Tire containing silicate microflakes having enhanced traction characteristics

Abstract

This invention discloses a tire having enhanced wet traction and ice traction characteristics. These tires are comprised of a generally toroidal-shaped carcass with an outer circumferential tread, two spaced beads, at least one ply extending from bead to bead and sidewalls extending radially from and connecting said tread to said beads, wherein said tread is adapted to be ground-contacting, wherein the tread includes at least one circumferential groove which separates circumferential ribs, each circumferential groove having two sides and a base therebetween, and wherein the sides of each circumferential groove are comprised of a rubbery composition that includes silicate microflakes which are substantially aligned in an orientation which is parallel with the sides of the grooves.

1 . A tire which is comprised of a generally toroidal-shaped carcass with an outer circumferential tread, two spaced beads, at least one ply extending from bead to bead and sidewalls extending radially from and connecting said tread to said beads, wherein said tread is adapted to be ground-contacting, wherein the tread includes at least one circumferential groove which separates circumferential ribs, each circumferential groove having two sides and a base therebetween, and wherein the sides of each circumferential groove are comprised of a rubbery composition that includes silicate microflakes which are substantially aligned in an orientation which is parallel with the sides of the grooves. 
     
     
         2 . The tire as specified in  claim 1  wherein the tire is a pneumatic tire. 
     
     
         3 . The tire as specified in  claim 1  wherein the tire is a non-pneumatic tire. 
     
     
         4 . The tire as specified in  claim 1  further including a carcass ply radially inward of the tread. 
     
     
         5 . The tire as specified in  claim 1  wherein the microflakes have a thickness between about 0.02 microns and 40 microns and a diameter between about 2 microns to 250 microns. 
     
     
         6 . The tire as specified in  claim 1  wherein the microflakes have a thickness between about 0.2 microns and 30 microns and a diameter between about 6 microns to 100 microns. 
     
     
         7 . The tire as specified in  claim 1  wherein the microflakes have a thickness between about 0.4 microns and 20 microns and a diameter between about 10 microns to 60 microns. 
     
     
         8 . The tire as specified in  claim 1  wherein the microflakes are comprised of a member selected from the group consisting of glass, mica, and clay. 
     
     
         9 . The tire as specified in  claim 1  wherein the microflakes are glass microflakes. 
     
     
         10 . The tire as specified in  claim 1  wherein the rubbery composition is comprised of a brominated butyl rubber. 
     
     
         11 . The tire as specified in  claim 10  wherein the rubbery composition is further comprised of a silica reinforcing filler. 
     
     
         12 . The tire as specified in  claim 1  wherein the circumferential ribs include a base portion which is free of silicate microflakes. 
     
     
         13 . A process for manufacturing a tire comprising: (1) positioning a cover layer onto an uncured tire having a generally toroidal-shaped carcass with an outer circumferential tread portion, two spaced beads, at least one ply extending from bead to bead and sidewalls extending radially from and connecting said tread portion to said beads, wherein the cover layer is comprised of a rubber compound including at least one rubbery polymer and silicate microflakes, wherein the silicate microflakes are embedded within the cover layer and positioned in such a manner that they are aligned in the cover layer in a manner whereby they are substantially parallel with the circumferential surface of the tread portion of the uncured tire; (2) placing the tire into a curing mold to form a desired tire tread having at least one circumferential groove which separates circumferential ribs, each circumferential groove having two sides and a base therebetween, wherein the silicate microflakes positioned on the sides of the grooves are substantially aligned in an orientation which is parallel with the sides of the grooves; (3) maintaining the uncured tired in the mold at an elevated temperature for a period of time that is sufficient to cure the tire; and (4) removing the tire from the curing mold. 
     
     
         14 . A process as specified in  claim 13  wherein the cover layer is an extruded sheet of rubber. 
     
     
         15 . A process as specified in  claim 13  which further comprises mechanically removing the cover layer from the circumferentially outer most portion of the tread. 
     
     
         16 . A process as specified in  claim 15  wherein the tread includes circumferential ribs, wherein the tread is adapted to be ground-contacting, and wherein removal of the outer cover results in the base rubber becoming the ground contacting area of the ribs. 
     
     
         17 . The tire as specified in  claim 1  wherein the rubbery composition is comprised of 1 to 40 parts per weight of silicate microflakes per 100 parts by weight of rubber. 
     
     
         18 . The tire as specified in  claim 1  wherein the rubbery composition is comprised of 3 to 25 parts per weight of silicate microflakes per 100 parts by weight of rubber.