Water-Soluble Unit Dose Manufacturing Without Cavity Moulding
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Solution Overview
Problem
Current methods for producing water-soluble unit dose detergent articles require a cavity moulding process, which is complex and inefficient, leading to issues like sheet sticking, misalignment, and shrinkage, especially under varying climatic conditions.
Innovation Solution
A process using a water-soluble non-woven fibrous sheet that is unwound, shaped into a tube, sealed, filled with detergent, and sealed again to form a unit dose article without the need for cavity moulding, allowing for efficient production across a range of temperatures and humidities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cavity mould process is used to make water-soluble unit dose articles, then the articles can be formed with proper shape and structure, but the process becomes complex and inefficient with issues like sheet sticking, misalignment, and shrinkage
Solution Approach 1:
The patent removes the cavity mould from the manufacturing process entirely. Instead of forming the unit dose article within a mould cavity, the process uses a flat water-soluble sheet that is sealed at edges to create containment, eliminating the complex cavity moulding step while still achieving proper article formation
Solution Approach 2:
Rather than forming the container shape first using a cavity mould and then filling it, the invention inverts the approach by sealing the sheet edges first to create a flat-contained structure and then filling it with detergent composition, achieving the same functional result with simpler equipment
2Productivity
If a cavity mould process is used, then unit dose articles can be produced, but production efficiency decreases and resource waste increases
Solution Approach 1:
The patent employs continuous sealing operations where the water-soluble sheet moves through sealing units that continuously seal the edges and close the container. This continuous process eliminates the stop-start nature of cavity moulding, improving production efficiency and reducing material waste through optimized material usage
Solution Approach 2:
The invention uses a simple, disposable water-soluble sheet as the container material that is sealed and filled in a straightforward sequence. This approach replaces expensive, complex cavity moulds with simpler sealing mechanisms, reducing both equipment cost and material waste through more efficient material utilization
3Reliability
If conventional water-soluble sheets are used in cavity moulding, then articles can be formed, but sheet sticking, misalignment, and shrinkage occur especially under varying climatic conditions
Solution Approach 1:
The patent specifies particular parameters for the water-soluble sheet including basis weight range (15-60 gsm), fibre length distribution, and composition (polyvinyl alcohol with gel-breaker). These parameter specifications ensure the sheet maintains proper dimensions and does not stick or shrink excessively under varying climatic conditions during the continuous sealing process
Solution Approach 2:
The process includes preliminary conditioning of the water-soluble sheet before sealing, ensuring the sheet is at appropriate moisture content and temperature. This preliminary preparation prevents misalignment and sticking during the sealing operation, especially under varying environmental conditions, by pre-adjusting the sheet properties to optimal ranges
Data Source
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AI summary
A process of making a water-soluble unit dose article (12) in which the process does not include a thermoforming step.