Wet-Shrink Paper Packaging for Heat-Free Article Binding

Solution Overview

Problem

Plastic shrink-wrap is unsustainable and requires high energy for heating, while paper lacks the ability to shrink upon heating, limiting its use as a versatile packaging material for irregularly shaped articles.

Innovation Solution

A paper packaging material with specific properties, including a wet shrinkage of at least 3% in the CD direction, enhanced fiber length, and balanced tensile stiffness, is used to wrap articles by wetting and drying, leveraging humidity-induced dimensional changes for shrinkage without heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plastic shrink-wrap is used to bundle multiple products, then the wrapping material provides high shrinkage and stability when heated, but it generates CO2 and requires high energy consumption

Engineering Contradiction:

Improvewrapping stabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical state parameter of the packaging material from dry to wet, enabling paper to exhibit shrinkage properties similar to plastic. By controlling the moisture content and wetting process, the paper achieves dimensional changes without requiring thermal energy, thus eliminating the need for heating while maintaining wrapping effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal heating mechanism with a moisture-based mechanism. Instead of using heat to cause plastic shrinkage, the invention uses water absorption and capillary forces to enable paper shrinkage, substituting a mechanical/chemical process for a thermal one, thereby reducing energy consumption and CO2 emissions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-generated harmful factors

If paper is used as a wrapping material, then it is sustainable and recyclable, but it lacks the ability to shrink when heated unlike plastic

Engineering Contradiction:

ImproveCO2 emissionVSAvoidshrinkage capability

Core Design Contradiction:

Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent changes the physical state parameter of the packaging material from dry to wet, enabling paper to exhibit shrinkage properties similar to plastic. By controlling the moisture content and wetting process, the paper achieves dimensional changes without requiring thermal energy, thus eliminating the need for heating while maintaining wrapping effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal heating mechanism with a moisture-based mechanism. Instead of using heat to cause plastic shrinkage, the invention uses water absorption and capillary forces to enable paper shrinkage, substituting a mechanical/chemical process for a thermal one, thereby reducing energy consumption and CO2 emissions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If paper is wetted and dried to achieve shrinkage, then it binds articles together, but the paper may tear during the drying process

Engineering Contradiction:

Improvebinding strengthVSAvoidtensile strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies a size agent to the paper before wetting, which pre-treats the paper structure to prevent tearing during the subsequent wetting and drying process. This preliminary chemical treatment strengthens the paper fibers, allowing them to withstand the mechanical stress of shrinkage without tearing, thus enabling successful wrapping of irregularly shaped articles

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4603639A1Packaging material and method of wrapping articles

Publication Date: 2025.08.20 SMURFIT KAPPA SERVICES LTD

AI summary

The present invention provides a packaging material comprising paper having a wet shrinkage in the CD direction of at least 3% and a method of wrapping articles with said packaging material, wetting the packaging material, wrapping said articles with said wetted packaging material, and drying the packaging material such that it shrinks to tightly bind the wrapped articles.