Defoamer factory types of defoamer agents and their defoaming principles

 

 

How to choose defoamer factory

Generally speaking, the following points should be considered when choosing a defoamer manufacturer:

1. Product quality: First of all, you need to consider whether the defoaming agent factory ‘s product quality meets your requirements. You can check whether the manufacturer has relevant quality certifications and whether there are feedback from other customers.

2. After-sales service: Good after-sales service can help you solve problems encountered during use and provide necessary technical support.

3. Price: Price is also one of the factors to consider. Of course, it is not that the lower the price, the better, but the cost-effectiveness needs to be considered comprehensively.

 

Classification provided by defoamer factory

Defoaming agents are currently mainly divided into three categories based on ingredients: silicone, mineral oil, and polyether defoaming agents. Based on the form, they are divided into liquid and powder defoaming agents.

The mechanism of action of defoaming agents is analyzed based on the classification of defoaming agents. This article focuses on analyzing the types of defoaming agents, their performance characteristics and application fields.

1. Silicone defoamer

Silicone defoaming agents from our defamer factory have strong defoaming ability, average foam suppression ability, poor solubility, and fast defoaming speed at room temperature, but are prone to stratification at high temperatures, poor foam suppression, and slow defoaming speed. .

Silicone defoaming agents generally include polydimethylsiloxane, etc. Because of its low cost and fast defoaming, silicone defoaming agents are widely used in various fields of industrial production and are currently the mainstream defoaming agent products.

2. Polyether defoaming agent

The defoaming ability of polyether defoaming agents is relatively poor compared to silicone defoaming agents, but the foam suppressing ability is relatively strong. The foam suppressing time is long, the effect is good, and the thermal stability is good. Therefore, it is widely used in industrial cleaning and high-temperature operations.

The polyether-modified silicone defoamer has the advantages of both polyether and silicone defoamer, and is currently a mainstream development direction of defoamer.

The main ingredients of polyether defoaming agents generally include polyoxypropylene, glycerin, ether ethylene oxide, etc.
Generally, it is added in food products such as soy products, beverages, sucrose and other production processes, and in industrial production such as papermaking, circuit board cleaning, cement mortar, coating and ink, power plant desulfurization and other fields, it has also been widely used to suppress foam. application.

3. Mineral oil defoaming agent

Mineral oil defoaming agents are usually composed of active agents and carriers. The carriers are mainly low surface tension substances. Water, fatty alcohols, etc. are relatively common carriers. They mainly play a carrying and diluting role, while the active agents are responsible for inhibiting Commonly used active agents such as fats, waxes, and fatty amides play a major role in eliminating foam.

 

1. The generation of bubbles in paint and the principle of foam stabilization

During the production process of paint, air will be involved to form bubbles. Certain raw materials in the paint, such as surfactants and dispersants, will stabilize the bubbles.

Bubbles can also be produced during the application of paint, which mainly depends on how the paint is applied. For example: Curtain coating can continuously entrain air into the paint, and airless spraying can also easily entrain air. Spraying under relatively low humidity conditions or under high temperature conditions can easily generate bubbles.

Principle of bubble stabilization:

Marangoni effect (liquid backflow caused by surfactants, counteracting the effect of gravity)

 

 

Electrostatic effect: The electrostatic repulsion of surfactants thickens the liquid film of the bubbles, thus stabilizing the bubbles.

2. Function principle of defoaming agent

Defoaming agents work during or after the foam thin layer formation stage:

The evenly dispersed defoaming agent penetrates into the foam elastic film and is distributed in the film, causing the thin layer to rupture through the reduction of surface tension.

The evenly dispersed defoaming agent penetrates into the foam thin layer and forms a monomolecular film, which reduces its adhesion and makes the thin layer prone to rupture.

Defoamer containing hydrophobic particles has a third mechanism. These hydrophobic particles reach the surface of the thin layer and adsorb surfactant on the top of the thin layer. The thin layer breaks due to lack of surfactant.

