Preparation, Properties, Modification And Application Of Melamine Glyoxal Solution

Melamine formaldehyde resin (MF resin) is widely used in wet strength agent and woodadhesive because of high performance and low cost. But MF resin can constantly release freeformaldehyde which can endanger people’s health and quality of life. With development ofpeople’s living standard, MF resin has not satisfied the requirement of people on high standardenvironment. Therefore, a new type nontoxic-melamine product used in wet strength agentand wood adhesive became the direction of this research. The preparation, properties,modification and application in wet strength agent and wood adhesive of melamine glyoxalsolution (MG solution) had been researched.The mainly results are introduced as below:(1) Better synthesis conditions are shown as follows: m (glyoxal): m (melamine)=80/15,30methanol or ethanol as solvent, reaction temperature is60℃, without pH regulator.When water tolerance is2~3, it mean end point of reaction. The storage stability of MGsolution is more than30days.(2) MG solution was used as wet strength agent and wet strength of paper is above30MPa, wet strength retention rate is above50%. MG and its acrylic emulsion modified solutionwere used as wood adhesive, the shear tensile strength were all above2.5MPa beforeimmersed in water; after be immersed in water2hours, water resistance of MG solutionadhesive is poor, but the shear tensile strength of acrylic emulsion modified MG as adhesiveis above1.5MPa, strength retention rate is above50%. MG solution and its modificationwere used as plywood adhesive, the bond strength were between0.5MPa to1.7MPa.(3) Compared with IR spectra of melamine and MG solution, the infrared peak ofprimary amine of melamine disappeared and it means that some reactions happened whenmelamine added in glyoxal solution. The Liquid chromatography-Mass spectra was used toanalyze MG solution, molecular ion peaks of some possible structures in MG solution whichare soluble in methanol were proved by the mass spectrogram. The MG solution was dried forthermal analysis, DSC analysis shows that there is a sharp exothermic peak at160℃~170℃.And in the some temperature, TG-IR analysis shows that rate of weight loss is thefastest. TG-IR shows that there is a stable weight loss rate and carbon dioxide is released at200℃~800℃.(4) As to brittle of papers impregnated by pure MG solution, polyethylene glycol,caprolactam and acrylate emulsion were used as modifiers to improve toughness. At last, the conclusion was achieved that MG solution has potential to replace MF resinsolution used in wet strength agent and wood adhesives.