DE1494312B - Process for the production of aqueous dispersions from synthetic elastomers - Google Patents

Description

i "2

Synthetic rubber latexes, as they are ζ. B. in the German patent specification 854 573 finally Emulsion polymerization are incurred in large describes a process for the production of water quantities in trade. The use of such poor dispersions of polyisobutylene, with filled latices is limited, since the resulting action of shear forces polyisobutylene produced binders, films, coatings or large amounts (up to 30%) of emulsifiers and bad rubber protective colloids are incorporated and subsequently Have properties. this mixture without the use of solution synthetic rubber vulcanizates is dispersed in water with good physical agents. On the other hand, no properties are obtained when fillers are used. The disadvantage here is if synthetic rubber is used on the mixing roller so that no ready-to-use dispersions are obtained, or in an internal mixer with light-colored active filling The resulting dispersions must first be in a substances as well as vulcanizing agents and further chewing further work step through relatively auftschuk auxiliaries mixed homogeneously and these maneuverable measures such as centrifuging, creaming, vulcanized practically anhydrous mixtures. The freezing, by electrophoresis or the like., Of a Production of such reinforced synthetic rubber- 15 frees most of the emulsifier and protective colloid Vulcanizates made from corresponding synthetic rubber should be technically usable. It is Mixtures in the form of an aqueous dispersion, namely a well-known fact that the rubber ion has not been possible so far. technical values of ready-made known are only processes which the articles of manufacture become with increasing protective colloid content of the worsen the preparation of aqueous dispersions of synthetic 20 dispersions.

tables or natural elastomers by dispersing object of the invention is a method for yawing of solid elastomer mixtures in water Manufacture of aqueous dispersions from synthetic materials describe the action of shear forces, tables elastomers by dispersing a solid Which protective colloids, such as casein, Elain, glue, etc., elastomer mixture, the fillers, wetting agents, Wetting agents, rubber auxiliaries or the like, but no alkaline substances and protective colloids as well contain active reinforcing fillers. Elastomers, if necessary vulcanizing agents and other chewing mixtures, which only contains a content of inactive chuk auxiliaries, in water under the fillers have, favor the dispersing application of shear forces, but without use these mixtures in water. of organic solvents, which thereby ge-tried on the other hand, according to these known 30, it is characterized that such solid elastomer processes Such dispersions, which, however, are mixtures used as fillers, light-colored The content of light-colored active reinforcing fillers has reinforcing fillers and water should be used as protective colloids, no technically soluble or water-swellable salts of polyacrylics are obtained, stable dispersions, which are acidic or water-soluble or water-swellable Contain reinforcing fillers in the elastomer portion of the Disper- 35 polyacrylic acid amides, sion homogeneously and finely divided. Since the With the help of these dispersions it is possible for the first time water is not absorbed by the mixture, with the usual uses in the latex industry here only gritty suspensions or working methods reinforced vulcanizates made of syn sponge-like Obtain masses which technically produce thetic elastomers in their are useless. For dispersions of synthetic rubber properties those VuI tables Elastomers with a content of light colored canisates are not inferior to those made of light colored active filler active ingredients Reinforcing fillers, however, consist of anhydrous elastomers containing substances Considerable mixes have been produced for the reasons given below. The ones from the technical interest. Dispersions prepared according to the invention receive-In British patent 538 505 will surpass a 45 NEN vulcanizates in their rubber technology process for the production of artificial dispersible values and their usage properties Sions made of rubber or synthetic rubber - those made from conventional elastomer latex Similar polymers are described, whereby one is relatively vulcanizates.

