| 摘要 |
PCT No. PCT/EP97/00805 Sec. 371 Date Jan. 15, 1999 Sec. 102(e) Date Jan. 15, 1999 PCT Filed Feb. 19, 1997 PCT Pub. No. WO97/31957 PCT Pub. Date Sep. 4, 1997A method of forming a urea formaldehyde resin includes the step of heating solid paraformaldehyde to a temperature of 60 to 120 DEG C. Urea is added to the heated paraformaldehyde to form a urea mixture, which is dry mixed and heated until a temperature of 80 to 110 DEG C. has been reached. After this, a methanolic quanine base is added to the urea mixture to form a quanine-urea-formaldehyde mixture, which is heated until the quanine-urea-formaldehyde mixture is liquefied and cooled to 65 DEG C. Then, the quanine-urea-formaldehyde mixture is heated until it boils, at which point it is condensed for a period of 30 to 100 minutes. After this, additional urea is added to the liquified urea mixture to form a urea enriched mixture. The urea enriched mixture is condensed for 90 to 180 minutes. After condensation, the urea enriched mixture is buffered with lactic acid to form a buffered mixture. This buffered mixture is cooled.
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