Hits:Updated:2016-08-04 14:08:41【Print】
Most real fresh metal surface has a higher surface free energy (500 ~ 5000mN / m), far higher than the surface of the organic polymer material can (less than 100mN / m). This high energy surface adhesion of the coating is very advantageous, in fact, a lot of metal in the air is easy to produce an oxide film, the surface free energy is relatively lower, affect the paint adhesion, but in any case, the vast majority of the surface of a metal oxide film still higher than the free energy of a conventional light-cured coatings, paint and therefore not a big problem for the metal substrate wetting should. However, UV coating applied to metal substrates often encountered problem is poor adhesion to the metal coating, if no special features to add additives, conventional UV coating for metal is difficult to obtain a good adhesion, which may because dense metal substrate surface, the organic coating can not penetrate absorption, the less significant the contact interface, unlike paper, plastic, wood and other substrates can be formed as penetration anchor structure. Another reason may be the most acrylic ester resin and a higher cure shrinkage monomers have a relationship, the internal stress generated by curing shrinkage of the film is largely a reaction to the metal substrate adhesion. Metal blasting, phosphate, electrochemical treatment, may help to improve coating adhesion, but after all, is only one aspect relating to adhesion problems, and these treatments exist or affect the appearance or reduce the coating efficiency and other issues. How to adjust the formula to improve the photo-curable coating adhesion on various metal substrates UV industry is more concerned about the issue. Solve coating adhesion solution is often to add an adhesion promoter in UV coating formulations, the source Accor chemical treatment agents used in metal enhance the adhesion of UV metal, from a connecting role, hinges on the substrate and UV, to achieve adhesion . Widely used in all kinds of zinc alloy, magnesium alloy, stainless steel hardware and water on the vacuum coating or plating, can assist in strengthening the bonding metal layer and UV coating, while the most commonly used solvent and has a good affinity resin, widely recognized by the market is a common type of treatment agent. Physical properties: 1. Appearance: light yellow turbid liquid 2, solid content: 25% 3, softening temperature: about 80 ℃ 4, molecular weight: 60000-90000 Construction Technology: 1, the cleaning → spraying metal coating process hardware (PVD) coating the surface of the treated water for 3-5 minutes to dry → → → IR UV paint spraying leveling (60 ± 10 ℃ × 4 ~ 6min) → UV curing (700 ± 100mj / cm2) → test, the next step. 2, the application viscosity: 8 ± 1 seconds (Iwata Cup # 2) 3, working pressure: 3-4Kg / cm2 4, coating film thickness: thickness of the coating metal treatment agent is generally controlled between 3-5μm best effect, UV paint film thickness is 10-15μm |