防潮纤维板用三聚氰胺改性低物质的量比脲醛树脂胶粘剂研究

Study on low mole ratio urea-formaldehyde resin adhesive modified by melamine for moisture-proof fiberboard

低物质的量比脲醛树脂胶粘剂制备的纤维板的力学性能及防潮性能低,因此通过脲醛树脂的改性处理对提高纤维板的性能具有重要意义。以三聚氰胺为改性剂,采用一次性加入的方式制备三聚氰胺改性低物质的量比脲醛树脂。探究了不同三聚氰胺用量对脲醛树脂及其制备的纤维板理化性能的影响。研究结果表明:当三聚氰胺质量分数从0增加到25%,改性脲醛树脂的贮存稳定性较好,固化时间先延长后缩短,游离甲醛释放量先降低后增加但均处于E1级以下;三聚氰胺的加入显著提高了脲醛树脂的胶接性能及耐水性能,三聚氰胺用量达到25%时,纤维板的吸水厚度膨胀率可以从12.73%降低至3.69%;三聚氰胺的加入封闭了亲水性基团,降低了脲醛树脂固化后的结晶度,提高了纤维板的力学性能和防潮性能。

The mechanical and moisture-proof properties of fiberboard prepared with low mole ratio urea-formaldehyde resin adhesive are low,therefore it is of great significance to improve the performance of fiberboard by modifying urea-formaldehyde resin.Using melamine as the modifier,the low mole ratio urea-formaldehyde resin modified with melamine was prepared by one-time addition method.The effects of different contents of melamine on the physical and chemical properties of urea-formaldehyde resin and its prepared fiberboard were investigated.The research results showed that when the mass fraction of melamine increased from O to 25%,the storage stability of the modified urea-formaldehyde resin was good,the curing time was first extended and then shortened,and the release of free formaldehyde was first reduced and then increased,but all were below E1 level.The addition of melamine significantly improved the bonding performance and water resistance of urea-formaldehyde resin.When the content of melamine reached 25%,the thickness swelling rate of the fiberboard could be reduced from 12.73%to 3.69%.The addition of melamine blocked the hydrophilic groups,reduced the crystallinity of the cured urea-formaldehyde resin,and improved the mechanical and moisture resistance of the fiberboard.