三聚氰胺共聚改性脲醛树脂固化性能研究

Study on curing properties of urea-formaldehyde resin modified by melamine copolymerization

采用M（三聚氰胺）对低n[F（甲醛）]∶n[U（尿素）]比例的UF（脲醛树脂）进行改性,制备了MUF（M共聚改性UF）;通过差示扫描量热（DSC）法表征了M的投料时间和比例对UF固化特性的影响,并对MUF的理化性能进行了评价。研究结果表明：随着M掺量的不断增加,MUF胶粘剂的固含量呈增长趋势,固化速率减慢,MUF中游离F含量显著降低。M投料时间对MUF的游离F含量、固含量和固化速率的影响不同,M在缩聚前期投料时,MUF的固含量较高,固化速率基本不变,游离F含量随M掺量增加而逐渐降低;当M在缩聚前期加入且w（M）=3%～4%（相对于U总质量而言）时,MUF中的羟甲基含量相对最低、MUF胶粘剂的综合性能相对最佳。

A MUF[M （melamine） copolymerization modified UF （urea- formaldehyde resin）] was prepared when the UF with lower n[formaldehyde （F）]： n[urea （U）] ratio was modified by M. The influences of M＇s feeding time and proportion on the UF＇ s curing characteristic were characterized by differential scanning calorimetry （DSC） method, and the MUF＇s physical and chemical properties were estimated. The research results showed that the solid content of MUF adhesive had the growth trend, curing rate was slower, and the free F content in MUF was obviously decreased with increasing M contents. The influences of M＇ s feeding time on the free F content, solid content and curing rate of MUF were different because the MUF had the higher solid content and basically unchanged curing rate, and its free F content was gradually decreased with increasing M contents when M was introduced into system at prophase of polycondensation. The MUF had the relatively minimum hydroxymethyl content, and the MUF adhesive had the relatively best combination property when M was introduced into system at prophase of polycondensation, and mass fraction of M was 3%-4% in U.