DHT-4A and DHT-4V
DHT-4A® is the flagship product of Kisuma Chemicals' branded range of hydrotalcite-like materials that have been developed specifically for irreversible acid scavenging in polymer production and processing systems. Already for more than 30 years, DHT-4A® is considered to be the industry standard for deactivation of catalyst residues in polyolefins. The product is environmentally harmless and is generally acknowledged to be the best of its kind. This is reflected by the fact that DHT-4A® is on the approval list of practically all polyolefin technology providers globally.
Designed for Performance
The superiority of DHT-4A® as compared to other products results from its particular mechanism of adsorbing acids based on anion exchange. In the presence of acidic substances such as chloride ions, DHT-4A® will exchange the carbonate ions from the interlayer of its crystal structure and replace them with the chloride ions, which are rendered harmless.
Advantages of DHT-4A®
Compared to alternative additives, such as Calcium Stearate (Ca-St), DHT-4A® superior for the following reasons:
- DHT-4A® can adsorb anions equivalent to about 10% of its own weight. The significantly higher capacity compared to alternatives minimizes the loss of physical properties of polymers.
- With DHT-4A®, superior haze, gloss and transparancy properties can be achieved.
- By using DHT-4A®, stearic acid vapors can be eliminated.
- With DHT-4A®, the amount of water carry-over is significantly less than with Ca-St.
DHT-4A® is a highly pure and uniform powder that has a sub-micron particle size. Our proprietary technology ensures a consistently narrow particle size distribution. After synthesis, the particles are treated with a surface active agent to increase their affinity with polymers. Consequently, DHT-4A® has excellent dispersion properties which makes the product suitable for a wide range of applications, including but certainly not limited to:
- Deactivation of residual acidic substances that originate from catalytic polymerization processes used to produce polyolefins and comparable polymers and elastomers. Using DHT-4A® will significantly reduce corrosion damage of process equipment and of the polymer itself.
- Scavenging free halogen ions deriving from radicals in halogenated flame retardants in various polymers.
- Rendering acidic residues in engineering plastic inert in order to prevent corrosion damage of molding equipment.
- Acid acceptor in halogenated rubber, when high water resistance is required.
- Corrosion inhibition in polymer-based coating systems and adhesives, which increases protection of metallic surfaces against corrosive anions.
- Long term weatherability in combination with Hindered Amine Light Stabilizers (HALS).
Alternative Product Grades
Our experience with the implementation of DHT-4A® in a wide range of applications, has resulted in the development of a variety of alternative products that may fit your specific needs.
- DHT-4A®: The industry standard acid scavenger.
- DHT-4V: Similar to DHT-4A but with a vegetable based surface active agent, instead of tallow.
- DHT-4A-2: Dehydrated grade for higher thermal stability (> 180 degrees Celsius).
- DHT-4C: Hydrophilic and calcined grade for higher thermal stability (>300 degrees Celsius).
- ZHT-4V: Product in which Zinc has been incorporated for improved color.
- KW2200: Hydrophilic and highly calcined grade (magnesium aluminium oxide).
Your Innovation Partner
Having trouble to determine the appropriate grade for your product? Or do you have your own ideas for product improvements? Contact our Marketing and Sales department to get in touch with one of our product managers.