Reacting Technique Of Urea-formaldehyde Resin With Initial Weak Acidity Condition

At present, the technique of UF resin is mainly the traditional synthetic technique ofbasic-acidic-basic. UF resin is modified with melamine by the traditional synthetic techniqueof basic-acidic-basic to improve the resist of water and moister of UF resin. However, thesynthetic technique of basic-acidic-basic is only to decrease the mole ratio of F/U or F/(M+U)and to add to modifiers which are used to improve the quality of UF and MUF resin and lowthe formaldehyde emission with the chemical price growing, the means which decrease themole ratio of F/U or F/(M+U) and add to modifiers are not advantage of cost. So the newsynthetic technique is studied at high the mole ratio of F/U or F/(M+U) and the quality of resinand board to reach to the standard of government. This is important meaning to the syntheticUF resin and board of enterprise.With studying on the synthetic technique of UF resin with different weak acidity, thecharacteristic of synthetic technique and the quality of it was understood. The synthetictechnique of UF resin with initial weak acidity condition was ascertained. By using theorthogonal test, the results were analyzed by variance analysis, and the optimum for synthesisUF resin finally was found. UF resin is modified by melamine with the synthetic technique ofUF resin with initial weak acidity condition. The quality of MUF resin and plywood whichwere made of MUF resin reached the standard of GB/T9846.7-2004. Aslo, with differentcuring agent the curing procedure of UF resin which was synthesized under initial weak aciditycondition was studied. One kind of good properties, low cost curing agent cost was concluded.The chemical group, functional group, resin curing and the rule of formaldehyde emissionof plywood were studied by DSC, FTIR and UV in details.When the mole ratio of F/U is the same as common UF resin, the amount of methyleneand aether bond in UF resin which was synthesized under initial weak acidity condition wasmore than common UF resin. The Formaldehyde emission of UF resin of plywood lower thancommon plywood. At higher the mole ratio of M/U, the quality of MUF rein and the propertiesof plywood could reach to the requirement of government. The curing effect of different curingagent is different to UF resin. The formaldehyde emission and bond strength of plywood isdifferent, too. The results showed the characteristic reaction of synthetic technique of UF resinwith initial weak acidity condition and cured UF resin. It has practical function on applicationof synthetic technique of UF resin with weak acidity condition.