ES2380323T3 - Silicon precipitation acid with a high specific surface area - Google Patents

Abstract

Precipitated silica (I) has the following characteristics: BET surface area of 200-300 m2/g; CTAB surface area at least 170 m2/g; DBP-number 200-300 g/(100 g); Sears number V2 23-35 ml/(5 g). Independent claims are also included for the following: (1) preparation of (I); (2) elastomeric mixtures, vulcanized rubber mixtures and/or vulcanizates containing (I) as above; (3) tires, tires for commercial vehicles, tires for motor cycles, tires for high speed commercial vehicles, all containing (I) as above.

Description

Silicon precipitation acid with a high specific surface area.

The present invention relates to a highly dispersed precipitation silicic acid, which has a high specific surface area, a process for its preparation and its use as a loading material for covers (of 5 tires) of useful motor vehicles, motorcycles and motor vehicles. for high speeds.

The use of precipitation silicic acids in mixtures of elastomers, such as those used for roofs, has long been known. For silicic acids, which are used in roofs, high requirements are raised. They must be dispersible in the rubber with ease and in a good way, they must form a good bond with the polymer chains contained in the rubber or respectively with the other materials of 10 load and must have a high resistance to abrasion, similar to that of carbon blacks. Alongside the dispersibility of silicic acid, therefore, among other properties, specific surfaces (according to BET or CTAB) and oil absorption capacity (DBP) are important. The surface properties of silicic acids decisively determine their possible use, or respectively certain uses of a silicic acid (eg those of as support systems or fillers for elastomer blends) require certain

15 surface properties.

Thus, the US patent document. US 6013234 discloses the preparation of a precipitation silicic acid with surfaces according to BET and CTAB in each case of 100 to 350 m2 / g. This silicic acid is especially suitable for incorporation into elastomer mixtures, with the BET / CTAB ratios between 1 and 1.5. In European patent document EP 0937755 different precipitation silicic acids are disclosed, which have a surface area according to BET of from about 180 to about 430 m2 / g and a surface area according to CTAB of about 160 to 340 m2 / g. These silicic acids are especially suitable as a support material and have a BET to CTAB ratio of 1.1 to 1.3. EP 0647591 discloses a precipitation silicic acid, which has a surface ratio according to BET to the surface according to CTAB of 0.8 to 1.1, these surface characteristics being able to adopt absolute values up to 350 m2 / g. At

EP 0643015 presents a precipitation silicic acid, which can be used as an abrasive and / or thickening component in toothpastes, which has a surface area according to BET of 10 to 130 m2 / g and a surface area according to CTAB of 10 to 70 m2 / g, that is, a ratio of BET to CTAB of approximately 1 to 5.21.

Certain silicic acids, which are especially suitable as fillers for elastomer blends, here in particular for PKW shells, are described in EP 0901986 with the following properties:

Surface according to BET 120 - 300 m2 / g Surface according to CTAB 100 - 300 m2 / g Ratio of BET / CTAB 0.8 - 1.3 Number of Sears V2 (0.1 N NaOH consumption) 6 - 25 ml / (5 g) DBP index 150 - 300 g / (100 g) WK coefficient <3.4 Particle size of decomposed particles <1.0 μm Particle size of non-decomposed particles 1.0 - 100 μm

EP 0983966 discloses precipitation silicic acids with an Al2O3 content of 0.2 to 5.0% by weight, a WK coefficient of less than 3.4 and a Sears number of 5-25 ml. All precipitation silicic acids in the Examples have a Sears number manifestly below 25 ml.

For automobile vehicle covers, very different requirements are established, depending on the purpose of employment. In the case of a subdivision, it is enough to cover PKW and LKW, at least the following differences must be taken into account:

Requirement for PKW covers (indicative values)

Requirement for LKW covers (indicative values)

Main component of the tread

Mixtures of E- and L-SBR with BR An NR, partially as a mixture with a BR

Possibility of retreading

It's not important at least 3 times

Rolling performance

40,000 km in Europe 64,000 km in the US 3 x 200,000 km

Maximum speed

160 - 240 km / h and higher 100 km / h (maximum 140 km / h)

Filling pressure

2.2 bar 8.5 bar

Support capacity per axle

1,000 kg 6,300 kg (simple equipment with covers)

Off-road use

 small tall

Heat build-up (Heat Build Up)

little  very important

Rolling resistance

very important Important

Tensile strength

little Important

The PKW within the meaning of the present invention are motor vehicles (= passenger cars) for the transport of people for predominantly private use, that is to say that it is not a useful motor vehicle such

5 as eg delivery vehicles. Within this concept, some motor vehicles do not enter, which are usually operated at high speeds, even though these, according to their constructive type, can serve as PKW. These motor vehicles also have other requirements for covers, which are different than for the PKW covers mentioned in the Table.

The covers for motorcycles and for PKW with high speeds must also have very high degrees of

10 load in the case of high speeds and a very good behavior of dry and wet slipping (traction). Good traction, however, should not be linked to increased abrasion or, respectively, high rolling resistance.

The different requirements of motor vehicles in terms of tires have corresponding repercussions on the load materials used in the tires. The addition of silicic acids and organic silicon compounds as a system of fillers, which has been enshrined in PKW roofs for a long time, leads to reduced rolling resistance, improved traction behavior and reduced performance. abrasion. A transfer of these improved properties to covers for useful motor vehicles, such as LKW (trucks), would be desirable, since with a reduced rolling resistance a smaller fuel consumption is linked. The different requirements of those mentioned

20 motor vehicles in terms of their covers, however, necessarily lead to different requirements for the cargo materials used.

It has been shown that the silicic acids used for PKW decks are inappropriate for use on LKW decks, motorcycle decks and high speed decks for PKW because of the different requirements profile. A mission of the present invention was, therefore, to make available silicic acids of precipitation with a property profile that is specially adapted to these motor vehicles. It is known to a person skilled in the art that, in the case of the use of active carbon blacks as a loading material for roofs, with an elevation of the specific surface an improvement of the reinforcement and consequently of the abrasion resistance is achieved Of the cover. The use of carbon blacks with high specific surfaces (surface area according to CTAB> 130 m2 / g) is limited, however, due to the accumulation of strongly increasing heat (hysteresis behavior, described and measurable according to DIN standard 53535,

or respectively according to the references mentioned in this DIN standard) in mixtures filled with fillers in this way.

It was finally found that a precipitation silicic acid, which has a high surface area according to CTAB, is especially suitable as a loading material in elastomer blends for equipment with roofs

35 useful motor vehicles, for motorcycle covers and for PKW tires for high speeds.

The subject of the present invention, therefore, is silicic acid precipitation with a surface area according to BET of 200-300 m2 / g, a surface area according to CTAB of; 170 m2 / g, a DBP index of 200-300 g / (100 g) and a Sears V2 number of 23-35 ml / (5 g).

40 Because of the manifestly diminished hysteresis in the case of the use of a silicic acid according to the invention as a filler material, specific surfaces can therefore be produced, which in the

case of a carbon black are prohibited because of the highest hysteresis, and in this way lead to a improvement of abrasion resistance.

The precipitation silicic acids according to the invention may have a maximum surface area according to CTAB of 300 m2 / g, in particular an area according to CTAB of 170 - 220 m2 / g or 245 - 300 m2 / g.

The precipitation silicic acids according to the invention may in each case independently have properties located within the following preferred ranges: DBP absorption 230 - 300 g / (100 g), in particular 230 - 280 g / (100 g) WK coefficient: 3.4, preferably: 3.0, in particular: 2.5 Number of Sears V2 26 - 35 ml / (5 g)

The WK coefficient is defined as the ratio of the peak height of the non-decomposable particles by ultrasound in the size range of 1.0 - 100 μm at the peak height of the decomposed particles in the size region <1.0 μm (see Fig. 1).

EP 1186629 discloses silicic acids with high surfaces according to CTAB, which are appropriate as loading material for roofs. Data on the number cannot be deduced from EP 1186629 of Sears nor, respectively, about the concentration of hydroxy groups next to the surface of the silicic acid

A further object of the present invention is a process for the preparation of a silicic acid of

precipitation with a surface according to BET 200 - 300 m2 / g an area according to CTAB; 170 m2 / g a DBP index 200 - 300 g / (100 g) a number of Sears V2 23 - 35 ml / (5 g)

realizing that a) an aqueous solution of an alkali metal or alkaline earth metal silicate and / or an organic and / or inorganic base with a pH is previously available; 9,

b) in this preload, dosing is introduced with stirring at 55-95 ° C for 10-120, preferably for 10-60 minutes, at the same time a soluble glass and an acidifying agent,

e) with sulfuric acid it is acidified to a pH value of approximately 3.5 and f) is filtered and dried.

The precipitation silicic acid prepared according to the invention may have properties included in said preferred ranges:

The preload can be approximately 20, 30, 40, 50, 60, 70, 80 or 90% of the final volume of the precipitate. The added basic compounds are chosen in particular from the set of alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkali metal hydrogen carbonates and alkali metal silicates. Preferably, a soluble glass or a solution of sodium hydroxide (= sodium hydroxide solution) is used. The pH value of the preload is set to; 9, preferably between 9.0 and 12, especially between 9 and 10.5. It is possible to use a previous charge with nothing or only a small amount of an electrolyte (salt) and add the electrolytes in a continuous or discontinuous manner (preferably at the beginning of the precipitation).

Optionally, the process according to the invention may have a stop point. In this case, between steps b) and e) steps c) of stopping the metered addition for 30-90 minutes are carried out while maintaining temperature maintenance and d) at the same time adding a soluble glass and a sulfuric acid, preferably an acid

sulfuric acid, at the same temperature with stirring for 20-120, preferably for 20-80 minutes.

Optionally, an additional addition of organic or inorganic salts may be carried out during steps b) and d). This can be carried out in a solution or as a solid material, in each case on a continuous basis during the period of time of the addition of the soluble glass and the sulfuric acid, preferably sulfuric acid, or as a discontinuous addition (by charges). It is also possible to dissolve the salts in one or both components and then add them at the same time as these.

