-1A -
The invention relates to new sulfur-functional polyorganosiloxanes, a process for their preparation and their use in rubber mixtures and for the production of mouldings.
The use of sulfur-containing organosilicon compounds such as 3-mercaptopropyltriethoxysilane or bis (3-[triethoxysilyl]propyl)tetrasulfane as silane coupling agents or reinforcing additives in rubber mixtures containing oxide filler for use as treads and other parts of automobile tyres is known (DE 2 141 159, DE 2 212 239, US 3 978 103, US 4 048 206).
Furthermore, it is known that sulfur-containing silane coupling agents can be used in the production of sealing compounds, moulds for metal casting, paint coatings and protective coatings, adhesives, asphalt mixtures and for plastics containing oxide filler.
These coupling or bonding agents form bonds both with the filler and with the elastomer and consequently bring about a good interaction between the filler surface and the elastomer: They lower the mixing viscosity and facilitate the dispersion of the filler.
EP 0 784 072 Al describes the use of a combinat-ron of a silane coupling agent and a functionalised
polyorganosiloxane having at least one functional siloxyl group which can bond to the silica.
As a coupling agent in rubber mixtures, 3-mercaptopropyltriethoxysilane is able to produce an improved silica/elastomer coupling at a comparatively low
dosage (US-A 3 350 345, FR-A-2 094 859). However, owing to the high reactivity of the SH group and consequently the well-known tendency to preliminary cross-linking as well

2
as the increased mixing viscosity, the workability of the mixtures and their industrial application are limited. It is also known that the addition of a protective additive consisting of a functional polyorganosiloxane having at least one functional siloxyl group decreases the reactivity, lowers the mixing viscosity and thus ensures that such rubber mixtures are workable (EP 0 784 072 Al).
From the economic aspect it is to be regarded as disadvantageous that, in addition to the silane coupling agents described in EP 0 784 072 Al, a siloxyl-functionalised polyorganosiloxane also has to be added to the rubber mixture.
Furthermore, it is known that the use of commercially available silane coupling agents (DE 22 55 577) having three alkoxy substituents on the silicon atom leads to the release of considerable quantities of alcohol during the mixing process.
The invention provides sulfur-functional polyorganosiloxanes corresponding to the general formula I

wherein R1, R2, R3, R4, independently of one another, denote H, (C1 - C4)alkyl, (C1 - C4)alkoxy, (C1 - C4)haloalkoxy, (C1 - C4)haloalkyl, phenyl, aryl or aralkyl and
W denotes a group which can bond to the silica and preferably can be (C1 - C4)alkoxy
or
(C1 - C4) haloalkoxy and


3
Y denotes alkyl, haloalkyl, phenyl, aryl or aralkyl and
Z denotes an alkylidene group having 0-6 carbon atoms and
A denotes a group which can bond with at least one elastomer of the rubber mixture: for q = 1 preferably a mercapto group (SH) and thiocyanate group (SCN) and for q = 2 a disulfide (S2) and a polysulfide (Sx) with x = 2 -10 and H denotes hydrogen and the sum ofk+m+n+p>3 and also k and n can
equal 0.
Preferred polyorganosiloxanes in connection with the invention which may be mentioned first of all are the following, built up from linear statistical, sequential or block polymers, in which R1, R2, R3 and R4 = alkyl, in particular methyl, W = alkoxy, in particular ethoxy, y = alkyl, in particular n-propyl, Z = alkylidene, in particular CH2CH2CH2, m and p = 1 - 100, and k and n =0-50, with the sum ofk+m+n+p=10- 150, in particular 20 - 100.
In a preferred embodiment, R1, R2, R3, R4 can be methyl, W = ethoxy, Y = n-propyl, Z = CH2CH2CH2, A = mercapto (SH) , thiocyanate (SCN) for q = 1 and A = polysulfide (Sx) and disulfide (S2) for q = 2 and k+m+n+p=10- 150, in particular 20 - 100.
The polyorganosiloxanes according to the invention wherein A = Sx can be cyclic, branched or linear in form.
The compounds according to the invention can exist both as an individual compound having a defined molecular weight, and as a mixture of oligomers having a molecular weight distribution.

