Anti-aging agents for rubber vulcanizates based on organic compounds containing conjugated azadienes
View Patent ↗The present invention relates to anti-aging agents based on organic compounds containing conjugated azadiene groups, which are capable of providing rubber vulcanizates with long-term protection against thermal aging, fatigue and aging as a result of the effects of oxygen. The anti-aging agents according to the present invention are further characterized in that they are hardly ever extracted from the vulcanizates by water, oils and/or gasolines or hydraulic fluids.
1. A method for reducing the aging characteristics of a rubber vulcanizate comprising admixing an anti-aging agent having the formula (I)
wherein
R 1 represents hydrogen, straight-chain or branched C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy-, C 1 -C 12 -alkylthio-, C 1 -C 12 -alkylamino, di-(C 1 -C 12 -alkyl)-amino-, C 6 -C 14 -aryl-, C 6 -C 14 -aryloxy-, C 6 -C 14 -arylthio-, C 6 -C 14 -arylamino, C 2 -C 12 -heteroaryl-, C 2 -C 12 -heteroaryloxy-, C 2 -C 12 -heteroarylthio-, C 2 -C 12 -heteroarylamino,
R 2 and R 3 are the same or different and represent straight-chain or branched C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy-, C 1 -C 12 -alkylthio-, C 1 -C 12 -alkyl-amino, di-(C 1 -C 12 -alkyl)-amino-, benzyl-, 1,1-dimethylbenzyl- or phenyl-,
or together form a 5-10-link aliphatic or aromatic, mono- or polynuclear ring system, which may optionally be interrupted once or more than once by heteroatoms selected from the group consisting of N, O and S,
R 4 to R 7 are the same or different and represent hydrogen, straight-chain or branched C 1 -C 12 -alkyl-, C 5 -C 12 -cycloalkyl- or C 6 -C 14 -aryl-, mono- or polyunsaturated, olefinic or acetylenic, straight-chain or branched C 2 -C 12 -alkenyl-, C 1 -C 12 -alkinyl- or C 5 -C 8 -cycloakenyl,
or together form a 5-8-link, aliphatic ring system, which may optionally be interrupted once or more than once by heteroatoms selected from the group consisting of N, O and S,
with at least one rubber monomer and a vulcanizing agent.
2. The method according to claim 1 , wherein the anti-aging agent is prepared by reacting substituted primary aromatic amines having the formula (II)
wherein,
R 1 represents hydrogen, straight-chain or branched C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy-, C 1 -C 12 -alkylthio-, C 1 -C 12 -alkylamino, di-(C 1 -C 12 -alkyl)-amino-, C 6 -C 14 -aryl-, C 6 -C 14 -aryloxy-, C 6 -C 14 -arylthio-, C 6 -C 14 -arylamino, C 2 -C 12 -heteroaryl-, C 2 -C 12 -heteroaryloxy-, C 2 -C 12 -heteroarylthio- and C 2 -C 12 -heteroarylamino,
R 2 and R 3 are the same or different and represent straight-chain or branched C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy-, C 1 -C 12 -alkylthio-, C 1 -C 12 -alkyl-amino, di-(C 1 -C 12 -alkyl)-amino-, benzyl-, 1,1-dimethylbenzyl-, phenyl-,
or together form a 5-10-link aliphatic or aromatic, mono- or polynuclear ring system, which may optionally be interrupted once or more than once by heteroatoms selected from the group consisting of N, O and S, with optionally substituted conjugated 1,3-enones and/or 1,3-enals having the formula (III)
wherein, R 4 to R 7 are the same or different and represent of hydrogen, straight-chain or branched C 1 -C 12 -alkyl-, C 5 -C 12 -cycloalkyl or C 6 -C 14 -aryl-, mono- or polyunsaturated, olefinic or acetylenic, straight-chain or branched C 2 -C 12 -alkenyl-, C 2 -C 12 -alkinyl- or C 5 -C 8 -cycloakenyl,
or together form a 5-8-link, aliphatic ring system, which may optionally be interrupted once or more than once by heteroatoms selected from the group consisting of N, O and S,
and wherein R 8 represents oxygen, sulfur and NR 4 group
and/or their synthetic equivalents having the formula (IV)
wherein,
R 9 and R 10 are the same or different and represent hydroxy, chloro, bromo, straight-chain or branched C 1 -C 12 -alkoxy, C 1 -C 12 -alkylthio, C 1 -C 12 -alkylamino or together form a C 2 -C 12 -alkanedioxy- or C 2 -C 12 -alkanediamino group.
