DD247456A1

DD247456A1 - PREPARATION OF WAITRESS SOLUTIONS CARBOXYL AND HYDROXYL GROUPS-CONTAINING COPOLYMER

Info

Publication number: DD247456A1
Application number: DD28867086A
Authority: DD
Inventors: Harald Friedrich; Juergen Rudorf; Volker Steinert; Dieter Schermaul; Manfred Raetzsch; Matthias Boettger; Hans-Jochen Goetz; Guenter Otte
Original assignee: Leuna Werke Veb
Priority date: 1986-04-02
Filing date: 1986-04-02
Publication date: 1987-07-08

Abstract

Verfahren zur Herstellung waessriger Loesungen carboxyl- und hydroxylgruppenenthaltender Copolymerer. Als Modifiziermedium wird Wasser verwendet, in dem Ethanol- oder Diethanolamin geloest werden. Bei 283 bis 298 K wird ein Propen-, alpha-Methylstyren- oder Ethen-Maleinsaeureanhydrid-Copolymer unter Ruehren zugegeben. Die entstandene Polymerdispersion aus modifiziertem Copolymer und Wasser wird mit maximal 20 K pro Stunde erhitzt bis eine klare Loesung entstanden ist. Der Modifizierungsgrad wird durch Variation des Molverhaeltnisses Amin zu Saeureanhydridgruppen eingestellt. Die erfindungsgemaess hergestellten Loesungen eignen sich zur Verhinderung von Wandablagerungen in Kuehlwassersystemen.Process for the preparation of aqueous solutions of copolymers containing carboxyl and hydroxyl groups. The modifying medium used is water in which ethanol or diethanolamine is dissolved. At 283 to 298 K, a propene, alpha-methylstyrene or ethene-maleic anhydride copolymer is added with stirring. The resulting polymer dispersion of modified copolymer and water is heated at a maximum of 20 K per hour until a clear solution is obtained. The degree of modification is adjusted by varying the molar ratio of amine to acid anhydride groups. The inventively prepared solutions are suitable for preventing wall deposits in Kuehlwassersystemen.

Description

Die im Anschluß an den Modifizierungsschritt vorliegende Polymerdispersion wird unter weiterem Rühren langsam erwärmt, wobei maximal 2OK pro Stunde aufgeheizt wird. Beim Erreichen von 313 bis 323K entsteht eine klare gebrauchsfähige Lösung, die mit Wasser in jedem Verhältnis mischbar ist.The polymer dispersion present after the modification step is heated slowly with further stirring, heating a maximum of 2OK per hour. When reaching 313 to 323K, a clear, workable solution is formed which is miscible with water in any ratio.

Die erfindungsgemäß hergestellten Lösungen lassen sich vorteilhaft in Kühlwassersystemen einsetzen, wo sie bewirken, daß Wandbeläge in Kühlern, die die Rohre zusetzen und den Wärmeübergang behindern, weitestgehend vermieden werden.The solutions according to the invention can be used advantageously in cooling water systems, where they cause wall coverings in coolers, which clog the pipes and hinder the heat transfer, are largely avoided.

Ausführungsbeispieleembodiments

example 1

In einem 41-Rührgefäß werden bei 283K in 1407g Wasser 427g Ethanolamin gelöst. 980g Propen-Maleinsäureanhydrid-Copolymer werden dieser Mischung unter Rühren in einer solchen Geschwindigkeit zugesetzt, wobei das Rührgefäß temperiert wird, daß 283 K nicht überschritten werden. Anschließend wird die wäßrige Polymerdispersion mit einer Geschwindigkeit von 20 K pro Stunde erhitzt. Nach 2 Stunden liegt eine klare 50 Ma.-% Feststoff enthaltende wäßrige Lösung des modifizierten Copolymeren vor. Die Säurezahl des isolierten 100%ig amidierten Produktes beträgt 284mg KOH pro Gramm Copolymer.427 g of ethanolamine are dissolved in 1407 g of water in a 41 stirred vessel at 283K. 980 g of propene-maleic anhydride copolymer are added to this mixture with stirring at such a rate, wherein the stirring vessel is heated to 283 K are not exceeded. Subsequently, the aqueous polymer dispersion is heated at a rate of 20 K per hour. After 2 hours, there is a clear 50 wt .-% solids aqueous solution of the modified copolymer. The acid number of the isolated 100% amidated product is 284 mg KOH per gram of copolymer.

