Chikara Kawamura

A new antifouling paint based on a zinc acrylate copolymer

Abstract A series of novel acrylic copolymers, which contains zinc atom in a form of polymeric salt and can be exchanged with e.g. sodium ions in sea water, has been developed. As the ion exchange reaction proceeds, the polymers become soluble and leach out by flow of sea water. The polymers are considered to be suitable for antifouling paints, since erosion rates of antifouling paints formulated with the polymers could easily be controlled by varying the polymers’ characteristics such as molecular weight, hydrophilicity, etc., without spoiling the paints’ overall water resistance. After dynamic immersion the copper release rates, which represent efficacy of the main biocide, increased in most of the paint samples, and the copper release rates also depended upon the leaching out behaviors of the polymers.

Coating resins synthesized from recycled PET

PET bottles collected from the Japanese market have been increasing year by year. In 2000, a total of 124,873 t of PET bottles were collected for reprocessing. Reprocessed PET is called recycled PET (hereinafter called R-PET), and 68.575 t of R-PET was used as raw materials for fibers, sheets, and various other uses in 2000. Regarding R-PET as a condensation polymer composed of ethylene glycol (EG) and terephthalic acid (t-PA), we have tried to utilize it in coating resin syntheses. Polyesters for powder coatings synthesized from R-PET in place of EG and t-PA showed the same structure and characteristics as a conventional polyester synthesized from ordinary EG and t-PA monomers. An alkyd resin for ambient temperature curing coatings was synthesized from R-PET as a substituent for EG and phthalic anhydride (PA). After modifying its monomer composition, it finally showed the same characteristics as the original resin. The use of R-PET in alkyd and polyester resin syntheses provides a beneficial means for mass consumption of R-PET.