Patent ID: 7763315

Claim:
A process for preparing a coating material for metal comprising steps of: (a) obtaining a solution at 70 to 200° C. wherein a thermoplastic resin selected from the group consisting of polyethylene terephthalate, polylactic acid, polyglycolic acid, and polybutylene terephthalate is dissolved into an organic solvent; (b) obtaining a dispersion of condensation polymerized resin particles of said thermoplastic resin having an average primary particle size of 10 to 400 nm by mixing the solution with the same organic solvent as the said organic solvent, which is previously cooled down to 20 to −90° C., whereby the dispersion is cooled at a cooling speed of at least 100° C./s; (c) separating the particles from said dispersion and (d) dispersing said separated particles into a solvent.