UV-curing 3D printing is considered as the most precise and most efficient modeling and forming technology in the 3DP field. Main problems of this material are poor toughness and high cured volume shrinkage.
Commonly used prepolymers can be divided into the following types, and their performance characteristics are also different.
The commonly used cationic prepolymers are epoxy resins and vinyl ether resins. Vinyl ether resins have a narrow application range due to their slow curing speed. Epoxy resins are divided into two categories: glycidyl ether (or ester) epoxy resins and cycloaliphatic epoxy resins. Glycidyl ether (or ester) epoxy resins have always been at a disadvantage in the field of cationic UV curing due to their low activity, slow reaction and low molecular weight of the resulting polymer. Cycloaliphatic epoxy resins have always been in a dominant position in the field of cationic UV curing due to their high activity, small shrinkage during reaction, low viscosity and low toxicity, etc.
Syna-Epoxy 28 is a standard cycloaliphatic epoxy resin suitable for use in many applications, where higher viscosity or more flexible films are required.
According to the research, some scholars choose epoxy acrylate EA and cycloaliphatic epoxy resin S-28 as prepolymers. Since the viscosity of S-28 is lower than that of EA, increasing its dosage will inevitably lead to a decrease in the viscosity of 3D printing materials. S-28 participates in the UV-curing reaction by cationic polymerization, and its UV-curing speed is slower than that of free radical systems. With the increase of S-28 dosage, the UV-curing speed of 3D printing materials decreases. The volume shrinkage rate of free-radical epoxy acrylate prepolymer is larger than that of cationic epoxy resin prepolymer when it participates in the polymerization reaction. As the dosage of S-28 increases, the volume shrinkage rate of 3D printing materials decreases.
After a large number of experimental studies and summary analysis, when the prepolymers EA and S-28 with good mechanical properties are selected, the diluents TMPTMA and DVE-3 can offer a better dilution effect. The photoinitiators ITX and Irgacure 250 are highly efficient in initiating free radical/cationic hybrid UV-curing systems. The co-initiator 6420-TF and polyhydroxy compound PAS-12 are also used as the main component of the high toughness hybrid cured 3D printing material.
Nantong Synasia New Material Co., Ltd. is the world's leading manufacturer of cycloaliphatic epoxy resins. We can provide a variety of product grades such as S-06E, S-21, S-28, etc. Welcome all customers to contact or call us.