DAP MDG
Reinforced grade
ASTM D5948 Type SDG
MDG = mineral (clay/silica) filled DAP
Choose the clay/silica mineral-filled compound for economical, dimensionally stable switches and terminal blocks with the best arc and tracking resistance; tensile strength drops to 40 MPa.
Values for the MDG condition
Other DAP grades and fills
DAP is listed in 6 conditions; see the grade overview at DAP.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
MDGThis page Mineral (clay/silica) filled DAP | Choose the clay/silica mineral-filled compound for economical, dimensionally stable switches and terminal blocks with the best arc and tracking resistance; tensile strength drops to 40 MPa. | — | 40 | — | — |
Synthetic (acrylic/polyester) fiber filled DAP | Pick acrylic or polyester fiber filling for the lowest density (1.4 g/cm³) plus best toughness and arc resistance in weight-critical aerospace connectors and thin-wall radomes; 150 °C limit. | — | 45 | — | — |
Flame-retardant / UL 94 V-0 listed DAP | Specify when a UL Yellow Card V-0 listing with guaranteed CTI and glow-wire ratings is required for electrical parts; tensile strength settles near 50 MPa in exchange for the flame-retardant package. | — | 50 | 0.5 | 112 HRM |
SDG-FDefault Short glass-fiber filled DAP molding compound | Default general-purpose grade: short glass fiber gives 55 MPa tensile and 180 °C service for military and aerospace connectors and relay parts balancing strength, heat and insulation. | — | 55 | — | — |
Glass-filled diallyl isophthalate | Choose the isophthalate-based glass-filled compound for continuous service above 200 °C in high-temperature connectors and motor insulation, where the standard orthophthalate types fall short. | — | 60 | — | — |
Long glass-fiber (high-impact) DAP | Use long glass fiber for load-bearing or impact-loaded thick-wall insulators needing 70 MPa and 185 °C service, accepting poor flow that limits it to compression or transfer molding. | — | 70 | 0.9 | 108 HRM |
What is DAP MDG?
DAP MDG is DAP in the MDG grade — choose the clay/silica mineral-filled compound for economical, dimensionally stable switches and terminal blocks with the best arc and tracking resistance; tensile strength drops to 40 MPa. DAP MDG 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 10.5 GPa (1.52 Msi). DAP MDG has a density of 1.9 g/cm³ (0.0686 lb/in³), heavier than 97% of polymer grades. Its glass-transition temperature is 160°C (320 °F). SDG-F is the default condition FabDigit quotes; MDG is available on request or by drawing note.
Advantages
- Conducts heat well — 0.5 W/m·K (0.289 BTU/hr·ft·°F), better than 98% of polymer grades
- Stiff — 10.5 GPa (1.52 Msi), better than 95% of polymer grades
- High service temperature — 165°C (329 °F), better than 81% of polymer grades
- Good UV / weathering resistance — 55/100, better than 77% of polymer grades
Limitations
- Limited formability — 0/100, worse than 100% of polymer grades
- Limited ductility — 0.6%, worse than 99% of polymer grades
- Difficult to weld — 0/100, worse than 98% of polymer grades
- Heavy — 1.9 g/cm³ (0.0686 lb/in³), worse than 97% of polymer grades
- Difficult to machine — 45/100, worse than 78% of polymer grades
DAP MDG properties
Typical room-temperature values for DAP MDG; 11 are specific to this condition. Other listed values are DAP reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
DAP MDG has a density of 1.9 g/cm³ (0.0686 lb/in³), heavier than 97% of polymer grades. Its glass-transition temperature is 160°C (320 °F).
Mechanical9
DAP MDG 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 10.5 GPa (1.52 Msi).
Thermal10
DAP MDG is rated for continuous service to 165°C (329 °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 35 µm/m·K (19.4 µin/in·°F).
Electrical7
DAP MDG is an electrical insulator with a dielectric strength of 16 kV/mm (406.4 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 52% of polymer grades. UV resistance is good.
