MXPA99011659A - Rubber compositions containing organosilyl polysulfanes - Google Patents

Abstract

A rubber mixture contains at least one organosilanepolysulfane and at least one phosphorus compound as desulfuring reagent. Independent claims are included for:(1) preparation of a rubber mixture by mixing a rubber, at least one filler, an organosilanepolysulfane (OSPS), and a desulfuring reagent;(2) a molded body obtained from the rubber mixture.

Description

RUBBER MIXTURES CONTAINING ORGANGANIC POLYPOLISULPHANES DESCRIPTION OF THE INVENTION The present invention relates to rubber mixtures containing organosilanepolysulfanes. It is known to use organosilane polysulfones as tackifiers or reinforcing additives in rubber mixtures filled with rust, such as for example contact surfaces and other parts of automotive wheels (DE 2 141 159, DE 2 212 239, US 3 978 103, US 4 048 206). This type of organosilanepolyols, such as, for example, bis- (3- [triethoxysilyl] -propyl) tetrasulfan (TESPT), generally consists of a mixture of polysulfane, in which the lengths of the sulfan chains (SJ in general are within the range of 21 to 10. It is also known that in the use of this type of adherent agents of rubber mixtures filled with oxides, the process temperatures must be maintained above 130 ° C, to allow the reaction between the silicic acid and the organosilane. The plasticity of the mixture is reduced with a higher mixing temperature, accelerating the reaction of the organosilanes with silicic acid and the expulsion of the liberated alcohol, and it is known that the organosilanpolis sulphane preponderantly used, such as bis- (3-) [triethoxysilyl] -propyl) etrasulfan, require special care during your REF .: 32186 elaboration in the rubber, to avoid a prevulcanización in the mixture of the components. Especially the relatively longer chain polysulfanes with Sx > 4 at temperatures above 140 ° C tends to unwanted crosslinking reactions in the rubber. This causes, among other things, that an increase in the plasticity of the mixture becomes apparent (Górl, Münzenberg, ACS-Meeting Rubber Division, Anaheim, California / US, May 1997, 8). It is also known to use organosilanes with chains of shorter polysulfane (WO-A 97/48264, DA 197 02 046). The known organosilanes with shorter polysulphone chains can be obtained by means of the reaction (desulphurisation by means of nucleophiles) of longer chain organosilanepolysulfanes with trivalent phosphorus compounds, sulfites or cyanides (D 195 41 404 and EP-A-845 472). However, the preparation of these organosiyanopolysulfins requires at least one additional process step. It is complicated and expensive. The object of the invention are rubber mixtures containing at least one organosilane and at least one reagent for the desulphurisation of the classes of compounds formed by trivalent phosphorus compounds. According to the invention it was found that in the preparation of the mixture the tendency to scorch can be largely avoided with the use of long-chain organosilpolysulfanes in rubber mixture, by direct addition of trivalent phosphorus compounds, sulfites or cyanides. , which are capable of reducing the fraction of the long chain polysulfanes by means of a desulfurization reaction. As organosilane polysulfones, known organosiyanopolysulfins can be used. In particular, organosilane-polysulfones corresponding to the formula I (R ^ R3 SiR) 2Sx I may be used, wherein R1, R2, R3, which may be identical or independent of each other, are: H, alkyl having 1 to 4 carbon atoms, alkoxy with 2 to 4 carbon atoms or halogen, wherein halogen can be Cl, Br; it being preferred that R: = R2 = R3 = methoxy or ethoxy. R 4 can be alkylidene with from 1 to 6 carbon atoms straight or branched; X = 2 to 10 For the desulphurization of organosilane polysulfones in the mixture, the following nucleophiles are particularly suitable: Phosphines of the general structure: P (R1) 3 and P (NR2R3) 3 with R1, R2, R3 = H, alkyl, aryl, especially R1 = phenyl, and dithiophosphites of the general structure: with Rs, R6 = alkyl, aryl selected independently, The rubber mixtures exhibiting the use according to the invention of a combination of an organosilanpolis sulphan and a nucleophile for desulphurisation, and the resulting molded body after a desulphurisation step, especially rims or rim contact surfaces, possess in addition to a high safety to thermal deformation surprisingly also a high voltage value of 300% / 100%, which shows a higher coupling effectiveness of the adherent agent. This is also reflected in a bao value so d (60 ° C), which is correlated with a low rolling resistance. According to one embodiment of the invention, the rubber mixtures can contain an organosilane phannabisulphane in amounts of 0.1 to 15% by weight, especially 5 to 10% by weight, based on the amount of the filler used and at least 5 to 10% by weight. a reagent for desulfurization which makes it possible to reduce the fraction of long-chain polysulfanes by means of a desulfurization reaction, in amounts of 5 to 80% by weight, especially 10 to 40% by weight, in relation to the amount of organosilanpolis sulphan used.

