Relief Transfer Foil Layer Structure for Heat-Resistant Shaping

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Solution Overview

Problem

Existing transfer foils face challenges in achieving high accuracy of relief structure shaping, resistance to heat and pressure, and transferability due to the contradiction of physical properties, leading to issues such as burrs, cracks, and poor durability.

Innovation Solution

A transfer foil configuration comprising a first resin layer of acrylic resin with a glass transition temperature of 95°C or higher, a second resin layer composed of a mixture of acrylic resin and urethane-crosslinked cellulose ester resin with a higher melting point, and a relief forming layer with a lower melting point, ensuring compatibility and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transfer foil material with high heat resistance and impact resistance is used to prevent damage during transfer and attachment, then the durability is improved, but the transferability deteriorates leading to burrs and chips

Engineering Contradiction:
ImprovedurabilityVSAvoidtransferability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The transfer foil is divided into multiple functional layers: a first resin layer (acrylic resin with Tg ≥95°C) providing heat resistance and durability, a second resin layer providing intermediate properties, and a relief forming layer with the optical pattern. This segmentation allows each layer to optimize for its specific function without compromising overall performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses composite resin materials with specific glass transition temperatures and mechanical properties in different layers. The first resin layer uses acrylic resin with Tg ≥95°C for heat resistance, while the second resin layer uses a different composition to balance transferability and structural support, creating a composite structure that achieves both durability and transferability

Inventive Principle:
Principle #40Composite materials

2Reliability

If significantly high temperature and pressure are applied to shape the relief structure, then the heat resistance and impact resistance are improved, but the accuracy of relief structure shaping deteriorates

Engineering Contradiction:
Improveheat resistanceVSAvoidaccuracy of relief structure shaping
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent controls the glass transition temperature parameter of the resin materials to be ≥95°C, which allows the relief structure to be formed at moderate temperatures without excessive thermal deformation. This parameter optimization enables shaping at lower temperatures while maintaining heat resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The relief forming layer is separated from the support structure layers, allowing the relief pattern to be formed with high precision using a metal stamp or mold at controlled temperatures, while the underlying resin layers provide the necessary heat resistance without interfering with the shaping accuracy

Inventive Principle:
Principle #1Segmentation

3Reliability

If a cellulose-based material with high melting point is used in the release layer to prevent cracks, then the heat resistance is improved, but the effectiveness in hot-stamping thermal pressure transfer is insufficient

Engineering Contradiction:
Improveheat resistanceVSAvoidtransfer efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The release layer uses a composite material system where the first resin layer (acrylic resin with Tg ≥95°C) provides heat resistance comparable to cellulose-based materials, while the second resin layer and relief forming layer use materials optimized for thermal pressure transfer. This composite approach achieves both heat resistance and transfer efficiency

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material composition parameter to use acrylic resin with controlled glass transition temperature (≥95°C) instead of traditional cellulose-based materials. This parameter change maintains the high melting point and heat resistance while improving compatibility with thermal pressure transfer processes

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 solution achieves high accuracy of relief structure shaping, resistance to heat and pressure, and improved transferability by minimizing thermal stress and maintaining structural integrity during thermal pressure transfer.

Implementation Method 1

The first resin layer is composed of an acrylic resin having a glass transition temperature Tg of 95°C or higher

Methodology Applied
Scientific EffectGlass transition temperature:

Implementation Method 2

The second resin layer and the relief forming layer are composed of a mixture of the acrylic resin, and a cellulose ester resin in which some of hydroxyl groups are urethane crosslinked

Methodology Applied
Scientific EffectUrethane crosslinking:

Implementation Method 3

a relief structure exerting an optical effect such as diffraction

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP4390473B1Relief structure-bearing transfer foil
Publication Date: 2025.12.03 TOPPAN INC
  • EP4390473B1 patent drawingFigure 1
  • EP4390473B1 patent drawingFigure 2
  • EP4390473B1 patent drawingFigure 3

AI summary

A transfer foil separably supported by a support includes a first resin layer, a second resin layer, and a relief forming layer in this order from a side closer to the support. The first resin layer is composed of an acrylic resin having a glass transition temperature Tg of 95°C or higher. The second resin layer and the relief forming layer are composed of a mixture of the acrylic resin, and a cellulose ester resin in which some of hydroxyl groups are urethane crosslinked. The second resin layer has a higher melting point than the relief forming layer.