Three-Compartment Unit Dose Capsule Sealing for Fast Dissolution
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Solution Overview
Problem
Existing multi-compartment water-soluble detergent capsules face issues such as drooping, complex manufacturing processes, leakage, incomplete dissolution, and improper handling due to floppy seals and thick film skirts, leading to poor cleaning efficiency and consumer inconvenience.
Innovation Solution
A method of producing a unit dose capsule with three compartments, using two sheets of water-soluble polyvinyl alcohol film, where the inter-compartment sealing webs have an average width of 0.3 to 3 mm, forming a sealing web with a peripheral skirt, ensuring rapid dissolution and separation of contents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multi-compartment capsules use flat sealing webs to separate compartments, then manufacturing is simplified, but the capsule becomes floppy and folds along the seal causing handling problems
Solution Approach 1:
The patent applies curvature to the sealing web by forming it into an arch shape rather than keeping it flat. This curved configuration prevents the sealing web from folding along the seal line while maintaining structural integrity and ease of manufacture.
2Ease of operation
If multi-compartment capsules use stacked capsule configuration to prevent seal folding, then handling is improved, but manufacturing becomes complex and requires triple layer seals
Solution Approach 1:
The patent segments the sealing web into a peripheral skirt portion and an arch portion, allowing each segment to serve its specific function while maintaining overall structural simplicity and manufacturing ease.
Solution Approach 2:
By curving the sealing web into an arch shape rather than stacking capsules, the patent achieves stable handling without the complexity of triple-layer seals and stacked configurations.
3Device complexity
If thin film is used to avoid dissolution problems in triple layer seals, then manufacturing complexity is reduced, but leakage occurs due to pin-holing
Solution Approach 1:
The arched configuration of the sealing web distributes mechanical stresses evenly across the film structure, preventing pin-holing and leakage while maintaining film integrity without requiring excessive thickness.
Solution Approach 2:
By dividing the sealing web into functional segments (peripheral skirt and arch portion), the patent optimizes film thickness distribution to prevent leakage while avoiding the dissolution problems of triple-layer seals.
4Stability of the object's composition
If peripheral skirt is made wide and thick for structural support, then capsule stability is improved, but dissolution becomes incomplete and leaves residue
Solution Approach 1:
The arched configuration of the sealing web provides structural support and stability while maintaining thin film thickness, enabling complete dissolution without residue formation.
Solution Approach 2:
By changing the geometric parameters of the sealing web from flat and wide to arched and optimized thickness, the patent achieves both structural stability and complete dissolution without harmful residue.
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 provides stable, leak-resistant capsules with rapid dissolution and dispersion of contents, enhancing cleaning efficiency and consumer convenience by minimizing deformation and residue, while requiring only two film layers for three compartments.
Implementation Method 1
two sheets of water-soluble polyvinyl alcohol film
Data Source
AI summary
The present invention provides a method of producing a unit dose capsule for treatment of a substrate, the method comprising steps: a. placing a first sheet of water-soluble polyvinyl alcohol film over a mould having sets of cavities, each set comprising three cavities arranged on the sealing plane one after the other in circumferential direction; b. heating and applying vacuum to the film to mould the film into the cavities and hold it in place to form three recesses in the film; a first recess (502), the second recess (503), and a third recess (504), the three recesses being connected to respective side recesses by the film; c. filling three different parts of a substrate treatment composition into the three recesses (502, 503, 504), the three parts together forming a full substrate treatment composition; d. sealing a second sheet of film to the first sheet of film across the formed recesses to form the sealing web comprising a peripheral sealing skirt (108) and inter-compartment sealing webs (1024, 1023, 1034) having average sealing width in the range of 0.3 to 3 mm between compartments and a central sealing web (10234) thereby separating the compartments (102, 103, 104) from one another to produce a three compartment capsule (101); and e. cutting between the capsules so that a series of three compartment capsules (101) are formed, each capsule containing a part of a substrate treatment composition in three compartments (102, 103, 104).