DD232288A1 - RUBBER PREPARATION AND VULCANISES MANUFACTURED THEREOF - Google Patents

Abstract

The object was to develop a rubber compound using non-silicate mineral fillers with the aim that the vulcanizates produced from it have improved mechanical properties. This invention, which is useful in the rubber industry for the manufacture of a wide variety of rubber articles, relates to a rubber composition and vulcanizates made therefrom comprising: a) from 5 to 75% by weight of non-silicate mineral fillers treated with inorganic colloidal SiO 2 solutions having particle sizes of 5 nm to 150 nm during and after treatment processes of these fillers and subsequently subjected to an organic coating with reactive adhesion promoters and these contain in concentrations of 0.1 wt .-% to 10 wt .-% at the surface, b) 25 to 95 Ma .-% of a rubber, rubber mixture or a mixture of thermoplastic polymers and rubbers and c) in addition to conventional aids, additives and vulcanizing agents in usual concentrations, based on the amount of polymer, contains. This rubber compound has improved properties, in particular increased voltage values (moduli) in the small technically interesting deformation regions.

Description

Field of application of the invention

The invention relates to rubber mixtures and vulcanizates which can be prepared therefrom, the technical performance of which has been improved by using non-silica modified mineral fillers in relation to such vulcanizates using pure mineral fillers or adsorptively hydrophobized mineral fillers in a known manner.

Characteristic of the known technical solutions

It has long been known that the economic and / or mechanical properties of natural or synthetic polymers can be improved by mineral or synthetic inorganic substances as fillers. Through the use of a wide range of different fillers, the performance properties of polymers that can represent elastomers as well as thermoplastics and thermosets can be largely influenced. Of particular interest as fillers are in addition to the numerous siliceous fillers, such as. For example, synthetic silicas and silicates, layered silicates, quartz, glass and aminosilicates and precipitated metal oxides, hydroxides or carbonates, non-silicate mineral substances such as natural chalk, crushed limestone (calcite), marble or anhydrite.

Since non-silicate minerals, such as chalk, calcite or anhydrite, occur in large deposits and are relatively easy to prepare, their use as fillers proves to be economically particularly advantageous.

In order to incorporate larger amounts of fillers, which generally have hydrophilic surfaces, into hydrophobic or non-polar polymers, it is generally necessary to improve their polymer compatibility by surface modification. In addition, the adhesion between polymer and filler in the interface is dependent on the processing or flow properties of rubber compounds and the mechanical properties of the corresponding vulcanizates. Improvements in mechanical properties can only be achieved if an adhesion improvement can be achieved in the polymer filler interface. In contrast, the flow behavior of a mixture can be substantially improved by good and stable particle dispersion.

Adhesion promoters are used to increase the polymer compatibility of fillers and to achieve improved interfacial adhesion. The active principle of the adhesion promoters is that they generally have reactive groups which form a chemical bond with the silanol groups of silicate fillers and form chemical bonds via further functional groups with the corresponding polymer matrix or at least exert strong interactions. Typical adhesion promoters are organometallic compounds such as organosilanes, organo-titanates, and the like. Since the cheap mineral fillers based on metal carbonates or metal sulfates have no reactive surfaces which have OH groups, they are a modification with z. B. organo-silane coupling agents not accessible. Mineral non-silicate fillers usually have a hydrophilic surface. This results in disadvantages in the wetting of the filler by the rubber and only very weak interactions in the boundary layer. During the mixing process, therefore, it is not possible to dissolve firmly bonded filler agglomerates. It turns out for the vulcanizates produced from a low level of property. The flow behavior is only slightly influenced due to the lack of interactions. In contrast, silanization of natural or synthetic siliceous fillers results in vulcanizates with markedly improved property levels. At the same time, the positive properties of the organophilic adhesion promoter appear, which counteract a strong agglomeration, and thus an increase in viscosity.

Silane coupling agents that are unable to undergo reactive modification on non-silica mineral fillers (CaCO3, BaSO4, etc.) therefore can not produce improved properties in such vulcanizates. This fact proves to be a major disadvantage in the development of high-performance mineral non-silica filled rubber materials based on cheap carbonatic or sulphate minerals such as chalk, limestone or anhydrite. For this reason, numerous methods have been proposed to modify the surface of mineral non-silicate fillers so that a sensitivity to reactive coupling agents, preferably organosilanes results.