4
The compounds according to the invention corresponding to the general formula I can be easily prepared in two steps, by reacting compounds corresponding to the general formula II

wherein R1, R2, R3 and R4 have the meanings given above and v can be a number between 2 and 150, with compounds corresponding to the general formula III

wherein R5 H, alkyl and X are fluorine, chlorine,

bromine and iodine, preferably chlorine, and w is a number between 0 and 15, preferably w = 1 and R5 = H (allyl chloride) and also R5 = methyl (methallyl chloride), under catalytic conditions by a mechanism of hydrosilylation using a catalyst from the family of the platinum metals, optionally in a solvent, and optionally at reaction temperatures between 20°C and 200 °C, at pressures between normal pressure or an excess pressure up to 6 bar, to form compounds corresponding to the general formula IV

wherein R1, R2, R3, R4, X, Y, Z, m, n and p have the meanings given above.


5
In the second step, compounds corresponding to the general formula IV can be reacted with MSH, MSCN or M2SX, wherein M is a metal ion and x, on statistical average,
can be a number between 2 and 10, or with M2S and S, wherein M is a metal ion, in an alcohol W-H, wherein W has the meaning given above, optionally at reaction temperatures between 20° C and 150° C and optionally under catalytic conditions, at normal pressure, to form the compounds according to the invention corresponding to the general formula I.
The compound corresponding to formula IV can advantageously be prepared as follows:- A subequivalent quantity of a mixture consisting of a compound corresponding to formula III, wherein X, R5 and w have the meanings given above, and a platinum catalyst, preferably of the Karstedt type, are added without solvents, at normal pressure or excess pressure up to 6 bar, preferably at normal pressure, at temperatures between 20° C and 2,00°C, particularly preferably 100° C to 150° C, to a compound corresponding to formula II. The mixture is stirred for 1 h to 8 d,_.preferably l to 24 h, at normal pressure or excess pressure up to 6 bar, preferably at normal pressure, at temperatures between 20°C and 200° C, particularly preferably 100° C to 120° C, then the reaction is concluded and the new compounds of type IV remain behind, mostly in the form of viscous liquids.
The reactions can advantageously be carried out under absolute conditions, that is, with the exclusion of moisture.
Various hydrosilylation processes of the type described above are known from US-A-3 159 601, EP-A-57 459, US-A-3 419 593, US-A-3 715 334, US-A-3 775 452 (Karstedt).

6
Owing to the differing selectivities of the catalysts, there can be a resulting formation of the fragment corresponding to formula V

wherein R4, X, Y and n have the meanings given above.
At a selectivity of 100%, n = 0 in compound IV and in fragment V respectively.
In a second step, the compound according to the invention corresponding to formula I can advantageously be prepared as follows:- A compound corresponding to formula IV, wherein R1, R2, R3, R4, w, X, Y, Z, m, n and p have the meanings given above is added to a suspension of MSH, MSCN or M2S and S, or to previously prepared M2SX, in an alcohol W-H. Hydrogen gas is formed in this process. The reaction is heated for 1 h to 8 d, preferably 1 to 24 h, at normal pressure, to temperatures between 20 ° C and 150 OC, particularly preferably at the boiling point of the alcohol W-H and, on conclusion of the reaction, the precipitate formed is filtered off. After the removal of the excess alcohol W-H, the new compounds of type I generally remain behind in the form of viscous liquids or low-melting solids.
The alcoholysis and sulfur-functionalisation take place' Simultaneously in the process according to the invention. No additional catalyst is required for the alcoholysis. In the case of complete alcoholysis, k = 0 in compound I. In
addition, the Si-X group in fragment V is simultaneously
converted to Si-W.

