Polyurethane Synthetic Leather is a kind of polyurethane elastomer. It has soft gloss, nature, soft handle and strong dermis feeling. It has excellent mechanical properties such as excellent adhesion to base material, abrasion resistance, flexibility resistance and aging resistance. It also has good cold resistance, air permeability and washability. With the advantages of convenient processing and low price, it is the most ideal substitute for natural leather.

The industrial production methods of polyurethane synthetic leather are mainly dry and wet.

1. Dry polyurethane synthetic leather

Dry process usually takes release paper as carrier, scrapes polyurethane resin slurry onto release paper (usually scrapes one or two times), puts it into oven to heat and dry to remove solvent in resin, forms continuous and uniform polyurethane film, scrapes and coats the binder on the film, adheres to the cloth, after drying and curing, uses peeling package. The stripping paper is peeled off and the finished man-made leather and stripping paper are rolled separately. Polyurethane slurry coating agent, release paper and base cloth are three components of dry process. The synthetic leather produced by dry process has compact film layer, excellent product strength and firm bonding. The wastewater produced in the process is less, but the hygienic performance of the product is relatively poor, and the waste gas pollution caused by the production process is serious.

2 wet polyurethane synthetic leather

The wet process is mainly to squeeze the slurry into the space of the nonwoven fabric by extrusion, and then the non-woven fabric is put into the coagulation bath. The "DMF-H2O" system is mixed to make DMF continuously enter the coagulation bath from the resin solution. At the same time, the water enters the base cloth, so that PU gradually transforms from the dissolved state to the gel state, and finally forms the solid film. This is the case. In the process of exchange, due to the adjustment of additives and shrinkage of polyurethane, a large number of micro-holes will be formed, and a multi-layer structure with continuous porous layers can be obtained. Therefore, synthetic leather produced by wet method has good moisture permeability, air permeability, soft, plump and light feel, and is more rich in the style and appearance of natural leather.