Introduction:

Bulk molding compound (BMC) is a mineral filled, fiberglass reinforced polyester (vinyl ester and phenolic) based molding compound. BMC is a thermosetting material that undergoes an irreversible corss-linking reaction when exposed to the heat and pressure of the thermset molding process (i.e. ambient delivery of material to a heated molding surface). A somewhat tacky, dough-like mass in its unmolded state, BMC is converted to an infusible, solid state using injection, compression and transfer methods.

Bulk moulding compound (BMC) or bulk molding composite is a ready to mould fibre-reinforced thermoset polyester material primarily used in injection and compression moulding. The material is provided in bulk or logs.

BMC is manufactured by mixing stands (>1”) of chopped glass fibers in a mixer with polyester resin. The glass fibers in BMC result in better strength properties than standard plastic products.

BMC provides a competitive alternative to die cast and drawn metals, sheet molding products and engineering thermoplastics.

Notable BMC properties:

1. Resistance to creep;
2. Discoloration when exposed to heat and load;
3. Notched impact performance;
4. High modulus;
5. Surface durability (resistant to reagent/stain, chemical, scratch and ultra violet attack).

BMC can be formulated to meet specific a performance profile.

This unique customization allows for the elimination of costly additives and reinforcements where possible.

This “cafeteria approach” to material development sets BMC apart when evaluating price versus performance properties.

Applications:

BMC is mainly used in metal and costly engineering thermoplastic (ETP) replacement.

Typical applications include demanding electrical applications, corrosion resistant needs, appliance, automotive, and transit.