Search

EP-3847219-B1 - MODIFIED LATENT CROSSLINKER IN POLYMERIC SYSTEMS

EP3847219B1EP 3847219 B1EP3847219 B1EP 3847219B1EP-3847219-B1

Inventors

  • SAMARANAYAKE, GAMINI S.

Dates

Publication Date
20260513
Application Date
20190905

Claims (8)

  1. A coating composition to reduce nitrogen generation upon shelf storage, the coating composition comprising: a polymer with monomer units including a ketone or carbonyl thereon; and a cross-linking compound of the formula H 2 NN(R 1 )C(O)R 2 C(O)N(R 3 )NH 2 wherein R 1 and R 3 are independently selected from a C1 to C3 alkyl hydrocarbon or an alkyl residue bearing functional groups, wherein the functional groups include carboxylic acid, hydroxyl, sulfate, sulfonate, phosphate, alkyl ether, thiol, thiol ether, amido groups and combinations thereof, and R 2 is selected from a C1 to C12 alkyl hydrocarbon; one or more multivalent cation(s) selected from copper, iron, manganese, tin, cobalt, chromium, vanadium, and mixtures thereof; wherein the coating composition comprises inorganic particles, but less than about 35 weight percent of the inorganic particles, based on the total weight of solids in the coating composition; wherein the inorganic particles include about 1 to less than about 35 weight percent titanium dioxide, based on the total weight of solids in the coating composition; wherein the polymer is an acrylic latex polymer and the monomer units include a vinyl group polymerized into a polymer backbone and the monomer units having the ketone or carbonyl thereon include an amido side group with the ketone or carbonyl at a terminal end of the side group; and wherein the coating composition includes about 45 to about 60 weight percent of the polymer and about 0.5 to about 5 weight percent of the cross-linking compound, based on the weight of solids in the coating composition.
  2. The coating composition of claim 1, wherein the coating composition includes about 0.5 to about 3 weight percent, preferably about 1.5 to about 3 weight percent, of the cross-linking compound, based on the weight of solids in the coating composition.
  3. The coating composition of claim 1 or 2, wherein R 1 and/or R 3 is an alkyl residue bearing functional groups, wherein the functional groups include carboxylic acid, hydroxyl, sulfate, sulfonate, phosphate, alkyl ether, thiol, thiol ether, amido groups and combinations thereof.
  4. The coating composition of claim 1 or 2, wherein R 2 is C4 alkyl hydrocarbon and the R 1 and R 3 groups are methyl.
  5. The coating composition of claim 1, 2, 3 or 4, wherein the polymer includes one or more of acrylic acid, acrylate, vinyl acetate, styrene, alkyd, or combinations thereof monomer units.
  6. The coating composition of claim 1, 2, 3 or 4, wherein the polymer is selected from the group of poly-acrylate, poly-vinyl acetate-acrylate, polystyrene acrylate, or alkyd-acrylic hybrid polymers and wherein monomer units include a vinyl group polymerized into a polymer backbone and wherein at least one monomer unit has a side group extending from the vinyl group and having the ketone or carbonyl therein.
  7. The coating composition of any one of claims 1 to 6, wherein the monomer units with the ketone or carbonyl thereon include diacetone acrylamide, diacetone methacrylamide, and combinations thereof.
  8. The coating composition of any one of claims 1 to 7, wherein the coating composition includes about 1 to about 500 ppm of the one or more multivalent cations(s).

Description

FIELD This application generally relates to self-crosslinking polymeric systems and compositions thereof and, more particularly, self-crosslinking polymer compositions having reduced levels of off-gassing. BACKGROUND Ambient temperature, self-crosslinking coating compositions often utilize a carbonyl- or ketone-hydrazide cross-linking reaction to achieve characteristics similar to conventional two-component crosslinking systems. After applying the coating to a substrate, the solvents and the buffering components evaporate to increase the acidity of the system, which initiates the cross-linking reaction between a carbonyl or ketone group often present on a polymer and a hydrazide group often present on a separate cross-linking agent to form a crosslinked coating or film. In some cases, however, there is a shortcoming when using prior hydrazide cross-linking technology because high levels of outgassing can occur before the cross-linking reaction is initiated. This outgassing is detrimental not only to the container used to the hold the compositions, but also negatively affects the properties of the resultant coating. In some instances, the outgassing can be sufficiently excessive so that the lid of a conventional paint can or container can pop off or plastic containers develop unsightly bulges. Neither of which are acceptable to consumers. Even if the outgassing can be contained within a sturdier container or potentially vented out of the containers, the composition remaining after significant outgassing tends to have inferior performance as evidenced by lack of durability when applied as a coating. EP 3 056 535 A1 discloses a coating composition comprising a polymer and a crosslinking agent comprising two or more alkylhydrazide groups. SUMMARY In one approach, a coating composition to reduce nitrogen generation upon shelf storage is provided, the coating composition comprising: a polymer with monomer units including a ketone or carbonyl thereon; anda cross-linking compound of the formula         H2NN(R1)C(O)R2C(O)N(R3)NH2 wherein R1 and R3 are independently selected from a C1 to C3 alkyl hydrocarbon or an alkyl residue bearing functional groups, wherein the functional groups include carboxylic acid, hydroxyl, sulfate, sulfonate, phosphate, alkyl ether, thiol, thiol ether, amido groups and combinations thereof, and R2 is selected from a C1 to C12 alkyl hydrocarbon; one or more multivalent cation(s) selected from copper, iron, manganese, tin, cobalt, chromium, vanadium, and mixtures thereof,wherein the coating composition comprises inorganic particles, but less than about 35 weight percent of the inorganic particles, based on the total weight of solids in the coating composition;wherein the inorganic particles include about 1 to about 35 weight percent titanium dioxide, based on the total weight of solids in the coating composition;wherein the polymer is an acrylic latex polymer and the monomer units include a vinyl group polymerized into a polymer backbone and the monomer units having the ketone or carbonyl thereon include an amido side group with the ketone or carbonyl at a terminal end of the side group; andwherein the coating composition includes about 45 to about 60 weight percent of the polymer and about 0.5 to about 5 weight percent of the cross-linking compound, based on the weight of solids in the coating composition. In other approaches, the coating composition of the previous paragraph may be combined with one or more optional features, which may be selected from the following individually or in any combination: wherein R1 and/or R3 is an alkyl residue bearing functional groups and the functional groups include carboxylic acid, hydroxyl, sulfate, sulfonate, phosphate, alkyl ether, thiol, thiol ether, amido groups and combinations thereof; and/or wherein the polymer includes one or more of acrylic acid, acrylate, vinyl acetate, styrene, alkyd, or combinations thereof monomer units; and/or wherein the polymer is selected from the group of poly-acrylate, poly-vinyl acetate-acrylate, polystyrene acrylate, or alkyd-acrylic hybrid polymers and wherein monomer units include a vinyl group polymerized into a polymer backbone and wherein at least one monomer unit has a side group extending from the vinyl group and having the ketone or carbonyl therein; and/or wherein the coating composition includes about 1.5 to about 3 weight percent of the cross-linking compound; and/or wherein the coating composition includes about 1 to about 500 ppm of the one or more multivalent cations(s); and/or wherein the cross-linking compound includes an alkyl modified hexanedihydrazide wherein the R1 and R3 group are methyl; and/or wherein the monomer units with the ketone or carbonyl thereon include diacetone acrylamide, diacetone methacrylamide, and combinations thereof. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a graph of nitrogen outgassing by cross-linker compound type. DETAILED DESCRIPTION A self-crosslinking coating compos