Primer Composition for Digital Shrink Labels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing digital printing processes for shrink labels face challenges with adhesion of liquid toner inks, particularly on substrates treated with coatings or primers, which can interfere with seaming solutions and hinder recycling processes.
Innovation Solution
A primer composition comprising 60 wt % to 95 wt % aqueous polyurethane dispersion and 5.0 wt % to 40 wt % aqueous dispersion of a copolymer of one or more α-olefins and one or more acid-based monomers, applied without lane priming, facilitates adhesion of liquid toner inks and allows for strong bonding with seaming solutions, enabling seamless digital printing and recycling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lane priming is used to allow seaming solutions to penetrate, then seaming bond strength is improved, but printing process time increases and productivity decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the primer to include specific seaming solution penetration promoters that allow the seaming solution to penetrate through the primer layer without requiring lane priming. This enables full-surface priming while maintaining seam bond strength, eliminating the need for time-consuming lane priming operations and improving productivity.
Solution Approach 2:
The patent introduces intermediary substances (seaming solution penetration promoters) within the primer composition that act as mediators between the primer layer and seaming solution. These promoters enable the seaming solution to penetrate through the primer without compromising either the adhesion or the bond strength, allowing full-surface priming to proceed efficiently.
2Strength
If full body priming is applied to ensure good adhesion, then liquid toner adhesion is improved, but seaming solution penetration is hindered
Solution Approach 1:
The patent creates a composite primer material that combines adhesion promoters for liquid toner with seaming solution penetration promoters. This composite formulation allows the primer to simultaneously provide strong adhesion for liquid toner while maintaining permeability for seaming solution penetration, resolving the contradiction between full body priming and seaming solution penetration.
Solution Approach 2:
The patent applies different functional properties to different regions of the primer layer through local quality differentiation. The primer composition is designed with specific components that remain on the surface for toner adhesion while other components facilitate penetration in the seam areas, allowing both functions to coexist without conflict.
3Manufacturing precision
If primer is applied to enhance liquid toner adhesion, then print quality is improved, but label separation from container during recycling is hindered
Solution Approach 1:
The patent modifies the chemical composition and molecular weight parameters of the primer to use water-soluble or caustic-sensitive components. This allows the primer to provide excellent adhesion during the printing process but to dissolve or degrade quickly when exposed to hot caustic solutions during recycling, enabling easy label separation from the container without compromising print quality.
Solution Approach 2:
The patent creates a dynamic primer system that changes its properties based on environmental conditions. The primer maintains strong adhesion properties under normal printing and handling conditions but transforms into a soluble or degradable state when exposed to recycling conditions (hot caustic solutions), allowing easy separation while maintaining print quality during manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The primer composition ensures excellent printability and adhesion of liquid toner inks on digitally printed shrink labels, while maintaining strong bond strength with seaming solutions, allowing for efficient recycling of containers by enabling quick removal of labels in hot caustic solutions.
Implementation Method 1
The primers facilitate and enable the printability of substrates that have demonstrated difficulties when used in digital printing operations... the primer compositions do not interfere with the ability of a seaming solution to form a sufficiently strong bond
Implementation Method 2
the bond in the seam that is formed by the seam welding solvent must be strong enough to hold the sleeve of the shrink wrap film around the container... the primer compositions do not interfere with the ability of a seaming solution to form a sufficiently strong bond
Implementation Method 3
shrink wrap films... the films are printed with text, images, logos, etc. to provide a label for the packaged material in the container... forming a seam comprised of contacting edges of the substrate, one of which contacting edges is the at least one edge to which seaming solution is applied
Data Source
AI summary
Described are primer coatings, overprint varnishes, and seaming solution solutions for application to substrates such as those used to make wrap around and sleeve labels, particularly shrink wrap labels, which are used to label containers. The labels can be digitally printed with or without lane priming. With certain seaming solutions, the labels can be removed in the wash stage to enable the recycling of containers.