UV Photoinitiators’ appliacation in UV inks
UV inks are mainly composed of photopolymerizable prepolymers, photosensitive monomers, photoinitiators, organic pigments, and additives. In addition to the use of UV inks for printing, attention should be paid to coloring, curing, and adhesion. It is also necessary to pay attention to the influence of ink components on ink viscosity and rheology in order to obtain better printability and stability. The basic meaning of radiation curing is to use ultraviolet (UV) or electron beam as energy source to initiate a chemically active liquid formulation to achieve rapid reaction curing process on the surface of the substrate. Industrial applications of UV/EB curing provide an advanced processing tool for surface curing of materials. The biggest advantage of this curing technology over traditional technologies (such as thermal curing) is that radiation curing uses a high-efficiency energy source—ultraviolet light or electron beam as the initiator—to quickly achieve coating cure. Due to its highly efficient and green features, applications are becoming more widespread.
Ultraviolet light and electron beam can be regarded as members of a large family of radiation. The difference is that ultraviolet light is an electromagnetic radiation, and the electron beam is an accelerated high-energy electron flow. The 100-380 nm UV region commonly used for radiation curing is subdivided into UV-C (100-280 nm), UV-B (280-315 nm) and UV-A (315-380 nm). The ultraviolet light source used for radiation curing is generally an ultraviolet lamp excited by electric energy. Electron beam is also a kind of radiation. It is a group of accelerated electron currents. The energy of particles is much higher than that of ultraviolet light, which can ionize air. Therefore, high-energy electron beams can also be called ionizing radiation. Electron beam curing generally does not require photoinitiators and can initiate chemical reactions directly, and the penetrating power of substances is also much greater than that of ultraviolet light. The device that generates the electron beam is called an electron accelerator. A scan-type electron accelerator used for radiation curing has a basic principle similar to that of a home-use television. In the television, the accelerated electron flow scans the television screen to obtain visual information, and the electron beam of the electron accelerator in the radiation curing scans the surface of the substrate to achieve curing processing.
The process conditions for the synthesis of urethane acrylate prepolymers were studied. The molecular weight distribution of the products and the rheological properties of the prepolymers were determined. The different types of photoinitiators and different amounts of photoinitiators were determined by using a universal material testing machine. With different types of diluents on the pressure-sensitive adhesive bond peel strength.
UVCC consists of photosensitive resins (oligomers), reactive monomers, photoinitiators, and various types of additives. The oligomers are low molecular weight resins containing C=C unsaturated double bonds, mainly unsaturated polyesters, epoxy acrylates (EA), urethane acrylates, polyester acrylates, polyene/thiol systems, poly Ethyl Acrylate, etc. Photoinitiator 184 is a highly effective free radical type I non-yellowing photoinitiator for UV polymerization of mono- or polyfunctional groups. Polymeric acrylate monomers and oligomers are widely used in copy varnishes, plastic coatings, wood coatings, adhesives, lithographic printing inks, wire mesh, etc.