large amounts of a cationic soap, e.g. B. Cetyl- The dispersions according to the invention are

ammonium bromide as a dispersant, if necessary 5 ° prepared as follows:

together with vulcanizing agents, pigments, from an elastomer or a mixture of Fillers or the like, which with the dispersant two or more elastomers, which optionally are compatible, may still contain natural rubber under the influence of mechanical action, and light-colored Forces incorporated into the rubber and the mi-active fillers is put on a mixing mill Schung then dispersed in water. 55 or starved in an internal mixer no active reinforcing fillers to reinforce shear forces in a manner known per se turn. Mixture produced, which according to Austrian patent 120 863 auxiliaries, such as anti-aging agents, light protection is the usual it is known to contain aqueous dispersions of vulcanizing agents or plasticizers. Among other Sized or unvulcanized rubber, regrind, 60 exposure to strong shear forces are in this Factice od. The like. To produce this solid mixture of wetting agents, alkaline substances as well Masses under the action of shear forces and which are to be used according to the claimed method Use of alkalis and proportionate protective colloids and, if necessary, also moderately large amounts of protective colloids, such as casein, vulcanization chemicals evenly distributed and Elain or the like, with the exclusion of organic solutions, the whole approach worked through until one medium dispersed in water. This did not result in a completely homogeneous mixture. Out For practical reasons, it is advisable to use fillers as components of the mixture, parts of the elastomer mixture mentioned here

Admit order. This mixture is under the further action of shear forces, preferably in an internal mixer, gradually adding water in small proportions.

The water is absorbed by the mixture, with a dispersion of the first Type water-in-oil forms. With further gradual addition of water in small portions it finally occurs Phase reversal occurs and one is formed

Made from synthetic rubber or natural rubber vulcanizates can also be used. The amount of the natural rubber in the total elastomer should not exceed 49%.

The term »light-colored reinforcing fillers« includes pyrogenic and precipitated silicas, precipitated Calcium silicates, precipitated aluminum silicates and alumina gel understood. These bright active fillers can be used either individually or in combination

Oil-in-water type dispersion. From this io schung to be used together. Depending on the The moment the mixture quickly becomes more and more requirements that are placed on the product,

You can also use other fillers such as kaolin, silica, chalk, surface-treated chalk, zinc

softer and finally runny. From here on, the water can be added more quickly and in larger proportions will. The resulting dispersion is extremely fine

oxide or magnesium oxide.

part and contains 90% particles with a finished diameter of 15 denier produced according to the invention up to 1.5 μ, while only 10% of persions can also be used in rubber technology

common aids,

Particles have a diameter of 1.5 to 3 μ. The particles of this dispersion contain the bright ones active fillers and the other ingredients in

like thickeners and

sensitizing substances, e.g. B. polyglycol ether, Silicofluoride, zinc salts, as well as buffer subcompletely homogeneous mixture with the rubber. 20 punch can be added. As wetting agents are anion-these Dispersions are resistant to temperature-fluctuating and non-ionic capillary-active substances and stable and suitable against mechanical influences. Skill has proven to be particularly advantageous can be diluted as required by adding water, turning potassium oleate, water-soluble resin, without coagulation occurring. soaps, polyalkylene oxide derivatives and fatty alcohol

In the preparation of the disulfates according to the invention, alkylbenzenesulfonates with 12 to 24 carbon emulsions It has proven to be useful, together with atoms of matter, as well as dialkyl esters of sulfobernliche Vulcanization chemicals with the exception of the stinic acid proved.

Sulfur in the practically anhydrous mixture of 0.5 to 10% of the wetting agents, pre-polymer, light active fillers, rubber - preferably 2 to 5%, based on the disperse phase, Incorporate auxiliaries and dispersants. 3 ° d. H. based on the elastomer to be dispersed separately and regardless of this, the sulfur mixture is used.

by suitable measures in an aqueous sus- As protective colloids are according to the invention in

