Production method of polypropylene cooling masterbatch

Abstract

The invention discloses a production method of polypropylene cooling masterbatch, including the following steps: (1) mixing: the following components by parts by weight are mixed for 10-20 minutes: 50-90 parts of polypropylene resin, 0.5-9.5 parts of dispersing agent, 0.1-0.6 part of surface modifier, 0.1-2.7 parts of lubricant and 0.2-0.8 part of liquidity regulator, and then the following components by parts by weight are sequentially added: 0.1-0.9 part of light stabilizer, 0.1-1.6 parts of antioxidant and 0.2-7 parts of molecular weight regulator, and mixing is carried out for 5-15 minutes; (2) pelletizing: the mixed material is subject to melt extrusion at 130-230 DEG C and then grain-sized dicing is carried out. The invention adopts compound peroxide as molecular weight regulator and adopts compound antioxidant, compound dispersing agent, compound light stabilizer and compound lubricant, and the produced polypropylene cooling masterbatch has the advantages of high initiator content, good dispersity and obvious cooling effect and modification effect.

Description

technical field [0001] The invention relates to the deep processing of polypropylene, in particular to a production method of polypropylene cooling masterbatch. Background technique [0002] Polypropylene (PP) cooling masterbatch is made of polypropylene as the main raw material, adding molecular weight regulators, antioxidants, dispersants and other additives. obtained resin pellets. The use of cooling masterbatch in the processing of polypropylene resin can adjust the molecular weight of polypropylene, that is, adjust the melt index of polypropylene, and adjust the molecular weight distribution of polypropylene to make the molecular weight distribution of polypropylene narrower and increase the fluidity of polypropylene. Polypropylene cooling masterbatch is mainly used to reduce the processing temperature in the production of polypropylene spinning and plastic products, especially in the process of PP long and short filament spinning. At the same time, it is also widely ...

AI Technical Summary

Problems solved by technology

Due to the high relative molecular mass and wide relative molecular mass distribution of polypropylene, the melting temperature is high and the spinning forming temperature is high. Even when spinning short fibers at low speed, the spinning temperature is as high as 290°C, or even above 300°C. It is easy to decompose additives, pigments, etc., which brings many difficulties to the spinning process.

If the processing temperature is too high, it will not only waste electric energy, deteriorate the production and working environment, but also affect product quality, equipment life and production efficiency

The existing polypropylene with a low melt index (less than 30) is basically not suitable for high-speed spinning of fine-denier polypropylene filaments, so the development of polypropylene with a relatively low relative molecular mass and a relatively narrow relative molecular mass distribution has always been a research topic. hot spots

[0005] Although the existing cooling masterbatch prepared with polypropylene resin as a carrier and added with various functional additives has many advantages, it still has the following disadvantages in use: (1) it is difficult to dye the finished fiber; (2) it is resistant to optical rotation (3) High static electricity; (4) Poor flame resistance, which needs to be improved by adding various additives; (5) High requirements for raw materials for the production of polypropylene fibers, which require an isotacticity of 97% to 98%, Not less than 96%, the average molecular weight is 180,000-300,000, the crystallinity is above 65%, the thermal decomposition temperature is 350-380°C, the melting point is 158-176°C, etc.; It is polymerized, so it cannot produce secondary active centers, and only has a linear chain structure, which leads to its low melt strength and poor sag resistance; in the molten state, polypropylene has no strain hardening effect, and the additives in the existing formulation are for There are still deficiencies in improving strength and melting stability; (6) The softening point and melting point of polypropylene are close, and the melt strength drops rapidly after the temperature exceeds the melting point, resulting in uneven wall thickness of the product during thermoforming, extrusion, coating, calendering Edge curling, shrinkage, cell collapse during extrusion and foaming, etc.

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