High barrier function to moisture, oxygen and odor of novel poly(vinylalcohol-acrylic acid-methylmethacrylate) (POVACOAT(R)) as a coating film

摘要

Purpose: POVACOAT is a newly developed aqueous polymer which is poly (vinyl alcohol) derivative grafted with acrylic acid and methyl methacrylate. POVACOAT is applied to coating film, granulation binder and solid dispersion carrier etc. This study focused on the improvement of moisture permeability of POVACOAT under higher relative humidity conditions by adding a pharmaceutical pigment. Methods: In order to evaluate the moisture permeability, the aluminum casing with the isolated film which was attached on the opening part (40 mm × 40 mm) was used. The aluminum casing was heat-sealed, after 3.0 g of calcium chlorides was put into the inside as a moisture absorption agent. The increase in weight per 24 hours of the calcium chloride under various relative humidity was measured, and the moisture permeability coefficient was calculated. Results: The moisture permeability coefficients of POVACOAT film showed a typical sigmoid change as relative humidity increased. It was found that the permeability coefficients under higher relative humidity were excellently modified to be in a level of 1/6 against simple POVACOAT film by adding talc.