Organic Solvent-Resistant Grade Resin data sheet (PDF)Ask for a quote
An anti-corrosive grade with three listed services
SPR 301 OS is an anti-corrosive isophthalic polyester grade in Samrat Poly Resins’ SPR 301 family. The 2026 catalogue lists it for FRP linings for organic-solvent storage, for sewage pipes and for effluent-treatment equipment — three services where the laminate is in contact with a medium that attacks ordinary polyester.
It is non-thixotropic, with a typical viscosity of 200–400 cPs at 25 °C and gel time of 15–35 minutes at 25 °C, and is cured at the reference condition of MEKP 1.5% with cobalt octoate 0.4%, each added separately.
Why the solvent has to be named
“Organic solvent” covers chemicals as different as aliphatic hydrocarbons, aromatics such as toluene and xylene, alcohols, ketones, esters and chlorinated solvents. They swell and attack thermoset laminates by different mechanisms and at different rates, and temperature changes all of them.
So the useful question is never “is this resin solvent-resistant?” but “is it suitable for this solvent, at this concentration and temperature, in this kind of contact?” The catalogue publishes no solvent-by-solvent chart for SPR 301 OS, and a recommendation depends on those details.
Sewage and effluent service
Sewage and effluent streams are mostly water, but they carry dissolved chemicals, varying pH, biological activity and, in covered systems, gases that concentrate in the headspace. Municipal sewage and industrial effluent differ widely, and industrial streams differ from plant to plant.
For pipes and treatment equipment, the stream description matters as much as for a tank: source, pH range, temperature and any cleaning chemicals used on the system.
Working with a non-thixotropic resin
Being non-thixotropic, SPR 301 OS flows readily and wets reinforcement easily. On vertical lining faces that same flow means drainage has to be managed through stage thickness and technique. Its styrene content, 35–50% by weight typical, also calls for good ventilation, especially inside tanks and confined spaces.