3. Selection and evaluation methods of defoaming agents
The defoaming agent must be able to spread quickly on the foam surface and penetrate quickly to cause the foam to burst quickly. The commonly used types of defoaming agents currently include silicones and polyacrylates.

Silicone defoamers are usually of the polysiloxane type. For example: polydimethylsiloxane containing acrylate functional groups and polyether-modified polydimethylsiloxane. Organosilicon has high temperature resistance, low temperature resistance, stable physical properties, chemical inertness, and very low surface tension, and is a commonly used defoaming agent.

Defoaming from our defamer factory such as polyacrylic acid defoam by changing the polarity and molecular weight of the polymer to cause selective incompatibility. The impact on gloss needs to be evaluated when using such defoaming agents.

When selecting a suitable defoaming agent in the future, the process of foam generation in the system, the compatibility and concentration of the system, temperature and viscosity, etc. must be taken into consideration. Each of the above factors will have a direct impact on defoaming agent selection.

The following aspects should be considered when evaluating foam control agents: spreading rate; compatibility with the system; defoaming stability and cost performance. However, the above factors are often contradictory in a formula. For example, the defoaming agent that is compatible with the system often has the worst defoaming stability; the one with the worst compatibility often has the fastest spreading rate.

Due to the diversity of coating raw materials and construction methods, defoaming agents need to be evaluated based on actual conditions.

1. Add the defoaming agent to be compared into the varnish according to a certain proportion, put it in a glass bottle, vibrate it in a vibrator for 5 minutes, and take it out for observation. Preliminarily determine the defoaming ability of the defoaming agent based on the amount of foam. ; After leaving it for 10 minutes/30 minutes, observe the height of the foam again and compare the defoaming speed;

2. Use a scraper fineness meter to scrape the paint liquid to determine the compatibility of the defoaming agent and the system (whether there are shrinkage cavities);

3. After the system foam is eliminated, observe the clarity of the system to see if there are turbidity, stratification, oil slicks, etc.;

4. Storage stability: After leaving it for half a month, repeat the experiment in steps 1, 2, and 3 to determine the long-term effectiveness of the defoaming agent.

5. Determine the amount to add.

 

Precautions when using defoamer

Select factors to consider
The physical and chemical properties of an ideal defoaming agent must meet the requirements of the system in which it is used. Generally speaking, the following requirements must be considered when selecting a defoamer:

(1) It has strong defoaming ability and can effectively eliminate foam when using a very small amount;

(2) Has a lower surface tension than the system being defoamed;

(3) The addition of defoaming agent will not affect the basic performance of the system being defoamed;

(4) Insoluble in the system being defoamed and not easily solubilized by surfactants in the system;

(5) The surface tension balance should be good;

(6) It does not react with the medium to be defoamed, nor will it be decomposed or degraded by it, and has good chemical stability;

(7) It has good diffusivity and permeability, has a positive diffusion coefficient in the foam medium, and has the ability to spread quickly on the foam surface;

(8) Good heat resistance and will not lose effectiveness at high temperatures;

(9) Has good gas solubility and permeability;

(10) It has high physiological activity and safety in the system to be defoamed, and the defoaming agent itself is a non-toxic or low-toxic substance;

(11) Have low chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total oxygen demand (TOD);

(12) Has good storage stability;

(13) It has a long-term defoaming effect. Some defoaming agents can defoam quickly, but they will lose effectiveness over time;

(14) Low cost;

(15) Does not increase the surface viscosity of surfactant aqueous solution.

It is difficult for defoaming agents to meet the above requirements at the same time and can only meet the requirements of the system being defoamed in terms of main performance. Each defoaming agent can only be effective for a certain system or several systems. A variety of different defoaming agents can also be used for the same foam system. Because of this, users should conduct experiments and choose the most effective and economical one. Defoaming agent.