In a preferred embodiment of the invention, the mixtures may contain a synthetic rubber and a silicic acid as a filler. The rubber mixtures according to the invention can be prepared by mixing together the rubber with at least one filler, an organosilane phannane and a desulfurization reagent. The addition of the organosianes, the nucleophile for desulfurization, as well as the addition of the filler is preferably carried out in a thermomechanical mixing step at temperatures of 80 to 200 ° C, especially 140 to 180 ° C. The addition of the nucleophiles can be enhanced preferably at the beginning of the preparation of the mixture, to ensure the high heat stability of the mixture according to the invention, already at an early stage of the preparation of the mixture. Fillers can be used for the rubber mixtures according to the invention: carbon blacks that were prepared according to the flame, furnace or gas carbon black method, having a BET surface area of 20 to 200 m / g . Highly dispersible silicic acids, prepared for example by the precipitation of silicates solutions or by flame hydrolysis of silicon halides with specific surfaces of 5 to 1000, preferably 20 to 400 m2 / g (BET surface) and with primary particle sizes from 10 to 400 nm. The silicic acids can optionally be used as oxide mixed with other metal oxides such as Al, Mg, Ca, Ba, Zn and titanium oxide. Synthetic silicate, such as aluminum silicate, alkaline earth silicates such as magnesium silicate or calcium silicate with BET surfaces of 20 to 400 m2 / g and primary particle diameters of 10 to 400 nm. - Aluminum oxides with a fraction of functionalities - OH. Natural silicates such as kaolin and other silicic acids of natural origin. Fiberglass and glass fiber products (flat surfaces, strips) or glass microspheres. Preferably, carbon blacks with BET surfaces of 20 to 400 m / g or highly disperse silicas, prepared by precipitation of silicate solutions, with BET surfaces of 20 to 400 m2 in quantities of 5 to 150 parts by weight, can be used in each time to 100 rubber parts. The fillers mentioned can be used alone or in mixtures. In a particularly preferred embodiment of the process for the preparation of the mixtures, 10 to 150 parts by weight of clear filler may be used, optionally together with ° to 10? parts by weight of carbon black, as well as 0.1 to 15% parts by weight, preferably 5 to 10 parts by weight of an organosilanpolis sulphan, each time related to 100 parts by weight of the filler used, and at least one nucleophile that is capable of reducing the fraction of long-chain polysulfanes, in amounts of 5 to 80% by weight, especially of 10 to 40% by weight, based on the amount of the organosilanpolis sulphan. The organosilane can be used pure or in combination with a carrier, preferably carbon black. The addition of the nucleophile to the mixture can be carried out directly in the substance or as a mixture with another constituent part of the mixture, preferably the silane or the auxiliary agent of the rubber. The nucleophiles, the organosilane and / or the rubber auxiliaries can be used pure or in mixtures / combinations with a carrier, preferably carbon black. For the preparation of rubber mixtures according to the invention, in addition to natural rubber, synthetic rubbers are also suitable. Preferred synthetic rubbers are, for example, those described by W. Hofmann, Rubber Technology, Genter Veriag, Stuttgart 1980. These include among others: polybutadiene (BR) polyisoprene (IR) copolymerized styrene / butadiene with styrene content of 1 to 60, preferably 5 to 50% by weight (SBR) - copolymers of isobutylene / isoprene (IIR) copolymers of butadiene / acrylonitrile with an acrylonitrile content of 5 to 60, preferably 10 to 50% by weight (NBR) partially or completely hydrated BBR rubber (HNBR) - ethylene / propylene / diene copolymer (EPDM). as well as mixtures of those rubbers. For the manufacture of vehicle tires, polymerized anionic L-SBR rubbers with a crystallization temperature above -50 ° C can be used, as well as their mixtures with diene rubbers. The rubber vulcanizates according to the invention can contain other additives for rubber, such as reaction accelerators, aging protectors, thermal stabilizers, light protectors, ozone protectors, processing aids, plasticizers, adherents, propellants, colorants. , waxes, extenders, organic acids, retarders, metal oxides as well as activators, such as triethanolamine, polyethylene glycol, hexanotriol. The rubber additives can be used in customary quantities, which are adjusted according to the purpose of use. The usual amounts can, for example, be amounts from 0.1 to 50% by weight in relation to rubber. The organosilane polysulphones can serve alone as crosslinkers. The addition of other crosslinkers is usually recommended. As other known crosslinkers, sulfur or peroxide can be used. The rubber blends according to the invention may contain vulcanization accelerators. Examples of suitable vulcanization accelerators are mercaptobenzothiazoles, sulfenamides, guanidines, thiurams, dithiocarbamates, thioureas or thiocarbonates. The vulcanization accelerators and the sulfur or peroxide are used in amounts of 0.1 to 10% by weight, preferably 0.1 to 5% by weight in relation to the rubber. The vulcanization of the rubber mixtures according to the invention can be carried out at temperatures of 80 to 200 ° C, preferably 130 to 180 ° C, optionally under a pressure of 10 to 200 bar. The mixture of the rubbers with the filler, optionally the additives, the organosilane and possibly the nucleophiles can be carried out with the usual mixing aggregates such as rollers, internal mixers and mixing extruders. The vulcanizates of rubber according to the invention are suitable for the production of molded bodies, for example the manufacture of tires, contact surfaces for rims, coatings for cables, hoses, transmission belts, conveyor belts, cylinder linings, tires, shoe soles, sealing rings and damping elements. EXAMPLES With the help of examples 2 and 3, the advantages compared to the state of the art (comparative example 1), of the use according to the invention, of a combination of organosine polysulfide and a nucleophile, for desulfurization are clarified. General indications of realization The recipe used for rubber mixtures is given in table 1. In them it means the unit phr parts by weight in relation to 100 parts of raw rubber used.

