Method for preparing special material for pipeline by crosslinking modifying of polyethylene

Abstract

The invention relates to a method for preparing a special material for a pipeline by crosslinking modifying of polyethylene. The method specifically comprises the following steps of mixing polyethylene particles, a polymerization inhibitor 701 and three types of antioxidants 1010, 412S and 697, adding into an extrusion machine, pumping a silane coupler VTMS and an initiator DCP into the extrusion machine in an atomizing and spraying way, extruding a melt, cooling, and cutting particles, so as to obtain a special material A for the pipeline; mixing the dried polyethylene particles and dibutyltin dilaurate, di-n-butyltin dilaurate and three types of antioxidants 1010, 412S and 697, feeding into the extrusion machine, extruding by the extrusion machine, cooling, and granulating, so as to obtain a special material B for the pipeline; mixing the material A and the material B according to a ratio, so as to prepare the special material for the pipeline. The method has the advantages that by adding the polymerization inhibitor, the pre-crosslinking of the polyethylene is avoided; by adding the silane coupler VTMS and the initiator DCP, the crosslinking degree and uniformity are improved, and the generation of gel blocks is avoided; by adding the three types of antioxidants as an anti-aging system, the anti-aging property of a product is improved, and the environment cracking-resistant ability of the pipeline is improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of polymer materials, and relates to a method for preparing special pipe materials through cross-linking modification of polyethylene (PE). Background technique [0002] Polyethylene (PE) is one of the main plastic raw materials in the five general-purpose plastics (PVC, PE, PS, PP, ABS), and is also the chemical product with the largest output of ethylene derivatives, accounting for about 50% of ethylene consumption. However, polyethylene has poor high temperature resistance, mechanical properties and anti-aging chemical properties can not meet the requirements of use, and cross-linked polyethylene has a unique molecular structure (three-dimensional network thermosetting structure) and excellent properties (such as high compressive strength) , high heat resistance, good corrosion resistance), just to make up for this gap, so its products have been widely used in floor heating, heating and coo...

AI Technical Summary

Problems solved by technology

[0004] The traditional cross-linked polyethylene used to prepare cross-linked polyethylene pipes is mainly made of silane cross-linked polyethylene. This cross-linked polyethylene is easy to absorb due to uneven dispersion of silane and initiator and special materials during storage and transportation. Moisture in the air produces pre-crosslinking phenomenon, which leads to the formation of gel blocks in the extruder, that is, vinyl silane is hydrolyzed to form silanol condensation polymers, and the degree of crosslinking of the obtained pipe pellets is reduced, and the crosslinking is uneven, and the mechanical properties Not good, need to use a lot of couplant; and the formed gel block needs to be cleaned regularly, and the corresponding equipment consumes a lot of energy. At the same time, many cross-linked polyethylene pipes on the market have leakage problems before their service life, especially for each connection. weak point