Carbodiimide Crosslinker
CAS Number: 25952-53-8
Carbodiimide crosslinkers contain one or more –N=C=N– functional groups that react selectively with carboxylic acid groups in waterborne dispersions at ambient or mildly elevated temperatures to form stable acylurea covalent bonds, imparting outstanding hydrolytic stability to the crosslinked network. Polycarbodiimide (CAS 25952-53-8) is the predominant commercial grade, offering an aqueous-dispersible, low-toxicity alternative to aziridines and isocyanates for environmentally sensitive applications. These crosslinkers are particularly valued in systems requiring long-term humidity and hydrolysis resistance.
Technical Specifications
| pH | 8.0–10.0 |
| purity | ≥98% |
| appearance | Colorless to pale yellow aqueous dispersion or liquid |
Applications
- Waterborne polyurethane and acrylic coatings for demanding environments
- Automotive waterborne clearcoat and basecoat systems
- Ink and overprint varnish binders requiring chemical resistance
- Waterborne adhesives for packaging and flexible substrates
- Hydrolysis-resistant coatings for medical and electronic devices
Key Features
- Selective and efficient crosslinking of carboxyl-functional waterborne resins
- Superior hydrolytic stability compared to aziridine and isocyanate crosslinkers
- Water-dispersible grades eliminate need for co-solvent addition
- Long pot life in formulation with activation at ambient or slightly elevated temperatures