13 августа, 2015 
Malyar The adhesive developed for the manufacture of damp-ply-resistant corrugated cardboard are based on the addition of spray-dried wattle extract, urea-formaldehyde resin, and formaldehyde to a typical Stein-Hall starch formula of 18 to 22% starch content [60,61]. The wattle tannin-urea-formaldehyde copolymer formed in situ, and any free
formaldehyde left in the glue line is absorbed by the wattle tannin extract. The wattle extract powder should be added at a level of 4 to 5% of the total starch content of the mix (i. e., carrier plus slurry). Successful results can be achieved in the range of 2 to 12% of the total starch content, but 4% is the recommended starting level. The final level is determined by the degree of water hardness and desired bond quality. This wattle extract-urea — formaldehyde fortifier system is highly flexible and can be adopted to dampproof a multitude of basic starch formulations.
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