In addition to the treatment with phosphoric acid (JP 54037099), carbonaceous fillers have been coated with aluminum hydroxide (JP 54131619) and silicates to obtain a silanol- or hydroxyl-containing filler surface reactive with silanes.

While coprecipitations of carbonates and S1O2, preferably to increase the whiteness (US Pat. Nos. 2,470,577, 865,781, 3,152,001, 3,343,890 and ÖB-PS 838,903), have been proposed for the use of carbonates as pigments, silicate coating has been proposed of mineral carbonates and sulfates in situ precipitations of metal silicates in the presence of the fillers carried out as the z. In US Pat. Nos. 2,259,481, 2,259, 482,259, 483, 4167, 423 and DE-OS 2524863. In this case, the production of fillers with a surface layer of metal silicates by adding alkali metal to a water suspension of the mineral material alkali metal silicate solutions, which are then precipitated by the addition of metal salts and optionally with the addition of acids, the corresponding metal silicates on the surface of the mineral material. For the candidate meta silicates a broad spectrum of metals is given. ... _; ... ...

In JP 52129751 and JP 52127791, e.g. described the deposition of lead silicates for modification of carbonate fillers with silane-reactive surfaces.

Another method for Coatung of mineral carbonates with S1O2 consists in the hydrolysis of Kieselsäureestern in GegenwartvonCaC0 ₃ -Fü! Lstoffen (JP 55113619). U.S. Patent 4,374,178 has disclosed the use of soluble silicates such as Na-ortho silicate, Na-meta-silicate or sodium disilicate for the SiO ₂ coating of CaCO ₃ with the simultaneous addition of silane coupling agents.

The previously proposed method for modifying inorganic mineral fillers whose surfaces have no reactive OH groups, with the aim of a reaction with adhesion promoters such. As organo-silanes to achieve, have a number of disadvantages. These consist mainly in the relatively complicated procedures, the difficult to control in situ precipitation of metal silicates, in the required pH control and the use of costly substances such as metal salts or silicic acid esters.

Further, the per se having a high purity carbonic or sulfatic filler by Metallioneh, z. B. in the coating with heavy metal silicates (JP 52129751.52127791 or DE-OS 2524863, US-PS 4,167,423) enriched.

The use of soluble alkali silicates to coat CaCO ₃ favors the formation of larger aggregates of the finely divided carbonate coated with silicates, so that additional grinding effort is required.

Finally, all previous processes employ the use of finely divided mineral materials and can not be integrated into the treatment process of inorganic mineral or synthetic fillers, such as calcium carbonates or sulfates, whereby a significant economic advantage has been achieved.

From the disadvantages mentioned, it follows that none of the proposed methods has yet been put to commercial use.

Object of the invention

The object of the invention are rubber mixtures and vulcanizates obtainable therefrom with improved properties based on rubbers and non-silicate mineral or synthetic inorganic fillers.

Explanation of the essence of the invention

The object of the invention is to develop rubber compounds and vulcanizates which can be produced therefrom with improved properties by using modified non-silica mineral or synthetic fillers.

This object is achieved according to the invention by rubber mixtures or vulcanizates which can be produced therefrom

a) 5 to 75% by mass of non-silicate mineral or synthetic fillers which are subjected to inorganic coating by treatment with aqueous colloidal SiO 2 solutions with average particle sizes of 5 nm to 150 nm during wet classification or wet grinding or after other treatment processes and then with an organic coating were subjected to reactive adhesion promoters and these in concentrations between 0.1% by mass and 10% by mass in a firmly adhering layer,

b) 25 to 95% by weight of a rubber, rubber mixture or a mixture of rubbers and thermoplastic polymers and

c) furthermore contains customary auxiliaries, additives and vulcanizing agents in customary concentrations, based on the amount of polymer.

The mixture component a) preferably consists of readily available non-silicate mineral fillers modified according to the invention, such as chalk, ground limestone or anhydrite with a particle size range between 0.01 and ΙΟμ, ΓΤΙ.

It has surprisingly been found that treated with aqueous colloidal SiO ₂ solutions treated mineral, nichtiiicatische fillers, such as natural chalk, ground limestone or anhydrite, with a reactive surface, which allows to bind organic adhesion promoters by chemical coupling. It is particularly surprising that the inorganic coating with colloidal silicic acid solutions can also be carried out during the treatment process of mineral fillers, preferably by wet grinding, wherein the necessarily added dispersion aids, usually alkali metal phosphates, do not interfere with the coating process.