Pension transferred, for example by milling water-soluble or at least water-swellable with water and wetting agents in a ball mill, salts of polyacrylic acid or water-soluble or or by precipitation in the aqueous phase in the presence of water-swellable polyacrylamides in amounts of 0.5% protective colloids. This aqueous sulfur up to 10%, preferably 1 to 5%, based on the suspension, for example so-called colloid-dispersing elastomer mixture, is used,
sulfur, the finished aqueous dispersion, a 10% aqueous solution of the invention

which contains all the other constituents, mixed in, according to usable polyacrylic acid amides shows in advantageously only shortly before they are used. 40 25 ° C, measured in the Höppler viscometer, a Vis-Durch this measure of keeping the viscosity separate from 10,000 to 250,000 cP. To be favoured Sulfur suspension is avoided that the sulfur uses polyacrylamides whose 10% strength on the elastomer in the aqueous dispersion solution a viscosity of 50,000 to 100,000 cP may act prematurely vulcanizing. has. As water-soluble salts of polyacrylic acid are

In this way, the shelf life of the 45 used is those whose 10% aqueous Lö dispersion, especially at elevated temperature, solution at 25 ° C, measured in the Höppler viscometer, improved. has a viscosity of 200 to 270 00OcP,

In some cases, however, it may be advantageous, preferably 200 to 50,000 cps. These salts of all vulcanization chemicals including polyacrylic acids contain alkali metal des as cations Sulfur does not get into the dry mixture of 50 or ammonium and substituted ammonium ions. The main components of the elastomer mixture are mainly used as alkaline substances

work and to disperse with this together in water, but separately from this these vulcanization chemicals and to suspend the sulfur together in water.

Polymers can be used as elastomers which can be used according to the invention conjugated dienes, such as butadiene (1,3), isoprene, 2,3-dimethylbutadiene (l, 3), chloroprene, cyanobuta-

Alkali hydroxides, ammonia or amines are used. The amount depends on the type of filler and the amount of filler from, but is normally 1 to 10%, preferably 2 to 6%, based on the disperse Phase.

Furthermore, the rubber mixtures to be dispersed in accordance with the present invention can contain further common additives such as vulcanization chemicals,

dien- (1, 3), as well as copolymers of these conjugate- 60 anti-aging agents, light stabilizers, ozone protection agents

dated dienes with each other or with other inadequate, plasticizers, blowing agents, dyes, pig-

Contain saturated compounds, disinfectants or the like that can be copolymerized with them,

fertilize in question, also cis-1,4-polymers of the The effectiveness of these auxiliaries or additives

Butadiene or isoprene, copolymers are made when you use them according to the invention

Ethylene and propylene, polyethylene sulfochloride, 65 anhydrous rubber mixture added and common-

Polyalkylene polysulfides, or mixtures of the above sam dispersed with this in water, better than if

specified polymers, if necessary together the same substances in the same amount in syn-

with a proportion of natural rubber. Regenerated rubber latex can also be incorporated. This ver

improvement of the effectiveness of auxiliary substances or additives comes from the fact that they are in the processing inside the rubber particles of the aqueous Dispersion are located and can develop their full effectiveness there. When adding the auxiliary and Additives to synthetic rubber latex, on the other hand, are distributed in the aqueous phase of the Latex and cannot develop their full effectiveness in the rubber particles of the latex.

In addition to sulfur, peroxides and the usual accelerators can be used alone or in admixture with one another.

The dispersions prepared by the claimed process have a pH value which is preferred is between 8 and 10. They are very finely divided; at least 90% of the particles have one Diameter of less than 1.5 μ, the remainder has a diameter of up to 3 μ.

The viscosity of the dispersions depends on the starting materials and the amount added Water. Thick, paste-like dispersions can be produced which can be diluted with water are without coagulation occurring. Also against mechanical influences, shear effects and temperature influences the dispersions are stable.

It has also been shown that the dispersions prepared by the claimed process with electro-neutral as well as with negatively charged particles containing synthetic latices and Mix artificially produced dispersions of other types.

The dispersions of the invention can be used to good effect in many fields of technology and vulcanized before or after molding.

The parts of the elastomer mixtures given in the examples below are parts by weight, based on 100 parts of the elastomers. The amount of wetting agent, protective colloid and alkali used is based on 100 parts of the disperse phase, i.e. H. to 100 parts of the elastomer mixture to be dispersed.

