Rubber composition comprising a diene elastomer bearing imidazole functional groups randomly distributed along the chain

Patent metadata

Field	Value
Publication number	US-2016264753-A1
Application number	US-201415031510-A
Country	US
Kind code	A1
Filing date	Oct 24, 2014
Priority date	Oct 25, 2013
Publication date	Sep 15, 2016
Grant date	—

Abstract

A rubber composition comprises a reinforcing filler and a diene elastomer bearing imidazole functional groups along the chain which are randomly distributed along the chain. Such a composition exhibits an improved compromise in certain properties such as stiffness in the cured state and hysteresis.

First claim

1 .- 41 . (canceled)

42 . A rubber composition comprising at least one diene elastomer and a reinforcing filler,
wherein the diene elastomer comprises imidazole rings of formula (I) which are randomly distributed along the chain of the diene elastomer:

wherein three of the four symbols Z, Y, R and R′, which are identical or different, each represent an atom or a group of atoms, it being possible for Z and Y to form, together with the carbon atoms to which they are attached, a ring, and the fourth symbol Z, Y, R or R′ denotes a direct or indirect attachment to the diene elastomer.

43 . The rubber composition according to claim 42 , wherein R′ denotes a direct or indirect attachment to the elastomer.

44 . The rubber composition according to claim 43 , wherein Z and Y are each a hydrogen atom.

45 . The rubber composition according to claim 43 , wherein Z and Y form, together with the carbon atoms to which they are attached, a ring.

46 . The rubber composition according to claim 42 , wherein R represents a hydrogen atom or a carbon-based group which can contain at least one heteroatom.

47 . The rubber composition according to claim 46 , wherein R is an alkyl group that contains from 1 to 12 carbon atoms.

48 . The rubber composition according to claim 42 , wherein the imidazole rings are groups grafted to the diene elastomer.

49 . The rubber composition according to claim 48 , wherein the imidazole rings are groups attached to the diene units of the diene elastomer.

50 . The rubber composition according to claim 48 , wherein the imidazole rings are grafted to the diene elastomer via groups resulting from grafting a 1,3-dipolar compound to the diene elastomer,
wherein the 1,3-dipolar compound is of formula (II):
Q-A-B  (II),

wherein Q comprises a dipole containing at least one nitrogen atom, wherein A is an atom or a group of atoms connecting Q to B, and wherein B comprises the imidazole ring of formula (I) in which the fourth symbol denoting an indirect attachment to the diene elastomer denotes a direct attachment to A.

51 . The rubber composition according to claim 50 , wherein A is an aliphatic group or an aromatic group.

52 . The rubber composition according to claim 51 , wherein A is an alkylene group or an arylene group.

53 . The rubber composition according to claim 50 , wherein the 1,3-dipolar compound is selected from the group consisting of nitrile oxides, nitrile imines and nitrones.

54 . The rubber composition according to claim 53 , wherein Q contains a —C≡N→O unit.

55 . The rubber composition according to claim 54 , wherein Q comprises a unit of formula (III):

wherein four of the five symbols R 1 to R 5 , which are identical or different, are each an atom or a group of atoms and the fifth symbol denotes a direct attachment to A, and
wherein neither of R 1 and R 5 are H.

56 . The rubber composition according to claim 55 , wherein R 1 , R 3 and R 5 are each an alkyl group of 1 to 6 carbon atoms.

57 . The rubber composition according to claim 56 , wherein the 1,3-dipolar compound is 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide or 2,4,6-triethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide.

58 . The rubber composition according to claim 53 , wherein Q contains a —C═N(O)— unit.

59 . The rubber composition according to claim 58 , wherein Q comprises a unit of formula (IV) or (V):

wherein Y 1 is an aliphatic group or an aromatic group containing from 6 to 20 carbon atoms, and
wherein Y 2 , comprising a direct attachment to A, is an aliphatic group or an aromatic group comprising, on its benzene nucleus, the direct attachment to A.

60 . The rubber composition according to claim 59 , wherein the 1,3-dipolar compound is a compound of formula (IVa), (IVb), (Va) or (Vb):

61 . The rubber composition according to claim 42 , wherein the diene elastomer is an essentially unsaturated elastomer selected from the group consisting of polybutadienes, polyisoprenes, butadiene copolymers, isoprene copolymers and mixtures thereof.

62 . The rubber composition according to claim 42 , wherein the diene elastomer comprises between 0 and 3 moles of imidazole rings per 100 moles of monomer units constituting the diene elastomer.

63 . The rubber composition according to claim 42 , wherein the reinforcing filler comprises a reinforcing inorganic filler.

64 . The rubber composition according to claim 63 , wherein the reinforcing inorganic filler is a silica.

65 . The rubber composition according to claim 63 , further comprising a silane coupling agent for bonding the reinforcing inorganic filler to the diene elastomer.

66 . The rubber composition according to claim 42 , further comprising a crosslinking system.

67 . A process for preparing a rubber composition according to claim 42 , based on at least one diene elastomer, a reinforcing filler and a crosslinking system, the process comprising the steps of:
(a) incorporating, in the diene elastomer, during a first non-productive stage, the reinforcing filler and, if appropriate, the coupling agent, by kneading thermomechanically until a maximum temperature of between 130° C. and 200° C. is reached; (b) cooling the combined mixture to a temperature of less than 100° C.; (c) subsequently incorporating the crosslinking system; and (d) kneading up to a maximum temperature of less than 120° C., wherein the diene elastomer comprises imidazole rings of formula (I) which are randomly distributed along the chain of the diene elastomer.

68 . The process according to claim 67 , wherein step (a) is preceded by a step of reacting a 1,3-dipolar compound with a diene elastomer by a bulk or solution grafting reaction,
wherein the 1,3-dipolar compound is of formula (II):
Q-A-B  (II),

wherein Q comprises a dipole containing at least one nitrogen atom, wherein A is an atom or a group of atoms connecting Q to B, and wherein B comprises the imidazole ring of formula (I) in which the fourth symbol denoting an indirect attachment to the diene elastomer denotes a direct attachment to A.

69 . A tread comprising the rubber composition according to claim 42 .

70 . A tire comprising the rubber composition according to claim 42 .

Assignees

• Michelin & Cie
• Michelin Rech Tech

Inventors

• Salit Anne-Frédérique
• Seeboth Nicolas
• Gander Sophie
• Rannoux Claire
• Thuilliez Anne-Lise

Classifications

• C08L91/06

  Waxes · CPC title

• C08L7/00

  Compositions of natural rubber · CPC title

• C08L9/06

  Copolymers with styrene · CPC title

• C08K3/04

  Carbon · CPC title

• B60C1/0016

  Compositions of the tread · CPC title