Quick facts
- Catalogue code
- SPR 301 FW
- Chemistry
- Non-thixotropic isophthalic unsaturated polyester
- Role
- Filament-wound FRP pipes and tanks
- Listed properties
- High binding properties and high strength
Why winding needs its own grade
In filament winding, continuous fibre passes through a resin bath and is wound under tension onto a rotating mandrel. The resin must flow freely into the fibre in the bath and stay workable for as long as the winding takes. SPR 301 FW is the isophthalic grade the catalogue lists for that process, described as having high binding properties and high strength, for filament-wound FRP pipes and tanks.
Reading the published values
The catalogue lists a clear, light-yellow to amber liquid of 200–400 cPs at 25 °C, a gel time of 20–60+ minutes at 25 °C, a specific gravity of 1.04–1.14 and 35–45% styrene by weight. It is supplied non-accelerated and non-thixotropic, with a reference cure of MEKP 1.5% and cobalt octoate approximately 0.4%, each added separately. The long gel-time range reflects a process in which the bath has to stay usable.
Limitations and alternatives
The resin does not decide a pipe’s pressure rating or a tank’s service life; the winding pattern, fibre content, wall build-up and liner do. For wound parts in more aggressive chemical service, compare with Vinyl Ester Resin. For hand lay-up in water or chemical service, the general SPR 301 grade is the catalogue’s starting point, and for continuous profiles the pultrusion grade SPR 401 PT is the relevant process resin.
Source, roles and the Nepal enquiry path
The values on this page are the typical specification printed for SPR 301 FW 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-yellow to amber liquid |
| Viscosity | 200–400 cPs at 25 °C |
| Gel time | 20–60+ minutes at 25 °C |
| Specific gravity | 1.04–1.14 |
| Styrene content | 35–45% by weight |
| Supply condition | Non-accelerated · non-thixotropic |
| Reference cure system | MEKP 1.5% + Cobalt Octoate approximately 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
Why is the grade non-thixotropic?
Filament winding needs a resin that flows freely through the bath and into the fibre, so the grade is supplied non-thixotropic.
Does it give my pipe a pressure rating?
No. A pressure rating belongs to the pipe design and its testing, not to the resin alone.
Is vinyl ester better for wound pipes?
Neither is universally better. Vinyl ester is usually considered where the chemical service is more aggressive; the actual service decides.