Screen printing ink for plastic

Different plastics have different surface energies. For PP (Polypropylene) and PE (Polyethylene), you typically need solvent-based inks with a pretreatment (like flame or corona treatment) or specialized adhesion promoters. For ABS, PC (Polycarbonate), and PVC, UV-LED curable inks or evaporative drying solvent inks are preferred as they offer excellent chemical resistance and bonding without damaging the substrate.

To ensure global market access, verify that the ink is RoHS and REACH compliant, ensuring it is free from heavy metals and restricted phthalates. For sensitive applications like food packaging or toys, the ink must meet EN71-3 (Safety of Toys) or FDA-approved raw material standards. Always request a Material Safety Data Sheet (MSDS) and a Technical Data Sheet (TDS) from the supplier.

Prioritize testing for adhesion (Cross-hatch tape test) to ensure the ink doesn't peel. Additionally, evaluate alcohol resistance and scratch resistance, especially for consumer electronics or automotive parts. For outdoor applications, confirm the Lightfastness rating (Blue Wool Scale) to prevent premature fading under UV exposure.

UV-curable inks offer instant drying, which significantly increases throughput and reduces floor space needed for drying racks, though they require a higher initial investment in UV lamps. Solvent-based inks are generally cheaper per kilogram but require longer drying times and proper ventilation systems to manage Volatile Organic Compounds (VOCs).

Inks are often classified as Dangerous Goods (DG) due to flammability (solvent-based). You must ensure the supplier provides UN-certified packaging and a Certificate for Safe Transport of Chemical Goods. Failure to declare these correctly can lead to customs seizures or heavy fines at the port of entry.

Look for suppliers on Made-in-China.com that hold ISO 9001 (Quality Management) and ISO 14001 (Environmental Management) certifications. Check if they are an Audited Supplier by third-party agencies like SGS or Intertek, which confirms their production capacity and factory existence.

Request tiered pricing based on volume; typically, orders exceeding 500kg can see price reductions of 10-15%. Negotiate for free masterbatch samples for color matching (Pantone/RAL) before the main shipment to avoid costly color discrepancies in the final production run.

Utilize Secured Trading Services provided by Made-in-China.com to ensure payment is only released after the shipping documents are verified. For first-time large orders, consider a pre-shipment inspection to verify the batch numbers and expiration dates (shelf life) of the ink.