DE1301483B - Process for the production of aqueous butadiene polymer dispersions - Google Patents

Description

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Butadiene polymer dispersions produced by gators, such as addition products of ethylene oxide to emulsion copolymerization of butadiene with como-alkylphenols, optionally together with ionic monomers, such as styrene, acrylonitrile or acrylic esters, emulsifiers of the type mentioned above,
Are prepared are in general extraordinary The polymerization can take place at normal pressure or

finely divided. Their viscosity can therefore already be carried out at a relatively high pressure, and low solids contents are so high that they only generally work at temperatures from 0 to difficult to handle. For some Verwen- 8O ⁰ C. For example, the polymerization can at dung purposes, however, are latexes 50 ⁰ C using potassium persulfate as held performed by at least 60 percent by weight of catalyst solid. Advantageous special advantage. io apply 0.01 to 1 percent by weight of potassium

Processes have therefore already been worked out, persulfate, based on the monomer phase. These allow the particle size of the butadiene, however, it is often advisable to polymerize the polymers during or after the polymerization, for example at 5 to 20 ° C., at a lower temperature. Thus, for example, further emulsions can be initiated continuously with the usual redox catalysts of the emulsion polymerization. Examples of such catalysts are to meter in large polymer particles: Cumene hydroperoxide-hydroxyrnethansulfonic acid obtained. But you are then during the sodium, cumene hydroperoxide-dihydroxyacetone, whole polymerization on the verge of coagulation, zoyl peroxide-sorbose and diisopropylbenzene hydro- and the polymerization is extraordinarily long-peroxide-tetraethylene pentamine.
sam (cf. Houben-Weyl, B. 14/1, edition 1961, 20 The polymerization can be up to 100% conversion ge-p. 352 and 686). leads to be. However, it is mostly beneficial, yes

In the case of the British patent specification 758 622 to be broken off at lower conversions, since in the case of well-known processes, the freeze agglomeration, stepped conversion, crosslinked products are formed. As a stopping agent, you can freeze the cool stuff for this and use it again after a while, e.g. B. sodium dimethyl thawed. The process has the disadvantage that, in addition to dithiocarbamate, hydroxylamine, hydrazine hydrate, quite large amounts of energy are required. Hydroquinone and 2-mercaptobenzothiazole.
It is also known that butadiene polymer disper- The pH should be before the start of the polymerization

Sions due to the addition of electrolytes, organic over 6, preferably between 8 and 11, are. Man Solvents or high molecular weight wasserlös- 3 ° can him z. B. with potassium or sodium hydroxide borrowed substances such as polyvinyl alcohol, polyvinyl methyl or carbonate and with ammonia or alkyl ethers and methyl cellulose, to agglomerate, with amines adjusting.

the pH value can often be changed at the same time.

got to. These processes also have the disadvantage that merization only led to a conversion of up to 50 to 70% they are difficult to carry out and often turn into, generally dispersions with solid formation lead to considerable amounts of coagulate, held at around 20 to 35%. These dispersions

It has now been found that aqueous dispersions can easily be converted into solid butadiene polymer dispersions in the customary manner concentrate through copolymer contents of 60 to 65%, e.g. through sation of 30 to 89.5 percent by weight of butadiene, evaporation of the water at normal pressure or ver-10 up to 40 percent by weight styrene and / or acrylic 4 ° reduced pressure at temperatures between 20 and nitrile and other monomers in aqueous emul- 100 ° C, preferably between 40 and 70 ° C, where sion at pH values above 6 with advantage, the dispersions can advantageously be prepared continuously, if one keeps 0.5 to gung as further monomers. The dispersions are after the Aufkon-10 Weight percent alkali or ammonium salts center even with a solids content of about Ethylenically unsaturated dicarboxylic acids and 0 to 45 65% still flow well.

20 percent by weight (meth) acrylic acid ester from 1 to The process according to the invention has opposite

Alkanols containing 12 carbon atoms give the known processes the main advantage that applies, the percentages by weight referring to the high polymerization rate without all monomers are related. With a preferred agglomerating additives, such as electrolytes, This preferred embodiment of the process uses 5 ° dispersions obtained on the basis of the particles as a salt of an unsaturated dicarboxylic acid, a size of the copolymers is relatively low salt the maleic acid, the fumaric acid and / or the viscous and the easily high solids-itaconic acid. As dicarboxylic acids can also be kept in concentrate without being in the process Question glutaconic acid, 3-methylglutaconic acid, dihyn- form significant amounts of coagulate. the dromuconic acid, methylenemalonic acid, citraconic acid, 55 dispersions are particularly suitable for solid mesaconic acid, 2-methyleneglutaric acid and 3-methy "- held from 60 percent by weight for coating Igenglutaric acid. of textiles, carpet reverse side coatings and

The polymerization can be carried out in a manner customary per se, such as for the production of coatings and foams using the customary catalysts, rubber.

