Resin chemistry · SPR 301
Isophthalic Polyester Resins
Built on isophthalic acid rather than the phthalic anhydride of the orthophthalic grades, these resins are specified where a laminate faces water immersion, chemical service or sustained outdoor conditions. “ISO” here means isophthalic acid, not an ISO certification.
Grades in this family
General and anti-corrosive grades
- SPR 301ISO Polyester ResinGeneral isophthalic grade for water and chemical service.
- SPR 301 OTOil Storage Tank Grade ResinOil-storage-tank lining and chemical equipment.
- SPR 301 OSOrganic Solvent-Resistant Grade ResinOrganic-solvent storage, sewage and effluent service.
- SPR 301 RBRock Bolt Grade ResinLiquid base resin for rock-bolt anchoring compounds, not the finished capsule.
- SPR 301 FWFilament Winding Grade ResinNon-thixotropic grade for filament-wound pipes and tanks.
- SPR 301 CTIsophthalic Cooling Tower Grade ResinThixotropic grade for cooling-tower and wind-energy components.
- SPR 301 LVLow-Viscosity Grade ResinLow-viscosity grade for jute reinforcement.
SMC and DMC grades
- SPR 301 SMCIsophthalic SMC ResinSheet moulding compound resin.
- SPR 301 DMCIsophthalic DMC ResinDough moulding compound resin; a separate product from the SMC resin.
Fire-retardant grade
- SPR 301 FRISO Fire Retardant ResinHalogen-free, ATH-filled fire-retardant resin.
Gelcoat grade
- SPR 301 GCISO GelcoatIsophthalic gelcoat for brush and spray application.
Tooling grade (SPR 401 code range)
- SPR 401 TLTooling Grade ResinIsophthalic NPG-based mould resin. Its code sits in the SPR 401 range, but it is not terephthalic.
Selection guidance
- Water immersion, chemical or outdoor service: start from the general SPR 301 Isophthalic Polyester Resin.
- Tank linings: OT for oil-storage tanks and chemical equipment; OS for organic-solvent storage, sewage and effluent service.
- Process grades: FW for filament winding, CT for thixotropic cooling-tower and wind-energy lay-up, LV for jute impregnation.
- Rock-bolt anchoring: RB is the liquid base resin for the compound maker, not the finished capsule.
- Moulds: SPR 401 TL is the isophthalic NPG-based tooling grade.
This guidance identifies a starting grade only. Confirm the final choice against your own process and a trial.
Related application guides
Guides on the processes and applications this family serves.
Tell us which grade you need.
Describe the process, the finished part and its service conditions. Supply, pricing and packaging in Nepal are confirmed on enquiry.