Solder Mask Ink
CAS Number: 25036-25-3
Solder mask ink is a photoimageable or thermally cured polymer coating applied to PCB surfaces to protect copper traces from oxidation and prevent solder bridging during assembly. It defines the solderable pad openings with high precision and provides long-term electrical insulation and chemical resistance. Available in liquid photoimageable (LPI) and dry film formats with green, red, blue, and black color options.
Technical Specifications
| hardness | 6H pencil hardness |
| viscosity | 80–200 dPa·s |
| appearance | Green, red, blue, or black liquid |
| resolution | ≤75 µm line/space (LPI grade) |
| insulationResistance | >10¹² Ω after humidity |
| solderFloatResistance | 288°C / 10s (IPC-SM-840) |
Applications
- PCB surface copper trace protection
- Solder pad opening definition
- PCB electrical insulation layer
- High-density interconnect (HDI) PCB
- Flex and rigid-flex PCB masking
Key Features
- High-resolution imaging for fine-pitch PCB designs
- Excellent solder and flux chemical resistance
- Tack-free surface for clean handling
- UL 94 V-0 flammability rating