Study On Synthesis And UV-curing Reaction Of Polyol Acrylate

Technology of UV-curing is energy-saving and environmentally friendly. Compared with traditional curing, the technology has wider developed foreground because of some advantages such as fast curing rate, less energy consuming, little pollution, and high efficiency. The UV-curing system usually consists of photosensitive monomer or prepolymer and photo-initiators. Polyol acrylate is a high reactive monomer and important thinner in UV-curing. In this paper, pentaerythritol triacrylate (PETA) and dipentaerythritol pentaacrylate (DPEPA) were synthesized and studied.The PETA and DPEPA were prepared by esterification based on acrylic acid, pentaerythritol and dipentaerythritol with the addition of the catalyst, inhibitor and solvent. The effect of catalyst content, inhibitor content, molar ratio of acrylic acid and alcohol, reactant concentration on the yield of the product were discussed. The optimum conditions of synthesizing PETA were obtained by a series of experiments was as follows: the mole ratio of acrylic acid and pentaerythritol was 3.6, catalyst content was 2.0%, inhibitor was para-methoxy phenol and thlodiphenylamine, its content was 1.5%, reactant concentration was 50%. The optimum condition of synthesizing DPEPA was as follow: the mole ratio of acrylic acid and dipentaerythritol was 5.8, catalyst content was 2.5%, inhibitor was 4-hydroxy-2,2,6,6–tetramethyl-4 -piperidinyloxy free radical and para-methoxy phenol, its content was 2.0%, reactant concentration was 45%. The structure of PETA and DPEPA was identified with IR and HPLC.The UV-curing processes of DPEPA was monitored by measuring the variation in double bond content at 1635 cm-1 with IR spectrometry in which the standard is peak value of carbonyl. The initiating efficiency of different photoinitiators and various factors affecting the photocuring reaction were examined. It was obviously found that the efficiency of 2-methl-1- [4-(methsulfur)phenyl]-2-morpholinal-1-acetone(Iracure 907) is higher than that of benzophenone (BP). With the content increasing of IR907, the speed of the conversion of double bond content increased first and minished afterwards, but later got flat. The optimum content was about 5% of the monomer.In addition, the curing and sintering of the photosensitive system in which added organic carrier and ultrafine glass powders were investigated.