Rubbers having improved interaction with silica

A process for preparing a wetting agent which is capable of improving the interaction between silica and rubbery polymers which comprises the steps of:

• (1) metallating a low molecular weight rubbery polymer with lithium by reacting the low molecular weight rubbery polymer with an organo lithium compound in the presence of a member selected from the group consisting of alkali metal alkoxides, alkali metal phenoxides and chelating tertiary alkyl 1,2-ethylene diamines to produce a metallated low molecular weight rubbery polymer;
• and (2) reacting the metallated low molecular weight rubbbery polymer with a silicon containing compound to produce the wetting agent;
• wherein the silicon containing compound is selected from the group consisting of silanes and siloxanes, wherein said silanes and siloxanes contain at least two functional groups which can be the same or different and which are selected from the group consisting of alkoxy groups, tertiary amino groups, cyano groups, sulfonyl groups, epoxy groups and halogen atoms;
• and wherein the reaction between the metallated low molecular weight rubbery polymer and the silicon containing compound is conducted in the presence of a member selected from the group consisting of alkali metal alkoxides, alkali metal phenoxides and chelating tertiary alkyl 1,2-ethylene diamines.

A pneumatic tire having an outer circumferential tread wherein said tread is a sulfur-cured rubber composition which is comprised of a modified rubbery polymer and about 10 phr to about 250 phr of a silica filler;

• wherein the modified rubbery polymer was made by a process comprising the steps of (1) metallating a rubbery polymer with lithium by reacting the rubbery polymer with an organo lithium compound in the presence of a member selected from the group consisting of alkali metal alkoxides, alkali metal phenoxides and chelating tertiary alkyl 1,2-ethylene diamines to produce a metallated rubbery polymer;
• and (2) reacting the metallated rubbery polymer with a silicon containing compound to produce the modified rubbery polymer having improved silica interaction, wherein the silicon containing compound is selected from the group consisting of silanes and siloxanes, wherein said silanes and siloxanes contain at least two functional groups which can be the same or different and which are selected from the group consisting of alkoxy groups, tertiary amino groups, cyano groups, sulfonyl groups, epoxy groups and halogen atoms;
• and wherein the reaction between the metallated rubbery polymer and the silicon containing compound is conducted in the presence of a member selected from the group consisting of alkali metal alkoxides, alkali metal phenoxides and chelating tertiary alkyl 1,2-ethylene diamines.