The main test instrument-- QHQ type coating film pencil scratch Hardness Tester
Once the adhesion between the coating and the base material, the base coat and the middle layer or the top coat in furniture finishing is less than the internal stress and external stress, the coating will peel off. Among them, the paint film adhesion between the substrate and the water-based sealing primer is the basis of the entire paint film adhesion, which needs to be large enough to ensure the entire paint film adhesion. Secondly, the most important function of the sealing primer is to seal the substrate. On the one hand, it prevents or slows down the moisture in the wood from moving outward. On the other hand, it prevents the solvent water in the water-based primer from penetrating into the wood. It is usually evaluated by water resistance. Hardness also plays an important role in the overall paint film quality. Therefore, in this paper, when studying the influence of the surface roughness of the blank on the quality of the sealer paint film, the three indicators of sealer primer adhesion, water resistance, and hardness are selected to measure. The thickness of the paint film was measured simultaneously with the measurement of adhesion.
According to the national standard of the People's Republic of CHINA, the cross-cut method for measuring the adhesion of paint film on furniture surface GB4893.4-85, the paint film adhesion of water-based sealing primer was measured. Specific operation: cut 11 parallel cuts (about 10-20mm in length, 1mm distance between cuts) on the coated sample with a blade or a scratcher, which should cut through the entire depth of the paint film; then Cut 11 same cuts, perpendicular to the former, to form 100 small squares, stick them with scotch tape or zinc oxide adhesive plaster, observe the degree of paint film damage and record the results; the results of paint film adhesion are based on cut marks The breakage rate of the paint film at the intersection is expressed, that is, the percentage of the number of broken squares of the paint film on the substrate to the total number of squares. Each roughness plate was tested 3 times.
According to GB 4983.1-85, the test method for the liquid resistance of paint film on the surface of furniture of the People's Republic of CHINA, the water resistance of the surface of wooden furniture coating substrates was determined.
According to the national standard GB/T6739-1996 of the People's Republic of CHINA, the hardness of the paint film is determined by the pencil method.
For more information, please refer to the full text of "Research on the Application of Water-based Coatings in the Finishing Process of Wooden Furniture" (Chen Xiulan)
(Northern Chao recommends that you use a scratcher to measure coating adhesion)
