Anhui Seagal Coating Technology Co., Ltd.

——Description of Heavy-duty anti-corrosion of iron tower

Part 1  Overview

Iron tower anti-corrosion is a systematic project and needs cooperation in all aspects. A problem during operation may cause failure of anti-corrosion. In summary, the main influencing factors can be divided into three aspects: the surface treatment of steel products, the selection of anti-corrosion paint systems, and the construction technology.

1. Surface Treatment

Before sandblasting, pre-treatment should be carried out, including smooth smoothing of welds, welding repair of undercut pores, chamfering of sharp edges, etc. The surface oil is cleaned with a cleaning solution. Sandblasting and derusting grades shall meet the national standard GB/T8923-1998 "Corrosion Grades and Derusting Grades of Steel Surfaces Prior to Coating" Sa2.5 (Steel should be free of visible grease, dirt, scale, rust, and paint. Layers and other attachments, the surface should show a uniform metal color). During the sandblasting process, the components that are not well derusted are manually derusted and reach the manual derusting standard St3. Surface treatment is very important for corrosion protection of steel structures. In comparison, for the same paint and the same corrosive environment, the use of shot blasting and sand blasting can extend the life by three to five times compared to manual rust removal.  After the sandblasting process is completed, the primer should be applied as soon as possible, and the coating time should be within 4 hours when the blasting process is completed. If secondary rusting occurs, it must be lightly blasted or manually removed to ensure coating quality.

Part 2、Coatings selection and coating process

2.1 Water-based epoxy zinc-rich primer

Spray two layers with dry film thickness of about 100μm, divided into two layers. Water-based epoxy zinc-rich rust proof primer 2. The dry film thickness is not less than 2×50μm, the use of water-based epoxy zinc-rich primer, the solid material slowly added to the liquid material according to ratio requirements. Adding should be operated with stirring. Stir thoroughly and evenly. Ripening requirements should be matured according to the time specified by the manufacturer, and stirring should be done frequently during use to ensure the uniformity of the coating. Spraying requires the next coat to be applied after the shortest overcoating interval.

2. Middle paint (waterborne epoxy iron coating)

Spray a dry film with thickness of 50μm.。 Use water-based epoxy iron as middle paint. Mix the two components as required. If there is requirement of ripen the product, please refer to the time required by the manufacturer. Stir frequently during use to ensure coating homogeneity. Spraying requires the next coat to be applied after the shortest overcoating interval.

3. Finish coating (water-based acrylic anti-corrosion paint or water-based epoxy anti-corrosion paint)

Spray two dry films with thickness of 50μm ，The air spraying method must keep the compressed air clean, and the filter in the oil-water separator should be replaced regularly; First up and down, then left and right, or first, left and right, top and bottom vertical and horizontal method; structural spray gun and coated object at the same horizontal distance; operation to prevent spray gun from long distance or arc wave.

TWO：Cautions

1. It should be carried out strictly according to the manufacturer's painting process, because the painting operation has a great influence on the properties of the coating. In particular, many excellent anti-corrosion coatings are extremely sensitive to the operation method. It is recommended that special personnel perform the construction.

2. To ensure the thickness of the coating, the thickness of the anti-corrosion coating must reach a certain critical thickness in order to achieve a certain degree of protection.

3. Diluent shall use tap water or purified water.

Part 2  Product intro

Steel structure heavy anti-corrosion technology (waterborne epoxy rich-zinc primer) introduction

At present, the curing mechanism of water-based epoxy zinc-rich primer as a heavy anti-corrosion primer is subject to epoxy curing with a curing agent. The addition of a curing agent can adjust the length of the curing time. Temperature is the main factor affecting the curing speed. Increasing the ambient temperature can increase the curing speed. The auxiliaries often used in the FRP process are curing agents and accelerators. The accelerating agent can accelerate the curing speed. Both are added to the resin in a certain proportion, that is, the curing speed required for the glass process can be adjusted.

The following waterborne epoxy zinc-rich primers are described as follows. This primer is a three-component, fast-drying, water-based primer containing a new modified epoxy resin, herein contained a curing agent and a large amount of specially treated active zinc powder to inhibit corrosion. Due to the resin used in this primer, special synthetic techniques and synthetic techniques are used to make it better quality of the film formed during curing, and the zinc powder has also undergone special treatment and improvement. It can better exist in the paint film, but not easy to be oxidized, so as to play a better role in anode protection, so it has the performance that ordinary epoxy paint can not reach, in terms of corrosion resistance and coating stability ideology is more prominent.

