Quick facts
- Catalogue code
- SPR 401 DMC
- Chemistry
- Terephthalic unsaturated polyester
- Process
- DMC production, compression moulding, complex moulded parts
- Reference cure
- MEKP 1.5% + cobalt octoate 0.5%
What the grade is for
SPR 401 DMC is the terephthalic resin the catalogue lists for dough moulding compound production, compression-moulded composite components and complex moulded FRP parts. The catalogue calls it a separate product from the terephthalic SMC resin, with its own specification.
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 light-yellow liquid of 1,200–2,200 cPs at 25 °C — thicker than the terephthalic SMC resin — a gel time of 14–22 minutes at 25 °C (ambient QC), a specific gravity of 1.11–1.15 and 31–36% styrene by weight. It is supplied non-accelerated. Its reference cure uses slightly more cobalt than most of the range: MEKP 1.5% with cobalt octoate 0.5%, each added separately.
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.
DMC resins exist in three chemistries in the range: the orthophthalic DMC/SMC Resin (SPR 201), the isophthalic SPR 301 DMC, and this terephthalic grade. The DMC comparison guide sets them side by side.
Source, roles and the Nepal enquiry path
The values on this page are the typical specification printed for SPR 401 DMC 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 light-yellow liquid |
| Viscosity | 1,200–2,200 cPs at 25 °C |
| Gel time | 14–22 minutes at 25 °C (ambient QC) |
| Specific gravity | 1.11–1.15 |
| Styrene content | 31–36% by weight |
| Supply condition | Non-accelerated |
| Reference cure system | MEKP 1.5% + Cobalt Octoate 0.5% — 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 it thicker than the SMC resin?
The catalogue publishes 1,200–2,200 cPs for the DMC resin against 800–1,500 cPs for the SMC resin; they are separate products formulated for different compound forms.
What cobalt dosage does the catalogue give?
The reference cure is MEKP 1.5% with cobalt octoate 0.5%, added separately. Follow your confirmed process; never mix peroxide and cobalt directly.
Can it make complex parts?
The catalogue lists complex moulded FRP parts among its uses. The part design, compound and press cycle decide whether a particular part is achievable.