The preparation of the modified by an inorganic coating with colloidal SiO 2 solutions and thus capable of reacting with adhesion promoters mineral or synthetic fillers is done in a simple manner in that they are stirred or ground in aqueous suspension with the addition of an aqueous colloidal SiO 2 solution and after Separation of the excess SiO 2 solution may optionally be subjected to an acid wash. This is conveniently carried out by a dispersion of the treated filler in the 2- to 10-fold amount of water at pH values between 4 and 6. Subsequently, the coated product is separated by decantation or filtration and dried. The colloidal SiO 2 solutions to be used for the inorganic coating are characterized by their average particle size. For the modification of the fillers to be used for the preparation of the improved vulcanizates according to the invention, colloidal SiO ₂ solutions with average particle sizes of 5 to 150 nm are used. This SiO ₂ coating of non-silicate mineral or synthetic fillers is carried out with commercial aqueous colloidal SiO ₂ solutions which are free of metal ions.

If the SiO 2 treatment is carried out during the wet grinding, the time is determined by the duration of the grinding. The fillers treated according to the invention with colloidal SiO ₂ are expediently post-treated with a dilute acid solution at pH values between 4 and 6. This can be z. B. by stirring or washing with a 1 to 2% acetic acid. The time span between the SiO ₂ coating and the acidic aftertreatment is of no importance, so that, for example, the SiO ₂ -coated filler can be decanted over a prolonged period of time and then the acid aftertreatment can take place. The drying of the decanted, filtered or centrifuged material is carried out by known methods. The wrapping of the filler surface can be done completely or partially. Since a reactivity of the filler surface towards adhesion promoters is desired in the sense of the rubber material according to the invention, the degree of surface coverage of the filler by the colloidal SiO 2 particles is insignificant, if any chemical bonding of adhesion promoter molecules can take place, as is also the case with only partial cladding , The amount of colloidal SiO ₂ deposited on the surface of the filler particles may be between 0.1 and 10 mass%.

It is sufficient if sensitivity of the surface of the corresponding fillers to reactive adhesion promoters, preferably organosilanes, is achieved.

The coupling of the coated with colloidal SiO ₂ solutions fillers with a reactive coupling agent, preferably organosilanes, can be done either by the addition of these in the form of aqueous solutions or suspensions to the decanted with colloidal SiO ₂ modified filler, at any time with the dried product can be carried out according to the known silanization or in the known manner during the mixture preparation by the combined addition of modified filler and adhesion promoter.

Suitable fillers which are suitable for the modification according to the invention are all non-silicate mineral or synthetic particulate or fibrous fillers.

These are therefore non-silicate materials which are not to be confused with coprecipitates of silicate and non-silicate materials.

The SiO ₂ content produced by the process according to the invention is also to be distinguished from siliceous impurities or admixtures, such as sand or quartz, which may occasionally have the fillers mentioned.

Coupling agents are molecular bridges between the filler surface and a polymeric matrix. A distinction is made between bifunctional adhesion promoters of monofunctional adhesion promoters. Bifunctional reactive coupling agents have both reactive functional groups that can react with the filler surface, as well as functional groups that can form a chemical bond with the polymers, such as. B. vinyltriethoxysilane.

Monofunctional coupling agents are those which contain reactive functional groups directed towards the filler surface while the second group or grouping interacts with the polymer matrix in a system-specific interaction, such as

z. As hydrogen bonding, van der Waals interactions or acid-base interactions, but without forming chemical bonds, such as. As alkylchlorosilanes or phenylchlorosilanes.

As adhesion promoters for modification in the context of the process according to the invention, preference is given to using organosilanes.

The general formula

X ₃ Si-R

X denotes the hydrolyzable functional groups, usually alkoxy groups, such as. Ethoxy or methoxy groups, while R represents a carbon atom bonded to the Si atom moiety, which is either organophilic, as in the case of monofunctional alkylsilanes, or is reactive with the polymeric matrix, such as. As vinyl silane.

The modification of the fillers in the sense of the invention therefore includes all organosilanes which can react with the SiO 2 -coated filler surface. A review of the numerous organo-silane type compounds useful in this reaction is given in E. PLUEDDEMANN: Silan Coupling Agents, Plenum Publ. Corp., 1982.

Also silicon compounds of the type of silazanes or their functionalized derivatives, such as. As hexamethyldisilazane, are suitable for the reaction with the inventive SiO 2 -coated non-silicate mineral or synthetic fillers.

