UP SMC (Sheet molding compound)
Reinforced grade
GB GB/T 8237 · ISO 3672
Pick for high-volume compression-molded panels, electrical enclosures, water-tank panels and automotive body parts.
Values for the SMC 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 |
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 |
SMCThis page 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 SMC?
UP SMC is UP in the SMC grade — pick for high-volume compression-molded panels, electrical enclosures, water-tank panels and automotive body parts. UP SMC has a tensile strength of 75 MPa (10.9 ksi), stronger than 80% of polymer grades. Elongation at break is 1.2% and the elastic modulus is 12 GPa (1.74 Msi). UP SMC has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 96% of polymer grades. Its glass-transition temperature is 90°C (194 °F). Cast is the default condition FabDigit quotes; SMC is available on request or by drawing note.
Advantages
- Low, predictable mold shrinkage — 0.1%, better than 99% of polymer grades
- Stiff — 12 GPa (1.74 Msi), better than 98% of polymer grades
- Conducts heat well — 0.5 W/m·K (0.289 BTU/hr·ft·°F), better than 98% 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
- Low fracture toughness — 0.5 MPa·√m (0.455 ksi·√in), worse than 99% of polymer grades
- Limited ductility — 1.2%, worse than 98% of polymer grades
- Needs corrosion protection — 50/100, worse than 97% of polymer grades
- Heavy — 1.85 g/cm³ (0.0668 lb/in³), worse than 96% of polymer grades
- Limited formability — 5/100, worse than 95% of polymer grades
UP SMC properties
Typical room-temperature values for UP SMC; 18 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 SMC has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 96% of polymer grades. Its glass-transition temperature is 90°C (194 °F).
Mechanical15
UP SMC has a tensile strength of 75 MPa (10.9 ksi), stronger than 80% of polymer grades. Elongation at break is 1.2% and the elastic modulus is 12 GPa (1.74 Msi).
Thermal10
UP SMC is rated for continuous service to 150°C (302 °F). It conducts heat at 0.5 W/m·K (0.289 BTU/hr·ft·°F), better than 98% of polymer grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical7
UP SMC is an electrical insulator with a dielectric strength of 14 kV/mm (355.6 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 SMC 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 SMC's machinability is fair (35/100, worse than 84% 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 SMC
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 SMC — frequently asked
What is UP SMC used for?
UP SMC 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 SMC?
UP SMC has a typical tensile strength of 75 MPa (10.9 ksi) — stronger than 80% of polymer grades. Strength varies by condition: see the 11 listed tempers.
Is UP SMC easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% 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 SMC 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 SMC?
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 SMC 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 SMC?
UP SMC 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.