Study of viscosity behavior and retanning properties of sulfonated glutaric dihydrazide formaldehyde condensate under different reactant ratios

Sulfonated glutaric dihydrazide formaldehyde condensates with less than 0.05% free formaldehyde were prepared through controlled reaction of glutaric dihydrazide, sodium metabisulfite, and formaldehyde in three processing steps. Mole ratio of sodium metabisulfite/glutaric dihydrazide (S/GDH) was varied from 0.1 to 0.5 and that of formaldehyde/glutaric dihydrazide (F/GDH) from 1 to 3. The effects on viscosity and fluidity of resins were observed with varying degrees of sulfonation and changeable mole ratio of formaldehyde/glutaric dihydrazide. Viscosity of resins showed increasing trend with increasing mole ratio of formaldehyde/glutaric dihydrazide and decreasing trend with increasing mole ratio of sodium metabisulfite/glutaric dihydrazide. Increase in viscosity of resins was due to increase in molecular weight of polymer chains. After gaining a critical molecular weight during condensation, resins turned into gel form. The resins were comparatively applied on chrome tanned cow hide against commercial sulfonated urea formaldehyde powder resin (Resin UFT).