SikaBiresin CR72 Resin and CH72 Hardener System

Description

SikaBiresin CR72 epoxy is a 100 percent solids lamination and infusion system for fabricating and repairing high-performance composite structures. The low-viscosity resin is formulated for thorough fabric wetting and effective air release in wet layup and resin-infusion processes. Three CH72 hardeners provide fast, medium, and slow working-time choices, allowing the system to cover smaller repairs as well as larger laminates that require more placement or fill time.

SikaBiresin CR72 Epoxy Laminating and Infusion Applications

The system is used for marine structures, composite parts, molds, and repairs that depend on a high fiber-to-resin ratio. Its published UV-resistant formulation and low-viscosity mixtures support applications where clean wet-out, reduced trapped air, and manageable processing time are important. CR72 can be used for standard wet layup or resin infusion. Final suitability still depends on the reinforcement, tooling, laminate thickness, environmental conditions, and the specified cure schedule.

SikaBiresin CR72 Epoxy Cure Speeds

CH72-1 is the fast hardener, CH72-2 provides a medium window, and CH72-3 is the slow choice. Each standard option uses a published 100-to-18 mix ratio by weight. Sika’s product data lists mixed viscosity of roughly 350 to 650 cps depending on the selected hardener. Representative pot life ranges from about 30 minutes with the fast version to about 60 minutes with the slow version, giving fabricators a practical way to align working time with part scale and shop temperature.

Key System Data

• Chemistry: two-component epoxy lamination and infusion system
• Solids: 100 percent
• Processes: wet layup and resin infusion
• Standard hardeners: CH72-1 fast, CH72-2 medium, CH72-3 slow
• Mix ratio by weight: 100 resin to 18 hardener
• Mixed viscosity: approximately 350 to 650 cps
• Formulation: UV-resistant general-purpose composite system
• Typical work: composite fabrication and structural repair

Condition materials consistently, weigh the components accurately, and mix until the batch is uniform before introducing it to reinforcement. For infusion, verify the bag seal and flow plan before opening the resin inlet. For wet layup, remove trapped air while maintaining the specified resin content. For related options around SikaBiresin CR72 epoxy, browse Chemical Concepts epoxy products for related systems and application supplies. Visit Sika’s US composite materials resource for current manufacturer documents.

Need Help?

Need help selecting a hardener or comparing wet layup with infusion? Call (800) 220-1966 or email [email protected].