Thermosensitive Recording Material Back Layer Adhesion

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Solution Overview

Problem

Thermosensitive recording materials with synthetic paper or plastic film supports often experience peeling and curling issues due to adhesion problems between the support and the back layer, particularly when exposed to adhesives, which existing solutions fail to adequately address.

Innovation Solution

A thermosensitive recording material with a back layer composed of a core-shell acrylic resin and an oxazoline resin, or their reaction product, applied on a resinous support surface, enhancing adhesion, water resistance, and durability, and optionally including an antistatic agent and adhesive layer for improved stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a back layer is provided between a support and an adhesive layer to improve adhesion, then adhesion between layers is enhanced, but peeling occurs from the portion where adhesion is weakened due to migration of low molecular weight components

Engineering Contradiction:
Improveadhesion strengthVSAvoidpeeling resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the back layer by specifying a styrene-acryl copolymer with acid value of 200 or greater and Tg of 80°C or higher. These parameter changes create a back layer that is resistant to migration by low molecular weight components from the adhesive, thereby maintaining adhesion strength and preventing peeling over time.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material approach by combining specific polymers (styrene-acryl copolymer with high acid value and high Tg) with controlled filler content (5-50 mass%). This composite structure provides both strong adhesion to the support and resistance to adhesive migration, solving the peeling problem while maintaining layer bonding.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If synthetic paper or plastic film with higher smoothness is used as a support, then dimensional stability is improved, but curling of the thermosensitive recording material occurs

Engineering Contradiction:
Improvedimensional stabilityVSAvoidcurling
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The patent changes the surface property parameters of the support by specifying a wetting index of 0.03 N/m or more. This parameter change ensures proper wetting and adhesion of the back layer to the smooth synthetic paper or plastic film support, preventing curling while maintaining dimensional stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The back layer acts as an intermediary between the smooth support and the adhesive layer. By providing a back layer with high acid value and high Tg that adheres well to the smooth support surface, it prevents curling without compromising the dimensional stability of the synthetic paper or plastic film support.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If a back coat layer containing core-shell acrylic emulsion and inorganic pigment is provided to improve adhesion and water resistance, then adhesion is enhanced, but film forming ability and barrier properties are insufficient

Engineering Contradiction:
ImproveadhesionVSAvoidbarrier properties
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by specifying a styrene-acryl copolymer with acid value of 200 or greater and Tg of 80°C or higher, replacing the core-shell acrylic emulsion. This parameter change provides both strong adhesion and superior barrier properties, as the high acid value indicates high polarity and bonding capability, while the high Tg provides thermal stability and resistance to adhesive migration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite back layer combining styrene-acryl copolymer with controlled filler content (5-50 mass%). This composite structure provides both adhesion enhancement and improved barrier properties, as the polymer matrix with high acid value creates a dense, polar structure that resists penetration by low molecular weight components from the adhesive.

Inventive Principle:
Principle #40Composite materials

4Stability of the object's composition

If curing agent is used to enhance water resistance of cellulose base support, then water resistance is improved, but prevention of adhesion reduction due to organic material migration is not achieved

Engineering Contradiction:
Improvewater resistanceVSAvoidadhesion strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent changes the chemical composition by specifying a styrene-acryl copolymer with acid value of 200 or greater and Tg of 80°C or higher. These parameter changes create a back layer that provides both water resistance and resistance to adhesion reduction, as the high acid value indicates high polarity for water resistance, while the high Tg provides thermal stability to prevent migration-related adhesion loss.

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 provides excellent adhesion between the resinous support and the back layer, prevents peeling and curling, and maintains water resistance and stability even when an adhesive is applied, making it suitable for various applications.

Implementation Method 1

the back layer contains a core-shell acrylic resin and an oxazoline resin, or a reaction product thereof

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

a back layer which contains a core-shell acrylic resin and an oxazoline resin, or a reaction product thereof

Methodology Applied
Scientific EffectCrosslinking:

Implementation Method 3

low molecular weight components, such as a plasticizer, a tackifier (a tackiness imparting agent), and an emulsifier, contained in an adhesive used in an adhesive layer migrate into a back layer or a support

Methodology Applied
Scientific EffectBarrier properties:

Implementation Method 4

thermosensitive recording materials have the following advantages: (1) a simple image recording is realized only by a heating process

Methodology Applied
Scientific EffectThermal reaction:

Data Source

PatentEP2675626B1Thermosensitive recording material
Publication Date: 2016.09.14 RICOH CO LTD

AI summary

To provide a thermosensitive recording material, which contains: a support; a thermosensitive recording layer provided on one surface of the support; and a back layer provided on the other surface of the support, wherein the support has a surface formed of a resin, and wherein the back layer contains a combination of a core-shell acrylic resin and an oxazoline resin, or a reaction product thereof, or both thereof.