A kind of polypropylene resin specially used for high-speed biaxially stretched film and its preparation method and application

Abstract

The invention discloses a polypropylene resin specially used for high-speed biaxially stretched films and its preparation method and application. The polypropylene resin includes the following components in parts by mass: 100 parts of polypropylene powder, 0.02-0.1 parts of main antioxidant Agent 1010, 0.02-0.1 part of auxiliary antioxidant 626, 0.015-0.05 part of acid-absorbing agent hydrotalcite; its preparation method includes the steps of: preparing polypropylene powder by polymerization in a fully mixed Unipol gas-phase fluidized reactor; The main antioxidant 1010, the auxiliary antioxidant 626 and the acid absorbing agent hydrotalcite are respectively added to the propylene powder, and a twin-screw extruder is used to melt, extrude and pelletize to obtain pelletized polypropylene resin. The homopolypropylene prepared by the present invention has a medium to wide molecular weight distribution, a suitable isotactic index, good tensile strength and stiffness, high processing stability, good thermal oxidation resistance, low membrane rupture rate, and yellowness index. Lower, better transparency.

Description

technical field [0001] The invention belongs to the technical field of olefin polymerization, and in particular relates to a polypropylene resin specially used for high-speed biaxially stretched films and its preparation method and application. Background technique [0002] Biaxially oriented polypropylene (BOPP) film is one of the fastest growing varieties of polypropylene processed products in recent years, because it is colorless, odorless, tasteless, non-toxic, and has high tensile strength, high rigidity and good Transparency is widely used in the field of packaging materials. Biaxially oriented polypropylene film has a wide range of uses. It is usually made of polypropylene resin as a raw material. After being extruded into a film, it is manufactured through a series of processes such as biaxial stretching, heat treatment, and cooling treatment. [0003] The processing and use performance of BOPP film depends on its melting characteristics, optical properties and mech...

AI Technical Summary

Problems solved by technology

For example, Chinese patent CN101058654 discloses a preparation method of a high-performance polypropylene composition. Asymmetric hydrogenation and asymmetric addition of an external electron donor (ring tube + ring tube) are polymerized step by step to prepare polypropylene with a wide molecular weight distribution. The obtained polypropylene Propylene has the characteristics of high isotacticity in low molecular weight fractions and low isotacticity in high molecular weight fractions. In addition, the asymmetric hydrogenation step polymerization operation is complicated, and product performance indicators such as melt index fluctuate greatly, which is not conducive to the high-speed production of BOPP films.

[0005] In addition, the traditional stabilizer system used in BOPP special materials is tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, tris(2,4-di-tert-butyl Phenyl) phosphite and calcium stearate are used in combination. This additive formula can basically guarantee the processing stability of BOPP special materials. However, for the production process of high-speed BOPP films greater than 300m / min, the resin The thermo-oxidative aging is serious, it is difficult to maintain a stable melt flow index and isotacticity, the film is easy to break during the production process, and the film color is easy to turn yellow, and calcium stearate is easy to precipitate, resulting in crystal points and filter screen replacement Problems such as short cycle times affect the appearance of the film and production efficiency, etc.

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