DE943256C - Process for the degradation of natural or / and synthetic rubber for the purpose of producing rubber mixtures or rubber solutions - Google Patents

Description

Process for the degradation of natural and / or synthetic rubber for the production of rubber mixtures or rubber solutions addendum to the patent 824258 The subject of patent 824 258 is a process for the production of rubber compounds or rubber solutions through the degradation of natural or synthetic rubber by heat treatment in devices such as rollers or kneaders, which is characterized is that zinc oleate or a mixture of zinc oleate and iron oleate is incorporated into the rubber will. This makes significant progress with regard to the degradation of rubber and other advantages. In particular, the effort and time required considerably reduced for the mastication process.

Further experiments and studies have shown that others Substances or mixtures of substances can be used as degradation agents. As degradation-promoting Agents according to the invention are salts that are composed of polyvalent cations, z. B. of magnesium, calcium, aluminum, zinc, lead, iron, nickel and cobalt and aliphatic or cycloaliphatic acids such as saturated or unsaturated Fatty acids, resin or paraffin oxidation fatty acids or aromatic acids, such as Benzoic acid, nitrobenzoic acid, alkyl-, aralkylbenzoic acid, benzoylbenzoic acid, phthalic acid monooleyl ester, Kre- sylnaphthylcarboxylic acid. The addition of zinc oleate as well as mixtures of zinc and iron oleate is the subject of the main patent. as Soap-forming cations also come in addition to those mentioned above, among others Copper salts and manganese salts are considered. The application of salts of these cations but is generally not recommended because they can exert poisonous effects. Salts of the type mentioned above can be used individually or in groups to be brought. It has been found that all these substances have the valuable property the degradation of natural and synthetic rubber to a considerable extent favor and exert other beneficial effects. They work among other things as activators, have a strong plasticizing effect and are able to add fillers and other additives to disperse.

The existing dismantling agents are used in the same way, as stated in the main patent, by adding the rubber or the rubber mixtures during processing with the aid of devices, such as rollers or kneaders, at temperatures over 50 °, e.g. B. between 60 and 1100, are incorporated, and the degradation with access to air is carried out. The prerequisite for the effectiveness of the dismantling kits is in general their solubility or fine dispersibility in the rubber compound.

The development of a large group of usable mining resources offers the advantage that you are not limited to the use of a few substances but rather the most suitable or the most easily accessible, depending on requirements Can choose fabrics.

As a result and through the use of mixtures that consist of two or The more the rubber-degrading salts exist, one is able to have degradation effects exercise in the desired gradation.

The best degradation effect is generally produced by iron salts. Cobalt, lead and nickel salts have a somewhat lower degradation effect than iron salts. By combining salts with different cations with the same or different types Carboxylic acids can be used with respect to breakdown agents of different efficiencies produce the rubber degradation and at the same time also the other properties of the Influence additives in the desired manner. You can still use the dismantling agents still other additives, such as plasticizers, esters, mineral oils, selective extracts (olefin-rich mineral oil fractions, which are separated by means of liquid sulphurous acid were incorporated) and the like, individually or in groups, and thereby also the properties and affect effects of the degradation agents, e.g. B. the incorporation of the degradation agents facilitate in the rubber compounds. When using dismantling agents which Containing larger amounts of iron soaps, in some cases the addition has to be made of anti-aging agents proven to be beneficial.

The invention is illustrated below using a few examples. Here the defo values (defo hardness and defoelasticity) determined. For comparison, the values (so-called blank values) are given in each case, which when processing the same rubber or the same rubber mixtures were found without the addition of dismantling agents.

