Quick facts
- Catalogue code
- SPR 301 OS
- Chemistry
- Isophthalic unsaturated polyester (anti-corrosive grade)
- Role
- Organic-solvent storage linings, sewage pipes, effluent equipment
- Supply
- Non-accelerated · non-thixotropic
What the grade is for
SPR 301 OS is one of the anti-corrosive grades of the isophthalic family. The catalogue describes corrosion resistance against organic solvents with good chemical and heat resistance, and lists FRP linings for organic-solvent storage, sewage pipes and effluent-treatment equipment.
Chemistry
An isophthalic polyester is built on isophthalic acid rather than the phthalic anhydride of general-purpose grades. The industry specifies it where a laminate faces water immersion, chemical service or sustained outdoor conditions, because the isophthalic backbone resists the slow attack of water on its ester links better. “ISO” here means isophthalic acid, not an ISO certification.
Reading the published values
The catalogue lists a clear, light-straw to reddish-amber liquid of 200–400 cPs at 25 °C, a gel time of 15–35 minutes at 25 °C, a specific gravity of 1.03–1.15 and 35–50% styrene by weight. It is supplied non-accelerated and non-thixotropic, with a reference cure of MEKP 1.5% and cobalt octoate 0.4%, each added separately.
Why “solvent-resistant” needs a name attached
“Organic solvents” covers a very wide range of chemicals, and they do not all behave the same way against a polyester laminate. A grade intended for organic-solvent service is a starting point, not a verdict. Name the solvent, its concentration and the operating temperature, and state whether the lining sees splash, intermittent or permanent contact.
Limitations and alternatives
Chemical-resistance wording describes the service the grade is intended for. It is not a compatibility chart: the specific chemical, its concentration and the temperature decide whether a laminate will last, and those have to be stated when you enquire.
For oil-storage-tank lining the family carries SPR 301 OT; for more aggressive chemical service, Vinyl Ester Resin (SPR 501). For general effluent and process tanks, the existing guide on FRP effluent and process tanks explains where an isophthalic laminate usually sits.
Source, roles and the Nepal enquiry path
The values on this page are the typical specification printed for SPR 301 OS in the supplier’s 2026 product catalogue. Samrat Poly Resins has since published a Technical Data Sheet for this grade, linked from the product page; its figures and the catalogue’s agree, and the catalogue is the source named beside every figure here.
Samrat Poly Resins, India manufactures the grade and issues its technical information. Samrat FRP Traders is the Nepal supplier and importer and handles enquiries; price, packaging, lead time and stock in Nepal are confirmed on enquiry.
Key properties
| Property | Typical value |
|---|---|
| Appearance | Clear, light-straw to reddish-amber liquid |
| Viscosity | 200–400 cPs at 25 °C |
| Gel time | 15–35 minutes at 25 °C |
| Specific gravity | 1.03–1.15 |
| Styrene content | 35–50% by weight |
| Supply condition | Non-accelerated · non-thixotropic |
| Reference cure system | MEKP 1.5% + Cobalt Octoate 0.4% — added separately during use |
Source: Samrat Poly Resins, India — product catalogue, 2026 edition (typical specification). Typical values describe the grade; they are not batch guarantees or acceptance limits.
Frequently asked questions
Does SPR 301 OS resist all organic solvents?
No resin does. The grade is intended for organic-solvent service; the specific solvent, concentration and temperature decide suitability.
Can it be used for sewage pipes?
The catalogue lists sewage pipes and effluent-treatment equipment among its uses. The pipe design and the effluent composition still have to be confirmed.
What does non-thixotropic mean for lining work?
The resin flows freely and does not thicken at rest. That suits wet-out of reinforcement; on vertical walls, build-up and gel time need to be managed in the process.