Radiation Curable Resin Composition

In order to reduce the time to biuld a part via a stereolithography process, modem stereolithography machines require a more versatile liquid radiation curable resin composition. 

A liquid radiation curable resin capable of curing into a solid upon irradiation has been described that contains a cycloaliphatic epoxide with a linking ester group, oxetanes, polyols, methacrylate components, impact modifiers and photoinitiators (33). 

Medical applications of inkjet technology, e.g., drug delivery, have been detailed in a separate chapter. Here we focus on medical applications of 3D printing. 

The potential impact on biotechnology of 3D printing has been reviewed (34). 

The uses and applications of 3D printing for tissue engineering have been reviewed (35). Also, biodegradable materials can be printed that have proven ideal for bone tissue engineering, sometimes even with site specific growth factor and drug delivery abilities. 

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J. Southwell, B.A. Register, S.K. Sarmah, P.A.M. Steeman, B.J. Keestra, and M.M. Driessen, Radiation curable resin composition and rapid three-dimensional imaging process using the same, US Patent... 

Multifunctional photoinitiators, (II), were prepared by Sommerlade et al. (2) for radiation-curable dental compositions using UV light. A Norrish Type visible-light-sensitive multifunctional ketopinic amide derivative attached to a modified amino-silanated resin, (III), was prepared by Condon et al. (3) and used as a macroinitiator in dental applications. 

FP is not currently in commercial use, although there have been several patents issued related to it. The first is for an In depth curing of resins induced by UV radiation, which used a combination of UV hght to start free-radical FP [63]. In 2001, Gregory patented Ultraviolet curable resin compositions having enhanced shadow cure properties in which the frontal curing of cycloaliphatic epoxides was achieved with a cationic photoinitiator in tandem with a peroxide [64]. Pojman was awarded two patents on functionally gradient materials prepared by FP [65, 66]. The maker of chemical anchors, Hilti, has two patents on FP but has not commercialized either of them [67, 68]. 

Radiation-curable liquid resin compositions were prepared by Takahashi et al. 

The papers presented in the following chapters represent advances in pressure sensitive adhesives (ultraviolet light activated acrylate monomer - low Tg polyether formulations) photoinitiated cationic polymerization (light activated aryliodonium and arylsulfonium salts of lewis acids in epoxy resin formulations) polymer and formulation design criteria for radiation curable adhesives radiation curable composites (dynamic thermal analysis characterization of electron beam cured... 

Radiation curable technology involves the usage of 100% solid material and thus does not require solvent-based adhesive compositions. The substrate is coated with a low-viscosity liquid resin using conventional techniques. With increase in viscosity, the development of cross linking as well as visco-elastic properties is accelerated by exposing the moving substrate to a radiant energy source. 

Table 3 lists the selected properties [16] that we have measured for several commercially available acrylate resins manufactured by the Sartomer Company and the Rohm and Haas Company. The resins were cured in an AECL Gammacell Model 240. The temperature rise was measured for an 8-g sample using Acsion s (formerly AECL Radiation Applications Branch) Gamma Calorimetry method [17]. All of this information is being used to evaluate the applicability of EB-cured acrylate adhesives for repairing composite structures. Combinations of these adhesives can be used to create electron-curable adhesives suitable for composite repair. 

Janke, C.J., Dorsey, G.F., Havens, S.J. and Lopata, V.J., Toughened epoxy resins eured by eleetron beam radiation. 28th International SAMPE Technical Conference, S71, 1996. Janke, C.J., Electron beam curable cationic epoxy resin systems and composites. 1st Annual Electron Beam Curing of Composites Workshop, September 18-19, Oak Ridge, TN, Ref. ID, 1996. 

Lopata, V. J., Saunders, C. B., Singh, A., Janke, C. J., Wrenn, G. E., and Havens, S. J. (1999). Electron-beam-curable epoxy resins for the manufacture of high-performance composites. Radiat. Phys. Chem., 56 405. 

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