Although adhesion promoters of the organosilane type are preferably used in the process according to the invention, other organo-metal or organo-non-metal compounds, such. As organo-titanates, organo-borates or organo-phosphates, which have hydrolyzable or OH-reactive groups, suitable to react with the invention SiO ₂ -coated filler surface, and can thus be used as a primer in the context of the method according to the invention.

become. .. _ ..... - - -

To react the corresponding adhesion promoters with the SiO 2 -coated filler surface, these are brought into contact with the filler either individually or in a mixture of different adhesion promoters simultaneously or successively in the form of aqueous solutions or dispersions or dissolved or dispersed in solvents or solvent / water mixtures.

This can be done either after the SiO ₂ co-treatment, during or after the acid treatment or even after the drying of the SiO ₂ -coated filler at any time according to the known methods.

The concentration of adhesion promoter on the filler surface to be applied may be between 0.1 and 10%, with a concentration of 0.5 to 3% being preferred and sufficient to produce the desired modifying effect. The duration of contact of the SiO ₂ -coated filler with the adhesion promoter (s) and the temperature of the treatment, which can be carried out at room temperature or at temperatures up to 373 K, are not critical parameters of the process according to the invention.

It is a particular advantage of the inventive solution that both the inorganic modification by the SiO ₂ -Coatung and the organic modification by the reaction with adhesion promoters, for. B. by silanization, directly during the preparation of the fillers by wet classification and / or wet grinding without intermediate drying can be performed.

It is furthermore characteristic of the inventive Verfatiren that after the SiO ₂ -Coatung the mineral or synthetic non-silicate fillers to the surface-resultant OH groups, all chemical reactions can be carried out for silicate materials or SiO ₂ , as in K. UNGER: Porous Silica, Elsevier Sei. Publ. Comp., Amsterdam 1979 or R. ILER: The Chemistry of Silica, J. Wiley, New York 1979.

Thus, the modifying possibilities for non-silicate fillers, although the use of adhesion promoters is preferred, are considerably expanded in the context of the method according to the invention.

It has also been found that finely divided modified non-silicate mineral or synthetic fillers can be used in part for the substitution of precipitated silicas and low reinforcing carbon blacks. This opens up further opportunities for economical-vorteil.rezeptutgestaltung. It is characteristic of the modified fillers used that even very small amounts of the inorganic and organic coatings, the improved properties of the

vulcanizates according to the invention

These improvements result from:

- Improved dispersibility of the filler

- the formation of chemical bonds in the interface to the polymer and

- the specific interactions promoting effects of adhesion promoters.

Exemplary embodiments Example 1

10Og of wet-ground natural chalk (average particle diameter 3μπη) are stirred with 600ml of water in a flask with reflux condenser after addition of 30 ml of 30% colloidally disperse SiO ₂ solution with a mean particle diameter of 15μΓη at 353Kfürzwei hours. Thereafter, the liquid is decanted off, and after addition of 400 ml of 2% acetic acid, the filler suspension is stirred for one hour. It is then washed with water and the filler separated by decanting or centrifuging and dried at 383K.

The chemical analysis gives a SiO ₂ content of 1.8% SiO ₂ . The whiteness is 75.7% compared to 74% in the original sample.

Example 2:

With 100 g of ground limestone (calcite, average particle size 3μ.ιτι) is carried out according to Example 1. The SiO ₂ analysis yields a SiO ₂ content of 1.3% for the SiO ₂ -coated filler. The whiteness increases from 85.2% for the original sample to 88% for the SiO ₂ -coated sample.

Example 3:

100 g of anhydrite (average particle size 15μ, ητι) are treated according to Example 1. The chemical analysis is followed by an SiO ₂ content of 5.0 mass%.

Example 4:

This example demonstrates the use of the inventive method for modifying fillers by SiO ₂ co-cation during the process of processing chalk. 12 kg of a pre-classified dry chalk be with 8 kg of water with 12g Na5P ₃ Oioals dispersant than 60% strength by weight suspension of chalk with the addition of 400g of a 30% colloidally dispersed SiO ₂ solution in a dispersing device of known type (spindle mill) for two hours.

After decanting overnight, the supernatant liquid is removed and replaced with water, to which 160 ml of acetic acid are added. Subsequently, the suspension is stirred vigorously for two hours.

