As the demand for sustainable, high-performance additives in polymer processing continues to grow, DHT-4—a synthetic hydrotalcite compound—has emerged as a key material in thermal stabilization and acid scavenging systems. Produced by Kisuma Americas, a global leader in magnesium-based and hydrotalcite additives, DHT-4 is engineered to deliver superior performance in PVC, polyolefin, and halogen-free flame retardant (HFFR) applications.
This article explores the chemical composition, functional benefits, and industry-specific use cases of DHT-4, highlighting how it enables safer, more efficient, and regulatory-compliant production across a variety of manufacturing sectors.
What is DHT-4?
DHT-4 is a synthetic hydrotalcite, also known as a layered double hydroxide (LDH), composed primarily of magnesium and aluminum hydroxides with carbonate ions intercalated in the interlayer structure. It follows the general LDH formula.
The distinguishing features of DHT-4 include:
- High Mg:Al molar ratio (typically 3:1 or 2:1)
- High purity (low heavy metal and sulfate content)
- Narrow particle size distribution for excellent dispersion
- High anion exchange capacity and thermal stability
Chemical and Functional Properties
DHT-4’s lamellar (layered) structure and ion-exchange behavior allow it to perform several critical roles in polymer stabilization systems:
a. Acid Scavenging
DHT-4 effectively neutralizes hydrogen chloride (HCl) released during thermal degradation of PVC, preventing autocatalytic degradation and preserving polymer integrity.
b. Thermal Stabilization
It enhances long-term heat stability in halogenated polymers by buffering pH changes and absorbing acidic gases during processing or aging.
c. Synergistic Stabilization
DHT-4 acts synergistically with metal stearates (e.g., calcium-zinc or magnesium-zinc) in PVC, improving both initial color stability and long-term thermal resistance.
d. Non-toxic and Halogen-Free
Being free from heavy metals, DHT-4 is environmentally safe and compliant with REACH, RoHS, and FDA requirements for use in sensitive applications like food packaging and medical plastics.
Industrial Applications of DHT-4
a. Rigid and Flexible PVC Compounds
In PVC processing, DHT-4 is widely used as a co-stabilizer in wire and cable insulation, pipe extrusion, profiles, and injection molding. It supports:
- Long-term color retention,
- Reduction in zinc and tin stabilizer loadings,
- Enhanced weatherability and mechanical properties.
b. Halogen-Free Flame Retardant (HFFR) Compounds
In combination with magnesium hydroxide (Mg(OH)₂) or aluminum trihydrate (ATH), DHT-4 contributes to the flame retardancy of polyolefin formulations by:
- Suppressing smoke production,
- Enhancing char formation,
- Improving thermal barrier performance.
c. Polyolefin and Polyamide Systems
Used in filled and reinforced formulations, DHT-4 serves as:
- An acid acceptor for polyamide (nylon) processing,
- A processing stabilizer in regrind and recycled plastics.
d. Environmental and Regulatory Applications
DHT-4 is used in food-contact and medical-grade polymers, thanks to its inertness, safety profile, and ability to meet stringent migration and toxicity standards.
Kisuma Americas: The Global Leader in DHT-4 Production
Kisuma Americas, a subsidiary of Japan’s Kyowa Chemical Industry, is the largest and most advanced producer of hydrotalcite additives in the Western Hemisphere. Their Texas-based manufacturing plant ensures consistent quality, regulatory compliance, and secure supply for North American manufacturers.
Why Kisuma’s DHT-4 Stands Out:
- Unmatched Purity: Produced using proprietary synthesis technology, Kisuma’s DHT-4 features low levels of trace contaminants and optimized surface chemistry.
- Controlled Morphology: Tailored particle size and morphology ensure superior dispersibility and compatibility with polymer matrices.
- Regulatory Approval: DHT-4 is certified under FDA 21 CFR and conforms to EU food-contact regulations, making it ideal for high-integrity packaging and consumer products.
- Technical Support: Kisuma provides detailed application guidance, compatibility analysis, and co-formulation recommendations to help manufacturers optimize formulations.
- Sustainability Focus: DHT-4 is non-toxic, halogen-free, and supports environmental goals in green building materials and low-emission plastics.
As environmental regulations tighten and industries push for safer, more efficient materials, DHT-4 stands as a cornerstone additive for modern polymer systems. Its multifunctional roles as an acid scavenger, thermal stabilizer, and synergistic co-additive offer significant performance and sustainability benefits across a wide spectrum of industrial applications.
With Kisuma Americas leading innovation and manufacturing excellence in hydrotalcite chemistry, DHT-4 continues to set the standard for what a high-performance additive can deliver in terms of functionality, regulatory compliance, and supply reliability.
