Elastomeric composition exhibiting good dispersion of the filler in the elastomeric matrix

Patent metadata

Field	Value
Publication number	US-9611380-B2
Application number	US-201113994850-A
Country	US
Kind code	B2
Filing date	Dec 9, 2011
Priority date	Dec 17, 2010
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

The invention relates to a rubber composition based on at least one diene elastomer, a reinforcing filler comprising at least carbon black and an inorganic filler with an inorganic filler content of less than or equal to 50 parts by weight per hundred parts of elastomer, characterized in that the composition is obtained from a first masterbatch comprising at least one first diene elastomer and carbon black, and having a dispersion of the carbon black in the elastomeric matrix that has a Z value of greater than or equal to 90, added to which is the inorganic filler and at least one second elastomer, identical to or different from the first elastomer, and also to the process for preparing such a composition.

First claim

The invention claimed is:

1. A process for obtaining a composition based on at least one diene elastomer, a reinforcing filler comprising at least carbon black and an inorganic filler with an inorganic filler content of less than or equal to 50 parts by weight per hundred parts of elastomer, which comprises the following steps:
preparing a first masterbatch comprising the diene elastomer and the carbon black, this first masterbatch having a dispersion of the reinforcing filler in the elastomeric matrix that has a Z value greater than or equal to 90,
the step of preparing the first masterbatch including forming a coagulated mixture of the diene elastomer and the carbon black, and drying the coagulated mixture in order to recover the first masterbatch,
incorporating the inorganic filler, the second elastomer and the other constituents of the composition, with the exception of the crosslinking system, into the dried first masterbatch in a mixer, everything being kneaded thermomechanically until a maximum temperature of between 130° C. and 200° C. is reached,
cooling the combined mixture to a temperature below 100° C.,
subsequently incorporating: the crosslinking system, kneading everything up to a maximum temperature below 120° C.

2. The process according to claim 1 , wherein the inorganic filler and the second elastomer are introduced to the first masterbatch simultaneously.

3. The process according to claim 2 , wherein the inorganic filler and the second elastomer are introduced in the form of a pre-prepared second masterbatch.

4. The process according to claim 1 , wherein the inorganic filler and the second elastomer are introduced separately; the inorganic filler being introduced before or after the second elastomer.

5. The process according to claim 2 , wherein the introduction of the inorganic filler and/or of the second elastomer is offset in time by a few tens of seconds to a few minutes relative to the introduction of the first masterbatch into the mixer.

6. 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.

7. A process for obtaining a composition based on at least one diene elastomer, a reinforcing filler comprising at least carbon black and an inorganic filler with an inorganic filler content of less than or equal to 50 parts by weight per hundred parts of elastomer, which comprises the following steps:
preparing a first masterbatch comprising the diene elastomer and the carbon black, this first masterbatch having a dispersion of the reinforcing filler in the elastomeric matrix that has a Z value greater than or equal to 90,
incorporating the inorganic filler, the second elastomer and the other constituents of the composition, with the exception of the crosslinking system, into the first masterbatch in a mixer, everything being kneaded thermomechanically until a maximum temperature of between 130° C. and 200° C. is reached,
cooling the combined mixture to a temperature below 100° C.,
subsequently incorporating: the crosslinking system, kneading everything up to a maximum temperature below 120° C.,
wherein the first masterbatch is produced according to the following successive steps: feeding a continuous flow of a diene elastomer latex to a mixing zone of a coagulation reactor defining an elongate coagulation zone extending between the mixing zone and an outlet orifice, feeding a continuous flow of a fluid comprising a filler comprising carbon black under pressure to the mixing zone of a coagulation reactor to form a coagulated mixture, drying the coagulated mixture in order to recover the first masterbatch.

8. The process according to claim 1 , wherein the weight fraction of the first diene elastomer in the elastomeric matrix is greater than or equal to 50%.

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

10. The process according to claim 9 , wherein the first diene elastomer is a natural rubber.

11. The process according to claim 1 , wherein the second elastomer is a diene elastomer.

12. The process according to claim 11 , wherein the second elastomer is selected from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers and blends of these elastomers.

13. The process according to claim 11 , wherein the second diene elastomer is identical to the first diene elastomer.

14. The process according to claim 11 , wherein the second diene elastomer is a polybutadiene.

15. The process according to claim 11 , wherein the second diene elastomer is a butadiene/styrene copolymer.

16. The process according to claim 1 , wherein the second elastomer is selected from non-diene elastomers.

17. The process according to claim 1 , the inorganic filler is a silica, or a silica-covered carbon black.

18. The process according to claim 1 , wherein the content of carbon black is between 30 and 80 phr, and the content of inorganic filler is between 5 and 50 phr.

19. A process for preparing a masterbatch which comprises at least one diene elastomer, a reinforcing filler comprising at least carbon black and an inorganic filler with an inorganic filler content of less than or equal to 50 parts by weight per hundred parts of elastomer, comprising adding to a first diene elastomer and carbon black masterbatch produced according to the following steps:
feeding a continuous flow of a diene elastomer latex to a mixing zone of a coagulation reactor defining an elongate coagulation zone extending between the mixing zone and an outlet,
feeding a continuous flow of a fluid comprising a filler comprising carbon black under pressure to the mixing zone of a coagulation reactor to form a coagulated mixture,
drying the coagulated mixture in order to recover the first masterbatch, the inorganic filler and at least one second elastomer, identical to or different from the first elastomer, by thermomechanical kneading.

20. The process according to claim 19 , wherein the inorganic filler and the second elastomer are introduced simultaneously.

21. The process according to claim 19 , wherein the inorganic filler and the second elastomer are introduced in the form of a pre-prepared second masterbatch.

22. The process according to claim 19 , wherein the inorganic filler and the second elastomer are introduced separately; the inorganic filler being introduced before or after the second elastomer.

23. The process according to claim 19 , wherein the introduction of the inorganic filler and/or of the second elastomer is offset in time by a few tens of seconds to a few minutes relative to the introduction of the first masterbatch into the mixer.

24. The process according to claim 8 , wherein the weight fraction is greater than or equal to 60%.

25. The process according to claim 17 , wherein the silica is a precipitated silica.

26. The process according to claim 18 , wherein the content of carbon black is between 40 and 70 phr and the content of inorganic filler is between 10 and 30 phr.

Assignees

• Thomasson Damien
• Sevignon Marc
• Michelin Rech Tech
• Michelin & Cie

Inventors

• Thomasson Damien
• Sevignon Marc

Classifications

• C08K3/36

  Silica · CPC title

• C08J3/226

  using a polymer as a carrier · CPC title

• C08J2409/00

  Characterised by the use of homopolymers or copolymers of conjugated diene hydrocarbons · CPC title

• C08L21/00

  Compositions of unspecified rubbers · CPC title

• C08L7/00 Primary

  Compositions of natural rubber · CPC title