Boosting NIR Laser Marking Efficiency of a Transparent Epoxy Using a Layered Double Hydroxide

Area of Science:

• Materials Science
• Polymer Chemistry
• Laser Processing

Background:

• Transparent polymers like polypropylene, epoxy, and polyethylene exhibit poor absorption in the near-infrared (NIR) spectrum, hindering efficient laser marking.
• Current methods rely on inorganic additives, which often present challenges including toxicity, high loading requirements, and negative impacts on material properties.

Purpose of the Study:

• To develop a more efficient and safer coadditive for NIR laser marking on transparent polymers.
• To investigate the efficacy of a food-grade magnesium-aluminum carbonate layered double hydroxide (Mg2Al-CO3 LDH) as a boosting agent in epoxy systems.

Main Methods:

• Incorporation of Mg2Al-CO3 LDH as a coadditive with a commercial NIR laser marking agent (Iriotech 8815) in an epoxy matrix.
• Evaluation of marking quality (darkness, contrast, surface damage) at high laser head speeds (5000 mm/s).
• Assessment of material transparency and the readability of complex markings like QR codes.

Main Results:

• Mg2Al-CO3 LDH significantly improved marking darkness and contrast, even at high processing speeds.
• High substitution (95%) of the commercial additive with Mg2Al-CO3 LDH maintained epoxy transparency while yielding sharp, dark markings.
• Readable QR codes were achieved at high laser speeds, demonstrating the practical applicability of the new additive.

Conclusions:

• Mg2Al-CO3 LDH offers a promising, low-toxicity, and cost-effective solution for high-speed NIR laser marking on transparent polymers.
• This approach minimizes optical interference and adverse effects on material properties compared to traditional additives.
• The study highlights the potential of layered double hydroxides in advanced laser processing applications.