Thermal Lamination Primer for Flexible Packaging Bonding

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Solution Overview

Problem

Existing laminated flexible packaging materials face issues such as delamination during thermal processes like pasteurization and retort, and printed images can discolor due to adhesive curing times, which hinder the efficiency of food packaging and extend production cycles.

Innovation Solution

A process involving a first flexible substrate coated with poly(acrylic acid) or poly(methacrylic acid) and a liquid electrophotographic printing ink composition, combined with a thermally activatable laminating material, allows for immediate lamination at temperatures above 50°C, eliminating the need for curing time and ensuring strong bond strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional adhesive coatings are used for lamination, then lamination bond strength can be achieved, but curing time is required which extends production cycles

Engineering Contradiction:

Improvelamination bond strengthVSAvoidcuring time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the chemical parameters of the adhesive system by using a polyacid primer (polyacrylic acid or poly methacrylic acid) that reacts with basic groups in the thermally activatable laminating material. This chemical modification enables immediate bonding without curing time, as the reaction occurs spontaneously upon contact between the acid primer and basic material groups.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the time-dependent mechanical curing process with an immediate chemical reaction mechanism. Instead of relying on gradual adhesive curing, the system uses a primer-based chemical reaction that occurs instantly upon lamination, substituting the mechanical/time-based curing system with a chemical instantaneous bonding system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If thermal processes like pasteurization and retort are applied, then food safety is improved, but delamination may occur during these processes

Engineering Contradiction:

Improvefood safetyVSAvoidlamination stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the thermal parameters of the lamination system by selecting a thermally activatable laminating material with specific thermal properties. The material is designed to remain stable and maintain bond strength at pasteurization and retort temperatures, while the polyacid primer ensures consistent bonding performance across this temperature range, preventing delamination during thermal food safety processing.

Inventive Principle:

Principle #35Parameter changes

3Loss of information

If printed images are used on flexible packaging, then product information and branding are provided, but images can discolor during thermal processes

Engineering Contradiction:

Improveimage integrityVSAvoidthermal process temperature

Core Design Contradiction:

Loss of informationVSTemperature

Solution Approach 1:

The patent introduces a polyacid primer as an intermediary layer between the printed image and the thermally activatable laminating material. This primer acts as a protective mediator that prevents direct thermal contact between the heat and the printed image, thereby preventing discoloration while still allowing thermal processes to proceed for food safety purposes.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This approach results in a flexible packaging material with zero cure time, maintaining bond strength and image integrity through thermal lamination, suitable for applications like pasteurization and retort, while streamlining production.

Implementation Method 1

contacting, under conditions of temperature of at least 50° C., the surface of the second flexible substrate on which the thermally activatable laminating material is deposited with the surface of the first flexible substrate printed with the liquid electrophotographic printing ink composition

Methodology Applied

Scientific EffectThermal activation: Heating

Implementation Method 2

providing a first flexible substrate coated with a primer comprising poly(acrylic acid) and/or poly(methacrylic acid)

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS11141962B2Immediate and high performance flexible packaging applications using thermal lamination and new primer technology

Publication Date: 2021.10.12 HP INDIGO BV

AI summary

A process for preparing a flexible packaging material (6) by laminating at a temperature greater or equal to 50° C. a printed substrate coated with a primer (4) comprising poly(acrylic acid) and/or poly(methacrylic acid) with another substrate coated with a thermal active material (2), to prepare a high performance flexible packaging multilayer material (6) showing improved shelf-life, without requiring curing stage of intermediate layers.