7
Ammonium ions, sodium ions or potassium ions can be used as the preferred metal ions. In this connection, the use of the corresponding sodium compound is particularly preferred.
Various sulfidation processes of the type described above are known and are described in JP 722 8588, US-A 54 05 985 and US-A 54 66 848.
The term "alky1" means both "straight-chain" and "branched" alkyl groups. The term "straight-chain alkyl group" means, for example, groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl; "branched alkyl group" means groups such as, for example, isopropyl or tert. butyl. The term halogen means fluorine, chlorine, bromine or iodine. The term "alkoxy" denotes groups such as, for example, methoxy, ethoxy, propoxy, butoxy, isopropoxy, isobutoxy or pentoxy.
Within the scope of the invention, "aryl" means phenyls, biphenyls, phenols or other benzenoid compounds substituted with (C1 - C6) alkyl-, (C1 - C6) alkoxy-, halogen, or with hetero atoms such as N, O, P or S. "Arylalkyl" means that the "aryls" indicated above are bonded to the relevant silicon atom by a (C1 - C6) alkyl chain, which for its part can be (C1 - C4) alkyl- or halogen-substituted. If "aryl" contains a hetero atom such as O or S, the (C1 - C6) alkyl chain can also form a bond with the silicon atom via the hetero atom.
Where substituents such as, for example, (C1 - C4) alkoxy are named, the number shown as a subscript indicates the total number of carbon atoms in the group.
The advantage of the multifunctional polyorganosiloxanes according to the invention is the sole use as silane coupling agents in silica-reinforced rubber mixtures, wherein they have at least one functional siloxyl group,


8
which is able to form a chemical and or physical bond with the hydroxyl groups at the surface of the silica particles, and contain at least one sulfur function, which is capable of chemical bonding to the polymer chains. As a result of the smaller proportion of alkoxy functions compared with prior art, the use of the multifunctional polyorganosiloxanes according to the invention also leads to a diminished release of alcohol during the mixing process.
The sulfur-functional polyorganosiloxanes according to the invention are particularly suitable for use in rubber
mixtures.
After the application of the process according to the invention, rubber mixtures which contain the sulfur-functionalised polyorganosiloxanes according to the invention as coupling agents or reinforcing additives and mouldings - in particular pneumatic tyres or tyre treads -resulting from a vulcanisation step exhibit a low rolling resistance with at the same time a good wet adhesion and high abrasion resistance.
The present invention also provides rubber mixtures which contain the sulfur-functional polyorganosiloxanes according to the invention. The rubber mixtures can also contain rubber, fillers, in particular also precipitated silica and optionally other rubber auxiliaries, and at least one sulfur-functional polyorganosiloxane according to the invention, in quantities of 0.1 to 15 wt.%, particularly preferably 5-10 wt.%, based on the quantity of the oxide filler used.
Where the sulfur-functional polyorganosiloxanes according to the invention are used in rubber mixtures, there are found to be advantages over the known mixtures as regards
the static and dynamic vulcanisation data.

9
The sulfur-functional polyorganosiloxanes according to the invention and the fillers are preferably added at composition temperatures of 80 to 200c C. But they can also be added later at lower temperatures (40 to 100°-C) for example, together with other rubber auxiliaries.
The sulfur-functional polyorganosiloxanes according to the invention can be introduced into the mixing process either in pure form or applied to an inert organic or inorganic support. Preferred supporting materials are silicas, natural or synthetic silicates, aluminium oxide or carbon blacks.
Suitable fillers for the rubber mixtures according to the
invention are:-
Carbon blacks: The carbon blacks to be used here are produced by the lampblack, furnace or channel black process and have BET surface areas of 20 to 200 m2/g. The carbon blacks may optionally also contain hetero atoms such as, for example, Si.
Highly disperse silicas, prepared, for example, by precipitation from solutions of silicates or flame hydrolysis of silicon halides, having specific surfaces of 5 to 1000, preferably 20 to 400 m2/g (BET surface area) and primary particle sizes of 10 to 400 run. The silicas may optionally also be present as mixed oxides with other metal oxides, such as the oxides of Al, Mg, Ca, Ba, Zn and titanium.
Synthetic silicates, such as aluminium silicate, alkaline-earth silicates, such as magnesium silicate or calcium silicate, having BET surface areas of 20 to 400 m2/g and primary particle diameters of 10 to 400 nm.
Natural silicates, such as kaolin and other naturally occurring silicas.

