UP BMC (BMC/DMC)
Reinforced grade
GB GB/T 8237 · ISO 3672
For injection/compression-molded electrical parts — breakers, lamp holders, motor housings — needing arc resistance and dimensional stability.
Values for the BMC condition
Other UP grades and fills
UP is listed in 11 conditions; see the grade overview at UP.
Compare all 11 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Highly mineral-filled casting | 60–80% ATH/quartz/CaCO₃ filled casting resin for sinks, countertops, window sills and machine bases. | — | 25 | 0.4 | — |
Flexible / rubber-modified (impact-modified) resin | Blend or grade with higher elongation for buttons, encapsulation, patching and shock-loaded laminates. | 25 | 30 | 25 | 65 Shore D |
BMCThis page BMC/DMC | For injection/compression-molded electrical parts — breakers, lamp holders, motor housings — needing arc resistance and dimensional stability. | — | 40 | 0.6 | — |
Flame-retardant resin/compound | Specify for rail, building panels, ducting and electrical parts needing V-0 / EN 45545 / low smoke performance. | — | 45 | 1.2 | 88 Shore D |
Dicyclopentadiene modified, low-shrink / low styrene emission | Pick for low-shrink, low-VOC spray-up and thin bathware/marble parts where surface quality and styrene emission matter. | — | 50 | 1.5 | 86 Shore D |
CastDefault As cast | Baseline low-cost orthophthalic (191-type) resin cured with MEKP/Co — casting, putty, tooling and general hand-layup matrix. | — | 55 | 2 | 85 Shore D |
Bisphenol-A fumarate corrosion-resistant resin | For FRP tanks, ducts and scrubbers handling bleach, dilute alkali and hot chemicals where ortho/iso resins hydrolyse. | — | 60 | 2 | 88 Shore D |
Sheet molding compound | Pick for high-volume compression-molded panels, electrical enclosures, water-tank panels and automotive body parts. | — | 75 | 1.2 | — |
Vinyl ester resin | Highest chemical/blister resistance and toughness of the family — corrosion FRP linings, pipe, marine skin coats. | — | 80 | 5 | — |
GF30 | The standard fiberglass laminate for tanks, boats, panels and enclosures made on open molds. | — | 110 | 1.8 | — |
GF60 | Use for structural profiles, gratings, rebar and pipe where high axial stiffness and strength are needed. | — | 600 | 2 | — |
What is UP BMC?
UP BMC is UP in the BMC grade — for injection/compression-molded electrical parts — breakers, lamp holders, motor housings — needing arc resistance and dimensional stability. UP BMC has a tensile strength of 40 MPa (5.8 ksi), weaker than 56% of polymer grades. Elongation at break is 0.6% and the elastic modulus is 12 GPa (1.74 Msi). UP BMC has a density of 1.95 g/cm³ (0.0704 lb/in³), heavier than 97% of polymer grades. Its glass-transition temperature is 90°C (194 °F). Cast is the default condition FabDigit quotes; BMC is available on request or by drawing note.
Advantages
- Conducts heat well — 0.6 W/m·K (0.347 BTU/hr·ft·°F), better than 99% of polymer grades
- Stiff — 12 GPa (1.74 Msi), better than 98% of polymer grades
- Low, predictable mold shrinkage — 0.15%, better than 97% of polymer grades
- High service temperature — 150°C (302 °F), better than 79% of polymer grades
- Low embodied carbon — 3.4 kg CO₂/kg, better than 76% of polymer grades
Limitations
- Limited ductility — 0.6%, worse than 99% of polymer grades
- Low fracture toughness — 0.5 MPa·√m (0.455 ksi·√in), worse than 99% of polymer grades
- Heavy — 1.95 g/cm³ (0.0704 lb/in³), worse than 97% of polymer grades
- Needs corrosion protection — 50/100, worse than 97% of polymer grades
- Limited formability — 5/100, worse than 95% of polymer grades
UP BMC properties
Typical room-temperature values for UP BMC; 17 are specific to this condition. Other listed values are UP reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
UP BMC has a density of 1.95 g/cm³ (0.0704 lb/in³), heavier than 97% of polymer grades. Its glass-transition temperature is 90°C (194 °F).
Mechanical15
UP BMC has a tensile strength of 40 MPa (5.8 ksi), weaker than 56% of polymer grades. Elongation at break is 0.6% and the elastic modulus is 12 GPa (1.74 Msi).
Thermal10
UP BMC is rated for continuous service to 150°C (302 °F). It conducts heat at 0.6 W/m·K (0.347 BTU/hr·ft·°F), better than 99% of polymer grades. Thermal expansion is 22 µm/m·K (12.2 µin/in·°F).
