Silicane crosslinked high density polyethylene composition and its preparing method

Abstract

The present invention discloses silicane crosslinked high density polyethylene composition and its preparation process. The polyethylene composition is prepared through two-step silicane crosslinking process, and may be used in the production of crosslinked polyethylene pipe, crosslinked composite polyethylene-aluminum pipe, etc. One compounded crosslinking agent and one compound polymerization inhibitor are used to prevent too fast crosslinking and prolong the storage period, HDPE is used to raise the strength of the material, and proper carrier resin is selected to decrease the loss of silicane and other liquid assistants, so as to obtain the silicane crosslinked polyethylene composition, which may be used in producing composite plastic-aluminum pipe and crosslinked polyethylene pipe with high machining adaptability and excellent product performance.

Description

Technical field [0001] The invention relates to a cross-linked polyethylene composition and a preparation method thereof, and belongs to the technical field of polymer compositions. The invention adopts a two-step silane cross-linking technology to prepare a polyethylene composition, which is used for the production of cross-linked polyethylene pipes, cross-linked polyethylene aluminum-plastic composite pipes and the like. Background technique [0002] Traditionally, metal pipes are used for water supply pipes (including hot water pipes), drain pipes, gas pipes, etc. At present, a variety of plastic pipes including cross-linked polyethylene pipes are more and more widely used in the above fields. There are three methods for industrial production of cross-linked polyethylene, namely radiation cross-linking, peroxide cross-linking and silane cross-linking. Because radiation cross-linking equipment is expensive, its application is greatly restricted, and peroxide cross-linking is di...

AI Technical Summary

Problems solved by technology

[0005] First, the storage time of the grafting material is short: because the silane on the grafting is easy to react with the water in the air to produce pre-crosslinking, which affects the production of pipe molding, which determines its short storage period (usually 6 month or so), which brings great difficulty and inconvenience to enterprises in arranging production

[0006] Second, the crosslinking is uneven and the cost is high: CN 1195673A discloses a two-step method for preparing silane crosslinked polyethylene aluminum-plastic composite material and its preparation method

In addition, in the process of grafting and granulation, silane inevitably comes into contact with the hopper, barrel and screw of the extruder, resulting in the loss of silane crosslinking agent and reducing the utilization rate of expensive silane crosslinking agent. In addition, silane crosslinking agent The loss of agent is random, which can easily cause uneven crosslinking

[0007] Third, the strength of the composition and the prepared pipe is low, and it is difficult to meet the performance requirements of the product: in silane crosslinked polyethylene (including low-density polyethylene LDPE, linear low-density polyethylene LLDPE and high-density polyethylene HDPE), in In the case of achieving the same grafting rate, high-density polyethylene is relatively difficult, and its processing after grafting is also relatively difficult, which may easily cause poor appearance quality of the product. Therefore, LDPE and LLDPE compositions are currently used to prepare silane crosslinked polyethylene. Pipes, which have low strength and pressure resistance