Coating composition, a process of producing a coating composition, a coated article, and a method of forming such articles
Coating compositions, processes of making coating compositions, coated articles, and methods of forming such articles. Coating compositions include a dispersion of core/shell particles. The core includes a base polymer, and the shell includes a polar polymeric stabilizing agent. One or more hydrophobic particulate fillers is embedded at least partially in the shell. Processes include: (1) selecting the base polymer; (2) selecting the stabilizing agent; (3) selecting the particulate filler(s); (4) melt-blending these, and contacting the melt-blend with water optionally with a neutralizing agent, thereby forming the coating composition including a dispersion. Coated articles include a substrate including cellulose and a dispersion on at least one surface of the substrate. Methods of making coated articles include: (1) providing a substrate including cellulose; (2) providing a coating composition including a dispersion; and (3) applying the coating composition to at least one surface of the substrate, thereby making the coated article.
1. A process for producing an aqueous coating composition comprising the steps of:
forming a melt blend of one or more base polymers, one or more polar polymeric stabilizing agents, and one or more hydrophobic particulate fillers, wherein the one or more base polymers are selected from the group consisting of ethylene/acrylic acid copolymers and ethylene/methacrylic acid copolymers;
injecting an initial amount of water and neutralizing agent into said melt blend;
melt kneading said melt blend, optionally in the presence of further neutralizing agent, under elevated pressure and heat sufficient to eliminate steam pressure build-up;
thereby forming an aqueous dispersion of particles, the particles comprising:
a core comprising said base polymer;
a shell at least partially surrounding said core, wherein said shell comprises said polar polymeric stabilizing agent; and
said one or more hydrophobic particulate fillers embedded at least partially in said shell, the at least one or more hydrophobic particulate fillers having a particle size diameter in the range of from 5 nm to 250 nm.
2. The process for producing an aqueous coating composition of claim 1 , wherein the one or more polar polymeric stabilizing agents comprises ethylene/acrylic acid copolymer.