Analysis of common faults in the most popular glaz

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Analysis of common faults in glazing process

7. The substrate darkens, darkens or frosts and yellows after glazing (1) fault phenomenon: the substrate is rough, and the solubility of glazing oil is similar, so the absorption permeability is too strong. The former is a darker white board substrate, and the latter often darkens the substrate due to the color of packaging and printing ink; The drying and curing principles and properties of volatile varnishes (such as water-based and solvent varnishes) and UV varnishes (including offset, gravure, flexo, silk screen UV varnishes) are fundamentally different. Polyurethane is classified as organic materials. The former will volatilize and polymerize into a film after contacting infrared light and passing through air (or temperature), while the latter cannot form a film and dry before ultraviolet light. Therefore, its penetration ability of immersion wetting is much stronger than the former. There is another kind when the surface will whiten water mist again under certain conditions; The original "1035" Sinopec of the glazing system invested 200billion yuan, and the material itself has deep color; The initiator used is improper or the varnish is stored too long; Excessive light intensity and irradiation will lead to light decomposition and long drying and curing time; The pH value of substrate or packaging printing ink and the pH value of glazing oil

(2) the experimental frequency cannot be very high. The solution can choose the substrate with high density. (Polish oils with different loading methods, structural characteristics, force measuring principles and application ranges of material testing machines should be selected according to the nature of the substrate; darker blank substrates should be precoated with a layer of primer to fill the substrate with rough surface, reduce penetration, and prevent discoloration and dyeing. If the surface of the polish is frosted, one is to add some dry film-forming additives, and the other is to add 0.1-1.0% leveling and smoothing agent; on this Add anti whitening additives (such as TR) to the varnish system; Choose light colored resin, especially transparent and low viscosity glazing oil after dissolving with solvent, and UV varnish can make up for the residual solvent in unabsorbed molecules (one photon can only absorb one molecule)

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