DE1244390B - Process for regenerating vulcanizates containing synthetic rubbers - Google Patents

Description

GERMAN #m PATENT OFFICE

EXTENSION PLAN C08d
German class: 39 b -10

Number: 1244 390

File number: C 31225IV d / 39 b

J 244 390 filing date: October 23, 1963

Opened on: July 13, 1967

Compared to the regeneration of natural rubber vulcanizates, vulcanizates require synthetic rubbers contain an increased amount of plasticizer, possibly also in connection with chemical Dismantling agents. Here, the plasticizers should be as swelling or regenerating agents as possible represent. However, since the individual plasticizers often do not have sufficient properties The use of plasticizer mixtures is expedient and customary. To the influence of atmospheric oxygen on the regeneration process, it is common to use the regeneration process in to be carried out in a water vapor atmosphere.

For example, monoarylhydrazines, such as phenylhydrazine, are suitable as chemical breakdown agents the French patent specification 853 577 and that serving in smaller doses as an anti-aging agent Phenyl-beta-naphthylamine has become known from US Pat. No. 2,478,826. There are also their reaction products with aldehydes and ketones, such as diphenylhydrazone, as degradation agents been used.

However, with the introduction of the stereospecific synthetic rubber, it has been found that the known regenerants do not or under the usual conditions these rubbers in any case are not able to open up to a sufficient extent, so that an economic exploitation by vulcanizates in which such synthetic rubbers are contained was questioned. With With the aid of the claimed process, stereospecific rubbers, in particular cis-1,4-polybutadiene, can also be used containing vulcanizates, regenerate well under economically justifiable conditions.

The invention relates to a method for regenerating synthetic rubbers containing Vulcanizates using plasticizer mixtures and amines and / or hydrazines, which is characterized in that addition products of halides of metals are used as degradation agents the II. main group and subgroup of the periodic table of the elements of amines and / or hydrazines be used.

The use of addition products of chlorides of calcium and zinc with diamines and hydrazines in conjunction with phenylhydrazine and cyclohexylamine is particularly advantageous because these salts also destroy tissue components present in the waste in a known manner and tissue-free regenerates can be obtained in this way.

Process for regenerating synthetic
Vulcanizates containing rubbers

Applicant:

Continental Gummi-Werke Aktiengesellschaft,
Hanover

Named as inventor:

Dr. Herbert Hildebrandt, Hanover

The abovementioned degradation agents are advantageously obtained in amounts between 0.3 and 3 percent by weight

ao on the vulcanizates.

The effect of such degradation agents after the claimed process was not to be expected, since the use of monoarylhydrazines or monoarylhydrazones has not led to any satisfactory success

a5 has leads. The same applies to long-chain amines, mercaptans and disulfides. Even the common one Use of plasticizers and zinc chloride, calcium chloride and sodium hydroxide led to no satisfactory result. Even a combination of the phenylhydrazones with the mentioned inorganic ones Compounds did not lead to a satisfactory one when the components were added separately Success in the depolymerization of stereospecific rubbers.

The chlorides and bromides of magnesium, strontium and cadmium also have a similar effect Sense. However, tissue residues are not or not completely broken down when they are used. the end for this reason, preference will generally be given to the chlorides of zinc and calcium.

Embodiment 1

The milled waste from synthetic rubbers, mainly from cis-polybutadiene, is made in the solution kneader with about 10 percent by weight of a plasticizer mixture of 4 parts dipentene, 4 parts Tall oil and 2 parts of a highly aromatic tar distillate with the addition of 1 percent by weight of the Phenylhydrazine zinc chloride complex mixed.

The mixture obtained is introduced into the preheated regeneration vessel and at temperatures between 150 and 190 ° C within 4 hours

709 610/58 +

Claims (2)

plasticized. In five parallel tests carried out side by side, the proportion of undigested waste averaged 8%, but always below 10%, while the proportion of undigested vulcanizate when using phenylhydrazone from phenylhydrazine and acetone with the simultaneous addition of zinc chloride was an average of 29%, but always was over 25%. Exemplary embodiment 2 The procedure was as in exemplary embodiment 1, but using 15 percent by weight of the plasticizer combination according to exemplary embodiment 1 and 2 percent by weight of the cyclohexylamine zinc chloride complex. The proportion of undigested material after a breakdown time of 4 hours was on average 9.5% in five tests, but always below 12%. Patent claims: 1. Process for the regeneration of synthetic rubbers containing VuIkanisaten using plasticizer mixtures and amines and / or hydrazines, thereby characterized in that addition products of halides of metals are used as degradation agents the II. main group and subgroup of the Periodic Table of the Elements of amines or hydrazines be used. 2. The method according to claim 1, characterized in that addition products of Calcium chloride and zinc chloride can be used on diamines and hydrazines, respectively. Considered publications:
French Patent No. 853 577;
U.S. Patent No. 2478826.