Method for making a self-sealing composition

Patent metadata

Field	Value
Publication number	US-9556329-B2
Application number	US-200913055653-A
Country	US
Kind code	B2
Filing date	Jul 20, 2009
Priority date	Jul 24, 2008
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A process for manufacturing a self-sealing elastomer composition, said process comprising the following steps: a masterbatch, comprising at least one diene elastomer and more than 30 phr of a hydrocarbon resin, is firstly manufactured by compounding these various components in a mixer at a temperature or up to a temperature called the “hot compounding” temperature which is above the softening point of the hydrocarbon resin; and then at least one crosslinking system is incorporated into the masterbatch thus prepared, by compounding everything in the same mixer or in a different mixer, at a temperature or up to a temperature which is kept below 100° C., in order to obtain said self-sealing composition.

First claim

The invention claimed is:

1. A process for manufacturing a self-sealing elastomer composition, comprising the steps of:
a) a masterbatch, comprising at least one unsaturated diene elastomer and between 40 and 80 phr of a hydrocarbon resin, is firstly manufactured by compounding the at least one unsaturated diene elastomer and hydrocarbon resin in a mixer at a temperature or up to a temperature called the “hot compounding” temperature which is above the softening point of the hydrocarbon resin, wherein the at least one unsaturated diene elastomer comprises a greater than 50 phr primary unsaturated diene elastomer selected from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers, and mixtures thereof;
b) then at least one crosslinking system is incorporated into the masterbatch thus prepared, by compounding everything in the same mixer or in a different mixer, at a temperature or up to a temperature which is kept below 100° C., in order to obtain said self-sealing composition; and
c) optionally a filler is added with a content between 0 and 30 phr during step 2) or step b),
wherein during the hot compounding step a), the unsaturated diene elastomer is brought into contact with the hydrocarbon resin in the liquid state,
wherein the hydrocarbon resin is injected in the liquid state into the same mixer or a different mixer, and
wherein said hydrocarbon resin has a glass transition temperature (Tg) above 25° C., a softening point above 50° C., a number-average molecular weight (Mn) of between 400 and 2000 g/mol, and a polydispersity index (Ip) of less than 3 (where Ip=Mw/Mn, and Mw is the weight-average molecular weight).

2. The process according to claim 1 , wherein step a) for hot compounding the unsaturated diene elastomer with the hydrocarbon resin is carried out away from oxygen.

3. The process according to claim 1 , wherein the hot compounding temperature is above 70° C.

4. The process according to claim 1 , wherein the hot compounding step a) is carried out in a compounding screw extruder.

5. The process according to claim 1 , wherein the compounding temperature of step b) is kept below 80° C.

6. The process according to claim 1 , wherein the compounding temperature of step b) is kept below the softening point of the hydrocarbon resin.

7. The process according to claim 1 , wherein the compounding temperature of step b) is kept below 50° C.

8. The process according to claim 1 , wherein the compounding step b) is carried out on a two-roll open mill.

9. The process according to claim 8 , wherein the rolls of the open mill are cooled to a temperature below 40° C.

10. The process according to claim 1 , wherein an intermediate step of cooling the masterbatch is inserted between steps a) and b) so as to cool the masterbatch to a temperature below 100° C.

11. The process according to claim 10 , wherein the temperature to which the masterbatch is cooled during said intermediate cooling step is below 80° C.

12. The process according to claim 10 , wherein the temperature to which the masterbatch is cooled during said intermediate cooling step is below the softening point of the hydrocarbon resin.

13. The process according to claim 7 , wherein the filler is introduced during compounding step b).

14. The process according to claim 7 , wherein the filler content is between 0 and 20 phr.

15. The process according to claim 7 , wherein the filler is carbon black.

16. The process according to claim 15 , wherein the carbon black content is less than 5 phr.

17. The process according to claim 16 , wherein the carbon black content is between 0.5 and 2 phr.

18. The process according to claim 1 , wherein the primary unsaturated diene elastomer is selected from the group consisting of natural rubber, synthetic polyisoprenes and mixtures thereof.

19. The process according to claim 18 , wherein the primary unsaturated diene elastomer selected from the group consisting of natural rubber, synthetic polyisoprenes and mixtures thereof is the sole elastomer of the composition.

20. The process according to claim 1 , wherein the hydrocarbon resin content lies in the 45 to 75 phr range.

21. The process according to claim 1 , wherein the hydrocarbon resin is selected from the group consisting of cyclopentadiene (CPD) homopolymer or copolymer resins, dicyclopentadiene (DCPD) homopolymer or copolymer resins, terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins and mixtures thereof.

22. The process according to claim 1 , wherein the crosslinking system is a vulcanization system based on sulphur and optionally a guanidine derivative.

23. The process according to claim 22 , wherein the guanidine derivative is diphenylguanidine (DPG).

24. The process according to claim 22 , wherein the vulcanization system comprises between 0.1 and 1.5 phr of sulphur and between 0 and 1.5 phr of guanidine derivative.

25. The process according to claim 1 , wherein the masterbatch comprises a natural rubber, synthetic polyisoprenes and mixtures thereof as a sole elastomer.

Assignees

• Pialot Frederic
• Fombelle Damien
• Voge Bozena
• Merino Lopez Jose
• Michelin Rech Tech
• Michelin & Cie

Inventors

• Pialot Frederic
• Fombelle Damien
• Voge Bozena
• Merino Lopez Jose

Classifications

• C08L101/00

  Compositions of unspecified macromolecular compounds · CPC title

• C08L2666/04

  Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof · CPC title

• C08J3/226

  using a polymer as a carrier · CPC title

• C08J2407/00

  Characterised by the use of natural rubber · CPC title

• C08L9/00

  Compositions of homopolymers or copolymers of conjugated diene hydrocarbons · CPC title