ₃ GR ₂ SiO / ~ SiR'0_7 _m / -SiR ₂ 0_7 _{n / 2} - SiR ₂ 0 R ₃ SiO / "SiR Ό J ' Z ^- SiRJO J _n / 2 ^/ - ~ ^Sm '° - ⁷ m / 3 ^SiR 3 in which mean: R 'identical or different lower, optionally substituted alkyl radicals, preferably methyl group m whole or fractional numbers 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-, -alkoxylat-, -cyanalkoxylat- or -ureat -Rest of 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 40 and 50 ι be used.