As inorganic salts, alkali metal or alkaline earth metal salts are preferably used. In particular, combinations of the following ions can be used: Li +, Na +, K +, Rb +, Be2 +, Mg2 +, Ca2 +, Sr2 +, Ba2 +, H +, F-, Cl-, Br-, I-, SO32-, SO42- , HSO4-, PO33-, PO43-, NO3-, NO2-, CO32-, HCO3-, OH-, TiO32-, ZrO32-, ZrO44-, AlO2-, Al2O42-, BO43-.

As organic salts, salts of formic, acetic and propionic acids are suitable. As a cation, the aforementioned alkali or alkaline earth metal ions should be mentioned. The concentration of these salts in the preload can be from 0.01 to 5 mol / l. Preferably Na2SO4 is used as an inorganic salt. It is possible to provide the acidification agent in steps b) and d) in the same or different way, that is to say with the same or different concentrations and / or inflow rates.

Similarly, soluble glass can also be added in steps b) and d) to the reaction in an equal or different way.

In a special embodiment, in steps b) and d), the components, the acidifying agent and the soluble glass are provided such that the inflow rates in step d) are 125-140% of the inflow rates in stage b), the components being used in both stages in each case in an equimolar concentration. Preferably the components are added with the same concentration and with the same flow rate.

Together with a soluble glass (a solution of sodium silicate) other silicates such as potassium or calcium silicate can also be used. As acidification agents, other acidification agents such as HCl, HNO3, H3PO4 or CO2 can be used together with sulfuric acid.

Filtration and desiccation of the silicic acids according to the invention are common for a person skilled in the art and can be consulted eg in said documents. Preferably, the precipitation silicic acid is dried in a circulating current drying apparatus, a spray drying apparatus, a floor drying apparatus, a conveyor belt drying apparatus, a rotary tube drying apparatus, an evaporating drying apparatus sudden, a sudden rotary and evaporation dryer or a nozzle tower. These variants of desiccation include operation with an atomizer, with a nozzle for a single material or for two materials, or with an integrated fluid bed. Preferably, the precipitation silicic acid according to the invention has, after the drying stage, a particle shape with an average diameter located above 15 μm, in particular above 80 μm, particularly preferably by over 200 μm. The average diameter of the particles is defined in such a way that 50% by weight of the particles have a larger or smaller diameter.

After drying, granulation with a roller compactor can also be carried out. In this context the average diameter of the particles is located at � 1 mm.

Preferably, the silicic acid according to the invention is used in covers of useful motor vehicles LKW, PKW for high speeds and motorcycles.

As motor vehicles useful in the sense of the present invention, all motor vehicles are considered, in which high demands are established for the tires in relation to rolling performance or wear. As regards the requirement of high rolling performance, covers for buses, LKW and / or delivery vehicles as well as trailers must be mentioned in particular. As regards wear resistance such as eg tear resistance in mining galleries, Chipping (rock fragment abrasion), Chunking (very small particle corrosion detachment), should be mentioned covers for motor vehicles that circulate off-road, construction and agricultural machines, mining vehicles and tractors. In the present context, particular consideration is given to motor vehicles with an axial load (on axles) of more than 1 ton or respectively with a total permissible weight of over 2, 4, 7.5 or 15 tons. The silicic acids according to the invention can be used in particular for traction covers for heavy LKW or for their trailers. Such vehicles often have axial loads located above 5 tons or respectively a tire diameter of above 17 ‘’ (inches = 43.18 cm).

Covers for useful motor vehicles such as LKW are subdivided according to speed classes. The silicic acids according to the invention are especially suitable for covers (of LKW) which are admitted for speeds between 80 and 140 km / h and which bear the symbols F, G, J, K, L, M or N.

The covers for high-speed motor vehicles (motorcycles or PKW) are those that are supported for a speed above 180 km / h. These are the covers (of PKW) with the symbols S, T, U, H, V, W, Y and ZR.

A further object of the invention are mixtures of elastomers, mixtures of vulcanizable rubbers and / or other vulcanized materials, which contain the silicic acid according to the invention, such as for example molded bodies such as tire covers, tire treads, wrappers. cables, hoses, propulsion belts, conveyor belts, cylinder liners, covers or tires, shoe soles, sealing rings and damping elements.

In addition, the silicic acids according to the invention can be used in all sectors of use, in which silicic acids are usually used, such as e.g. in battery separating elements, as anti-caking agents, as matting agents. in paints and varnishes, as supports or vehicles for agricultural products and food, in coatings, in printing inks, in fire extinguishing powders, in synthetic materials, in the non-impact printing sector, in a mass for paper, in the personal care sector (in English personal care) and in special uses.

By use in the printing sector without impact, eg according to the inkjet process, the use of the silicic acids according to the invention should be understood.

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in printing inks for thickening or for avoiding splashes and ink transfers between overlapping sheets

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in a paper such as a filler and filler material, in a coating pigment, in a heliographic tracing paper, in a thermal paper, in the case of thermal sublimation in order to prevent the tracing or transfer of printing inks, to Improving the background stability of an image and contrast, in order to improve the sharpness of the dots and the brightness of the colors.

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By a use in the personal care sector, the use of silicic acids according to the invention should be understood as a filler and filler or thickening agent, eg in the pharmacy sector

or body wash.

Optionally, the silicic acid according to the invention can be modified with silanes or organosilanes of the formulas I through III [SiR1n (RO) r (Alk) m (Ar) p] q [B] (I), SiR1n (RO) 3-n (Alkyl) (II), or SiR1n (RO) 3-n (Alkenyl) (III),

in which they mean

B: -SCN, -SH, -Cl, -NH2, -OC (O) CHCH2, -OC (O) C (CH3) CH2 (when q = 1) or -Sw- (when q = 2), where B chemically bonded to Alk,

R and R1: an aliphatic, olefinic, aromatic or aryl aromatic radical with 2-30 C atoms, which may optionally be substituted with the following groups: a hydroxy, amino, alcoholate, cyanide, thiocyanide, halogen radical , sulfonic acid, sulfonic acid ester, thiol, benzoic acid, benzoic acid ester, carboxylic acid, carboxylic acid ester, acrylate, methacrylate, organosilane, and R and R1 may have a meaning or an equal or different substitution.

n: 0, 1 or 2, Alk: a divalent, unbranched or branched hydrocarbyl radical with 1 to 6 carbon atoms,

m: 0 or 1,

Ar: an aryl radical with 6 to 12 C atoms, preferably with 6 C atoms, which may be substituted with the following groups: a hydroxy, amino, alcoholate, cyanide, thiocyanide, halogen, radical sulfonic acid, sulfonic acid ester, thiol, benzoic acid, benzoic acid ester, carboxylic acid, carboxylic acid ester, acrylate, methacrylate, organosilane,

p: 0 or 1, with the proviso that p and n do not mean 0 at the same time,

q: 1 or 2,

w: a number from 2 to 8,

r: 1, 2 or 3, with the proviso that r + n + m + p must be = 4, Alkyl: a univalent, unbranched or branched saturated hydrocarbyl radical, with 1 to 20 carbon atoms, preferably with 2 to 8 carbon atoms,

Alkenyl: a univalent, unbranched or branched unsaturated hydrocarbyl radical having 2 to 20 carbon atoms, preferably 2 to 8 carbon atoms.

Also, the silicic acid according to the invention can be modified with organic silicon compounds having the composition SiR24-nXn (with n = 1, 2, 3), [SiR2xXyO] z (with 0: x: 2; 0: y: 2; 3: z: 10, with x + y = 2), [SiR2xXyN] z (with 0: x: 2; 0: y: 2; 3: z: 10, with x + y = 2), SiR2nXmOSiR2oXp ( with 0: n: 3; 0: m: 3; 0: o: 3; 0: p: 3, with n + m = 3, or + p = 3), SiR2nXmNSiR2oXp (with 0: n: 3; 0: m: 3; 0: o: 3; 0: p: 3, with n + m = 3, or + p = 3), SiR2nXm [SiR2xXyO] zSiR2oXp (with 0: n: 3; 0: m: 3; 0 : x: 2; 0: y: 2; 0: o: 3; 0: p: 3; 1: z: 10,000, with n + m = 3, x + y = 2, or + p = 3). In the case of these compounds, they may be linear, cyclic and branched silane, silazan and siloxane compounds. In the case of R2 it may be alkyl and / or aryl radicals with 1-20 carbon atoms, which may be substituted with functional groups such as the hydroxy group, the amino group, polyethers such as ethylene oxide and / or oxide of propylene and halide groups such as fluoride. R2 may also contain groups such as alkoxy, alkenyl, alkynyl and aryl groups, and sulfur-containing groups. In the case of X it may be reactive groups such as silanol, amino, thiol, halide, alkoxy, alkenyl and hydride groups.

Preferably, linear polysiloxanes with the composition SiR2nXm [SiR2xXyO] zSiR2oXp (with 0: n: 3;

0: m: 3; 0: x: 2; 0: y: 2; 0: o: 3; 0: p: 3; 1: z: 10,000, with n + m = 3; x + y = 2; or + p = 3), in which R2 is preferably represented by methyl.

Especially preferred are polysiloxanes of the composition SiR2nXm [SiR2xXyO] zSiR2oXp (with

0: n: 3; 0: m: 1; 0: x: 2; 0: y: 2; 0: o: 3; 0: p: 1; 1: z: 1,000, with n + m = 3, x + y = 2, or + p = 3) in which R2 is preferably represented by methyl.

Modification of precipitation silicic acids, optionally granulated, without granulation, ground and / or without grinding, with one or more of the aforementioned organosilanes can be carried out in mixtures of 0.5 to 50 parts, referred to 100 parts of the precipitation silicic acid, in particular from 1 to 15 parts, referred to 100 parts of the precipitation precipitation silicic acid, the reaction between the precipitation silicic acid and the organosilane taking place during the preparation of the mixture (in situ) or outside it, by spray application and subsequent tempering of the mixture, by mixing the organosilane and the suspension of silicic acid with a subsequent desiccation and tempering (for example, in accordance with the application documents of German patents DE 3437473 and DE 19609619) or in accordance with the procedure described in the DE 19609619 or German patent DE-PS 4004781.

As organic silicon compounds, all bifunctional silanes are suitable, which they can make, on the one hand, a coupling with the loading material containing silanoles groups and, on the other part, a coupling with the polymer. Usual used amounts of organic silicon compounds they are from 1 to 10% by weight, based on the total amount of precipitation silicic acid.

