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Print Directly to Plastic with Eastman Adhesion Promoters

Flexible Packaging Requires Higher-Performing Ink

Advancement in packaging materials has led to a surge in flexible packaging technology. Packaging applications that were once restricted to rigid materials, such as glass or metal, are now done with flexible, olefin-based substrates, such as polyethylene, polypropylene, and PET. While these substrates serve as excellent packaging films, owing to their structural and barrier properties, they are often difficult to print on because they have low surface energy. The rise in flexible packaging and low–surface energy substrates that require printing has driven a need for inks that can be printed directly to a variety of materials. 

Adhesion-Promoting Additives for Inks 

Eastman's polyolefin adhesion promoters have traditionally been used in primers to improve coating adhesion to a thermoplastic olefin or metal surface. This same technology, which has been used for decades in automotive and architectural coating applications, is also available as a stir-in additive for solvent- and water-based printing inks. 
 
With UV-curable inks becoming more prevalent in the marketplace, Eastman’s adhesion promoters can help mitigate the common issue of shrinking. While UV offers advantages in sustainability and fast cure speeds, these fast curing speeds can lead to potential lateral shrinkage of ink films, causing durability and quality issues. When used as primers, Eastman's adhesion promoters impart increased adhesion of the ink system onto the substrate, which is critical for mitigating shrinkage and enabling UV inks to be applied effectively on various substrates. 

Adhesion Promoter Grades 
 
Eastman has developed several adhesion promoters suitable for a variety of ink formulations. Grades designed as blend-in additives are listed below for solvent-based and water-based systems. When formulated into primers, these grades are also effective for improving the adhesion of UV-curable inks. With recent concerns around environmental health and safety, Eastman has also released APEO-free and halogen-free grades such as AP 550-1, Advantis™ 510W, and CP 377W for formulators looking to get ahead of tightening global regulations. 

Solvent-Based Grades

Water-Based Grades

Formulation Considerations

When formulating Eastman Polyolefin Adhesion Promoters into printing ink, testing should be done to ensure compatibility with the solvent and resin systems. While the recommended addition rates above are a good starting point, testing should be done to determine the amount of adhesion promoter needed to achieve optimal adhesion without affecting dry film properties. 
 

Summary 

Adhesion promoters and primers have become increasingly required to ensure good ink adhesion as the packaging industry shifts away from using rigid materials, such as glass, hard plastic, and metal, in favor of low–surface energy materials, such as those used in flexible packaging. Eastman's adhesion promoters present a variety of options for water-based, solvent-based, and UV-curable ink formulators. Click below to take the next steps and request a sample today. 

 

 

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