Because of the green environmental protection and high efficiency of radiation curing coating, the coating machine has been widely used in the world, and its application field is more and more widely. UV coating with excellent surface finish, it is suitable for use as a primer in the field of vacuum coating technology, in the plastic substrate can be a very bright metal appearance. With the development of automo
bile industry, many metal alternative process has been applied, at present in the automobile headlight reflection cover application areas, have been fully adopted in PC, BMC, plastic surface by vacuum aluminum plating film to improve reflection effect, for this field of UV curing coatings with good levelling property, high temperature resistance (for PC substrate requirements more than 120 DEG C, BMC substrates up to 180 DEG C).
Preparation and influence factors of UV primer for vacuum coating
This paper studies and discusses the principles of some formula of UV primer applied on the PC based automotive lamp reflector, and analyzes the various factors that affect the performance of the primer.
1, the experimental part
1.1 raw materials
Desmolux 2265 (aliphatic urethane acrylate oligomer, Bayer), CN965 (aliphatic urethane acrylate oligomer, Sartomer company) epoxy acrylate (homemade), urethane acrylate (self-made) and trihydroxy methyl propane triacrylate (TMPTA), butyl acrylate (BA) and hexanediol diacrylate (HDDA), biuret tripropylene glycol diacrylate (TPGDA), RUNTECURE1103, RUNTECURE1107 (a photo initiator, Changzhou Huasheng Titanium Co., Ltd.), Irgacure184, methyl isobutyl ketone, toluene, isopropanol and butyl acetate.
1.2 experimental instruments
UV-102 type light curing machine (Ou Shi man science and Technology Development Co., Ltd.), UV-INTEGRATOR type of UV energy meter (Germany), the type 730 Fourier infrared spectrometer (Nicolet), q-100 differential scanning calorimeter (TA instruments company), 1800 x 1950 type full automatic resistance evaporation vacuum coating machine (Foshan City Aite Mann vacuum machine factory).
Preparation of 1.3 UV coatings
The formula quantity of active oligomer, active diluent, light initiator, diluent and so on are put into the container, fully mixing evenly matched paint.
1.4 experimental methods
The UV coating spraying on PC substrate, irradiation and cured under UV curing machine, then vacuum aluminum plating, the standard method of determination of coating and substrate, coating and plating layer of the physical and mechanical properties. By using the Fu Liye infrared spectrometer, the double bond of the coating was tested by the KBr compression method. The heat flux of the coating was tested by differential scanning calorimetry (DSC), and the thermal stability of the coating was judged.
2, results and discussion
2.1 vacuum coating requirements for UV primer
In front of the vacuum coating to on the plastic substrate surface of UV coating is the main reason has the following two points: first, through the UV coating, sealing the substrate to prevent the use of vacuum coating or workpiece substrate in volatile impurities to escape and affects the coating quality. As in the headlight reflection cover applications due to the use in the process of temperature will rise to more than 100 DEG C, substrate if volatile impurities may release the hair color, discoloration, reflection of the impact effect of aluminized layer. Figure 1 (omitted) have obvious changes of heat flux DSC curves for the PC plastic, this figure shows PC substrate at a temperature of 90 DEG C or so, can be considered to have to release the material, the glass of the transition temperature (TG) of about 140 DEG C, the temperature should be lower than the temperature. Second, improve the surface roughness of the substrate, to ensure that the coating effect of the mirror surface. General plastic surface with roughness of about 0.51nn, vacuum coating thickness of not more than 0.2 m, cannot fill the irregularities of the substrate surface, not the ideal mirror effect, UV coating thickness reached 10-20 m, surface smooth degree of below 0.1 M, can and ideal coating effect Tian Pingji defects in steel plate.
In the PC material headlight reflection cover UV coating application must have the following basic characteristics: (1) flow flat state, fullness and bright film, which can ensure vacuum coating after a complete reflection film. (2) the film has a closed effect, can be at 120 degrees to ensure that the PC substrate material does not affect the release of the coating. (3) the coating itself has a certain heat resistance, 120 degrees will not have a material decomposition of the release and the impact on the coating.
Effect of 2.2 active oligomer on the properties of UV primer for vacuum coating
Fixed formula for 47% active oligomer, 20%TPGDA30% methyl isobutyl ketone and 3%1103 and study various active oligomer after UV curing coating performance differences and is feasible to be used in vacuum coating primer. The results are shown in table 1.