用二羟甲脲改性酚醛树脂制Ⅰ类胶合板的研究

通过用尿素和二羟甲脲改性酚醛树脂的对比试验,发现先将尿素和甲醛制成二羟甲脲后再加入酚醛树脂中参与合成,可增加尿素的用量,反应终点较易控制,树脂的贮存稳定性较好;苯酚与尿素的重量比为100∶75时,合成的二羟甲脲改性酚醛树脂用于压制胶合板,板的胶合强度仍达到国家标准GB9846 88中Ⅰ类胶合板的要求;最佳的热压工艺为:热压温度130℃、单位压力0 9MPa、热压时间0 9min/mm,固化条件比纯酚醛树脂低;由红外光谱分析可知,经二羟甲脲改性后形成了酚醛—脲醛共缩聚树脂;对原料成本概算,二羟甲脲改性的酚醛树脂比纯酚醛树脂降低了26%

Study on Type Ⅰ Plywood Using Phenol-formaldehyde Resin Modified by Dihydroxymethyl Urea

The comparison study shows that when urea and formaldehyde are prefabricated into dihydroxymethyl urea to modify phenol-formaldehyde resin, the usage of urea can be increased, the end point of reaction can be controlled more easily and the bin stability of resin is better in the course of modifying property of phenlol-formaldehyde resin by dihydroxymethyl urea than by urea. When the weight ratio of monophenol and urea is 100∶75,the plywood which is bonded with the phenlol-formaldehyde resin modified by dihydroxymethyl urea still reaches the request of type Ⅰ plywood about China National Standard GB9846-88. The optimum hot pressing parameters are respectively, hot pressing temperature 130 ℃, pressure 0.9 MPa, hot pressing time 0.9 min/mm thickness, it shows that solidifying condition of this kind of phenlol-formaldehyde resin is simpler and its material costs 26% less than the pure phenlol-formaldehyde resin. The analysis of Infrared spectrum shows that the phenolic-urea resin.was formed.