PVOH Film Blend for Fast-Dissolving Residue-Free Unit Dose Articles
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Solution Overview
Problem
Water-soluble unit dose articles using polyvinyl alcohol (PVOH) films face issues with gelling during dissolution, leading to delayed cleaning onset and residue formation, especially in short and cold temperature cleaning processes, which can deposit on fabrics or washing machines.
Innovation Solution
A water-soluble film comprising a blend of PVOH homopolymer and PVOH copolymer with specific viscosity and hydrolysis ranges, along with anionic monomer units, to enhance dissolution speed and minimize residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a PVOH film is used to provide sufficient strength during storage and transport, then the film does not rip or tear, but it may not dissolve adequately during the wash cycle, leading to residues
Solution Approach 1:
The patent uses a composite material system consisting of PVOH polymer blended with specific surfactants and optional additives. This composite formulation allows the film to maintain mechanical strength for storage and transport while enabling rapid dissolution during the wash cycle by reducing intermolecular forces through surfactant action.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the PVOH film by controlling the degree of hydrolysis (60-80%), viscosity (5-15 cP), and molecular weight. These parameter changes optimize the balance between film strength for handling and dissolution rate for washing performance.
2Productivity
If the detergent interacts with PVOH during initial dissolution, then cleaning action begins, but gelling occurs that slows down further dissolution, delaying cleaning onset and leaving residues
Solution Approach 1:
The patent introduces surfactants as intermediary substances that mediate between the PVOH polymer and water. The surfactants prevent direct gel-forming interactions between detergent and PVOH by adsorbing at polymer interfaces, thereby maintaining solution homogeneity and preventing gelling while still allowing cleaning action to proceed.
Solution Approach 2:
The patent converts the potentially harmful gelling effect into a benefit by using controlled gelation inhibitors and surfactants that prevent excessive gel formation. The same interactive mechanisms that could cause gelling are harnessed to control dissolution rate and improve cleaning efficiency through optimized surfactant-polymer interactions.
3Ease of operation
If residues are formed on fabrics or washing machine, then they can be redissolved, but this requires a further step from the user
Solution Approach 1:
The patent applies preliminary anti-action by incorporating dissolution enhancers and surfactants that prevent residue formation in the first place. These additives work during the initial dissolution phase to ensure complete polymer breakdown and prevent residue deposition on fabrics or washing machine surfaces, eliminating the need for additional user steps.
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 film blend ensures rapid dissolution, reduces residue formation, and maintains structural integrity, improving cleaning efficiency and minimizing unwanted residues on fabrics or washing machines.
Implementation Method 1
When the water-soluble unit dose article is added to water, the film dissolves/disintegrates releasing the internal contents into the surrounding water to create a wash liquor
Data Source
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AI summary
Water-soluble films, water-soluble unit dose articles, and methods of their manufacture and use. The film includes a polyvinyl alcohol resin blend comprising a PVOH homopolymer consisting essentially of vinyl alcohol monomer units and vinyl acetate monomer units and a PVOH copolymer comprising anionic monomer units, vinyl alcohol monomer units and vinyl acetate monomer units.