Engineering Conditions

Substrate temperature must not be lower than 10°and should be at least 6°or more above the dew point of the air. Temperature and relative humidity should be measured near the substrate. Good ventilation is usually required to ensure proper drying, especially in closed area.

Since the zinc powder in the primer is easy to settle, the primer in the bucket must be frequently stirred during the painting to ensure the uniformity of the primer.

Manner of application

Spray coat    Use airless spray or air spray.

Brush coat    It is recommended for pre-coating and small-area coating, but the required dry film thickness must be achieved.

Roll coat      It can be used in small areas, but it is not recommended as the first primer. In the case of roller coating, sufficient materials must be applied to achieve the specified dry film thickness.

Engineering Specs

Mixing ratio (mass ratio): A component: B component: C component = 5:1:15

In order to ensure proper mixing, components A and B should be mixed well with a mechanical stirrer before mixing, and then add component C (Be careful when adding metal powder). If the viscosity is too high, a certain amount of water can be added until the process is over.

After the three components are mixed, they should be mixed together with a mechanical stirrer and stirred until they reach the bottom of the barrel (stirring for at least 15 minutes). Pay attention to use 80 mesh screen before the process.

The service life after mixture（23℃）is 8 hours. Attn: The paint can no longer be used beyond its service life.

Thinner/cleaner   water

Spraying parameters  When applying by spray coating, it is necessary to adjust according to the actual spraying conditions. It is recommended to test the spray in a small area and obtain the proper spray parameters before coating.

Cautions

Construction equipment preparation and cleaning procedures

In order to avoid contamination of the waterborne paint by the solvent, the spray equipment must be properly adjusted before use. All solvent-contacting pumps, tubes, guns, etc. must be thoroughly cleaned according to the following steps:

If the construction equipment is made of stainless steel and is used exclusively for the construction of water-based paints, this preparation and cleaning work is not required.

Before spraying: Rinse with water in equipment and pipes until it is thoroughly clean.

After spraying: Rinse the equipment and piping with water and leave no residual paint.

Steel structure heavy anti-corrosion technology (waterborne epoxy iron coating material) introduction

Product Intro

The water-borne epoxy iron coating is a two-component waterborne epoxy amine cured coating which contains active anti-rust pigments and a large amount of lamella iron oxide.

Recommended Applications

As a water-based epoxy zinc-rich primer or water-based inorganic zinc-rich primer coating, it is to increase the duration time in steel structure in moderate to severe corrosive environments. The steel surface can be coated with water-based acrylic, water-based epoxy, water-based polyurethane and suitable Solvent-based paints.

Surface Treatment

All surfaces should be clean, dry and free from dirt, and the surface should follow ISO8504 before evaluation and processing.

Steel coated with primer

clean, dry and approved primer

Steel coated with waterborne epoxy zinc-rich primer or waterborne inorganic zinc-rich primer

Clean and dry primer. Sand blast is needed if primer exceeds the maximum re-coating interval.

Engineering Conditions

Substrate temperature must not be lower than 10°and should be at least 6°or more above the dew point of the air. Temperature and relative humidity should be measured near the substrate. Good ventilation is usually required to ensure proper drying, especially in closed area.

Manner of application

Spray coat    Use airless spray or air spray.

Brush coat    It is recommended for pre-coating and small-area coating, but the required dry film thickness must be achieved.

Roll coat    It can be used in small areas, but it is not recommended as  the first primer . In the case of roller coating, sufficient materials must be applied to achieve the specified dry film thickness.

Engineering Specs

Mixing ratio (mass ratio)  Group A：Group B=10∶1,stir evenly.

In order to ensure proper mixing, the two groups should be mixed with a mechanical stirrer while mixing. At the same time, the two components should be mixed with a mechanical stirrer and stirred to the bottom of the barrel. ( at least 2 minutes)

service life after mixture（23℃）is 4hours Attn: The paint can no longer be used beyond its service life. It is recommended to use the alarm to remind if the time exceeds the service life.

Thinner/cleaner:  water

Spraying parameters: When using spray coating, adjust according to actual spraying conditions.

It is recommended to spray the small area first and obtain the proper spraying parameters before painting.

Cautions

Construction equipment preparation and cleaning procedures

In order to avoid contamination of the waterborne paint by the solvent, the spray equipment must be properly adjusted before use. All solvent-contacting pumps, tubes, guns, etc. must be thoroughly cleaned according to the following steps:

If the construction equipment is made of stainless steel and is used exclusively for the construction of water-based paints, this preparation and cleaning work is not required.

