Method for making a mixture from rubber or the like.

The invention relates to a process for the production of carbon black-containing mixtures of rubber or rubber-like materials with a preheating in the high frequency alternating field.

Since the pre-heating of rubber in hot air chambers is problematic, it has been proposed to preheat the rubber in the high-frequency alternating field. However, this type of preheating could not find a way into practice, because the vast number of types of rubber having a too low dielectric loss factor.

Further, it must be assumed, that are needed for the start of a mixing process in dependence on the temperature at which the rubber is fed into the kneader, different Zieträume for plasticating and decrystallisation. In addition, the local non-uniformity of heating cold rubber bales facilitated the emergence of rubber portions that are overfilled with highly active fillers and according to experience difficult or impossible to distribute in the other matrix. In addition, the time until the power consumption, so the time to actual mixing process of the toughness and hardness of the packed bales depends. This fact also leads to unevenness in production of the mixture. These problems arise in a particular degree with Schaufelknetern with interlocking blades; they are because of their design anyway heavy loadable.

The invention is further based on the realization that it expedient appeared because of the difficulties associated with the handling of soot in emulsion polymers soot add already in the latex phase, so as to shorten the further mixing work and the adverse granulation of carbon black off. The same is true for the solution polymers, since there would be even greater mix technical advantages best possible predispensing of soot because of low shear forces. but nevertheless meets the so-called Rußbatch limits. This is partly due to the variety of types of carbon blacks and the lack, not being able to check the carbon black used in the rubber goods manufacturer in gehörigem dimensions. For these reasons, the majority of the sludge is made of rubber mixtures waiving Rußbatch in practice.

These disadvantages are to be avoided due to the invention. In particular, is to be achieved, will to a certain extent but especially assumed in the production of rubber compounds of different properties of the same mixing conditions, from the same starting temperatures can, so that accordingly therefrom as created all conventional tread compounds for vehicle tires or all adhesive mixtures for the construction of automobile tires in the presence of a particular batches can be. The aim is to continue reducing the total mixing time.

This object is achieved in that the rubber od. Like. Only a part of the planned amount of soot and the rest will be added to the pre-heating in the terminal prior to treatment in the alternating field. Appropriately, the rubber is only initially added about a third of the intended ultimate amount of soot, which is preferably of amounts of carbon black in the order of about 5 - 15% (calculated on 100 parts of rubber) may exist.

For obvious reasons, should at this preheating not the vulcanization can be achieved, but as a rule, preheating to about 40 - 60 ° C provided. It is also important that such preheating is not about impulsively, but extended to a period to be determined by the Mischungszylklus. Accordingly, the preheat time can extend over several minutes. Therefore, a few percent of carbon black sufficient to ensure a sufficient dielectric loss work. The doctrine initially assumed in the high frequency preheat a relatively small amount of carbon black and to carry out the preheat over minutes, complements the usual mixing processes, without having to change significantly over time or of their technical complexity here, it must be mentioned that the effort is a suitable preheating system are reasonable in relation to expenditure for a mixing device.

Assuming for example from a Rußdosierung 5 to 15 parts of N 339 with SBR or OESBR from, so you can under the condition that a BR - Rußbatch similar composition is available, virtually all current cars treads for pneumatic tires of some Rußbatchtypen easily Making way. From a natural rubber Rußbatch comparable composition practically all lorry-tire rubber compounds and all steel cord adhesive mixtures could still be made. In EPDM, there is also the advantage that due to the invention, the light stability of the polymer can be improved, a problem that often arises in practice today.

To Hochfrequenzvorwärmung low filled carbon black batch to perform economically and the particular requirements, it is appropriate to determine before treatment in the alternating field, the weight, the temperature and the shape of the body to be treated, so that an accurate preheating function of these values ​​on can be carried out a reproducible temperature. It is particularly expedient in this case if for determining the shape of the treated rubber body one or more sources of radiation, such as infrared emitters are used, which responsive sensors must be assigned to these rays. It is thus possible, for example, determine the contours; the so-called form factor can then enter into the calculation of a low RF preheating. With such a device, the weight and / or the temperature can be determined.