10
Glass fibres and glass fibre products (mats, strands) or glass microbeads.
It is preferable to use carbon blacks having BET surface areas of 20 to 400 m2/g or highly disperse silicas, prepared by precipitation from solutions of silicates, having BET surface areas of 20 to 400 m2/g in quantities of 5 to 150 parts by weight, in each case based on 100 parts rubber.
The above-mentioned fillers can be used alone or in a mixture. In a particularly preferred embodiment of the process, 10 to 150 parts by weight of light-coloured fillers, optionally together with 0 to 100 parts by weight carbon black, and 0.1 to 15 parts by weight, preferably 5 to 10 parts by weight, of a compound corresponding to formula I, in each case based on 100 parts by weight of the filler used, may be used for the preparation of the mixtures.
Besides natural rubber, synthetic rubbers are also suitable for preparing the rubber mixtures according to the invention. Preferred synthetic rubbers are described, for example, in: W. Hofmann, Kautschuktechnologie, Genter Verlag, Stuttgart 1980. They include:
Polybutadiene (BR) Polyisoprene (IR)
Styrene/butadiene copolymers having styrene contents of 1 to 60 wt.%, preferably 2 to 50 wt.% (SBR)
Isobutylene/isoprene copolymers (IIR)
Butadiene/acrylonitrile copolymers having acrylonitrile contents of 5 to 60, preferably 10 to 50 wt.% (NBR)

11
partially hydrogenated or completely hydrogenated NBR rubber (HNBR)
Ethylene/propylene/diene copolymers (EPDM)
and mixtures of these rubbers. In particular, anionically polymerised L-SBR rubbers having a glass temperature of above -50°'C as well as mixtures of these with diene rubbers are of interest for the production of tyres for automobiles.
The rubber vulcanisates according to the invention can also contain other rubber auxiliaries, such as reaction accelerators, antioxidants, heat stabilisers, light stabilisers, antiozonants, processing aids, plasticisers, tackifiers, blowing agents, dyes, waxes, extenders, organic acids, retarders, metal oxides and activators, such as triethanolamine, polyethylene glycol, hexanetriol, which are known in the rubber industry.
The rubber auxiliaries are used in conventional quantities, which depend inter alia on the intended use. Conventional quantities are, for example, quantities of 0.1 to 50 wt.%, based on rubber. The sulfur-functionalised polyorganosiloxanes can be used on their own as cross-linking agents. As a rule, the addition of other cross-linking agents is recommended. Other known cross-linking agents which can be used are sulfur or peroxides. The rubber mixtures according to the invention can in addition contain vulcanisation accelerators. Examples of suitable vulcanisation accelerators are mercaptobenzothiazoles, sulfenamides, guanidines, thiurams, dithiocarbamates, thioureas and thiocarbonates. The vulcanisation accelerators and sulfur or peroxides are used in quantities of 0.1 to 10 wt.%, preferably 0.1 to 5 wt.%, based on rubber.

12
The vulcanisation of the rubber mixtures according to the invention can take place at temperatures of 100 to 200 °'C, preferably 130 to 180 ° C, optionally under pressures of 10 to 200 bar. The mixing of the rubbers with the filler, optionally with the rubber auxiliaries and with the sulfur-functionalised polyorganosiloxanes according to the invention can be carried out in conventional mixing units, such as rolls, closed mixers and mixer-extruders. The rubber vulcanisates according to the invention are suitable for the production of mouldings, for example, for the production of pneumatic tyres, tyre treads, cable sheaths, hoses, drive belts, conveyor belts, roller coatings, tyres, shoe soles, sealing rings and damping elements.
Examples 1 to 3: Preparation of the sulfur-functionalised polyorganosiloxanes in two steps
Example 1:
First step:. A mixture consisting of 59.6 g {779.0 mmol) allyl chloride (commercial product of the firm Aldrich) and 1 ml of a 1% platinum solution in toluene (Karstedt catalyst) is added dropwise over a period of 2 h at 100° C To 100.0 g (38.9 mmol) silicone oil (Baysilone oil MH 15, commercial product of Bayer AG) corresponding to formula II with R1 = R2 = R3 = R4 = methyl, v = 40. In the course of this, the temperature rises to 140° C. On conclusion of the addition, the mixture is stirred for 30 min at 100°C. After the mixture has been cooled, 156.3 g (98% of the theoretical value) of the compound corresponding to formula IV, with R1 = R2 = R3 = R4 = methyl, X = Cl, Y = CH2-CH2-CH3, Z = CH2-CH2-CH2, m = 10, n = 10, p = 10 is obtained as a light yellow liquid. lH NMR (CDC13) : 5 -0.2 - 0.2 (m, 138 H, Si-CH3), 0.39 (m, 20 H, CH2~CH2-CH3) , 0.55 (m, 20 H, CH2-CH2-CH2-C1) , 0.85 (m.

