Transparent In-Mold Label Laminate That Resists Silicone Transfer

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Solution Overview

Problem

Existing in-mold labels face issues with reduced adhesive strength due to silicone transfer from the protective layer to the heat-sealable resin layer, and they lack transparency for aesthetic purposes.

Innovation Solution

A laminate comprising a substrate layer, a heat sealing layer, and a coating layer, where the coating layer contains thermoplastic resin particles with an average particle size of 0.01 to 0.80 µm and a (meth)acrylic acid-based copolymer with a polar group, enhancing adhesiveness and transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a protective layer is disposed on the printed layer to prevent scratches and stains, then the printed layer is protected, but silicone may transfer from the protective layer to the heat-sealable resin layer, reducing adhesiveness

Engineering Contradiction:
Improvescratch and stain preventionVSAvoidadhesiveness
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent introduces a release layer as an intermediary between the protective layer containing silicone and the heat-sealable resin layer. This release layer prevents direct contact between silicone and the adhesive layer, thereby blocking the transfer of silicone that would reduce adhesiveness. The release layer acts as a mediator that allows the protective layer to maintain its scratch and stain prevention function while preventing harmful silicone transfer to the adhesive interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If the in-mold label is made transparent for aesthetic purposes, then appearance is improved, but adhesive strength may be compromised

Engineering Contradiction:
ImprovetransparencyVSAvoidadhesive strength
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The patent applies local quality by making only the necessary layers transparent while maintaining the functional integrity of each layer. The substrate layer and heat-sealable resin layer are made transparent for aesthetic purposes, while the release layer and protective layer can have different optical properties optimized for their specific functions. This allows the label to achieve transparency where needed without compromising the adhesive strength provided by the heat-sealable resin layer.

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If the average particle size of thermoplastic resin particles is reduced to enhance transparency, then transparency is improved, but the coating layer structure becomes more complex

Engineering Contradiction:
ImprovetransparencyVSAvoidcoating layer structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the average particle size of thermoplastic resin particles within the specific range of 0.01 to 0.80 µm. This parameter optimization achieves transparency enhancement while maintaining manageable coating layer structure. The patent further optimizes the glass transition temperature and other parameters of the thermoplastic resin particles to achieve the desired balance between transparency and structural complexity.

Inventive Principle:
Principle #35Parameter changes

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 laminate maintains adhesiveness to resin containers despite silicone transfer and provides transparency, facilitating easy removal during high-temperature recycling processes.

Implementation Method 1

An in-mold label that is thermally fused through heat from molding to the surface of the resin container formed by blow molding

Methodology Applied
Scientific EffectThermal fusion: Melting

Implementation Method 2

a coating layer, wherein the coating layer contains thermoplastic resin particles and a (meth)acrylic acid-based copolymer

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP4670972A1laminate
Publication Date: 2025.12.31 YUPO CORP
  • EP4670972A1 patent drawingFigure 1
  • EP4670972A1 patent drawingFigure 2A~2B
  • EP4670972A1 patent drawingFigure 3

AI summary

Provided is a laminate that enhances the adhesiveness of the laminate to a container even if silicone is transferred from a protective layer side to a heat sealing layer side, and furthermore has transparency. The laminate is an in-mold label comprising a substrate layer, a heat sealing layer, and a coating layer, wherein the coating layer comprises thermoplastic resin particles and a (meth)acrylic acid-based copolymer, the thermoplastic resin particles have an average particle size of 0.01 to 0.80 µm, and the (meth)acrylic acid-based copolymer has a polar group.