Label Materials for Flexographic Printing Machines

Flexographic printing machines are widely used in the field of label printing, especially suitable for production scenarios that require high-volume, high-speed, and high environmental protection standards. They are compatible with a wide range of label materials, which are mainly selected based on the characteristics of the substrate, the requirements for printing effects, and the subsequent processing methods.

1. Common Label Materials

1. ‌Self-adhesive materials (pressure-sensitive label paper)‌
   This is one of the most widely used materials in flexographic printing, suitable for labels on food, daily chemicals, pharmaceuticals, etc.

• Common substrates: coated paper, mirror-coated paper, synthetic paper (e.g., BOPP, PET), brittle paper

• Features: suitable for automatic labeling, roll-fed printing, and highly compatible with water-based or UV inks

• Applications: bottle labels, packaging seals, logistics labels

2. ‌Film-based materials‌

• ‌BOPP (Biaxially Oriented Polypropylene)‌: high transparency and moisture resistance; commonly used for food packaging labels

• ‌PET (Polyester)‌: wear-resistant and heat-resistant; ideal for high-end electronic product labels or outdoor use

• ‌PVC (Polyvinyl Chloride)‌: good flexibility but lower environmental compatibility; gradually being replaced

• ‌PE (Polyethylene)‌: excellent flexibility; often used for soft packaging labels

3. ‌Specialty materials‌

• ‌Aluminum foil paper‌: used for premium labels requiring metallic luster, such as wine or pharmaceutical packaging; requires special ink to prevent cracking

• ‌Holographic paper / foil-laminated materials‌: enhance visual appeal; commonly used in gift or cosmetic labels

• ‌Water-activated color-changing paper‌: provides anti-counterfeiting functionality (e.g., turns red when wet); used in warranty labels for electronics

4. ‌Eco-friendly and security materials‌

• Biodegradable substrates combined with water-based inks align with green printing trends

• Integration of invisible inks, micro-text, or RFID chips enhances security

2. Key Parameters for Material Selection

• ‌Thickness compatibility with printing plates‌:
  High-precision label printing typically uses 1.14mm-thick photopolymer plates, best paired with label stock weighing 60–240g/m².

• 1.14–1.7mm plates: suitable for high-resolution label printing

• Over 3mm plates: mainly used for coarse printing like corrugated cardboard

• ‌Ink compatibility‌:
  Flexo printing commonly uses water-based or UV inks, requiring materials with moderate surface tension (e.g., BOPP at 31–38 dynes) to ensure good adhesion