Before spraying: Rinse with water in equipment and pipes until it is thoroughly clean.

After spraying: rinse the equipment and piping with water and leave no residual paint.

Steel structure heavy anti-corrosion technology (waterborne acrylic anti-corrosion topcoat) introduction

The product uses modified acrylic resin as the copolymer to disperse the oil-soluble resin in water to form a thermodynamically stable system. It also integrates the compounding technology of oxidizing and self-emulsifying resins, and has strong adhesion, water resistance and resistance, salt-resistance, alkali-resistance, acid-resistance and weather-resistance. This product absorbs the unique formulas and processes of the essence of waterborne anti-corrosion topcoats, poly-crosslinking, reactive, and emulsifying at home and abroad. It is scientifically based on self-emulsification, taking into consideration the design of cross-linking and reaction-type.  The selection of ultra-fine inorganic and non-toxic pigments has enabled the new generation of water-based anti-corrosion topcoats to add the best products for the renewal of anti-corrosion coatings.

The product uses inorganic non-toxic raw materials, rational use of nano-materials, selected part of the inorganic organic water-based high polymer, self-emulsified water-based resin. With water as a diluent, it is non-toxic, odorless and generates no pollution or three wastes. It is non-flammable, non-explosive, VOC is less than 38, ensuring environmental protection and fire safety, and protecting the health of workers.

Surface requirement
Before coating, it is necessary to check whether the primer on the surface of the painted part is completely dry. The surface of the primer should not be stained with oil, dirt, etc., the surface of the primer should not be damaged. The primer must be thoroughly dried to remove the oily lime sand and the bottom surface is smooth. Construction can be done under non-destructive conditions.

Operation environment
shall be done on sunny days. The best operation condition is the ambient temperature 5-40 °C, relative humidity less than 80%. The temperature can't be below 3 °C, and the environment humidity is greater than 80% . The painted coat can not be moist by rain within 4 hours, and no water rinse.

Methods
This product is suitable for brushing, spraying, airless spraying, dipping, but the spraying pressure should be in the range of 0.25-0.5Mpa, high pressure airless spraying, nozzle pressure should be controlled in the range of 12-15Mpa.

Steel structure heavy anti-corrosion technology (waterborne epoxy anti-corrosion finish coat) introduction

Product Intro

Water-based epoxy anti-corrosion paint is a two-component amine-cured waterborne epoxy anti-corrosion paint.

Surface Treatment

All surfaces should be clean, dry and free from dirt, and the surface should follow ISO8504 before evaluation and processing.

Engineering Conditions

Substrate temperature must not be lower than 10°and should be at least 6°or more above the dew point of the air. Temperature and relative humidity should be measured near the substrate. Good ventilation is usually required to ensure proper drying, especially in closed area.

Manner of application

Spray coat    Use airless spray or air spray.

Brush coat    It is recommended for pre-coating and small-area coating, but the required dry film thickness must be achieved.

Roll coat    It can be used in small areas, but it is not recommended as the first primer . In the case of roller coating, sufficient materials must be applied to achieve the specified dry film thickness.

Engineering Specs

Mixing ratio (mass ratio)   Group A：Group B=2∶1,stir evenly.

In order to ensure proper mixing, the two groups should

be mixed with a mechanical stirrer while mixing.

At the same time, the two components should be mixed

with a mechanical stirrer and stirred to the bottom of the barrel. (at least 2 minutes)

service life after mixture（23℃）is 2hours Attn: The paint can no longer be used beyond its service life. It is recommended to use the alarm notice before its expiry.

Thinner/cleaner:  water

Spraying parameters:  When applying by spray coating, it is necessary to adjust according to the actual spraying conditions. It is recommended to test the spray in a small area and obtain the proper spray parameters before coating.

Cautions

Construction equipment preparation and cleaning procedures

In order to avoid contamination of the waterborne paint by the solvent, the spray equipment must be properly adjusted before use. All solvent-contacting pumps, tubes, guns, etc. must be thoroughly cleaned according to the following steps:

If the construction equipment is made of stainless steel and is used exclusively for the construction of water-based paints, this preparation and cleaning work is not required.

Before spraying: Rinse with water in equipment and pipes until it is thoroughly clean.

After spraying: Rinse the equipment and piping with water and leave no residual paint.