Sustainability3
Producing a kilogram of DAP MDG takes about 105 MJ of energy and emits 5.5 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 0%.
Manufacturability6
DAP MDG's machinability is fair (45/100, worse than 78% of polymer grades); weldability not recommended (0/100); formability not recommended (0/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with DAP MDG
Is DAP easy to machine?
Turning, milling, drilling and tapping are all possible, but glass and mineral fillers are highly abrasive — use carbide or PCD tooling with low feed and dust extraction. The material is brittle, so back up drill exits to prevent breakout.
Can DAP be welded?
Cross-linked thermoset; it cannot be melt-welded. Join with epoxy or cyanoacrylate adhesive or mechanical fasteners — moulded-in metal inserts are the most common method.
Can DAP be formed, bent or molded?
Processed by compression, transfer or thermoset screw injection moulding: preheat the compound to 90–105 °C, run mould temperature 145–180 °C and cure about 30–60 s/mm. There is no post-shrinkage, so dimensions stay stable; pay attention to venting and flash control.
What surface finishes work on DAP?
Parts leave the tool with a matte or gloss surface and usually need no secondary work; deflash, bead blast, laser mark or print as required. Surface energy is low, so plasma treatment or a primer is needed before painting or plating.
DAP 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 |
|---|---|---|
| diallyl phthalate prepolymer + monomer (diallyl phthalate prepolymer and monomer matrix | 25 – 45 | 35 |
| glass fiberchopped glass fiber (SDG-F) | 15 – 40 | 25 |
| mineral filler (clay / silica / CaCO3)primary filler in MDG grades | 20 – 45 | 35 |
| organic peroxide initiator (e.g. dicumyl | 0.5 – 2 | 1 |
| mold release / lubricant (metallic stear | 0.3 – 1.5 | 0.8 |
| pigment / stabilizer | 0.2 – 2 | 0.7 |
DAP MDG — frequently asked
What is DAP MDG used for?
DAP MDG is typically used for electrical connectors, terminal blocks, aerospace connector housings and precision insulators. In short: dimensionally stable thermoset; low moisture pickup; connector-grade insulation.
What is the tensile strength of DAP MDG?
DAP MDG has a typical tensile strength of 40 MPa (5.8 ksi) — weaker than 56% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is DAP MDG easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 78% of polymer grades). Turning, milling, drilling and tapping are all possible, but glass and mineral fillers are highly abrasive — use carbide or PCD tooling with low feed and dust extraction. The material is brittle, so back up drill exits to prevent breakout.
Can DAP MDG be welded?
Not readily — weldability is rated not recommended (0/100). Cross-linked thermoset; it cannot be melt-welded. Join with epoxy or cyanoacrylate adhesive or mechanical fasteners — moulded-in metal inserts are the most common method.
What surface finishes work on DAP MDG?
Parts leave the tool with a matte or gloss surface and usually need no secondary work; deflash, bead blast, laser mark or print as required. Surface energy is low, so plasma treatment or a primer is needed before painting or plating.
Can DAP MDG be formed, bent or molded?
Processed by compression, transfer or thermoset screw injection moulding: preheat the compound to 90–105 °C, run mould temperature 145–180 °C and cure about 30–60 s/mm. There is no post-shrinkage, so dimensions stay stable; pay attention to venting and flash control.
What is the maximum service temperature of DAP MDG?
DAP MDG is rated for continuous use to about 165°C (329 °F), and briefly to 230°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D5948 Standard Specification for Molding Compounds, Thermosetting — ASTM International (2019)
- MIL-M-14H Molding Plastics and Molded Plastic Parts, Thermosetting — US DoD (1989)
- Engineered Materials Handbook Vol.2: Engineering Plastics — ASM International (1988)
- DAP/DAIP molding compound datasheets (allyl compounders) — Cosmic Plastics / Daiso / Polymics (2023)
- UL Yellow Card / IEC 60112, 60695 electrical ratings for allyl compounds — UL Solutions (2023)
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.