Electrical7
UP BMC is an electrical insulator with a dielectric strength of 13 kV/mm (330.2 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 97% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of UP BMC takes about 70 MJ of energy and emits 3.4 kg of CO₂ — less than 93% of polymer grades. Typical recycled content is 0%.
Manufacturability6
UP BMC's machinability is good (55/100, worse than 64% of polymer grades); weldability not recommended (5/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with UP BMC
Is UP easy to machine?
Trim and drill cured laminate with carbide or diamond tooling, high speed / low feed, backing to prevent chipping; glass dust and styrene fumes require extraction and PPE.
Can UP be welded?
Not weldable — repair and join by secondary lamination (grind, wet out with CSM), or bond with polyester putty, MMA or epoxy adhesives.
Can UP be formed, bent or molded?
Cured by peroxide/cobalt at 20–30 °C (hand lay-up, spray-up, RTM, casting) or at 140–165 °C for SMC/BMC compression and injection; gel time 10–30 min, post-cure 60–80 °C for full Tg; control exotherm and 7–9% volumetric shrink.
What surface finishes work on UP?
Gel coat in the mold gives the finished colour/gloss; otherwise sand and spray 2K PU/acrylic, or wet-sand and buff cast surfaces — never anodize/plate directly without conductive primer.
UP chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| unsaturated polyester (maleic/fumaric + backbone polyester; iso-, NPG-, DCPD- or BPA-fumarate variants change acid/glycol | 55 – 70 | 65 |
| styrene (reactive diluent/crosslinker)LSE/DCPD grades run lower; MMA used in some castings | 28 – 45 | 35 |
| MEKP initiatoradded at use; BPO/TBPB for hot-cure SMC/BMC | 0.8 – 2 | 1.5 |
| cobalt octoate acceleratorwith DMA co-promoter for RT cure | 0.1 – 0.5 | 0.25 |
| hydroquinone/TBC inhibitorstorage stabilizer | 0.01 – 0.03 | 0.02 |
| glass fiber0% for cast resin; 25–30% SMC, 15–25% BMC, 55–70% pultrusion | 0 – 70 | 30 |
| mineral filler (CaCO3 / ATH / quartz)40–50% in SMC/BMC, 60–80% in cultured marble; ATH also gives FR/low smoke | 0 – 80 | 0 |
UP BMC — frequently asked
What is UP BMC used for?
UP BMC is typically used for fiberglass boat hulls, SMC/BMC molded parts, composite panels and bathroom fixtures (tub/shower). In short: cheapest FRP matrix; standard SMC/BMC resin; 85 °C service limit.
What is the tensile strength of UP BMC?
UP BMC has a typical tensile strength of 40 MPa (5.8 ksi) — weaker than 56% of polymer grades. Strength varies by condition: see the 11 listed tempers.
Is UP BMC easy to machine?
Reasonably — machinability is rated good (55/100, worse than 64% of polymer grades). Trim and drill cured laminate with carbide or diamond tooling, high speed / low feed, backing to prevent chipping; glass dust and styrene fumes require extraction and PPE.
Can UP BMC be welded?
Not readily — weldability is rated not recommended (5/100). Not weldable — repair and join by secondary lamination (grind, wet out with CSM), or bond with polyester putty, MMA or epoxy adhesives.
What surface finishes work on UP BMC?
Gel coat in the mold gives the finished colour/gloss; otherwise sand and spray 2K PU/acrylic, or wet-sand and buff cast surfaces — never anodize/plate directly without conductive primer.
Can UP BMC be formed, bent or molded?
Cured by peroxide/cobalt at 20–30 °C (hand lay-up, spray-up, RTM, casting) or at 140–165 °C for SMC/BMC compression and injection; gel time 10–30 min, post-cure 60–80 °C for full Tg; control exotherm and 7–9% volumetric shrink.
What is the maximum service temperature of UP BMC?
UP BMC is rated for continuous use to about 150°C (302 °F), and briefly to 130°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between UP Cast and UP Tough?
Cast is the default condition — baseline low-cost orthophthalic (191-type) resin cured with MEKP/Co — casting, putty, tooling and general hand-layup matrix. Tough: blend or grade with higher elongation for buttons, encapsulation, patching and shock-loaded laminates.
Sources
- ASTM D1201 / D2583 (Barcol hardness) and ISO 3672 Unsaturated-polyester resins — designation & basis for specifications — ASTM / ISO (2000)
- Engineered Materials Handbook Vol.2: Engineering Plastics / Vol.1 Composites — ASM International (1988)
- Unsaturated polyester & vinyl ester resin datasheets (AOC, Reichhold/Polynt, Ashland/INEOS Derakane, / / ) — various resin producers (2024)
- CAMPUS / UL Prospector entries for UP-GF, SMC and BMC moulding compounds — CAMPUS / UL (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.