AB adhesive defoamer usage guide: full process operation analysis of precise defoaming
In the application process of AB glue, the problem of bubbles has always been a major challenge affecting
product quality. As the core additive for solving this problem, the use of AB adhesive defoamer directly affects
the defoaming effect and final product performance. From the preparation work before use, to the specific
operation process, and to the precautions during use, every link needs to be precisely controlled. Next, we
will systematically introduce the correct usage method of AB adhesive defoamer.
1、 Preparation before use
（1） Clarify the characteristics and application scenarios of AB adhesive
Different types of AB adhesives have different characteristics such as composition, viscosity, curing speed, and
require different defoamers. For example, epoxy resin based AB adhesives have high viscosity and are difficult to
release bubbles, so it is necessary to choose defoamers with strong defoaming ability and good dispersibility; And
acrylic AB adhesive has a fast curing speed, requiring defoamers to quickly exert their effect and avoid residual bubbles
before curing. At the same time, according to the application scenarios of AB glue, such as electronic packaging, building
bonding, and handicraft production, there is also a focus on the performance requirements of defoamers. The field of
electronic packaging requires defoamers with good electrical insulation properties; Food contact related scenarios require
defoamers to meet food grade safety standards. Therefore, before use, it is necessary to fully understand the characteristics
and application scenarios of AB glue, laying the foundation for selecting suitable defoamers.
（2） Choose an appropriate defoamer
At present, there are various types of AB adhesive defoamers on the market, mainly including organosilicon, polyether,
mineral oil, etc. Organic silicone defoamers have high defoaming efficiency and long-lasting foam inhibition, and are suitable
for AB adhesives in various systems. However, they may cause adverse reactions to certain sensitive materials; Polyether
defoamers exhibit stability in high temperature and strong alkaline environments, and have good adaptability to water-based
AB adhesives; Mineral oil defoamers have good compatibility and relatively low prices, making them suitable for cost sensitive
application scenarios. When selecting defoamers, in addition to considering the type, attention should also be paid to the
technical parameters of the product, such as active ingredient content, pH value, density, etc. Through sample testing, the
defoaming effect, compatibility, and impact on curing performance of different defoamers in actual AB adhesive systems
should be compared, and the most suitable product should be determined.
（3） Determine a reasonable amount of addition
The amount of AB defoamer added is not necessarily better, excessive use may lead to problems such as shrinkage and surface
defects in AB glue, while also increasing costs; If the dosage is insufficient, the ideal defoaming effect cannot be achieved.
Generally speaking, the amount of AB adhesive defoamer added ranges from 0.1% to 1% (based on the total mass of AB adhesive),
but the specific value needs to be adjusted according to the characteristics of AB adhesive, the severity of bubbles, and the
performance of the defoamer. In actual production, the gradient test method is usually used to determine the optimal addition
amount. Prepare a series of AB adhesive samples containing different amounts of defoamers, observe their defoaming effect,
surface state after curing, and performance indicators, and select the addition amount that can completely eliminate bubbles
without affecting other properties of AB adhesive as the production standard.
2、 The usage process of AB adhesive defoamer
（1） Pre dispersion treatment (for some defoamers)
For some solid or high viscosity AB adhesive defoamers, pre dispersion treatment is required before use to ensure that they
can be uniformly dispersed in the AB adhesive. For example, after grinding the solid defoamer into fine powder, it is thoroughly
mixed with a small amount of component A or B of AB glue under low-speed stirring to form a pre dispersion; For high viscosity
liquid defoamers, an appropriate amount of diluent (such as solvent for AB glue) can be used to dilute and stir evenly before use.
Pre dispersion treatment can improve the dispersion efficiency of defoamers in AB glue and enhance the defoaming effect.
（2） Add defoamer
Add defoamers before or during the mixing process of AB glue. If the mixing ratio of AB glue is 1:1, defoamers can be added to
component A or component B in advance, stirred evenly, and then mixed with another component; If the mixing ratio of AB glue
is different, the defoamer can be added to the component with a larger proportion according to the actual situation, or
components A and B can be added separately. When adding, the defoamer should be slowly and evenly added to avoid excessive
concentration in the local area caused by a large amount of addition at once, which affects the defoaming effect and the uniformity
of AB glue. Meanwhile, maintain an appropriate stirring speed during the addition process to enable the defoamer to quickly
disperse in the AB gel.
