Lignin based binder prodn. from black liquor or thick liquor - by concn. of liquor, addn. of alkali, addn. of phenol and formaldehyde or para:formaldehyde and condensn.

摘要

In the prepn. of a lignin-based binder with viscosity 60-2000 mPa.s, by condensn. with phenol and HCHO or paraformaldehyde, (a) black liquor or thick liquor from the "Asam" (RTM) or "Organosol V" (RTM) processes is conc., (b) the pH is brought to 13-14, (c) 8-30% of phenol, and 12-40% of HCHO or 4.5-15% of paraformaldehyde (all w.r.t. solids content of the binder) are added, and (d) the mixt. is condensed at the b.pt.. Pref. the amts. added are 20-28% of phenol, 18-30% of HCHO, and 6-10% of paraformaldehyde. USE/ADVANTAGE - The binder is esp. used in making wood prods., e.g. chipboard and plywood, and flat textiles, e.g. fleeces, and in binding inorganic particles. A high quality binder is prepd. directly from the liquors, avoiding isolation of the lignin, and utilising chemicals (e.g. alkali hydroxide and K2CO3) present in the liquors. The binder has less excess HCHO than urea resins, and less HCHO is given off by the wood prods.. Bonded plates are more resistant to boiling that plates bonded with urea resins. (5pp Dwg.No.0/0)