A kind of pipeline no-solvent polyurethane preventing corrosion of repaired mouth coating
Technical field
The present invention is a kind of metallic conduit no-solvent polyurethane preventing corrosion of repaired mouth coating, relates to general corrosion protection and the tubing system technical field of metallic substance.
Background technology
Current oil and gas pipeline Heavenly Stems and Earthly Branches line preservative coat major part adopts 3 layers of PE preservative coat, and in existing various opening-supplementing material, the base type being applicable to 3PE corrosion-proof pipe line repaired mouth comprises following 4 kinds: (1) thermal polycondensation ethene anticorrosive products; (2) double component solvent-free epoxy coating; (3) double component solvent-free polyurethane coating; (4) coldly the anticorrosion tape wrap with heat is twined.
For the misgivings to result of use, limit by factors such as product technology and working equipment conditions, at present on main line 3 layers of PE corrosion-resistanting interpolating port still based on thermal polycondensation vinyl material.Liquid coating repaired mouth is a kind of more recent technology, mainly contains liquid epoxy and urethane two kinds, compared with radiant crosslinked polyethylene heat shrinkable goods repaired mouth; there is coating process simple, high with steel interfacial adhesion strength, repair easily; assay is reliable, does not have the advantages such as cathodic protection current shielding.
Compared with epoxy liquid coating, polyurethane liquid coating repaired mouth has two large advantages: one is that curing speed is fast, when especially temperature is lower still can normally, fast setting, the repaired mouth activity duration can be reduced; Two is very easily by regulating the structure of components and isocyanic ester in urethane repaired mouth coating, can obtain preferably balance quality, thus urethane repaired mouth coating shortcoming that epoxy liquid repaired mouth coating flexibility, shock-resistance can be avoided poor.
Existing urethane repaired mouth coating, the component A be usually made up of hydroxyl component, filler, functional aid etc., and form containing the B component of isocyanic ester.Hydroxyl component multiselect is with based on propylene oxide, and by anionic ring-opening polymerization, and the polyoxypropylene polyol of two functionality obtained or three-functionality-degree and their compound form.Patent CN1089965A describes a kind of double-component polyurethane coating being applicable to anti-corrosion of metal, wherein, polyethers component by two functionality, the polyoxypropylene polyol of hydroxyl equivalent between 500-2000; And three-functionality-degree, the polyoxypropylene polyol of hydroxyl equivalent between 100-200 is composite to be formed.
But based on anionic ring-opening polymerization, the polyoxypropylene polyol obtained, its terminal hydroxy group is secondary hydroxyl.This can produce following problem:
(1) the B component isocyanic ester in anti-corrosion polyurethane coating, is easy to react with the moisture in residual minor amount of water in component A or air, produces bubble, thus affect the performance of coating.In order to address this problem, usually need to carry out deep dehydration to component A, and adding a large amount of water-retaining agent, select the methods such as dry weather construction, reduce coating bubbles problem.
(2) reactivity ratio's primary hydroxyl of secondary hydroxyl and the reactive behavior of isocyanate component low, thus, quick-setting effect be reached, need to add the promotion secondary hydroxyl of significant proportion and the curing catalyst of isocyanate reaction.
In addition, in order to be applicable to the needs of pipeline cathode protection, urethane repaired mouth coating also needs to have good antikathode stripping ability.Compared with epoxy repaired mouth coating, in the film forming matter after urethane repaired mouth paint solidification, not hydroxyl.Thus, adopt current polyoxypropylene polyol, the antikathode stripping ability of urethane repaired mouth coating is difficult to reach the level suitable with epoxy repaired mouth coating.
Summary of the invention
The object of the invention is invention a kind of for buried pipeline corrosion protection coating repaired mouth, overhaul water-absorbent is little, reactive behavior is high, film forming matter has excellent antikathode stripping performance and the two-pack polyurethane preservative coating of heat-proof water adhesion performance.
Anti-corrosion polyurethane coating of the present invention is made up of component A and B component, and wherein component A comprises components, dispersion agent, defoamer, water-removal agent, anti-settling agent, coupling agent, curing catalyst, rust-stabilising pigment, titanium dioxide, mica powder, barium sulfate; B component is polyisocyanates.
The proportioning of component A is: in weight 100%, and components accounts for 35-45%, dispersion agent accounts for 0.3-0.5%, defoamer accounts for 0.5-1.0%, water-removal agent accounts for 3-7%, anti-settling agent accounts for 0.5-1.0%, coupling agent accounts for 0.5-1.0, curing catalyst accounts for 0.5-1.0, rust-stabilising pigment 10-15%, titanium dioxide account for 8-10%, mica powder accounts for 10-15%, barium sulfate accounts for 15-20%.The weight ratio of component A and B component is 100: 24-100: 29.
