Quick facts
- Catalogue code
- SPR 301 OT
- Chemistry
- Isophthalic unsaturated polyester
- Role
- FRP lining of oil storage tanks; chemical-equipment manufacturing
- Listed properties
- Good electrical and heat-resistance properties
What the grade is for
SPR 301 OT is the oil-storage-tank grade of the isophthalic family. The catalogue describes it as an isophthalic grade with good electrical and heat-resistance properties, for the FRP lining of oil storage tanks, and also lists chemical-equipment manufacturing. It exists because a tank lining lives in permanent contact with its contents, which is exactly the service the isophthalic chemistry is chosen for.
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, pale-yellow to light-amber liquid of 300–600 cPs at 25 °C, a gel time of 15–35 minutes at 25 °C, a specific gravity of 1.04–1.14 and 33–45% styrene by weight. It is supplied non-accelerated, with a reference cure of MEKP 1.5% and cobalt octoate 0.4%, each added separately. The ranges are typical values for the grade, not a promise for a particular batch.
Questions to settle before specifying a lining
What exactly will the tank hold, at what temperature, and will anything else be stored in it later? Is the lining a new build or a refurbishment? What does the tank owner’s specification require of the lining’s thickness and inspection? Those answers decide whether an isophthalic lining is appropriate, or whether the service calls for SPR 301 OS or a vinyl ester lining.
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.
Within the range, SPR 301 OS is listed for organic-solvent storage, sewage pipes and effluent equipment, and Vinyl Ester Resin (SPR 501) is the route for more aggressive chemical service. The comparison guide on these three grades sets out how the decision is usually made.
Source, roles and the Nepal enquiry path
The values on this page are the typical specification printed for SPR 301 OT 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, pale-yellow to light-amber liquid |
| Viscosity | 300–600 cPs at 25 °C |
| Gel time | 15–35 minutes at 25 °C |
| Specific gravity | 1.04–1.14 |
| Styrene content | 33–45% by weight |
| Supply condition | Non-accelerated |
| 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
Is SPR 301 OT compatible with every oil?
The grade is listed for oil-storage-tank lining. That is not a compatibility guarantee for every product; the stored product, concentration and temperature decide suitability.
What does “good electrical properties” mean for a tank?
The catalogue lists good electrical and heat-resistance properties for this grade without publishing figures. If a project depends on a specific electrical value, ask for it to be confirmed before ordering.
When is vinyl ester the better lining?
When the chemical, its concentration or the temperature is beyond what an isophthalic lining is specified for. The decision is made on the actual service, not on the resin name.