（3） Mixing and defoaming operations
After adding defoamer, it is necessary to stir thoroughly to ensure that the defoamer is completely mixed with AB glue. The
stirring speed should not be too fast to avoid introducing new bubbles, generally controlled at 100-300 revolutions per minute.
The stirring time depends on the amount and viscosity of the AB glue, usually 3-10 minutes, until a significant reduction or
disappearance of bubbles in the AB glue is observed. For some application scenarios with extremely high requirements for
bubbles, such as precision electronic packaging, residual bubbles can be further removed by vacuum degassing after stirring.
Put the mixed AB glue into a vacuum defoamer, set the appropriate vacuum degree and defoaming time (such as vacuum
degree -0.08MPa, time 5-10 minutes), so that the bubbles in the AB glue can be quickly expelled under negative pressure
environment.
（4） Observation and verification
After completing the defoaming operation, it is necessary to observe and verify the AB adhesive. Firstly, visually inspect the
surface of AB adhesive for flatness, smoothness, and the presence of residual bubbles or pores; Then, a small sample test is
conducted to cure the processed AB adhesive, and key indicators such as bonding strength and electrical performance are
tested to ensure that the use of defoamers does not have a negative impact on the performance of the AB adhesive.
If bubble problems or abnormal performance are still found, it is necessary to analyze the cause, adjust the amount and
method of adding defoamer, or replace the type of defoamer, and perform the defoaming operation again.
3、 Precautions during use
（1） Temperature and environmental control
The performance of AB adhesive defoamer is greatly affected by temperature. Most defoamers can only achieve their best effect
within a certain temperature range, and excessively high temperatures may cause the effective components in the defoamer to
evaporate or decompose, reducing its defoaming ability; If the temperature is too low, the activity of the defoamer will decrease
and the defoaming speed will slow down. Therefore, when using AB adhesive defoamer, the ambient temperature and AB
adhesive temperature should be controlled within an appropriate range, generally between 20 ℃ and 30 ℃. At the same time,
keep the operating environment clean to avoid dust, impurities, etc. from entering the AB glue and introducing new bubbles.
（2） Compatibility with other additives
In the formula of AB glue, in addition to defoamers, other additives such as curing agents, toughening agents, fillers, etc. may
also be added. These additives may interact with each other, affecting the effectiveness of defoamers or the performance of AB
adhesives. For example, certain curing agents may react chemically with defoamers, leading to their failure; The addition of
toughening agents may alter the viscosity of AB glue and affect the dispersibility of defoamers. Therefore, before using defoamers,
compatibility testing of additives is required. Mix the defoamer with other additives according to the actual production ratio,
observe whether there are precipitation, layering, discoloration and other phenomena, and conduct a small sample curing test to
check whether the performance of AB adhesive is normal. If compatibility issues are found, the type, dosage, or order of additives
can be adjusted, and if necessary, a combination of additives with synergistic effects can be selected.
（3） Safety and Storage
Some AB adhesive defoamers may have certain toxicity, irritation, or flammability, and safety precautions must be taken during
use. Operators should wear protective gloves, masks, goggles and other protective equipment to avoid contact between
defoamers and skin or eyes. If accidentally touched, rinse immediately with plenty of water and seek medical attention promptly.
At the same time, AB adhesive defoamers should be stored in a cool, ventilated, and dry environment, away from sources of fire
and oxidants, to prevent safety accidents such as fires and explosions. Pay attention to checking the shelf life of the defoamer
and avoid using expired products that may affect the defoaming effect and AB adhesive quality.
The correct use of AB adhesive defoamer is a key step in ensuring the quality of AB adhesive products. By fully preparing
before use, following standardized operating procedures, and strictly controlling precautions, it is possible to effectively eliminate
bubbles in AB glue and improve the appearance and performance of the product. With the continuous expansion of AB adhesive
application fields and the increasing demand for product quality, mastering the scientific use of defoamers will bring greater
value to production and application.