Examples of these organic silicon compounds are: Bis (3-triethoxy-silyl-propyl) -tetrasulfan, bis (3-triethoxy-silyl-propyl) disulfan, vinyl-trimethoxy-silane, vinyl-triethoxy-silane, 3-mercapto-propyl-trimethoxy-silane, 3-mercapto-propyl-triethoxy-silane, 3-amino-propyl-trimethoxy-silane and 3-amino-propyltriethoxy-silane. Other organic silicon compounds are described in the patent application document WO 99/09036 and in EP 1108231, DE 10137809, DE 10163945 and DE 10223658.

In a preferred embodiment of the invention, bis (triethoxy-silyl-propyl) tetrasulfan can be used as silane.

The silicic acid according to the invention can be incorporated into mixtures of elastomers, covers or mixtures of Vulcanizable rubbers, as reinforcing filler material in quantities of 5 to 200 parts, referred to 100 parts of a rubber, in the form of a powder, of a spherical shaped product or of a granulate, both with a Modification by silanes as well as without any modification by silanes. Mixtures of rubbers and elastomers should be considered as equivalent in the sense of the present. invention.

Together with mixtures, which exclusively contain silicic acids compliant as fillers invention, with and without the aforementioned organosilanes, mixtures of elastomers or rubbers may be filled additionally with one or several more or less reinforcing fillers. As other loading materials, the following materials can be used:

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Carbon blacks: Carbon blacks usable in this case are produced according to the flame carbon, furnace or gas black process and have surfaces according to BET of 20 to 200 m2 / g, such as p. eg carbon blacks from SAF, ISAF, HSAF, HAF, FEF or GPF. Carbon blacks may also eventually contain heteroatoms such as silicon.

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Highly dispersed pyrogenic silicic acids, prepared for example by flame hydrolysis of silicon halides. Silicon acids may also eventually be present as mixed oxides with other metal oxides, such as the oxides of Al, Mg, Ca, Ba, Zn and titanium,

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other commercial silicic acids,

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synthetic silicates, such as aluminum silicate, alkaline earth metal silicates, such as magnesium silicate or calcium silicate, with surfaces according to BET of 20 to 400 m2 / g and primary particle diameters of 10 to 400 nm,

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synthetic or natural aluminum oxides and hydroxides,

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natural silicates, such as kaolin and other silicon dioxide compounds present in nature,

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glass fibers and glass fiber products (mats, cords) or glass microspheres,

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starches and types of modified starches,

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natural fillers, such as for example clays and silica clay.

The mixing ratio is also adjusted in the present case, as in the case of the dosed addition of the organosilanes, to the table of properties to be obtained from the finished vulcanized rubber mixture. A ratio of 5-95% between the silicic acids according to the invention and the other fillers mentioned above (also in the form of a mixture) is conceivable and is also carried out within this framework.

In a particularly preferred embodiment, mixtures of 10 to 150 parts by weight of silicic acids, which are composed wholly or partially of the silicic acids according to the invention, may be used together with 0 to 100 parts. by weight of a carbon black, as well as 1 to 10 parts by weight of an organic silicon compound, in each case referred to 100 parts by weight of a rubber.

Together with the silicic acids according to the invention, organosilanes and other fillers, elastomers constitute another important additional component of the rubber mixture. Mention should be made in this context of elastomers, natural or synthetic, extended or not in oil, as an individual polymer or as a mixture prepared (in English blend) with other rubbers, such as for example natural rubbers, a polybutadiene (BR), a polyisoprene (IR), styrene and butadiene copolymers with styrene contents of 1 to 60, preferably 2 to 50% by weight (SBR), in particular prepared by the solution polymerization process, butyl rubbers, copolymers of isobutylene and isoprene (IIR), copolymers of butadiene and acrylonitrile with acrylonitrile contents of 5 to 60, preferably 10 to 50% by weight (NBR), a partially hydrogenated or fully hydrogenated NBR rubber (HNBR), copolymers of ethylene, propylene and a diene (EPDM), as well as mixtures of these rubbers. In addition, for mixtures of rubbers with the aforementioned rubbers, the following additional rubbers come into question: carboxylic rubbers, epoxy rubbers, trans-polyphenanthomers, halogenated butyl rubbers, rubbers based on 2-chloro-butadiene, copolymers of ethylene and vinyl acetate, copolymers of ethylene and propylene, possibly also chemical derivatives of natural rubber as well as modified natural rubbers. Preferred synthetic rubbers are described, for example, in the work of W. Hofmann, "Kautschuktechnologie", (rubber technology), Genter publishing house, Stuttgart 1980. For the production of the covers according to the invention, rubbers are of particular interest L-SBR (SBR in solution) anionically polymerized with a glass transition temperature above -50 ° C, as well as its mixtures with rubbers of dienes.

The silicic acids according to the invention, with or without a silane, can find use in all uses of vulcanized rubbers, such as for example molded bodies, covers, tread surfaces of covers, conveyor belts, conveyor belts, seals, propeller belts, hoses, shoe soles, cable wraps, cylinder liners, damping elements, etc.

The incorporation of this silicic acid and the preparation of the mixtures containing this silicic acid are carried out in the manner that is usual in the vulcanized rubbers industry, in an internal mixer or in a laminating device preferably at 80-200 ° C. The form of presentation and use of silicic acids, respectively, can be carried out either in the form of a powder, a spherical product or a granulate. Also in this case, the silicic acids according to the invention do not differ from the known clear fillers.

The vulcanized materials of rubbers according to the invention may contain other auxiliary substances for rubbers in the usual dosages, such as reaction accelerating agents, aging protective agents, heat stabilizing agents, photoprotective agents, ozone protective agents, agents processing aids, plasticizing agents, adhesion conferring agents (tackifier), propellant or expansion agents, colorants, pigments, waxes, extender agents, organic acids, retarding agents, metal oxides as well as activating agents, such as triethanolamine, a poly (ethylene glycol) or hexanotriol. These compounds are known in the rubbers industry.

Rubbing agents can be used in known quantities, which are oriented, among other things, to the purpose of use. Usual amounts are, for example, proportions of 0.1 to 50% by weight, based on rubber. As crosslinking agents, sulfur or sulfur donor substances can be used. Mixtures of rubbers according to the invention may contain, in addition to this, vulcanization accelerating agents. Examples of suitable major accelerating agents are mercaptobenzothiazoles, sulfenamides, thiurames or dithiocarbamates in proportions of 0.5 to 3% by weight. Examples of concomitant accelerating agents are guanidia, thioureas and thiocarbonates in proportions of 0.5 to 5% by weight. Sulfur can usually be used in proportions of 0.1 to 10% by weight, preferably 1 to 3% by weight, based on rubber.

The silicic acids according to the invention can be used in rubbers, which are crosslinkable with accelerating agents and / or with sulfur, but also with peroxides.

Vulcanization of the mixtures of rubbers according to the invention can be carried out at temperatures of 100 to 200 ° C, preferably 130 to 180 ° C, possibly under a pressure of 10 to 200 bar. The mixing of the rubbers with the filler material, possibly with the rubbing agents and with the organic silicon compound can be carried out in known mixing equipment, such as cylinder mixers, internal mixers and mixing extruders.

Silicon acids with a high specific surface area, highly dispersible according to the invention, have the advantage that they give vulcanized rubber materials an improved abrasion resistance due to the higher surface area according to CTAB. In addition, dry handling is improved because of the highest dynamic stiffness at 0 ° C and 60 ° C and rolling resistance, indicated by the decreased value of tan 8 (60 ° C). By analogy to carbon blacks, in English Carbon Blacks, in the case of the use of these silicic acids with high specific surface area, highly dispersible, according to the invention, an improved behavior of Cut & Chip and Chunking is achieved (for definition and other explanations see the work: "New insights into the tear mechanism" and the references cited here, presented at Tire Tech 2003 in Hamburg by Dr. W. Niedermeier).

The rubber mixture according to the invention is particularly suitable for the production of tire treads with a lower and improved rolling resistance, improved wet skid resistance, improved dry properties and good resistance to abrasion compared to the same rubber mixture with silicic acids known until now. These tread mixes are especially suitable for high-speed PKW tires and motorcycles, but also covers for useful vehicles with reduced rolling resistance along with good abrasion resistance and improved Cut & Chip behavior. and chunking.

In addition, the silicic acids according to the invention, without the addition of organic silicon compounds, in the mixture prepared with a typical carbon black for rolling surfaces, are also suitable for the improvement of the Cut & Chip behavior of machine covers of construction, agricultural and mining.

For the achievement of a good table of values in a polymer mixture, the dispersion of the precipitation silicic acid in the matrix, that is to say in the polymer, is of decisive importance. This can be estimated using the WK coefficient.

Fig. 1 is a schematic representation of the values necessary for the calculation of the WK coefficient.

The curves show, in the range around 1.0 - 100 μm, a first maximum in the particle size distribution and in the region of <1.0 μm show another additional maximum. The peak in the range of 1.0-100 μm indicates the proportion of the particles of silicon acid not shredded after ultrasonic treatment. These very thick particles are poorly dispersed in rubber mixtures. The second peak with manifestly smaller particle sizes (<1.0 μm) indicates that part of the silicic acid particles, which has been shredded during the ultrasonic treatment. These very small particles disperse excellently in rubber mixtures.

The WK coefficient is, now, the ratio of the peak height of the non-decomposable particles (B), whose maximum is in the range of 1.0 - 100 μm (B '), at the peak height of the decomposed particles (A), whose maximum is located in the region <1.0 μm (A ').

The WK coefficient is therefore a measure of the "decomposibility" (= dispersibility) of precipitation silicic acid. The fact that a precipitation silicic acid is dispersible with greater ease is valid, the lower the WK coefficient, that is, the more particles that have been decomposed upon incorporation into a rubber.

The silicic acids according to the invention have WK coefficients: 3.4, preferably: 3.0, especially preferably: 2.5. The known precipitating silicone acids have other WK coefficients and other different maximums in the particle size distributions, measured with the Coulter LS 230, and therefore are less dispersible.

The physical and chemical data of the precipitation silicic acids according to the invention are determined by the following methods:

Determination of moisture of silicic acids

In accordance with this method, based on ISO 787-2, the volatile portions (hereinafter referred to as moisture for reasons of simplicity) of a silicic acid after drying for 2 hours at 105 ° C are determined. This loss by desiccation is generally composed predominantly of water moisture.

