Radiation curable material

Screen printing of UV inks is being done over paper, metal, films, foils, plastics, and PVC. Radiation curable materials are being used as vehicles for ceramic inks that are screened onto automotive windshields, cured, and then fired in an oven to bum off the organic binder and fuse the ceramic into the glass windshield. ... 

Practical radiation curable materials are composed of more than a single reactive monomer. Commercial adhesives normally contain the following ... 

The majority of radiation curable materials are derived from or consist of acrylic and methacrylic unsaturated monomers, oli-gonomers, and polymers (including unsaturated polyethers) which cure through free radical addition-propagation reactions. 

Wood panel was coated with radiation curable materials and then irradiated using EBM. Radiation curable material is a liquid materials which contains mainly a solution of oligomers in polyfunctional monomer and a small amount o1 additive i.e pigment. Polymerization will takes place under E9 radiation forming a hard ccating of solid polymer. Example of radiation curable material is solution of epoxy acrylate in tripropylen glycol diacrylate. 

Increasing amounts of radiation curable materials are being used in coating films for the surface refinement of furniture, wooden floor coverings, paper, etc. Confocal Raman spectroscopy of UV-cured films may be used to examine depth or lateral profiles of the cross-linking process in coatings with a resolution of approximately 1 [549]. The... 

Radiation-curable materials United States 3,281,263 1966 Dow Chemical... 

While the chemistry of radiation curable hot melt adhesives is the same as that used in liquid (syrup) adhesives and coatings discussed elsewhere in this volume, there is a fundamental difference between the objectives of reaction in the two types of systems. Syrups consist largely or entirely of reactive monomeric and/or oligomeric materials. Radiation is used to initiate the polymerization of virtually the entire mass. In contrast, hot melts generally contain polymers initially, and these polymers are capable of reaction via radiation to produce chain extension and... 

Optical fibers are widely used in the telecommunication industry for fhe fransmission of digital pulses of voice, video, and dafa. In order to keep losses in signal strength at a minimum, the fiber (usually a doped silica glass) has to be coated with a material of lower refractive index than its own refractive index. This layer is protected by a "buffer," which acts as a cushion. The buffer is encased in one or more protective layers (see Figure 7.18). Both the primary and protective coatings are very often UV radiation curable. 

To be suitable for radiation-curable powder coatings, materials must contain unsaturated double bonds. They may contain acrylic or methacrylic unsaturations, but nonacrylate systems can also be used.32 The latter are based on the same chemistry... 

The type of crosslinking achieved with electron beam and uv radiation is very similar, but the way curing initiates is different. Electron beams have the higher energy, and the electron itself has sufficient energy to initiate polymerization. In uv curable materials, the polymerization reaction is not directly initiated by uv light, and a photoinitiator is required to interact with the uv radiation and produce the initiating species. 

Epoxy acrylates are dominant oligomers in the radiation curable adhesives market. A bisphenol A epoxy resin is reacted with acrylic acid or methacrylate acid to provide unsaturated terminal reactive groups. The acrylic acid-epoxy reaction to make bisphenol A diacrylate destroys any free ingredients such as epichlorohydrin used to make the DGEBA epoxy starting raw material. 

Monomers are primarily used to lower the viscosity of the uncured material to facilitate application. The monomer must be matched with the resin to give the desired set of properties with respect to adhesion to the substrate and bulk properties such as flexibility, stiffness, cure behavior, and durability. Early radiation curable monomers had problems associated with toxicity and skin sensitivity newly developed monomers have been significantly improved in this respect. 

Most of the radiation curable raw material technology is based on acrylic or methacrylic acid deritive but may also include modified epoxies, polyesters, and polyurethanes. Thus the backbones of radiation curing and conventional coatings are similar. 

Examples of some typical prepolymer materials and their raw material derivatives are given in Table I. Polymer manufacture schemes for radiation curable and conventional coatings are in Figures I and II. Qualitative comparison of a relative energy input intensity for preparation of radiation curable and conventional coatings are given in Tables II, III, and IV,... 

The point to be made is that most coating building blocks, conventional or radiation curable, come from approximately the same raw materials sources. The overall energy input for a manufacturing process involving conventional polymers is very similar or can be equivalent to manufacture of a radiation curable polymer system. In some cases there may be, however, an added processing step for the radiation curable polymer in order to include reactive functionality. 

In almost all cases a radiation curable polymer can be manufactured under the same conditions as conventional solvent based coatings except for special handling of possible toxic materials. Thus, differences in total energy requirements for both manufacturer and use (application and cure) are directly relatable to the energy consumed in application and curing. 

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