Internal stresses in polymer coating

In this work a theory of intemal stresses in polymer coatings of lacquer for wood has been discussed, a cantilever method analyzed and a device made for quantitative determination of internal stresses in polymer coatings by the cantilever method. Also, extensive examinations of internal stresses in some acid-hardening varnishes have been carried out. The examinations of different influential factors on internal stresses proved on the one hand the functionality and practicality of the cantilever method and on the other hand made it possible to have in insight into development and relaxation of internal stresses in AH lacquer coatings for wood with regard to their structure and the method of application. It has been shown that a thinner plastified AH lacquer in proportion of aminoplasts and alkyds 1:0,8 which coatings are hard but aIso fragile and inclined to split, in a certain conditions of application develop relatively low internal stresses, just like those normaly plastified, in proportion of aminoplasts and alkyds 1:1,2 which coatings have remarkably lower hardness.