Quick facts
- Catalogue code
- SPR 401 SMC
- Chemistry
- Terephthalic unsaturated polyester
- Process
- SMC production, compression moulding, hot-mould processing
- Specification
- Its own; not shared with SPR 401 DMC
What the grade is for
SPR 401 SMC is the terephthalic resin the catalogue lists for sheet moulding compound production, compression-moulded composite components and hot-mould processing. It is described as having high heat-resistant capacity, good resistance to corrosive chemicals and strong mechanical and impact properties.
Chemistry
A terephthalic polyester is built on terephthalic acid, the para isomer of the phthalic acids. In the catalogue, the terephthalic family carries the grades described with high heat resistance and strong mechanical properties: the SMC and DMC resins, the fire-retardant gelcoat and the pultrusion grade.
Reading the published values
The catalogue lists a clear to slightly hazy, pale-yellow to light-amber liquid of 800–1,500 cPs at 25 °C, a gel time of 12–18 minutes at 25 °C (an ambient QC figure), a specific gravity of 1.11–1.15 and 32–38% styrene by weight. It is supplied non-accelerated with a reference cure of MEKP 1.5% and cobalt octoate 0.4%, each added separately. Heat resistance is stated in words; no heat-deflection figure is published for the grade.
Limitations and alternatives
A moulded part’s properties come from the whole compound — resin, filler, reinforcement, thickeners — and from the press cycle, not from the resin alone. Resin data describes the resin.
The catalogue’s guidance for SMC and DMC is to choose the family by the chemistry the compound requires: orthophthalic (DMC/SMC Resin, SPR 201), isophthalic (SPR 301 SMC) or terephthalic (this grade). The SMC comparison guide sets the three side by side.
Source, roles and the Nepal enquiry path
The values on this page are the typical specification printed for SPR 401 SMC 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 to slightly hazy, pale-yellow to light-amber liquid |
| Viscosity | 800–1,500 cPs at 25 °C |
| Gel time | 12–18 minutes at 25 °C (ambient QC) |
| Specific gravity | 1.11–1.15 |
| Styrene content | 32–38% 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 a terephthalic SMC resin always better than an orthophthalic one?
No. The catalogue describes its heat and chemical resistance; whether a part needs that is decided by the part’s service, and the compound’s chemistry is chosen to match.
Does it share a specification with SPR 401 DMC?
No. Unlike the isophthalic pair, the terephthalic DMC resin has its own specification.
Is a heat-deflection temperature published?
Not for this grade. If a project needs a figure, ask for it to be confirmed before ordering.