Water-based industrial paint coating process construction!

The decoration, protection and functional effect of the coating on the surface of the object to be coated is embodied by the coating film formed on the surface of the object
.
The process of forming the required coating film on the surface of the object to be coated is commonly referred to as coating construction, also known as painting
.
For water-based industrial paints, construction is more important.
Paint online coatingol.
com
.
As a commodity, water-based industrial paint circulates in the market.
It is actually a semi-finished product of the coating film.
Only when the coating film is formed by painting can it play its role and have use value
.

The quality of the coating film directly affects the decorative effect and use value of the coated object, and the quality of the coating film depends on the quality of the coating and coating
.
The quality of the coating performance is usually evaluated by the quality of the coating film
.
Inferior coatings or unqualified coating products cannot get a high-quality coating film .
If the high-quality paint is improperly applied and operated by mistake, it will not be able to obtain the excellent coating film and achieve the desired decorative or protective effect
.
The correct coating application can fully reflect the performance of the coating on the coating film, and the improvement of coating technology further improves the performance of the coating to form a coating film
.

Control the temperature and humidity control during the construction of water-based industrial paint, and the performance will be significantly improved

1.

The surface treatment of the substrate of the coated object, also known as the pre-paint surface treatment, is the basic process of paint construction

There are often rust, oxide scale, oil stains, etc.

From the perspective of polymer technology, the coating not only produces a polymer film, but it is also a good adhesive
.
Mere plastic film does not prevent metal corrosion, it must be tightly bonded to the steel surface
.
Oil stains and rust on the surface of steel will obviously affect the adhesion and protective performance of the coating.
Therefore, the treatment of the metal surface must not only remove rust, but also remove oil
.

In order to obtain a good anti-corrosion coating, surface treatment is an important preparation process

Steel surface treatment methods can be divided into two categories: mechanical methods, such as sandblasting, shoveling, etc.

2.

That is, using different methods, tools and equipment to evenly coat the coating on the surface of the object to be coated

The coating of water-based industrial paint generally includes brushing, roller coating, spraying and dipping, etc.
The factors affecting the construction method generally include: investment costs, operating costs, paint film thickness, appearance requirements and the structure of the coated object
.
The reduction of VOC (volatile organic compound) emissions is the driving force for the improvement of the construction method.
The construction method has an impact on the amount of solvent required and the recovery of the solvent.
The solvent or diluent used in the water-based industrial paint is water, and the water is removed from the paint film.
The volatilization rate directly affects the effect of the paint film after construction, and also affects the coating substrate.
For example, the substrate is ordinary carbon steel, and the slower water volatilization will cause the corrosion of the steel.
The substrate is wood, and the water volatilizes.
Slow will bring about the swelling of wood fibers, and wood thorns and wood wool become obvious
.

(1) Brushing

Water-based paints are generally non-Newtonian fluids with certain thixotropic properties.
The leveling performance of the paint film after brushing is slightly worse than that of solvent-based paints
.
Brushing is not recommended for coatings with higher decorative requirements .

(2).
Roller coating
.
Roller coating refers to the method of manual roller construction.
It is the fastest method of manual construction and is widely used to paint architectural coatings on walls and ceilings
.
Various rollers and roller coverings are used, and different patterns can be painted by rollers through the modeling of different coverings on the rollers
.

The requirements for viscosity are similar to brush application, and when the paint is applied with a roller, the coating film will crack
.
When the roller is moving, the coating film is stretched, and the coating film flows in an extended manner.
Due to the pressure imbalance, the coating film cracks at different times, leaving a ridged surface
.
Some of the coating film stretches away from the nip between the two rollers and stretches to the fiber.
When the roller moves, the fiber is pulled to minimize the surface area of ​​the applied coating, but if there is not enough time to produce leveling at low viscosity If so, it will leave the impression on the coating
.

(3).
Spraying
.
Generally, water-based coatings are suitable for spraying processes, but their rheological problems are more prominent than brushing
.
Thickeners can be appropriately used to adjust the rheology, which is convenient for dilution in order to improve the spraying efficiency.
In actual construction, it is found that the rheological properties change too much during the dilution process.
This is related to the non-solution system of the water-based paint itself
.

The paint film of water-based industrial paint dries slowly, but the opposite is true during the spraying process.
The paint will dry and agglomerate near the nozzle of the spray gun, and pile up to form a blockage
.
If the paint sprays away from the nozzle and dries quickly, it is difficult to form a continuous paint film after reaching the surface of the workpiece
.

The atomization of the coating is very important in the spraying process, and the quality of the atomization directly affects the coating and film effect
.
Can be improved by spraying

Certain aspects of performance, such as improving spraying ability, smoothing coating, adapting to high-viscosity coatings, reducing spraying time and atomization loss to improve material utilization
.

