Thermosensitive Recording Material Protective Layer Flex Cracking

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Solution Overview

Problem

Conventional thermosensitive recording materials suffer from flex cracking and inadequate scratch resistance despite having high water, solvent, and heat resistance, due to the limitations of protective layers formed from conventional (meth)acrylamide copolymer emulsions.

Innovation Solution

A thermosensitive recording material with a protective layer composed of a mixture of hydrophobic and hydrophilic polymers and a non-crosslinking urea compound, which provides pliability and flexibility, reducing flex cracking and enhancing scratch resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional (meth)acrylamide copolymer emulsions are used for the protective layer, then water resistance, solvent resistance, and heat resistance are improved, but flex cracking occurs and scratch resistance deteriorates

Engineering Contradiction:
Improvewater resistance, solvent resistance, and heat resistanceVSAvoidscratch resistance and flex cracking resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention changes the chemical composition parameters of the protective layer by incorporating specific polymers (polyvinylidene chloride or carboxymethyl cellulose) and controlling the content of hydrophobic and hydrophilic polymer components. This parameter adjustment allows the protective layer to achieve both high resistance properties and improved flexibility, eliminating flex cracking while maintaining scratch resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The protective layer is formulated as a composite material system containing multiple components: hydrophobic polymer, hydrophilic polymer, and specific additives (polyvinylidene chloride or carboxymethyl cellulose). This composite structure combines the water and solvent resistance of conventional materials with the flexibility and scratch resistance provided by the composite formulation, resolving the contradiction between durability and flexibility

Inventive Principle:
Principle #40Composite materials

2Strength

If the protective layer is made more rigid to improve scratch resistance, then scratch resistance improves, but flex cracking increases

Engineering Contradiction:
Improvescratch resistanceVSAvoidflex cracking resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention optimizes the flexibility parameters of the protective layer by controlling the content ratios of hydrophobic and hydrophilic polymers and adding specific compounds (polyvinylidene chloride or carboxymethyl cellulose). This creates a balanced formulation where the protective layer maintains adequate scratch resistance while achieving sufficient flexibility to prevent flex cracking during handling and printing

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 material achieves high water, solvent, and heat resistance while minimizing flex cracking and improving scratch resistance, making it suitable for various applications such as output sheets for facsimile machines and industrial terminals.

Implementation Method 1

particles formed of a hydrophobic polymer (1) and a hydrophilic polymer (2)

Methodology Applied
Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 2

a non-crosslinking urea compound (b) which is at least one compound selected from the group consisting of urea, monoalkylureas, dialkylureas, hydroxyalkylureas, and biuret

Methodology Applied
Scientific EffectHydrogen bonding: Chemical Bonding

Data Source

PatentEP2210744B1Thermosensitive recording material
Publication Date: 2016.08.24 MITSUI CHEMICALS INC

AI summary

The present invention provides a material that is less likely to cause flex cracking, has high scratch resistance, and is suitable for a protective layer for a thermosensitive material. A thermosensitive recording material according to the present invention includes a base, a thermosensitive recording layer formed on the base, and a protective layer formed on the thermosensitive recording layer, wherein the protective layer is formed from a mixture that contains an emulsion (a) containing particles formed of a hydrophobic polymer (1) and a hydrophilic polymer (2) ;and a non-crosslinking urea compound (b). Preferably, the hydrophobic polymer (1) contains an acrylonitrile-derived constitutional unit. Preferably, the non-crosslinking urea compound (b) is urea or a urea derivative.