13
30 H, CH2-CH2-CH3) , 1.28 (m, 20 H, CH2-CH2-CH3) , 1.68 (s, 20 H, CH2-CH2-CH2-Cl) , 3.35 (s, 20 H, CH2-CH2-CH2-C1) , 4.58 (s, 1H-29Si) = 250.1 Hz, 10 H, Si-H) .
Second step: 102.2 g (24.9 mmol) of the compound corresponding to formula IV with R1 = R2 = R3 = R4 = methyl, X = Cl, Y = CH2-CH2-CH3, Z = CH2-CH2-CH2, m = 10, n = 10, p = 10 is added dropwise to a suspension of 57.1 g {327.9 mmol) Na2S4 in 3 00 ml ethanol (W = ethoxy) at room temperature over a period of 45 min. During the dropwise addition hydrogen is released and the temperature rises to 45oC. At the same time, a solid is precipitated out. On conclusion of the addition, stirring is continued for 3 h at 80°C (refluxing). The solution is then allowed to cool and is filtered off from the NaCl formed. After the removal of the solvent by distillation, 75.0 g (65% of the theoretical value) of the compound corresponding to formula I with R1 = R2 = R3 = R4 = methyl, A = Sx, W = ethoxy, Y = CH2-CH2-CH3, Z = CH2-CH2-CH2, k = 0, m = 20, n = 10, p = 10 remains.
1H NMR (CDC13) : -0.2 - 0.2 (m, 138 H, Si-CH3), 0.42 (m, 20 H, CH2-CH2-CH3) , 0.58 (m, 20 H, CH2-CH2-CH2-S) , 0.88 (m, 30 H, CH2-CH2-CH3) , 1.08 '(s, 60 H, Si-O-CH2-CH3) , 1.30 (m, 20 H, CH2-CH2-CH3) , 1.70 (s, 20 H, CH2-CH2-CH2-S) , 2.5 - 2.9 (m, 20 H, CH2-CH2-CH2-S) , 3.62 (s, 3J(1H-29Si) = 150.0 Hz, 40 H, Si-O-CH2-CH3) .
Example 2:
First step: A mixture consisting of 12.9 g (169.0 mmol) allyl chloride and 220 l of a 1% platinum solution in toluene (Karstedt catalyst) is added dropwise over a period of 30 min at 100 C to 216.8 g (84.5 mmol) silicone oil (Baysilone oil MH 15) corresponding to formula II with R1 = R2 = R3 = R4 = methyl, v = 40. In the course of this, the temperature rises to 130 °-C. On conclusion of the addition, the mixture is stirred for 1 h at 100° C. After the mixture has been cooled, 226.9 g (99% of the

14
theoretical value) of the compound corresponding to
formula IV, with R1 = R2 = R3 = R4 = methyl, X = Cl, Y = CH2-CH2-CH3, Z = CH2-CH2-CH2, m = 37, n = 1, p = 1 is obtained as a light yellow liquid.
1H NMR (CDCl3) : 5 -0.2 - 0.1 (m, 138 H, Si-CH3), 0.36 (m, 2 H, CH2-CH2-CH3) , 0.48 (m, 2 H, CH2-CH2-CH2-C1) , 0.76 (t, 3J(1H-1H) = 8.3 Hz, 3 H, CH2-CH2-CH3) , 1.20 (m, 2 H, CH2-CH2-CH3), 1.62 {m, 2 H, CH2-CH2-CH2-C1) , 3.28 (m, 2 H, CH2-CH2-CH2-Cl), 4.52 (s, 1J(1K-29Si) = 250.1 Hz, 37 H, Si-H) .
Second step: 50.0 g (18.4 mmol) of the compound corresponding to formula IV with R1 = R2 = R3 = R4 = methyl, X = Cl, Y = CH2-CH2-CH3, Z = CH2-CH2-CH2/ m = 37, n = 1, p = 1 is added dropwise to a suspension of 3.2 g (18.4 mmol) Na2S4 in 160 ml ethanol (W = ethoxy) at room temperature over a period of 1 h. During the dropwise addition hydrogen is released and the temperature rises to 50°C. At the same time, a solid is precipitated out. On conclusion of the addition, stirring is continued for 4 h at 80°C (refluxing). The solution is then allowed to cool and is filtered off from the NaCl formed. After the removal of the solvent by distillation, 70.4 g (86% of the theoretical value) of the compound corresponding to formula I with R1 = R2 = R3 = R4 = methyl, A = Sx, W = ethoxy, Y = CH2-CH2-CH3, Z = CH2-CH2-CH2, k = 0, m = 38, n = 1, p = 1 remains.
1H NMR (CDCl3) : 8 -0.2 - 0.2 (m, 138 H, Si-CH3), 0.44 (m, 2 H, CH2-CH2-CH3) , 0.56 (m, 2 H, CH2-CH2-CH2-S) , 0.82 (m, 3 H, CH2-CH2-CH3) , 1.08 (s, 114 H, Si-O-CH2-CH3) , 1.28 (m, 2 H, CH2-CH2-CH3) , 1.70 (s, 2 H, CH2-CH2-CH2-S) , 2.5 - 2.9 (m, 2 H, CH2-CH2-CH2-S) , 3.64 (m, 76 H, Si-O-CH2-CH3) -

