Organosilane coupling agent
View Patent ↗An organosilane of general formula I below: (HO) 2 R 1 Si—Z—S m —R 2 in which: R 1 , which are identical or different, each represent a monovalent hydrocarbon-based group chosen from alkyls, which are linear or branched, cycloalkyls or aryls, having from 1 to 18 carbon atoms; R 2 represents a monovalent hydrocarbon-based group chosen from alkyls, which are linear or branched, cycloalkyls or aryls, having from 1 to 30 carbon atoms; Z represents a divalent bonding group comprising from 1 to 18 carbon atoms; and m is a number greater than or equal to 2.
1. The organosilane of general formula I below:
(HO) 2 R 1 Si—Z—S m —R 2
wherein:
R 1 represents a monovalent hydrocarbon-based group chosen from alkyls, which are linear or branched, cycloalkyls or aryls, having from 1 to 18 carbon atoms;
R 2 represents a monovalent hydrocarbon-based group chosen from alkyls, which are linear or branched, cycloalkyls or aryls, having from 1 to 30 carbon atoms;
Z represents a divalent bonding group comprising from 1 to 18 carbon atoms; and
m is a number greater than or equal to 2.
2. The organosilane according to claim 1 , wherein m is equal to 2.
3. The organosilane according to claim 1 , wherein Z contains one or more heteroatoms chosen from O, S and N.
4. The organosilane according to claim 1 , wherein:
R 1 is chosen from methyl, ethyl, n-propyl and isopropyl; and
Z is chosen from C 1 -C 18 alkylenes and C 6 -C 12 arylenes.
5. The organosilane according to claim 4 , wherein Z is chosen from C 1 -C 10 alkylenes.
6. The organosilane according to claim 5 , wherein Z is chosen from C 1 -C 4 alkylenes.
7. The organosilane according to claim 4 , wherein R 1 is a methyl.
8. The organosilane according to claim 4 , wherein R 2 is chosen from alkyls having from 1 to 18 carbon atoms.
9. The organosilane according to claim 8 , wherein R 2 is an octyl.
10. The organosilane according to claim 4 , wherein m is equal to 2, R 1 is a methyl, R 2 is an octyl and Z is a propylene.
11. A process for obtaining an organosilane according to claim 1 , wherein the process comprises the steps of:
added to a diazodicarboxylate is a mercaptan of formula (II):
R 2 —SH,
in which R 2 has the same meaning as in formula (I),
in order to form a thiohydrazine,
the thiohydrazine obtained is substituted with a second mercaptan of formula (III):
(R 3 O) 2 R 1 Si—Z—SH,
in which:
R 1 and Z have the same meaning as in formula (I),
R 3 , which are identical or different, represent a monovalent hydrocarbon-based group chosen from alkyls having from 1 to 6 carbon atoms, preferably having from 1 to 3 carbon atoms,
a hydrolysis is carried out in an acid medium that makes it possible to result in the targeted organosilane of formula (I).
12. A method of making a rubber composition comprising coupling a reinforcing inorganic filler and a diene elastomer in the presence of an organosilane according to claim 1 .
13. The organosilane according to claim 1 , wherein:
R 1 is chosen from methyl and ethyl; and
Z is chosen from C 1 -C 18 alkylenes and C 6 -C 12 arylenes.