Table 1 Substance Amount [phr] the. Stage Buna VSL 5025-1 96.0 Buna CB 24 30.0 Ultrasil VN3 80.0 Z ZnnOO 3 3.00 A Acciiddoo eesstteeáárriiccoo 2 2..00 Naphtholene ZD 10.0 Vulcanox 4020 1.5 - ** Protector G35P 1.0 TESPT 6.4 Triphenylphosphine 0 to 4 2a. Stage Stage 1 lot 3a. Stage Lot stage 2 Vulkacit D 2.0 Vulkacit CZ 1.5 Sulfur 1 .. The polymer VSL 50325-1 is a SBR copolymer polymerized in solution from Bayer AG with a styrene content of 25% by weight and a butadiene content of 75% by weight. weight. Butadiene binds 73% of 1.2, 10% cis 1.4 and 17% trans 1,4. The copolymer contains 37.5 phr of oil and has a Mooney viscosity (ML i + 4/100 ° C) of 50 ± 4. The polymer Buna CB 24 is cis 1,4 polybutadiene (type neodym) of Bayer AG with a cis 1,4 content of 97%, a trans 1,4 content of 2%, a content of 1,2 of 1% and a Mooney viscosity of 44 + 5. The silicic acid VN3 of Degussa AG has a BET surface area of 175 m2 / g. Bis- (3- [triethoxysilyl] -propyl) tetrasulfan (TESPT = is marketed under the trade name Si 69 of Degussa AG and has an average sulphate chain length of 4 as well as a polysulphone fraction S (x> 4) > 25% The triphenylphosphine according to examples 2 and 3 was obtained from Merck. As an aromatic oil, Naftolen ZD is used Chemetall. Vulcanox 4020 is a PPD from Bayer AG. Protektor G35P is an ozone protection wax from HB-Fuller GmbH. Vulkacit D (DPG) and Vulkacit CZ (CBS) are commercial products of Bayer AG. The rubber mixture is prepared in three stages in an internal mixer, corresponding to Table 2.

Table 2 Stage 1 Adjusted values Mixing aggregate Werner% Pfleiderer type E Friction 1: 1.11 Rev. no. 70 min "1 Die pressure 5.5 bar Empty volume 1.6 1 Degree of filling 0.55 Circulation temp 80 ° C Mixing stage 0 to 1 min Buna VSL 5025-1 + Buna CB 24 1 to 3 min 1/2 Ultrasil VN3, ZnO, Stearic acid, Naphtholen ZD, Silane, optionally Nucleophile 3 to 4 min 1/2 Ultrasil VN3, Vulcanox 4020, Protector G35P 4 min to clean 4 to 5 min to mix 5 min to clean 5 a 6 min mix and stop Temperature charge 140-150 ° C Storage 24 hours at temp. ambient Stage 2 Adjusted values Aggregate to mix as in stage 1 until: No. of re. 80 min "1 Degree of filling 0.53 Circulation temp 80 ° C Mixing stage Or at 2 min interrupt stage 1 of the load 2 to 6 min. Maintain temperature of the load at 150 ° C by varying the no. of rev 6 min stop Temp. load 150-155 ° C Storage 4 hours at temp. ambient Stage 3 Adjusted values Aggregate to mix as in stage 1 up to: Rev. no. 40 min "x Degree of filling 0.51 Circulation temperature 50 ° C Mixing stage 0 to 2 min load stage 2 + Vulkacit CZ + Vulkacit D + sulfur 2 min start and form a fleece on the laboratory rollers (diameter 200mm, length 450 mm, circulation temp 50 ° C) Homogenize: 3 * left, 3 * right cut and detach as well as cut 8 * with a narrow distance of the rollers (l mm) and 3 * with a greater distance (3.5 mm) and finally remove a fleece Temp. Load 85-95 ° C The general procedure for the preparation of rubber mixtures and their vulcanizates is described in the following book: "Rubber Technology Handbook", W. Hofmann, Hanser Verlag 1994. The vulcanization time for the test body is 60 minutes at 165 ° C. The rubber technical test is carried out in accordance with the test methods given in Table 3.