15 Example 3:
First step: A mixture consisting of 59.6 g (779.0 mmol)
allyl chloride and 1 ml of a 1% platinum solution in
toluene (Karstedt catalyst) is added dropwise over a
period of 60 min at 110° C to 200.0 g (77.9 mmol) silicone
oil (Baysilone oil MH 15) corresponding to formula II with
R1 = R2 = R3 = R4 = methyl, v = 40. In the course of this,
the temperature rises to 130°C. On conclusion of the
addition, the mixture is stirred for 1 h at 110° C. After
the mixture has been cooled, 257.2 g (99% of the
theoretical value) of the compound corresponding to
formula IV with R1 = R2 = R3 = R4 = methyl, X = Cl, Y = CH2-
CH2-CH3, 2 = CH2-CH2-CH2, m = 25, n = 5, p = 5 is obtained
as a light yellow liquid.
1H NMR (CDCI3) : 5 -0.2 - 0.2 (m, 138 H, Si-CH3), 0.34 (m,
10 H, CH2-CH2-CH3) , 0.46 (m, 10 H, CH2-CH2-CH2-Cl) , 0.82 (m,
15 H, CH2-CH2-CH3) , 1.25 (m, 10 H, CH2-CH2-CH3) , 1.68 (m, 10
H, CH2-CH2-CH2-Cl) , 3.37 (m, 10 H, CH2-CH2-CH2-Cl) , 4.56 (s,
1J(1H-29Si) = 249.5 Hz, 25 H, Si-H) .
Second step: 100.0 g (30.0 mmol) of the compound corresponding to formula IV with R1 = R2 = R3 = R4 = methyl, X = Cl, Y = CH2-CH2-CH3, 2 = CH2-CH2-CH2, m = 25, n = 5, p = 5 is added dropwise to a suspension of 26.2 g (150.0 mmol) Na2S4 in 300 ml ethanol (W = ethoxy) at room temperature over a period of 45 min. During the dropwise addition hydrogen is released and the temperature rises to 50°C. At the same time, a solid is precipitated out. On conclusion of the addition, stirring is continued for 6.5 h at 80°'C (refluxing) . The solution is then allowed to cool and is filtered off from the NaCl formed. After the removal of the solvent by distillation, 117.7 g (87.9% of the theoretical value) of the compound corresponding to formula I with Ra = R2 = R3 = R4 = methyl, A = Sx, W = ethoxy, Y = CH2-CH2-CH3, Z = CH2-CH2-CH2, k = 7, m = 22, n = 5, p = 6 remains.

16
1H NMR (CDC13) : 5 -0.2 - 0.2 (m, 138 H, S1-CH3), 0.42 (m, 10 H, CH2-CH2-CH3) , 0.54 (m, 12 H, CH2-CH2-CH2-S) , 0.85 (m, 15 H, CH2-CH2-CH3) , 1.08 (s, 66 H, Si-O-CH2-CH3) , 1.28 (m, 10 H, CH2-CH2-CH3) , 1-70 (s, 12 H, CH2-CH2-CH2-S) , 2.5 - 2.9 (m, 12 H, CH2-CH2-CH2-S) , 3.65 (m, 44 H, Si-O-CH2-CH3) , 4.60 (s, 1J(1H-29Si) = 249.6 Hz, 7 H, Si-H).
Examples of use: Preparation of the rubber mixtures and vulcanisates
General instructions for procedure
The formulation used for the rubber mixtures is given in Table 1. There the unit phr denotes per cent by weight, based on 100 parts of the crude rubber used.


