荧光增白剂的分散状态及其对PP白度的影响

Dispersion of Fluorescently Whitening Agent and Its Effect on Whiteness of PP

通过使用透射电子显微、相差显微和粒度分布分析,对荧光增白剂OB和OB1的形态及在PP中的微观状态进行了研究,并结合对PP增白样板白度的测定,找到荧光增白剂分散状态与试样白度的关系。结果表明:荧光增白剂OB和OB1在添加量为0.02%～0.03%时,其在PP中大部分是以粒径小于5μm的凝聚体形式存在的。此时荧光增白剂对PP有最佳的增白效果,可将试样白度提高5～7。添加量低于0.02%时增白效果不明显。添加量高于0.03%时,由于荧光增白剂与PP相容性的关系,凝聚体开始形成大尺寸团聚体,此时增白效果下降,甚至降低试样白度。荧光增白剂的热性能和结晶性能的测试也被用来辅助上述研究。研究表明:尽管两种荧光增白剂OB和OB1的热性能和结晶性能相差较大,但它们的分散状态及对其白度的影响是类似的。

The relationship between the whiteness of PP and the dispersion fluorescently whitening agent (FWA) in it was investigated through TEM, phase microscope and particle size analysis. The optimal loading range for FWA OB and OB-1 was 0.02 %～0.03 %, where they dispersed a small clusters less than 5 μm and provided excellent whitening. Below this range, the whitening was poor. Above this range, the FWA tended to aggregate to larger clusters, the whitening was also moderate. While OB and OB-1 possessed comparable whitening effects, their thermal and crystallizing behaviors were different.