Unlock the secrets of using paint adhesion promoters to create high-quality coatings
In the manufacturing of various products, the paint process can give products a bright appearance and
excellent protective performance, but the adhesion problem between the paint and the substrate is often a
headache. At this time, the paint adhesion promoter is like a "secret weapon" that can greatly improve the
adhesion of the paint. However, to give full play to its role, correct use is crucial. The following is a detailed
introduction to the use of paint adhesion promoters.
Preliminary preparation: Lay a good foundation for use
Substrate cleaning treatment
Before using the adhesion promoter, you must ensure that the surface of the substrate is clean and free of
impurities. Just like laying the foundation for a house, if the surface of the substrate is not well treated, the
subsequent coating will be difficult to adhere firmly. For metal substrates, remove the oil, rust and oxide layer
on the surface. You can use sandpaper to polish to remove rust and oxide layers, and then wipe with organic
solvents such as acetone and alcohol to remove oil and dust. There may be mold release agent residues on the
surface of the plastic substrate. It should be cleaned with a special cleaning agent, then rinsed with clean water
and dried. Composite substrates should use appropriate cleaning methods according to their material
characteristics to remove surface contaminants.
Environmental conditions control
The effect of adhesion promoter is greatly affected by ambient temperature and humidity. Generally speaking,
the suitable use temperature is between 15℃ - 30℃, and the humidity is more suitable between 40% - 70%. If
the temperature is too low, the drying and reaction speed of adhesion promoter will slow down, affecting the
use effect; if the temperature is too high, the promoter may evaporate too quickly, resulting in uneven coating.
If the humidity is too high, moisture may remain on the surface of the substrate or in the promoter, affecting
adhesion; if the humidity is too low, the promoter may dry too quickly and fail to fully react with the substrate
and paint. Therefore, before use, check the weather forecast or use a thermometer and hygrometer to detect
environmental conditions. If they do not meet the requirements, you can take measures such as heating,
dehumidification or cooling, humidification, etc. to adjust.
Construction operation: precise execution of steps
Dilution and preparation
The dilution ratio of adhesion promoters of different brands and models may be different. Be sure to read the
product manual carefully before use. When diluting, use the matching diluent and mix the promoter and diluent
evenly according to the specified ratio. For example, some accelerators may need to be diluted with specific ester
or ketone diluents, and the dilution ratio may be 1:1 or 1:2. During the mixing process, stir slowly to avoid bubbles.
The stirring time is generally 3-5 minutes to ensure that the accelerator and diluent are fully blended.
Selection of brushing method
There are many ways to apply adhesion promoters, the most common of which are spraying, brushing and dipping.
Spraying has high efficiency and uniform coating, which is suitable for the construction of large-area substrates, but
requires professional spraying equipment and operating skills. Brushing is simple to operate and low in cost. It is
suitable for small areas or complex-shaped substrates, but attention should be paid to brushing evenly to avoid brush
marks and missing coating. Dipping is to immerse the substrate in the adhesion promoter. It is suitable for small or
regular-shaped substrates and can ensure full coverage of the substrate surface. When choosing a brushing method,
it is necessary to consider the shape, size and construction conditions of the substrate.
Coating thickness and drying time control
Coating thickness has a great influence on the effect of adhesion promoters. If the coating is too thin, it may not form
enough active layer, affecting the adhesion between the paint and the substrate; if the coating is too thick, it will not
only increase the cost, but also may extend the drying time and even cause problems such as cracking of the coating.
Generally speaking, it is more appropriate to control the coating thickness between 5 and 15 microns. The coating
thickness can be controlled by adjusting the number of brushing, dilution ratio or using a professional coating thickness
gauge.
After brushing, give enough drying time. Drying time is affected by factors such as ambient temperature, humidity
and coating thickness. Under suitable environmental conditions, the general drying time is 10 to 30 minutes. During
the drying process, avoid dust, debris, etc. falling on the surface of the coating to affect the drying effect. You can use a
clean gauze or plastic film to gently cover the coating for protection.
Paint coordination: synergistic effect
Paint construction time interval
After the adhesion promoter is dry, paint construction should be carried out in time. If the time interval is too long, the
adhesion promoter surface may absorb dust and impurities, affecting the combination with the paint; if the time interval
is too short, the adhesion promoter may not be completely dry and reacted, which will also reduce the adhesion. Generally
speaking, it is more appropriate to apply the paint within 1-2 hours after the adhesion promoter dries. If the application
cannot be carried out in time due to special circumstances, the substrate should be sealed with a clean plastic film to
avoid contamination.
Adjustment of paint process
After using the adhesion promoter, the construction process of the paint may also need to be adjusted appropriately.
For example, the viscosity of the paint, the spraying pressure, the drying temperature and time. The adhesion promoter
may change the chemical properties and physical structure of the substrate surface, making the paint easier to adhere
and flow. Therefore, the viscosity of the paint should be adjusted according to the actual situation. Generally, the viscosity
can be appropriately reduced to improve the leveling of the paint. The spraying pressure should also be adjusted according
to the coating thickness and the characteristics of the paint to ensure that the paint is evenly covered on the surface of the
substrate. The drying temperature and time should be set according to the matching requirements of the adhesion promoter
and the paint. Generally, the drying temperature can be reduced by 5℃-10℃ compared to when the promoter is not used,
and the drying time can be appropriately extended by 10%-20% to ensure that the paint is fully dried and cured.
Post-inspection and maintenance: guarantee the use effect
Adhesion test
After the paint is applied, the adhesion of the coating should be tested. Commonly used detection methods include the
grid method and the pull-off method. The grid method is to use a knife to draw a certain size of grid on the surface of the
coating, and then stick the tape on the grid, quickly tear off the tape, and observe the shedding of the coating. If the coating
shedding area is less than 5%, the adhesion is qualified. The pull-off method is to use a special pull-off tester to pull the coating
from the substrate and measure the force required for pulling. The greater the force, the better the adhesion. If the test finds that
the adhesion is unqualified, the cause should be analyzed in time. It may be due to improper use of adhesion promoter, problems
with the paint process, or incomplete substrate treatment, and then take corresponding remedial measures, such as re-applying
adhesion promoter, adjusting the paint process, or re-processing the substrate.
Daily maintenance suggestions
During the use of the product, pay attention to the maintenance of the paint coating. Avoid collision and scratching with sharp
objects to prevent damage to the coating. For some occasions where chemicals may be exposed, the contact time between chemicals
and coatings should be minimized. If contact occurs, rinse with clean water in time. Check the appearance of the coating regularly.
If peeling, flaking, discoloration, etc. are found, repair them in time to ensure the beauty and service life of the product.
Correct use of paint adhesion promoter is the key to creating high-quality paint coatings. From preliminary preparation, construction
operation to paint coordination and later inspection and maintenance, every link must be taken seriously. Only in this way can the role
of adhesion promoter be fully utilized to give the product a beautiful and durable paint coating.
