Manufacturing Process of White Polycarbonate (PC) Core Sheet for ID Cards

1. Raw Material Preparation
Polycarbonate (PC) Resin: High-purity optical grade PC granules are used for excellent transparency, dimensional stability, and laser engraving capability.

White Masterbatch: A dispersion of titanium dioxide (TiO₂) in PC resin, providing high whiteness and opacity.

Additives (if needed):

UV stabilizers

Heat stabilizers

Flow modifiers

All materials must be dry and free from moisture, as PC is highly sensitive to water absorption. Pre-drying is done at 100–120°C for 4–6 hours in a dehumidifying dryer.

2. Compounding / Color Masterbatch Preparation (if not pre-made)
If producing the white PC masterbatch in-house:

PC resin is compounded with TiO₂ using a twin-screw extruder.

The output is cooled and pelletized into a white PC masterbatch.

The masterbatch is then mixed with base PC at the desired ratio during sheet extrusion.

3. Sheet Extrusion Process
Feeding: Dry PC resin and white masterbatch are fed into the extruder.

Melting: The material is melted in a temperature-controlled extruder (typically 250–290°C).

Sheet Formation: The molten material passes through a flat T-die to form a sheet.

Calendering:

The extruded sheet goes through a polishing stack (mirror-finish rollers) to control surface finish and thickness.

Cooling: The sheet is gradually cooled to prevent stress and warping.

Haul-off and Cutting: Sheets are pulled by a roller system and cut to size (e.g., 310 × 480 mm or customized dimensions).

4. Surface Characteristics
Thickness: Typically 0.2 mm to 0.6 mm depending on card layer design.

Surface Finish:

Matte, gloss, or fine-textured as per lamination requirement.

Smooth enough for bonding, but not slippery to prevent delamination.

White Opacity: Controlled via TiO₂ content to ensure laser readability in final card structure.

5. Application in ID Card Lamination
White PC core sheets are usually the middle layer in a multi-layer PC ID card construction. 

Lamination Conditions:

Temperature: 170–200°C

Pressure: 8–15 MPa

Time: 15–30 minutes (depends on layer count and equipment)

Post-lamination:

Cooling under pressure to avoid warping.

Laser engraving or personalization.

Card punching and finishing.

Key Advantages of PC Core Sheets in ID Cards
High durability (10+ year lifespan)

Tamper resistance

Laser engravability

High bonding strength (no adhesives required)

Resistant to moisture, temperature, and chemicals