Thermal Transfer Sheet Boiling Resistance via Phenolic Resin
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Solution Overview
Problem
Thermal transfer sheets used in thermofusible transfer systems lack sufficient boiling resistance, which is essential for printed matter to remain intact during sterilization processes or when exposed to boiling hot water, especially on packaging materials like plastic films.
Innovation Solution
A thermal transfer sheet design featuring a substrate with a transferable protective layer containing a cyclic olefin-based polymer and an incompatible resin, and a transferable color layer with a phenolic resin having a softening point of 100° C or more, providing excellent heat and water resistance, and optionally including an inorganic filler for enhanced blocking resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermofusible ink layers are used with standard binder resins, then printability is achieved, but boiling resistance is insufficient
Solution Approach 1:
The patent changes the thermal parameters of the binder resin by selecting a phenolic resin with a softening point of 100°C or higher. This parameter change enables the ink layer to maintain its structural integrity at boiling temperatures while still allowing for effective thermal transfer printing at lower temperatures, thus simultaneously achieving both boiling resistance and printability.
Solution Approach 2:
The patent employs a composite binder resin system combining phenolic resin with specific softening characteristics. This composite material approach allows the ink layer to exhibit dual behavior: remaining stable and resistant to boiling water while maintaining adequate softness and adhesion properties for successful thermal transfer printing.
2Reliability
If high softening point phenolic resin is used in the transferable color layer, then boiling resistance is improved, but printability may be affected
Solution Approach 1:
The patent optimizes the softening point parameter of the phenolic resin to be 100°C or higher, which is the critical threshold for achieving boiling resistance. This precise parameter selection ensures the resin maintains its melting stability during boiling while still allowing thermal transfer at printing temperatures, thereby resolving the contradiction between boiling resistance and printability.
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 thermal transfer sheet achieves satisfactory printability and superior boiling resistance, ensuring the printed matter remains intact and resistant to abrasion, even when subjected to boiling conditions.
Implementation Method 1
the transferable color layer contains a colorant and a phenolic resin having a softening point of 100° C. or more
Implementation Method 2
the transferable protective layer contains a cyclic olefin-based polymer having a glass transition temperature of 100° C. or more as a main component
Implementation Method 3
the transferable protective layer contains a cyclic olefin-based polymer having a glass transition temperature of 100° C. or more as a main component and an incompatible resin with the cyclic olefin-based polymer
Implementation Method 4
the transferable color layer contains a colorant, and a binder resin containing a reaction product between a phenolic resin having a softening point of 100° C. or more and an adduct product of an aliphatic polyisocyanate
Data Source
AI summary
Provided is a thermal transfer sheet which has satisfactory printability and provides a printed matter having excellent boiling resistance.Disclosed is a thermal transfer sheet which is provided with a substrate, at least a transferable protective layer and a transferable color layer in this order on one side of the substrate, and is provided with a back face layer on the other side of the substrate, characterized in that the transferable protective layer contains a cyclic olefin-based polymer having a glass transition temperature of 100° C. or more as a main component and further contains an incompatible resin with the cyclic olefin-based polymer, and the transferable color layer contains a colorant and a phenolic resin having a softening point of 100° C. or more.