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Chain Extenders
Chain extenders are essential components in polyurethane (PU) and polyurea formulations, directly influencing the cured polymer’s final mechanical, thermal, and chemical performance. In polyurethane chemistry, chain extenders react with isocyanate groups to build molecular weight and increase crosslink density, thus improving hardness, strength, and thermal resistance.
Dorf Ketal‘s Unilink® and Clearlink® product lines offer a comprehensive selection of high-performance chain extenders based on secondary diamines. These compounds are engineered explicitly for polyurea coatings, cast elastomers, and hybrid polyurethane-urea systems. They offer formulators superior control over–reactivity and cure kinetics compared to conventional primary amines or diols.
One of the most important features of Unilink® chain extenders is their controlled reactivity. Secondary diamines are inherently slower to react with isocyanates than primary amines, providing formulators with longer pot life and more processing flexibility. This is critical in applications such as spray polyurea coatings and two-component elastomer systems, where working time must be balanced with cure speed and throughput.

Unilink® and Clearlink® Solutions
Controlled Reactivity for Extended Pot Life
Controlled Reactivity for Extended Pot Life
High Hardness and Fast Cure for Elastomers
High Hardness and Fast Cure for Elastomers
Improved UV Stability and Flexibility
Improved UV Stability and Flexibility
Low-VOC, Solvent-Free Formulations
Low-VOC, Solvent-Free Formulations
Tunable Mechanical Properties
Tunable Mechanical Properties
Robust Performance in Protective Coatings
Robust Performance in Protective Coatings
Smart Reactivity
Smart Reactivity
- Aromatic diamines offer fast reactivity and high hardness, making them ideal for demanding applications such as truck bed liners, structural elastomers, and industrial flooring.
- Aliphatic diamines react more slowly, resulting in enhanced flexibility, UV stability, and longer gel times—features particularly valuable in coatings and outdoor exposure applications.
The ability to fine-tune hardness (e.g., Shore A/B), tensile strength, elongation, and chemical resistance makes these products a core component of high-performance polyurea and PU formulations.
In polyurea coatings, Unilink® and Clearlink® chain extenders contribute to the formulation of protective systems with outstanding impact resistance, abrasion durability, and weatherability. Common end uses include corrosion protection on steel and concrete, waterproofing membranes, bridge decks, and containment structures. Their compatibility with various polyols and isocyanates—both aromatic and aliphatic—makes them ideal for a wide range of design spaces.
Moreover, these chain extenders are particularly useful in formulating low-VOC, solvent-free systems, supporting sustainability initiatives, and regulatory compliance across North America and globally. Dorf Ketal's Unilink® portfolio empowers formulators to go beyond traditional performance boundaries—offering durable, tunable, and efficient solutions in advanced polyurethane and polyurea technologies.
Recommended Products
Subcategory/Type
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Primary Products
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Aliphatic Diamines
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Clearlink 1000, Clearlink 1080
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Aromatic Diamines
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Unilink 4200, Unilink, Unilink 4230, 4100
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Titanium based
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Unilink 2000 Series
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Zirconion based
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Unilink 1000 Series
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