Polyurethane
Ink Binder is one of the most crucial and widely used materials in the modern flexible packaging industry. As the "skeleton" and "soul" of the ink, it plays a decisive role in the quality, safety and functionality of the entire packaging printed matter. Its core functions are mainly reflected in the following aspects:
1. Excellent adhesion and wide applicability
There are various types of base materials for flexible packaging, including polyethylene (PE), polypropylene (BOPP, CPP), polyester (PET), nylon (NY), and aluminum-coated film, etc. These materials have different surface properties and significant differences in polarity. Polyurethane binders, due to their highly designable molecular structure, can be well wetted and adhered to various film surfaces by adjusting the formula, forming a firm ink layer. This is the foundation for ensuring that the ink does not fall off or peel off during subsequent processing, such as bag-making, transportation, and sales.
2. Excellent printability and film-forming performance
Polyurethane binder can endow ink with excellent leveling, transferability and printability, enabling the ink to perform well on high-speed printing machines with clear dots, bright colors and rich gradation. The ink film it forms is tough, highly glossy and wear-resistant, which can effectively protect the printed patterns and make the flexible packaging products more visually appealing on the shelves.
3. Outstanding composite performance
In the production of flexible packaging, the printed film usually needs to be combined with other films through adhesives to make composite materials with functions such as barrier properties and durability. Polyurethane binders have excellent compatibility with commonly used
Polyurethane Adhesive systems. During the high-temperature curing process, the molecules of the binder and the adhesive can interpenetrate and cross-link, forming an extremely strong "inch-glue" interface, avoiding fatal defects such as delamination and de-bonding after lamination, and ensuring the overall strength of the packaging bag.
4. Critical safety and patience
For food and drug packaging, safety is the primary prerequisite. The high-quality polyurethane binder formula is pure, with low odor and low migration. It can effectively prevent small molecule substances in the ink from migrating into the contents, ensuring food safety. Meanwhile, polyurethane ink film has excellent resistance, such as heat resistance, frost resistance, oil resistance, and chemical resistance, which can meet the strict packaging requirements of the contents (such as high-temperature cooking and greasy food), ensuring the reliability of the packaging during storage and circulation.
In conclusion, polyurethane ink binder is the core material for achieving exquisite printing, firm lamination and safety and reliability in flexible packaging. It acts like a bridge, firmly anchoring colors onto various films and closely collaborating with adhesives, ultimately creating high-performance flexible packaging products that not only catch consumers' eyes but also perfectly protect the contents, greatly promoting the development of the flexible packaging industry.