Thereafter, the SiO ₂ -coated chalk is filtered off with suction and the filter cake subjected to a thermal drying to a residual moisture content of 0.2 wt .-%. Finally, a pulverization takes place. The chemical analysis shows an SiO ₂ co-ordination of 3.2% by mass of SiO ₂ .

The pH of the chalk and the particle sizes are not changed compared to the non-application of SiO ₂ -Coatung.

Example 5:

This example shows the application of the method according to the invention for the modification of fillers by SiO ₂ co-treatment and subsequent reaction with a coupling agent-γ-aminopropyltriethoxysilane - during the process for the treatment of chalk.

An approach of 12 kg of a preclassified chalk and 8 kg of water and 12 g of Na ₅ P ₃ OiOaIs dispersant is carried out according to Example 4. However, after the addition of 160 ml of acetic acid while stirring, 300 ml of -γ-aminopropyltriethoxysilane are added; Thereafter, the process of Example 4 is continued.

The chemical analysis shows 2.7% SiO _{2 and} 1.3% nitrogen. Further evidence of the chalk silyl silanization can still be made by a color reaction with a slurry of the modified filler in an acetone / water mixture with a 10% sodium nitroprussate solution. In contrast to a comparative sample, the modified filler sample shows a color reaction from purple to violet with increasing time.

Example 6:

This example shows the hydrophobing of a chalk filler, prepared according to Example 1, by silanization with hexamethyldisilazane in the gas phase.

70g of an SiO ₂ -coated chalk filler of Example 1 are stirred after drying at 393K in a flask under vacuum and heated to 373-393K and treated with hexamethyldisilazane vapor passing through a second flask connected to the reaction flask and likewise heated Piston containing hexamethyldisilazane is generated. After 10 minutes, the connection of the flask is closed and the reaction flask is evacuated to remove the ammonia formed. After repeating the procedure four times, the silanization is complete. In this way, a hydrophobized chalk is obtained, which is not wetted by water and shows improved flowability. Compared to a blank, the hydrophobized chalk has a carbon content of 1%. Non-SiO ₂ -coated chalk, treated by the same method, has no hydrophobic properties, ie, does not react with hexamethyldisilazane.

Example 7:

This example shows the preparation of silane-modified fillers based on chalk, calcite and anhydrite, SiO ₂ -coated according to Examples 1 to 3, with solutions of organosilanes in alcohol / water mixtures.

70 g of the SiO ₂ -coated filler according to Betspiel 1,2 or 3 are dispersed in 200 ml of a methanol / water Gemisehes (10:90) and added to 6 ml of the corresponding silane. Thereafter, 2 to 3 drops of acetic acid are added and stirred for 30 minutes. After further stirring for 1 hour, the solid is filtered off, washed with methanol and dried for 2 hours in a drying oven.

The following silane concentrations are obtained on the respective fillers: - - ~

filler

., - Coating in Ma «- /»

Silanization in Ma .- / S chalk calcite anhydrite 1.7 1.3 5.1

Vinyltriethoxysilane 5 Si - CH = CH ₂ cyclohexenylethyltriethoxysilane s Si - CH ₀ CH,

Merkaptopropyltriethoxysilan

= oi -

2.1

3.6

1.5

6.8

1.5

2.1

0.7

1.2

0.4

Example 8:

This example shows the silanization of the SiO ₂ -coated fillers according to Examples 1 to 3 with phenyltrichlorosilane in one

organic solvents.

150g of the 383K dried fillers of Example 1,2 or 3 are suspended in 500ml toluene in a 2L 3 necked flask and heated to reflux for 48 hours after addition of 88g phenyltrichlorosilane. After cooling, the liquid phase is decanted off and the filler is washed with methanol, filtered off with suction and dried at 393 K.

The resulting fillers are hydrophobic and have the following degrees of silanization:

filler

Si0 ₂ -coating in Ma. -%

^ m Ma. ·

Sili i eruns, chalk calcite anhydrite 1.7

1.3

5.1

phenylsilane

= Si - (\ in Ha. -%

3.2

6.5

 ,8th

Example 9:

This example shows the hydrophobing of SiCV-coated chalk with dichlorodimethylsilane.

100 g of 473 K dried chalk are treated with a 10% solution of dichlorodimethylsilane in carbon tetrachloride and heated under reflux for 48 hours at 350 K. Thereafter, the solid is decanted off, washed several times with methanol and

dried at 353 to 363 K.

The prepared filler is not wetted by water.

Example 10:

This example relates to blend and vulcanizate production based on 50 phr chalk filled styrene butadiene rubber.

