Anticorrosive paint is a kind of paint that can be used on the surface of objects to protect the interior of objects from corrosion.It is commonly used in industrial constructionpaint, widely used in aviationa shipChemical industry, oil pipeline, steel structurebridge, oil drilling platform and other fields, favored by the majority of construction manufacturers.
There are many kinds of anti-corrosive paint, which can be generally divided into:epoxy anticorrosive paint 、Polyurethane anticorrosive paint、Acrylic anticorrosive paint、Inorganic anti-corrosion paint、PerchloroethyleneAnticorrosive paintChlorinated rubberAnticorrosive paintHCPEAnticorrosive paint;It can be divided into anti-corrosion paint for pipeline, anti-corrosion paint for ship, anti-corrosion paint for metal, anti-corrosion paint for furniture, anti-corrosion paint for automobile and anti-corrosion paint for rubber according to the use;According to solvent, it can be divided into:Waterborne anti-corrosion paintOil based anti-corrosion paint;
Anticorrosive paint is a mixture of various hydrated silicate minerals, and the main chemical group is Al2O3 and SiO2 oxides.Al2O3 mainly comes fromClay mineralIn addition to clay minerals, SiO2 also comes from micro quartz.The closer its Al2O3 content and Al2O3/SiO2 ratio are to the theoretical value of kaolinite mineral, the higher the purity of this clay is.
characteristic
It can be used in severe conditions, and has good durability and weather resistance. It can be used in marine, underground and other severe conditions for more than 10 or 15 years, even in acid, alkali, salt and solvent media, and under certain temperature conditions, it can also be used for more than 5 years.
component
The more kaolinite content in clay, the better its quality.The higher the fire resistance of clay, the wider the sintering and melting range of clay.The main impurities in clay are alkali metals, alkaline earth metals, oxides of iron, titanium, etc., and some organic matters.All oxides play a role of melting aid, which will reduce the refractoriness of raw materials. Therefore, the lower the impurity content in clay, especially the content of Na2O and K2O, the higher the refractoriness.There are many kinds of minerals in clay, but it is usually composed of only 5-6 kinds of minerals, and the main mineral is kaolinite.Common impurity minerals include quartz, hydromica, iron bearing minerals, feldspar, rutile, etc.The content and distribution uniformity of impurities affect the fire resistance of clay.A series of physicochemical changes will occur in the heating process of the anticorrosive paint, such as decomposition, melting, recrystallization, etc., accompanied by volume shrinkage.These changes have an important impact on the process and properties of clay products.Clay raw materials in China, whether hard clay, soft clay or semi soft clay, are mainly kaolinite type.Therefore, the heating change of clay is essentially the heating change of kaolinite and the physicochemical reaction between kaolinite and impurity minerals.Hard clay clinker isClay refractoryThe main raw materials of, are usually obtained by calcining the hard clay raw material blocks directly mined in the inverted flame kiln, rotary kiln, or shaft kiln.
In addition to chemical composition, the production of refractory requires high bulk density, low porosity, low water absorption and full sintering of clay clinker.Therefore, the calcination temperature and holding time have obvious effects on the quality of clay clinker.When the calcination temperature is 1200~1250 ℃, the volume density and porosity of clinker are the best.When the temperature is higher than 1350 ℃, the bulk density decreases and the porosity increases. At this time, a large amount of cristobalite is generated and the volume expands. At the same time, the development of the coke gem layer leads to the cracking of the clinker block. The main mineral phase of the hard clay of the anti-corrosion paint is mullite, accounting for 35%~55%, followed by glass phase and cristobalite.
Epoxy paint is usually used as primer and intermediate paint of anti-corrosion paint.
epoxy anticorrosive paint Composition: it is composed of epoxy resin, antirust pigment and filler, and the curing agent is composed of component 1 and component 2.
Epoxy anticorrosive paint features: water resistance, acid and alkali resistance, good rust resistance.Strong adhesion with steel and cement surface.
Use of epoxy anticorrosive paint: it is suitable for water, oil and water resistance of pipelines, various steel structures, bridges, oil brick well platforms and chemical equipmentChemical ReagentsIt can be used for protective priming, as well as priming of cement substrate or integrated protection of bottom and surface.
Polyurethane series
Anticorrosive paint
Polyurethane anticorrosive paintComposition: It is a two-component self drying paint. The first component is polyester color paste, and the second component is special curing agent.
Characteristics of polyurethane anti-corrosion paint: good anti-corrosion performance.The coating has good adhesion, toughness, abrasion resistance, elasticity and resistance to acid, alkali, salt, oil, petroleum products, benzene solvents, water, boiling water, seawater and chemical industry.
PURPOSE OF POLYURETHANE ANTICORROSION PAINT: It is suitable for anti-corrosion coating of steel structure facilities, gas pipelines, chemical facilities, oil tanks, bridges, wharves, gas cabinets, motors, electrical appliances, aluminum alloys, etc.
Acrylic series
Anticorrosive paint
Acrylic anticorrosive paint:acrylic resin The anticorrosive paint is mainly composed of modified resin, pigments, fillers, additives, solvents, etc.