17
Table 1

The polymer VSL 5025-1 is an SBR copolymer which is polymerisable in solution, a product of Bayer AG, having a styrene content of 25 wt.% and a butadiene content of 75 wt.%. Of the butadiene, 73 % is 1,2 bonded, 10 % is cis 1,4 bonded and 17 % is trans 1,4 bonded. The copolymer contains 37.5 phr oil and has a Mooney viscosity (ML l+4/100°C) of 50 ±4.

18
The polymer Buna CB 24 is a cis 1,4 polybutadiene (Neodymium type), a product of Bayer AG, having cis 1,4-content of 97 %, a trans 1,4-content of 2 %, a 1,2-content of 1 % and a Mooney viscosity of 44 ±5.
The HD silica Ultrasil 7000, a product of Degussa AG, has a BET surface area of 180 m2.
The silane bis(3-[triethoxysilyl]propyl)disulfane (TESPD) is a silane having a disulfane content of >80% and a polysulfane content S{x>4) of <4%. This substance can be obtained by a process according to Patent D 195 41 404. The silane propyltriethoxysilane (PTES) is an alkylsilane which is sold by Degussa AG under the trade name Si 203.
Naftolene ZD, a product of Chemetall, is used as an aromatic oil. Vulkanox 4020 is a 6PPD from Bayer AG and Protektor G35P is an antiozonant wax from HB-Fuller GmbH. Vulkacit D (DPG) and Vulkacit CZ (CBS) are commercial products of Bayer AG.


19
The rubber mixture is prepared in three steps in a closed mixer, in accordance with the following tabulated schedule.
Table 2:

20

The general process for preparing rubber mixtures and their vulcanisates is described in "Rubber Technology-Handbook", W. Hofmann, Hanser Verlag, 1994.
The vulcanisation temperature is 165°C.

21
The testing of the rubber is carried out in accordance with the methods of test shown in Table 3.
Table 3

Examples 4 to 7
Examples 4 to 7 are carried out in accordance with the general instructions given above; the mixture 4 (silane coupling agent PTES) and the mixture 7 {silane coupling agent TESPD) are reference examples from prior art.
In a variation from the Reference Examples 4 and 7, the sulfur-functionalised silicone oil as in Example 2 is introduced into the mixture from Example 5 and the silicone oil as in Example 3 is mixed into Example 6.

22
The data obtained from the rubber tests on the crude mixture and the vulcanisate are as listed in Table 4.
Table 4:

From the low Mooney viscosities of mixtures 5 and 6 in Table 4, it is clear that the claimed silicone oils are just as able to render the silica water repellent as are the silanes in the reference mixtures 4 and 7 from prior art. It can also be seen that, with increasing amounts of sulfur functionality in the silicone oils, the Shore A hardness and the yield strengths are definitely increased compared with those in Reference Example 4, and in Example 6 the level of Example 7 is almost achieved.

23
Moreover, conspicuous in the functionalised silicone oil in Example 6 is an advantageously high tan (0°C) value, which correlates with an improved wet skid resistance; without loss in the tan (60°C) value, which is associated with the rolling resistance.
Compared with the Reference Example 7, the rapid vulcanisation kinetics in the functionalised silicone oils are especially advantageous. Here one may mention in particular the short t90%-tl0% times and the higher reaction constants k(V) (first order reaction).


