Method for preparing plastic formwork from waste polypropylene granules through modification

Abstract

The invention discloses a method for preparing a plastic formwork from waste polypropylene granules through modification. The method comprises the steps that 85-90 parts of waste polypropylene granules and 10-15 parts of modified master batch are taken and evenly stirred to be added into a reaction type extruder, molten modified polypropylene is generated through a grafting reaction, and extrude shaping, cooling and traction in a plate mold are carried out; finally, length cutting is carried out, and the high-strength polypropylene composite plastic formwork is obtained. The method is simple in technological process and free of environmental pollution, and the prepared polypropylene composite plastic formwork is light, resistant to heat and shock, good in nailing performance and low in price.

Description

technical field [0001] The invention relates to the field of polymer material modification, in particular to a method for making plastic templates by modifying waste polypropylene particles. Background technique [0002] Polypropylene (hereinafter referred to as PP) has a wide market demand for its excellent heat resistance and mechanical properties, but PP is a crystalline polymer, its softening point and melting point are very close, and its melting range is narrow; when the temperature is higher than the crystalline melting point When thermoforming, the strength drops sharply, resulting in the viscoelastic region of PP not being stable in a wide temperature range during thermoforming, the melt strength of PP drops rapidly, and its viscosity will also decrease rapidly. The PP melt film is difficult to form. The melt index of waste polypropylene is higher and the melt strength is lower, especially when the waste polypropylene is processed into thin-walled products of 0.5-2...

AI Technical Summary

Problems solved by technology

[0003] Waste and old multi-layer composite flexible packaging films such as PET / polypropylene, PET / polyethylene and PA / plastic composite materials (washing powder bags, express packaging bags, electric component bags, etc.) are non-polar materials and cannot be used in common with PP and PE Resin compatibility, usually using hot melt adhesive to bond them together to form a multi-layer composite flexible packaging film, but landfill, incineration, degradation and the reduction of waste plastics to petroleum will cause secondary pollution

Conventional production of PP / PA plastic templates is obtained by adding POE graft compatibilizers. Generally, the price of graft compatibilizers is relatively expensive, and the addition amount of 15-20% is equivalent to the price of waste composite plastics, so there is no commercial value. , and the effect is not very good, the cost of adding grafted POE is greatly increased, and at the same time, the rigidity and heat-resistant temperature are greatly reduced, and it is impossible to make plastic building templates with heat-resistant requirements.

[0004] Therefore, the use of polypropylene particles to make conformable plastic templates needs to solve the two major problems of composite plastic compatibility and increase melt strength. Melt grafting of polypropylene to produce polar functional groups and branched chain structures is the key to solving the compatibility of composite plastics. And the best way to improve the melt, but the melt grafting reaction requires anhydrous conditions, and the drying conditions of waste plastic particles can not reach the water content (about 0.1‰) required for the grafting reaction, it is necessary to find another method

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