Preparation Of Crosslinked Aqueous Polyurethane And Its Application

The self-emulsified polyurethane-polyacrylate anionomers were synthesized byprepolymer-dispersion-method. The materials included TDI, polyester diol (polyetherdiol), dimethylol propionic acid (DMPA),trithylamine(TEA).The emulsion particlesize and storage stability were studied. The effect of hard segments on hardness,breaking strength and breaking elongation was also investigated. The effect ofdifferent materials,the content of carboxyl and NCO/OH on T-style peel strength wastalked .It was found that dispersions had excellent storage stability while the contentof –COOH was more than 0.80%. The viscosity of aqueous PU was also effected bythe content of –COOH, T-style peel strength was effected dramatically by the differentmaterials. T-style peel strength was also changed by the content of carboxyl orNCO/OH. Moreover, the effect of various types of crosslinking agents on T-style peelstrength was discussed. It was found that T-Style peel strength increased largerest ascertain ratio of polyisocyanntes was used. The effect of heat treatment on T-style peelstrength was obvious.Another aqueous polyurethane was also prepared. The materials consisted ofTDI,polyester diol,dimethylol propionic acid(DMPA),crosslinking agents(Ca,TMP).The synthesize technics, the dispersions and its cast films were characterized. Inaddition, adhesion to PET/PE composite films was discussed.It showed that the synthesize technics was hard to control if TMP was chose,butit was easy if Ca was used. The test showed that the water resistance and T-style peelstrength was good whichever TMP or Ca was chose. The effect of Ca on T-style peelstrength was larger than TMP's. T-style peel strength was best (4.42N/15mm)whenthe content of Ca got 0.06mmlo/g. The destroying types was inside destroying.Transmission of spectrum showed Ca had effective reaction with excessive –NCO. ⅢAccumulation structure of PU was determined by Dynamic Mechanical Analysis(DMA). The test showed the films' Storage Modulus Loss Modulus and Tg of the differentcontent of hard segment is different.Furthermore, the films' Storage Modulus and LossModulus increased as crosslinking agent was used. But the effect of crosslinking on Tg wascomplex.