DD144415A1 - PROCESS FOR AGGLOMERATING BUTADIEN COPOLYMERISATLATICES - Google Patents

Abstract

The invention relates to a method for agglomerating Butadiene Copolymerisatlatices as a prerequisite for a concentration to latexes with more than 60% solids content. As Agglomeriermittel be 0.01 to 0.5% of a mixture used from a) at least one nonionic emulsifier with an HLB value of 10 to 17 and b) one Emulsion copolymer of vinyl aromatics, dienes, unsaturated Carboxylic acids and 2 to 40% esters of unsaturated carboxylic acids, preferably Esterification products of the Diels-Alder adducts of maleic acid, wherein the esters are saponified to 0.1 to 20%. It is dss Ratio of a) to b) 1 to 4 to 4 to 1. Then will be up to 0.2% Na or K silicofluoride is added, and the latex becomes set under pressure of 250 to 500 kg / cm2 and then relaxed. According to the invention, premature coagulation of the Latex and also a strong increase in viscosity avoided. The limits of latex composition and Agglomerating agents are considerably expanded,

Description

13741

Ti t e 1 .d e_r_Er fi_n d mi g

Process for agglomerating butadiene copolymer latices

Field of application of the invention

The invention relates to a process for the agglomeration of butadiene Copolyiaerisatlatices as a prerequisite for the concentration of these latices _o latices with a pesticide content above 60 % are suitable, inter alia, for the production of foams.

Characteristic of the known tea mixes solutions

Chemical agglomeration of latices is well known. Agglomerating agents are added to the latices, which can be divided into two classes: 1 · strong and spontaneously acting agglomerating agents such as. B, carboxylic acids, salts of polyvalent metals, organic salts, and 2, weakly and gradually or on heating acting agglomerating agents such. B. Ammonium salts, zinc oxide, sodium and Kalitimsilikofluorid, mercaptobenzothiazole and its zinc salt, polyformals, mercaptobenzimidazole and its zinc salt, polyvinyl methyl ether, polyoxypropylene glycol and certain functional siloxanes fKAUTSCHUK AND RUBBER, KUINSTSTOFFE 27th vintage Ur. 9/197 ^ · page 369).

The use of such additives to agglomerate latices is very critical, as premature coagulation of the latex often occurs. Despite the same physical characteristics apparently same latices react again at different speeds on the same amounts of the same agglomerating Another disadvantage of the known Agglomerierverfahren using chemical additives is that the latex viscosity increases sharply, whereby its subsequent concentration is problematic and leads to strong coagulum ,

It is also known to agglomerate latices under pressure. (B.D. Jones, Lecture Fourth Rubber Techno! · Conf. London, May 1962), In this case, the latex is pressed in the homogenizer under high pressure through a narrow nozzle. The resulting shear forces cause the latex particles to agglomerate. Disadvantages of this process are the narrow limits set by the composition of the starting latices and the agglomerating agents.

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Object of the invention

The aim of the invention is the elimination of the known Aggloinerierverfahren adhering disadvantages. Thus, in the case of chemical agglomeration, premature coagulation of the latices should be avoided, as should a strong increase in viscosity, so as not to complicate the subsequent concentration. The narrow limits set by the agglomeration, in particular in the pressure agglomeration of the latex composition and the agglomerating agents, are to be considerably extended, and the economics of the agglomeration processes are to be increased.

Explanation of the essence of the invention

It is an object of the invention to provide a process for agglomerating butadiene copolymer latices which satisfies the above requirements. The object is achieved according to the invention by adding a butadiene copolymer latex having less than 40 % solids content as agglomerating agent o, ol to o , 5%, based on the content of pesticides ,, of a mixture of a) one or more nonionic emulsifiers having an average HLB value of Io to Y] and b) an emulsion copolymer of vinylaromatic, dienes, unsaturated carboxylic acids and 2 to 4o % esters of unsaturated carboxylic acids, preferably esterification products of the dieis-alder adducts of maleic acid, wherein the esters to s o, l to 2o%, preferably 2 to 8% saponified present, is added, wherein the quantitative ratio of a) to b) 1 : 4 to 4: 1. After mixing with the latex still o, 2 % sodium or potassium silicofluoride are added, after which the latex under

a pressure of 25o to 6oo kg / cm set and then relaxed. Finally, a pH of at least 7 is set with alkali.

