Thermal Transfer Sheet Peel Force Control
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Solution Overview
Problem
High-speed and compact thermal transfer printers often cause the protective layer in thermal transfer sheets to peel off prematurely due to increased temperature and contact with printing paper, leading to 'foil fall' issues, as conventional sheets lack sufficient adhesion and releasability.
Innovation Solution
A thermal transfer sheet with a protective layer containing a (meth)acrylic resin and vinyl chloride-vinyl acetate copolymer, having a glass transition temperature of 60°C or lower, and a specific mass ratio, which provides a high peel force in a non-heated state and reduced peel force in a heated state, ensuring reliable adhesion and releasability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protective layer is made with high adhesion to prevent foil fall, then reliability is improved, but releasability during transfer deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature (Tg) of the (meth)acrylic resin to 60°C or lower and adjusting the mass ratio between (meth)acrylic resin and vinyl chloride-vinyl acetate copolymer to 1:4 to 4:1. These parameter adjustments enable the protective layer to achieve both strong adhesion at room temperature and easy releasability during thermal transfer by utilizing temperature-dependent changes in material properties.
Solution Approach 2:
The patent uses composite materials by combining (meth)acrylic resin with vinyl chloride-vinyl acetate copolymer in specific proportions (1:4 to 4:1 mass ratio). This composite formulation leverages the complementary properties of both polymers to achieve optimal balance between adhesion and releasability, where the (meth)acrylic resin provides bonding strength and the vinyl chloride-vinyl acetate copolymer contributes to thermal responsiveness and peelability.
2Productivity
If printing speed is increased to improve productivity, then productivity is improved, but temperature control becomes more difficult leading to premature peeling
Solution Approach 1:
The patent addresses temperature control challenges at high printing speeds by adjusting the glass transition temperature parameter of the (meth)acrylic resin to 60°C or lower. This parameter change ensures that the protective layer remains stable during rapid printing operations while preventing premature peeling caused by residual heat from the thermal head, thereby enabling high-speed printing without compromising layer integrity.
3Volume of moving object
If printer becomes more compact to improve space efficiency, then device size is reduced, but transport paths become denser and more complicated increasing risk of foil fall
Solution Approach 1:
The patent enhances the stability of the protective layer in compact printers by controlling the glass transition temperature of the (meth)acrylic resin to 60°C or lower and optimizing the mass ratio of (meth)acrylic resin to vinyl chloride-vinyl acetate copolymer (1:4 to 4:1). These parameter adjustments ensure that the protective layer maintains strong adhesion and resistance to premature peeling even when subjected to the denser, more complicated transport paths found in compact printer designs.
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
Prevents foil fall and ensures high adhesion between the transfer layer and substrate in non-heated conditions while allowing easy transfer in heated states, even in compact printers with high thermal energy application.
Implementation Method 1
the protective layer contains a (meth)acrylic resin having a glass transition temperature (Tg) of 60°C or lower
Implementation Method 2
the transfer layer has a peel force in a heated state of 10 N/m or less, and the transfer layer is transferred by way of a heating means such as a thermal head or a heating roll
Implementation Method 3
an adhesive layer which forms an adhesive bond with the protective layer and the substrate; the adhesive layer has an adhesive force of 0.03 N/mm or more
Data Source
Figure 1~2
Figure 3
AI summary
[Problem to be solved] An object of the present invention is to provide a thermal transfer sheet in which a transfer layer and a substrate included therein exhibit a high level of adhesion therebetween even when used in a compact printer that causes the thermal transfer sheet to be heated by the heat of a thermal head, and in which the transfer layer exhibits a high level of releasability when being transferred. [Solution] The thermal transfer sheet according to the present invention is characterized by including at least a substrate and a transfer layer: the transfer layer including at least a protective layer provided so as to be peelable from the substrate; the transfer layer having a peel force in a non-heated state of 1 N/m or more; and the transfer layer having a peel force in a heated state of 10 N/m or less.