ELASTOMERIC COMPOSITION HAVING A VERY GOOD DISPERSION OF THE FILLER IN THE ELASTOMERIC MATRIX

1 . A process for the preparation of a composition comprising at least one diene elastomer, a reinforcing filler comprising at least carbon black having a CTAB specific surface of greater than or equal to 130 m 2 /g, a plasticizing oil and also a crosslinking system, which comprises the following stages:

preparing a first masterbatch comprising the diene elastomer and the carbon black, this first masterbatch exhibiting a dispersion of the filler in the elastomeric matrix having a Z score of greater than or equal to 80,

incorporating the other constituents of the composition, with the exception of the crosslinking system, in the first masterbatch in a mixer, and kneading everything thermomechanically until a maximum temperature of between 130° C. and 200° C. is reached,

cooling the combined mixture to a temperature of less than 100° C.,

subsequently incorporating the crosslinking system,

kneading everything up to a maximum temperature of less than 120° C.

2 . The process according to claim 1 , wherein the first masterbatch is produced in the liquid phase from at least one elastomer latex and a dispersion of carbon black.

3 . The process according to claim 2 , wherein the first masterbatch is produced according to the following successive stages:

feeding a continuous stream of the diene elastomer in the form of a latex to a mixing region of a coagulation reactor defining an elongated coagulation region extending between the mixing region and an outlet orifice,

feeding a continuous stream of a fluid comprising the filler under pressure to the mixing region of a coagulation reactor in order to form a coagulated mixture,

drying the coagulum obtained above in order to recover the first masterbatch.

4 . The process according to claim 1 , wherein the plasticizing oil is selected from the group consisting of a polyolefinic oil, a paraffinic oil, a naphthenic oil, an aromatic oil, a mineral oil, or mixtures thereof.

5 . The process according to claim 4 , wherein the plasticizing oil includes a polyolefinic oil and/or a paraffinic oil.

6 . The process according to claim 4 , wherein the plasticizing oil includes a naphthenic oil, an aromatic oil, a mineral oil, and/or mixtures thereof.

7 . The process according to claim 1 , wherein the content of the plasticizing oil varies from 2 to 50 parts per hundred parts by weight of elastomer.

8 . The process according to claim 1 , wherein the diene elastomer is selected from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers, and the mixtures of these elastomers.

9 . The process according to claim 8 , wherein the at least one diene elastomer includes a natural rubber.

10 . The process according to claim 4 , wherein the plasticizing oil includes a mineral oil or a mixture of mineral oils.

11 . The process according to claim 8 , wherein the diene elastomer includes a blend of one or more natural rubber latexes with one or more synthetic rubber latexes.

12 . The process according to claim 1 , wherein the content of the carbon black varies from 20 to 80 phr.

13 . The process according to claim 1 further comprising introducing an inorganic filler, or a second elastomer, or both into the composition simultaneously with the other constituents during the kneading step.

14 . The process according to claim 13 , wherein the second elastomer is identical to or different from the at least one diene elastomer.

15 . The process according to claim 13 , wherein an inorganic filler and a second elastomer are introduced into the composition in the form of a second masterbatch.

16 . The process according to claim 15 , wherein the second masterbatch is prepared prior to its incorporation into the kneading step.

17 . The process according to claim 13 , wherein the content of the inorganic filler varies from 5 to 50 phr.

18 . The process according to claim 1 , wherein an inorganic filler and a second elastomer are introduced separately into the composition, the inorganic filler being introduced before or after the second elastomer.

19 . The process according to claim 18 , wherein the introduction of the inorganic filler and of the second elastomer is offset in time from a few tens of seconds to a few minutes with respect to the introduction of the first masterbatch into the mixer.

20 . The process according to claim 1 , wherein the content of all of the reinforcing filler varies from 20 to 200 phr.