Preparation And Properties Of Novel Transoarent And Non-Yellowing Photosensitive Resins For 3D Printing

Three-dimensional(3D)printing is a process of making 3D objects by successively superimposing layer by layer.Among various 3D printing methods,photochemical polymerization methods are very attractive because objects with complicated shapes can be directly produced by photopolymerization of photosensitive resin materials,which has the characteristics of low cost,easy production and no pollution.The manufacture of high-precision 3D printers and the preparation of high-performance photosensitive resin materials are two important aspects in the development of photochemical 3D printing.At present,3D printers at home and abroad have matured,but the development of photosensitive resin materials is slow,especially in China,and there are still few high-performance photosensitive resin materials produced by ourselves.This paper includes the following.The paper first introduces the research status of 3D printers and photosensitive resin materials,and focuses on the development and inadequacies of photosensitive resin materials.The analysis shows that the photosensitive resin material with good transparency and not yellowing is the most lacking and most important basic material at present.Therefore,it is of great significance to develop a photosensitive resin material which is transparent and does not yellow.The effects of different types of photoinitiators,diluents and oligomers on the properties of bright resins were investigated.It was found that no matter whether it is a benzene ring-containing resin system capable of producing a chromophore group or an aliphatic resin system having anti-yellowing properties,there is nophotosensitive resin which is completely transparent and does not yellow,and the mechanical properties are added with the diluent.And lower.This is due to the fact that the viscosity of the oligomer is too large,and a large amount of small molecule diluent needs to be added,resulting in a decrease in the accuracy,mechanical properties,transparency of the 3D printed sample,and yellowing of the material.Therefore,this study considers whether it is possible to use oligomer-free or oligomer-free systems to produce photosensitive resin material with better mechanical properties,transparency and without yellowing by using rigid monomers to replace oligomers with appropriate viscosity,reducing the amount of diluent,reducing the proportion of small molecules in the material.A rigid monomer with a reactive group was synthesized by a two-step process:2-Ethoxybisphenol A Dimethacrylate(2EO-BPADMA).Photosensitive resins with different properties were prepared by comparing 2EO-BPADMA with diluents HEMA and TPGDA,initiators TPO and BDK.Through comparison of curing depth,gel content,viscosity,shrinkage rate and basic mechanical properties of cured samples of different resin materials,a photosensitive resin formula with optimal comprehensive properties was determined.Then add SiO2,JZ-303 and JZ-305 for modification,which can improve the mechanical properties of the material.Through modification,although the mechanical properties are very close to a kind of photosensitive resin of Foto Tec DLP.A type which is better in transparency,the material still has yellowish color.The main reason for the yellowing of photosensitive resin is the presence of small molecules in the system,which are indispensable components of photosensitive resins.In order to solve the yellowing,the main inducing factor of the yellowing of the material was light by the conditional experiment.Then the light stabilizer 622,the light stabilizer 292,the titanium dioxide and the inorganic ultramarine blue were used to completely solve the problem of curing yellowing of the photosensitive resin material.A transparent and non-yellowing photosensitive resin for 3D printing was produced and some research was done.