Desmocap branched aromatic ether/urethane resins are effective flexibilizers for epoxy coatings and sealants.
These non-solvent prepolymers are based on polyoxypropylene glycol (POPG) and toluene diisocyanate (TDI) and are blocked with alkylphenols. They react with amine crosslinkers and epoxy resins to form hybrid epoxy-urethane (polyurea-urethane-epoxy) polymers. The released alkylphenol remains in the coating and acts as a plasticizer.
The long, flexible polyoxypropylene units in Desmocap prepolymers decrease the crosslink density in the coating, which results in increased elasticity and improved impact resistance – even at lower temperatures.
Epoxies modified with Desmocap resins also have:
• Lower glass transition temperatures
• Improved adhesion and intercoat adhesion
Desmocap prepolymers are also used by themselves – individually or in combination – to prepare flexible coatings and sealants.