Antimicrobial hydrophilic polyurethane foam sponges
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Solution Overview
Problem
Hydrophilic polyurethane sponges tend to shrink and become stiff in their dry state, leading to consumer preference for moist packaging, which can result in bacterial, fungal, and mold growth due to the inability of antimicrobial treatments used on cellulosic sponges to work effectively on these materials.
Innovation Solution
Incorporating an antimicrobial composition with an acetate salt solution humectant or a non-halogen humectant salt solution having a pH between 3 and 10 and a water activity of less than 0.9 at 25°C into hydrophilic polyurethane foam sponges to partially or completely kill microorganisms such as bacteria, fungi, molds, and viruses, while maintaining the sponge's loft and softness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If sponges are packaged in a moist condition to maintain loft and softness, then consumer preference is satisfied, but microbial growth (bacteria, fungus, mold) occurs
Solution Approach 1:
The patent changes the chemical parameters of the packaging environment by using an antimicrobial composition with controlled pH (between 2 and 12) and water activity (less than 0.95). This creates a moist environment that maintains sponge loft and softness while the specific parameter ranges prevent microbial growth, resolving the contradiction between consumer preference and microbial safety.
Solution Approach 2:
The antimicrobial composition acts as an intermediary substance between the sponge and the external environment. It provides the necessary moisture to maintain sponge properties while simultaneously preventing microbial contamination, serving as a protective mediator that satisfies both requirements.
2Object-affected harmful factors
If conventional antimicrobial treatments are applied to hydrophilic polyurethane sponges, then microbial growth is reduced, but the treatments are ineffective due to material incompatibility
Solution Approach 1:
The patent identifies that conventional antimicrobial treatments fail on hydrophilic polyurethane sponges and develops a new treatment with specific parameter ranges: pH between 2 and 12 and water activity less than 0.95. These parameter changes make the treatment effective for this specific material type, resolving the reliability issue.
Solution Approach 2:
The patent adapts the antimicrobial treatment concept from cellulosic sponges but modifies it specifically for hydrophilic polyurethane sponges. By copying the general approach and adjusting the parameters to match the different material properties, the treatment becomes effective where conventional methods fail.
3Object-affected harmful factors
If sponges are packaged dry to prevent microbial growth, then safety is improved, but sponges shrink and become excessively stiff
Solution Approach 1:
The patent changes the packaging approach from dry to controlled-moisture conditions. By maintaining specific parameter ranges (pH 2-12, water activity <0.95), the sponge remains in a damp state that preserves its loft and softness while the antimicrobial properties prevent microbial growth, resolving the contradiction between safety and shape maintenance.
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 antimicrobial composition effectively kills microorganisms within the sponges, preventing growth and maintaining the sponge's desired properties, as demonstrated by passing ASTM G21 and aging tests, ensuring safety and consumer preference.
Implementation Method 1
incorporating an antimicrobial composition including a non-halogen containing humectant comprising a salt solution having a pH between about 3 and 10 and a water activity of less than 0.9 at 25° C.
Implementation Method 2
absorbing into the hydrophilic polyurethane foam sponge an input solution comprising an acetate salt solution humectant
Data Source
AI summary
The inventors of the present disclosure recognized that, surprisingly, the antimicrobial treatments used on cellulosic sponges do not work in hydrophilic polyurethane sponges. As such, the inventors of the present disclosure discovered a need for an antimicrobial treatment for use on hydrophilic polyurethane foam sponges. The present inventors invented one antimicrobial composition for use on hydrophilic polyurethane foam sponges including an acetate salt solution humectant. The present inventors invented another antimicrobial composition for use on hydrophilic polyurethane foam sponges including a non-halogen humectant comprising a salt solution having a pH between about 3 and 10 and a water activity of less than 0.9 at 25° C.