For example

The following mixtures with varying silica content were produced on a mixing roller at one roller temperature manufactured from 60 to 100 ° C:

100 parts of butadiene-styrene copolymer

(Styrene content 30%), 50 to 90 parts of precipitated silica, 2 parts of stearic acid,
7 parts magnesium oxide, 1.5 parts zinc diethyl dithiocarbamate, 0.3 part zinc salt of mercaptobenzothiazole, 5 parts zinc oxide active.

The following were homogeneously incorporated into these mixtures in an internal mixer at 60 ° C:

2 parts of oleyl hexaethylene glycol ether,

3 parts of potassium hydroxide, as 40% water

solution,

1.5 parts of polyacrylamide, in the form of a _6s

10% aqueous swelling.

Then, with further mechanical processing, water was slowly added in small portions up to Phase reversal was added and the dispersion was adjusted to a solids content of 50%.

The dispersions obtained had the following key figures:

pH 9 to 9.5

Particle size .. 90% to 1.5 μ

1Ο ^ο / ο1,5 ^ 8 3μ

Viscosity η measured with a rotational

viscometer at 20 ° C and one

Shear rate of 22 sea- ¹ 2500

up to 3000 cP

Before the test films were produced, 3 parts of sulfur were added to each of the dispersions as a 50% sulfur suspension, stirred in.

The dispersions produced in this way were diluted with 10% water, defoamed, deaerated and 25 cm ³ each on a horizontal, with a circulating

ao the edge provided, 200 x 200 mm large glass plate evenly distributed and 24 hours on the Air dried. The films had a uniform thickness averaging 0.3 mm. They were subsequently Vulcanized in hot air at 100 ° C for 20 minutes.

To compare the vulcanizates produced from the aqueous dispersion with such vulcanizates can be made from the same rubber compound, but without dispersion in water have been, from a corresponding, practically anhydrous, 90 parts of precipitated silica containing rubber compound samples and heated in a vulcanizing press. The tensile strength and the elongation at break of the samples were according to DIN 53504, the tear strength according to DIN 53507 determined. The technical rubber values obtained are summarized in the table.

45

Fallen Tear Tear Continue Bemer Silica
(Weight strain strength tear resistance kun
gene*) parts) (° / o) (kg / cm ² ) (kg / cm) 0 240 24 0.8 L, F 50 620 40 4.0 D, F 60 480 58 4.0 D, F 80 500 84 28.2 D, F 90 500 98 33.8 D, F 90 470 101 35 M, P

55 *) L = latex,

D = produced according to the claimed process,
F = freely heated,

M = made from the dry rubber mixture, P = heated in the press.

Example 2

The following was done on a mixing roll at 60 to 100 ° C Mixture made:

100 parts of butadiene-acrylonitrile copolymer

(Acrylonitrile content: 30%),
30 parts of precipitated silica,
30 parts of dioctyl phthalate,
1.5 parts stearic acid,
1.0 part triethanolamine.

The following substances were homogeneously incorporated into this mixture one after the other in a screw kneader:

2 parts of the amine salt of tetrapropylene benzene sulfone

acid,
5 parts of morpholine,

3 parts of polyammonium acrylate, as 20% aq

serious swelling.

Water was then slowly added in small portions with continued application of shear forces and the dispersion adjusted to a dry content of 40%.

Before the production of the test films were

2 parts zinc diethyl dithiocarbamate,
2 parts zinc oxide active,
2 parts sulfur

added in the form of a 50% aqueous paste.