Example 2

In einem temperierbaren 6I-Rührgefäß werden 3593g Wasser und 420g Diethanolamin gemischt. Bei 293K werden 1120g Propen-Maleinsäureanhydrid-Copolymer unter Rühren mit einer solchen Geschwindigkeit zu dieser Mischung gegeben, daß 293 K nicht überschritten werden. Nach Erwärmen dieser Polymerdispersion mit einer Geschwindigkeit von 15K pro Stunde wird nach 2,5 Stunden eine klare 30 Ma.-% Feststoff enthaltende Lösung erhalten. Das isolierte Produkt mit einem Amidierungsgrad von 50% hat eine Säurezahi von 441 mg KOH pro Gramm Copolymer.In a temperature-controlled 6I stirred vessel, 3593 g of water and 420 g of diethanolamine are mixed. At 293K, 1120 g of propene-maleic anhydride copolymer are added to this mixture with stirring at such a rate that 293K is not exceeded. After heating this polymer dispersion at a rate of 15K per hour, a clear solution containing 30% by mass solids is obtained after 2.5 hours. The isolated product having a degree of amidation of 50% has an acid number of 441 mg KOH per gram of copolymer.

Example 3

In einem 31-Rührgefäßwerden bei 283K 1 993g Wasserund 12,21 Ethanolamin gemischt. 216g alpha-Methylstyren-Maleinsäureanhydrid-Copolymerwerden unter Rühren dieser Mischung bei 283 K zugesetzt. Anschließend wird die entstandene Dispersion nach Zugabe von 15,3g Ammoniak in Form von 25%igem Ammoniakwasser mit einer Geschwindigkeit von 10K pro Stunde erhitzt.In a 31-pot, 1,993 g of water and 12.21 of ethanolamine are mixed at 283K. 216 g of alpha-methylstyrene-maleic anhydride copolymer are added while stirring this mixture at 283K. Subsequently, the resulting dispersion is heated after addition of 15.3 g of ammonia in the form of 25% ammonia water at a rate of 10K per hour.

Nach 6 Stunden wird eine klare 10Ma.-% Feststoff enthaltende Lösung erhalten. Das isolierte Produkt mit einem Amidierungsgrad von 20% hat eine Säurezahl von 452mg KOH pro Gramm Copolymer.After 6 hours, a clear 10Ma .-% solid solution is obtained. The isolated product with a degree of amidation of 20% has an acid number of 452 mg KOH per gram of copolymer.

Example 4

In einem 41-Rührgefäß werden bei 283 K 1122g Wasserund 366 g Ethanolamin gemischt.In a 41 stirred vessel, 1122 g of water and 366 g of ethanolamine are mixed at 283K.

756g Ethen-Maleinsäureanhydrid-Copolymer werden unter Rühren dieser Mischung in einer solchen Geschwindigkeit zugesetzt, daß 283 K nicht überschritten werden. Anschließend wird die wäßrige Polymerdispersion mit einer Geschwindigkeit von 20 K pro Stunde erhitzt. Nach 1,5 Stunden liegt eine klare 50 Ma.-% Feststoff enthaltende wäßrige Lösung des modifizierten Copolymeren vor. Die Säurezahl des isolierten 100%ig amidierten Produktes beträgt 302mg KOH pro Gramm Copolymer.756 g of ethylene-maleic anhydride copolymer are added with stirring to this mixture at such a rate that 283 K are not exceeded. Subsequently, the aqueous polymer dispersion is heated at a rate of 20 K per hour. After 1.5 hours, a clear 50 wt .-% solid aqueous solution of the modified copolymer is present. The acid number of the isolated 100% amidated product is 302 mg KOH per gram of copolymer.

