Coatings, dual cure

Sheet molding compound (SMC) is a composite material that has been used as an alternative to steel for more than 30 years. SMC consists of a glass-fiber-filled unsaturated polyester and vinyl ester resin that has been compacted into a sheet. These sheets are then placed into compression molds and formed into body panels, and these panels are then coated mainly by dual-cure coatings. ... 

Properties of Dual Cured Films. The properties of dual cured films containing the oleamide modified AH and epoxy acrylate were compared. The formulations used oligomers at 65% in TPGOA and included 3% Darocur 1173 and 3% PTSA. They were applied to clay coated board over black lithographic ink with a 3 rod and cured by a UV exposure of 250 mj/cm followed by a thermal cure of 5 minutes at 150 C. The... 

One key to achieving the best combination of stencil profile and surface roughness lies in the selection of the stencil material. The right dual-cure emulsion must be selected for its wet-on-wet coating properties, solids content, and print definition. The fact is that you may have to accept a little give and take between print clarity and ink transfer. In photorealistic CID printing, Rz values for direct emulsion stencils generally are measured on a Rz scale from 4-10. 

Another mode of dual curing involves the simultaneous occurrence of free radical and cationic radiation-induced cross-linking polymerization of formulations containing appropriate initiators [20, 23, 28]. This method, which is called hybrid curing, leads to coatings with imique properties. A typical hybrid-cure system contains a diacrylate and a diepoxide, the former polymerizing by a free radical and the latter by a cationic mechanism. Exposure of the system to in-... 

Recent developments in powder coatings based on epoxy include UV-curable GMA-acrylic coating for antomotive parts lower temperature cure coatings for heat-sensitive substrates such as wood (222,223) and plastics and dual cure (ther-mal/UV) systems. 

Keywords Acrylates Crosslinking Dual cure Epoxides Glass laminates Interpenetrating polymer networks Isocyanates Photo initiated cationic polymerisation Photoinitiators Photopolymerisation Pressure sensitive adhesives Release coatings Structural adhesives Thiol/polyene UV radiation curing Vinyl ethers. 

Decker, C Masson, F. and Schwalm, R., Dual-curing of waterborne urethane-acrylate coatings by UV and thermal processing, Macromol. Mater. Eng., 2003, 288, 17-28. 

Dual cure coatings, based on multifunctional acrylates to which a small quantity of a polythiol has been added, have been proposed as conformal coatings for completed printed circuit boards UV exposure causes a rapid setting of the coating,... 

Dual functionality coatings differ from dual cure coatings in that they contain functional groups of different kinds. In the first step, partial crosslinking is accomplished through exposure to UV light, in the second step another component, for example an epoxide, is cured thermally through the activation of a latent catalyst. 

Malucelli, G. Hybrid organic/inorganic coatings yhrough dual-cure processes state of the art and perspectives. Coatings 6, 10 (2016). doi 10.3390/coatings6010010... 

Sangermano, M., Voit, B., Sordo, F., et al. High refractive index transparent coatings obtained via UV/thermal dual-cure process. Pol5uner 49, 2018—2022 (2008)... 

Pacansky et al. (1987) described the fabrication of dual-layer photoreceptors by radiation curing. The layers were coated with a polymerizable acrylate monomer or oligomer as the liquid component, then cured by a 175 kV electron beam or ultraviolet exposure. These methods were used for the preparation of generation layers containing bisazo and hydroxysquaraine pigments. 

Recently, Endo and coworkers have developed novel sulfonium type initiators that can initiate polymerization either upon irradiation or upon thermal treatment. In addition, these photoinitiators are shown to be functional for both cationic and radical polymerizations. This dual activity is particularly important in hybrid curing systems for coatings and adhesions [28]. Scheme 11.6 contains the general steps for the synthesis of these photoinitiators from sulfides. 

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