Abstract:

HCHO was introduced as the cross一linking agent when LGV type chrome-
free lignosulfonate thinner was synthesized.The cross一linking function of
HCHO，the relationship among the dosage of HCHO and the intrinsic vis-
cosity，the adsorption，salt-resistant and the thinning properties of LG V
sample were examined by means of infrared spectroscopy, scanning elec-
tronic microscopy，viscosity, precipitate，adsorption and mud experiments.
The results showed that HCHO had the crosslinking function and affected
the adsorption，hydration and thinning properties of LG V sample by ma-
inly affecting the average molecular weight.Therefore，it is necessary to
control and adjust the dosage of HCHO.

Key words: Lignosul fonate mud Additive Thinning agent Cr