DE2457446A1 - IMPROVING THE GRIP OF RUBBER MIXTURES OR CUTTING - Google Patents

Description

Improvement of the grip of chewy chew mixes or blends

The invention relates to improving the grip of either natural rubber, polyisoprene rubber, Styrene butadiene rubber, polybutadiene rubber, Ethylene - propylene - terpolymer rubber, Nitryl butadiene rubber and silicone rubber mixtures produced on dry and wet road surface and on dry and wet Ice, especially for tire treads or shoe soles, these mixtures in addition to conventional vulcanization aids Contain reinforcing substances and are vulcanized with sulfur or peroxides.

With a view to a future ban on spiked tires Various plans were sought to provide vehicle tires with treads that would be suitable for all seasons and no longer mechanically attack the road surface as strongly. It has numerous Attempts given to the grip of tires, in particular on wet roads and on particularly dangerous, "wet" ice by achieving a mechanical To increase the effect. For example, in

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BAD ORiGiMAL

Tire treads coarse foreign bodies such as small stones, cement particles, walnut shells, hard rubber, Steel chips or wool, plastic balls, etc. incorporated. However, these measures only worked little or not at all, they. sometimes even led to a deterioration in the tread properties all in all. The salient difficulty in incorporating such parts into mixes was in the lack of adhesion of these parts to the surrounding rubber compound, which means that under mechanical stress the particles fell out immediately, reducing the usable volume of gum mass.

It has also been proposed for tire treads to produce a rubber mixture based on rubbers which can be crosslinked with sulfur, which an extremely high proportion of reinforcing filler namely silica in precipitated form and possibly carbon black in small proportions and a coupling agent Contains base of silane compounds. These tread compounds provide excellent abrasion values and at the same time also on wet and icy roads surprise good traction, in some situations However, a tire with such a tread is still inferior to a tire with a studded tread.

From so-called light-filled rubber misery is also known, reinforcing fillers such as kaolin, small amounts of precipitated silica, alumina hydrate, Calcium carbonate and the like by means of the vulcanization system used (sulfur vulcanization or peroxide crosslinking) coordinated silane coupling agent for Use improvement of physical values.

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These silane adhesion promoters, their structure, their effect and their application have been described several times been (cf. the magazine "Gummi - Asbest und Kunststoffe" 8/74, pages 600 - 604, as well as the use of silanes, brochure from UNION CARBIDE from 1973, Revue Generale du Caoutchouc et des Plastiques, 50/1973, S -, - 377-381).

Taking this prior art into account, the object of the invention was to improve the grip of To increase tire treads even on ice so that a real replacement for spiked tires is created, i.e. material to be found in the rubber compound to bind that this remains in the mixture even under mechanical and thermal stresses.

Surprisingly, it has now been found that a tire is able to fulfill this task when the treads - Mixture as reinforcing filler 10 150 parts by weight of silica in precipitated form alone? or in combination with 0-100 parts by weight of carbon black and 5-50 parts by weight of one with a monomeric silane

adhesion promoter of the general structure R 'Si (OR) ₃

pretreated silicon carbide, sand or quartz with grain sizes greater than 0.01 mm, preferably between 0.01 mm and 0.5 mm. These mentioned materials are not used as reinforcing fillers, but rather as a rigid body, which due to the adhesion that can be achieved with the silanes in the rubber, the coefficients of friction the barrel mixes, especially on wet ones and icy road surface significantly. The known mixtures as reinforcing fillers The materials used were, for example, kieselguhr, quartz, aluminum, corundum and the like, more, but those there as microscopic particles with specific

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2 very large surfaces from 20 m / g to even

250 m / g and above are used, while those according to the invention are used Additives, silicon carbide, quartz and sand in grain sizes between 0.01 and 0.5 mm are used.

Further aspects which are important for achieving the object of the invention are to be found in the subsequent subclaims.

The silane coupling agents used according to the invention exhibit the general structural formula

___ si (OR) ₃

where R * is either a terminal, reactive amino, mercapto, epoxy or vinyl group (OR) and a terminal hydrolyzable alkoxy group that is connected to the silicon atom via short alkyl chains.

The inventive improvement in the grip of the mixtures mentioned at the outset is in accordance with method described below achieved. Silicon carbide, quartz or sand with grain sizes greater than 0.01 mm and 0.5 mm are wetted with an aqueous solution or dispersion of a silane coupling agent tailored to the respective vulcanization system. In the case of a peroxide vulcanization system, the use of a vinyl silane adhesion promoter has proven to be most useful in the case of a sulfur vulcanization system, on the other hand, it is cheaper to use a mercapto silane - Proven adhesion promoter.

