METHOD OF PREPARING PHENOL-UREA-FURAN BINDER Russian patent published in 2006 - IPC C08G8/28 B22C1/22 

FIELD: polymer production.

SUBSTANCE: invention concerns technology of production of phenol-urea-furan resins used as binder in cold-cured in core sand mixtures and sand blends for cast iron and steel castings. Preparation of binder includes condensation of urea-formaldehyde concentrate (20.5-25.0% urea, 54.5-60.0% formaldehyde, not more than 0.3% methanol, and water) with urea on heating in a variable-acidity aqueous solution. Thus synthesized urea-formaldehyde resin is mixed with phenolalcohol (obtained by condensation of phenol with formalin to achieve refraction coefficient 1.454-1.472) at resin-to-phenolalcohol weight ratio 1:(2.2-;2.5) and resulting mixture is subjected to vacuum drying and modification in presence of furyl alcohol, which is added in two steps: 20-50 wt parts per 100 wt parts phenolalcohol during vacuum drying and 70-90 wt parts per 100 wt parts phenolalcohol after vacuum drying by way of diluting resin.

EFFECT: optimized urea-furan binder synthesis conditions and improved properties of sand-resin composition based on this binder.

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