Siloxane-Modified Urethane Resin Back-Surface Layer for Heat Resistance
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Solution Overview
Problem
Conventional resin compositions for back-surface layers in heat-sensitive transfer recording materials face challenges in achieving high heat resistance, durability, and low migration of silicone, especially when the temperature of thermal heads is increased.
Innovation Solution
A resin composition for a back-surface layer is developed, comprising a siloxane-modified urethane- or urea-based resin A, a resin B with an active-hydrogen-containing group and a glass transition point lower than 100°C, and a cross-linking agent C, which together form a strong film that prevents silicone bleeding and migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature of thermal head is increased to improve heat-sensitive transfer recording, then printing performance is improved, but heat resistance and sticking prevention ability of back-surface layer deteriorates
Solution Approach 1:
The back-surface layer uses a composite resin composition containing siloxane-modified polyurethane resin (5-55 mass%), polyol resin (15-80 mass%), and isocyanate crosslinking agent (5-40 mass%). This composite structure combines the heat-resistant properties of siloxane-modified polyurethane with the low glass transition temperature and flexibility of polyol resin, while the isocyanate crosslinking agent creates a crosslinked network that prevents sticking and enhances durability at high temperatures.
Solution Approach 2:
The invention controls the glass transition temperature of the back-surface layer to be below 100°C by carefully selecting and proportioning the polyol resin content. This parameter optimization ensures the layer remains flexible and non-sticking at elevated thermal head temperatures while maintaining adequate heat resistance through the crosslinked structure.
2Reliability
If silicone content is increased to improve heat-resistant sliding properties, then heat resistance is improved, but silicone migration and bleeding worsens
Solution Approach 1:
The invention uses siloxane-modified polyurethane resin where the silicone is chemically bonded to the polyurethane backbone rather than being physically mixed. This composite structure anchors the silicone groups within the polymer matrix, preventing migration and bleeding while maintaining the heat-resistant sliding properties that silicone provides.
Solution Approach 2:
The polyol resin acts as an intermediary matrix that hosts the siloxane-modified polyurethane resin. This intermediate structure provides a compatible environment that stabilizes the silicone groups and prevents their migration, while still allowing the silicone to exert its heat-resistant sliding effect on the thermal head.
3Reliability
If high glass transition temperature resin is used to improve heat resistance, then heat resistance is improved, but durability and flexibility deteriorates
Solution Approach 1:
The invention optimizes the glass transition temperature parameter to be below 100°C by controlling the polyol resin content and molecular structure. This parameter setting balances heat resistance with flexibility and durability, ensuring the back-surface layer can withstand repeated thermal cycling and mechanical stress without cracking or deteriorating.
Solution Approach 2:
The invention creates local quality differentiation within the back-surface layer through the crosslinked structure. The isocyanate crosslinking agent creates localized crosslinked networks that provide heat resistance and structural integrity, while the uncrosslinked polyol resin matrix maintains flexibility and durability throughout the material.
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 proposed resin composition achieves a back-surface layer with enhanced heat resistance, durability, and adhesiveness, while preventing silicone migration and contamination of the thermal head, thus supporting increased thermal head temperatures and improving printed image quality.
Implementation Method 1
a cross-linking agent C, wherein a cross-linked structure is formed by a reaction between the resin B and the cross-linking agent C
Implementation Method 2
the resin composition for a back-surface layer... formation of a back-surface layer
Data Source
AI summary
There are provided a useful resin composition for a back-surface layer and a heat-sensitive transfer recording material using the same, wherein under the circumstances where the temperature of thermal heads has been increased, the back-surface layer of the formed heat-sensitive transfer recording material has more excellent heat resistance, damage to a thermal head can be alleviated, and durability is excellent in that bleeding is suppressed even if the silicone content is increased. The present invention provides a resin composition for a back-surface layer to be used for forming a back-surface layer of a heat-sensitive transfer recording material, the resin composition containing, as film-forming components, a siloxane-modified urethane- or urea-based resin A, a resin B, and a cross-linking agent C, wherein the resin A contains a polysiloxane component in a range of 5 to 55%, the resin B has at least one active-hydrogen-containing group and has a glass transition point of lower than 100°C, and when the total amount of the resin A, resin B, and the cross-linking agent C is assumed to be 100%, the resin A is contained within a range of 1 to 79%, the resin B is contained within a range of 1 to 79%, and the cross-linking agent C is contained within a range of 20 to 80%. The present invention also provides a heat-sensitive transfer recording material using the resin composition for a back-surface layer.