Sag resistant polypropylene and preparation method thereof

Abstract

The invention relates to sag resistant polypropylene and a preparation method thereof, wherein the raw materials thereof are as follows in parts by weight: 100 parts of linear polypropylene, 0.5-5 parts of compatilizer, 1-5 parts of nano-clay and 0.5-1 part of antioxidant; and the product is obtained by extruding the raw materials in an extruder at the temperature of 175-205 DEG C. The preparation method comprises the following steps: mixing the linear polypropylene and compatilizer; adding the nano-clay and antioxidant, mixing to obtain a mixed material; adding the mixed material in a dual-screw extruder; extruding and pelletizing at the temperature of 175-205 DEG C; and drying. The invention intercalates the polymer large-molecular chain between sheets of a stack structure of the nano-clay so as to generate a polypropylene / nano-clay composite material with an intercalated structure, and the intercalated stack structure assembly services as a physical linking point in the polypropylene melt, thus improving elasticity of the polypropylene melt, and enhancing the slag-resistance performance of the polypropylene melt.

Description

technical field [0001] The invention relates to a polypropylene polymer material and a preparation method thereof, in particular to a polypropylene with high sag resistance and a preparation method thereof, belonging to the field of polymer material synthesis. Background technique [0002] Sag resistance is the ability of a polymer melt to bear its own weight. It is a rheological property of a material and is usually measured in a molten state. General-purpose polypropylene is a linear polymer, its viscosity drops sharply after the melting point, and it does not exhibit "strain hardening" characteristics. The melt has poor sag resistance, resulting in uneven product wall thickness during thermoforming; extrusion coating , Edge curling and shrinkage during calendering; cell rupture and collapse during extrusion foaming, these problems limit the application of polypropylene in the fields of thermoforming, extrusion coating, extrusion foaming and blow molding application. [...

AI Technical Summary

Problems solved by technology

[0004] Among the above-mentioned modification methods, the long-chain branching technology requires irradiation equipment, and the process is complicated, resulting in high modification costs, and the price of the obtained long-chain branched polypropylene is almost twice that of linear polypropylene. , and it is difficult to control the appearance of reaction by-products such as gels and oligomers during the irradiation process. In fact, what is obtained is a mixture of various products, which can easily damage the physical and mechanical properties of the material while improving the anti-sag performance; In the blending modification method, the improvement of anti-sagging performance benefits from the addition of other polymer materials, and the addition of a high amount can make the anti-sagging performance of polypropylene reach a satisfactory level, while high content of The addition of heterogeneous polymer materials can also negatively affect the physical and mechanical properties of polypropylene

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