Realization

In a glass for dry weighing with a frosted lid (diameter 8 cm, height 3 cm), 10 g of powdered, spherical or granular silicic acid (weighing inlet E) are weighed and introduced with an accuracy of 0.1 mg. The sample, when the lid is open, is dried for 2 h at 105 ± 2 ° C in a drying cabinet. Next, the weighing vessel is closed and cooled in a drying cabinet with silica gel as a drying agent at room temperature. The output weighing A is determined gravimetrically.

The humidity is determined in% according to ((E in g - A in g) * 100%) / (E in g).

Determination of the number of modified Sears of silicic acids

By valuing a silicic acid with a solution of potassium hydroxide in the range from pH 6 to pH 9, the number of modified Sears (hereinafter referred to as the number of Sears V2) can be determined as a measure of the number of free hydroxy groups .

The following chemical reactions serve as the basis for the determination method, and must symbolize "Si" -OH a silanol group of silicic acid: "Yes" -OH + NaCl � "Yes" -ONa + HCl HCl + KOH � KCl + H2O.

Realization

10.00 g of a pulverulent, spherical or granular silicic acid with 5 ± 1% moisture is shredded for 60 seconds with an IKA M 20 universal mill (550 W; 20,000 rpm = revolutions per minute). Eventually, the moisture content of the starting substance should be adjusted by drying at 105 ° C in a drying cabinet or by uniform wetting, and the shredding should be repeated. 2.50 g of the silicic acid treated in this way is weighed and placed at room temperature in a 250 ml capacity titration vessel, and combined with 60.0 ml of methanol p. A. (= analytically pure). After a total wetting of the sample, 40.0 ml of deionized water are added and dispersed by means of an Ultra Turrax T 25 agitator (with a KV-18G shaker, diameter 18 mm) for 30 seconds with a number of revolutions of 18,000 rpm With 100 ml of deionized water, the sample particles are rinsed in the suspension, which are adhered to the edge of the vessel and the agitator, and are tempered at 25 ° C in a thermostatically regulated water bath.

The pH measuring device (from the Knick entity, type: 766 pH-Meter Calimatic with a temperature sensor) and the pH electrode (single rod measuring chain from the Schott entity, type N7680) are calibrated to the ambient temperature mediating the use of buffer solutions (pH 7.00 and 9.00). With the pH measuring device, the starting value of the pH of the suspension is measured first at 25 ° C and thereafter, depending on the result, with a solution of potassium hydroxide (0.1 mol / l) or respectively with a hydrochloric acid solution (0.1 mol / l), the pH value is adjusted to 6.00. The consumption of the solution of KOH or respectively of HCl in ml until reaching a pH of 6.00 corresponds to V1 ’.

After this, 20.0 ml of a solution of sodium chloride (250.00 g of NaCl p. A. completed up to 1 l with deionized water) are dosed. With 0.1 mol / l of KOH, the titration is then continued until the pH value of 9.00 is reached. The consumption of the KOH solution in ml until reaching a pH of 9.00 corresponds to V2 ’.

Next, the volumes V1 'and respectively V2' are first normalized for the theoretical input weighing of 1 g and are extended with 5, from which V1 and the number of Sears V2 in the ml / units are established (5 g ).

Surface determination according to BET

The specific surface area with nitrogen (hereinafter referred to as the BET surface) of the pulverulent, spherical or granular silicic acid is determined in accordance with ISO 5794-1 / Annex D with a AREA-meter area meter (from Ströhlein entity , JUWE).

Surface determination according to CTAB

The method is based on the adsorption of CTAB (N-hexadecyl-N, N, N-trimethyl-ammonium bromide) next to the “external” surface of the silicic acid, which is also designated as “effective surface for rubber” based on ASTM 3765, or NFT 45-007 respectively (chapter 5.12.1.3). The adsorption of CTAB is carried out in an aqueous solution mediating agitation and ultrasonic treatment. The non-adsorbed CTAB, in excess, is determined by retrovaluation with NDSS (sodium dioctyl sulphosuccinate solution, “Aerosol OT” solution) with a Titroprozessor (titration processor), the end point being given by the maximum cloudiness of the solution and being determined with a phototrode (Phototrode). The temperature during all operations carried out is 23-25 ° C, in order to prevent the separation of CTAB by crystallization. The feedback is based on

Apparatus:

The Titroprozessor METTLER Toledo type DL 55 and the Titroprozessor METTLER Toledo type DL 70, equipped in each case with: a pH electrode, product manufactured by Mettler, type DG 111, and a phototrode, product manufactured by Mettler, type DP 550

A glass for evaluation, with a capacity of 100 ml, based on a polypropylene A glass container for evaluation, with a capacity of 150 ml, fitted with a lid A pressure filtration apparatus, with a capacity of 100 ml A membrane filter based on cellulose nitrate, pore size 0.1 μm, diameter Ø 47 mm, eg Whatman (order no. 7181-004)

Reagents

The CTAB (0.015 mol / l in deionized water) and NDSS (0.00423 mol / l in deionized water) solutions are purchased in a state ready for use (from Kraft, Duisburg: Custom Order No. 6056.4700 CTAB solution 0.015 mol / l; custom number 6057.4700 NDSS solution 0.00423 mol / l), stored at 25 ºC and consumed within one month.

Realization

Blind Rating

The consumption of an NDSS solution for the 5 ml titration of a CTAB solution must be checked 1 x (once) per day before each series of measurements. For this, the phototrode, before the start of the assessment, is adjusted to 1,000 ± 20 mV (corresponding to 100% transparency).

Exactly 5.00 ml of a CTAB solution is introduced into a glass for titration with a pipette and 50.0 ml of deionized water are added thereto. With stirring, the evaluation with an NDSS solution is carried out in accordance with the measurement method that is customary for the expert in the specialty, with the Titroprozessor DL 55, until reaching the maximum cloudiness of the solution. The V1 consumption of an NDSS solution in ml is determined. Each assessment must be carried out as a triplicate determination.

Adsorption

10.0 g of the powdered, spherical or granulated silicic acid with a moisture content of 5 ± 2% (if necessary the humidity is adjusted by drying at 105 ° C in a drying cabinet or by uniform wetting) they crumble for 30 seconds with a mill (from the Krups entity, model KM 75, article number 2030-70). Exactly 500.0 mg of the shredded sample is transferred to a titration vessel with a capacity of 150 ml, provided with a magnetic stirring rod, and 100.0 ml of a CTAB solution is accurately dosed. The titration vessel is closed with a lid and stirred for 15 minutes with a magnetic stirrer. The hydrophobic silicic acids are stirred with an Ultra Turrax T 25 stirrer (with a KV-18G stirring shaft, diameter 18 mm) at a maximum of 18,000 rpm for 1 min until total wetting. The titration vessel is screwed to the Titroprozessor DL 70 and the pH value of the suspension is adjusted with KOH (0.1 mol / l) to a value of 9 ± 0.05. An ultrasonic treatment is carried out for 4 minutes of the suspension in the vessel for evaluation in an ultrasonic bath (from the Bandelin entity, Sonorex RK 106 S, 35 kHz) at 25 ° C. An immediate pressure filtration is then carried out through a membrane filter with a nitrogen pressure of 1.2 bar. The previous 5 ml fraction is discarded.

Assessment

5.00 ml of the remaining filtered material is introduced with a pipette into a vessel for titration with a capacity of 100 ml and up to 50.00 ml is completed with deionized water. The titration vessel is screwed to the DL 55 Titroprozessor and with stirring the titration is carried out with an NDSS solution until it reaches maximum cloudiness. Consumption VII of the NDSS solution in ml is determined. Each cloudiness must be performed as a triplicate determination.

Calculation

With the help of the measured values of VI = consumption of the NDSS solution in ml when evaluating the sample blindly VII = consumption of the NDSS solution in ml when the filtrate is used result: VI / VII = quantity of CTAB material of the blind sample / quantity of CTAB material still present in the sample Sample of the filtered material. From this it follows for the adsorbed amount of material N of CTAB in g: N = ((VI - VII) * 5.5 g * 5 ml) / (VI * 1,000 ml). Since only 5 ml of 100 ml of the filtrate were titrated, 0.5 g of a silicic acid with a defined humidity, and the space occupation of 1 g of CTAB is 578435 * 10-3 m2, they are deduced from it: The surface area according to CTAB (not corrected by water) in m2 / g = (N * 20 * 578,435 m2 / g) / (0.5 g) and the surface area according to CTAB (not corrected by water) in m2 / g = ((VI - VII) * 636,2785 m2 / g) / VI. The surface according to CTAB is referred to anhydrous silicic acid, whereby the following correction is carried out. Area according to CTAB in m2 / g = (area according to CTAB (not corrected by water) in m2 / g * 100%) / (100% - humidity in%)

DBP absorption determination

The absorption of DBP (DBP index), which is a measure of the absorption capacity of precipitation silicic acid, is determined, based on DIN 53601, as follows:

Realization

12.50 g of a powdered or spherical silicic acid having a moisture content of 0-10% (if necessary the moisture content is adjusted by drying at 105 ° C in the drying cabinet) are added to the kneader chamber (article No. 279061) of the Absorptometer (absorption measuring device) of Brabender “E”. In the case of granules, the granulometric fraction of 3.15 to 1 mm is used (with stainless steel sieves of the Retsch entity) (by gentle compression on the granules with a spatula of synthetic material through the sieve with a width of pores of 3.15 mm). Mediating constant mixing (with a rotation speed of the kneading paddles of 125 rpm) is added dropwise at room temperature, through the device "Dosimaten Brabender T 90/50", dibutyl phthalate (= DBP) with a speed of 4 ml / min, to the mixture. The introduction and mixing are carried out with only a small power consumption and monitored with the help of the digital display. Towards the end of the determination, the mixture becomes pasty, which is indicated by a sharp rise in force consumption. In the case of an indication of 600 digits (torque of 0.6 Nm) by means of an electrical contact, both the mixer and the dosed addition of DBP are disconnected. The synchronous motor for DBP input is coupled with a digital counter device, so that the consumption of DBP in ml can be read.