-24-
WE CLAIM:
1. Process for the preparation of the sulfur-functional-paly- organosilaxanes corresponding to the general formula I

wherein R1 , R2 , R3 , R4 , independently of one another,
denote
H,(C1 -C4) alkyl, (C1 -C4) alkoxy, (C1 -C4) halaalkoxy, ((C1 -C4)) haloalkyl, ^ phenyl, aryl or aralkyl and
W denotes a group which can bond to the silica and
preferably can be ((C1 -C4)) alkoxy or
((C1 -C4)) haloalkoxy and
Y denotes alkyl, haloalkyl, phenyl, aryl or aralkyl
and
Z denotes an alkylidene group having 0-6 carbon
atoms and

-25-
A denotes a group which can bond with at least one
elastomer of the rubber mixture:
for q = 1 preferably a mercapto group (SH) and thio-
cyanate group (SCN) and for q = 2 a disulfide 3 and k and n
can equall.
characterized in that the compounds corresponding to the general formula IV

wherein R1 , R2 , R3 ,R4 , Y, Zm, n and p have the
meanings given herein before cl aim 1, X can be halogen,
are reacted with MSH, MSCN or MS, wherein M
2 x can be a metal ion and x on statiscal average can be
a number between 2 and 10, or with ti S and S,
2 wherein M is a metal ion, in an alcohol W-H, wherein

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W has the meaning given hereinbefore,, optionally at
reaction temperatures between 20o C and 150o C
and optionally under catalytic conditions at normal pressure, to form compounds corresponding to the general formula I.
wherein R1 , R 2, R 3, R4 , independently of one another,
denote
2. Process as claimed in claim I wherein the metal ion is an
ammonium ion, sodium ion or potassiua ion.
3. Process for the preparation of rubber mixtures wherein in
addition to the rubber, at least one other filler and a sulfur-
functional ised polyorganosiloxane as clamied in claim 1 are used.
4. Process for the preparation of the sulfur-functional poly-
organosiloxanes corresponding to the general formula I,


H,(C1-C4) alkyl, (C1-C4) alkoxy,
(C1-C4) haloalkoxy, (C1-C4) halo-
alkyl,phenyl, aryl or aralkyl and
W denotes a group which can bond to the silica and
preferably can be (C1-C4) alkoxy or (C1-C4 )
haloalkoxy and
Y denotes alkyl, haloalkyl, phenylT aryl or aralkyl
2 denotes a -CH2CH2CH2 group and
A denotes a group which can bond with at least one elastomer of the rubber mixture:
wherein R , R , R ,R , Y, Z, m, n and p have the
meanings given in claim 1, X can be halogen, are reacted
for q = 1 group (SCN) and for q = 2 a disulfide (S2) and a polysulfide (Sx) with X = 2 - 10 and H denotes hydrogen and the sum of k+m+n+p> 3 and k and n can equal O wherein the compounds corresponding to the general formula IV


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with MSH, MSCN, or M 5 , wherein M can be a
metal ion and x on statistical average can be a number
between 2 and 10, or with M S and S, wherein M is a
2 metal ion , in an alcohol W-H, wherein W has the meaning
given in claim 1, optionally at reaction temperatures
o o between 20 C and 150 C and optionally under catalytic
conditions at normal pressure, to form compounds corresponding to the general formula I.
This invention relates to a process for the preparation of the sulfur-functional poly-organosiloxanes corresponding to the general formula I

wherein R1 , R2 , R3 , R4 , independently of one another,
denote
H,(C1-C4) alkyl, (C1-C4)alkoxy,
(C1-C4)haloalkoxy, (C1-C4) haloalkyl,
phenyl, aryl or aralkyl and
W denotes a group which can bond to the si1ica and
preferably can be (C1-C4) alkoxy or
(C1-C4) haloalkoxy and
Y denotes alkyl, haloalkyl, phenyl, aryl or aralkyl
and
2 denotes an alkylidene group having 0 - 6 carbon
atoms and

A denotes a group which can bond with at least one elastomer of the rubber mixture: for q = 1 preferably a mercapto group (SH) and thio-
cyanate group (SCN) and for q = 2 a disulfide (S2 )
and a polysulfide (Sx) with x = 2 - 10 and H denotes
hydrogen and the sum of k+m+n+p > 3 and k and n
can equal 0,
characterized in that the compounds corresponding to the general formula IV

wherein R1 , R2 , R3 ,R4 , Y, Zm, n and p have the
meanings given hereinbefore, X can be halogen,
are reacted with MSH, MSCN or M S , wherein M
2 x can be a metal ion and x on statiscal average can be
a number between 2 and 10, or with W S and S,
2 wherein M is a metal ion, in an alcohol W-H, wherein
W has the meaning given hereinbefore, optionally at
reaction temperatures between 20 oC and 150o C
and optionally under catalytic: conditions at normal pressure, to form compounds corresponding to the general formula I.