单组分封闭型聚氨酯胶黏剂的制备及性能研究

Study on preparation and property of one-component closed polyurethane adhesive

以二苯基甲烷二异氰酸酯(MDI)和聚己二酸-1,4-丁二醇酯二醇(PBA)为主要原料合成预聚体,然后使用甲乙酮肟(MEKO)封闭异氰酸酯得到封闭型聚氨酯,将封闭型聚氨酯与低相对分子质量聚酰胺(LMPA)混合制备了单组分封闭型聚氨酯胶黏剂。采用傅里叶变换红外光谱仪和差示扫描量热法研究了封闭型聚氨酯的解封温度和胶黏剂的扩链反应,并讨论了异氰酸酯(—NCO)基团含量、扩链系数、湿固化时间和硅烷偶联剂γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)含量对胶黏剂拉伸剪切强度的影响。结果表明:封闭型聚氨酯150℃能够解封,当NCO质量分数为4.79%,扩链系数为0.9,湿固化时间为7d,KH560质量分数为2%时,胶黏剂的拉伸剪切强度最大为7.13MPa。

Firstly,diphenylmethane diisocyanate(MDI)and poly 1,4-butanediol adipate diol(PBA)were used as main raw materials to synthesize prepolymer(PUR),then methyl ethyl ketone oxime(MEKO)was used to block isocyanate to prepare PUR sealant,and then one-component blocked PUR adhesive was prepared from blocked PUR and low molecular polyamide(LMPA).The unsealing temperature and the chain extension reaction of the adhesive were studied by Fourier transform infrared spectroscopy and differential scanning calorimetry(DSC).The effects of mass fraction of isocyanate group(—NCO)content of PUR,chain extension coefficient,post-curing time andγ-glycidyl ether oxypropyl trimethoxysilane(KH560)content on the tensile shear strength of the adhesive were discussed.The results shown that the sealant can be unsealed at 150℃.When NCO content was 4.79 wt%,chain extension coefficient was0.9,wet curing time was 7 days,KH560 content was 2 wt%,the maximum tensile shear strength of the adhesive was7.13 MPa.