Preparation Of Aqueous Polyurethane And Its Adhesion To Laminated Films

The self-emulsified polyurethane-polyacrylate anionomers were synthesized by prepolymer-dispersion-method. The materials included hydroxy ethylacrylate (HEA), MDI, poly(tetramethylene adipate)glycol(PBA), dimethylol propionic acid(DMPA), and various types of acrylate monomers.The emulsion particle size and storage stability were studied. Miscibility of polyurethane-polyacrylate blend and copolymer were compared. It was found that T-Style peel strength dropped when content of butyl acrylate increased. Moreover, the effect of various types of crosslinking agents on T-style peel strength was discussed.Aqueous polyurethanes whose solid content are 35% were also prepared. The materials consisted of MDI, poly(tetramethylene adipate)glycol(PBA, Mn=2000), polypropylene glycol)(PPG-400,1000), and dimethylol propionic acid (DMPA).The dispersions and its cast films were characterized. In addition, adhesion to PET/PE composite films was discussed.The test showed that dispersions had excellent storage stability while the content of -COOH was more than 0.87%. However, the water resistance was harmed if the content of -COOH was too high. The viscosity of aqueous PU was affected by the content of -COOH, neutralization degree, and temperature. Average particle size became smaller while neutralization degree of -COOH increased. Accumulation structure of PU was determined by thermal behavior curve (DSC). T-style peel strength dramatically increased as certain ratio of PPG-400 was incorporated. Furthermore, water resistance was improved. The effect of hard segments, ionic group, and PPG-400/PBA on hardness, breaking strength, and breaking elongation was also investigated.