Photoinitiator 819 CAS 162881-26-7

As a new type of photoinitiator, acylphosphine oxides such as photoinitiator 819 have been widely used in coatings, inks, adhesives and other industries due to their excellent properties. They have greater absorption in the UV and visible regions and are more effective at initiating cure than other photoinitiators for pigmented coating systems. Acylphosphine oxide photoinitiators show little yellowing after curing and long-term light irradiation, so they can be used in applications with strict yellowing requirements, such as: white, light-colored inks and coatings. In addition, the acylphosphine oxide has a bleaching effect on light, and the radiation can penetrate the coating, which is conducive to the complete curing of the thick film. Three new photoinitiators of phthaloylphosphonium oxide, including photoinitiator 819, photoinitiator 1800 and photoinitiator 1700, were introduced in experiments, and their structure and photodecomposition mechanism were discussed by means of UV-visible spectrophotometry. These three efficient photoinitiators can be used to synthesize polyacrylic acid-acrylic superabsorbents by ultraviolet (UV) photopolymerization. The effects of exposure time and photoinitiator content on the water absorption properties of the resins were comprehensively compared. The results showed that the photoinitiator 819 had the highest activity, the system was basically polymerized completely after exposure for only 1 min, and the monomer content was only 2.55%. In the early stage of the reaction, due to the high activity of the photoinitiator 819, the polymerization product is mainly a linear polymer with small molecular weight, and the crosslinking rate is very low. Only under 20min exposure can a water-absorbing polymer with a crosslinking rate of 83% be obtained.

In addition, photoinitiator 819 can also be used in colored UV-curable plastic coatings. UV coatings have been widely used in plastic casings of various electronic and home appliances due to their excellent performance and efficient production. However, UV coatings add color. After the deep curing is not good, the adhesion of the coating film is poor, and the dispersion and arrangement of the UV resin to the pigment is poor, which seriously affects the appearance of the coating film. Therefore, the traditional construction process is to first coat the solvent-based colored primer for coloring, and then bake it. Then apply UV varnish to improve various physical properties of the paint film surface. The preparation method of colored UV-curable plastic coating is carried out under the condition of shielding light at room temperature, and it comprises the following steps:

1) Photoinitiator 184, photoinitiator TPO and photoinitiator 819 are dissolved in an environmentally friendly solvent to obtain a photoinitiator solution, which is ready for use;

2) Add the hexafunctional aliphatic urethane acrylic resin, the tetrafunctional aliphatic urethane acrylic resin and the difunctional aliphatic urethane acrylic resin into the mixing tank, and stir for 8-15 minutes;

3) In the aliphatic polyurethane acrylic resin of step 2), add adhesion promoter, wetting and leveling agent and anti-settling aid while stirring, and stir for 8-15 minutes after adding;

4) In the material of step 3), add the photoinitiator solution of step 1) while stirring, and stir for 8-15 minutes;

5) Under stirring, add pigment slurry to the material in step 4) for color matching, and then filter to obtain the colored UV-curable plastic coating of the present invention.