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Amino adhesion promoters are also suitable for this process. The even application of the silane adhesion promoter in prescribed concentrations (see application methods of Silanes from UNION CARBIDE, 1973 edition) are made by stirring the materials into the previously prepared one Solution or suspension of the silane in water. Also by spraying or other known methods a uniform coating of the surface of the grains with silane can take place. Extraction then takes place of the water under vacuum and temperatures around 100 C with simultaneous drying of the grains of these limaterialien, The grains treated in this way can then be added to the rubber mixtures in a kneader or on a roller, after which a vulcanization of approx. 10 - 120 minutes at 160 ° C and 200 atmospheres pressure takes place, which is a firmly adhering Binding of the grains in the mixture causes. The materials can either already be the mixes be added in the kneader, in order to avoid damage to the sensitive kneader elements However, it is advisable to add the grains treated in this way to the mixture in the rolling mill.

The invention is documented on the basis of the comparative tests below. Various for Tire track strips used mixtures used. Mixture A is a carbon black standard mixture, mixture B is one filled with precipitated silica Adhesive mixture with additions of 10 wt. respectively 20 Gwt. silanized silicon carbide were added. Mixtures B, B I and B II were used as tire treads Tests for their slip resistance (braking test and circle test) on "wet ice" with a surface temperature lying around 0 C and dry

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Subjected to ice and brake line on wet road. Tires of size 175 SR 14 were used. Mixtures A I and A II did not become treads processed, since it was found that the added silicon carbide in spite of the silane treatment Bond in the mixture, but fell out immediately under dynamic alternating stress. In the adhesive mix B, despite extreme alternating stresses, the silanized silicon carbide grains did not dissolve on.

Mixture A

Polybutadiene rubber Styrene butadiene rubber Highly abrasion-resistant furnace black Precipitated silica chalk, mineral oil softener, anti-aging agent, zinc oxide

Stearic acid

Diphenylguanidine sulfenamide accelerator Tetramethylthiuram monosulfide sulfur

Triethoxisilane derivative

Gwt
50
50
85

0
35

0.1

1.6

Gwt

70

30th

120

70 3 4 1

2.8 1.2 0.1 2.0 6

Investigation results ;

Mixture B
Mixture B I Mixture B II

Mixture B Mixture B I Mixture B II

Anti-slip resistance Brake test wet ice dry ice 100% 100 % 113 % 110 % 121 % 118 % Slip resistance Circle test 100 % 100 % 129 % 106 % 136 % 110 %

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Brake test on a wet road

B. I. from 40 km / h from 60 km / h from 80 km / h mixture B. II 100 % 100 1 100% mixture B. 107% 105 5 & 104 % mixture 113 % 112? 109%

In summary, the test results show that that the adhesive mixture known to be better than the standard mixtures / through the addition of the silanized silicon carbide can still be improved considerably. In all exams specifically based on practice If these new compounds are aligned with one another, they perform and perform much better with tires used to create a competitor of equal value to spike tires, especially on wet ice. The method according to the invention is not only applicable to the improvement of mixtures for tire treads limited, but can still be used in the manufacture of such products which hard particles have to be embedded and adhered to a carrier material. For example, with braking and clutch linings, grinding disks and grinding tools of various types.

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Claims (5)

PATENT CLAIMS ll. Improve grip from optional Natural rubber, polyisoprene, styrene butadiene rubber, polybutadiene rubber, ethylene - propylene - ter - polymer rubber, Nitryl butadiene rubber and silicone rubber produced mixtures on dry and wet Road surface and on dry and wet ice, especially for tire treads or shoe soles, whereby these mixtures contain reinforcing fillers in addition to the usual vulcanization auxiliaries and with sulfur or peroxides are vulcanized, characterized by g e, that the mixtures as reinforcing filler 10-150 parts by weight of silica in precipitated form alone or in combination with 0.100 Parts by weight of carbon black and 5-50 parts by weight of one with a monomeric silane coupling agent of the general structure si - (OR) pretreated silicon carbide, quartz sand or in grain sizes above 0.01 mm, preferably 0.01 mm between O and containing from ₁ to 5 mm. 609824/0121 2. Process for improving the mixtures according to claim 1, characterized that the silane coupling agent with water to form an aqueous solution or dispersion is hydrolyzed that then the silicon carbide, the sand or quartz treated with it, preferably is washed or sprayed, whereupon the water is removed again in vacuo and at temperatures around 100 ° C or is evaporated and the silanized silicon carbide, the sand or the quartz then either with the raw mixture components mixed or an already vulcanized or prepolymerized Mixture is added and processed with it and vulcanized. 3. The method according to the preceding claims, in particular for improving peroxidically crosslinked Mixtures, characterized in that the silicon carbide, the sand or the quartz prior to admixture with a vinyl silane - Adhesion promoter is treated. 4. Process for improving mixtures according to Claims 1 and 2 with regard to their grip on ice and snow, characterized that the silicon carbide, the sand or the quartz before being mixed with an aminosilane - Adhesion promoter is treated. 0 9 8 2 4/0121 5. Method for improving rubber compounds vulcanized with sulfur, thereby characterized in that the silicon carbide, the sand or the quartz prior to admixture treated with a mercapto-silane coupling agent. 609824/01 21