Turbidity problem
The main components of defoaming agents are generally hydrophobic particles, silicone oil and emulsifiers. The hydrophobic particles absorb silicone oil so that the silicone can achieve the maximum effect with as little as possible. As the main defoaming medium, silicone oil has a very small surface tension and is neither lipophilic nor hydrophilic. It is suspended in the system. When the defoaming agent exists in the middle of the foam wall, it repels the oil and water phases to produce a defoaming effect. At the same time, there is a small amount of silicone oil. Consumption, when the silicone oil outside the hydrophobic particles is completely consumed, causing the foam system to become turbid.

Therefore, the amount and color of hydrophobic particles, silicone oil, and emulsifier used in the defoaming agent are different, resulting in a wide range of defoaming agent performance. When the defoaming agent has a good defoaming effect and a long foam suppression time, turbidity will generally not appear in the system.

Oil drift problem
Since the defoaming agent is not dissolved in the system but dispersed in the system, the uniformity of the dispersion of the defoaming agent in the system is very important.

When the defoaming agent is evenly dispersed in the system, it has little impact on the transparency of the system, and it takes a long time to agglomerate into larger particles and can remain in the system for a long time;

When the defoaming agent is not evenly dispersed in the system, but agglomerates into many small particles, on the one hand it will affect the transparency of the system, and on the other hand it will shorten the time for the defoaming agent to agglomerate into large particles, which results in After the defoaming agent is added to the system, it becomes turbid and the oil becomes bleached the next day.

In order to avoid oil drift, methods that can be adopted include: moving the addition order of defoaming agent forward; diluting it before adding it to the system. The diluent can be water or a surfactant in the system.

Foam suppression time problem
The nature of the silicone oil in the defoaming agent determines the foam suppression time of the defoaming agent. The content of the silicone oil determines the consumption cycle of the defoaming agent in use. If the amount of silicone oil added is too small, the defoaming performance of the defoaming agent will not reach the required value. , adding too much will affect the performance of the defoamer and reduce the defoaming property of the defoamer;

The particle size of the defoamer determines the filtration resistance of the defoamer. If the particle size is too large, the defoamer may be easily filtered and produce floating oil, which may affect foam suppression. The stirring time is also important for the defoamer’s foam suppression ability. Inadequate stirring may cause turbidity, oil drift, weakened defoaming ability, and shortened foam suppression time.

Failure problem
Acid-base stability. Silicone oil can destroy the surface tension of the liquid and eliminate foam. If the defoaming agent has poor acid and alkali resistance, it will cause the decomposition of the silicone oil, resulting in a reduction in defoaming ability or even failure. Adding silicate to the system will generally inhibit its decomposition; Defoaming agent solubility.

Certain chemical components cause silicone oil to dissolve into the system, so that the defoaming agent no longer has a defoaming effect, but exists as a surfactant in the system, and the system foam is higher than without adding a defoaming agent.

 

Generally speaking, the following points should be considered when choosing a defoamer manufacturer:

1. Product quality: First of all, you need to consider whether the manufacturer’s product quality meets your requirements. You can check whether the manufacturer has relevant quality certifications and whether there are feedback from other customers.

2. After-sales service: Good after-sales service can help you solve problems encountered during use and provide necessary technical support.

3. Price: Price is also one of the factors to consider. Of course, it is not that the lower the price, the better, but the cost-effectiveness needs to be considered comprehensively.

 

We at Greatspring have a defoamer factory, which is a professional defoamer factory and strictly implements the ISO09001 product quality management system.

First of all, the defoaming agent adopts intelligent semi-automatic production processes and equipment to ensure product stability and consistency.

Secondly, the selection of raw materials is strictly controlled and only raw materials that meet international quality standards are used to ensure the purity and reliability of the products.

In addition, defoaming agents undergo strict quality testing and acceptance procedures and enjoy good success stories in the market. Whether in industrial production or in daily applications, our defoamer factory demonstrate excellent defoaming effects and foam suppression properties. In general, the quality of our defoamer factory products is very good and can meet the defoaming and foam suppression needs of various scenarios.

If you have need, it’s an honor for you to contact our defoamer factory.