Polyamide-EAA Primer Coating for High-Speed Digital Press Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Newer high-speed digital presses pose challenges for ink transfer and adhesion to substrates, as existing primer coatings are not effective in ensuring proper adhesion and ink transfer without additional primers or precoatings.
Innovation Solution
An aqueous dispersion comprising 50-70% polyamide, 10-20% polyurethane, and 20-40% ethylene acrylic acid copolymer is applied directly to substrates, providing a primer layer with less than 1% non-aqueous plasticizers and organic solvents, which enhances adhesion and ink transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing primer coatings based on ethylene-acrylic acid copolymers are used, then adhesion enhancement is achieved, but ink transfer and adhesion to substrates deteriorate in high-speed digital presses
Solution Approach 1:
The patent combines ethylene-acrylic acid copolymer with polyamide in a specific weight ratio (30-70% copolymer, 70-30% polyamide) to create a composite primer coating. This composite formulation leverages the adhesion properties of the copolymer while the polyamide component ensures proper ink transfer and prevents blocking, resolving the contradiction between adhesion enhancement and ink transfer reliability in high-speed digital presses.
2Reliability
If additional primers or precoatings are applied to improve ink transfer, then ink transfer improves, but device complexity and coating layers increase
Solution Approach 1:
The patent merges the functions of multiple coatings (primer and precoat) into a single composite primer coating formulation. By incorporating both ethylene-acrylic acid copolymer for adhesion and polyamide for ink transfer properties within one coating layer, the need for separate additional primers or precoatings is eliminated, simplifying the overall coating structure while maintaining reliable ink transfer.
3Ease of manufacture
If conventional primer formulations are used, then manufacturing simplicity is maintained, but adhesion and ink transfer performance deteriorate in high-speed digital printing
Solution Approach 1:
The patent modifies the chemical composition parameters of the primer coating by specifying precise weight percentage ranges of polyamide (30-70%) and ethylene-acrylic acid copolymer (70-30%). This parameter optimization ensures both components contribute effectively to the coating's performance, achieving reliable adhesion and ink transfer in high-speed digital printing while maintaining straightforward manufacturing processes.
Data Source
AI summary
Primer coatings including an aqueous dispersion having a mixture of a polyamide and a copolymer of ethylene and acrylic acid are provided for use on a variety of substrates. In various embodiments, the aqueous dispersion is substantially free of non-aqueous plasticizers and organic solvents. Also provided is a method of coating a substrate, the method including applying an aqueous dispersion to the substrate and drying the aqueous dispersion on the substrate to form a coating on the substrate. The disclosure also describes a substrate coated with a primer layer including a mixture of a polyamide and a copolymer of ethylene and acrylic acid.