Ureo-formaldehyde resins

The main raw materials used for the synthesis of ureo-formaldehyde resins are urea and formaldehyde. Urea is a solid, crystalline, water-soluble substance. It has a weak basic character. Formaldehyde is used in solution form at 30-55% concentration. It is of advantage to use either high-concentration formaldehyde solutions or precondensates. Both processes provide a satisfactory economic efficiency and diminish residual water content. Precondensates can be obtained through the reaction between urea and formaldehyde (molar ratio 1 1.1-6), at T = 45 C and pH = 6.8-8.0 [19]. 

The conversion of ureo—formaldehyde resin that is soluble in water to an insoluble open pore urea—formaldehyde material involves the following reactions... 

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