Liquid sulfur-containing oligosiloxanes and their use in rubber mixtures

A process for the preparation of sulfur-containing siloxanes comprising the step of reacting siloxanes of the general formula (II)

• wherein
• R and R′ independently of one another represent a C1-C24-alkyl radical or a C6-C24-aryl radical,
• R′″ represents R, OR or H, wherein the radicals R and R′″ can be identical or different,
• RIV represents R, SiR3′″ or H, wherein the radicals R, R′″ and RIV can be identical or different, and
• RV represents a limonyl radical, an ethylenecyclohexene radical, an ethylenenorbornenyl radical or norbornylethylidene or norbornylvinyl radical, a C4-C24-alkenyl radical or a bicyclopentenyl radical and
• the sum of x and y is a number In the range from 2 to 200, with the proviso that always only one radical RV is present per molecule,
• with sulfur or with sulfur and hydrogen sulfide, in each case in the presence of a catalyst, wherein said sulfur-containing siloxanes are of the general formula (I)
• wherein
• R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C4-C24-alkyl radical or a sulfur-containing dicyclopentyl radical, wherein the sulfur containing radical does not carry SH,
• with the proviso that always only one radical R′ is present per siloxane molecule.

A mixture comprising i) sulfur-containing siloxanes of the general formula (I)

• wherein
• R and R″ independently of one another represent a C1-C24-alkyl radical or a C6-C24-aryl radical,
• R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C4-C24-alkyl radical or a sulfur-containing dicyclopentyl radical, wherein the sulfur containing radical does not carry SH,
• R′″ represents R, OR or H, wherein the radicals R and R′″ can be identical or different,
• RIV represents R, SiR3′″ or H, wherein the radicals R, R′″ and RIV can be identical or different,
• the sum of x and y is a number in the range from 2 to 200,
• with the proviso that always only one radical R′ is present per siloxane molecule and
• siloxanes and/or sulfur-containing silanes.

Silica-containing rubber mixtures comprising sulfur-containing siloxanes of the general formula (I)

• wherein
• R and R″ independently of one another represent a C1-C24-alkyl radical or a C6-C24-aryl radical,
• R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C4-C24-alkyl radical or a sulfur-containing dicyclopentyl radical, wherein the sulfur containing radical does not carry SH,
• R″′ represents R, OR or H, wherein the radicals R and R′″ can be identical or different,
• RIV represents R, SiR3′″ or H, wherein the radicals R, R′″ and RIV can be identical or different,
• the sum of x and y is a number in the range from 2 to 200,
• with the proviso that always only one radical R′ is present per siloxane molecule.

Sulfur-containing siloxanes of the general formula (Ia), comprising the structural units (K), (L), (M), (N)

• wherein
• R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C4-C24-alkyl radical or a sulfur-containing dicyclopentyl radical, wherein the sulfur containing radical does not carry SH,
• RVI represents, C6-C24-alkyl radical, a C1-C24-aryl radical, a C1-C24-alkoxy radical, a C6-C24-aryloxy radical, H or OH,
• RVII, RVIII, RIX, RX, RXI and RXII independently of one another represent a C1-C24-alkyl radical, a C6-C24-aryl radical or H,
• the sum of x and y represents an integer in the range from 2 to 200 and w and z each independently of one another can be an integer between 0 and 100,
• with the proviso that always only one radical R′ is present per siloxane molecule.

A process for preparing sulfur-containing siloxanes of the general formula (Ia), wherein the sulfur containing siloxanes comprise the structural units (K), (L), (M), (N)

• wherein
• R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C4-C24-alkyl radical or a sulfur-containing dicyclopentyl radical,
• RVI represents a C1-C24-alkyl radical, a C6-C24-aryl radical, a C1-C24-alkoxy radical, a C6-C24-aryloxy radical, H or OH,
• RVII, RVIII, RIX, RX, RXI and RXII independently of one another represent a C1-C24-alkyl radical, a C6-C24-aryl radical or H,
• the sum of x and y represents an integer in the range from 2 to 200 and w and z each independently of one another can be an integer between 0 and 100,
• with the proviso that always only one radical R′ is present per siloxane molecule,
• comprising the step of reading i) siloxanes of the general formula (IIa) containing structural units (K′), (L), (M), (N)
• wherein
• RV represents a limonyl radical, an ethylenecyclohexene radical, an ethylenenorbornenyl radical or a norbornylethylidene or norbornylvinyl radical, a C4-C24-alkenyl radical or a bicyclopentenyl radical and
• with the proviso that always only one radical RV is present per molecule,
• with ii) sulfur or sulfur and hydrogen sulfide in the presence of a catalyst.

A mixture comprising:

• i) sulfur-containing siloxanes of the general formula (Ia), comprising the structural units (K), (L), (M), (N)
• wherein
• R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C4-C24-alkyl radical or a sulfur-containing dicyclopentyl radical, wherein the sulfur containing radical does not carry SH,
• RVI represents a C1-C24-alkyl radical, a C6-C24-aryl radical, a C1-C24-alkoxy radical, a C6-C24-aryloxy radical, H or OH,
• RVII, RVIII, RIX, RX, RXI and RXII independently of one another represent a C1-C24-alkyl radical, a C6-C24-aryl radical or,
• the sum of x and y represents an integer in the range from 2 to 200 and wand z each independently of one another can be an integer between 0 and 100,
• with the proviso that always only one radical R′is present per siloxane molecule;
• and
• ii) siloxanes and/or sulfur-containing silanes.

Silica-containing rubber mixtures comprising sulfur-containing siloxanes of the general formula (Ia), comprising the structural units (K), (L), (M), (N)

• wherein
• R′ represents a sulfur-containing 2-(p-methylcyclohexyl)propyl radical, a sulfur-containing 2-cyclohexylethyl radical, a sulfur-containing 2-norbornylethyl radical, a sulfur-containing 2-norbornylpropyl radical, a sulfur-containing C4-C24-alkyl radical or a sulfur-containing dicyclopentyl radical, wherein the sulfur containing radical does not carry SH,
• RVI represents a C1-C24-alkyl radical, a C6-C24-aryl radical, a C1-C24-alkoxy radical, a C6-C24-aryloxy radical, H or OH,
• RVII, RVIII, RIX, RX, RXI and RXII independently of one another represent a C1-C24-alkyl radical, a C6-C24-aryl radical or H,
• the sum of x and y represents an integer in the range from 2 to 200 and w and z each independently of one another can be an integer between 0 and 100,
• with the proviso that always only one radical R′ is present per siloxane molecule.