聚氨酯中性施胶剂的制备及应用

Preparation and Application of Polyurethane Neutral Sizing Agent

在催化剂和少量助溶剂的作用下．以单硬脂酸甘油酯、异氟尔酮二异氰酸酯(IPDI)为原料合成了一种聚氨酯(PU)预聚体,以N-甲基二乙醇胺(MDEA)为亲水性扩链剂,通过HCl中和反应制备了一种新型的自乳化阳离子聚氨酯乳液。用FT-IR、激光粒径仪、X-射线衍射仪和纸张物理性能检测的手段对聚合物结构、乳胶粒子形态以及应用性能进行了表征,并研究了n(NCO)/n(OH)、扩链剂用量和中和程度对乳液稳定性和施胶性的影响。结果表明:n(NCO)/n(OH)=1．95～2．05,n(HCl)/n(MDEA)=1．0～1．2,MDEA用量为14%～16%,此时制得的阳离子聚氨酯乳液具有理想的乳液稳定性,胶乳颗粒较细,粒径分布也较窄,粒子尺寸＜1．320μm。聚氨酯乳液施胶剂提高了施胶度和纸张强度。

A kind of polyurethane （PU） pre-polymer was successfully prepared by using glycerine monostearte and isophorone diisocyante as raw material under the action of catalyst and co-solvent, then a new type of surfactant free cationic PU emulsion sizing agent was prepared with N-methyldiethanolamine as hydrophilic chain expender and via neutralization reaction. The chemical structure, particle morphology of the resultant dispersions and the physical properties of the sized paper were characterized with FT-IR, laser particle size analyzer, XRD and various paper testing equipments. The effects of the ratio of n （NCO）/n （OH）, the content of N-methyldiethanolamine and the degree of neutralization on the emulsion stability and sizing performance were studied. The results showed that when n（NCO）/n（OH）= 1.95-2.05, n（neutralize agent）/n（MDEA）= 1.0-1.2, MDEA dosage=14%-16%, the stability of the cationic PU emulsion is perfect, its particle size is fine, and particle size distribution is narrow （mostly less than 1.320 mm）. The sizing degree and paper strength are improved by PU emulsion sizing agent.