Example I A rubber compound was applied to the roll with no additive of degrading agents at go ". The following blank values result: Mixing time in minutes (after 4 minutes of homogeneous mixing) o 2 4 8 10 I5 2300/34 2300/33 2300/34 2300/34 2300/33 2200/32 The same rubber compound were made 2 percent by weight of a decomposition agent added, which consists of 98 0 / o zinc salt of trans-fatty acid distillate with 20 /, ferric stearate. The following values were obtained: o 2 4 8 10 I5 2050/38 I550 / 33 I650 / 27 I600 / 25 I350 / 2I I250 / 21 Example 2 To prove that that the salts of saturated fatty acids also show the degradation effect, were the Example 1 rubber compound used when mixing on the roll; at 90 "2 weight percent of a decomposition agent incorporated, which consists of 98% chemically pure zinc stearate and 2 ° 10 Iron stearate.

The numbers below illustrate the degradation effect. The specified Values relate to the blank values given in Example 1.

Mixing time in minutes (after 4 minutes more homogeneous Mixture) o 2 4 8 10 I5 2050/29 I900 / 25 I650127 I600 / 25 I375 / 25 I250 / 23 Example 3 The rubber mixture according to Example 1 was on the roller 20/0 of a degradation agent incorporated, which is made from an intimate mixture of 85% lead phthalate and 15% ferric benzoate. o 2 4 8 10 I5 2225/32 2I00 / 3I 2050/29 I850 / 30 I850 / 28 I700 / 24 Example 4 Here the disintegrant was in solution or suspension with an olefin-rich selective extract applied. For comparison, the rubber mixture was on the one hand 20/0 of an olefin-rich one Selective extract alone, on the other hand with 20/0 of a 5 0/0 suspension of Nickel oleate treated in a selective extract.

Blank values after adding 20 /, of the selective extract: o 2 4 8 10 15 .2550 / 36 2450/32 2400/32 2350/35 2350/34 2250 / 3I

Claims (4)

5% suspension of nickel oleate in a selective extract, additive 20 / o: o 2 4 8 IO I5 2550/36 2500/34 2450/32 2400/35 2300/34 2050/29 Example 5 With an addition of 20 / o cobalt oleate, the following results were achieved: o 2 4 8 IO I5 2450/33 2400/33 2350/34 2350/35 2300/33 I950 / 29 Example 6 With the addition of 20 / o of a 50/0 strength solution of lead oleate in an olefin-rich selective extract the following results were achieved: o 2 4 8 IO I5 2400 / 3I 2350/32 2300/32 2250/32 2I50 / 29 I950 / 25 Example 7 With the addition of 20/0 of a mixed solution of 20 / o ferric oleate and 98 0 / o selective extract, the following results were achieved: o 2 4 8 IO I5 2750/38 2500/33 2350/33 2300/30 2300/29 2200/29 PATENT CLAIMS I. Procedure for the degradation of natural and / or synthetic rubber for the purpose of production of rubber mixtures or rubber solutions through the degradation of natural or synthetic rubber by heat treatment in devices such as rollers or Kneading, according to Patent 824 258, characterized in that the rubber or the rubber-containing mixtures are added salts that are formed from polyvalent cations, z. B. of magnesium, calcium, aluminum, zinc, lead, iron, nickel and cobalt and aliphatic or cycloaliphatic acids such as saturated or unsaturated Fatty acids, resin, naphthenic or paraffin oxidation fatty acids or aromatic Acids, such as benzoic acid, nitrobenzoic acid, alkyl-, aralkylbenzoic acid, benzoylbenzoic acid, Phthalic acid monooleic acid, hexylnaphthalenecarboxylic acid, excluding zinc oleate exist. 2. The method according to claim I, characterized by applying a Mixture of at least two rubber-degrading salts with the exclusion of a mixture of zinc oleate with iron oleate. 3. The method according to claims I and 2, characterized by application a degrading agent which, in addition to a rubber degrading salt or mixture of rubber-degrading salts and additives such as plasticizers, esters, mineral oils, Contains selective extracts, anti-aging agents, individually or in groups. 4. Process according to Claims I to 3, characterized in that the degradation process at temperatures above 50 °, preferably between 60 and 1100, at Air admission is carried out.