Propylene Substrate for Curl Suppression in Thermal Transfer Sheets

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Solution Overview

Problem

Conventional thermal transfer image-receiving sheets face challenges in achieving high-quality image formation while suppressing curling, as reducing the thickness of thermal insulation layers to minimize curling compromises heat resistance and cushioning properties, leading to printing quality issues and visibility of defects in the supporting member.

Innovation Solution

A front face side substrate with a layered structure comprising a substrate layer made of propylene-based polymer, calcium carbonate, and titanium oxide, along with a modified propylene-based polymer front face side layer and a propylene-based polymer rear face side layer, is introduced between the supporting member and the receiving layer, enhancing heat resistance, cushioning, and masking properties to maintain image quality even when the substrate is made thinner.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the thickness of the thermal insulation layer is reduced to suppress curling, then the occurrence of curling is reduced, but the heat resistance and cushioning properties are compromised, leading to poor image formation quality

Engineering Contradiction:
ImprovecurlingVSAvoidimage formation quality
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The substrate is divided into multiple functional layers: a supporting member layer, a thermal insulation layer, and a receiving layer. This segmentation allows each layer to be optimized independently - the thermal insulation layer can be made thin to reduce curling while the receiving layer maintains sufficient thickness to ensure heat resistance and image quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the substrate structure are given different properties. The thermal insulation layer is positioned specifically between the supporting member and receiving layer to provide localized insulation, while the receiving layer provides localized cushioning and heat absorption where needed for image formation. This local optimization allows thin overall structure while maintaining functional performance.

Inventive Principle:
Principle #3Local quality

2Shape

If the thickness of the thermal insulation layer is reduced to suppress curling, then the occurrence of curling is reduced, but defects in the supporting member become visible, affecting appearance quality

Engineering Contradiction:
ImprovecurlingVSAvoidvisibility of defects
Core Design Contradiction:
ShapeVSObject-affected harmful factors

Solution Approach 1:

The receiving layer acts as an intermediary between the supporting member and the external environment. It provides a masking effect that conceals defects in the supporting member, while also functioning as the active layer for thermal transfer image reception. This intermediary layer solves both the curling suppression and defect masking requirements simultaneously.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Shape

If the thickness of the substrate is reduced to suppress curling, then the occurrence of curling is reduced, but the cushioning property is compromised, affecting image density

Engineering Contradiction:
ImprovecurlingVSAvoidcushioning property
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The cushioning function is segmented from the overall substrate thickness requirement. The receiving layer is specifically designed to provide cushioning through its material composition and structure, while the thermal insulation layer provides thermal management. This functional segmentation allows the substrate to be thin overall while maintaining sufficient cushioning in the receiving layer for high-quality image formation.

Inventive Principle:
Principle #1Segmentation

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

This configuration allows for high-quality image formation and effective curl suppression, concealing defects in the supporting member and maintaining image quality even when the thermal transfer image-receiving sheet is made thinner, thereby improving the overall printing quality and appearance.

Implementation Method 1

a thermal transfer sheet in which a colorant layer which includes sublimation type dye is provided on a substrate, and a thermal transfer image-receiving sheet in which a receiving layer is provided

Methodology Applied
Scientific EffectThermal energy absorption: Absorption (EM radiation)

Implementation Method 2

a thermal transfer image-receiving sheet in which a receiving layer is provided on a supporting member... a thermal insulation layer containing a hollow polymer is provided between the supporting member and the receiving layer

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3085548B1Surface substrate for heat transfer image reception sheet, and heat transfer image reception sheet
Publication Date: 2020.09.30 DAI NIPPON PRINTING CO LTD
  • EP3085548B1 patent drawingFigure 1~2
  • EP3085548B1 patent drawingFigure 3

AI summary

To provide a front face side substrate for a heat transfer image-receiving sheet, which is possible to perform high-quality image formation on a receiving layer even when the substrate is made thinner in order to suppress the occurrence of curling, and to provide a thermal transfer image-receiving sheet having the front face side substrate for thermal transfer image-receiving sheet. The above problem is solved by a front face side substrate (10) for a thermal transfer image-receiving sheet, the front face side substrate for the thermal transfer image-receiving sheet being provided between a supporting member and a receiving layer of the thermal transfer image-receiving sheet; the front face side substrate for the thermal transfer image-receiving sheet comprising a layered structure in which a front face side layer (3) is provided on one surface of a substrate layer (2) and a rear face side layer (1) is provided on another surface of the substrate layer (2); wherein the substrate layer comprises (A) a propylene-based polymer, (B) calcium carbonate, and (C) titanium oxide, and the weight of (A) being in the range of from not less than 70 % by weight to not more than 94.5 % by weight, the weight of (B) being in the range of from not less than 5 % by weight to not more than 28 % by weight, and the weight of (C) being in the range of from not less than 0.5 % by weight to not more than 3 % by weight, based on the assumption that the total weight of (A), (B) and (C) is 100 % by weight; the front face side layer (3) comprises a modified propylene-based polymer; and the rear face side layer (1) comprises a propylene-based polymer.