Quick facts
- Catalogue code
- SPR 301 CT
- Chemistry
- Thixotropic isophthalic unsaturated polyester
- Role
- Cooling-tower and wind-energy composite components
- Orthophthalic counterpart
- SPR 201 CTG
The isophthalic route for tower work
SPR 301 CT is the thixotropic grade of the isophthalic family. The catalogue describes heat, chemical and corrosion resistance with high strength, and lists cooling-tower and wind-energy composite components. Its selection guide names it as the isophthalic route for the sag-resistant lay-up that the orthophthalic SPR 201 CTG also serves.
Reading the viscosity pair and thixotropic index
Unlike the orthophthalic grade, the catalogue publishes this grade’s thixotropy directly: 400–650 cPs at 60 rpm, 1,500–2,000 cPs at 6–12 rpm, and a thixotropic index of 2.0–3.5. The higher low-speed reading is what holds the resin on a vertical surface. It also lists a cloudy to amber liquid, a gel time of 15–35 minutes at 25 °C, a specific gravity of 1.10–1.15 and 37–45% styrene by weight, supplied non-accelerated and thixotropic with a reference cure of MEKP 1.5% and cobalt octoate 0.4%, each added separately.
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.
Where the tower’s service is mild, the orthophthalic SPR 201 CTG may be sufficient; the comparison guide on the two cooling-tower grades sets out the difference. Resin data does not guarantee the life of a finished component.
Source, roles and the Nepal enquiry path
The values on this page are the typical specification printed for SPR 301 CT 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 | Cloudy to amber liquid |
| Viscosity — 60 rpm | 400–650 cPs |
| Viscosity — 6–12 rpm | 1,500–2,000 cPs |
| Thixotropic index | 2.0–3.5 |
| Gel time | 15–35 minutes at 25 °C |
| Specific gravity | 1.10–1.15 |
| Styrene content | 37–45% by weight |
| Supply condition | Non-accelerated · 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
What is a thixotropic index?
It compares the viscosity at low and high speed. A higher index means the resin thickens more at rest; the catalogue lists 2.0–3.5 for this grade.
CT or CTG — which do I need?
SPR 201 CTG is orthophthalic; SPR 301 CT is isophthalic, listed with heat, chemical and corrosion resistance. The tower’s service conditions decide.
Is it suitable for wind-turbine blades?
The catalogue lists wind-energy composite components. Suitability for a specific structural part is decided by that part’s design and testing.