Resin chemistry · SPR 401
Terephthalic Polyester Resins
Terephthalic grades for moulding compounds, a fire-retardant gelcoat and continuous pultrusion. One grade in the SPR 401 code range, the SPR 401 TL tooling resin, is isophthalic rather than terephthalic and is listed separately below.
Grades in this family
SMC and DMC grades
- SPR 401 SMCTerephthalic SMC ResinSheet moulding compound resin.
- SPR 401 DMCTerephthalic DMC ResinDough moulding compound resin with its own specification.
Fire-retardant gelcoat grade
- SPR 401 FRGCTerephthalic Fire-Retardant Gelcoat ResinFire-retardant surface gelcoat for rail and transport parts.
Pultrusion grade
- SPR 401 PTPultrusion Grade ResinContinuous pultrusion on a heat-activated peroxide system.
Code-range exception
SPR 401 TL
SPR 401 TL Tooling Grade Resin keeps an SPR 401 code but is an isophthalic NPG-based resin, not a terephthalic one. It is classified under Isophthalic Polyester Resins.
Selection guidance
- SMC and DMC: choose the family by the chemistry the compound requires — orthophthalic, isophthalic or terephthalic.
- Fire-retardant gelcoat: pair SPR 401 FRGC with the fire-retardant laminating resin of the same project.
- Pultrusion: SPR 401 PT runs on a heat-activated peroxide system, not the ambient MEKP and cobalt system.
This guidance identifies a starting grade only. Confirm the final choice against your own process and a trial.
Related application guides
Guides on the processes and applications this family serves.
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