On the basis of original refrigeration system of imported Japanese MLEA 65/1200 extrusion coating machine and according to the characteristic of the cold climate of northern area, a new set of energy saving refigeration ststem was designed and its working principle and energy saving effect were explained The structure of the new set is simple, and the design is distinctive It works reliably and beneficiably and is worth spreading in cold northern area
However, due to its linear chain structure and appropinquity of softening point and melting point, its melt strength and melt viscosity harshly drops with the temperature rising beyond its melting point, which results in the difficulties in thermoforming, extrusion coating, and extrusion foaming.
High melt strength grade of PP(HMSPP) is designed and commercialized to overcome the resin's melt-strength weakness and to withstand higher mechanical stress. HMSPP permits melt-phase thermoforming, extrusion coating and foam sheet extrusion on conventional equipment. There fore, the application scopes of PP are expanded.
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.
The development of techniques for pipeline cleaning and repairing is introduced. The technology of chemical cleaning and the properties of extrusion coating repairing materials were studied. High build paint has been applied to corrosion protection of high pressure water injection pipeline.
This paper presents the key technology of LDPE extrusion coating. It includes the selection of the LDPE resin and the controlling method of adhesive ability, heat seal-ability and transparency of the laminative product.