The Study On The Application Of Waterborne Polyurethane Binder For Nonwoven Fabrics As Synthetic Leather

Synthetic leather produced by sea-island composite fibers has become the new developing trend in synthetic leather field and it shows great developing potentialities. This paper aims to do basic research contributing to the new environmental- friend synthetic leather process through using waterborne polyurethane as the binder.The paper mainly discussed the function and influence of some main factors on the process of synthetic leather. About the process, there are two process lines, which are "the back sea dissolution" and "the before sea dissolution".The results are as followed:During the "the back sea dissolution" process, (1) the rate of weight-loss an first becomes big rapidly and then increases slowly with the rate of sizing increasing; (2) the influence of the rate of sizing on synthetic leather's MD strength is not obvious, but its CD strength firstly becomes big and then reduces to some fixed value with the rate of sizing increasing; (3) the air permeability firstly becomes big and then gradually reduces with the rate of sizing increasing; (4) the bending rigidity becomes big with the rate of sizing increasing;(5) the rate of weight-loss reduces with PU content in synthetic leather increasing; (6) its tensile strength becomes big along with PU content in synthetic leather increasing; (7)its air permeability reduces with PU content in synthetic leather increasing; (8) its bending rigidity becomes big with PU content in synthetic leather increasing; (9) along with alkali concentration , alkali treating time, alkali treating temperature and bath ratio increasing, the rate of weight-loss will increase; (10) the tensile strength firstly reduces and then increases with alkali concentration, alkali treating time and bath ratio increasing; (11) the tensile strength gradually reduces with alkali treating temperature increasing; (12) along with alkali concentration , alkali treating time, alkali treating temperature and bath ratio increasing, its air permeability firstly gradually becomes big and then reduces; (13) along with alkali concentration , alkali treating time, alkali treating temperature and bath ratio increasing, its bending rigidity gradually reduces.During the "the before sea dissolution" process,(l)its rate of weight-loss keeps steady with the changing of the sizing rate; (2) the tensile strength rapidly becomes big and then reduces to a certain value with the rate of sizing increasing; (3) the air permeability decreases as the rate of sizing increasing; (4) the bending rigidity becomes big with the rate of sizing increasing; (5) the rate of weight-loss keeps steady with the changing of PU content in synthetic leather; (6) the tensile strength increases as PU content increasing; (7) the air permeability reduces as PU content increasing; (8) the bending rigidity increases as PU content increasing; (9) along with alkali concentration , alkali treating time, alkali treating temperature and bath ratio increasing, the rate of weight-loss gradually increases; (10) the tensile strength gradually reduces as alkali concentration increasing; (11) along with alkali treating time, alkali treating temperature and bath ratio increasing, the tensile strength firstly reduces and then increases; (12) along with alkali concentration , alkali treating time, alkali treating temperature and bath ratio increasing, the air permeability gradually reduces; (13) the bending rigidity gradually reduces along with alkali concentration, alkali treating time, alkali treating temperature and bath ratio increasing.At the present time, the most process of synthetic leather uses Polyurethane with DMF as binder. The problem is that the solvent DMF is poisonous so as to do harm on body and environment. As the synthetic leather technology developing, developed countries exploit a new environmental-friend synthetic leather technology, which is reinforced by waterborne polyurethane. The superiority of the technology lies in not only environmental-friend, but also its reinforced process is more simple and is more available for the industrialization development.