Personal Care Substrate Coating via Elastic Deformation
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Solution Overview
Problem
Existing methods for producing personal care articles with coated substrates fail to achieve a shaped area of personal care composition that facilitates easy handling and selective application, particularly for depilatory compositions, as they often result in substrate deformation or uneven coating.
Innovation Solution
A process involving a substrate with a specific yield point (10 Pa to 2000 Pa) and rigidity (0.60 to 0.25 g/cm) is used, where a personal care composition is applied to a plastic substrate with cavities matching the desired shape, allowing deformation without permanent deformation, and excess composition is removed using a wiping member, ensuring a discrete and uniform coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the substrate is deformed into the cavity to achieve shaped coating area, then the personal care composition can be applied to the desired treatment area, but the substrate may permanently deform and lose handleability
Solution Approach 1:
The substrate is deformed into the cavity before the personal care composition is applied, allowing the composition to be deposited in the desired shaped area. The substrate is then returned to its original flat state before removal from the support member, preventing permanent deformation and maintaining handleability for the end user.
Solution Approach 2:
The substrate transitions from a flat state to a deformed state during the coating process, then returns to its original state. This dynamic deformation allows the substrate to conform to the cavity shape for precise coating area definition while recovering to maintain its structural integrity and handleability.
2Manufacturing precision
If a wiping member is used to remove excess composition, then uniform coating thickness is achieved, but the process complexity increases
Solution Approach 1:
A wiping member is introduced as an intermediary element between the substrate and the coating composition. The wiping member selectively removes excess personal care composition from the substrate surface, ensuring uniform coating thickness in the treated area while not affecting the composition that has penetrated into the cavity.
3Ease of operation
If the substrate is made rigid to maintain shape, then handling is improved, but the substrate cannot deform to conform to the treatment area
Solution Approach 1:
The substrate is deformed into the cavity shape before composition application, allowing it to conform to the treatment area. The substrate is then returned to its original flat state before removal, ensuring it remains rigid and handleable for the end user while having achieved the desired conformability during the coating process.
4Reliability
If depilatory composition is applied thick enough to coat hair, then effective depilatory performance is achieved, but excess composition creates mess and waste
Solution Approach 1:
The coating process segments the personal care composition into two distinct areas: excess composition that is removed by the wiping member and represents waste, and the controlled amount that remains in the cavity-treated area and represents useful composition for depilatory performance. This segmentation ensures adequate thickness for effectiveness while minimizing waste.
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
This process enables the production of personal care articles with a shaped area of composition on the substrate, ensuring effective depilatory performance and user convenience by maintaining substrate handleability and preventing water loss, thus enhancing application efficiency and reducing irritation.
Implementation Method 1
deforming the substrate with the applied personal care composition on its first surface into the cavity such that the resulting stress created due to the deformation of the substrate into cavity is less than the elastic limit of the substrate; wherein the substrate is not permanently deformed
Data Source
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AI summary
A process for coating a personal care composition onto at least one discrete treatment area of a substrate having a first and second surface wherein the personal care composition has a yield point of from 10 Pa to 2000 Pa measured via a stress controlled amplitude sweep at a frequency of 1Hz and a temperature of 25°C comprising applying the personal care composition to a portion of the first surface of the substrate; providing a support member with a support surface wherein the second surface of the substrate contacts the support surface of the support member, the support surface having at least one cavity corresponding to the treatment area; providing a wiping member in contact with the first surface of the substrate; deforming the substrate with the applied personal care composition on its first surface into the cavity such that the resulting stress created due to the deformation of the substrate into cavity is less than the elastic limit of the substrate; providing relative motion between the support member and the wiping member such that excess personal care composition is removed and the substrate is coated with a discrete area of personal care composition substantially corresponding to the cavity; wherein the substrate is not permanently deformed; and removing the substrate from the support member.