Research On The Coating And Drying Technology Of Bamboo Board Based On Waterborne Coatings

Waterborne wood paint film is crystal clear,excellent performance,non-toxic and odorless,and is a good environmental protection coating.At present,domestic and foreign scholars have conducted a large amount of research on the modification,synthesis,coating,and drying process of water-based environmentally friendly paints,but at this stage,the research on the factors affecting the drying,film formation,and film quality of water-based environmentally friendly paints is not systematic.This thesis takes waterborne acrylic modified coatings as the research object to finish bamboo furniture panels,systematically studies the effects of paint types,coating processes,and drying processes on film drying time,film hardness,film adhesion,film abrasion resistance,and surface smoothness,and expounds the interrelationship between various influencing factors and film performance;Optimize the drying process of paint film,and establish a paint film drying model under the optimal process,providing a theoretical basis for waterborne finishing of bamboo furniture.The main research conclusions of this experiment are as follows:（1）The type of water-based acrylic acid has a significant impact on the drying rate and mechanical properties of the paint film.The experimental results show that T3（waterborne polyurethane acrylic acid）has the fastest drying rate under conditions of 50℃and 20%humidity.The pencil hardness of T1（waterborne acrylic acid）,T2（self crosslinking waterborne polyurethane modified acrylic acid）,and T3are 2B,B,and B,respectively;The adhesion of the three types of paint films is not affected,all of which are level 0;T1 has the best wear resistance,with a mass loss of 38.46 mg at 100 revolutions,followed by T2 and T3,with 42.52 mg and 61.68 mg,respectively;The surface smoothness of T2 paint film is the best,followed by T3,and T1 is the worst.The continuity and density of T2 and T3 paint films are better than T1;T3 has the largest particle size but poor dispersion,followed by T2.Overall,T3 performs better.（2）The effect of coating method on the drying rate and mechanical properties of the paint film is not significant.The experimental results show that the coating method has almost no effect on the drying time of the paint film;The size of adhesion and hardness is independent of the coating method.The adhesion of all four coating methods is level 0,and the hardness is level B;The wear resistance is influenced by the coating method,with one bottom and one side having the best wear resistance,resulting in a film mass loss of 51.24 mg;The microstructure observation shows that the flatness of one bottom and one side is the best.The drying time of the paint film increases with the increase of the coating amount;Excessive or insufficient coating amount can lead to insufficient wear resistance of the paint film,with a coating amount of 80 g/m2The optimal wear resistance is 51.24 mg;The adhesion and hardness are not affected by the amount of coating,and are both level 0 and level B.Comprehensive comparison of coating methods and 80 g/m²for one bottom and one side The coating amount is better.（3）Temperature,humidity,wind speed,etc.have a significant impact on the drying rate and mechanical properties of the paint film.The experimental results show that the temperature has a significant impact on the surface/solid drying time,and the drying rate of the primer and topcoat reaches its maximum at 50℃;The influence of wind speed and humidity on the drying rate of the paint film is relatively small,reaching its maximum at wind speed of 1 m/s and humidity of 20%,respectively;The adhesion and hardness of the paint film are not affected by environmental factors and are both Grade B and Grade 0;The temperature has the greatest impact on the wear resistance of the paint film,with the best wear resistance at 50℃.The influence of humidity and wind speed on wear resistance is not significant.By optimizing the response surface method,the optimal drying process was obtained as follows:temperature 55℃,humidity 25%,and wind speed 1 m/s;The optimal process for the wear resistance of the paint film is temperature 47℃,humidity 38%,and wind speed 1 m/s.（4）Model establishment and thermal performance analysis of the optimized process were co nducted.The drying models for the primer and topcoat are:the temperature rise stage of the p aint film,y=0.045*exp（-x/-1.76185）+0.045*exp（-x/2.15338）-0.09and y=-0.081*exp（-x/1.10984）-0.081*exp（-x/1.35647）+0.162.The equations for the drying stage after reaching the maximum temper ature are:y=0.12885*exp（-x/2.47524）+0.22987*exp（-x/2.47545）-0.00139 and y=0.68792*exp（-x/1.02716）+2906.62*exp（-x/1.28915）-2906.5921.The drying rate of the paint film shows a trend of i ncreasing first and then decreasing,reaching a maximum value at 2 minutes,and the drying rat e of the primer is greater than that of the topcoat.The D_effof the primer is 8.265μm²·s^-1,D_effof finish paint is 5.904μm²·s^-1.The thermal weight loss rate of the primer and the topcoat ar e basically the same,and both undergo thermal decomposition at 350℃.The thermal decompo sition rate of the primer is higher than that of the topcoat.The top coat has good thermal stab ility.