Contact sensitization to organosilane solution in glass filament production
Glass filaments have been commercially produced since the 1930s, and are now mainly used for reinforcing plastics, paper, textiles, floorings, boats, and bituminous products, and rendering appliances like pipes and tanks corrosion-resistant. During production, filaments are coated with a water dispersion of epoxy resins, polyester resins, silane compounds, emulsifiers, lubricants, surfactants and antistatic agents. Various silanes are used as bonding agents between glass and resin in the final product. 2 studies have recently reported sensitization to silanes (1, 2).
Contact allergy to allyl glycidyl ether present as an impurity in 3-glycidyloxypropyltrimethoxysilane, a fixing additive in silicone and polyurethane resins.
We present a 43-year-old man who worked in the plastics industry and who suffered from an occupational dermatitis on the hands and forearms. He was found to be allergic to an epoxy silane compound that was contaminated with allyl glycidyl ether, a reactive epoxy diluent. HPLC analysis and patch testing indicated that this impurity was probably the only sensitizer. Moreover, the gloves used provided absolutely no protection, as the inner side also generated strong positive reactions.
Evolution of carbide precipitates in Hastelloy N joints during welding and post weld heat treatment
Abstract The effects of welding and post weld heat treatment (PWHT) on the morphology, composition and lattice parameter of the precipitates in the welding joints of Hastelloy N alloy have been investigated. Joint samples were prepared using a gas tungsten arc welding process with ERNiMo-2 fillers, and then solid-solution treated at 1100 °C for 20 min. After welding, eutectic M6C carbides can be observed in the heat affected zones (HAZ) and weld zones (WZ). These eutectic M6C carbides become spheroidized during the following PWHT. The concentration of Si decreases during the transformation from the primary ones to eutectic ones, and then increases during the spheroidizing process. The total concentration of Si + Cr in M6C carbides remains stable during welding and PWHT. At the same time, the heat leads to the outward diffusion of Mo from the M6C carbides, which results in a decrease of the lattice parameter.