Study on the film properties of lacquer modified by rosin.

Effect of adding rosin into raw lacquer on the film properties was studied.The result showed that the addition of rosin or its alcoholic solution can improved the film properties.The film properties are the best when rosin dosage is 5%.The film properties were improved significantly when 5% rosin was added into the reation product of raw lacquer and Fe3+,the drying time is shortened to 53h,film adhesion is 4-5 level,impact resistance is less than 30kg/cm,film hardness(by pencil test) is 2H.The result of IR showed that ester was obtained from the esterification of hydroxyl of the raw lacquer with the carboxyl of the rosin,which improves the film properties.