Polyolefin filling masterbatch processing technology and related equipment have also changed with the continuous change of carrier resin.
The carrier resin used in the first generation polyolefin filling masterbatch (APP masterbatch) is domestic random polypropylene (actually the production of polypropylene by-products), the processing technology is: mixing-open mixing pull-water cooling pellet , For intermittent production, the equipment used includes an internal mixer, an open mixer, and a plate pelletizer.
The second generation polyolefin fillingmasterbatch is based on LDPE (1F7B) as the carrier resin, and the produced masterbatch is called PEP masterbatch. In this process, a single-screw extruder with a large length-to-diameter ratio and high mixing performance must be used in order to obtain good results.
Filling masterbatch with polypropylene powder as carrier, that is, PPM masterbatch is called my country's third generation fillingmasterbatch. Generally, the method of using polypropylene and polyethylene blend as the carrier resin will have a good effect. The product not only maintains the characteristics and use scope of the PPM masterbatch, but also adopts the die face hot air cooling process, which improves the production efficiency and reduces the raw material cost.
The best processing equipment for making fillingmasterbatch is co-rotating twin screw extruder. The machine has the advantages of continuous production, stable quality, high production efficiency, low energy consumption, low labor intensity of workers, and good operating environment.
Filling masterbatch contains fillers and auxiliaries in a large concentration. When using, a certain amount of matrix resin must be added to be mixed and then processed to form. The filler mainly plays a filling role. Fillers and additives can give plastic products special functions, such as: light, electricity, flame retardant, degradation, etc., called functional filler masterbatch. Functional masterbatch usually includes color masterbatch, light conversion masterbatch, high-efficiency thermal insulation film masterbatch, anti-fog drip masterbatch and degradation masterbatch.
Masterbatch is a kind of special granule for coloring plastic products. According to the variety of colored plastic, it can be divided into polyolefin, ABS, PS and AS. The production process of the color masterbatch is usually divided into two steps: the first step is to prepare the pigment pre-dispersion, that is, the surface treatment of the pigment with a dispersant or other additives; the second step is to mix the pigment pre-dispersion with the carrier resin The color masterbatch is prepared after melting granulation. The color masterbatch is composed of pigment, dispersant, carrier resin and appropriate amount of additives. The main function of the dispersant is to fully disperse the pigment and evenly disperse in the carrier resin and matrix resin, and finally obtain a plastic product with uniform color. The carrier resin used for the color masterbatch should first have good compatibility with the colored resin, and secondly the carrier resin should have greater fluidity than the colored resin so that the pigment can be better dispersed. The composition of the color masterbatch, the choice and amount of pigments depend on the nature of the colored plastic. The content of the pigment in the color masterbatch usually used for polyolefin plastic coloring is 20% to 40% (mass fraction).