For the agglomeration of butadiene copolymer latices according to the invention, in contrast to the processes known hitherto, latices can be used which have been prepared using conventional emulsifiers for emulsion polymerization. Known emulsifiers are z. E. Alkali salts of long-chain fatty acids with a chain length of 12 to 18 carbon atoms and alkyl and alkylarylsulfonic acids. A commonly used and very active anionic emulsifier is the sodium or potassium salt of disproportionated abietic acid). Although cationic emulsifiers are scarcely used, z, B, hydrochlorides of long-chain fatty amines and reaction products of fatty acids with dialkylaminoalkanols or also ester amines can be used for the preparation of starting latex for the agglomeration of the invention. All known polymerization processes such as Zo B. can be used to prepare the latices. the batch process, the addition process or the continuous cascade process are used.

Suitable nonionic emulsifiers as a constituent of the agglomerating agent mixture according to the invention are ion-condensation products of long-chain alcohols, phenols or fatty acids with alkylene oxides, especially of ethylene oxide. Very effective are polyether polythioethers. When a mixture of non-ionic emulsifiers is used, it is not necessary for each one to have an HLB value of Io to 17 at v / e, but it is sufficient for _f when the entire mixture has determined this value. So it would be z. For example, it is possible to mix 40% of a nonionic emulsifier having an HLB value of 8 with 6 % of a nonionic emulsifier having an HLB of 15 to achieve an average value of 12.2 and within HLB vVert limits of the present invention to stay.

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The mixing component b) of the agglomerating agent mixture used according to the invention is a copolymer in latex form of vinylaromatic, dienes and unsaturated carboxylic acids and / or 2 to 4o% esters of unsaturated carboxylic acids, as comonomers, preferably esterification products of the Diels-Alder adducts of maleic acid, the Ester to o, l to 2o>, preferably 2 to 8%, saponified.

The second constituent of the mixture according to the invention is a polymer latex consisting of vinylaromatic compounds, dienes and unsaturated carboxylic acids, 2 to 4o % esters of unsaturated carboxylic acids as comonomers, preferably esterification products of the maleic aniside adducts of maleic acid, the esters o, l to 2o %, preferably saponified 2 to 8 % .

The preparation of such polymer latices is described in DWP 124 42o: they are u. a. suitable as emulsifiers, stabilizers, dispersants, thickeners and coating compositions.

The agglomeration processes according to the invention are particularly suitable Copolymerisatlatices with Veresterungsprodakten the Diels-Ald ^ r adducts of butadiene and maleic acid as comonomers and maleic acid itself with Nonylphenolpolyäthylenoxidalkoholen, Pettalkoholpolyäthylenoxidalkoholen, Polyäthylenoxidalkoholen or copolymers of ethylene oxide with propylene oxide.

By using the agglomerating agent mixture according to the invention, it is possible to agglomerate a wide range of butadiene copolymerization without having to adhere to narrow limits of agglomeration conditions as hitherto. That is, according to the process of the present invention, little difference in latex composition or quality or small differences in agglomerant concentration is lost

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previously lead to significant differences in the agglomeration process.

This effect is surprising for the person skilled in the art, since the amount of the individual components of the agglomerating agent mixture according to the invention used on its own is very critical. To effect z. B. Polyäthylenoxidverbindungen only at a very specific concentration maximum agglomeration and only a certain starting latex. Even in the case of deviations of 0.5 % of the agglomeration mean, such serious differences occur that in the subsequent concentration a maximum final solids content is achieved which is significantly lower than in the case of the optimum starting latex without the above

slight deviation in the amount of agglomerating agent;

On an industrial scale, such deviations necessarily have an even stronger effect, not to speak. from the inevitably rapidly increasing coagulum content.

Likewise, the other component of the Agglomeriermittelmischung invention, d. H. a Copolymerlatex prepared according to DD-PS 12442o, used alone, not to a desired agglomeration, but causes a rapid increase in viscosity or even complete thickening of the starting latex, whereby further processing is impossible.

The agglomeration process according to the invention avoids premature coagulation and a strong increase in viscosity.

Unp Ausfu hr; sbe ispiele. '

The invention will be explained in more detail below with reference to exemplary embodiments, wherein the quantities (T) are in parts by weight. For comparison with the invention

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- 7 - filO

According Agglomeration Verfa.hren also agglomeration experiments were carried out according to the prior art. To this was prepared a latex of 7o T butadiene, 3o T styrene and 3.8%, based on monomers, sodium salt of disproportionated abietic acid having a total solids content of 32% and an average particle size of 7o nm - called Latex A -.

example 1

To loo T latex A were o, o25%, based on latex solids, a mixture consisting of 2o T polyoxyethyleneoxypropylenoleate with a HLB of 11 and 80 T of a polymer isatlatex prepared according to Example 3 of DD-PS 124 42o added.

