CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is the national stage of international application PCT/EP2018/081486, filed on Nov. 16, 2018, and claims the benefit of the filing date of German Appl. No. 10 2017 221 269.1, filed on Nov. 28, 2017.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Inventions described in the present application were developed within the scope of a joint research agreement between the applicant and Continental Reifen Deutschland GmbH.

The invention relates to silane mixtures and to processes for preparation thereof.

EP 0670347 and EP 0753549 disclose rubber mixtures comprising at least one crosslinker, a filler, optionally further rubber auxiliaries and at least one reinforcing additive of the formula
R1R2R3Si—X1—(—Sx—Y—)m—(—Sx—X2—SiR1R2R3)n.

JP2012149189 discloses the silane of the formula (R1O)lR2(3-l)Si—R3—(SmR4)n—S—R5with R5=—C(═O)—R6

R6=C1-C20.

In addition, EP 1375504 discloses silanes of the formula
(R1O)(3-p)(R2)pSi—R3—Sm—R4—(Sn—R4)q—Sm—R3—Si(R2)p(OR1)(3-p).

WO 2005/059022 discloses rubber mixtures comprising a silane of the formula
[R2R3R4Si—R5—S—R6—R7—]R1.

Additionally known are rubber mixtures comprising a bifunctional silane and a further silane of the formula (Y)G(Z) (WO 2012/092062) and rubber mixtures comprising bistriethoxysilylpropyl polysulfide and bistriethoxysilylpropyl monosulfide (EP1085045).

EP 1928949 discloses a rubber mixture comprising the silanes (H5C2O)3Si—(CH2)3—X—(CH2)6—S2—(CH2)6—X—(CH2)3—Si(OC2H5)3and/or (H5C2O)3Si—(CH2)3—X—(CH2)10—S2—(CH2)6—X—(CH2)10—Si(OC2H5)3and (H5C2O)3Si—(CH2)3—Sm—(CH2)3—Si(OC2H5)3.

It is an object of the present invention to provide silane mixtures having improved rolling resistance and improved fracture energy density in rubber mixtures compared to silanes known from the prior art.

The invention provides a silane mixture comprising a silane of the formula I
(R1)y(R2)3-ySi—R3—(S—R4)n—Sx—R5(I)
and a silane of the formula II
(R1)y(R2)3-ySi—R3—S—R4—S—R3—Si(R1)y(R2)3-y(II)

where R1are the same or different and are C1-C10-alkoxy groups, preferably methoxy or ethoxy groups, phenoxy group, C4-C10-cycloalkoxy groups or alkyl polyether group O—(R6—O)r—R7where R6are the same or different and are a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group, preferably —CH2—CH2—, r is an integer from 1 to 30, preferably 3 to 10, and R7is unsubstituted or substituted, branched or unbranched monovalent alkyl, alkenyl, aryl or aralkyl groups, preferably a C13H27-alkyl group,

R2is the same or different and is C6-C20-aryl groups, preferably phenyl, C1-C10-alkyl groups, preferably methyl or ethyl, C2-C20-alkenyl group, C7-C20-aralkyl group or halogen, preferably Cl,

R3are the same or different and are a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group, preferably C1-C20, more preferably C1-C10, even more preferably C2-C8, especially preferably CH2CH2and CH2CH2CH2,

R4are the same or different and are a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group, preferably C1-C20, more preferably C1-C10, even more preferably C2-C7, especially preferably (CH2)6,

x is an integer from 1 to 10, preferably 1 to 4, more preferably 1 or 2,

when x is 1 R5is hydrogen or a —C(═O)—R8group with R8=hydrogen, a C1-C20 alkyl group, preferably C1-C17, C6-C20-aryl groups, preferably phenyl, C2-C20-alkenyl group or a C7-C20-aralkyl group and n is 0, 1, 2 or 3, preferably 1,

when x is 2 to 10 R5is —(R4—S)n—R3—Si(R1)y(R2)3-yand n is 1, 2 or 3, preferably 1, and y are the same or different and are 1, 2 or 3,

and the molar ratio of silane of the formula I to silane of the formula II is 20:80-90:10, preferably 25:75-90:10, more preferably 30:70-90:10, most preferably 35:65-90:10.

Preferably, the silane mixture may comprise a silane of the formula I
(R1)y(R2)3-ySi—R3—(S—R4)n—Sx—R5(I)
and a silane of the formula II
(R1)y(R2)3-ySi—R3—S—R4—S—R3—Si(R1)y(R2)3-y(II)

where n is 1 and R1, R2, R3, R4, R5, x and y have the same definition as described above.

The silane mixture according to the invention may comprise further additives or consist solely of silanes of the formula I and silanes of the formula II.

The silane mixture according to the invention may comprise oligomers that form as a result of hydrolysis and condensation of the silanes of the formula I and/or silanes of the formula II.

The silane mixture according to the invention may have been applied to a support, for example wax, polymer or carbon black. The silane mixture according to the invention may have been applied to a silica, in which case the binding may be physical or chemical.

