Radiation curing applications

Over the years, a number of compounds have been identified to photoinitiate cationic polymerization of monomers designed for radiation curing applications generally, and negative-resist applications specifically. The most prominent of these initiators are onium salts. 

Uses. Acrylics, both lacquers and enamels, were the topcoats of choice for the automotive industry from the early 1960s to the middle 1980s. Thermosetting acrylics are still used by the major appliance industry. Acrylics are used in electrodeposition and have largely replaced alkyds. The chemistry of acrylic-based resins allows them to be used in radiation curing applications alone or as monomeric modifiers for other resins. Acrylic-modified polyurethane coatings have excellent exterior durability. 

The successftil preparation of hydroxyl functional NVF derivatives opened another option for preparing monofunctional resins for use as macromers or difunctional iV-vinylformamide terminated resins for radiation cure applications (see below). 

UV-radiation curing has become a well-accepted technology which has found numerous industrial applications because of its distinct advantages 1-3. One of its main characteristics is the rapidity of the process which transforms quasi-instantly the liquid resin into a solid polymer under intense illumination by a UV-source or a laser beam4. The polymerization rate can be finely controlled by acting on the initiation rate through the intensity of the UV radiation. It is... 

The main potential for expansion of UV/EB into aerospace and certain commercial applications is by developing radiation curing of polymeric fiber-reinforced composites. The initial work on composite skin repairs involve applying the UV curing technology with bisacryl phosphine oxide to ensure the cure of relatively thick layers. A total of ten layers were used at a time. The UV cured composites closely matched those produced by heating. ... 

Excimer and nitrogen lasers are sources of pulsed monochromatic UV radiation with a variety of interesting wavelengths and high output peak powers. However, they cannot compete with mercury arc lamps in large areas or fast-cure applications because of their low pulse repetition rates.9... 

The major use of vinylpyrrolidinone is as a monomer in manufacture of poly(vinylpyrrolidinone) (PVP) homopolymer and in various copolymers, where it frequently imparts hydrophilic properties. When PVP was first produced, its principal use was as a blood plasma substitute and extender, a use no longer sanctioned. These polymers are used in pharmaceutical and cosmetic applications, soft contact lenses, and viscosity index improvers. The monomer serves as a component in radiation-cured polymer compositions, serving as a reactive diluent that reduces viscosity and increases cross-linking rates (see... 

Higher alkyl acrylates and alkyl-functional esters are important in copolymer products, in conventional emulsion applications for coatings and adhesives, and as reactants in radiation-cured coatings and inks. In general, they7 are produced in direct or transesterification batch processes (17,101,102) because of their relatively7 low volume. 

Perfluoroelastomers (ASTM designation FFKM) are essentially copolymers of two perfluorinated monomers, TFE and PMVE with a CSM, which is essential for cross-linking. Perfluoroelastomers can be cured by ionizing radiation without any additives. The advantage of radiation cured FFKM is the absence of any additives, so that the product is very pure. The disadvantage is the relatively low upper-use temperature of the cured material, typically 150°C, which limits the material to special sealing applications only [32]. 

Application areas for radiation curing have been reviewed and... 

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