Using compressed air for traditional spraying, the pressure of compressed air is generally 0.
6-0.
8MPa.
The degree of atomization of the paint is determined by the weight ratio of the paint to the air flow.
Increasing the air flow and reducing the viscosity of the paint can reduce the average diameter of the paint particles
.
Part of the paint mist during the spraying process does not form a real coating, and it is scattered with the air or sprayed onto the water curtain, forming waste during spraying, which must be cleaned up.
If it cannot be reused, it must be incinerated
.

In order to improve the efficiency of spraying, many workpieces now use high-pressure airless spraying.
The paint is directly pressurized and atomized, which reduces fog and improves the efficiency of coating conversion
.
Strong spraying ability, can spray thick paint film and high viscosity paint at one time
.
High-pressure airless spraying equipment is thicker than ordinary airless spraying equipment.
Due to the high pressure, occupational safety requirements are also higher
.
High-pressure airless spraying is suitable for large-area painting, and the requirements for the appearance of the coating are general
.

When high-pressure airless spraying is used for water-based industrial paints, attention should be paid to the rheological properties of the paint.
The continuous high shear stress of the paint should be pumped
.
The paint raw materials are required to have high mechanical resistance and the paint should be stable during pumping .
The air mixing process is the product of the combination of airless and air spraying
.
The principle of fluid mechanics is directly used for transportation and atomization, and the paint is atomized again by compressed air after leaving the nozzle
.
This method can be used to spray paint with higher viscosity, and the fineness of atomization and dispersion is also very small, and the outline of the sprayed paint is not clear
.

Regardless of the spraying method, it should be selected according to the shape and knot of the specific workpiece, and verified by actual spraying.
Only the coating that meets the actual coating and efficiency requirements can be applied in the factory
.

(4) Dip coating
.
Dip coating is a traditional method in the coating process
.
Its process is to immerse the workpiece in the paint solution, remove the remaining paint after taking it out, and dry it to form a film
.

The characteristics of dip coating are: the coating process is simple, the production efficiency is high, and the coating process is easy to mechanize
.
The coating equipment is simple and suitable for coating the primer of the workpiece
.
The dip coating process requires a simple shape of the workpiece
.
When the workpiece is taken out from the tip, the paint solution will not be retained, and the remaining paint can flow down evenly, so the inner wall of the workpiece with large concave and convex, such as the workpiece with deep grooves, blind holes, etc.
, as well as the workpiece floating in the paint solution.
Suitable
.
Dip coating is selective for coatings.
Dip coating is not suitable for paints that are easy to crust and deposits
.

The main factors affecting the quality of dip coatings are the viscosity and temperature of the water-based industrial paint
.
Viscosity not only affects the thickness of the coating, but also affects the speed of the water paint flowing down from the surface of the coating
.
The lower the viscosity of the water paint, the faster its downstream speed is beneficial to the removal of residual paint
.
If the viscosity is too small, the paint film will be too thin, and if the viscosity is too large, the paint thickness will be uneven
.
The temperature of the paint solution directly affects the viscosity, so it can be used to adjust the viscosity of the paint solution to meet the expected requirements
.
However, it must be noted that the temperature of the paint solution is high and the solvent evaporates quickly
.
For dipping paint, the temperature should be 20-30 degrees Celsius, followed by the uniformity of water paint
.
In order to make the thin layer of paint film have good hiding power, water paint with high hiding power is often used
.

The hanging and transportation of the workpiece is also related to the quality of the coating
.
In order to make the coating uniform, the best hanging position of the workpiece should be that the largest surface position on the workpiece is close to vertical and the other surfaces are inclined to the horizontal plane
.
When the workpiece enters the groove, it is necessary to prevent air bubbles from being generated
.
In the process of removing residual paint and drying, it is best to keep the position of the workpiece as it was when it was painted
.

According to the overall dimensions and production batches of the workpiece, there are two types of dip coating methods: intermittent and continuous
.
The intermittent coating equipment is a fixed tank, which is used for small batch production.
It uses a jib crane, balance crane, monorail, etc.
to transfer workpieces
.
Continuous coating mainly adopts ordinary, catenary or push rod catenary to transport workpieces for mass production
.

In the coating process, it is generally not announced to add new paint
.
It cannot be stirred either
.
Due to the formation of bubbles in the dipping paint during paint injection and mixing, which will affect the quality of the paint film, regular mixing should be used
.
After stirring or after injecting new paint, it should be allowed to stand for a certain period of time until the bubbles are eliminated, and then dip coating
.

3.
The coating film is dried, or the coating film is cured
.

The coating (or wet coating film) applied on the surface of the object to be coated is cured into a solid, continuous dry coating film to achieve the purpose of coating
.

No matter what kind of painting, these three contents are included
.
For the coated objects with special requirements, some other processes are sometimes added, such as the surface coating of the car body.
After the coating is dried, the coating film is sometimes repaired and maintained, and the protective wax is applied
.