Steel structure anti-corrosion new material - winter polyp

Steel structure anti-corrosion construction process is generally surface treatment and anti-corrosion coating, from the most common primer finish to add the middle layer, the most classic coating structure: zinc-rich (inorganic zinc-rich, organic zinc-rich) and epoxy cloud iron and acrylic polyurethane (fluorocarbon paint or polysilica, etc.).
this system is widely used in steel construction plants and mesh sheds, bridges, pipe racks, wire rods, photovoltaic power stations, wind turbines and some marine projects, and achieves long-term anti-corrosion effect.
But this classic matching coating structure multi-layer coating takes time (with long layer coating intervals) and can make it difficult to overcome some short-term repairs or duration emergency projects.
This paper discusses the excellent characteristics of the winter polysaccharides and the application of single-layer supporting process with zinc-rich bottom coating in the corrosion prevention of steel structure, this novel coating supporting process is an innovation of traditional steel structure corrosion protection, especially in environmental protection, labor saving, reduce material costs is very obvious.
-day winter polyp research and development background 1.1 no VOC construction exemption conditions after anti-corrosion coating research and development personnel and anti-corrosion construction technicians continue to explore the practice, a steel structure anti-corrosion new material - tiandong polysaccharus solves the above difficulties, and can meet the environmental protection requirements of the construction exemption conditions without VOC.
7.2.1 of the latest GB378222-2019 Volatile Organic Unwed Emission Control Standard: VOCs ≥10% of quality with VOCs Products, the use of the process should be closed equipment or in an airtable space operation, exhaust gas should be exhausted to voCs exhaust gas collection and treatment system;
1.2 Environmentally friendly coatings in winter polycepts containing VOCs products, including but not limited to the following operations: coating (spraying, immersion, spray coating, roller coating, brushing, coating, etc.).
This strictly defines the scope of coating environmental restrictions, VOCs quality ratio≥10% of the construction must be set up exhaust gas collection and treatment system (this is the conventional heavy anti-corrosion construction site difficult to meet the hard requirements, reverse paint production enterprises or use units must use water-based paint or solvent-free paint) that is, no solvent or solid content>
the winter polysaccharies fully comply with the above requirements. The excellent performance and supporting system of
days of winter polypropyl, 2.1 days of winter polysaccharide corrosion resistance and the applicable period of winter polysaccharides is a new type of fat family, slow reaction, high-performance coating material, known as the third generation of polysaccharides, is actually a kind of adipose family mid-amine.
when the coating is exposed to ultraviolet light requires a high degree of stability, it is necessary to choose a fat family coating system - winter polysacchargium.
polycycline viscosity is low, and the reaction speed of HDI trimer can be different to replace the base group, gel time from 5 min to 120 min, construction life can be extended from 5 min to more than 2 h, spray together can reach 0. 6 mm, no pores on the coating surface, wide adjustable range of the formulation system, good resistance to UV rays, long-lasting gloss, stable color, not yellowing, small material loss when spraying, solid content can be adjusted from 70% to 100%.
days winter polysaccharides with high solid content and low viscosity (solid content >90%, or even up to 100%) ultra-strong UV resistance, wear resistance, good flexibility, resistance to less than 5% acid and alkali and some chemical media, thick coating construction, can be sub-zero rapid curing and so on.
in accordance with the "HG/T 5368-2018 poly-tianmen anti-corrosion coating" standard, the winter polyurethane DTM can be applied to C4 and below light anti-corrosion occasions alone; Corrosive environment can be used as finish and epoxy and other primers, the package is recognized and in the latest version of ISO12944-5:2018 color paint and varnish protective paint system corrosion protection of steel structure.
2.2 surface treatment requirements and coating system supporting the combination of winter polysaccharides and zinc-rich primers>5MPa, salt-resistant fog up to more than 3000 h.
the most classic steel structure corrosion-resistant coating from zinc-rich (inorganic zinc-rich, organic zinc-rich) and epoxy cloud iron and acrylic polyurethane (fluorocarbon paint or polysilica, etc.) can be optimized for: zinc-rich (inorganic zinc-rich, organic zinc-rich) and winter polysaccharide coating system, greatly reducing the construction cycle and labor costs.
