Mill base composition and UV curable ink composition comprising same
A mill base composition includes a compound comprising a divinyl ester of a dicarboxylic acid, a dispersing agent, and a pigment. The divinyl ester of the carboxylic acid includes from 2 to about 8 carbon atoms. The mill base composition is subjected to milling with milling beads to produce a milled mill base composition that functions as a pigment concentrate that may be added to an ink vehicle to form an ink composition suitable for use in inkjet ink devices. The milled mill base composition is particularly suited for UV curable ink compositions. A UV curable ink composition includes the pigment concentrate, one or more UV curable monomers, and one or more UV initiators.
1. A mill base composition comprising:
a compound comprising a divinyl ester of a dicarboxylic acid wherein the dicarboxylic acid comprises from 2 to about 8 carbon atoms, wherein the divinyl ester is present in an amount of 40-60% by weight based on the total weight of the mill base composition, wherein the dicarboxylic acid is selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, cyclohexyl dicarboxylic acid, phthalic acid, terephthalic acid, and pimelic acid,
5-30% by weight of a dispersing agent based on the total weight of the mill base composition, wherein the dispersing agent further comprises an organic solvent in an amount of about 30% to about 50% by weight of the dispersing agent, and
20-40% by weight of a pigment based on the total weight of the mill base composition.
2. The mill base composition according to claim 1 wherein the dispersing agent is selected from the group consisting of polyesters, polyurethanes, and polyalkylene imines.
3. The mill base composition according to claim 1 wherein the organic solvent is selected from the group consisting of acetates, glycols, and combinations of acetates and glycols.
4. The mill base composition according to claim 1 wherein the dispersing agent further comprises a (meth)acrylic monomer in an amount of about 30% to about 50% by weight of the dispersing agent.
5. The mill base composition according to claim 4 wherein the (meth)acrylic monomer is selected from the group consisting of 2-phenoxyethyl acrylate, isophoryl acrylate, isodecyl acrylate, tridecyl acrylate, lauryl acrylate, 2-(2-ethoxy-ethoxy)ethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, propoxylated acrylate, tetrahydrofurfuryl methacrylate, 2-phenoxyethyl methacrylate, isobornyl methacrylate, and combinations of two or more thereof.