Product overview
Base resin for SMC/BMC compounds
POLYSTAR B-303 is designed for SMC/BMC compounds, with emphasis on gloss, thickening behaviour, fast cure and high reactivity.
Key TDS data
- Viscosity: 5–7 poise at 25°C
- Acid value: 15–19 mg KOH/g
- Volatile content: 37–41%
- Gel time: 12–14 minutes at 82°C
- Typical HDT: 120°C after the TDS post-cure schedule
- TDS gel data uses 1.0 phr BPO at 82°C
Use in compound formulation
- B-303 is an unpromoted polyester used as the base resin for SMC/BMC compounds cured at high mold temperature.
- Choose the initiator to suit mold temperature and press cycle; the TDS gel data use 1.0 phr BPO at 82°C, giving a gel time of 12–14 minutes.
- Good thickening response suits compound maturation before molding.
- Typical HDT of 120°C after the TDS post-cure, suited to hot-pressed parts requiring a glossy surface.
Formulation notes
Filler, thickener, fiber and low-profile additive levels strongly affect flow and surface quality. Any formulation change should be trialled on the production mold. See the SMC and BMC article in the Technical Center.
Storage
Store below 25°C away from sunlight and heat; keep containers closed after opening.
Request TDS / SDS
Current documents are provided by GKFRP upon request for the correct product grade and application.
Technical note
Values are taken from the supplied TDS and are not batch acceptance specifications. Review the current TDS/SDS and validate moulding or cure conditions before production.