Characteristics of acrylic anticorrosive paint: The paint film has excellent light and color retention and weather resistance.It has good physical and mechanical properties.The paint film is fast drying and easy to construct. It can be constructed under the temperature of - 20 ℃ - 50 ℃.
Application of acrylic anticorrosive paint: this paint is suitable for anticorrosive protection and decoration of steel structures and concrete.
Characteristics of perchloroethylene anticorrosive paint: the paint has excellent corrosion resistance, acid and alkali resistance, mold resistance and moisture resistance, and poor adhesion. If it is well matched, it can be made up.
Use of perchloroethylene anticorrosive paint: used on metal and wood surfaces of various chemical machinery, pipelines, equipment, buildings, etc., to prevent corrosion of acid, alkali and other chemicals.
Chlorinated rubber anticorrosive paintCharacteristics: It has good acid and salt corrosion resistance, atmospheric corrosion resistance, and good physical and mechanical properties.
Use of chlorinated rubber anti-corrosion paint: mainly used for protective coating of automobile chassis and engineering machinery chassis, or protective coating of equipment, pipelines and metal components under slight erosion.
Performance of high chlorinated polyethylene anticorrosive paint: the film is tough, with excellent weather resistance, corrosion resistance and flame retardancy.It has excellent anti-corrosion performance for industrial atmosphere, "three wastes" polluting medium, acid, alkali, salt, mineral oil and other corrosive medium (ammonia, chlorine, carbon dioxide) with different concentrations
toochlorinated polyethylene Use of anticorrosive paint: applicable to steel structures and concrete facilities such as petrochemical industry, metallurgical mines, building plants, transportation facilities, ship bridges, engineering machinery, sewage treatment, etcIndustrial floorAnd other anti-corrosion works.
Inorganic anti-corrosion paint
Anticorrosive paint
Inorganic anti-corrosion paint ZS is composed of new inorganic polymer, dispersed activated metalmetallic oxidenanometer materialInorganic polymer coatingIt can quickly react with the iron atoms on the surface of steel structure to generate a high-tech product that has the dual physical and chemical protection effect, no pollution to the environment, long service life, and anti-corrosion performance reaching the international advanced level.
construction
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Surface preparation
If there are impurities, oil, grease and scale on the surface, they should be cleaned according to the cleaning method specified in the Specification for Steel Surface Preparation before Painting (SY/T0407).
The steel surface shall be derusted by spraying according to the method specified in SY/T0407.The spraying operation shall be carried out in the order of top, wall and bottom.The derusting quality shall reach Sa2.5 specified in Rust Grades and Derusting Grades of Steel Surfaces before Painting (GB/T8923-1998). The depth of anchor lines shall be selected according to the anti-corrosion grade, and the ordinary type: about 40 μ m.The 6-8mm nozzle is selected. The compressed air pressure at the nozzle inlet is 0.5-0.6Mpa, the spray angle is 30-75 °, the incidence distance is 100-200mm, and the sand particle size is 0.8-4 mm.When the thin steel plate is sandblasted, the sand particle size and air pressure shall be properly reduced. When the abrasion of the sandblasting outlet end and diameter exceeds 1/2 of the initial inner diameter, the nozzle shall not be used any more.The surface preparation of accessories shall be the same as that of the main parts.
After spraying treatment, the surface shall be purged with dry, clean and oil-free compressed air.
After spray derusting, the defects exposed on the steel surface and welds must be treated.
Safety measures: keep ventilation so that the concentration of solvent gas is lower than the dangerous concentration. The spraying operator shall wear protective clothing and mask. The spraying pipe shall be cleaned immediately after grounding and contacting the nose.
Coating preparation
If anti-corrosion paint isTwo component paintBefore coating, the two components can be mixed and prepared. Before preparation, confirm whether components A and B are matched, whether they are consistent with the required coating model, and whether they are invalid.
A. Group B must be stirred until there is no sediment at the bottom and the top and bottom are uniform before dispensing.
Prepare a small amount of uniform components A and B for trial coating according to the proportion required in the instructions, adjust the viscosity with special diluent to optimize the coating process conditions, and ensure the thickness and quality of single film.
Calculate the amount of components A and B according to the coating area and the thickness of single coating film, and control the amount of ingredients to be used up within 6 hours, so as to prevent the excessive amount of ingredients and the excessive thickening of the coating due to the application timeout from affecting the quality of the coating film.
The amount of special diluent for coating shall be controlled not to exceed 15% (spraying) or 8% (brushing) of the total weight. Add component A according to the calculated proportion and mix evenly. Then add component B and mix for 10-15 minutes to ripen components A and B, and finally stand for 15-20 minutes to eliminate the air bubbles introduced by mixing.The length of mixing and standing time depends on the amount of ingredients.
The mixed coating can be sprayed only after being filtered with a 100 mesh filter screen.Once the coating becomes thickened due to excessive reaction during spraying, the spraying shall be stopped immediately.If the coating has been scrapped, it shall be re batched.The excessive reaction time of the coating is related to the ambient temperature. When the temperature is high, the time required is short, and the material should be prepared less. On the contrary, when the temperature is low, the time required is long, and the dosage should be increased appropriately.
