Study On Stability Of Melamine-Urea-Formaldehyde Adhesive

This paper studies stability of MUF mixed resin on the basis of the formulation of the fixed UF resin synthesis process. The influences of MF synthetical technology and different modifier on MUF resin stability were discussed. Mainly related to the two aspects of storage stability and thermal stability of MUF mixed resin. It also discusse the other factors on the performance of MUF resin at the same time of explore stability.The influences of synthetical parameters of MF resin such as molar ratio, condensationtime, modifier, diluent contents and storage conditions on MUF resin storage stability were discussed. The experimental results showed:as the mole ratio of reaction F:M increased, the storage stability of MUF resin was improved. When condensation reaction time was extended and pH of storage increased, MUF resin storage life increased at first but then decreased. The modification effect of glycerol which is best in Modifier of the single component can improve the25d of the storage period,and ethanol, ethylene glycol followed. Two-component modifier can control of the reaction process more stable, and significantly improved the storage stability of MUF resin. The dilute could improve the storage stability of MUF resin.,and which stored at room temperature better than the low-temperature storaged, and alkaline storage than acid storage period. When Consider other performance can find that modifier can be appropriately extended curing time.The reaction molar ratio and reaction time affect the formaldehyde emission, as the mole ratio of reaction F:M increased, the release of free formaldehyde is improved. increasing the condensationtime time helps to reduce the content of free formaldehyde.The resin curing behavior and thermal decomposition study were discussed in the thermal stability of MUF mix resin. Experimental results show that the applicable period becomes shorter with the increase of the curing agent. The DSC curves reflect the curing of the resin in advance and lower peak temperature with the increase of the curing agent.In the experiment of dual-curing system, ammonium persulfate-ammonium chloride,formic acid-ammonium chloride system can reduce the curing temperature,curing time and pot life, and phosphate-ammonium chloride system can increase the curing time and pot life,it can control the curing process.The curing time and pot life of three-component hardener of ammonium dibasic phosphate-ammonium chlorideon-urea and diammonium hydrogen phosphate-ammonium chloride-urea are longer than three-component hardener of ammonium persulfate-ammonium chloride-urea on curing and formic acid-ammonium chloride-urea system. It main use TG in Study the thermal decomposition process. the overcurrent ammonium-ammonium chloride thermal stability is the best,and formic acid-ammonium chloride, ammonium chloride system are followed.Thermal decomposition happen at190℃,so the curing temperature should be below190℃.