Table 3 Physical tests Standard / conditions ML 1 + 4, 100 ° C DIN 53523/3, ISO 667 Test with vulcameter, 163 ° C DIN 53529/3, ISO 6502 Hoop tensile test, 23 ° C DIN 53504, ISO 37 Tensile strength Stress values Stretch of rupture Shore A hardness, 23 ° C DIN 53 505 Viscoelastic properties, 0 and DIN 53 513, ISO 2856 60 ° C, 16 Hz, 50N previous force and 25N amplitude force Modulo complex E * Loss factor so d DIN wear, ION force DIN 53 516 Dispersion ISO / DIS 11345 Examples 1, 2 and 3: triphenylphosphine as nucleophile The embodiment of examples 1 (comparative example), 2 and 3 is carried out in accordance with the general procedure indications, in the comparative example l no triphenylphosphine is added to the mixture.

Contrary to Comparative Example 1, 2 phr is added to the mixture of Example 2, and of Example 3 additionally 4 phr triphenylphosphine, in the first mixing stage. In the illustration i the moments of turn for the examples 1, 2 and 3 at 165 ° C in the 2a are represented. mixing step in relation to time, where the addition of the moment of rotation corresponds to the tendency to prevulcanization with the given temperature. With the aid of FIG. 1, it is recognized that the increase of the torque in the examples according to the invention 2 and 3 is clearly lower than in the comparative example 1 according to the state of the art. The technical data on the rubber for the raw mix and the vulcanized are given in table 4.

Table 4: Result of raw mixture Characteristic: Unity ML (l + 4) at 100 ° C (3rd stage) ME 71 71 69 Vulcameter test 165 ° C Dmax-Dmin DNm 18.7 16.21 16.29 tl0% min 1.41 1.49 1.41 t 90%, min 27.1 24.8 19.9 Vulcanized results Characteristic: Unit 1 Tensile test: Tensile strength MPa 16.1 15.5 16.6 Tension value 100% MPa 2.4 1.9 2.1 Voltage value 300% MPa 10.9 9.3 10.4 Voltage value 300% / lOOS 4.5 4.9 5.0 Rupture stretch 380 400 400 Breakdown energy 84.6 80.1 85.9 Hardness Shore-A SH 67 61 60 Wear DIN mpr 74 67 58 Viscoelastic properties Complex module E * (0 ° C) MPa 31.2 19.5 16.3 Complex module E * (60 ° C) MPa 11.8 8.8 7.8 Loss factor tand (0 ° C) - 0.348 0.415 0.406 Loss factor tand - 0.108 0.102 0.098 (60 ° C) Dispersion With the help of table 4 it is clear that for examples 2 and 3 a table of values on the rubber technique especially good is achieved. In particular, they are positive, the voltage value 300% / 100%, which shows a high effectiveness of bonding of the silane, and the reduced value tan d (60 ° C), which correlates with a low resistance to rolling.

Claims (9)

1. REIVINDICACT NK.q i. - Rubber mixtures characterized in that they contain at least one organosilanpolis sulphan and at least one reagent for desulfurization of the class of compounds consisting of trivalent phosphorus compounds.
2. 2. - Rubber mixtures according to claim 1, characterized in that they contain organosilanpolis sulphan in an amount of 0.1 to 15% by weight, preferably 5 to 10% by weight in relation to the amount of filler used, and the reagent for desulphurization in an amount of 5 to 80% in that, preferably 10 to 40% by weight in relation to the amount of organosilanpolis sulphan used.
3. 3. Rubber mixtures according to claim 1 or 2, characterized in that they contain a synthetic rubber and a silicic acid as a filler.
4. 4. Process for the preparation of rubber mixtures according to claims 1 to 3, characterized in that a rubber, at least one organosilanpolis sulphan and a reagent for desulfurization are mixed together.
5. 5. Process for the preparation of rubber mixtures according to claim 4, characterized in that the organosilanpolis sulphan and the reagent for the desulfurization are added during a thermomechanical mixing step in a temperature range of 80 to 200 ° C.
6. 6. Molded body characterized in that it contains one of the rubber mixtures according to claims 1 to 3.
7. 7. Molded body according to claim 6, characterized in that they are tires.
8. 8. Body molded according to claim 6, characterized in that they are tire contact surfaces.
9. 9. Use of rubber mixtures according to claims 1 to 3 for the manufacture of molded bodies, especially tires and tire contact surfaces.