Example 2 (not according to the invention)

To 100% of latex A was added 0.25%, based on latex solids, of polyoxyethyleneoxypropylene oleate having an HLB of 11.

Example 3 (according to the invention)

To loo T latex A were o, o25%, based on latex solids, of a polymer latex prepared according to Example 3 of DD-PS 124 42o added.

Example 4

To 100% of latex A was added 0, 5%, based on latex solids, of the mixture from Example 1.

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Example ^

To loo T latex A o, o45%, based on latex solids, the mixture of Example 1 were added. All latex blends were stirred for 20 minutes after addition of 0.1 % sodium silicofluoride, followed by compression to 35o kg / cm and immediate relaxation.

With sodium hydroxide, the pH was adjusted to 7. The results of the agglomeration are summarized in Table 1.

Table 11

Example I ¹ Tr,

Avg. Particle size before the agglomerates after the agglomerate

rxerung

• in nm

merxation in nm

7o 7o 7o 7o 7o

148 74

coagulates 148 156

A further latex was prepared from 66 parts of butadiene, 12 parts of styrene and 22 parts of acrylonitrile. The emulsifier used was a mixture of 1.4%, based on monomers of the sodium salt of a fatty acid mixture having 12 to 16 carbon atoms and o, 8% alkylarylsulfonato The total solids content the latex was 34%, the average particle size was 58 nm. This latex is further called latex B.

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Example 6

To loo T latex B were, based on solids, o, o2-5 % of a mixture of 80 T polyoxyethylene monostearate having an HLB value of 16 and 2o T of a polymer latex prepared according to Example 5 of DD-PS 124 42o added,

Example 7 (not according to the invention)

0.025% polyoxyethylene monostearate were added with an HLB of 16 to loo T Latex B, based on Latexfestutoff. ,

Example ji (not according to the invention)

Loo T latex B were, based on latex solid ,. o, p25% of a polymer latex prepared according to In game 5 DD-PS 124 42o, was added.

Example ^

Too latex B, based on latex solid, was added to the oil of Example 6, o.sup.5 % .

Be itpiel Io

To loo T latex B were, based on latex solid, o, o45% of the mixture of Example 6 given. All Latexmischungeri were intensely stirred for 12o minutes after addition of o, 2 % potassium silicofluoride, then

2 to 580 kg / cm compressed and immediately relaxed. Iialium hydroxide was then used to adjust the pH to 7 «

The results are shown in Table 2.

- Io .-

- Io -

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Table 2 Avg. particle size Example no. before the agglomerate in nm after agglomeration in nm 58 135 6 58 66 7 58 .not measurable 8th 58 132 9 58 154 io

In comparison with conventional agglomeration methods, agglomerated latices according to the invention can be concentrated to a higher solids content while the viscosity remains the same.

The agglomerated latex mixtures of Examples 1 to Io were concentrated by evaporation to a viscosity of looo cps (loo Pa.s). The solids values achieved are to be taken from Table 3. The latices not agglomerated according to the invention (Examples 2, 3, 7 and 8 ) show significantly worse results or could not be concentrated.

Table 3

Agglomerated latices achieved solids content from example: at loo Pa.s 1 56% 2 4-7.5% (not inventive according to) 3. _ tt 4 55.5 % 5 57 % 6 55% 7 8 46% " 9 54% io 56 %

Claims (1)

- ¹¹ - 21 3741 Erfindunpsanspruch Process for agglomerating butadiene copolymer latices with less than 4o % solids content by means of chemical agglomerating agents and the use of "pressure, characterized in that as agglomerating agent o, oil to o, 5%, based on solids content, a mixture of a) one or more nonionic emulsifiers having an average HLB value of Io to 17 and b) a Smulungscopolymerisat of vinyl aromatics, dienes, unsaturated carboxylic acids and 2 to 4o% esters of unsaturated carboxylic acids, preferably esterification of the Diels-Alder adducts of maleic acid, wherein the esters to sialo to 2o%, preferably 2 to 8% saponified , wherein the amount ratio of a) to b) 1: 4 to 4: 1, after mixing with the latex still up to o, 2 %. Sodium or potassium silicofluoride added and the latex in a conventional manner under a pressure from 2 ^ o to 6oo kg / cm and then released, after which by means of alkali also in a known manner, a pH of at least 7 is set. - 12