DD240998A3 - 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, which are necessary for the formation of copolymers, in the aqueous phase and using known initiators or initiator systems, by in an actual polymerization upstream polymerization in the presence of 0.001 to 2.0 wt .-%, based on the aqueous phase, water-soluble or partially water-soluble, known, free-radically polymerizable monomer, or mixtures thereof is started, the polymerization is controlled in a known manner so that upon reaching the predetermined polymerization temperature , which are largely homopolymerized in addition to the monomer to be polymerized vinyl chloride. Acrylic compounds such as acrylic acid, acrylamide, methyl, ethyl, n-butyl acrylate, ethylhexyl acrylate, glycol monoacrylate, methacrylic acid, methyl methacrylate, furthermore maleic anhydride, maleinates, fumarates, vinyl monomers from the series of vinyl esters, such as vinyl acetate, can be used as further monomers or mixtures thereof. the vinyl ethers such as vinyl isobutyl ether and vinyl aromatics such as styrene.

Description

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 Copolymerisäten.in aqueous phase and using known initiators or initiatorsystems.wobei homo polymers are obtained with predetermined particle size and porosity.

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. the property of the dispersant system, the distribution of the monomer or monomers in the aqueous phase, the morphology of the PVC grain, in particular its porosity, the particle size distribution, but also the thermal stability of the polymer.

As dispersants u.a. Cellulose ethers, as described in DE-OS

In addition, cellulose ethers in a mixture with partially saponified polyvinyl acetate (DD-PS 145 539) or only polyvinyl acetate (DE-AS 1 142 238) are used.

To achieve high porosities, additional aliphatic or aromatic Kohlenviasserstoffe or alcohols are used (US-PS 2,875,186.

3 488 328).

It is furthermore known that the plasticizer absorption capacity can be increased by adding long-chain fatty acids or esters thereof or by adding ionogenic or non-ionogenic surface-active substances, often combined with other additives, such as reducing agents to the polymerization mixture. (DE-OS "365 134.2 151 703, DE-PS 1 545 179 _, DE-OS 2 244 985 _, 2 143 604) also describes the combination of suspension stabilizers for influencing the plasticizer receptivity. (US Pat. No. 3,879,365 _; DE-AS 1 720 328.DE-OS 2,209,592)

A polyvinyl chloride with a high bulk density _} low porosity and a relatively broad particle size distribution is obtained when using StyrolAialeinsäureanhydrid copolymers as a dispersant. (DD PS 13 583 _: 14 358)

Waxing part of this procedure is it _? that macromolecular compounds must be used as the main component of the dispersant systems used. Their production is possible only through complicated processes ", resulting in that the dispersants thus prepared are subject to strong fluctuations in their properties, which in turn has a negative effect on the product properties. Another aspect is the high cost of producing these dispersants,

Aim of the invention

The aim of the invention is the preparation of vinyl chloride homopolymers of predetermined particle size and porosity using known initiators or initiator systems, with reduced expenditure.

- 3 Presentation of the essence of the invention

- The technical problem which is solved by the invention

The invention has for its object to provide a process for suspension polymerization of vinyl chloride (VC) in the aqueous phase, using known radical-forming initiators or initiator systems and in the absence of such amounts of other known radically polymerizable monomers, which are necessary for the formation of copolymers to develop which makes it possible to produce VC homopolymers of predetermined particle size and porosity.

Features of the invention

The object is achieved according to the invention by starting polymerization in a polymerization section upstream of the actual polymerization in the presence of from 0.001 to 2.0% by weight, based on the aqueous phase, of water-soluble or partially water-soluble known radically polymerizable monomers or mixtures thereof. wherein the polymerization is controlled in a known manner so that upon reaching the predetermined polymerization temperature in addition to the monomers to be polymerized VG monomers are largely 'homopolymerized.

As monomers, or mixtures thereof z. As acrylic compounds such as acrylic acid, acrylamide, methyl-ethyl, n-butyl, ethylhexyl acrylate, glycol monoacrylate, methacrylic acid, methyl methacrylate, further maleic anhydride, maleinates, fumarates, vinyl monomers from the series of vinyl esters such as vinyl acetate, vinyl ethers such as vinyl isobutyl ether and Vinyl aromatics such as styrene are used.