The mixtures were prepared in a micro-measuring kneader with 77 ml chamber volume at a chamber conduction temperature of 323 K in such a manner that 40 g of the rubber were kneaded for 1 minute and 20 g of the chalk mixed together with 1.2 g of ZnO and 0.8 g of stearic acid. After 10 minutes, the vulcanization system consisting of 0.8 g of sulfur, 0.68 g of CBS and 0.52 g of DPG is added to this mixture, and the mixture is homogenized for a further 5 minutes with a kneading shaft speed of 45 min ^-1 . that the mixtures and vulcanizates according to the invention have a considerable increase in stress if an organic coating with colloidal SiO _{2 is accompanied by} an organic coating

Jdaftvermittlern. (Silanes) follows. The different rubber-silane interactions cause stronger ^

Interactions a strong voltage increase ^. For example, at a relative elongation of 200% (see table), and for weaker interactions, a good stress compensation in the interface between rubber and filler with high elongation at break and stresses.

The flow properties of the blends, which are all characterized by low viscosities and low viscoelasticity, are only insignificantly changed in the case of stronger interactions.

VuIkaηisat and mixing values for 50 phr filler

coating O200 If % ML 1 + 15 a owned (Base CaCO ₃ , avg. (ε = 200%) 360 (2 min- ¹ (Max) Particle 015 μπι) MPa MPa 350 100 ⁰ C - S SBR LöOO / CaCOrun treated 2.3 3.7 230 34 0.58 2.2 SBR / CaC0 ₃ according to Example 1 2.3 3.7 34 0.60 1.8 SBR / CaCO ₃ according to Example 5 3.1 3.2 410 35 0.54 2.1 SBR / CaCO ₃ according to Example 7 (Cyclohexenyltrimethoxysilan) 2.3 4.6 260 33 0.59 2.0 SBR / CaCO ₃ according to Example 7 (Merkaptopropyltriethoxysilan) 2.9 3.2 35 0.54 2.1

a - relaxation rate according to G (t) = G {t ₀ ) t ^a Ig e _max - maximum relaxation time

Example 11: ~ '~ "" "

If rubber mixtures and vulcanizates according to Example 10 with fillers of different particle size are subjected to an inorganic coating with subsequent silanization (corresponding to Examples 1 to 9), it is found that in particular the fracture properties are substantially improved with decreasing particle size with respect to increasing elongation at break

Vulcanizate and blend properties for 50 phr of filler with change in base particle size of CaCO ₃

ML 1 + 15

Coating. σ ₂₀₀ o _b ε _ύ (2 min "¹; a _max

Particle size (μm) 100 ° C)

MPa MPa% ML - s

SBR 1500 / CaCOsuntreated 2.3 3.7 360 34 0.58 2.1 Particle size 15 ^ m SBR 1500 / CaCO ₃ 3.1 3.2 230 35 0.54 2.1 according to example 5 SBR1500 / CaCO ₃ untreated 2.3 4.4 380 35 0.61 1.9 Particle size 10 ^ m SBR 1500 / CaCO ₃ 2.5 4.1 370 36 0.57 2.1 according to example 5 SBR1500 / CaCO ₃ untreated 2.2 6.0 450 36 0.61 1.9 Particle size 5 μπι SBR 1500 / CaCO ₃ 2.6 7.5 400 35 • 0.59 1.9

according to example 5

a: lg0 - according to example 10

mix recipe

SBR 1500-100phr; Filler-50 phr; ZnO 3phr; Stearic acid - 1 phr; Sulfur - 2phr; CBSfN-cyclohexyl-benzothiazyl sulfenamide) -1,7 phr; DPG (diphenylguanidine) -1,7phr.

Claims (1)

Invention claim: Rubber compound and vulcanizates producable therefrom, characterized in that a) 5 to 75Ma .-% of mineral or synthetic non-silicate fillers, the inorganic coating by the treatment with aqueous colloidal SiO ₂ solutions having average particle sizes of 5 to 150 nm during the wet classification or wet grinding or after other work-up and then an organic Coating were subjected to reactive adhesion promoters and these in concentrations between 0.1 to 10Ma .-% in a firmly adhering layer, b) 25 to 95% by weight of a rubber, rubber mixture or a mixture of rubbers and thermoplastic polymers and c) in addition known processing aids, stabilizers, flame retardants, dyes and vulcanizing agents in conventional concentrations, based on the amount of polymer.