What Material is Coated Paper?

Coated paper is a composite material consisting of a base paper substrate and a plastic coating layer. The base paper substrate typically uses kraft paper or white cardboard, with a thickness of 60-250 g/m², which provides printability and stiffness. The plastic coating layer is mostly a polyethylene (PE) or polypropylene (PP) film, with a thickness of approximately 10-50 microns. PE coating is flexible and suitable for food packaging; PP coating is heat-resistant (above 120°C) and suitable for microwave heating scenarios. Coated paper has water and oil resistance properties (with a water vapor transmission rate of less than 5 g/m²·24h) and heat-sealability (with a sealing strength of 3-5 N/15mm).

The adhesion effect of coated paper depends on the type of adhesive tape and surface treatment. Ordinary BOPP tape has relatively weak adhesive force (with a peel strength of approximately 1.2 N/cm), while cloth-based tape has an improved adhesive force of 2.5 N/cm, and acrylic foam tape boasts a high peel strength of 4-6 N/cm. Surface treatment via corona discharge (with a dyne value ≥ 38 mN/m) can significantly enhance the adhesiveness.

In the field of paper bag manufacturing, coated paper plays a pivotal role as a key raw material. Understanding the classification of coated paper is crucial for paper bag manufacturers like Dingliteng Packaging to accurately select suitable materials, optimize product performance, and meet diverse market demands. Simply put, coated paper is produced by coating plastic pellets onto the surface of paper using a casting machine to form a thin plastic film. This process endows the paper with numerous properties such as moisture resistance, oil resistance, and airtightness, greatly expanding the application scope of paper.