Shielded Direct Thermal Label with UV LED Coating
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Solution Overview
Problem
Direct thermal printing labels tend to fade over time and lack resistance to liquids such as solvents and chemicals, and conventional UV varnish is impractical due to heat activation issues.
Innovation Solution
A direct-thermal material with a cured ultraviolet LED coating that has photoinitiators activated within the 365 nm-450 nm wavelength range, allowing for printing without heat activating the direct thermal coating, and providing protection against solvents and chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional UV varnish is applied to protect direct thermal labels, then chemical resistance and durability are improved, but heat activation causes blackening of the printed areas rendering the UV varnish impractical
Solution Approach 1:
The patent changes the curing parameters of the UV coating by using LED UV technology with specific wavelength ranges (365-405 nm) that provide sufficient energy to cure the coating without generating excessive heat that would activate the direct thermal coating and cause blackening. This parameter optimization allows both protection and printability to coexist.
Solution Approach 2:
The patent replaces conventional wide-spectrum UV curing systems with LED UV curing technology. This substitution provides more controlled and targeted UV energy delivery, enabling curing of the protective coating without the excessive heat generation that plagues conventional UV systems, thus avoiding blackening of direct thermal printed areas.
2Ease of manufacture
If direct thermal printing is used to avoid toner and ink costs, then manufacturing cost is reduced, but printed areas fade over time and lack resistance to liquids
Solution Approach 1:
The patent creates a composite structure by applying a UV-curable protective coating over the direct thermal printed surface. This composite combines the cost-effectiveness of direct thermal printing with the protective benefits of the UV coating, achieving both low manufacturing cost and high print durability against fading and liquid resistance.
Solution Approach 2:
The patent applies the UV protective coating in advance, before the direct thermal printing process. This preliminary action ensures that the protective layer is already in place to safeguard the printed areas from fading and liquid damage, while the LED UV curing process used does not interfere with subsequent printing operations.
3Duration of action of stationary object
If UV coating is applied to protect direct thermal labels, then durability is improved, but the curing process heats the direct thermal material causing blackening
Solution Approach 1:
The patent modifies the UV curing parameters by using LED UV technology with controlled wavelength ranges and exposure times that deliver sufficient curing energy while maintaining temperatures below the activation threshold of direct thermal coatings. This prevents blackening while achieving complete cure of the protective coating for maximum durability.
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 enhances the durability and chemical resistance of direct thermal labels, enabling their use in industries where conventional labels fail, such as in medical laboratories and food packaging, without compromising the printing process.
Implementation Method 1
a cured ultraviolet LED coating on the direct thermal coating, the cured ultraviolet LED coating having photoinitiators with substantial activation at an exposure limited to LED radiation at a 365 nm-450 nm wavelength range
Data Source
AI summary
A roll of direct-thermal material may have a length of direct-thermal material including a facestock. An adhesive layer is on a first side of the facestock. A direct thermal coating is on a second side of the facestock, the direct thermal coating configured to selectively darken by heat activation when direct thermal printed. a cured ultraviolet LED coating is on the direct thermal coating, the cured ultraviolet LED coating having photoinitiators with substantial activation at an exposure limited to LED radiation at a 365 nm-450 nm wavelength range, and configured to allow direct thermal printing of the direct thermal coating therethrough, the cured ultraviolet LED coating curable without heat activating the direct thermal coating. The length of direct-thermal material being rolled on itself.