For windows, transparent covers and electronic films, an antistatic coating must meet both electrical and appearance requirements. An uncoated substrate control provides a starting point, so optical differences in the substrate are not mistakenly attributed to the coating.
Record transmittance and haze separately
ASTM D1003 covers light transmission and wide-angle scattering in planar transparent-plastic specimens.[1] A practical specification lists transmittance, haze and visible defects separately. Similar total transmittance does not establish the same scattering appearance. Color, local flow marks and particles need their own agreed observation conditions.
Controls and specimen revisions
Retain an uncoated control from the same substrate lot, and identify the number of coated faces, substrate thickness, film thickness and film-formation conditions in the specimen record. For curved or variable-thickness parts, a representative flat specimen may support material comparisons, followed by component-level visibility and appearance assessment. Label the two sets of results distinctly.
Optical and electrical data from the same sample set
A selection record can place initial optics, resistance under specified conditions and appearance after cleaning side by side, each with its test conditions and acceptance range. Enquiries for transparent antistatic materials can include the substrate grade, optical requirement, resistance target and existing coating process to define the sample plan.
Suggested project record
- Optical data
- Transmittance, haze, method and substrate thickness
- Appearance
- Lighting, background, inspected area and defect records
- Electrical data
- Specimen revision, measurement conditions and before/after-cleaning results