Pretreatment compositions bonded to metal substrates and methods of making the same
Described herein are graft copolymer pretreatment compositions that impart improved corrosion resistance, enhanced adhesion performance, lubrication, improved coating performance (e.g., enhanced wettability), and/or improved weldability and/or weld durability to metals (e.g., aluminum alloys) as compared to non-pretreated metal surfaces. Also provided herein are aluminum alloys coated with the disclosed graft copolymer pretreatment compositions and methods for applying the disclosed graft copolymer pretreatment compositions to aluminum alloys.
1 . A graft copolymer pretreatment composition, comprising:
a polymer backbone;
at least one surface binding or bonding moiety attached to the polymer backbone and configured to bind or bond the polymer backbone to a first surface of a metal product;
at least one functional moiety attached to the polymer backbone which comprises a polymer side chain that provides a lubricating function and configured to provide at least a first surface functionalization to the first surface of the metal product; and
at least one second functional moiety attached to the polymer backbone and configured to provide at least a second surface functionalization to the first surface of the metal product, wherein the at least one functional moiety and the at least one second functional moiety provide a multi-functional surface coating.
2 . The graft copolymer pretreatment composition of claim 1 , wherein the polymer backbone comprises an acrylic class chain polymer structure, a methacrylic class chain polymer structure, a vinyl class chain polymer structure, a diene class chain polymer structure, a vinylidene class chain polymer structure, or any combination thereof.
3 . The graft copolymer pretreatment composition of claim 1 , wherein the polymer backbone is poly(methyl methacrylate), poly(ethyl methacrylate), poly(ethyl acrylate), polyacrylonitrile, polyethylene, polypropylene, polystyrene, poly(vinyl chloride), poly(vinyl acetate), poly(vinyl alcohol), polybutadiene, polyisoprene, polychloroprene, or any combination thereof.
4 . The graft copolymer pretreatment composition of any claim 1 , wherein the at least one surface binding or bonding moiety comprises a phosphonate group, a carboxyl group, a catechol group, or a trialkoxysilyl group.
5 . A method of pretreating at least a portion of a metal surface, comprising:
applying the graft copolymer pretreatment composition of claim 1 to at least the portion of the metal surface.
6 . The method of claim 5 , wherein the applying the graft copolymer pretreatment composition comprises solution coating at least the portion of the metal surface.
7 . The method of claim 6 , wherein the solution coating comprises roll-coating, immersion coating, enrobing, spin-coating, or spray coating at least the portion of the metal surface.
8 . The graft copolymer pretreatment composition of claim 1 , wherein the at least one surface binding or bonding moiety attached to the polymer backbone is a phosphonate group.
9 . The graft copolymer pretreatment composition of claim 1 , wherein the at least one surface binding or bonding moiety attached to the polymer backbone is phosphoric acid.
10 . The graft copolymer pretreatment composition of claim 1 , wherein the at least one surface binding or bonding moiety attached to the polymer backbone is phosphonic acid.
11 . The graft copolymer pretreatment composition of claim 1 , wherein the polymer side chain that provides a lubricating function is polyethylene glycol.
12 . The graft copolymer pretreatment composition of claim 11 , wherein the poly(ethylene glycol) has a number average molecular weight (M n ) from 300 to 5000.
13 . The graft copolymer pretreatment composition of claim 1 , wherein the polymer side chain that provides a lubricating function is polysilicone.
14 . The graft copolymer pretreatment composition of claim 1 , wherein the polymer backbone is poly(methacrylate).
15 . The graft copolymer pretreatment composition of claim 1 , wherein the polymer backbone is poly(methyl methacrylate).
16 . The graft copolymer pretreatment composition of claim 1 , wherein the metal product comprises an aluminum alloy.
17 . The graft copolymer pretreatment composition of claim 1 , wherein the at least one second functional moiety comprises an adhesion promoter, a polymer side chain that provides a lubricating function, a humectant, a weld promoter, or a corrosion inhibitor.
18 . The method of claim 5 , wherein the metal surface comprises an aluminum alloy.