Transfer Sheet Protective Layer Burr Resistance

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Solution Overview

Problem

Transfer sheets currently face issues with burr generation and wear resistance, as existing rigid film layers with inorganic particles lack sufficient hardness and flexibility, leading to inferior performance in preventing burr formation and crack generation on transferred materials.

Innovation Solution

A transfer sheet is produced with a protecting layer formed by mixing an actinic radiation-curable resin composition with colloidal silica particles bearing free silanol groups, which undergo heat cross-linking with a polyfunctional isocyanate, enhancing the layer's resistance to burr generation and wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid membrane layer containing inorganic particles is added to improve wear resistance and burr resistance, then the protecting layer becomes harder, but the layer loses flexibility and cannot follow curved surfaces, causing cracks

Engineering Contradiction:
Improvewear resistanceVSAvoidflexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent changes the physical and chemical parameters of the protecting layer by using a two-stage curing process: first UV irradiation to form a preliminary cross-linked structure, then heat treatment to enable the layer to follow curved surfaces. This parameter change allows the layer to maintain both hardness for wear resistance and flexibility to adapt to curved surfaces without cracking

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite protecting layer combining organic resin components (polymer with hydroxyl groups, polyfunctional isocyanate) with inorganic particles (colloidal silica). This composite structure provides both the hardness needed for wear resistance and the flexibility required to follow curved surfaces, resolving the contradiction between strength and adaptability

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If the protecting layer is made harder to improve burr resistance, then the layer can prevent burr generation, but it cannot neatly cut off at the partition line, causing burr formation

Engineering Contradiction:
Improveburr resistanceVSAvoidcutting precision
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies preliminary UV irradiation to the protecting layer before final heat treatment. This preliminary action creates an initial cross-linked structure that provides sufficient hardness for burr resistance while maintaining the flexibility needed for precise cutting at partition lines, thereby preventing burr formation during the releasing process

Inventive Principle:
Principle #10Preliminary action

3Strength

If colloidal silica particles are used instead of conventional inorganic particles, then the protecting layer achieves both wear resistance and flexibility, but a heat cross-linking process must be added

Engineering Contradiction:
Improvewear resistanceVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges two curing processes (UV irradiation and heat treatment) into a sequential two-stage process. The UV irradiation provides preliminary cross-linking for structural formation, while the subsequent heat treatment enables the layer to follow curved surfaces. This merging of processes achieves both wear resistance and flexibility without requiring separate independent steps

Inventive Principle:
Principle #5Merging (Combining)

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 resulting transfer sheet exhibits improved resistance to burr generation and wear resistance, allowing for neat transfer layer cutting and prevention of cracks on curved surfaces, while maintaining flexibility and transparency.

Implementation Method 1

an actinic radiation curable resin composition comprising a polymer with a (meth)acrylic equivalent of 100 to 300 g/eq, a hydroxyle value of 20 to 500, and a weight-average molecular weight of 5000 to 50000

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

colloidal silica particles bearing free silanol groups on their surface... a polyfunctional isocyanate... producing a product of heat cross-linking among the polymer, the polyfunctional isocyanate, and the colloidal silica particles by heating the protecting layer

Methodology Applied
Scientific EffectHeat cross-linking: Chemical Bonding

Data Source

PatentEP2221175B1Process for production of transfer sheets excellent in the resistance to burr generation and transfer sheets
Publication Date: 2013.10.23 NISSHA PRINTING CO LTD
  • EP2221175B1 patent drawingFigure 1~2
  • EP2221175B1 patent drawingFigure 3~4
  • EP2221175B1 patent drawingFigure 5

AI summary

A process for the production of a transfer sheet provided with a protective layer which is more excellent in the resistance to burr generation and in wear resistance and which is also excellent in the ability to follow the curved surface of a substrate; and a transfer sheet (1) comprising a releasable support sheet (11) and a transfer layer (20) formed on the support sheet (11), wherein the transfer layer (20) has a protective layer (21). The protective layer (21) is formed by heating a protective layer precursor (which is in an uncrosslinked state) made of a material prepared by mixing an actinic-radiation-curable resin composition comprising both a polymer (A) having a (meth)acrylic equivalent of 100 to 300g/eq, a hydroxyl value of 20 to 500, and a weight-average molecular weight of 5000 to 50000 and a polyfunctional isocyanate with colloidal silica particles bearing free silanol groups on the surfaces and contains a product of heat crosslinking among the polymer (A), the polyfunctional isocyanate, and the colloidal silica particles.