Preparation method of beta crystal polypropylene/PET (Polyester) alloy

Abstract

The invention belongs to the field of chemical engineering, in particular to a preparation method of a beta crystal polypropylene / PET (Polyester) alloy, which comprises the following steps: mixing beta crystal polypropylene, PET (new material or recovering material) and a compatilizer and carrying out melt extrusion; or mixing a beta crystal nucleating agent, polypropylene, PET (new material or recovering material) and a compatilizer and carrying out melt extrusion. The adopted compatilizer is one or more of ethylene-octene copolymer grafted maleic anhydride, ethylene-vinyl acetate copolymer grafted maleic anhydride, polypropylene grafted maleic anhydride or polypropylene grafted glycidyl methacrylate. By introducing the compatilizer in a certain proportioning range, the crystallization of the PET can be blocked through the chemical reaction and the polarity action of the compatilizer and the PET, so that the nucleating capability of alpha crystal of the PET is reduced, the nucleatingefficiency of beta crystal of the beta crystal nucleating agent is easily improved and the high-content beta crystal polypropylene / PET alloy can be formed; and meanwhile, the invention solves the problems of thermodynamic compatibility of the polypropylene and the PET, the yield strength and low modulus.

Description

technical field [0001] The invention belongs to the field of chemical industry, and relates to a preparation method of a polymer alloy material, in particular to a preparation method of a polypropylene / PET alloy with high β crystal content. Background technique [0002] Polypropylene has a variety of crystal forms, namely α, β, γ, δ and pseudo-hexagonal crystal. Among them, the α crystal form is the most common, and β crystal polypropylene is a new type of polypropylene. In addition to the good comprehensive properties of α crystal polypropylene, compared with α crystal polypropylene, β crystal polypropylene has better impact strength and heat resistance. The deformation temperature is greatly increased, showing higher toughness and ductility under high-speed stretching. [0003] The formation of β-crystalline polypropylene mainly includes three methods: temperature method, shear orientation method and adding nucleating agent. Among them, adding β-crystalline nucleating age...

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Problems solved by technology

[0005] The existing method of preparing β-crystalline polypropylene alloy is to adopt a blending method, but the thermodynamic instability of β-crystalline polypropylene, the β-crystalline content of polypropylene in the alloy is affected by the addition of the second component, so that the content of β-crystalline polypropylene in polypropylene significantly reduced or even disappeared. Taking the preparation of polypropylene / PET alloy as an example, when polypropylene and PET are melted and blended at high temperature, due to the polarity of the β-crystal nucleating agent and PET, in the preparation of β-crystal polypropylene / PET alloy During the process, the nucleating agent will migrate to the PET phase or the two-phase interface, which will reduce the β-nucleation effect of the nucleating agent on polypropylene, thereby reducing or even disappearing the content of β-crystalline polypropylene in the alloy.

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