Flushable Tampon Applicator Using PVOH-PEG Composite
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Solution Overview
Problem
Current tampon applicators are not biodegradable and pose disposal challenges, with attempts at using biodegradable materials being costly and environmentally unsustainable, and previous attempts at flushable applicators have failed due to issues with moisture sensitivity and stability.
Innovation Solution
A thermoplastic composition comprising partially-hydrolyzed polyvinyl alcohol (PVOH), polyethylene glycol (PEG), a plasticizer, and a hydrophobic polymeric component, which is injection-moldable and water-dispersible, allowing for the creation of a flushable tampon applicator that maintains integrity during insertion and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If biodegradable polymers are used in injection molded parts, then environmental sustainability is improved, but manufacturing cost increases and thermal processing difficulty increases
Solution Approach 1:
The patent changes the chemical composition parameters by using a specific blend of HPMC (hydroxyl propyl methyl cellulose) and a proprietary resin that is dispersible in cold water, rather than traditional biodegradable polymers. This composition allows injection molding while maintaining biodegradability, thus resolving the contradiction between environmental sustainability and manufacturing feasibility.
Solution Approach 2:
The patent employs a composite material system consisting of HPMC combined with a proprietary resin. This composite formulation achieves both biodegradability and injection moldability, eliminating the need for separate coating processes and reducing manufacturing costs while maintaining environmental sustainability.
2Ease of operation
If PVOH is used to create flushable applicators, then disposal convenience is improved, but the materials must be solution processed which is slow, costly, and energy-intensive
Solution Approach 1:
The patent changes the processing method from solution processing to injection molding by adjusting the physical and chemical parameters of the material formulation. The HPMC/proprietary resin blend is specifically designed to be processable via injection molding, which is a faster, more cost-effective, and less energy-intensive process compared to solution processing, while maintaining flushability.
3Object-affected harmful factors
If cardboard applicators are used, then biodegradability is improved, but the coefficient of friction increases requiring environmentally friendly coatings that add cost
Solution Approach 1:
The patent changes the material from cardboard to an injection-molded polymer composite that inherently provides low friction properties. The HPMC/proprietary resin formulation can be processed to achieve the desired surface friction characteristics without requiring additional coatings, thus eliminating coating costs while maintaining biodegradability.
4Object-affected harmful factors
If HPMC materials are used for flushable applicators, then water dispersibility is improved, but the applicators become extremely brittle and begin to dissolve during insertion
Solution Approach 1:
The patent uses a composite material system of HPMC combined with a proprietary resin that provides structural support. This composite formulation maintains water dispersibility for flushability while the proprietary resin component prevents brittleness and premature dissolution during insertion, ensuring structural stability.
Solution Approach 2:
The patent adjusts the chemical composition parameters by optimizing the ratio and type of HPMC combined with the proprietary resin. This parameter optimization ensures the material remains sufficiently stable during insertion while maintaining its water dispersible properties for flushability after use.
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 a flushable tampon applicator that is comfortable to insert, maintains structural integrity during use, and can be disposed of without clogging sewer pipes, addressing the environmental and disposal issues of traditional applicators.
Implementation Method 1
a water-dispersible injection-moldable composition including partially-hydrolyzed polyvinyl alcohol (PVOH), polyethylene glycol (PEG), plasticizer, and a hydrophobic polymeric component
Implementation Method 2
a water-dispersible injection-moldable composition including partially-hydrolyzed polyvinyl alcohol (PVOH), polyethylene glycol (PEG), plasticizer, and a hydrophobic polymeric component, wherein the composition has a melt flow index of 5-180
Data Source
AI summary
A flushable tampon applicator product includes an outer tube for housing a tampon; an inner tube, at least a portion of which extends into the outer tube, wherein the outer tube includes an outer, body-contacting surface, wherein the inner tube is moveable relative to the outer tube and configured to expel a tampon from the outer tube, and wherein at least one of the outer tube and the inner tube comprises a thermoplastic composition including partially-hydrolyzed polyvinyl alcohol (PVOH), polyethylene glycol (PEG), a plasticizer, and a hydrophobic polymeric component, wherein at least one of the outer tube and the inner tube is a molded part; and a wrapper material configured for storage under high and low moisture storage conditions, the wrapper material having a water vapor transmission rate of less than 0.05 g/100 in2/day.