Thermal Transfer Sheet Primer Layer Adhesion

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Solution Overview

Problem

Current thermal transfer sheets face challenges in accurately removing a portion of the transfer layer from an intermediate transfer medium without reverse transfer of the peel-off layer, especially when high energy is applied, particularly with thick or durable transfer layers.

Innovation Solution

A thermal transfer sheet with a primer layer containing specific materials such as inorganic particles, polyvinyl pyrrolidone type resin, polyester type resin, or polyurethane type resin, which enhances the adhesiveness between the substrate and the peel-off layer, preventing reverse transfer even under increased energy conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high energy is applied to remove thick or durable transfer layers, then the transfer layer removal effectiveness is improved, but reverse transfer of the peel-off layer occurs

Engineering Contradiction:
Improvetransfer layer removal accuracyVSAvoidreverse transfer of peel-off layer
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A primer layer is introduced as an intermediary between the substrate and the peel-off layer. This primer layer serves as a mediator that enhances the adhesive bond strength, preventing the peel-off layer from transferring to the intermediate transfer medium even when high energy is applied for removing thick or durable transfer layers.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal transfer sheet is constructed as a composite structure comprising a substrate, a primer layer with specific adhesive materials, and a peel-off layer. This composite structure combines materials with different functions: the substrate provides structural support, the primer layer provides enhanced adhesion, and the peel-off layer enables selective removal of the transfer layer.

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If the adhesiveness between substrate and peel-off layer is improved by easily-adhesive treatment, then reverse transfer is reduced, but the structure becomes more complex

Engineering Contradiction:
Improvereverse transfer of peel-off layerVSAvoidsubstrate structure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The adhesive system is segmented into a dedicated primer layer that is separate from both the substrate and the peel-off layer. This segmentation allows the primer layer to specialize in providing adhesive functionality, while the substrate can maintain its structural simplicity. The primer layer acts as an independent functional component that bridges the substrate and peel-off layer.

Inventive Principle:
Principle #1Segmentation

3Strength

If a primer layer with specific materials is added to prevent reverse transfer, then adhesiveness is improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveadhesiveness between substrate and peel-off layerVSAvoidthermal transfer sheet manufacturing
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The invention specifies particular material parameters for the primer layer, such as using resins with glass transition temperatures of 60°C or higher (e.g., polyvinyl pyrrolidone type resin, polyester type resin, polyurethane type resin) or inorganic particles with specific particle sizes. These parameter specifications ensure optimal adhesive performance while providing clear manufacturing guidelines that simplify the production process.

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 ensures accurate removal of the transfer layer without reverse transfer, maintaining high adhesiveness between the substrate and peel-off layer, regardless of the energy applied, thus improving the peel-off property.

Implementation Method 1

a primer layer containing at least one of (1) inorganic particles derived from sol-based inorganic particles having a primary particle size of 200 nm or less, (2) scale-like inorganic particles, (3) a polyvinyl pyrrolidone type resin having a glass-transition temperature (Tg) of 60°C or more, (4) a polyester type resin having a glass-transition temperature (Tg) of 60°C or more, (5) a polyurethane type resin having a thermal melting temperature of 100°C or more

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

energy is applied to the other surface of the substrate of the heat transfer sheet, and the transfer layer corresponding to the region to which the energy has been applied is removed

Methodology Applied
Scientific EffectThermal bonding: Heating

Data Source

PatentEP3279002B1Thermal transfer sheet
Publication Date: 2020.05.06 DAI NIPPON PRINTING CO LTD
  • EP3279002B1 patent drawingFigure 1~3
  • EP3279002B1 patent drawingFigure 4~5

AI summary

There is provided a thermal transfer sheet by means of which a transfer layer can be accurately removed without being influenced by the conditions under which the transfer layer of the intermediate transfer medium is removed by means of a peel-off layer. In a thermal transfer sheet 10 having a peel-off layer 4, the above problem is solved by the thermal transfer sheet 10, wherein a primer layer 2 and a peel-off layer 4 are provided in this order on a substrate 1 and the primer layer 2 is allowed to contain at least one of: (1) inorganic particles derived from sol-based inorganic particles having a primary particle size of 200 nm or less, (2) scale-like inorganic particles, (3) a polyvinyl pyrrolidone type resin having a glass-transition temperature (Tg) of 60°C or more, (4) a polyester type resin having a glass-transition temperature (Tg) of 60°C or more, (5) a polyurethane type resin having a thermal melting temperature of 100°C or more, (6) a resin formed by curing a thermoplastic resin having a glass-transition temperature (Tg) of 40°C or more, and (7) a resin formed by curing a polyvinyl alcohol type resin.