Material Selection
Choosing the right resin for your CIPP project
The resin system in a CIPP liner determines its chemical resistance, mechanical performance, curing method compatibility, and project economics. This guide walks through the three main resin chemistries — unsaturated polyester, vinyl ester, and UV-curable — and the project conditions that favor each.
Unsaturated Polyester Resin
Unsaturated polyester (UP) resin is synthesized from dibasic acids and diols. It is the cost-leader among CIPP resins and is widely deployed for municipal drainage rehabilitation.
- Best for: Large-diameter drainage; near-neutral pH media; cost-sensitive projects
- Avoid for: Strongly acidic or alkaline media; high-temperature service
- Curing: Steam, hot water, or UV initiator
- Cost: Lowest among CIPP resins
Vinyl Ester Resin (Epoxy Ester)
Vinyl ester resin combines epoxy backbone chemistry with vinyl reactive groups, providing exceptional hydrolysis resistance and stability against acids and alkalis.
- Best for: Industrial wastewater; chemical plant effluent; small-diameter inversion CIPP
- Avoid for: Cost-driven large-diameter rehabilitation where polyester is sufficient
- Curing: Steam, hot water, ambient cure with catalyst
- Cost: Higher than polyester (typically 1.5-2x)
UV-Curable Resin
UV-curable resin contains a photo-initiator that polymerizes when exposed to ultraviolet light, eliminating the need for steam or hot water curing.
- Best for: UV-CIPP systems; year-round construction; potable water rehab
- Avoid for: Steam-cure-only inversion projects without UV equipment
- Curing: UV light train (photo-initiator)
- Cost: Comparable to vinyl ester
Decision matrix
Use the following decision logic:
- Is the conveyed media chemically aggressive (strong acid/base)? → Vinyl ester
- Is the project potable water rehab? → UV-curable (sanitary cert)
- Is year-round construction critical? → UV-curable
- Is the project large-diameter drainage with neutral pH? → Unsaturated polyester
- Is the project a building drain stack with mild media? → Unsaturated polyester
Sanitary certification
For potable water rehabilitation, the resin and curing agent must hold sanitary certification. Huatao's UV-curable resin systems carry sanitary certification compliant with German DIN drinking water standards.
For project-specific resin selection, share your conveyed media composition (pH, temperature, contaminants) with our engineers.
