| With advantages of high efficient, energy saving, environmental friendly, enabling and so on, UV-curing ink and adhesive have broad prospects in the packaging. However, there is a serious problem that photoinitiators and their fragments tend to migrate to the packaged goods and pollute the goods when UV-curing products using in the food and drug packages. It will have an important significance in the application of UV-curing products in food and drug packaging to research polymerizable photoinitiators. Polymerizable photoinitiators developed always have poor storage stability. So it urgently needs to develop polymerizable photoinitiators with good storage stability to solve the problem.The electron-rich double bonds of vinyl ether are not easily to be triggered homopolymerization by free radicals. However, when added to the UV curing system such as acrylate, vinyl ether can polymerize with other monomers or prepolymers. Based on the characteristics of the vinyl ether, introducing the vinyl ether group to a radical photoinitiator to prepare a vinylether-terminated radical UV photoinitiator will not be easily to gel by self-generated polymerization and have an excellent storage stability. At the same time, it can polymerize in the UV-curing systems. In the progress of introducing the vinyl ether groups, we must pay attention to the photoinitiator’s structure-function relationship. When the α-hydroxyl group of the α-hydroxy ketone photoinitiator has been reacted, photoinitiator efficiency will be greatly reduced. Under the guidance of these theories, a novel polymerizable vinylether-terminated photoinitiator, HT-2959, with good storage stablility was synthesized from diisocyanate,4-hydroxybutyl vinyl ether, and 2959. Based on the different of the reaction activity between the primary hydroxyl group and the a-position tertiary hydroxyl group, it can protect the α-position of the hydroxyl group not being reaction. The effect of solvent in the first step reaction has been discussed and the molecular structure was characterized by FT-IR and 1H-NMR in this paper. The UV absorbing property, the ability to decompose, the initiator efficiency, the stability and low mobility of the HT-2959 have also been studied in this paper. It also discusses the relationship of the photoinitiator structure of the α-hydroxy and efficiency. And the application of HT-2959 in the UV curing adhesives using for the laminated film was explored. The results and conclusions are as follows:(1) The result of the synthesis process of HT-2959 shows that, it has a high conversion rate 100% in the synthesis process, yield is 66.6%, and adding solvent will led to the decrease of the reaction rate and conversion rate in the first-stage reaction.(2) Compared with 2959, HT-2959 has the similar maximum UV absorption peak at 275nm, higher molar extinction coefficient (ε=1.608×104L/mol.cm) which indicates a good ability in ultraviolet absorption, and similer abilities in photolysis and triggered polymerization, which indicates HT-2959 having a high photo-initiation efficiency.(3) Vinyl ether is more stable than acrylate exposured to UV light which gives HT-2959 a high stability. While, mixing vinyl ether and acrylate can make vinyl ether polymerize in UV irradiating which gives HT-2959 a low migration ability.(4) Prepared with adhesives using HT-2959 as a free radical initiator for laminating PET film and PE film, the T peel strength can reach 2.11N/15mm which is arriving at the related packaging standard. |
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