R3and R4may independently be —CH2—, —CH2CH2—, —CH2CH2CH2—, —CH2CH2CH2CH2—, —CH(CH3)—, —CH2CH(CH3)—, —CH(CH3)CH2—, —C(CH3)2—, —CH(C2H5)—, —CH2CH2CH(CH3)—, —CH(CH3)CH2CH2—, —CH2CH(CH3)CH2—, —CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2—,—CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2—, —CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2— or



R1may preferably be methoxy or ethoxy.

Silanes of the formula I may preferably be:

(EtO)3Si—CH2—S2—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S2—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S2—(CH2)3—Si(OEt)3,

(EtO)3Si—CH2—S4—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S4—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S4—(CH2)3—Si(OEt)3,

(EtO)3Si—CH2—S—(CH2)—S2—(CH2)—S—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S—(CH2)—S2—(CH2)—S—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S—(CH2)—S2—(CH2)—S—(CH2)3—Si(OEt)3,

(EtO)3Si—CH2—S—(CH2)2—S2—(CH2)2—S—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S—(CH2)2—S2—(CH2)2—S—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S—(CH2)2—S2—(CH2)2—S—(CH2)3—Si(OEt)3,

(EtO)3Si—CH2—S—(CH2)3—S2—(CH2)3—S—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S—(CH2)3—S2—(CH2)3—S—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S—(CH2)3—S2—(CH2)3—S—(CH2)3—Si(OEt)3,

(EtO)3Si—CH2—S—(CH2)4—S2—(CH2)4—S—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S—(CH2)4—S2—(CH2)4—S—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S—(CH2)4—S2—(CH2)4—S—(CH2)3—Si(OEt)3,

(EtO)3Si—CH2—S—(CH2)5—S2—(CH2)5—S—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S—(CH2)5—S2—(CH2)5—S—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S—(CH2)5—S2—(CH2)5—S—(CH2)3—Si(OEt)3,

(EtO)3Si—CH2—S—(CH2)6—S2—(CH2)6—S—CH2—Si(OEt)3,

(EtO)3Si—(CH2)2—S—(CH2)6—S2—(CH2)6—S—(CH2)2—Si(OEt)3,

(EtO)3Si—(CH2)3—S—(CH2)6—S2—(CH2)6—S—(CH2)3—Si(OEt)3.

(EtO)3Si—(CH2)3—S_C(═O)—CH3,

(EtO)3Si—(CH2)3—S_C(═O)—C2H5,

(EtO)3Si—(CH2)3—S_C(═O)—C3H7,

(EtO)3Si—(CH2)3—S—C(═O)—C4H5,

(EtO)3Si—(CH2)3—S—C(═O)—C5H11,

(EtO)3Si—(CH2)3—S_C(═O)—C6H13,

(EtO)3Si—(CH2)3—S_C(═O)—C7H15,

(EtO)3Si—(CH2)3—S_C(═O)—C9H19,

(EtO)3Si—(CH2)3—S_C(═O)—C11H23,

(EtO)3Si—(CH2)3—S_C(═O)—C13H27,

(EtO)3Si—(CH2)3—S_C(═O)—C15H31,

(EtO)3Si—(CH2)3—S_C(═O)—C17H35,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—CH3,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C2H5,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C3H7,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C4H9,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C5H11,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C6H13,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C7H15,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C9H19,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C11H23,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C13H27,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C15H31,

(EtO)3Si—(CH2)3—S—(CH2)—S_C(═O)—C17H35,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—CH3,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C2H5,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C3H7,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C4H9,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C5H11,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C6H13,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C7—H15,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C9H19,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C11H23,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C13H27,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C15H31,

(EtO)3Si—(CH2)3—S—(CH2)2—S_C(═O)—C17H35,

(EtO)3Si—(CH2)3—S—(CH2)3—S_C(═O)—CH3,

(EtO)3Si—(CH2)3—S—(CH2)3—S_C(═O)—C2H5,

(EtO)3Si—(CH2)3—S—(CH2)3—S_C(═O)—C3H7,

(EtO)3Si—(CH2)3—S—(CH2)3— S_C(═O)—C4H9,

(EtO)3Si—(CH2)3—S—(CH2)3— S_C(═O)—C5H11,

(EtO)3Si—(CH2)3—S—(CH2)3— S_C(═O)—C6H13,

(EtO)3Si—(CH2)3—S—(CH2)3— S_C(═O)—C7H15,

(EtO)3Si—(CH2)3—S—(CH2)3— S_C(═O)—C9H19,

(EtO)3Si—(CH2)3—S—(CH2)3—S_C(═O)—C11H23,

(EtO)3Si—(CH2)3—S—(CH2)3—S_C(═O)—C13H27,

(EtO)3Si—(CH2)3—S—(CH2)3—S_C(═O)—C15H31,

(EtO)3Si—(CH2)3—S—(CH2)3—S_C(═O)—C17H35,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—CH3,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C2H5,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C3H7,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C4H9,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C5H11,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C6H13,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C7H15,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C9H19,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C11H23,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C13H27,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C15H31,

(EtO)3Si—(CH2)3—S—(CH2)6—S_C(═O)—C17H35,

Especially preferred is the silane of the formula I

(EtO)3Si—(CH2)3—S—(CH2)6—S2—(CH2)6—S—(CH2)3—Si(OEt)3, (EtO)3Si—(CH2)3—S—(CH2)6—S—C(═O)—CH3, (EtO)3Si—(CH2)3—S—(CH2)6—S—C(═O)—C7H15and (EtO)3Si—(CH2)3—S—(CH2)6—S—C(═O)—C17H35.