Mixtures of rubber or the like. In this application are all mixtures consisting mainly of rubber or rubber-like materials and next may contain other surcharges, mandatory but must contain important for Hochfrequenzvorwärmung soot.

The adjoining the aforesaid preheating operations, providing for completion of the mixture can be of any type, in particular can here the proven so-called internal mixer are used whose casting time but should be a guideline for the duration and UHF preheating. This should - to the mixing procedure altogether not adversely affecting, as already mentioned - be limited to a maximum duration of a main mixing passage.

It is particularly advantageous if the further production of the mixture after the preheating in the dielectric field is performed in a single-stage process, but a tandem-mixing process is also possible in such a way that the mix of a running than ram kneader basic mixer without any intermediate storage to a ramless transported kneader exported finished mixer, preferably for both mixers kneaders are used with cooperating, preferably intermeshing, counter-rotating rotors.

Due to the invention it is advantageous if, in emulsion polymers and natural rubber, the first amount of soot in the latex phase and solution polymers, the first soot added in the solution phase.

In the drawing, a manufacturing facility for mixtures of rubber or the like. Shown schematically.

From stockpile 1 with carbon black batch over the form or in the form of skins of rubber reaches a level 2 at room temperature in the amount of 10 to 25 ° C. In sized amount of rubber in the UHF (ultra high frequency) is then heated preheater 3, namely to about 40 to 60 ° C.

Above an internal mixer 4 of known design are silos 5, 6 for other aggregates. The Silo 5 is a Rußbunker that Silo 6 contains non-reactive aggregates.

then takes place in an internal mixer 4 which further treatment with the addition of supplements or the soot from the silo 5, 6. The thus processed mixture passes into a discharge device 7. From there, the rubber to the so-called batch-off system 8. There is also the rubber cooled.

It should be noted that the rubber in the reservoir stock already contains a certain proportion of carbon black and that after treatment in the UHF field over the silo 5 further soot is supplied to the purposes of the invention.

In connection with the scale 2, but possibly also dispensing with a scale 2, an infrared device can be used to determine the properties of the rubber mixture. This infrared device can be configured as desired.

For the treatment and the composition of the rubber mixture the following examples are given (phr are parts by weight per 100 parts of rubber).

Example 1:

<tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">A mixture consisting of:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="char" char=",">100.0 phr</entry><entry namest="col2" nameend="col2" align="left">SBR 1712 (copolymer of 77% butadiene and 23% styrene, extendiert with 37.5 phr of highly aromatic oil)</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.0 phr</entry><entry namest="col2" nameend="col2" align="left">stearic</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">5.0 phr</entry><entry namest="col2" nameend="col2" align="left">zinc oxide</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">52.0 phr</entry><entry namest="col2" nameend="col2" align="left">active carbon black, type N 339</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">7.5 phr</entry><entry namest="col2" nameend="col2" align="left">aromatic mineral</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">3.5 phr</entry><entry namest="col2" nameend="col2" align="left">coumarone</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.5 phr</entry><entry namest="col2" nameend="col2" align="left">Antiaging agent IPPD</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">0.5 phr</entry><entry namest="col2" nameend="col2" align="left">Antiaging agent PBN</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.0 phr</entry><entry namest="col2" nameend="col2" align="left">Antiozonant wax</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.5 phr</entry><entry namest="col2" nameend="col2" align="left">accelerator CBS</entry></row><row><entry namest="col1" nameend="col1" align="char" char=","><u>1.5 phr</u></entry><entry namest="col2" nameend="col2" align="left">sulfur</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">174.0</entry><entry namest="col2" nameend="col2" /></row></tbody></tgroup></table></tables>

was prepared by the method described such that the first aliquot of a batch consisting of 100.0 phr OE-SBR 1712 and 20.0 phr of carbon black N 339, which had been already added to the rubber in the latex phase during manufacture, two and a half minutes in the RF field of 3 times 60 kw heated, and then added to the non-reactive substances in the compounder.