Coating process
During specific construction, the coating process procedures and measures to ensure the quality of anti-corrosion coating shall be prepared according to the structure of anti-corrosion articles.
The environmental conditions during coating shall meet the requirements of the instructions.In case of rain, snow, fog, wind and sand and other climatic conditions, the outdoor construction of anti-corrosion coating shall be stopped.When the construction environment temperature is lower than - 5 ℃ or higher than 40 ℃, or the relative humidity is higher than 80%, the construction is not suitable.The uncured anti-corrosion coating shall be protected from rain.
If corrosion occurs within the interval between the qualified surface pretreatment and the application of the first primer, the surface of the corroded parts shall be pretreated again before application.Large containers that cannot be sandblasted within one day shall be sealed to prevent convection with external generation gas and extend the time of rust return.
Chlorosulfonated polyethylene anticorrosive paintCoating can be adoptedAirless sprayingAir spraying, brush coating, roller coating and other construction methods shall be applied in a top-down order. The coating shall be uniform and shall not be missed. The application method shall be determined according to the anti-corrosion construction scheme.The coating operation shall meet the following requirements:
A、When the brushing method is used for construction, the application force shall be uniform and brushed in the same direction to avoid surface fuzzing.
B、When spraying, the moving speed of the spray gun shall be uniform, and the nozzle shall be vertical to the surface to be sprayed.
C、When the roller coating method is used for construction, the roller dip material shall be uniform, not too much, and the force shall be uniform, not too large, and the speed shall be kept constant;The roller shall be rolled in the same direction, and the direction of each pass can be different.The corners, accessories and other parts that cannot be coated by the roller shall be coated with brush tools.
Welds, corners and uneven parts on the surface shall be dipped with more paint or coated more times.
The application interval of each coat of paint shall not be more than 24 hours. The next coat of paint should be applied after the surface of the previous coat of paint is dry.If the previous coat of paint has been cured, roughen it before applying the next coat of paint.After the last finishing coat is coated, it should be cured at 25 ℃ for more than 7 days before being put into use.If the curing temperature is lower than 10 ℃, it should be cured for more than 10 days before being put into use.
During construction, the wet film thickness of the coating shall be measured at different parts, and the coating viscosity and coating process parameters shall be adjusted in time to ensure that the final thickness of the anti-corrosion coating meets the design requirements.
matters needing attention
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stayAnticorrosive paintBefore construction, two points must be paid attention to. One is the danger to human health;The second is the danger of explosion.It is important to understand the product safety regulations before painting.Such as Jinnuoxin acrylic engineering primer and JinnuoxinAcrylic engineering finishAlthough there is only a word difference and similar functions, attention should be paid to the matching and use. Once an accident occurs, it will endanger human health.
Development trend
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1、 Develop water-based anti-corrosion primer and finish for steel structures
Waterborne anti-corrosive primer must solve the problem of idle corrosion and poor water resistance of substrate.
The emergence of some new emulsifier free emulsions has fundamentally improved their poor water resistance. In the future, we should focus on solving the problems of construction function and application function.
As a topcoat, it is mainly to improve its decoration and durability under the condition of ensuring the protective function.
2、 Development of High Solid and Solvent free Anticorrosive Coatings
There is a big gap between China's products and foreign investors in terms of comprehensive strength, such as technical level, economic strength, quality assurance system and product reputation, and it is difficult to enter the market.
For this reason, efforts should be made first in the technical development, especially in the development of lead-free and chromium free antirust paint primers, namely zinc phosphate andaluminium triphosphate Main anti rust primer.
The water-based inorganic zinc rich primer with high modulus potassium silicate as the base material is a proven high-performance primerAnticorrosive coating, with development potential.
4、 Development of Room Temperature Curing Heat Resistant and Anticorrosive Coatings for Heat Exchangers
Heat exchanger needs heat resistant and high thermal conductivityAnticorrosive coating。The epoxy amino coating used needs to be cured at 120 ℃, and needs multiple coats, so it can not be used in large units.
5、 Develop coatings that can be cured at room temperature and easy to apply
The key point is to find the best balance among the anti-corrosion function, heat transfer function and constructable function of the paint.
Because chlorinated rubber is a single component, convenient for construction, excellent in water resistance, oil resistance and atmospheric aging resistance, it is widely used in ships, industrial anti-corrosion and other fields, and has a broad market.
But because the chlorinated rubber produced uses CC1 as the solvent, it destroys the ozone layer.Therefore, developed countries have developed their substitutes.The more successful ones are MP chloroether resin series and aqueous phase method of German BASTchlorinated polyethylene Or modified products.
7、 Development of Flake Anticorrosive Coatings
Micaceous iron oxide(MIO) has excellent medium resistance, atmospheric aging resistance and blocking function, and is widely used as primer and finish in Western Europe.
There is a certain gap between domestic MIO and foreign MIO in terms of particle size distribution, diameter thickness ratio, density, etc.stayGlass flake coatingThere are similar problems in the development of.