Assessment

The absorption of DBP is indicated in g / (100 g) and is calculated using the following formula based on consumption DBP measured. The density of DBP is at 20 ° C typically 1.047 g / ml. DBP Absorption in g / (100 g) = ((DBP consumption in ml) * (DBP density in g / ml) * 100) / (12.5 g) DBP absorption is defined for dried anhydrous silicic acid. In the case of the use of silicic acids of wet precipitation, the value has to be corrected by the following Corrections Table. The value corrected corresponding to the water content, it is added with the experimentally determined DBP value; eg a water content of 5.8% would mean an addition of 33 g / (100 g) for DBP absorption.

Correction table for dibutyl phthalate absorption - anhydrous Determination of the WK coefficient: size distribution of the conglomerates by laser diffraction

% of water

Water% 0.0 0.2 0.4 0.6 0.8

0

0

2 4 5 7

one

9 10 12  13  fifteen

2

16  18  19 twenty 22

3 4 5 6 7 8 9 10

2. 3  24  26 27 28

28

 29  29 30 31

31

 32  32 33 33

3. 4

 3. 4  35 35 36

36

 37  38 38 39

39

 40  40 41 41

42

 43  43 44 44

Four. Five

 Four. Five  46 46 47

5 Previous sample preparation

If, in the case of the silicic acid to be measured, it is a question of granules, then 5 g of the granular silicic acid are added to a beaker and the coarse grain granules are crushed with a hand of syrup but not Crush with a mortar. 1.00 g of shredded, powdered or spherical silicic acid

10 with a moisture content of 5 ± 1% (if necessary, the moisture content is adjusted by drying at 105 ° C in the drying cabinet or by uniform wetting), the preparation of which occurred at most 10 days ago, is weighed and introduced into a centrifuge vessel that has a capacity of 30 ml, with a domed bottom (height 7 cm, Ø 3 cm, depth of convex bulge 1 cm) and is completed with deionized water up to

1,000 ml with 20.0 ml of a dispersion solution (hydrophilic silicic acids: 20.0 g of sodium hexametaphosphate

15 (from the Baker entity) completed with deionized water up to 1,000 ml; hydrophobic silicic acids: 200.0 ml of ethanol p. A. With 2.0 ml of a 25% solution of ammonia and 0.50 g of Triton X-100 (from the Merck entity), complete with deionized water up to 1,000 ml). Next, the centrifuge vessel is placed inside a double-walled glass container for cooling (capacity 80 ml, height 9 cm, Ø 3.4 cm) with connections with cooling water for running water (at 20 ° C ) and the sample is treated for 270 s (seconds)

20 with an ultrasonic finger (from the Bandelin entity, type UW 2200 with Horn DH 13 G and a Ø 13 mm diamond plate). For this, next to the network part (Sonopuls, of the Bandelin entity, type HD 2200) of the ultrasonic finger, 50% of power and 80% of impulse (corresponding to a power of 0.8 s and a pause) are set. 0.2 s). Water cooling guarantees a suspension heating of a maximum of 8 ° C. Until the addition of the samples to the liquid module of the laser diffraction apparatus is carried out in the

After 15 min, the suspension is stirred with a magnetic stirrer in order to avoid eventual settling.

Realization

30 Before the start of the measurement, the LS 230 X-ray diffraction apparatus (from the Coulter entity) and the liquid module (LS Variable Speed Fluid Module Plus with an integrated CV 181 ultrasonic finger) are operated hot for 2 hours , from the Coulter entity) and the module is rinsed (“regulation / rinse” menu strip) for 10 min. The file window "calculate the opt model" is selected via the menu item "Software" in the logic program (Software) control strip and the refractive index is set in a file

35 .rfd as follows: �? Refractive index of liquid B.I. Real = 1,332; Refractive index of Real material = 1.46; Imaginary = 0.1. In the “measurement cycle” file window, the pumping speed power is set to 26% and the ultrasonic power of the integrated CV 181 ultrasonic finger is adjusted to 3. The ultrasound points “during the addition of the samples test ”,“ 10 seconds before each measurement ”and“ during the measurement ”must be activated. Additionally, the following points are chosen in this file window:

40 offset measurement, adjustment, background measurement, adjustment of the measured concentration, introduction of the test sample information, introduction of the sample information, introduction of the measurement information, start of 2 measurements, automatic rinse , With PIDS Data. After the calibration measurement has been completed with a size control pattern (LS Size Control G15 Standard of the Coulter entity) and the background measurement, the samples are added. Is added of

In this way a silicic acid suspended for so long until a light absorption of 45-55% has been reached and the apparatus warns "OK" (conforming). The measurement is made at room temperature with the evaluation model of the .rfd file set out above. For each sample of silicic acid, three duplicate determinations are carried out in each case for 60 seconds with a waiting time of 0 seconds.

50 From the raw data curve, the logic program calculates on the basis of volume distribution, taking into account Mie theory and Fraunhofer's optical model, particle size distribution. Typically, a bimodal distribution curve is found with a Modality A between 0 - 1 μm (maximum at approximately 0.2 μm) and with a Modality B between 1 - 100 μm (maximum at approximately 5 μm). According to Figure 1, the WK coefficient can be determined from this, which is indicated as a value

55 average from six individual measurements.

PH value determination

The procedure supported by DIN EN ISO 787-9 is used to determine the pH value of an aqueous suspension of silicic acids at 20 ° C. For this, an aqueous suspension of the sample to be investigated is prepared. After a brief shaking of the suspension, its pH value is determined by a pH measuring device that has been previously calibrated.

Realization

Before carrying out the pH measurement, the pH measuring device (from the Knick entity, type: 766 pH-Meter Calimatic with a temperature sensor) and the pH electrode (measuring chain of a rod must be calibrated) of the Schott entity, type N7680) mediating the use of buffer solutions at 20 ° C. The calibration function must be chosen in such a way that the two buffer solutions used include the expected pH value of the sample (buffer solutions with a pH of 4.00 and 7.00, a pH of 7.00 and a pH of 9.00 and eventually a pH of 7.00 and 12.00). In the case of the use of granules, 20.0 g of a silicic acid are first shredded by a mill (from the Krups entity, model KM 75, article number 2030-70) for 20 s. 5.00 g of a pulverulent or spherical silicic acid with a moisture content of 5 ± 1% (if necessary the moisture content is adjusted by drying at 105 ° C in a drying cabinet or by uniform wetting, before eventual shredding), they are weighed on a precision scale, with an accuracy of 0.01 g, and placed in a wide-mouth jar of previously tared glass. 95.0 ml of deionized water are added to the sample. The suspension is then shaken in the closed container for a period of 5 minutes by means of a shaking machine (from the Gerhardt entity, model LS10, 55 W, step 7) at room temperature. The pH value is measured directly after shaking. For this, the electrode is rinsed first with deionized water and then with a part of the suspension, and then immersed in the suspension. After the addition of a magnetized fish (Magnetfisch) in the suspension, the pH measurement is carried out at a constant rate of agitation with a slight thrombus formation of the suspension. When the pH measuring device indicates a constant value, the pH value is read on the indicator.

In the case of the use of a hydrophobic silicic acid, the embodiment is carried out in an analogous manner, but then 5.00 g of the optionally shredded sample with a moisture content of 5 ± 1% is weighed and introduced into the scale of precision with an accuracy of 0.01 g, and introduced into a wide-mouth jar of previously tared glass. 50.0 ml of methanol p. A. and 50.0 ml of deionized water and then the suspension is shaken in the closed container for a period of 5 minutes by means of a shaking machine (from the Gerhardt entity, model LS10, 55 W, step 7) at the temperature ambient. The pH value is also measured by stirring, but after exactly 5 min.

Determination of the solid material content of the filter cake

According to this method, the solid material content of the filter cake is determined by removing the volatile portions at 105 ° C.

Realization

In a tare and dry porcelain tray (with a diameter of 20 cm), 100.00 g of the filter cake (inlet weighing E) is weighed and introduced. Eventually, the filter cake is crumbled with a spatula in order to obtain uncooked pieces of a maximum of 1 cm3. The sample is dried at 105 ± 2 ° C in a drying cabinet until proof of weight is obtained. The sample is then cooled to room temperature in a drying cabinet with silica gel as a drying agent. The output weighing A is determined gravimetrically. The content of solid materials in% is determined according to 100% - (((E in g - A in g) * 100%) / (E in g)).

Determination of electrical conductivity

The determination of the electrical conductivity (LF) of the silicic acids is carried out in an aqueous suspension.

Realization

In the case of the use of granules, in the first place, 20.0 g of a silicic acid are crushed by a mill (from the Krups entity, model KM 75, article number 2030-70). 4.00 g of a pulverulent or spherical silicic acid with a moisture content of 5 ± 1% (if necessary, the moisture content is adjusted, before eventual shredding, by drying at 105 ° C in a drying cabinet or by uniform wetting) they are suspended in 50.0 ml of deionized water and heated at 100 ° C for 1 min. The sample cooled to 20 ° C is completed to exactly 100 ml and homogenized by shaking.

The measuring cell of the conductivity measuring device LF 530 (of the WTW entity) is rinsed with a small amount of the sample, before the measuring cell LTA01 is submerged into the suspension. The value indicated in the visual presenter corresponds to the conductivity at 20 ° C, since the external temperature sensor TFK 530 performs an automatic temperature compensation. This temperature coefficient, as well as the cell constant k must be checked before each series of measurements. As a calibration solution, 0.01 mol / l of a potassium chloride solution (LF at 20 ° C = 1278 μS / cm) is used.

The following Examples should explain the invention in greater detail without limiting its extent.

Example 1

In a stainless steel based reactor with a propeller stirring system and a double envelope heating system, 41.60 l of water are pre-arranged as well as 0.02 kg of a soluble glass (density 1,348 kg / l, 27.1% of SiO2, 8.00% of Na2O) and 0.50 kg of Na2SO4. Then, with intense stirring at 60 ° C for 55 minutes, 8.90 l / h of a soluble glass and approximately 2.10 l / h of a sulfuric acid are added (density 1.40 kg / l, 50.6% of H2SO4). This metered addition of sulfuric acid is regulated in such a way that a pH value of 9.0 (measured at room temperature) reigns in the reaction medium. Then, the addition of the soluble glass is stopped and the sulfuric acid is continued to be provided, until a pH value of 3.3 (measured at room temperature) has been reached. The suspension obtained is filtered in the usual way and washed with water. The filter cake, with a solid material content of 18%, is liquefied with an aqueous sulfuric acid and with shear equipment. The silicic acid feed, with a solid material content of 16%, is then dried by atomization. The powdery product obtained has a surface area according to BET of 238 m2 / g, a surface area according to CTAB of 199 m2 / g, a DBP absorption of 288 g / (100 g), a number of Sears V2 of 23.6 ml / ( 5 g) and a conductivity of 570 μS / cm.

