Leuco dye pastel marking device
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Solution Overview
Problem
Leuco dye-based markers face issues such as drying out, leaking, and mechanical damage, and water-based activators have limitations in applicability and viscosity, leading to delayed color transformation and inefficiencies in dye activation.
Innovation Solution
A leuco dye pastel marking device using a solvent other than water, with a solid or semi-solid mixture of dimethyl adipate, dibenzylamide sorbitol, ethyl cellulose, and pentaerythritol tetrakis, or 12 hydroxystearic acid, which is resistant to drying and mechanical damage, and can be applied using various substrates treated with an activator to trigger color change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If water-based markers are used for leuco dye application, then the dye can be applied to surfaces, but the markers may leak or dry out over time and become unusable
Solution Approach 1:
The patent changes the fundamental parameter of the solvent from water-based to oil-based (specifically a mixture of dimethyl adipate, dibenzylamide sorbitol, and other esters). This parameter change transforms the marker's chemical composition to eliminate water-related issues like drying out and leaking, while maintaining ease of application through the oil-based medium's properties.
2Productivity
If water-based activators are used for leuco dye transformation, then the dye can be activated, but the lower viscosity or chemical properties limit applicability and cause delayed color transformation
Solution Approach 1:
The patent changes the activator's chemical composition from water-based to oil-based, matching the pastel's solvent system. This parameter change enables the activator to be printed or coated directly onto paper surfaces without dilution issues, achieving immediate color transformation upon contact with the leuco dye and expanding applicability to various printing and coating methods.
3Reliability
If encapsulation is used to protect leuco dye particles or activator, then the dye can be protected during storage, but the capsules may be ruptured by rough handling, ruining the encapsulated dye
Solution Approach 1:
The patent extracts the leuco dye and activator from separate encapsulated forms and instead incorporates the dye directly into an oil-based pastel medium. The activator is applied separately to the paper surface, eliminating the need for protective capsules while ensuring the dye remains stable during storage and handling through the oil-based carrier.
4Reliability
If encapsulation is used for leuco dye storage, then the dye can be protected during manufacture, but the encapsulation process is expensive
Solution Approach 1:
The patent eliminates the encapsulation process entirely by using an oil-based pastel formulation that inherently protects the leuco dye during storage and handling. The dye is mixed with dimethyl adipate and other esters to create a stable, non-aqueous medium that prevents premature activation while being cost-effective to manufacture.
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 prevents drying and mechanical damage, ensures consistent dye delivery, and produces robust, vibrant colors by using a non-water-based solvent and activator, allowing for precise and efficient color transformation on treated surfaces.
Implementation Method 1
the principle of leuco dyes—dyes that can be induced to transition between a first, white or colorless 'leuco' form and a second, colored form
Data Source
AI summary
A leuco dye pastel marking device for use with a substrate treated with an activator of the leuco dye, such that drawing upon the substrate will reveal a color, but drawing on a normal surface will have no visible effect. A solvent such as dimethyl adipate is used to store the leuco dye in a longer-lived, more stable, solid form, and varying hardnesses and consistencies may be achieved by the addition of 12 hydroxystearic acid and ethyl cellulose. The substrate may be treated selectively with the activator such that a texture, image, or hidden message is revealed by the application of the leuco dye pastel to the substrate. One or more substrates and one or more leuco dye pastel marking devices may be presented to a child as a coloring book with pastels that only visibly mark the coloring book and no other surface.