Reduction of formaldehyde emission from plywood using composite resin composed of resorcinol–formaldehyde and urea-modified scallop shell nanoparticles

More than 200,000 tons of scallop shells are disposed annually 1 alone in Japan. Nanoparticles derived from scallop shells have the potential to adsorb gaseous formaldehyde; therefore such discarded shells have now been tested as additive filler in plywood adhesive by mixing high specific surface area, urea-modified shell nanoparticles with a resorcinol?formaldehyde resin; with this procedure it was found that the emission of formaldehyde from the resulting plywood could be substantially reduced. The urea-modified scallop shell nanoparticles were prepared by two different methods: (i) by a dry method in which the shells were treated with planetary ball-grinding under ambient conditions ? a completely dried powder was obtained after addition of the surface-modifying urea solution; (ii) by a moist method by treating dry-ground shell particles in a wet grinding process with the urea solution, followed by the use of centrifugation to obtain a paste. The specific surface area of the nanoparticles obtained by both treatments was 42 ± 3 m213 /g. Measurement of the subsequent formaldehyde emission showed that the addition of the modified scallop shell nanoparticles substantially reduced the formaldehyde emission from plywood; the reduction depends from the specific mass uptake of urea on the nanoparticles which especially was the case when resins containing nanoparticles processed by the moist method were used

ホタテ貝殻の微粉化と合板用接着剤からのホルムアルデヒド放散量低減効果

application/pdfScallop shells are disposed more than 200,000 ton per year in Hokkaido. Here we report effective uses for discarded shells as an additive of plywood adhesive because some plywood adhesives emit formaldehyde that leads to limit on its use. We produced adhesive resin filling ground shell particles with a high specific surface area to reduce formaldehyde emission from plywood. Nano-sized scallop shell particles were prepared by planetary ball milling under dry condition and subsequent water addition. The emission amount of gaseous formaldehyde from plywood was then estimated. We found that the prepared adhesive including scallop shell nanoparticles exhibited an excellent inhibiting effect on the formaldehyde emission rather than the feed shell