Example 2

In a stainless steel based reactor with a propeller stirring system and a double envelope heating system, 41.6 l of water as well as 0.02 kg of a soluble glass (density 1,348 kg / l, 27.1% of SiO2, 8.00% of Na2O) and 0.5 kg of Na2SO4. Then, with intense stirring at 64 ° C for 56 minutes, 8.95 l / h of a soluble glass and approximately 2.05 l / h of a sulfuric acid are added (density 1.40 kg / l, 50.6% of H2SO4). This metered addition of sulfuric acid is regulated in such a way that a pH value of 9.0 (measured at room temperature) reigns in the reaction medium. Then, the addition of the soluble glass is stopped and the sulfuric acid is continued to be provided, until a pH value of 3.3 (measured at room temperature) has been reached. The suspension obtained is filtered in the usual way and washed with water. The filter cake, with a solid material content of 18%, is liquefied with an aqueous sulfuric acid and with shear equipment. The silicic acid feed, with a solid material content of 16%, is then dried by atomization. The powdery product obtained has a surface area according to BET of 233 m2 / g, a surface area according to CTAB of 193 m2 / g, a DBP absorption of 276 g / (100 g), a number of Sears V2 of 23.2 ml / ( 5 g) and a conductivity of 420 μS / cm.

Example 3

Investigation of precipitated silicic acids, according to the invention, from Examples 1 and 2 in a mixture of SBR rubber in emulsion. As a state of the art, silicic acid for easily dispersible rolling surfaces, Ultrasil 7000 GR, and silicic acid with a high specific surface area, Zeosil 1205 MP, were chosen. Ultrasil 7000 GR is a well dispersible precipitated silicic acid of the entity Degussa AG, with a surface area according to CTAB of 160 ± 10 m2 / g. Zeosil 1205 MP is a silicic acid with a high specific surface area of the Rhodia entity, with a surface area according to CTAB of 200 ± 10 m2 / g.

The recipe used for the rubber mixtures is indicated in the following Table 1. In this context the phr unit means weight proportions, referred to 100 parts of the raw rubber used. Mixtures A and B contain the silicic acid according to the invention and mixtures R1 and R2 serve as references according to the state of the art. In order to assess the quality of the dispersion, the shear forces introduced when mixing should be kept as constant as possible. This can be achieved by a dosed addition of the silane, adapted to the surface according to CTAB, in order, however, to also keep the cross-linking density comparable in the case of a modified amount of silane, a sulfur correction of mode corresponding to the sulfur content of the silane (H.-D. Luginsland, J. Fröhlich, A. Wehmeier, article (paper) No. 59 presented at the ACS Congress April 24-27, 2001, Providence / Rhode Island, USA .UU).

The general procedure for the production of mixtures of rubbers and their vulcanized materials is described in the book: "Rubber Technology Handbook", W. Hofmann, Hanser 1994 editorial.

Table 1

1st stage

-R1 -R2  -TO -B-

Buna 1500

100  100  100 100

Ultrasil 7000 GR

60 --- --- ---

Zeosil 1205 MP

--- 60 --- ---

Silicon acid according to Example 1

--- --- 60 ---

Silicon acid according to Example 2

--- --- --- 60

Yes 69

4.80  5.77  5.86 5.68

Renopal NS

fifteen  fifteen  fifteen fifteen

Stearic acid

one one one one

ZnO

3 3 3 3

Vulkanox HS / LG

one one one one

2nd Stage

Discontinuous stage 1

3rd stage

Discontinuous stage 2

Vulkacit CZ / EG

1.0  1.0  1.0 1.0

Vulkacit Thiuram / C

0.75  0.75  0.75 0.75

Sulfur

0.68  0.57  0.57 0.58

In the case of Buna 1500 polymer, it is an emulsion polymerized SBR copolymer from Bayer AG, with a styrene content of 23.5% by weight. Si 69 is the bis (3-triethoxy-silyl coupling coupling reagent)

5 propyl) tetrasulfan from the entity Degussa AG. Renopal NS is a mineral oil from the Fuchs Mineralölwerke entity. Vulkanox HS / LG (TMQ), Vulkacit CZ / EG (CBS) and Vulkacit Thiuram / C (TMTD) are commercial products of Bayer AG.

Rubble mixtures are prepared in an internal mixer in a manner corresponding to the prescription of mixing given in Table 2.

Table 2

Stage 1

Settings Mixing unit Number of revolutions Print pressure Empty volume Fill level Flow temperature

Werner & Pfleiderer type E 70 min-1 5.5 bar 1.58 l 0.56 70 ºC

Mixing process from 0 to 1 min from 1 to 3 min from 3 to 4 min 4 min from 4 to 5 min 5 min Storage

Buna 1500 1/2 of the load material, If 69 1/2 of the load material, and the remaining components of the 1st stage (Renopal NS, stearic acid, ZnO, Vulkanox HS / LG) clean mix, mix out for 24 h at the temperature ambient

Stage 2

Settings Mixing unit Number of revolutions Step flow temperature Filling degree

as in Stage 1 except: 80 min-1 70 ºC 0.53

Mixing process from 0 to 2 min for 2 to 5 min 5 min Storage

interrupt Step 1 to maintain the batch temperature at 140-150 ° C by varying the number of revolutions leaving for 4 h at room temperature

Stage 3

Settings

Mixing equipment as in Stage 1 except: Number of revolutions 40 min-1 Filling degree 0.51 Pass flow temperature 40 ºC

Mixing process

from 0 to 2 min Discontinuous stage 2, Vulkacit CZ / EG, Vulkacit Thiuram / C, sulfur 2 min leave and form a raw sheet in a laboratory roller mixing device,

Homogenize: cut 3 * to the left and 3 * to the right and refute as well as turn 3 * in the case of a narrow slit between rollers (1 mm) and 3 * in the case of a wide slit between rollers (3.5 mm) and remove the raw sheet

Table 3 shows the methods for the vulcanized rubbers test.

Table 3

Physical test

Standard / Conditions

ML 1 + 4, 100 ºC, 3rd stage (-)

DIN 53523/3, ISO 667

Vulcmeter check, 165ºC

DIN 53529/3, ISO 6502

 Difference of rotation moments

 Dmax- Dmin (dNm)

 t10% and t90% (min)

Tensile test next to the ring, 23 ° C

DIN 53504, ISO 37

 Tensile strength (MPa)

 Voltage Values (MPa)

 Breaking Elongation (%)

Shore A hardness, 23 ºC (-)

DIN 53 505

Ball rebound (%)

DIN EN ISO 8307,

19 mm steel ball, 28 g

Coefficient of dispersion (%)

see text

Viscoelastic properties

DIN 53 513, ISO 2856

0 and 60 ºC, 16 Hz, preliminary force 50 N and amplitude force 25 N

Record of the measured values after a test period of 2 min, or a conditioning for 2 min E * module more complex (MPa) Loss factor so 8 (-)

The scattering coefficient is determined with a luminous optical system. The determination can be carried out by the Deutsche Institut für Kautschuktechnologie (German Institute for Rubber Technology) e.V., Hannover / Germany. In addition, the procedure is described in: H. Geisler, "Bestimmung der Mischgüte"

10 [Measurement quality determination], presented at the DIK-Workshop, November 27-28, 1997, Hannover / Germany The mixtures are vulcanized for 15 min at 165 ° C. Table 4 shows the results of the technical test for vulcanized rubbers.

15 Table 4

Raw mix data

-R1 -R2 -TO -B-

ML 1 + 4

62  84 76  72

Dmax-Dmin

5.8  5.0 5.4  4.9

t10%

4.3  3.5 3.4  3.3

t90%

4.8  8.1 8.0  7.9

Vulcanized material data

Tensile strength

23.5  23.4 23.4  21.7

100% voltage value

1.5 2.0 1.5 1.4

300% voltage value

7.0 6.6 6.2 5.4

Breaking Elongation

640 670 660 680

Shore hardness A

57  65 60  58

Dispersion coefficient

96 78 96 94

As recognized with the aid of the data presented in Table 4, the mixtures A and B with the silicic acid according to the invention have a higher Mooney viscosity than the reference mixture R1. This has to be attributed to the stronger silicic acid lattice, conditioned by the higher specific surface area of the silicic acid of the 5 silicic acids according to the invention compared to that of the reference silicic acid Ultrasil 7000 GR. Compared to silicic acid with a high conventional specific surface area Zeosil 1205 MP in the reference mixture R2, the viscosity, however, has been advantageously decreased, which implies an improved workability. The t90% vulcanization period is extended due to the lack of adaptation of the accelerating agent compared to the Ultrasil 7000 GR and has to be attributed to the increased specific surface area of the silicic acids 10 according to the invention; Likewise, the crosslink density measured as a difference of the Dmax-Dmin rotation moments has been reduced. In spite of the lack of adaptation of the accelerating agent, the tensile strengths, the tension values and the hardnesses of the mixtures A and B according to the invention indicate a good reinforcement. The hardnesses of the mixtures R1, A and B are comparable, while the hardness of the mixture R2 has manifestly increased. This already shows an insufficient dispersion of silicic acid with a high specific surface area.

15 conventional in R2. The dispersion quality of mixtures A and B, with a value above 90%, is very good and reaches the level of the highly dispersible silicic acid in R1, while the dispersion in R2 with the silicic acid with high Specific surface according to the state of the art is manifestly worse.

Example 4

Investigation of precipitated silicic acids, according to the invention, from Examples 1 and 2 in a mixture of S-SBR and BR rubbers. As the prior art, the silicic acids Ultrasil 7000 GR and Zeosil 1205 MP were chosen again.

25 The recipe used for the rubber mixtures is indicated in the following Table 5. The reference silicic acid Ultrasil 7000 GR in the mixture R3 was modified with 6.4 phr of Si 69. In order to take into account the highest Zeosil 1205 MP reference silicic acid surface and precipitated silicic acids according to the invention, in mixtures R4, C and D, the amount of silane was increased to 8 phr and the amount of sulfur was correspondingly decreased. Sulfur correction is required corresponding to the sulfur content of the silane

30 (H.-D. Luginsland, J. Fröhlich, A. Wehmeier, article (paper) No. 59 presented at the ACS Congress April 24-27, 2001, Providence / Rhode Island, USA).

