Common knowledge of coating: disadvantages in Polyurethane Construction

Core tips: polyurethane coating is widely used in furniture coating Polyurethane wood coating has good physical and mechanical properties, bright and full coating, hard and wear-resistant, good flexibility, and high decorative effect Although polyurethane has a very good decorative effect, but in the process of construction, it is easy to appear "prickly heat" coating defects The so-called "prickly heat" is a layer of compact small bubbles formed inside the paint film, which makes the film protrude one by one, and these "prickly heat" seriously affect the external quality of the film New below Application scope and advantages of roller ceramic coating Recommended introduction: the surface of ceramic rubber plate used for roller ceramic coating is cast into durable rubber plate by hundreds of independent small ceramic pieces Each ceramic piece has raised characteristics Under general conveyor belt pressure, thousands of unique cast bumps can produce positive traction, prevent slipping and extend the service life of conveyor belt roller At the same time, the bottom layer adopts high-quality rubber, which has strong elasticity and can play a good impact resistance role The scope of application of roller ceramic coating is one three six 83857180 (the same as V) 1 Roller coating in extremely harsh working environment 2 The belt joint is not suitable for fixing with iron buckle; 3 It is suitable for leather Home of coatings: polyurethane coating is widely used in furniture coating Polyurethane wood coatings have good physical and mechanical properties, bright and full coating, hard and wear-resistant, good flexibility, and high decorative effect Although polyurethane has a very good decorative effect, but in the process of construction, it is easy to appear "prickly heat" coating defects The so-called "prickly heat" is a layer of compact small bubbles formed inside the paint film, which makes the film protrude one by one, and these "prickly heat" seriously affect the external quality of the film The following new coating mesh small analysis of the causes of "prickly heat" "Prickly heat" is caused by the evaporation of wet film solvent during the drying process If the air in the substrate pores is expanded, and if the PU coating is mixed with the gas generated by the reaction of water and -NCO base, if the solvent on the coating surface evaporated rapidly, the film is not yet completely solidified, but it has formed a soft film in the gel state, resulting in the bubbles and solvents in the coating can not break through the coating The air bubbles have a certain movement ability The formation of air pressure will jack up the film After drying, the air bubbles will be enclosed in the film to form the bulging dark bubbles, which will produce "prickly heat" There are several possible causes 1、 In order to get the most profit, some coating manufacturers use curing agent and diluent with poor quality in the process of coating production Because most of these diluents use recycled solvent, there are too many low boiling point solvents, the solvent volatilization is unbalanced or the solubility is unbalanced After spraying, the surface solvent of the coating film volatilizes rapidly, resulting in too fast surface drying of the coating It often contains slow drying solvent with poor solubility, so that the bubbles inside the film and the steam of slow drying solvent can not be completely released and smoothly escape from the coating 2、 Impact during site construction In the construction process, if the dilution ratio is improper, the viscosity of the paint is too high, and the mixing time is too long, the small bubbles will be distributed in the paint liquid and suspended in the paint liquid for a long time In addition, if the coating is not standardized, the pressure of the spray gun is too large, the diameter of the spray gun is small, and the distance between the spray gun and the workpiece is too far, so that the air will be mixed in the moment when the paint mist collides with the substrate, and these air will remain in the film to form bubbles 3、 External factors of construction environment If the weather is too humid during the construction, the water vapor in the air will penetrate into the coating and react with the curing agent to generate carbon dioxide, which will generate bubbles and "prickly heat"; if the temperature is too high, the surface of the coating will cure rapidly, but the bubbles inside the coating have not been discharged in time, and finally "prickly heat" phenomenon will be formed 4、 Influence of base material Most of the common furniture is made of porous base material with poor texture and soft wood There are many wood grains and pores on the surface of these wood These grains and pores contain more air and water vapor If these substrates are not reprocessed before coating, these air and water vapor will be discharged to form "prickly heat" Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,