DD263779A1 - PROCESS FOR PREPARING HOMO OR COPOLYMERISATES OF VINYL CHLORIDE - Google Patents

Abstract

The invention relates to a process for the preparation of homopolymers or copolymers of vinyl chloride by the suspension and microsuspension process using known macromolecular dispersants or combinations in amounts of from 0.01 to 0.2% by weight and / or known emulsifiers or combinations in quantities of 0.2 to 3% by weight in each case a. Monomer with initiator contents that allow a uniform reaction to obtain polymers with improved, homogeneous application properties. The process is carried out by mixing the monomers prior to dispersion with water, the known initiator or the known initiator combinations as an aqueous dispersion or as a solution in an inert organic solvent through a nozzle with Reynolds numbers> 5000 uniformly throughout the monomer stream leading into the reactor are metered in that before mixing with water residence times of the initiator-monomer mixture of> 10 seconds are set.

Description

Characteristic of the known technical solutions

In the known processes of suspension and microsuspension polymerization of vinyl chloride, it is customary to introduce the initiator in batch form with all other starting materials and then to carry out the known reactions (Houbsn-Weyl "macromolecular substances"), the problem being the uniform distribution of the initiator Only very incomplete to solve and there are particles with seh ·· different product properties, so ts has not been lacking of attempts to homogeneously Monomero · with the initiator · zu. It is known to dissolve the initiator in a solvent, this on a The desired quality of corresponding droplet size can be divided in the water and then the monomer can be brought into the solvent droplets by diffusion (DOS 2737112) A disadvantage is the relatively large amount of solvent which negatively influences the course of the reaction and the complicated time-dependent monomer diffusion.

Furthermore, processes are known for which the Rntch batch is stirred vigorously for a relatively long time before the start of the polymerization, in order to effect the mass transfer between the monomer droplets for the same distribution (J. Kokai 79163983). In addition to the economically unjustifiable loss of time, depending on the substance system, the replacement of the initiators is limited and not complete, in particular emulsifier and dispersant protective layers block the mass transfer between monomer droplets.

It is also known either to introduce the entire initiator in a small amount of monomer and to charge the remaining monomer onto the polymerizing particles (D-OS 2427953) or to polymerize the monomer which is not completely reactive by subsequently added initiators (D-OS 2039010). In both cases, it is disadvantageous that the diffusion-related process is substance-dependent, run through the blocking adjuvants side reactions in the aqueous phase and thus no homogeneous product of suspension or micrc-usperisionspolymerisaten arises.

The use of the technologically and safety-nuthandierbaren initiator dispersions for suspension and Macrosuspensionspolymerisationen is known in batch approaches (D-OS 2 634131), but complicates the initiator transition into the monomer and therefore does not solve the problems of homogeneous distribution.

There are also known the use of initiator locks in which the entire initiator is introduced and the monomer is passed through. However, it is not possible to dissolve over the entire monomer current a constant amount of initiator, so that there is still the problem of uneven distribution.

There is no method known from the prior art, which distributes the initiators so economically and technologically oinfache manner in the monomer that a uniform reaction in all drops at homogeneous product properties.

Object of the invention

The object of the invention is the preparation of monomer-water mixtures with initiator contents which allow a uniform reaction to obtain polymers with improved technical properties.

Explanation of the essence of the invention

The technical problem solved by the invention.

The invention has for its object to develop a process for the preparation of homo- or copolymers of vinyl chloride using conventional technical equipment, in which by the distribution of the initiator in Monomerei ι a uniform reaction and a polymer with narrower molecular and particle size distribution arise.

Features of the invention

The object is achieved according to the invention by dispersing the monomers with the known initiator or the known initiator combinations as aqueous dispersion or as solution in an inert organic solvent via a nozzle with Reynolds numbers> 5000 gle .- The monomer stream leading to the reactor can be metered in so that, before mixing with water, residence times of the monomer / monomer mixture of> 10 seconds are set.

