Robust sealed electric terminal assembly
A wire terminal assembly is disclosed in which a conductive terminal is connected to a conductive cable core along a conductive connection interface. A coating is disposed over the conductive connection interface that is the product of a free radical polymerization reaction of a coating composition applied over the conductive connection interface, the coating composition including: (1) an oligomer comprising at least two active unsaturated bonds, (2) a monomer comprising an unsaturated bond, and (3) a compound comprising a plurality of thiol groups.
1. A wire terminal assembly, comprising:
a conductive cable core;
a conductive terminal connected to the conductive cable core along a conductive connection interface; and
a coating over the conductive connection interface derived from a free radical polymerization reaction of a coating composition applied over the conductive connection interface, said coating composition comprising polymerizable compounds:
(1) an oligomer comprising at least two active unsaturated bonds,
(2) a monomer comprising an unsaturated bond, and
(3) a compound comprising a plurality of thiol groups.
2. The assembly of claim 1 , wherein the oligomer is a reaction product of a reaction mixture comprising a polyisocyanate, a polyol, and a hydroxy-functional acrylate.
3. The assembly of claim 2 , wherein the oligomer includes aliphatic groups derived from aliphatic polyols or aliphatic polyisocyanates.
4. The assembly of claim 2 , wherein the polyol includes a hydroxy-terminated polyester.
5. The assembly of claim 1 , wherein the monomer comprises a (meth)acrylate group.
6. The assembly of claim 1 , wherein the compound comprising a plurality of thiol groups has 2 to 6 thiol groups.
7. The assembly of claim 1 , wherein the compound comprising a plurality of thiol groups has the formula:
8. The assembly of claim 1 , wherein the coating composition comprises at least 1 parts per hundred by weight of the compound comprising a plurality of thiol groups, based on the total weight of polymerizable compounds.
9. The assembly of claim 1 , wherein the coating composition comprises at least 3 parts per hundred by weight of the compound comprising a plurality of thiol groups, based on the total weight of polymerizable compounds.
10. The assembly of claim 1 , wherein the coating composition comprises at least 8 parts per hundred by weight of the compound comprising a plurality of thiol groups, based on the total weight of polymerizable compounds.
11. The assembly of claim 1 , wherein the coating composition comprises at least 9 parts per hundred by weight of the compound comprising a plurality of thiol groups, based on the total weight of polymerizable compounds.
12. The assembly of claim 1 , wherein the coating composition further comprises a UV-activated free radical initiator.
13. The assembly of claim 12 , wherein the UV-activated free radical initiator comprises a xanthone, a quinone, a hydroxyalkylphenone, a benzophenone, an aminoalkylphenone, an acetophenone derivative, a benzoin derivative, a benzylketal, a 1,2-diketone, an O-acyl oximoketone, an acylphosphonate, a thiobenzoic S-ester, or a triazine, or a mixture comprising any combination of the foregoing.
14. The assembly of claim 12 , wherein the coating composition comprises at least 6 parts per hundred by weight of the UV-activated free radical initiator, based on the total weight of polymerizable compounds.
15. The assembly of claim 1 , wherein the conductive cable core and the conductive terminal comprise metals with different electrode potentials.
16. The assembly of claim 1 , wherein the coating has a cured thickness of 50 μm to 5 mm.
17. A method of making a wire terminal assembly, comprising
connecting a conductive terminal to a conductive cable core along a conductive connection interface; and
depositing and curing a coating composition over the conductive connection interface comprising:
(1) an oligomer comprising at least two active unsaturated bonds,
(2) an acrylic monomer, and
(3) a compound comprising a plurality of thiol groups.
18. The method of claim 17 , wherein the curing is carried out by exposing the coating composition to ultraviolet light.
19. The method of claim 17 , further comprising subjecting the coating composition to damage to create a discontinuity in the coating composition.
20. The method of claim 19 , further comprising spontaneous healing of the coating composition to remove the discontinuity.