Self-Crosslinking Acrylic Ink for Adhesive Compatibility

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Solution Overview

Problem

Reverse printed inks and coatings used in laminate structures face challenges with adhesive compatibility, where the adhesive can degrade the ink, leading to migration and loss of visual properties, especially in applications like food and medicine packaging, where regulatory limits for migratable components are stringent.

Innovation Solution

A laminate structure incorporating a self-crosslinking acrylic polymer with a glass transition temperature (Tg) of 0°C or greater, combined with a coalescent and water, applied to a polymeric substrate, which is then bonded with a polyurethane adhesive, ensuring the ink's resistance to degradation and maintaining adhesive properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a polyurethane adhesive is used to bond substrates in a laminate structure, then the substrates are effectively bonded together, but the adhesive may degrade the ink layer, causing it to run, bleed, or smudge

Engineering Contradiction:
Improveadhesive bonding strengthVSAvoidink layer integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the ink layer by incorporating specific polymers (polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose) and additives (surfactants, plasticizers) in controlled concentrations. These parameter changes enable the ink to maintain compatibility with polyurethane adhesives while preventing degradation, bleeding, or smudging, thus resolving the contradiction between bonding strength and ink integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink layer system combining multiple polymers (PVDF, PVA, CMC) with specific additives to form a chemically stable composite material. This composite structure provides both adhesive compatibility and resistance to polyurethane adhesive degradation, allowing the ink layer to remain intact while enabling strong substrate bonding.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the ink layer is made more resistant to adhesive degradation, then ink integrity is maintained, but the adhesive bonding capability may be compromised

Engineering Contradiction:
Improveink layer stabilityVSAvoidadhesive bonding capability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent adjusts the chemical parameters of the ink layer by controlling the molecular weight, concentration, and composition of polymers and additives. These parameter modifications create an ink layer that is both resistant to adhesive degradation and compatible with polyurethane adhesives, maintaining both ink stability and bonding capability simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different functional properties to different components of the ink layer: PVDF provides adhesive compatibility, PVA provides bonding capability, and CMC provides stability. This local quality differentiation within the composite ink layer allows each component to fulfill its specific function without compromising the overall system performance.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If conventional inks are used in reverse printing, then the printing process is simple, but the ink components can migrate into the package to contaminate packaged goods

Engineering Contradiction:
Improveprinting process simplicityVSAvoidink component migration
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent develops a composite ink formulation combining PVDF, PVA, CMC, and functional additives that creates a chemically stable barrier layer. This composite structure prevents ink component migration into packaged goods while maintaining printing simplicity, thus resolving the contradiction between ease of manufacture and contamination prevention.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent uses water-soluble polymers and additives that can be easily removed or degraded if necessary, providing a safe alternative to conventional inks. The ink layer can be simplified for printing purposes while the composite formulation ensures no harmful migration occurs, effectively treating the ink as a temporary, safe barrier during the product lifecycle.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 described laminate structure effectively prevents ink migration and maintains adhesive strength, even when exposed to detergents, ensuring compliance with regulatory standards and maintaining visual properties.

Implementation Method 1

an ink or coating composition comprising a self-crosslinking acrylic polymer

Methodology Applied
Scientific EffectSelf-crosslinking: Chemical Bonding

Implementation Method 2

a coalescent

Methodology Applied
Scientific EffectCoalescence: Coagulation

Implementation Method 3

an adhesive bonding the first substrate to the second substrate

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3794082B1Film lamination inks
Publication Date: 2021.11.10 SUN CHEMICAL CORP

AI summary

Described herein are printed laminates. The laminates include a first substrate having an applied layer of an ink or coating composition that includes a self-crosslinking acrylic polymer having has a glass transition temperature of 0°C or greater, a coalescent, and water; a second substrate positioned to configure the applied layer between the first substrate and the second substrate; and an adhesive bonding the first substrate to the second substrate. Also described is a process for making such laminates. In one aspect, the applied layer of ink is a reverse printed layer, in which the applied ink layer is highly compatible with the adhesive with which it comes in contact.