DD290901A5 - PROCESS FOR PREPARING WATER-SOLUBLE HIGH-TWIN CATIONIC COPOLYMER POWDER - Google Patents

Abstract

The invention relates to the preparation of water-soluble highly branched cationic copolymer powder, which can be used for wastewater treatment and for the demulsification of OEl / water emulsions. According to the invention, water-soluble hyperbranched cationic copoly-pyrrolidinium salt solutions which can be obtained by copolymerization of dimethyldiallyl-ammonium chloride with methyl-triallyl-ammonium chloride, tetraallyl-ammonium chloride or methylene-bis-acrylamide are stirred and heated in a heatable stirred kettle equipped with a wall-mounted stirrer and flow breaker treated until the water content of the copolymer has dropped to less than 25%. Such copolymer powders can be dissolved in a very short time with water. {Copolymer powder; water soluble hyperbranched cationic copolymer powders; Copoly-pyrrolidinium; Dimethyl diallyl ammonium chloride; Copoly-dimethyl-diallyl-ammonium chloride; Tertraallylammoniumchlorid; Triallyl-methyl ammonium chloride}

Description

Field of application of the invention

The invention relates to a process for the preparation of water-soluble hochverzv. Cationic copolymer powders from aqueous solutions of highly branched cationic copolymers of dimethyl diallyl ammonium chloride. Water soluble highly branched cationic copolymer powders can find a variety of industrial uses; For example, for separation processes in the field of wastewater treatment and for the demulsification of oil / water emulsions.

Characteristic of the known state of the art

Water-soluble hyperbranched high molecular weight quaternary copolypyrrolidinium salts have previously been prepared by free radical initiated solution polymerization of dimethyldiallylammonium salts with suitable crosslinker components such as alkyltriallylammonium salts, tetraallylammonium salts or alkylene-bis-acrylamides in water, the crosslinking comonomer was added only in the course of the already ongoing polymerization of dimethyl diallyl ammonium salt after conversions of at least 25%. Such solutions, even at a level of 20%, have a significant viscosity which necessitates the use of special transport and metering pumps or further dilution to less than 10% solids. In order to use conventional pumps, the disadvantage of high dilution must be accepted.

To avoid this disadvantage has already been proposed to use powdery products. Bisner used powdered products in turn had the disadvantage of low solubility or low dissolution rate and therefore required the use of special solvent stations (J. Eisenbauer, D. Dorn "Flocculation Chemicals", DVGW Water Series No. 42, p. 85, Eschhorn 1985)

 There has hitherto been no technology proposed which avoids these deficiencies.

Object of the invention

It is the object of the invention to obtain water-soluble highly branched cationic copoly-pyrrolidinium salts, which are obtained immediately after completion of the radical copolymerization, from their concentrated solutions in a powdery, free-flowing form

 The powders should have a high dissolution rate with good solubility.

Explanation of the nature of the invention The invention is based on the object, of course, the film-forming copoly-pyrrolidinium without drying

to transfer energy-intensive grinding processes in powder form.

According to the invention, water-soluble highly branched cationic copolymer powders from aqueous solutions Concentrate and Evaporation obtained when in an appropriately designed open stirred tank with

heated stirrer and built-in flow breakers with constant stirring and heating until the

Water content of the copolymer has dropped to less than 25%. The drying and pulverization time of Copolymer solution depends on the batch size, the desired degree of drying and the heat energy supplied

and is usually 3 to 5 hours.

The formation of loose polymer powders under the conditions of the invention was surprising, among others Conditions (without stirring) only hard, compact polymer scars are obtained, which subsequently no longer

let it pulverize.

The polymer powders which can be prepared according to the invention are yellowish free-flowing products which, when stirred into water in

soluble in a short time and therefore easy to process.

The following examples are intended to further explain the process according to the invention and the use of the products

demonstrate.

embodiments

The process according to the invention described in the examples is carried out in a commercial open stirred kettle which is equipped as follows:

- The usual anchor agitator is changed at a distance to Kesselwanduno ^so that the boiler wall remains a minimum gap width;

- In addition to the vertical stirrer axis, two stunner breakers are additionally installed (tube with star-shaped shingles);

- There is a removable cover of the stirred tank and a suction device installed.

example 1

Strength 400MoI a 50% aqueous dimethyl-diallyl-arnmoniumchlorid solution (OMDAAC) are heated in the mixer to 4O ⁰ C. With stirring and strong cooling, 2 mol% of ammonium peroxodisulfate and 2 mol% of ammonium carbonate are added. After a total of 1 hour is now within 10 hours, a continuous addition of 1 mol% triethanolamine, the temperature between 18 and 25 ° C is maintained. After a reaction time of 88 hours, 0.5 mol% of methyl triallyl ammonium chloride (MTAAC) in the form of a 50 mol% DMTAAC solution containing 10 mol% MTAAC is added in one portion to the batch. As the reaction progresses, the temperature gradually increases to 35 ^° C. with constant cooling. After 11 hours, the polymerization is complete.

To convert the copolymer obtained in polymer powder, the solution with stirring and heating constantly mi. Saturated steam concentrated, initially a mushy mass is formed, which is stirred with progressive drying to a powder. As a result of the procedure according to invention one receives after 4 hours a powdered cationic copolymer with a Aktivsubstanzgehalt of 70%.

Be! Splol2

The procedure is as described in Example 1, but increases the drying and stirring time to 5 hours. A powder is obtained

75% active ingredient content.

Example 3 The procedure is as in Example 1, but uses as comonomer 1 mol% of tetraallyl-ammonium chloride. The test result

corresponds to that of Example 1.

Example 4

Separation of an oil / water emulsion with water-soluble copoly-pyrrolidinium chloride powder prepared according to Example 1. A used oil emulsion (oil content 5% by volume), which was used as a cooling lubricant in a lathe, was mixed with 100 mg / l copolypyrrolidinium chloride powder and 10 seconds intensely mixed. The mixture was then stirred at 10 rpm for 45 minutes. This was carried out phase separation. Subsequently, the light transmittance of the aqueous phase in a layer thickness of 1 cm was 83 ° and the residual oil content was 36 mg / l.

Example 5

100 ml of a suspension of kaolin in water with 2 g solid / 1 was added at 2O ⁰ C with 1 mg / l of the copoly-pyrrolidinium chloride powder according to Example 1 and stirred for 10 min at 200U / min. After 12 minutes, a constant transparency of the aqueous phase of 87.1% had been established (transparency 0 for the kaolin suspension used).

Claims (2)

A process for the preparation of water-soluble highly branched cationic copolymer powder, characterized in that aqueous solutions of highly branched cationic Copolypyiolidiniumchloriden be treated in a equipped with Wandgängigem stirrer and flow breakers heatable stirred tank under stirring and heating until the Res.wassergehalt of the product has dropped to less than 25% , 2. The method according to claim 1, characterized in that aqueous solutions of Copolypyrr'olidiniumchloriden are used, which are obtained by copolymerization of dimethyl-diallylammonium chloride with methyl-triallyl-ammonium chloride, tetraallyl-ammonium chloride or methylene-bis-acrylamide.