DE833702C - Process for the production of rubber compounds - Google Patents

Description

Process for the production of rubber compounds During processing of rubber with reinforcing fillers, one arises depending on the type of filler and "the mixing conditions observed" a smaller or larger amount of bonded gum. This bonded rubber formation is to some extent desirable at various times.

It has been observed, however, that individual, highly active, light-colored reinforcing fillers in particular tend to form bound rubber to an extent that not only makes the production and processing of the filler mixtures much more difficult, but also calls into question the production of solutions and the usefulness of the vulcanizates . The formation of bonded rubber can even go so far that the use of the reinforcing filler becomes impossible. The difficulties in making mixes e.g. B. a batch of 1 5 volume percent of highly active silica on the mixing roll expressed even when using normal amounts of plasticizer before the complete recording of the filler through the rubber: in a detachment of the coat from the roll and a subsequent input and tearing thereof. The filler batch gave the impression of a pseudo vulcanizate.

This observation is confirmed by the high defoelasticity measured and sufficiently justifies the processing difficulties, e.g. B. when spraying (Extrusion), such mixtures.

Attempts at solving the filler batches in aliphatic and aromatic Hydrocarbons did not lead to a complete dissolution. It swelled particles remained. The bound gum was not in solution bring.

It has now been found that, by adding gel inhibitors, z. B. Ethylene glycol, triethanolamine, diglycol and other substances, if more appropriate Dosage the formation of bound gum is significantly reduced or avoided could be.

Using ethylene glycol, triabhanolamine, diglycol and others Substances belonging to a group which are summarized here under the collective term gel inhibitors succeeded in completely eliminating the aforementioned difficulties. With the help of the gel inhibitors, even more highly stuffed silica batches could be produced prepare and bring into solution. The ready mixes from these batches could can be injected properly without any noticeable deterioration in the vulcanizate of the level of physical values.

In addition to these changes in the raw mixture, there are now the essential ones Differences in the finished vulcanizate.

While a vulcanizate of the test mixtures given below without gel inhibitors with otherwise almost the same physical number level as the Comparison mixture with gel inhibitors (see example) for crack tests on the roll bending machine led to severe cracking in a very short time, the comparison volcano, sat with ethylene glycol a very satisfactory test result.

Large-scale tests carried out on tread compounds fully confirm this Extent the results of the laboratory tests.

The tread with bright, highly active fillers without gel inhibitors showed deep cracks and fractures in a short time in a large-scale test on car tires, so that such a tire turned out to be unusable. In contrast, behaved such a tread with the addition of gel inhibitors crack-resistant than the ' Tread mixtures of today's production level.

It was thus confirmed that the named disadvantages of highly active reinforcing fillers can be eliminated if the formation of the bound rubber is controlled, in particular reduced or even prevented by adding ethylene glycol, triethanolamine, diglyrcol and other gel inhibitors. This C7el inhibitors give the opportunity to Harrd, retaining and training 1 creation of high-quality properties of highly active reinforcing fillers to eliminate the disadvantages encountered and to make these highly active substances by some of them only technically usable.

Examples Two rubber test mixtures with the following composition: without gel- with gel- Inhibitors inhibitors Sheets 39; Moo. . . . . . . . . . . 62.0 62.5 Pyrogenically derived active silica ...... 24.8 25.1 Wool fat, neutral ... ... . ... 2.5 - Ethylene glycol ............ - 2.5 Zinc white ................ 5.1 5.2 Sulfur ................ 2.5 2.5 Mercaptobenzodiazole sulfide ................. 2.1 1.5 Diphenylguanidine ........ 1.0 0.7 100.0 100.0 resulted in the following test results: Defo values. . . . . . . . . . . . . . 2000 13.6 2000 4.7 Tensile strength (kg / cm =). . 298 294 Elongation at break (°;! O) ....... 655 665 DVM softness ........... 25 23 Resilience to impact (° / o). . . . . . . . 49 45 Wear (mm '). . . . . . . . . 151.2 161.2 Voltage value (300 °,% 0. ... 87 70 Tear strength ....... 38 38 Fatigue (250 ' 0 .. ...... 536o 2 4380 2 Attrition number) .................. 7345 10000 Crack test (roll bending machine Z, 30 ') ....... 55 450 The procedure described; n can be used with light-colored, active fillers as well as with carbon blacks, as well as with natural rubber and synthetic rubber mixtures. The gel inhibitors can be used either individually or as a mixture with one another.

Claims (1)

PATENT CLAIM: Process for the production of rubber compounds under the use of active, in particular highly active, light-colored fillers by adding gel inhibitors such as ethylene glycol, triethanolamine, diglycol.