Rubber reinforcing compositions

Claim 2

The process of claim 1 wherein step (a) is achieved prior to step (b).

Claim 3

The process of claim 1 wherein step (a) is achieved substantially concomitantly with step (b).

Claim 4

The process of claim 1 wherein said carbon black has a dibutylphthalate absorption factor of greater than about 70 cc./100 grams.

Claim 5

The process of claim 1 wherein said precipitated silica has a BET-N2 surface area of between about 75 and about 150 m.2/ gram.

Claim 6

The process of claim 1 wherein said mixture consists essentially of about 70 weight percent of said carbon black and about 30 weight percent of said precipitated silica.

Claim 7

The process of claim 1 wherein said carbon black/silica mixture is fluid energy milled to an apparent density of less than about 7 lbs./ft.3.

Claim 8

The process of claim 1 wherein, subsequent to step (b), the resulting fluffy carbon black/silica product is pelletized.

Claim 9

A superior rubber reinforcing composition consisting essentially of a mixture of carbon black and precipitated silica, said carbon black having an original apparent density of greater than about 10 lbs./ft.3, a BET-N2 surface area of between about 30 and about 250 m.2/g. and a dibutylphthalate absorption factor of greater than about 50 cc./100 g. and said precipitated silica having an original apparent density of greater than about 10 lbs./ft.3, and a BET-N2 surface area of between about 50 and about 250 m.2/g., and which mixture has been fluid energy milled to an apparent density of less than about 9 lbs./ft.3.

Claim 10

The composition of claim 9 wherein said carbon black has a dibutylphthalate absorption factor greater than about 70 cc./100 g. and said precipitated silica has a BET-N2 surface area of between about 75 and about 150 m.2/g.

Claim 11

A reinforced rubber composition comprising natural rubber and between about 30 and about 85 percent by weight thereof of a carbon black/precipitated silica mixture produced by fluid energy milling a mixture consisting essentially of: a. between about 10 and about 50 weight percent of a precipitated silica having a BET-N2 surface area of between about 50 and about 250 m.2/g. and an apparent density oF above about 10 lbs./ft.3; and b. between about 90 and about 50 weight percent of a carbon black having a BET-N2 surface area of between about 30 and about 150 m.2g., a dibutylphthalate oil absorption factor of greater than about 50 cc./100 g. and an apparent density of greater than about 10 lbs./ft.3 to an apparent density of less than about 9 lbs./ft.3.