3. The method according to claim 1 further comprising admixing least one additional anti-aging agent, wherein the mix ratio of anti-aging agents according to claim 1 to at least one additional anti-aging agent is 10:1 to 1:10.
4. A rubber mixture comprising at least one rubber monomer, at least one anti-aging agent and a vulcanizing agent, the anti-aging agent having the formula (I)
wherein
R 1 represents hydrogen, straight-chain or branched C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy-, C 1 -C 12 -alkylthio-, C 1 -C 12 -alkylamino, di-(C 1 -C 12 -alkyl)-amino-, C 6 -C 14 -aryl-, C 6 -C 14 -aryloxy-, C 6 -C 14 -arylthio-, C 6 -C 14 -arylamino, C 2 -C 12 -heteroaryl-, C 2 -C 12 -heteroaryloxy-, C 2 -C 12 -heteroarylthio-, C 2 -C 12 -heteroarylamino,
R 2 and R 3 are the same or different and represent straight-chain or branched C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy-, C 1 -C 12 -alkylthio-, C 1 -C 12 -alkyl-amino, di-(C 1 -C 12 -alkyl)-amino-, benzyl-, 1,1-dimethylbenzyl- or phenyl-,
or together form a 5-10-link aliphatic or aromatic, mono- or polynuclear ring system, which may optionally be interrupted once or more than once by heteroatoms selected from the group consisting of N, O and S,
R 4 to R 7 are the same or different and represent hydrogen, straight-chain or branched C 1 -C 12 -alkyl-, C 5 -C 12 -cycloalkyl- or C 6 -C 14 -aryl-, mono- or polyunsaturated, olefinic or acetylenic, straight-chain or branched C 2 -C 12 -alkenyl-, C 2 -C 12 -alkinyl- or C 5 -C 8 -cycloakenyl,
or together form a 5-8-link, aliphatic ring system, which may optionally be interrupted once or more than once by heteroatoms selected from the group consisting of N, O and S.
5. A process for preparing the rubber mixture according to claim 4 , comprising mixing the at least one or more rubber monomer with the anti-aging agent and the vulcanizing agent.
6. The process according to claim 1 , wherein the anti-aging agent is (a) 1-N-(4′-N′-phenylamino-1′-phenyl)-2-methyl-1-azabuta-1,3-diene, (b) 1-N-(4′-N′-phenylamino-1′-phenyl)-2,4-dimethyl-1-azapenta-1,3-diene, (c) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azapenta-1,3-diene, (d) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azabuta-1,3-diene, (e) 1-N-(4′-N′-phenylamino-1′-phenyl)-3,5,5-trimethyl-1-azamethylenecyclohex-2-ene, (f) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azamethylenecyclohex-2-ene, (g) 1-N-(4′-N′-phenylamino-1′-phenyl)-4-phenyl-1-azabuta-1,3-diene, or (h) combination thereof.
7. The rubber mixture according to claim 4 , wherein the anti-aging agent is (a) 1-N-(4′-N′-phenylamino-1′-phenyl)-2-methyl-1-azabuta-1,3-diene, (b) 1-N-(4-N′-phenylamino-1′-phenyl)-2,4-dimethyl-1-azapenta-1,3-diene, (c) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azapenta-1,3-diene, (d) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azabuta-1,3-diene, (e) 1-N-(4′-N′-phenylamino-1′-phenyl)-3,5,5-trimethyl-1-azamethylenecyclohex-2-ene, (f) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azamethylenecyclohex-2-ene, (g) 1-N-(4′-N′-phenylamino-1′-phenyl)-4-phenyl-1-azabuta-1,3-diene, or (h) combination thereof.
8. The process according to claim 5 , wherein the anti-aging agent is (a) 1-N-(4′-N′-phenylamino-1′-phenyl)-2-methyl-1-azabuta-1,3-diene, (b) 1-N-(4′-N′-phenylamino-1′-phenyl)-2,4-dimethyl-1-azapenta-1,3-diene, (c) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azapenta-1,3-diene, (d) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azabuta-1,3-diene, (e) 1-N-(4′-N′-phenylamino-1′-phenyl)-3,5,5-trimethyl-1-azamethylenecyclohex-2-ene, (f) 1-N-(4′-N′-phenylamino-1′-phenyl)-1-azamethylenecyclohex-2-ene, (g) 1-N-(4′-N′-phenylamino-1′-phenyl)-4-phenyl-1-azabuta-1,3-diene, or (h) combination thereof.