Table 5

1st stage

-R3 -R4 -C- -D-

Buna VSL 5025-1

96  96  96 96

Buna CB 24

30 30 30 30

Ultrasil 7000 GR

80 --- --- ---

Zeosil 1205 MP

--- 80 --- ---

Silicon acid according to Example 1

--- --- 80 ---

Silicon acid according to Example 2

--- --- --- 80

Yes 69

6.4  8.0  8.0 8.0

ZnO

2 2 2 2

Stearic acid

2 2 2 2

Naftolen ZD

10  10  10 10

Vulkanox 4020

1.5 1.5 1.5 1.5

Protektor G35P

one one one one

2nd Stage

Discontinuous stage 1

3rd stage

Discontinuous stage 2

Vulkacit D / C

2.0  2.0  2.0 2.0

Vulkacit CZ / EG

1.5  1.5  1.5 1.5

Perkazit TBZTD

0.2  0.2  0.2 0.2

Sulfur

1.51  1.33  1.33 1.33

35 In the case of VSL 5025-1 polymer, it is a solution polymerized SBR copolymer from Bayer AG, with a styrene content of 25% by weight and a butadiene content of 75% by weight. The copolymer contains 37.5 phr of an oil and has a Mooney viscosity (ML 1 + 4/100 ° C) of 50 ± 4. In the case of Buna CB 24 polymer it is a 1,4-polybutadiene cis (of the type neodymium) from Bayer AG with a cis-1.4 content of at least 97% and a Mooney viscosity of 44 ± 5. Naftolen ZD from the aromatic oil of the

40 Chemetall entity. In the case of Vulkanox 4020, it is the 6PPD of the Bayer AG entity and the Protektor G35P is an ozone protective wax of the HB-Füller GmbH entity. The Vulkacit D / C (DPG) and Vulkacit CZ / EG (CBS)

They are commercial products of the Bayer AG entity. The Perkazit TBZTD is obtainable from the Akzo Chemie entity GmbH. Rubble mixtures are prepared in an internal mixer in a manner corresponding to the prescription of mixing given in Table 6.

Table 6

Stage 1

Settings Mixing unit Number of revolutions Print pressure Empty volume Fill level Flow temperature

Werner & Pfleiderer type E 70 min-1 5.5 bar 1.58 l 0.56 80 ° C

Mixing process from 0 to 1 min from 1 to 3 min from 3 to 4 min 4 min from 4 to 5 min Storage

Buna VSL 5025-1 + Buna CB 24 1/2 of the load material, ZnO, stearic acid, Naftolen ZD, Si 69 1/2 of the load material, Vulkanox 4020, Protektor G35P clean mix and leave for 24 h at room temperature

Stage 2

Settings Mixing unit Number of revolutions Degree of filling

as in Stage 1 except: 80 min-1 0.53

Mixing process from 0 to 2 min for 2 to 5 min 5 min Storage

interrupt Step 1 to maintain the batch temperature at 140-150 ° C by varying the number of revolutions leaving for 4 h at room temperature

Stage 3

Settings Mixing unit Number of revolutions Filling degree Step flow temperature

as in Stage 1 except: 40 min-1 0.51 50 ° C

Mixing process from 0 to 2 min 2 min Homogenize:

Discontinuous stage 2, Vulkacit D / C, Vulkacit CZ / EG, Perkazit TBZTD, sulfur come out and form a raw sheet in a laboratory roller mixing device, (Diameter 200 mm, length 450 mm, Flow temperature 50 ºC ) cut 3 * on the left and 3 * on the right and refute as well as turn 8 * in the case of a narrow slit between rollers (1 mm) and 3 * in the case of a wide slit between rollers (3.5 mm ) and remove the raw sheet

Table 3 shows the methods for the vulcanized rubbers test.

The mixtures are vulcanized for 20 min at 165 ° C. Table 7 shows the results of the technical test for vulcanized rubbers.

Table 7

Raw mix data

-R3 -R4 -C- -D-

ML 1 + 4

60  82 72  69

Dmax-Dmin

16.4  19.0 16.8  17.5

t10% t90%

1.57.4  0.7 6.7 1.28.6  1.2 8.0

Vulcanized material data

Tensile strength 100% tension value 300% tension value Break elongation

13.3 1.8 10.4 350 15.4 3.0 12.1 350 12.4 1.9 9.8 350 13.6 1.8 9.5 370

Shore hardness A

60  71 63  63

Ball bounce, 60 ºC

60.9 56.2 60.9 59.3

E * (0 ºC) E * (60 ºC) tan 8 (0 ºC) tan 8 (60 ºC)

18.0 7.7 0.458 0.122 26.4 8.8 0.527 0.145 23.2 9.1 0.440 0.129 23.0 8.8 0.443 0.125

Dispersion coefficient

98 81 91 95

As recognized with the help of the data presented in Table 7, because of the higher specific surface area of the silicic acids according to the invention, the Mooney viscosities of the mixtures C and D have increased slightly compared to that of the R3, but they are still better than those of the reference mixture R4 hardly elaborable, which represents the state of the art. With the exception of the R4 mixture, the vulcanization characteristics (Dmax-Dmin, t90%, t10%) of all mixtures are very similar. Also the tensile strengths and the tension values of R3, C and D are comparable, while the R4 has a manifestly higher hardness and tension value of 100% (or) which indicates a clearly silicic acid lattice higher because of the worst dispersion. The advantages of mixtures C and D over R3 can be recognized in the dynamic modules 10 * E ° 0 ° C and 60 ° C increased. These higher rigidities are particularly important for high-speed PKW and motorcycle tires, since they indicate improved dry handling and higher cornering stability. In spite of the silicic acids with higher surfaces according to CTAB, which are used in mixtures C and D, the values of tan 8 (60 ° C) are advantageously almost unchanged against the mixture R3, which allows predicting a comparable rolling resistance, while the R4 mixture according to the state of the art has a tan 8 (60 ° C) and therefore a significantly higher rolling resistance. The good reinforcement, in combination with the high surface area according to CTAB of the silicic acids according to the invention, makes an improved road abrasion of mixtures C and D possible. This improvement in road abrasion can be achieved in mixtures of natural rubbers also in the case of the use of silicic acids with high specific surfaces according to the invention, as they find use in mixtures

20 for rolling surfaces of LKW. In particular, in combination with a high-structure carbon black that has a high specific surface such as N 121, excellent road abrasion can be achieved in the case of LKW tires. Precisely in this sector of use, an improvement in the behavior of Cut & Chip and Chunking is also of special interest and can be carried out by using the specific high surface silicic acids according to the invention.

Example 5

In a stainless steel based reactor with a propeller stirring system and a double envelope heating system, 29.20 l of water are pre-arranged as well as approximately 0.01 kg of

30 a soluble glass (density 1,352 kg / l, 27.6% SiO2, 8.20% Na2O) such that a pH value of 10.0 (measured at room temperature) is reached.

Then, with intense stirring at 66 ° C for 66 minutes, 7.90 l / h of a soluble glass and about 1.90 l / h of a sulfuric acid are added (density 1.40 kg / l, 50.6% of H2SO4). This addition

The metered dose of sulfuric acid is regulated in such a way that a pH value of 10.0 (measured at room temperature) reigns in the reaction medium. Then, the addition of the soluble glass is stopped and the sulfuric acid is continued to be provided, until a pH value of 3.0 (measured at room temperature) has been reached.

The suspension obtained is filtered in the usual way and washed with water. The filter cake, with a content of

40 solid materials of 23.8%, it is liquefied with an aqueous sulfuric acid and with a shear equipment. The silicic acid feed, with a solid material content of 17%, is then dried by atomization.

The powdery product obtained has a surface area according to BET of 283 m2 / g, a surface area according to CTAB of 231 m2 / g, a DBP absorption of 293 g / (100 g), a number of Sears V2 of 29.7 ml / ( 5 g) and a conductivity of 320

45 μS / cm.

Example 6

Investigation of the precipitated silicic acid according to the invention from Example 5 in a mixture of rubbers 50 S-SBR and BR. As the state of the art, Ultrasil 7000 GR silicic acid was chosen.

The recipe used for the rubber mixtures is indicated in the following Table 8. The reference silicic acid Ultrasil 7000 GR in the mixture R5 was modified with 6.4 phr of Si 69. In order to take into account the highest surface area of the silicic acid according to the invention, in the mixture E the amount of silane was increased to 8 phr and the amount of sulfur was correspondingly decreased. A correction for sulfur is required corresponding to the sulfur content of the silane (H.-D. Luginsland, J. Fröhlich, A. Wehmeier, article (paper) No. 59 presented at the ACS congress April 24-27, 2001 , Providence / Rhode Island, USA).

Table 8

1st stage

-R5 -AND-

Buna VSL 5025-1

96 96

Buna CB 24

30 30

Ultrasil 7000 GR

80 ---

Silicon acid according to Example 5

--- 80

Yes 69

6.4 8.0

ZnO

2 2

Stearic acid

2 2

Naftolen ZD

10 10

Vulkanox 4020

1.5 1.5

Protektor G35P

one one

2nd Stage

Discontinuous stage 1

3rd stage

Discontinuous stage 2

Vulkacit D / C

2.0 2.0

Vulkacit CZ / EG

1.5 1.5

Perkazit TBZTD

0.2 0.2

Sulfur

1.51 1.33

In the case of VSL 5025-1 polymer, it is an SBR copolymer polymerized in solution from Bayer AG, with a styrene content of 25% by weight and a butadiene content of 75% by weight. The copolymer 10 contains 37.5 phr of an oil and has a Mooney viscosity (ML 1 + 4/100 ° C) of 50 ± 4. In the case of Buna CB 24 polymer it is a 1,4-polybutadiene cis (del type of neodymium) of the Bayer AG entity with a cis-1.4 content of at least 97% and a Mooney viscosity of 44 ± 5. Naftolen ZD from the Chemetall entity is used as aromatic oil. In the case of Vulkanox 4020, it is the 6PPD of the Bayer AG entity and the Protektor G35P is an ozone protective wax of the HB-Füller GmbH entity. The Vulkacit D / C (DPG) and Vulkacit CZ / EG (CBS)

15 are commercial products of the Bayer AG entity. The Perkazit TBZTD is obtainable from the Akzo Chemie GmbH. Rubble mixtures are prepared in an internal mixer in a manner corresponding to the mixing prescription given in Table 9.