Claims

Invention claim:

1. A process for the preparation of aqueous solutions of carboxyl- and hydroxyl-containing copolymers by modifying alternately structured low molecular weight propene-maleic anhydride, alpha-methylstyrene, maleic anhydride or ethene-maleic anhydride copolymers with ethanolamine or diethanolamine, characterized in that a solution of ethanolamine or Diethanolamine in water, the maleic anhydride copolymer having a weight average molecular weight of 500 to 50,000 is added and a reaction temperature of 283 to 298K is maintained, the molar ratio of amine to acid anhydride groups in the copolymer <1 and after completion of the copolymer addition, the reaction dispersion with a maximum of 20 K / H is heated until a clear solution is formed.

.2. Process according to item 1, characterized in that maleic anhydride copolymers are used which have a weight average molecular weight of 500 to 10,000.

Field of application of the invention

The invention relates to a process for the preparation of aqueous solutions of copolymers containing carboxyl and hydroxyl groups based on alternating low molecular weight and with ethanolamine or diethanolamine modified propene-maleic anhydride copolymers, alpha-methylstyrene-maleic anhydride copolymers or ethylene-maleic anhydride Copolymeren.

Characteristic of the known technical solutions

The preparation of ethanolamine and diethanolamine-modified styrene-maleic anhydride copolymers and their use as film formers on concrete is described in SU-PS 1073240. The copolymer is dissolved in dioxane and this solution is added to a mixture of water and amine. Certain ratios of the amounts of dioxane to water and amine to copolymer must be observed. After the reaction, an excess of water is added to this reaction mixture and the modified copolymer is precipitated by acidification to a pH of 5. After washing the copolymer with water to remove the acid, the modified copolymer is dried to finally be redissolved in water or aqueous bases.

A disadvantage is the complicated process for the preparation of aqueous solutions. First, the reactants have to be dissolved in two different media and the reaction has to be started by mixing these solutions. After dilution with large amounts of water and precipitation with acid, the copolymer is recovered, then washed and dried to finally dissolve in water. The workup of the dioxane-water mixture is complicated and economically ineffective. That is worked in any case with an excess of amine and only at a large excess of amine 100% amidated products are obtained, represents a further significant disadvantage of the method.

Object of the invention

The aim of the invention is the preparation of concentrated aqueous solutions of copolymers containing carboxyl and hydroxyl groups based on alternating low-molecular and with ethanolamine or diethanolamine-modified propene-maleic anhydride copolymers, alpha-methylstyrene-maleic anhydride copolymers or ethylene-maleic anhydride copolymers in economically and technologically effective way.

Explanation of the essence of the invention

The invention is based on the object, a low molecular weight alternating propene-maleic anhydride copolymer, alpha-methylstyrene-maleic anhydride Copqlymer or ethylene-maleic anhydride copolymer in a reaction medium which is immiscible with water indefinitely, non-corrosive, toxic or flammable, with ethanolamine or To modify diethanolamine and then dissolve the modified copolymer in the same reaction media, if necessary with heating.

The object is achieved in that according to the invention the maleic anhydride copolymer is stirred at 283 to 298 K in a mixture of water and ethanolamine or diethanolamine. The amine is used in amounts of <1 mole per mole of anhydride groups in the copolymer. The amount of water is such that the weight ratio of water to modified copolymers is 1: 1 to 9: 1. Propene-maleic anhydride, alpha-methylstyrene-maleic anhydride or ethene-maleic anhydride copolymers having weight-average molar masses of 500 to 50,000, preferably 500 to 10,000, are used. Surprisingly, water is suitable as a modifying medium if, according to the invention, the ethanolamine or diethanolamine is dissolved in water prior to the addition of the copolymers and the addition of the copolymer is made such that the reaction temperature is between 283 and 298 K. By a controlled addition of the copolymer, the released heat of reaction is controlled so that it can be removed by the tempering of the reactor.

Under these conditions, unexpectedly, only the amidation reaction proceeds quantitatively, and the hydrolysis of maleic anhydride groups or the crosslinking reaction by reaction of the alcoholic groups of the ethanolamine or diethanolamine with maleic anhydride groups does not occur. The degree of amidation can be easily and advantageously adjusted on the basis of this finding by controlling the molar ratios of ethanolamine and diethanolamine to maleic anhydride groups.