Silanes of the formula II may preferably be:

(EtO)3Si—(CH2)—S—(CH2)—Si(OEt)3,

(EtO)3Si—(CH2)2—S—(CH2)2Si(OEt)3,

(EtO)3Si—(CH2)3—S—(CH2)3Si(OEt)3,

(EtO)3Si—(CH2)4—S—(CH2)4Si(OEt)3,

(EtO)3Si—(CH2)5—S—(CH2)5Si(OEt)3,

(EtO)3Si—(CH2)6—S—(CH2)6Si(OEt)3,

(EtO)3Si—(CH2)7—S—(CH2)7Si(OEt)3,

(EtO)3Si—(CH2)8—S—(CH2)8Si(OEt)3,

(EtO)3Si—(CH2)9—S—(CH2)9Si(OEt)3,

(EtO)3Si—(CH2)19—S—(CH2)10Si(OEt)3,

Especially preferred is the silane of the formula II

(EtO)3Si—(CH2)3—S—(CH2)3Si(OEt)3.

Very particular preference is given to a silane mixture of (EtO)3Si—(CH2)3—S—(CH2)6—S2—(CH2)6—S—(CH2)3—Si(OEt)3, (EtO)3Si—(CH2)3—S—(CH2)6—S—C(═O)—CH3, (EtO)3Si—(CH2)3—S—(CH2)6—S—C(═O)—C7H15or (EtO)3Si—(CH2)3—S—(CH2)6—S—C(═O)—C17H35and (EtO)3Si—(CH2)3—S—(CH2)3Si(OEt)3.

The present invention further provides a process for preparing the silane mixture according to the invention, which is characterized in that the silane of the formula I
(R1)y(R2)3-ySi—R3—(S—R4)n—Sx—R5(I)
and a silane of the formula II
(R1)y(R2)3-ySi—R3—S—R4—S—R3—Si(R1)y(R2)3-y(II)

where R1, R2, R3, R4, R5, n, x and y have the definition given above

are mixed in a molar ratio of 20:80-90:10, preferably 25:75-90:10, more preferably 30:70-90:10, most preferably 35:65-90:10.

Preferably, a silane of the formula I
(R1)y(R2)3-ySi—R3—(S—R4)n—Sx—R5(I)
and a silane of the formula II
(R1)y(R2)3-ySi—R3—S—R4—S—R3—Si(R1)y(R2)3-y(II)

where R1, R2, R3, R4, R5, x and y have the definition given above and n is 1 can be mixed.

The process according to the invention can be conducted with exclusion of air. The process according to the invention can be conducted under protective gas atmosphere, for example under argon or nitrogen, preferably under nitrogen.

The process according to the invention can be conducted at standard pressure, elevated pressure or reduced pressure. Preferably, the process according to the invention can be conducted at standard pressure.

Elevated pressure may be a pressure of 1.1 bar to 100 bar, preferably of 1.1 bar to 50 bar, more preferably of 1.1 bar to 10 bar and very preferably of 1.1 to 5 bar.

Reduced pressure may be a pressure of 1 mbar to 1000 mbar, preferably 250 mbar to 1000 mbar, more preferably 500 mbar to 1000 mbar.

The process according to the invention can be conducted between 20° C. and 100° C., preferably between 20° C. and 50° C., more preferably between 20° C. and 30° C.

The process according to the invention can be conducted in a solvent, for example methanol, ethanol, propanol, butanol, cyclohexanol, N,N-dimethylformamide, dimethyl sulfoxide, pentane, hexane, cyclohexane, heptane, octane, decane, toluene, xylene, acetone, acetonitrile, carbon tetrachloride, chloroform, dichloromethane, 1,2-dichloroethane, tetrachloroethylene, diethyl ether, methyl tert-butyl ether, methyl ethyl ketone, tetrahydrofuran, dioxane, pyridine or methyl acetate, or a mixture of the aforementioned solvents. The process according to the invention can preferably be conducted without solvent.

The silane mixture according to the invention can be used as adhesion promoter between inorganic materials, for example glass beads, glass flakes, glass surfaces, glass fibres, or oxidic fillers,

preferably silicas such as precipitated silicas and fumed silicas,

and organic polymers, for example thermosets, thermoplastics or elastomers, or as crosslinking agents and surface modifiers for oxidic surfaces.

The silane mixture according to the invention can be used as coupling reagents in filled rubber mixtures, examples being tyre treads, industrial rubber articles or footwear soles.

Advantages of the silane mixtures according to the invention are improved rolling resistance and improved reinforcement in rubber mixtures.

