Study On The Preparation Of New Fluorescent Powder Coating And Its Weather Resistance

Fluorescent powder coating is a special coating with bright colors,which is widely used in transportation,construction,advertising and other industries.However,the main component of fluorescent paints,fluorescent pigments,has the disadvantages of poor weather resistance and poor thermal stability,which limits the application of fluorescent paints in outdoor environments.The ultraviolet resistance of fluorescent pigments can be improved by adding substances with ultraviolet resistance.Because of its high refractive index and high light activity,nano titanium dioxide has excellent ultraviolet shielding effect,which can help improve the ultraviolet resistance of fluorescent powder coatings.However,it is difficult to effectively protect the pigment by dispersing the titanium dioxide directly in the powder coating.Therefore,this experiment mainly enhances the ultraviolet resistance of fluorescent pigments by enhancing the combination of nano titanium dioxide and fluorescent pigments,and then improves the weather resistance of fluorescent powder coatings.In this experiment,the fluorescent pink pigment with poor weather resistance was used as the research object.Two methods are used to coat titanium dioxide on the surface of fluorescent pigments:（1）Direct coating of the inorganic compound:the titanium dioxide sol gel was combined with the rutile nano titanium dioxide to carry out the fluorescent pigment direct coating,and the effects of aging time and other factors on the UV resistance of fluorescent pigments and powder coatings were investigated.The experiment found that when the aging time of A Ti O₂ is 18h,the ratio of Ti O₂ and pigment is 2:8,the ratio of A Ti O₂ and R Ti O₂ is 2:1,the modified fluorescent pigment has the strongest UV resistance,and the color difference of the coating changes within 2h of UV-B irradiation time.It is only half of the original fluorescent powder coating,but the gloss and DOI of the fluorescent coating after coating are seriously reduced;（2）Organic compound bonding coating method:using organic resin as a binder,coating the rutile nano titanium dioxide on the surface of fluorescent pigments,the curing agent and resin contained in the binder are cured to form a film on the surface of the fluorescent pigment to achieve the coating of the nano-titanium dioxide on the surface of the fluorescent pigment,the influence of the quantity and type of binder resin on the UV resistance of pigments and powder coatings was also studied.The experiment found that compared with the original fluorescent powder coating,the ratio of polyester varnish to Ti O₂ is 2:1,the ratio of Ti O₂ to fluorescent pigment is 2:8,the comprehensive performance of modified fluorescent pigment is the best.The color difference of the coating changes within 2 hours of UVB ultraviolet irradiation,it is only half of the original fluorescent powder coating,and the initial color of the coating is slightly different from the original coating,and the gloss and DOI are basically unchanged.Therefore,the fluorescent powder coating coated with polyester varnish not only improves the weather resistance of the fluorescent powder coating,but also maintains the appearance performance of the fluorescent powder coating,and increases the possibility of commercial application.