Multifilament aramid yarn with high fatigue resistance
A method for obtaining a cord with high fatigue resistance comprised of a multifilament aramid yarn includes the steps of: a) spinning a solution of an aromatic polyamide into a coagulation bath; b) optionally neutralizing and washing the resulting multifilament yarn; c) treating the yarn on-line with a curable epoxy compound, optionally together with or followed by treating the yarn with at least one alkaline curing agent; d) obtaining the yarn having a free epoxide content of not more than 10 mmoles/kg; e) converting the yarn to a cord; g) treating the cord with a coating which is adhesive to rubber and rubber-like materials and different from the curable epoxy compound, and subjecting the cord to a further process f) comprising the step of treating the cord with a curable epoxy compound between steps e) and g).
1 . A method for obtaining a cord with high fatigue resistance, comprised of a multifilament aramid yarn, comprising:
a) spinning a solution of an aromatic polyamide into a coagulation bath;
b) optionally neutralizing and washing the resulting multifilament aramid yarn;
c) treating the multifilament aramid Yarn on-line with a curable epoxy compound, optionally together with or followed by treating the yarn with at least one alkaline curing agent;
d) obtaining from the treated multifilament aramid yarn a yarn having a free epoxide content of not more than 10 mmoles/kg;
e) converting the yarn to a cord;
g) treating the cord with a coating material that is adhesive to rubber and rubber-like materials and that is different from the curable epoxy compound,
wherein the cord is subjected to a further process f) comprising the step of treating the cord with a curable epoxy compound between steps e) and g).
2 . The method according to claim 1 wherein the curable epoxy compound comprises di- and/or triglycidyl ether of glycerol or the polyglycidyl ether of polyglycerol.
3 . The method according to claim 1 wherein the coating material that is adhesive to rubber and rubber-like materials and that is different from the curable epoxy compound, is a recorcinol-formaldehyde-latex (RFL).
4 . The cord comprised of multifilament aramid yarn obtainable by the method of claim 1 .
5 . A fiber reinforced object comprising the cord comprised of multifilament aramid yarn of claim 4 .
6 . The fiber reinforced object of claim 51 wherein the fiber reinforced object is a tire.
7 . The method according to claim 1 wherein the method further comprises incorporating the cord into a tire carcass.
8 . The method according to claim 1 wherein the treating of the multifilament aramid yarn on-line with a curable epoxy compound in step c) is conducted on a wet multifilament aramid yarn.
9 . The method according to claim 8 wherein the yarn having a free epoxide content of not more than 10 mmoles/kg is obtained in step d) after a drying and/or curing treatment.
10 . The method according to claim 1 wherein the treating of the multifilament aramid yarn on-line with a curable epoxy compound in step c) is conducted on a dry multifilament aramid yarn.
11 . The method according to claim 10 wherein the yarn having a free epoxide content of not more than 10 mmoles/kg is obtained in step d) after a curing treatment.