The rubber test of 20 minutes

Films vulcanized at 150 ° C gave the following values:

Elongation at break 480%

Tensile strength 73 kg / cm ²

Tear strength 5.3 kg / cm

Example 3

. A mixture of the following composition was obtained under the conditions given in Example 2 made with water to a dispersion with a dry content of 50%:

The test films vulcanized at 150 ° C for 20 minutes showed the following technical rubber values:

Elongation at break 270%

Tensile strength 70 kg / cm ²

Tear strength 10 kg / cm

Example 5:

As indicated in Example 2, a dispersion of the following composition was made up with water set a solids content of 50%:

00 parts Butyl rubber Sulfur, (Isobutylene content: 97%), Zinc oxide active. 30 parts precipitated silica, 20 parts Polypropylene adipate, 5 parts Titanium dioxide, 2 parts Stearic acid, 2 parts Triethanolamine, 2 parts Octadecenyl sulfuric acid ester (Na-SaIz), 4 pieces Morpholine, 3 parts Polyammonium acrylate, as 20% watery swelling, 1.5 parts zinc diethyl dithiocarbamate, 1.5 parts of tetramethylthiuram disulfide, 2 parts 5 parts

51 parts of butadiene-styrene copolymer

(Styrene content: 30%) ,.
49 parts natural rubber,
75 parts of precipitated silica,

2 parts stearic acid,

7 parts magnesium oxide,

1.5 parts of zinc diethyl dithiocarbamate.

0.3 part of the zinc salt of mercaptobenzothiazole,

5 parts zinc oxide, active,

3 parts sulfur,

3 parts potassium oleate,

5 parts ■ morpholine,

3 parts of polyammonium acrylate, as 20% strength

watery swelling,
1.0 part sodium alginate.

The rubber test of the films vulcanized at 100 ° C for 20 minutes gave the following values:

Elongation at break ............ 450%

^; Tensile strength 100 kg / cm ²

Tear strength ......... 31.7 kg / cm

Example 4 ■. ;.

As stated in Example 2, a 40% aqueous polychloroprene dispersion was prepared with the following composition ^{: ::}

Parts polychloroprene,

30 parts of precipitated silica,

10 parts of precipitated aluminum silicate,

10 parts zinc oxide active,
0.5 part of 2-mercaptoimidazoline,

4 parts of nonylphenyldecaethylene glycol ether,

5 parts of morpholine,

1.0 part triethanolamine,
4 parts of polyammonium acrylate, as 10% strength
watery swelling.

The films vulcanized at 160 ° C for 20 minutes had the following technical rubber values:

Elongation at break 850%

Tensile strength 100 kg / cm ²

Tear strength 18 kg / cm

Examples

4P As indicated in Example 2, a dispersion was obtained the following composition adjusted with water to a dry content of 50%:

40 parts of butadiene-acrylonitrile copolymer

(Acrylonitrile content: 30%), 60 parts of oil-extended butadiene-styrene

Rubber,.
40 parts of fumed silica,.

5 parts of precipitated aluminum silicate, 2 parts of stearic acid,

2 parts of the potassium salt of rosin, 1.0 part of triethanolamine,

5 parts of morpholine,

4 parts of polyammonium acrylate, as a 10% aqueous swelling,

2 parts zinc diethyl dithiocarbamate, 2 parts zinc oxide active,

2 parts sulfur.

The test films vulcanized at 150 ° C for 20 minutes had the following technical rubber values:

Elongation at break 440%

Tensile strength 73 kg / cm ²

Tear strength 20 kg / cm

Example 7

As indicated in Example 1, a dispersion was prepared with the following composition:

909 548/9

• 40 parts of butadiene-styrene copolymer

(Styrene content: 24%), ■■ ^;

Parts of chlorosulphonated polyethylene, parts of precipitated silica, '.. ■■

5. parts precipitated aluminum silicate,.

2 parts triethanolamine,

2 parts of octadecenylpentaethylene glycol ether, 5 parts of morpholine, '. ■ ;: ^· ■ '.

4 parts of polyacrylamide, as 10% aqueous •. ■ "■ Source." ■■■ "'

The following vulcanizing agents were used:

2 parts of zinc oxide, ■, ■,.

