Internal stresses in systems composed of layers of impregnating resin and lacquer coating used in the manufacture of artificial veneer
The polycondensation and thermal stresses in layers of plastified impregnating urea-formaldehyde resins, in coating from chemosetting water-dilutable lacquers, and in two-layer systems composed of lacquer coating and impregnating resin have been determined. Curing of resins and coatings has been carried out at temperatures in the range of 60—140°C. It has been found that in the resin layer there are appeared tensile stresses of 4—5 MPa, in the lacquer coating of 4—16 MPa and in the two-layer systems of 2—5 MPa. Conditioning at ambient conditions changes the tensile stresses into compressive stresses in the resin layer and a relaxation of stresses in lacquer coatings to the value of 2—13 MPa and in the two-layer systems to 0.3—0.6 MPa. This relaxation is due to the absorption of humidity from environment by resins and lacquer coatings.
If you are interested in full versions of articles, please contact the editorial team of firstname.lastname@example.org