PE-RT (polyethylene of raised temperature resistance) composition and application thereof

Abstract

The invention relates to a PE-RT (polyethylene of raised temperature resistance) composition and application thereof, belonging to the field of polyethylene pipelines. The PE-RT composition is characterized by comprising the following components in parts by weight: 100 parts of PE-RT and 0.1-1.5 parts of antioxidant, wherein the PE-RT is an ethylene-hexene-1 copolymer which has a density of 0.926-0.950 g/cm<3>, a melt flow rate of 0.1-2 g/10min (190 DEG C, 2.16Kg of weights), unimodal molecular weight distribution and a relative branching degree of 0.08-0.50; and the antioxidant comprises a hindered phenol antioxidant and a phosphite antioxidant. According to the invention, the PE-RT composition having excellent mechanical properties, high-temperature creep resistance, heat aging resistance and extrusion processability is prepared from the heat-resistant ethylene-hexene copolymer, the antioxidant and other components, thereby further improving the practical performance of PE-RT pipe products. Thus, the PE-RT composition can be used for the preparation of pipe products and pipe fittings for a hot water pipeline system.

Description

technical field [0001] A heat-resistant polyethylene composition and its use, belonging to the field of polyethylene pipes, in particular to a heat-resistant polyethylene (abbreviated as PE-RT), antioxidants, etc., to prepare pipes with good heat resistance and long-term aging performance The polyethylene composition is used in the field of cold and hot water transportation, especially for pipes and pipe fittings for hot water transportation systems. Background technique [0002] PE-RT is a non-cross-linked polyethylene resin that can be used for hot water pipes. Early PE pipes can only be used in the field of cold water delivery. PE-RT is a copolymer of ethylene and octene, hexene or butene specially designed for cold and hot water supply pipes. It appears in the field of medium and high temperature water delivery. Brand new polyethylene pipe material. In recent years, PE-RT can replace random copolymer polypropylene (PPR), polybutene (PB), chlorinated poly Vinyl chlorid...

AI Technical Summary

Problems solved by technology

However, the patent does not mention the heat and oxygen aging resistance. For hot water pipes, the heat and oxygen aging resistance of the material is a very important indicator, which directly affects the service life of the pipe.

And for materials made by mixing several substances, due to the difference in material crystallinity, defects will occur at the phase interface of the blend, resulting in deterioration of the long-term performance of the material

[0004] Chinese patent application number 200710114113.4 "polyethylene resin composition for pipes and its preparation method" relates to thermoplastic pressure pipe and pipe fitting materials, the polyethylene resin composition has excellent short-term hydrostatic strength, resistance to slow crack growth and resistance to Rapid crack growth capability, the performance meets the requirements of PE100 grade pipe materials, and can be used to transport gas and cold water, but this invention cannot meet the heat resistance requirements of transporting hot water

However, according to the scheme disclosed in this invention, the polyethylene pipe obtained in the hydraulic test is 1000h at 95°C and a ring pressure of 3.5MPa. This data still has a lot of room for improvement on the basis of the scheme change.

In addition, the proposal does not disclose the type of antioxidant and the specific selected species, and the optimization of antioxidant is very important to the performance improvement of PE-RT, which directly affects the service life of the pipe, and does not disclose the oxidation-induced degradation of the obtained product. Performance in terms of period, tensile yield stress, etc.

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