Emulsifying and dispersing aids, regulators and 60 From the USA. Patent Clirift 2,631,997 it is Buffer substances are carried out. Suitable known to be vinylidene compounds in water emulsifiers are for example the sodium, riger emulsion at pH values of preferably potassium or ammonium salts of saturated or 8 to 11.5 can polymerize. In this USA.-unsaturated Fatty acids, such as stearic acid and oil patent specification, maleic acid is also incidentally substituted acid. The well-known from rosin is also mentioned. However, as shown in column 6 of the USA Resin soaps are suitable, as are salts of patent specification 2,631,997, in this case be-alkyl sulfonates, Alkyl sulfates and alkyl aryl sulfo-known processes are highly viscous polymer dispensers. There are also non-ionic emulsions. It is therefore surprising that the invented

according to the process butadiene polymer dispersions of relatively low viscosity can be obtained.

The parts given in the following examples are parts by weight. The viscosity measurements were carried out with a commercially available Rotovisco device (Haake, Berlin) with a shear rate of D = 16.32 seconds " ¹ .

Examples 1 to 13

0.2 parts are added to a mixture of 130 parts of water. p-menthane hydroperoxide, 0.15 part of iron sulfate (FeSO ₄ · 7H ₂ O), 0.005 part of hydroquinone, 3 parts of a commercial mixture of the potassium salts of hydrogenated tallow fatty acids, 0.5 part of trisodium phosphate, 0.2 part of potassium pyrophosphate, 0.1 part of tert. -Dodecyl mercaptan and 1.6 parts of potassium itaconate. 98.4 parts of monomer mixture are added, the pH of the batch is adjusted to 10.5 with about 0.1 part of potassium hydroxide and polymerization is carried out with the addition of a solution of 0.1 part of sodium hydroxymethanesulfinate in parts of water to a conversion of about 70 % (6 to 8 hours) at 15 ° C. Then you break through

ίο addition of 0.3 parts of sodium dimethyldithiocarbamate and concentrates under evaporation of water at 50 to 6O ⁰ C under reduced pressure to a solids content of 61 to 66 weight percent. The monomers used and the results are summarized in the table below.

example Monomers in parts Solids content
in percent by weight V.
(cP) 1
2
3
4th
5
6th
7 *)
8th**)
9 **)
10 ***)
U * # * #)
12th
13th 68.9 butadiene, 29.5 styrene, 1.6 K itaconate
68.9 butadiene, 29.5 styrene, 1.6 K fumarate
68.9 butadiene, 29.5 styrene, 1.6 K maleate
64.0 butadiene, 34.4 styrene, 1.6 K maleate
59.0 butadiene, 39.2 styrene, 1.6 K maleate
68.9 butadiene, 19.7 styrene 1.6 K maleate 9.8 acrylonitrile ...
68.9 butadiene, 29.5 styrene, 1.6 K maleate
68.9 butadiene, 29.5 styrene, 1.6 K itaconate
68.9 butadiene, 29.5 styrene, 1.6 K maleate
68.9 butadiene, 29.5 styrene, 1.6 K maleate
69.5 butadiene, 29.7 styrene, 0.8 K maleate
59.0 butadiene, 24.6 styrene 1.6 K-maleate 14.8 n-butyl acrylate
29.5 butadiene, 68.9 styrene 1.6 K maleate 64.5
64.8
61.5
64.6
66.0
61.4
63.0
63.2
62.7
60.5
61.8
63.4
61.6 974
1000
986
1000
1020
952
1080
1050
1140
985
1055
1020
370

*) 3 parts of K-oleate are used as emulsifier.

**) The emulsifier used is a mixture of 2 parts K oleate and 1 part resin soap. ***) The emulsifier used is a mixture of 1.5 parts of potassium oleate and 1.5 parts of a commercially available sodium paraffin sulfonate

with about 15 carbon atoms containing paraffin chains are used. ****) 3 parts of K-oleate are used as emulsifier; Polymerization at 50 ° C. with 0.3 parts of potassium persulfate.

Comparative experiments

a) As indicated in Example 9, a mixture of 70 parts of butadiene and 30 parts of styrene is polymerized without the addition of potassium maleate at pH 10.5. A butadiene polymer dispersion is obtained which has a viscosity η = 1000 cP even at a solids content of 45.9 percent by weight.

b) If the polymerization is carried out as described under a), but 3 parts of a commercially available mixture of the potassium salts of hydrogenated tallow fatty acids are used as the emulsifier, a butadiene polymer dispersion is obtained which has a viscosity η -1170 cP with a solids content of 46 percent by weight.

Claims (1)

Claim: Process for the preparation of aqueous butadiene polymer dispersions by copolymerization of 30 to 89.5 percent by weight butadiene, 10 to 50 percent by weight styrene and / or Acrylonitrile and other monomers in aqueous emulsion at pH values above 6, thereby characterized in that 0.5 to 10 percent by weight of alkali or Ammonium salts of ethylenically unsaturated dicarboxylic acids and 0 to 20 percent by weight (Meth) acrylic acid esters of 1 to 12 carbon atoms containing alkanols are used, wherein the percentages by weight are based on the total monomers.