Preparation and application of solvent-free spraying polyurethane pipeline mending coating

Abstract

The invention provides preparation and construction methods of a solvent-free spraying polyurethane pipeline mending coating, and a polyethylene (PE) heat shrinkable belt which is widely applied to the field of domestic 3PE pipeline mending at present can be replaced. The material is prepared from two components A and R; the component A is a quasi-prepolymer which is synthesized from 65-90 parts of isocyanate and 0-35 parts of polyether polyol; and the component R is prepared from 15-30 parts of a hydroxyl-terminated chain extender or cross-linking agent, 100-200 parts of oligomer polyol, 120-260 parts of filler, 2-8 parts of a water absorbent, 0.2-1.0 part of catalyst, 2-10 parts of an assistant and the like. The coating is free of solvent, free of environmental pollution and fast to cure, can achieve the appointed used thickness after being coated once, is anti-sagging, insensitive to the temperature and humidity, and excellent in ageing resistance and physical performance; and a tough anticorrosive protection layer is formed by rapid curing within half an hour after being coated on the 3PE pipeline interface by special equipment. The coating is mainly applied to on-site anti-corrosion mending of a 3PE pipeline, and also can be used for internal and external corrosion resistances of the pipeline.

Description

technical field [0001] The invention belongs to the technical field of polyurethane coatings, and in particular relates to the preparation and application of a solvent-free spraying type polyurethane pipeline joint coating. Background technique [0002] Three-layer polyethylene composite structure anti-corrosion coating (3PE) is a new type of pipeline anti-corrosion material that emerged rapidly in the world in the 1980s. With the wide application of 3PE, the sealing technology of 3PE anti-corrosion coating has also been developed. [0003] Almost all domestic 3PE anti-corrosion pipes are filled with polyethylene heat shrinkable tape. The difficulty in the construction of polyethylene heat shrinkable tape is mainly reflected in the fact that it is difficult to control the temperature during the baking process to meet the construction requirements, especially in the cold season when the temperature is low. It is difficult to guarantee the construction quality. In recent year...

AI Technical Summary

Problems solved by technology

The difficulty in the construction of polyethylene heat shrinkable tape is mainly reflected in the fact that it is difficult to control the temperature during the baking process to meet the construction requirements, especially in the cold season when the temperature is low. It is difficult to guarantee the construction quality

In recent years, the pipeline industry has invested a lot of manpower and material resources in the research and development of polyethylene heat-shrinkable tape jointing technology, especially the jointing construction tools, in order to reduce the influence of human factors on the quality of jointing in construction, but the effect of this effort not obvious

In practical application, quality problems were found during the installation and construction of the pipeline and when it was put into operation. Excavation inspections also found cases of joint failure, which constituted a potential threat to the safe operation of the pipeline.

In addition, the cost of overhauling the failed part of the joint is high. Taking the west line as an example, it costs an average of about 6,000 yuan per crossing in general areas, and tens of thousands of yuan per crossing in special areas such as water network areas.

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