2 parts of zinc diethyl dithiocarbamate, 2 parts of sulfur,.

based on 100 parts of butadiene-styrene copolymer, furthermore. . '■■: -. ■

25.0 parts of lead oxide,. ".". '■■ 1.5 parts of dipentamethylene thiuram tetrasulfide, 0.5 part of tetramethylthiuram disulfide, 0.2 part of mercaptobenzothiazyl disulfide, - _: -. · -.

based on 100 parts of chlorosulfonated polyethylene.

The rubber test of 20 minutes

Films vulcanized at 150 ° C gave the following values:

Elongation at break 500% *

Tensile strength .C ^; ^:: ': KU \' - ^S: 85 kg / cm ² Tear strength 14 kg / cm

■ "■■ ' ^: ■■ ■" ■■■■ Example'8 ' ■ '■' ■

A dispersion of the following composition was prepared under the conditions specified in Example 1: ■. ■ '···. . : ^ 'X

51 parts of chlorosulfonated polyethylene, 49 parts of natural rubber.
30 parts of precipitated silica, ■■ '■ "■ 20 parts of ^ titanium dioxide, ^ ■ ·. ^ ·'" ^ 10 parts-: magnesium oxide, J-

10 parts: Ziriköxyd active,
. 1.25 parts hydrogenated rosin, 1.0 part stearic acid,
1.0 part light stabilizer based on paraffin, 1.25 parts mercaptobenzothiazyl disulfide, 0.2 part tetramethylthiurammohosulfide, 0.75 part sulfur, .. ,, '
2.0 parts of a- (Na-sulfonyl) - bis- (ethyl-hexyl) -

succinate ,. '■ ".,.'. ':. ■ · 1.0 part triethanolamine,
2.0 parts of potassium hydroxide, as 40%. ..... _; aqueous solution,

5.0 parts of polyacrylic acid amide, as 10% strength watery swelling,

adjusted with water to a solids content of 50%.

The films vulcanized at 150 ° C for 30 minutes showed the following technical rubber values:

Tensile strength., 125 kg / cm ²

Elongation at break. ^: . . · '.'. ■: ... ^: ... 530%
Tear strength 16 kg / cm

' ^: ■ ·' ■■ '- ^; ■■■ '■' ■ · Example 9

As indicated in Example 1, a dispersion of the following composition was made up with water set a solids content of 50%:

Parts of cis-l ^ -polyisoprene, '...' ■ · ■ '

40 parts _: precipitated silica,

2 parts of stearic acid,

3 parts> triethanolamine,

1.0 part light protection agent based on paraffin,

2 parts of zinc diethyl dithiocarbamate.

2 parts · ■ · Zinc oxide active,;

2 parts of sulfur, · .- ■: ■.

2 parts of the salt of a naphthalenesulfonic acid.;

Condensation product,
5 parts of potassium hydroxide, as 40% aqueous

Solution,
1.5 parts of polyacrylic acid amide, as 10% strength

watery swelling.

The films vulcanized for 30 minutes at 100 ^° C. in hot air had the following technical rubber values: ';'■. ■ "

Elongation at break ............ 800%;

Tensile strength .... .... 130 kg / cm ²

Tear strength. ........ 19 kg / cm

Claims (2)

Patent claims: 1. Process for the preparation of aqueous dispersions from synthetic elastomers by dispersing a solid. Elastomer mixture, the fillers, wetting agents, alkaline substances and protective colloids and, if applicable Contains vulcanizing agents and other rubber auxiliaries, 'in water when applied of shear forces, but without the use of organic solvents, thereby characterized in that such solid elastomer mixtures light-colored reinforcing fillers are used as fillers and water-soluble or water-swellable as protective colloids Contain salts of polyacrylic acid or water-soluble or water-swellable polyacrylic acid amides. 2. The method according to claim 1, characterized in that that the elastomeric mixture is based on up to 49 weight percent natural rubber on the total elastomer content. .