Developing Embossed Release Paper For PU Artificial Leather Production

On the basis of comparison of the fore results of researching, this paper puts forward a method of manufacturing a kind of release paper for PU artificial leather production first in China. Which is extrusion coated a mixture of polypropylene and polyethylene on a kind of base papsr, and then embossed, and it is succeeded in practice. The properties of the release paper, such as strength, heat resistance, release force, unification of pattern and glossy, etc, are all met the demands, its re-using times of the release paper is up to more than 50 times.The requests of raw materials, such as base paper, polypropylene, polyethylene, etc, are studied by experiments. The base paper is made of bleached sulphate wood pulp, neutral or near neutral sized, and with low filler or free of filler. Its base weight is 110~140g/m~2. The suitable MFR of polypropylene is 6-12 g/10min, and the suitable MFR of polyethylene is 1~10 g/10min.The parameters, which includes the rate of polypropylene and polyethylene, temperature curve of extrusion, coating pressure, surface temperatures of paper and engraved roll, embossing pressure, etc, are studied by experiments, In order to get a good adhesive strength of coat layer and base paper, the rate of polyethylene should be more than 20%, but the heat resistance and re-using times would drop in excess. Using a co-extruder with two extruders and one T-die, instead of a single extruder, can solve this problem. The temperature curve of the resins in extrusion should be controlled in a reasonable range. It is the best manner that the paper should be embossed at the same time when it is extrusion coated to avoid some bad factors such as bubbling in the coat layer when it is heated up again. The surface temperature of coated paper is between 180-200℃, the surface temperature of engraved roll is between 50~105℃, and the embossing pressure is between 15~25kg/cm in embossing process.The result shows that it is feasible that the release paper for PU leather production can be manufacture with above process in economic and technologic aspects. It is significative and lays a foundation for making all kinds of release paper used in artificial leather manufacturing process in our country that embossed release paper for PU artificial leather production is successfully trial-produced.