A practical guide to using viscosity reducing dispersants
A practical guide to using viscosity reducing dispersants
As an important auxiliary agent in the chemical industry, viscosity reducing dispersants can effectively improve material properties, but improper use not only fails to achieve the expected effect, but may also cause a series of problems. In order to make viscosity reducing dispersants fully play their role in various industries, it is crucial to master scientific and reasonable methods of use. Next, I will share some practical usage suggestions with you.
1. Accurate selection and adaptation to system characteristics
Different types of viscosity reducing dispersants have different applicable scenarios due to differences in structure and properties. When choosing, we must first clarify the properties of the system to be used, including the acidity, polarity, and temperature requirements of the system. For example, anionic viscosity reducing dispersants have good dispersion effects in alkaline or neutral systems and are often used in water-based coatings, papermaking and other industries; cationic viscosity reducing dispersants perform well in acidic environments and are suitable for certain acid dye systems or oilfield acidification operations; non-ionic viscosity reducing dispersants have good temperature resistance and water resistance, and are widely used in plastic processing, building materials and other fields under high temperature or high humidity environments. In addition, the characteristics of the dispersed material should also be considered. If inorganic pigments are to be dispersed, a viscosity-reducing dispersant with strong affinity for inorganic particles should be selected; for organic pigments or polymer particles, products with good compatibility should be selected. Before actual application, it is best to conduct a small test to determine the most suitable product by comparing the dispersion effect and viscosity reduction degree of different types of viscosity-reducing dispersants.
2. Control the dosage to avoid excessive or insufficient use.
The dosage of viscosity-reducing dispersants is not the more the better. Excessive use may cause system performance degradation or even negative effects. Generally speaking, the amount of viscosity-reducing dispersants added needs to be adjusted according to the specific conditions of the system, such as solid particle content, particle size, and liquid medium viscosity. In the coatings industry, the amount of viscosity-reducing dispersants added is usually 0.5% - 3% of the total amount of pigments and fillers; in plastic filling modification, the amount added may be between 0.2% - 1%. When determining the dosage, you can start from a lower amount and gradually increase it, observe the changes in system viscosity and dispersion effect, and find the best dosage balance point. At the same time, it should be noted that the effective ingredient content and activity of viscosity-reducing dispersants produced by different manufacturers are different. The fixed ratio cannot be completely copied. The accurate dosage must be determined in combination with the product manual and actual tests.
3. Optimize the addition method to ensure uniform dispersion
The addition method has an important impact on the effect of the viscosity-reducing dispersant. In order to make the viscosity-reducing dispersant fully play its role, it should be ensured to be evenly dispersed in the system as much as possible. Common addition methods include pre-dispersion method and direct addition method. The pre-dispersion method is suitable for systems with high solid particle content and greater dispersion difficulty. The viscosity-reducing dispersant is mixed with a small amount of liquid medium, stirred evenly to form a pre-dispersion liquid, and then the pre-dispersion liquid is added to the entire system for full stirring; the direct addition method is to slowly add the viscosity-reducing dispersant during the system stirring process. This method is simple to operate, but it should be noted that the addition speed should not be too fast to avoid excessive local concentration. In addition, the order of addition is also worth paying attention to. In some complex systems, the viscosity-reducing dispersant should be added first, and then other additives and ingredients should be added after it fully reacts with the solid particles to achieve a better dispersion effect.
4.pay attention to the use environment to ensure the best effect
The performance of viscosity-reducing dispersants will be affected by environmental factors such as temperature and pH value. Excessively high temperature may cause some viscosity-reducing dispersants to decompose or lose their activity. For example, some viscosity-reducing dispersants containing thermosensitive groups may degrade at high temperatures, resulting in a decrease in the viscosity-reducing dispersion effect; too low temperature may affect the diffusion rate of the viscosity-reducing dispersant in the system and the adsorption effect on the particles. Therefore, it is necessary to control the appropriate use temperature according to the characteristics of the viscosity-reducing dispersant and the system requirements. Generally speaking, most viscosity-reducing dispersants can work well in an environment of room temperature to about 60°C. The pH value will also affect the ionization degree and stability of the viscosity-reducing dispersant. For example, anionic viscosity-reducing dispersants are more stable in alkaline environments, and cationic viscosity-reducing dispersants perform better in acidic environments. When using, ensure that the pH value of the system is within the applicable range of the viscosity-reducing dispersant.
5. do a good job of storage management to prevent performance failure.
The storage conditions of viscosity-reducing dispersants are also critical. Most viscosity-reducing dispersants should be stored in a cool, dry, and ventilated environment, avoiding direct sunlight and high temperature and humidity. Some viscosity-reducing dispersants have requirements for the material of the storage container. For example, some viscosity-reducing dispersants containing strong acidic or alkaline components cannot be stored in metal containers to avoid chemical reactions that affect product performance; viscosity-reducing dispersants containing organic solvents should be kept away from fire sources to prevent fire and explosion hazards. At the same time, attention should be paid to the shelf life of the product. Expired viscosity-reducing dispersants may deteriorate or fail. Before use, the appearance and performance of the product should be carefully checked to ensure its quality.
The use of viscosity-reducing dispersants is a task that requires comprehensive consideration of many factors. Through accurate selection, reasonable control of dosage, optimization of addition methods, attention to the use environment and good storage management, viscosity-reducing dispersants can be used to their maximum effectiveness in different fields, bringing more convenience and benefits to production and life.