The mixing time savings in the production of the basic mixture to the conventional method was 35%.

After the final mixing, the mixtures produced in this way showed no variations, either in its processing behavior nor in the physical values, after vulcanization.

Example 2:

<tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">A mixture consisting of (all data in phr):</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="char" char=",">100.0</entry><entry namest="col2" nameend="col2" align="left">Smoked sheets, Mooneyplast.ML-4: 65</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">2.5</entry><entry namest="col2" nameend="col2" align="left">stearic</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">7.5</entry><entry namest="col2" nameend="col2" align="left">zinc oxide</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">50.0</entry><entry namest="col2" nameend="col2" align="left">Carbon black N 220</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">5.0</entry><entry namest="col2" nameend="col2" align="left">aromatic mineral</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">5.0</entry><entry namest="col2" nameend="col2" align="left">coumarone</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.5</entry><entry namest="col2" nameend="col2" align="left">Antiaging agent IPPD</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">0.5</entry><entry namest="col2" nameend="col2" align="left">Antiaging agent PBN</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.0</entry><entry namest="col2" nameend="col2" align="left">Antiozonant wax</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.5</entry><entry namest="col2" nameend="col2" align="left">accelerator CBS</entry></row><row><entry namest="col1" nameend="col1" align="char" char=","><u>1.5</u></entry><entry namest="col2" nameend="col2" align="left">sulfur</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">174.0</entry><entry namest="col2" nameend="col2" /></row></tbody></tgroup></table></tables>

was prepared as by the process described that the first aliquot of a carbon black batch consisting of 100.0 phr smoked sheets and 10 phr of carbon black N 220 was pre-mixed in a kneader. This batch was heated for two minutes on high-frequency field of 4 times 60 kw prior to further processing, and then mixed in the non-reactive substances in the compounder.

The mixing time saving compared to the conventional method was able to be reduced from four to two and a half minutes.

Also in this case, both the characteristics of the uncured compounds as well as the values ​​of the vulcanizates (after mixing of the reactive substances) were identical.

Example 3:

<tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col2" align="left">A mixture consisting of:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="char" char=",">100.0 phr</entry><entry namest="col2" nameend="col2" align="left">EPDM rubber (terpolymer consisting of 65% ethylene, 30% propylene and 5% ethylidenenorbornene)</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">1.0 phr</entry><entry namest="col2" nameend="col2" align="left">stearic</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">150.0 phr</entry><entry namest="col2" nameend="col2" align="left">FEF carbon black, type N 550</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">150.0 phr</entry><entry namest="col2" nameend="col2" align="left">paraffinic mineral oil</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">0.5</entry><entry namest="col2" nameend="col2" align="left">Antiaging agent IPPD</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">3.5</entry><entry namest="col2" nameend="col2" align="left">Dicumylperoxide (40%)</entry></row><row><entry namest="col1" nameend="col1" align="char" char=","><u>1.5</u></entry><entry namest="col2" nameend="col2" align="left">triallyl</entry></row><row><entry namest="col1" nameend="col1" align="char" char=",">406.5</entry><entry namest="col2" nameend="col2" /></row></tbody></tgroup></table></tables>

was prepared in such a way by the process described in that an aliquot of a Rußmasterbatches consisting of 100.0 phr EPDM rubber and 50 phr FEF-carbon black, which had been already added during production in the solution phase to the rubber, in a high frequency field of 3 preheated times 60 kw three minutes and then the non-reactive substances were added in a kneader.

The mixture was prepared in an over the conventional method to 40% shorter in turn completely the same process both the raw mix and the vulcanizates.