20 Table 9

Stage 1

Settings Mixing unit Number of revolutions Print pressure Empty volume Fill level Flow temperature

Werner & Pfleiderer type E 70 min-1 5.5 bar 1.58 l 0.56 80 ° C

Mixing process from 0 to 1 min from 1 to 3 min from 3 to 4 min 4 min from 4 to 5 min Storage

Buna VSL 5025-1 + Buna CB 24 1/2 of the load material, ZnO, stearic acid, Naftolen ZD, Si 69 1/2 of the load material, Vulkanox 4020, Protektor G35P clean mix and leave for 24 h at room temperature

Stage 2

Settings Mixing unit Number of revolutions Degree of filling

as in Stage 1 except: 80 min-1 0.53

Mixing process from 0 to 2 min for 2 to 5 min

interrupt Step 1 to maintain the batch temperature at 140-150 ° C by varying the number of revolutions

5 min Storage

leave for 4 h at room temperature

Stage 3

Settings Mixing unit Number of revolutions Filling degree Step flow temperature

as in Stage 1 except: 40 min-1 0.51 50 ° C

Mixing process from 0 to 2 min 2 min Homogenize:

Discontinuous stage 2, Vulkacit D / C, Vulkacit CZ / EG, Perkazit TBZTD, sulfur come out and form a raw sheet in a laboratory roller mixing device, (Diameter 200 mm, length 450 mm, Flow temperature 50 ºC ) cut 3 * on the left and 3 * on the right and refute as well as turn 8 * in the case of a narrow slit between rollers (1 mm) and 3 * in the case of a wide slit between rollers (3.5 mm ) and remove the raw sheet

Table 3 shows the methods for the vulcanized rubbers test.

The mixtures are vulcanized for 20 min at 165 ° C. Table 10 shows the results of the technical test for vulcanized rubbers.

Table 10

Raw mix data

-R5 -AND-

ML 1 + 4

66 104

Dmax-Dmint10% t90%

 16.8 1.7 6.5 23.5 0.8 15.3

Vulcanized material data

Tensile strength 100% tension value 300% tension value

13.0 2.0 10.1 11.8 2.3 9.9

Breaking Elongation

350 335

Shore hardness A

66 72

Ball bounce, 60 ºC

63.8 59.7

E * (0 ºC) E * (60 ºC) tan 8 (0 ºC) tan 8 (60 ºC)

19.8 8.0 0.463 0.110 48.1 14.9 0.408 0.115

Dispersion coefficient

98 91

Abrasion DIN, 10 N, mm3

86  73

As recognized with the help of the data presented in Table 10, the mixture E shows against the

10 mixtures R5 (U 7000 GR), C and D, dynamic modules E * 0 ºC and 60 ºC advantageously increased. These higher rigidities are particularly important for high-speed PKW and motorcycle tires, since they indicate improved dry handling and higher cornering stability. In spite of the silicic acid with a higher surface area according to CTAB, which is used in the mixture E, the values of tan 8 (60 ° C) are advantageously almost unchanged against the mixture R5, which allows predicting a comparable resistance to the

15 rolling.

Additionally, the mixture E shows an improved DIN abrasion, which together with the good reinforcement in combination with the high surface area according to CTAB of the silicic acid according to the invention makes an improved road abrasion possible. This improvement in road abrasion can be achieved in mixtures of natural rubbers also in the case of the use of silicic acids with high specific surfaces according to the invention, as they find use in mixtures for rolling surfaces of LKW. In particular, in combination with a high structure carbon black having a high specific surface, such as N 121, excellent road abrasion can be achieved in the case of LKW tires. Precisely in this sector of use, an improvement in the behavior of Cut & Chip and Chunking is also of special interest and

25 can be carried out by use of the specific high surface silicic acids according to the invention.

Claims (16)

1. Silicon precipitation acid, characterized by an area according to BET 200 - 300 m2 / g a surface according to CTAB; 170 m2 / g a DBP index 200 - 300 g / (100 g) a number of Sears V2 26-35 ml / (5 g) 2. Silicon precipitation acid according to claim 1, characterized because The surface area according to CTAB is a maximum of 300 m2 / g.

3.

 Silicon precipitation acid according to one of claims 1 or 2, characterized in that the precipitation silicic acid has a WK coefficient of: 3.4 (ratio of the peak height of the particles not decomposable by ultrasound in the size range of 1.0 - 100 μm at the peak height of the decomposed particles in the region of sizes <1.0 μm).

Four.

 Silicon precipitation acids according to one of claims 1 to 3, characterized because

Its surfaces have been modified with organosilanes of formulas I through III [SiR1n (RO) r (Alk) m (Ar) p] q [B] (I), SiR1n (RO) 3-n (Alkyl) (II) , or SiR1n (RO) 3-n (Alkenyl) (III), in which they mean B: -SCN, -SH, -Cl, -NH2, -OC (O) CHCH2, -OC (O) C (CH3) CH2 (when q = 1) or -Sw- (when q = 2), where B chemically bonded to Alk, R and R1: an aliphatic, olefinic, aromatic or aryl aromatic radical with 2-30 C atoms, which It may optionally be substituted with the following groups: a hydroxy, amino, alcoholate, cyanide, thiocyanide, halogen, sulfonic acid, sulfonic acid ester, thiol, benzoic acid ester, benzoic acid ester radical , of carboxylic acid, of carboxylic acid ester, of acrylate, of methacrylate, of organosilane, with R or R1 having an equal or different meaning or substitution. n: 0, 1 or 2, Alk: a divalent, unbranched or branched hydrocarbyl radical with 1 to 6 carbon atoms, m: 0 or 1, Ar: an aryl radical with 6 to 12 C atoms, preferably with 6 C atoms, which may be substituted with the following groups: a hydroxy, amino, alcoholate, cyanide, radical of 35 thiocyanide, halogen, sulfonic acid, sulfonic acid ester, thiol, benzoic acid, benzoic acid ester, carboxylic acid, carboxylic acid ester, acrylate, methacrylate, organosilane, p: 0 or 1, with the proviso that p and n do not mean 0 at the same time, q: 1 or 2, w: a number from 2 to 8, r: 1, 2 or 3, with the proviso that r + n + m + p must be = 4, Alkyl: a univalent, unbranched or branched saturated hydrocarbyl radical, with 1 to 20 carbon atoms, preferably with 2 to 8 carbon atoms, Alkenyl: a univalent, unbranched or branched unsaturated hydrocarbyl radical having 2 to 20 carbon atoms, preferably with 2 to 8 carbon atoms. 5. Procedure for the production of a precipitation silicic acid with an area according to BET 200 - 300 m2 / g a surface according to CTAB; 170 m2 / g a DBP index 200 - 300 g / (100 g) a number of Sears V2 23 - 35 ml / (5 g) realizing that a) an aqueous solution of an organic and / or inorganic salt and an alkali metal or alkaline earth metal silicate and / or an organic and / or inorganic base with a pH of 9 is previously available, b) to this preload are added dosed with stirring at 55-95 ° C for 10-120 minutes at the same time a soluble glass and an acidification agent, e) is acidified with sulfuric acid at a pH value of approximately 3.5 and f) is filtered and dried. 6. Method according to claim 5, characterized because The concentration of organic and / or inorganic salt in the previous load is 0.01 to 5 mol / l. Method according to claim 5 or 6, characterized in that between stages b) and c) steps c) of stopping the dosed addition are carried out for 30-90 minutes while maintaining temperature of the temperature and d) of addition Simultaneously dosed a soluble glass and an acidifying agent, thereto temperature with stirring for 20-120 minutes. 8. Method according to claim 7, characterized because the acidifying agent and / or the soluble glass have in stages b) and d) in each case the same concentration or flow rate Method according to claim 7, characterized in that the acidification agent and / or the soluble glass have in stages b) and d) in each case another concentration or different flow rate.

10.

 Method according to claim 9, characterized because in the case of the same concentration of the acidification agent and / or the soluble glass in steps b) and d) the Inflow rate of these in stage d) is 125-140% of the flow rate in stage b).

eleven.

Method according to one of claims 5 to 10,

25 characterized in that for drying a circulating current drying apparatus, an atomizing drying apparatus, a floor drying apparatus, a conveyor belt drying apparatus, a rotary tube drying apparatus, a sudden evaporation drying apparatus, an apparatus are used for drying. Rotary dryer and sudden evaporation or a nozzle tower.

12.

 Procedure according to claims 5 to 11, characterized because after drying a granulation with a roller compactor is carried out.

13.

 Method according to one of claims 5 to 12,

characterized in that during the steps b) and / or d) an addition of an organic or inorganic salt is made. 14. Method according to one of claims 5 to 13, characterized in that the granulated or non-granular precipitation silicic acids are modified with organosilanes in mixtures of 0.5 to 50 parts, based on 100 parts of the precipitation silicic acid, in particular from 1 to 15 parts, referred to 100 parts of the precipitation silicic acid, the reaction being carried out between the precipitation silicic acid and the organosilane during the preparation of the mixture (in situ) or outside it by application by atomization and subsequent tempering of the mixture, or mixing of the organosilane and the suspension of silicic acid with subsequent drying and tempering. 15. Mixtures of elastomers, mixtures of vulcanizable rubbers and / or vulcanized materials, containing precipitation silicic acids according to one of claims 1 to 4.

16.

 Covers (of tires) containing a precipitation silicic acid according to claims 1 to 4.

17.

 Covers for useful motor vehicles, which contain a precipitation silicic acid according to one of claims 1 to 4.

18.

 Motorcycle covers, which contain a precipitation silicic acid according to one of claims 1 to 4.

19.

 Covers for high-speed motor vehicles, which contain a silicic acid according to one of claims 1 to 4.

 WK coefficient determination    Fig. 1 Peak height of non-decomposable particles (B) WK = -------------------------------- Peak height of decomposed particles (A)   A ’= range from 0 to <1.0 μm   B ’= range of 1.0 μm - 100 μm.