The polymerization is carried out by keeping the temperature of the polymerization batch below the polymerization temperature of the vinyl chloride at the beginning of the polymerization. This temperature is maintained until the added monomers are largely homopolymerized. Thereafter, the temperature is raised to the polymerization temperature of the vinyl chloride, according to the intended level of property and polymerized to completion without

there is a detectable formation of copolymers of added next to the VC monomers. The addition of dispersants is not required.

embodiments

Example 1 to 6

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 parts of copper sulfate,. 0.04 parts of lauroyl peroxide, 0.03 parts of dicetyl peroxydicarbonate and added according to Table 1 amounts of other monomers. Is polymerized with stirring for 1 hour at 318 K and 5 hours at 336 K.

Example 7 to 10

Charged and polymerized according to Example 1 to 6, are added 0.38% by weight of acrylic acid and 0.25% by mass based on the aqueous phase of another monomeric compound according to Table 2.

Example 11 to 13

It is charged and polymerized according to Example 1 to 6, are added 0.25% by mass of acrylic acid and 0.25% by mass based on the aqueous phase, another monomer according to Table 3.

Example 14 to 17

The procedure is as in Example 1 to 6 carried out, are added another monomer and an auxiliary dispersant according to Table 4.

table

Example of monomer No. next to VC

Dimensions %

based on the Wassr.Phase centrifuge bulk density of medium distribution plasticizer. Grain diameter width P

c % (g / l)] Jm

Acrylamide 0.58

Acrylamide 1.00

Acrylic acid 0.25

Acrylic acid 1.00

Vinyl acetate 0.38

34.7 410 170 1 _; 84 119.0 217 195 2.70 80 290 20   - 49 220 165 2.5 48 446 260 3> 7 70.5 265 146 2.8

C - mean grain diameter of the Gaussian distribution

F- distribution width of the Gaussian distribution

G F = -

d - grain diameter

G - Sum weight of the sieve fraction

^l 95

Tables 2 and 3

example monomeric centrifuge Schüttge medium grain distribution No. softly on η < weight diameter wide C % g / l around 7 acrylic acid 48.2 305 160 4 5 8th Methylmeth- acrylate 51 1 245 180 2., 1 9 methyl acrylate 44.6 275 240 1-94 10 vinyl acetate 65.6 275 320 1.81 11 methyl acrylate 14 4 600 360 3 9 12 Methylmeth- acrylate 19.9 490 135 3 0 13 butyl acrylate 5.6 630 580 7.1

Table 4

Example of monomer No.

Hilfsdispergator

Zentifugen- Schutt- middle

Plasticizer weight grain diameter

recording knife

% μη

Distribution width c

14 0.38 mass % 0 _: 2 parts Pett- 114 290 190 4.2 acrylamide säureglycerin- ester 31.7 402 146 2; 6 15 0.38 mass % 0.09 parts Sorbi acrylamide tanmonolaurat 15.8 640 450 2 8 16 0 _; , 25 mass% 0.2 parts fat acrylic acid acid egly cerine st 23.3 4450 260 2 6 17 0.25 mass% 0.09 parts Sorbi acrylic acid tanmonolaurat

Claims (2)

invention claims 1.The process for the polymerization of vinyl chloride in the absence of such amounts of other radically polymerizable monomers. in the aqueous phase and using known initiators or initiator systems., characterized in that in one of the actual polymerization upstream polymerization in the presence of 0.001 to 2 0 % by weight based on the aqueous phase, water-soluble or The polymerization is controlled in a known manner so that upon reaching the given polymerization temperature, the monomers added in addition to the vinyl chloride to be polymerized are substantially homopolymerized. 2.Verfahren for the polymerization of vinyl chloride according to item 1, characterized in that as' monomers bzw.deren mixtures of acrylic compounds, such as acrylic acid.acrylamide _; Methyl _; Ethyl-.n-butyl acrylate.Ethylhexyl acrylate-crlycol monoacrylate Methacrylic acid, methyl methacrylate _: furthermore maleic anhydride J'alalates, fumarates, vinyl monomers from the series of vinyl esters such as, vinyl acetate of vinyl ethers such as vinyl isobutyl ether and vinyl aromatics such as _; Styren.used to be.