Ausführiingsbelspiele

Comparative Example (Example 1)

120 parts of water, 1.5 parts of alkylsulfonate, 0.1 part of dilauroyl peroxide and 0.03 parts of dicetyl peroxidicarbondt are placed in a 100 liter pressure vessel with impeller stirrer and baffle. After purging with nitrogen, 100 parts of VC are metered in and stirred at 110 rpm for 30 minutes. Subsequently, the mixture is fed to a Manton-Gaulin homogenizer and driven through pressure stages of 1.5 and 0.3 MPa in a Pm kettle with Kreuzbalrichrührer, polymerized at 52 ⁰ C with a gel phase temperature increase to 7O ⁰ C and after 10 hours relaxes the remaining monomer. The latex is worked through spray drying at 55 ⁰ C foot temperature. The product is characterized by the following characteristics:

M _w : M _n 2.8

Particle size distribution of 60 to 2 200 nm

Paste PVC: DOP = 3: 2 with a viscosity of D = 48.6s ~ 'from 3300mPas

Example 2

Analogously to Example 1, the 100 liter pressure vessel is charged with 120 parts of water and 1.5 parts of alkyl sulfonate. After purging with nitrogen, the VC metering pump at 50 l / h and the initiator metering pump at 120 ml / h are switched on at the same time. A 40% strength initiator dispersion consisting of 0.01 part of dilauroyl peroxide and 0.03 part of dicetyl peroxydicarbonate dispersed with cellulose ether in water is used, which is sprayed into the monomer stream via a capillary nozzle with nozzle insert immediately after the VC metering pump, which after 100 Parts is turned off. The entire batch mixture is then dispersed and homogenized as in Example 1, polymerized at 52 ⁰ C, relaxed after 8 hours at a gel phase temperature increase to 62 ⁰ C and spray-dried. The product is characterized by the following characteristics:

M _w : M _n 2,3

Particle size distribution from 80 to 2000 nm

Paste PVC: DOP = 3: 2 with D = 48.6s ~ 'with a viscosity of 2500mPas

Example 3

The procedure is analogous to Example 2, except that instead of the initiator dispersion, a 10% solution of both initiators to proportions similar to Example 2 in xylene is used, which is sprayed with a Dosierpumpeneinstellung of 500 mI / h in the monomer stream. The polymerization is complete after 8 hours with a gel phase temperature increase to 58 ⁰ C. The product prepared analogously to Example 2 has the following characteristics:

M _w : M _n 2,2

Particle size distribution 100 to 1,800 nm

PastePVC: DOP - 3: 2 at D = 48.6s ~ 'with a viscosity of 2200mPas

Comparative Example (Example 4)

180 parts of water, 0.1 part of propoxymethylcellulose and 0.06 part of dilauroyl peroxide and 0.015 part of diisopropyl peroxydicarbonate are placed in a 100 liter pressure vessel with impeller stirrer and baffle. After purging with nitrogen, 100 parts of VC are metered in and polymerized at 110 rpm and 55 ° C. After 6 hours at a Gelphasentemperaturhöherig to 7O ⁰ C is there? removed residual monomers, the dispersion was dewatered via decanters and the product was dried in a fluidized bed. It is characterized by the following characteristic values:

M _w : M _n 2.6

Grain fraction <63 pm 12% plasticizer & uptake

(Centrifuge method) 25%

Example 5

In a 100 liter pressure vessel analogous to Example 4, 180 parts of water and 0.1 parts of propoxymethylcellulose are presented. After purging with nitrogen, the VC metering pump with 50 l / h and the initiator metering pump with 500 ml / h are switched on at the same time. A 10% strength solution of the proportionate amounts of initiator analogous to Example 4 is used, which is sprayed into the monomer stream via a nozzle directly behind the VC metering pump. After the addition of 100 parts of VC, the dosage is turned off, the entire Ansa'zgemisch polymerized at 110Up, n and 5o ° C for 5 hours, with a Gelphasentemperaturorhöhung to 6O ⁰ C occurs. Subsequently, the product is worked up analogously to Example 4 and is characterized by the following characteristics:

M _w : M _n 2,2

Grain fraction </ im 2%

plasticizer absorption

(Centrifuge method) 15%

Claims (1)

Process for the preparation of homopolymers or copolymers !! of the vinyl chloride by the suspension and microsuspension method using known ·· macromolecular dispersants or combinations in amounts of from 0.01 to 0.2% by weight and / or known emulsifiers or combinations in amounts of from 0.2 to 3% by mass each bez. a. Monomer, characterized in that the monomer prior to dispersion with water, the known initiator or the known initiator combinations as an aqueous dispersion or as a solution in an inert organic solvent through a nozzle with Reynolds numbers> 5000 uniformly the entire monomer stream leading into the reactor so are added, that are set before mixing with water residence times of the initiator monomer mixture of> 10 seconds. Field of application of the invention The invention relates to a process for the preparation of homo- or Copolymerisaien of vinyl chloride by the Suspsnsions- and microsuspension process using known macromolecular dispersants or combinations in amounts of 0.01 to 0.2Ma .-% and / or known emulsifiers or combinations in Amounts of 0.2 to 3% by weight in each case a. Monomer.