PC sourcing: do not look only at transparency — MVR, impact and Vicat are more important
PC Selection · 2026year10month6day
PC is valued for transparency, impact resistance and heat resistance, but these properties depend on proper drying and the right grade. Looking only for “transparent PC” is often not enough to determine whether a grade suits a thin-wall part, structural component or optical part.
Include MVR, notched impact, HDT/Vicat, yellowing and drying conditions in the specification.
Typical parameters for Makrolon 2405
| Property | Typical Value | Test Conditions |
|---|---|---|
| MVR | 19 cm³/10 min | 300°C / 1.2 kg，ISO 1133 |
| Tensile Modulus | 2400 MPa | ISO 527 |
| Notched Izod | 60 kJ/m² | 23°C / 3 mm |
| Vicat | 145°C | 50 N，50°C/h |
| Glass Transition Temperature | 144°C | ISO 11357 |
These data indicate that MVR 19 is a low-viscosity general-purpose grade that is easy to injection mold while retaining relatively high room-temperature impact and heat-softening performance. Flame-retardant, reinforced, weatherable and optical PC grades can differ significantly; one general-purpose value cannot represent every application.
The drying step most often overlooked when sourcing PC
PC is sensitive to moisture. If pellets are not dried sufficiently, silver streaks, bubbles, molecular-chain degradation and reduced impact performance may occur after molding. Confirm the supplier's recommended drying temperature, time, packaging condition and post-opening storage requirements; on site, record dew point, melt temperature and residence time.
Select by product use
- Transparent protective covers and lighting parts: Focus on light transmittance, yellowing, weatherability and residual stress.
- Structural parts and electronic housings: Focus on impact, HDT, flame-retardant grade and dimensional stability.
- Complex thin-wall parts: Choose a higher MVR when strength requirements are met, and validate weld lines and shrinkage.
- Glass-fiber-reinforced PC: Rigidity and thermal performance increase, but anisotropy, warpage and appearance risks also increase.
Reference Documentation
parametersreference Covestro official Makrolon 2405 product page: Covestro Makrolon 2405. Actual data is subject to the latest TDS for the target color and grade.
Need PC grade and alternative-grade guidance?
Provide the wall thickness, transparency, flame-retardant and heat-resistance requirements; we will match a PC solution for validation.