Rubber compounds for use in producing vehicle tires
The invention provides diene rubber-silica compounds comprising a diene rubber matrix having dispersed therein a silica filler, wherein said silica filler is surface-modified by attachment of a π system-containing moiety which forms a π-π interaction with the diene rubber matrix. In particular, it provides such compounds in which the diene rubber is styrene-butadiene rubber. Such compounds can be vulcanized and are suitable for producing vehicle tire components, such as tire treads.
1 . A diene rubber-silica compound comprising:
a diene rubber matrix having dispersed therein a silica filler,
the silica filler having a a π system-containing moiety attached to the surface of the silica filler, the x system-containing moiety having π-π interaction with the diene rubber matrix.
2 . The diene rubber-silica compound of claim 1 , wherein the diene rubber comprises styrene-butadiene rubber, or a blend of styrene-butadiene rubber with a butadiene rubber.
3 . The diene rubber-silica compound of claim 1 , wherein the π-π interaction is formed between the π system-containing moiety and a carbon-carbon double bond and/or phenyl ring present in the diene rubber matrix.
4 . The diene rubber-silica compound of claim 1 , wherein there is a substantial absence of any covalent interactions between the silica filler and the diene rubber matrix.
5 . The diene rubber-silica compound of claim 1 , wherein the π system-containing moiety is a compound containing π systems chosen from an aromatic or heteroaromatic ring, a tropylium cation, an allyl group, or an acrolein group, and combinations thereof.
6 . The diene rubber-silica compound of claim 5 , wherein the π system-containing moiety comprises a polyphenyl compound or a synthetic resin containing one or more aromatic rings.
7 . The diene rubber-silica compound of claim 6 , wherein said synthetic resin comprises a phenolic resin, an aromatic hydrocarbon resin, a hydrogenated aromatic hydrocarbon resin, an aliphatic/aromatic hydrocarbon resin, a hydrogenated aliphatic/aromatic hydrocarbon resin, a cycloaliphatic/aromatic hydrocarbon resin, a hydrogenated cycloaliphatic/aromatic hydrocarbon resin, a polyterpene resin, a terpene-phenol resin, a coumarone-indene resin, or a grafted version of any of such resins or any mixture thereof.
8 . The diene rubber-silica compound of claim 1 , wherein said π system-containing moiety is attached to the silica filler via a linking group which forms a bond to the silica filler and a bond to the π system-containing moiety.
9 . The diene rubber-silica compound of claim 8 , wherein the linking group is represented by:
in which
* denotes a point of attachment of the linking group to a surface of the silica filler;
** denotes the point of attachment of the linking group to the π system-containing moiety;
each R is independently selected from —OH, C 1-6 alkoxy and C 1-6 alkyl; and
Z is a C 1-12 alkylene group which may be interrupted by one or more groups selected from —O—, —SiR′ 2 — (in which each R′ is independently —OH, C 1-6 alkoxy, or C 1-6 alkyl), —PR″—, —NR″—, and —OP(O)(OR″)O— (in which R″ is H or C 1-6 alkyl).
10 . The diene rubber-silica compound of claim 8 , wherein the linking group is represented by:
in which
* denotes a point of attachment of the linking group to a surface of the silica filler;
** denotes the point of attachment of the linking group to the π system-containing moiety;
each R is independently selected from —OH, C 1-3 alkoxy and C 1-3 alkyl; and
Z is a C 1-12 alkylene group which may be interrupted by one or more groups selected from —O—, —SiR′ 2 — (in which each R′ is independently —OH, C 1-6 alkoxy or C 1-6 alkyl), —PR″—, —NR″—, and —OP(O)(OR″)O— (in which R″ is H or C 1-3 alkyl).
11 . The diene rubber-silica compound of claim 9 , wherein the linking group is represented by:
in which
* denotes a point of attachment of the linking group to a surface of the silica filler;
** denotes the point of attachment of the linking group to the π system-containing moiety;
m is an integer from 0 to 12;
a is an integer from 0 to 6; and
b is an integer from 0 to 6.
12 . The diene rubber-silica compound of claim 1 further comprising a vulcanizable diene rubber-silica compound.
13 . A vulcanized rubber compound formed by cross-linking a diene rubber-silica compound as claimed in claim 12 .
14 . A vehicle tire, comprising a vehicle tire component made from the diene rubber-silica compound of claim 1 .
15 . A diene rubber-silica compound comprising:
a diene rubber matrix having dispersed therein a silica filler;
a π system-containing moiety attached to the surface of the silica filler and having π-π interaction with the diene rubber matrix,
wherein the π system-containing moiety is a compound containing π systems chosen from an aromatic or heteroaromatic ring, a tropylium cation, an allyl group, or an acrolein group, and combinations thereof.
16 . A diene rubber-silica compound comprising:
a diene rubber matrix having dispersed therein a silica filler;
a π system-containing moiety attached to the surface of the silica filler and having π-π interaction with the diene rubber matrix,
wherein the π system-containing moiety is attached to the silica filler via a linking group which forms a bond to the silica filler and a bond to the x system-containing moiety,
wherein the linking group is represented by:
in which
* denotes a point of attachment of the linking group to a surface of the silica filler;
** denotes the point of attachment of the linking group to the π system-containing moiety;
each R is independently selected from —OH, C 1-6 alkoxy and C 1-6 alkyl; and
Z is a C 1-12 alkylene group which may be interrupted by one or more groups selected from —O—, —SiR′ 2 — (in which each R′ is independently —OH, C 1-6 alkoxy, or C 1-6 alkyl), —PR″—, —NR″—, and —OP(O)(OR″)O— (in which R″ is H or C 1-6 alkyl).