Thermoforming Mold Roughness for Water Soluble Pouch Release
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Solution Overview
Problem
Water soluble pouches used for substrate treatment compositions face challenges in predictable and controllable separation from thermoforming molds due to their soft, flexible, and tacky nature, leading to processing irregularities such as damage and misalignment during high-speed manufacturing.
Innovation Solution
A thermoforming mold with a forming surface featuring spaced apart recesses and a continuous land area with an average roughness of 2.2 μm to 10 μm, combined with a vacuum system, facilitates the thermoforming process to create water soluble pouches that can be easily, predictably, and controllably separated from the mold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If water soluble pouches are made soft, flexible, and elastic for product delivery, then they can effectively dissolve and release treatment compositions, but they become difficult to separate from the thermoforming mold
Solution Approach 1:
The mold surface is given different properties in different areas: the recess areas remain smooth for proper pouch formation and sealing, while the land areas are made rough (Ra 0.5-2.5 μm) to reduce adhesion. This local differentiation allows the pouch to form correctly in recesses while easily releasing from land areas.
Solution Approach 2:
The mold surface roughness is pre-engineered before the thermoforming process to prevent sticking. By having the land areas roughened in advance, the pouch material does not adhere to these areas during forming, eliminating the need for additional release mechanisms or post-processing steps.
2Productivity
If high speed manufacturing processes are used to increase productivity, then production output increases, but precise control of pouch movement becomes difficult leading to processing irregularities
Solution Approach 1:
The rough land areas create predictable friction characteristics that allow pouches to be released at specific locations along the mold. This controlled release pattern enables precise positioning even at high speeds, as pouches detach at predetermined points rather than randomly.
Solution Approach 2:
The consistent roughness profile (Ra 0.5-2.5 μm) on land areas creates repeatable release characteristics. This consistency provides implicit feedback that allows the manufacturing process to maintain precision at high speeds without requiring complex active control systems.
3Strength
If the water soluble pouch material is made tacky to improve sealing, then sealing effectiveness increases, but separation from the thermoforming mold becomes more difficult
Solution Approach 1:
The mold surface is differentiated into smooth recess areas for sealing and rough land areas for release. The rough land areas (Ra 0.5-2.5 μm) reduce contact adhesion, allowing tacky pouch material to seal effectively in recesses while still releasing easily from land areas.
Solution Approach 2:
The roughness of land areas is pre-engineered to create low-adhesion zones before sealing occurs. This preliminary surface preparation ensures that even though the pouch material is tacky for sealing, it will not stick to the rough land areas, enabling easy separation after the sealing process.
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 separation process, reducing the force required and improving control, allowing for higher manufacturing line speeds and reducing pouch damage, thereby ensuring consistent production.
Implementation Method 1
a vacuum source operable on the thermoforming mold to apply vacuum pressure to the water soluble pouch
Implementation Method 2
a heated roller positioned downstream of said vacuum source and configured to apply heat to said water soluble pouch
Data Source
AI summary
An apparatus including a thermoforming mold having a forming surface; a plurality of spaced apart recesses in the forming surface, wherein each recess includes a vacuum orifice and each vacuum orifice is in fluid communication with a vacuum source; a continuous land area (250) surrounding the recesses, wherein portions of the land area between the recesses have an average roughness Ra from 2.2 μm to 10 μm.