Described components is take dihydroxyphenyl propane as initiator, there is the extraordinary polyvalent alcohol of polymer with bis phenol A oxyethane and their compound of following molecular structure, wherein, a and b is the integer between identical or different 1-20, and the average equivalent of the extraordinary polyvalent alcohol of described polymer with bis phenol A oxyethane is 200-2000;
Described mica powder particle diameter is 600-800 order sheet powder, plays and strengthens the effect of coating osmotic-pressure-tolerant;
Described coupling agent is organo silane coupling agent, plays the effect strengthening and be coated with sticking power;
Described rust-stabilising pigment is zinc phosphate;
Described polyisocyanates is the polymeric MDI obtained by commercialization approach, or the MDI of Carbodiimide-Modified, and their compound;
The extraordinary polyvalent alcohol of described polymer with bis phenol A oxyethane, compared with polyoxypropylene polyol, due to the existence of phenyl ring in structure of bisphenol A in the middle of molecular chain, thus has good hydrophobic performance; Simultaneously ethylene oxide-capped possessed primary hydroxyl structure, its reactive behavior far above polyoxypropylene polyol with secondary hydroxyl, and the reactive behavior of primary hydroxyl and isocyanic ester is higher than the reactive behavior of water and isocyanic ester.Thus, the component A containing the extraordinary polyvalent alcohol of polymer with bis phenol A oxyethane of the present invention, not easily absorbs water in production process and construction process; Secondly, highly active primary hydroxyl can be competed with trace water and be reacted, and significantly reduces the reaction probabilities of isocyanic ester and trace water, further reduces the generation of coating foaming phenomenon; In addition, when highly active primary hydroxyl decreases and meets coating fast setting, to the consumption requirement of curing catalyst.
The extraordinary polyvalent alcohol of polymer with bis phenol A oxyethane used in the present invention, has the structure of bisphenol A identical with bisphenol A type epoxy resin in molecular chain structure.Structure of bisphenol A can give anti-corrosion polyurethane coating film forming matter preferably antikathode stripping ability and heat-proof water adhesion performance.
This formula is as buried pipeline three-decker polyethylene anticorrosive coating (3LPE) repaired mouth coating, 10Mpa is greater than to method of the pulling open sticking power of steel substrate, before coating prefabrication coating 3LPE preservative coat, corresponding first 3LPE carries out coarsen treatment, can sandblasting, also by the mode of flame plucking, then PE can be heated to 80 DEG C, spray or brush this coating.In addition another feature of this coating is have good resistance to cathodic disbonding performance, and property indices meets the requirement of " buried pipeline external anti-corrosion layer patch technology specification " ISO21809-3, in table 1:
Table 1 liquid polyurethane paint coatings performance index
The invention provides a kind of dual-component polyurethane corrosion-resistanting interpolating port coating being applied to joint coating on pipeline, this coating is cleverly by the selection of component A middle-end oxy-compound, decrease coating bubbles problem, decrease catalyst levels, reduce the requirement to coating producing process and execution conditions, and coating have good resistance to cathodic disbonding performance and heat-proof water adhesion performance.Because this coating property is excellent, produce in addition and convenient construction, will be widely used in joint coating on pipeline field.
Embodiment
Embodiment 1. examples are made up of component A and B component.The proportioning of component A is: in weight 100%, average equivalent be 240 polyvalent alcohol account for 24%, average equivalent be 800 polyvalent alcohol accounts for 16%, dispersion agent accounts for 0.5%, defoamer accounts for 0.5%, water-removal agent accounts for 5%, dust-proofing agent accounts for 0.5%, coupling agent accounts for 0.5%, Ammonia promotor accounts for 0.8%, rust-stabilising pigment zinc phosphate accounts for 15%, titanium dioxide accounts for 8%, mica powder accounts for 11%, barium sulfate accounts for 18.2%;
The solidifying agent (Bayer DesmodurVL solidifying agent) of B component accounts for 25% of component A gross weight.
The properties test result of material is as following table 2:
Table 2 unmaned platform the performance test results
Embodiment 2. examples are made up of component A and B component.
Component A proportioning be in weight 100%, average equivalent be 300 polyvalent alcohol account for 30%, average equivalent be 1200 polyvalent alcohol accounts for 12%, dispersion agent accounts for 0.3%, defoamer accounts for 0.8%, water-removal agent accounts for 3%, dust-proofing agent accounts for 0.7%, coupling agent accounts for 0.6%, Ammonia promotor accounts for 0.8%, rust-stabilising pigment zinc phosphate accounts for 13%, titanium dioxide accounts for 8%, mica powder accounts for 14%, barium sulfate accounts for 16.8%;
The solidifying agent (Bayer DesmodurVL solidifying agent) of B component accounts for 28% of component A gross weight.
The properties test result of material is as following table 3:
Table 3 unmaned platform the performance test results
This example is through test of many times, and this coating application is easy, antikathode stripping energy is strong, antikathode stripping performance is good, can guarantee the quality of buried pipeline preservative coat and joint coating on pipeline.