this anti-corrosion coating coating supporting system not only meets the requirements of construction environmental protection, but also is a technical revolution and coating innovation. The choice of zinc-rich primer in
system requires the surface treatment of steel structure to meet the requirements of Sa2.5 grade and related soluble salts as stipulated in the Visual Assessment of Surface Cleanliness of Steel Surface Treatment before GB/T 8923.1-2011 coating.
when the metal surface is cleaned by injection, a certain degree of surface roughness or surface contours is obtained. the formation of
roughness will make the area of the metal surface significantly increased, while obtaining a lot of anchoring points, easy to cause the coating film at the peak is thinner, and too large roughness will be due to poor coating immersion of the substrate caused by the coating corrosion and attachment reduction.
removal of rust, dirt and old coatings, the steel surface is not clean enough to be painted, especially soluble salts are more harmful to the coating.
soluble iron corrosives may continue to contaminate rusted steel because corrosive substances such as salts are almost colorless and can be hidden deep in pitting so that they cannot be effectively removed.
surface treatment level is lower than Sa2.5, soluble corrosives are hidden under layers of iron oxide.
these corrosion products are usually water-soluble iron chloride and iron sulfate, and the coating will cause the paint film to blister during later use.
, these soluble salts must be removed or lowered to an acceptable standard before painting.
steel structure surface treatment in line with the above roughness and cleanliness before the coating, under normal circumstances zinc-rich coating thickness is basically controlled between 60 to 80 m.
days of winter polysorbent in a variety of corrosive environment applications if underwater immersion or weather resistance requirements are not high in the occasion can choose for example GB805B-100 polyether-modified pre-concentration curing type of winter polysaccharide, its green environmental protection, solvent-free, low viscosity, an facade construction up to 500 m thick, with a longer construction application time.
painting, rolling coating, spraying can be, flexible and convenient construction.
paint film strength, flexibility, wear resistance, excellent anti-flush, and zinc-rich can match the advantages of good.
but the polyether structure determines that its weather resistance does not meet the corrosion environment requirements of C5.
, it is recommended to choose HDI trimer type of adipose group winter polysaccharid in outdoor weather-resistant situations, with excellent weather resistance and aesthetic performance.
fast-drying type fat family tiandong polysaccharides in manual brushing, rolling coating construction applicability is not as good as polyether modified pre-accumulated solidification type winter polysaccharides, the applicable period by the construction of solid content is more affected.
e.g. up to 0.5 h;90% and solvent-free less than 10 min when the quality is 75% solid, so if you want to meet the environmental requirements of VOCs,lt;10%, you can use a dedicated dual Component spraying equipment for construction, coating thickness can be up to 200 m, consumption of about 0.5 kg/m2, can be normal curing at -10 degrees C, at room temperature table dry 20 min, dry 40 min, can be quickly put into use.
another technical solution is the use of gel time 2 h of slow-dry poly-tianmen hololine resin made of winter polysaccharide paint, coating application period can be extended some, but the drying time will also be extended to 8 h.
zinc-rich (inorganic zinc-rich, organic zinc-rich) and winter polysaccharide two coating systems can meet the ISO-12944:2018 supporting system thickness requirements, in the C5 atmospheric corrosion environment can reach 30a service life.
with the technological progress and rapid growth of the use of steel structure industry, the quality requirements, service life and cost-effectiveness of steel structure coating, especially anti-corrosion coating, have correspondingly put forward higher goals.
According to incomplete statistics, in 2019 the national steel structure use of more than 70 million t, the number of materials used for corrosion-proof coating is huge, labor costs, coating material costs, time cost is the largest cost of construction and construction costs.
faced with huge construction cost pressure and environmental restrictions, the construction department has been looking for the best coating materials, whether from the cost-effective or from environmental requirements, the winter polyp has irreplaceable forward-looking advantages.
-rich (inorganic zinc-rich, organic zinc-rich) and winter polysaccharide coating system in large-scale steel structure corrosion-resistant coating industry will show strong vitality, and tend to improve.
Encion and the country's top producers of winter polysaccharides will be zinc-rich (inorganic rich zinc, organic zinc-rich) and winter polysaccharide two coating systems successfully applied to the outer wall of wind turbines and auxiliary steel structure corrosion-resistant coating field, and achieved good economic benefits and practical expected results.
(slightly) author zhang Zuhua (Shanghai Ensho Industrial Co., Ltd., Shanghai 201703) the full content of the "coating and protection" 2020-10