Amine-based primer coatings for electrophotographic printing
Electrophotographic printing techniques offer excellent image quality, but image adhesion to a desired substrate may be problematic in many instances. Primer coatings for improving image adhesion to a substrate may be formed from primer compositions comprising a fluid and an amine-functionalized copolymer dispersed in the fluid as an emulsion, in which the amine-functionalized copolymer has an amine number of about 10 to about 180 mg KOH/g copolymer. The fluid may be aqueous or organic. Suitable amine-functionalized copolymers may be formed by an emulsion polymerization reaction of one or more first ethylenically unsaturated monomers lacking an amine group and one or more second ethylenically unsaturated monomers bearing at least one amine group. The at least one amine group comprises a side chain of the amine-functionalized copolymer.
1. A primer composition comprising:
an emulsion-polymerized amine-functionalized copolymer dispersed as an emulsion in an aqueous fluid having a pH of about 7.5 to about 10 and containing a starch and an anionic surfactant, a neutral surfactant or any combination thereof, the amine-functionalized copolymer having an amine number of about 70 to about 140 mg KOH/g copolymer in the emulsion and a glass transition temperature of about 0° C. to about 50° C.;
wherein the amine-functionalized copolymer comprises a polymerized reaction product of:
one or more first ethylenically unsaturated monomers lacking an amine group; and
one or more second ethylenically unsaturated monomers bearing at least one amine group, the at least one amine group comprising a side chain of the amine-functionalized copolymer.
2. The primer composition of claim 1 , wherein a cationic surfactant is not present in the aqueous fluid.
3. The primer composition of claim 1 , further comprising:
an adhesion promoter differing from the amine-functionalized copolymer dispersed in the aqueous fluid.
4. A primer composition comprising:
an aqueous fluid having a pH of about 7.5 to about 10 and containing a starch and an anionic surfactant, a neutral surfactant, or any combination thereof; and
an amine-functionalized copolymer dispersed as an emulsion in the aqueous fluid, the amine-functionalized copolymer having an amine number of about 10 to about 180 mg KOH/g copolymer in the emulsion;
wherein the amine-functionalized copolymer comprises a polymerized reaction product of:
one or more first ethylenically unsaturated monomers lacking an amine group; and
one or more second ethylenically unsaturated monomers bearing at least one amine group, the at least one amine group comprising a side chain of the amine-functionalized copolymer.
5. The primer composition of claim 4 , further comprising:
an adhesion promoter differing from the amine-functionalized copolymer dispersed in the aqueous fluid.
6. The primer composition of claim 4 , wherein the amine-functionalized copolymer further comprises at least one monomer unit bearing a side chain carboxylic acid.
7. The primer composition of claim 4 , wherein the amine number ranges from about 70 to about 140 mg KOH/g copolymer in the emulsion.
8. The primer composition of claim 4 , wherein a cationic surfactant is not present in the aqueous fluid.
9. The primer composition of claim 4 , wherein the one or more first ethylenically unsaturated monomers comprise at least one monomer selected from the group consisting of an alkyl or cycloalkyl (meth)acrylate, n-butyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, styrene, a substituted styrene, a diene, 1,3-butadiene, isoprene, a vinyl ester, vinyl acetate, a nitrile, (meth)acrylonitrile, an olefinically unsaturated halide, vinyl chloride, vinyl bromide, hydroxyethyl (meth)acrylate, hydroxylpropyl (meth)acrylate; (meth)acrylamide, a substituted (meth)acrylamide, N-methylol (meth)acrylamide, diacetone acrylamide, allyl methacrylate, divinyl benzene, alkylene glycol di(meth)acrylates, and any combination thereof.
10. The primer composition of claim 4 , wherein the one or more second ethylenically unsaturated monomers comprise at least one monomer selected from the group consisting of 2-(dimethylamino)ethyl methacrylate, 2-(diethylamino)ethyl methacrylate, 2-(tert-butylamino)ethyl methacrylate, and any combination thereof.
11. The primer composition of claim 4 , wherein the amine-functionalized copolymer comprises a first portion of amine groups that are protonated and a second portion of amine groups that are unprotonated.
12. The primer composition of claim 4 , wherein the amine-functionalized copolymer has a glass transition temperature of about 0° C. to about 50° C.
13. A coated substrate comprising:
a base substrate; and
a primer coating disposed upon a surface of the base substrate, the primer coating being formed upon the surface of the base substrate through evaporation of a primer composition;
wherein the primer composition comprises an aqueous fluid having a pH of about 7.5 to about 10; a starch; an anionic surfactant, a neutral surfactant, or any combination thereof; and an amine-functionalized copolymer dispersed as an emulsion in the aqueous fluid and having an amine number of about 10 to about 180 mg KOH/g copolymer in the emulsion;
wherein the primer coating comprises the amine-functionalized copolymer, the starch, and the anionic surfactant, the neutral surfactant, or any combination thereof; and
wherein the amine-functionalized copolymer comprises a polymerized reaction product of:
one or more first ethylenically unsaturated monomers lacking an amine group; and
one or more second ethylenically unsaturated monomers bearing at least one amine group, the at least one amine group comprising a side chain of the amine-functionalized copolymer.
14. The coated substrate of claim 13 , wherein the base substrate comprises a polymeric substrate or a paper substrate.
15. The coated substrate of claim 13 , wherein the base substrate comprises a paper substrate.
16. The coated substrate of claim 13 , wherein the primer coating has a coating weight ranging from about 0.05 g/m 2 to about 1.5 g/m 2 .
17. The coated substrate of claim 13 , wherein the amine-functionalized copolymer has a glass transition temperature of about 0° C. to about 50° C.
18. The coated substrate of claim 13 , wherein the primer coating lacks a cationic surfactant.
19. The coated substrate of claim 13 , further comprising:
a toner deposited upon the primer coating.
20. A method comprising:
combining one or more first ethylenically unsaturated monomers lacking an amine group with one or more second ethylenically unsaturated monomers bearing at least one amine group in an aqueous fluid having a pH of about 7.5 to about 10 and containing a starch and an anionic surfactant, a neutral surfactant, or any combination thereof; and
forming an amine-functionalized copolymer in an emulsion polymerization reaction of the one or more first ethylenically unsaturated monomers and the one or more second ethylenically unsaturated monomers conducted in the aqueous fluid, thereby providing a primer composition comprising the amine-functionalized copolymer dispersed as an emulsion in the aqueous fluid;
wherein the amine-functionalized copolymer has an amine number of about 10 to about 180 mg KOH/g copolymer in the emulsion.
21. The method of claim 20 , further comprising:
disposing the primer composition upon a base substrate; and
evaporating the aqueous fluid to leave a primer coating comprising the amine-functionalized copolymer disposed upon the base substrate.
22. The primer composition of claim 1 , wherein the aqueous fluid has a pH of about 8.5 to about 10.
23. The primer composition of claim 4 , wherein the aqueous fluid has a pH of about 8.5 to about 10.
24. The method of claim 20 , wherein the aqueous fluid has a pH of about 8.5 to about 10.