Multi-layer substrates comprising sandwich layers and polyethylene
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Solution Overview
Problem
Existing cleaning wipes lack sustainability and effective dosing characteristics, with a need for improved manufacturing processes and materials that reduce the use of synthetic fibers while maintaining efficacy and convenience.
Innovation Solution
A multi-layer substrate comprising a top and bottom pulp fiber layer with a melted thermoplastic material layer in between, where the thermoplastic layer provides a fluid pathway for cleaning compositions and bonds with the pulp fibers without chemical adhesives, using polyethylene with specific tan delta values to ensure effective bonding and fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cleaning wipes are made with synthetic fibers, then durability and structure are improved, but sustainability and biodegradability deteriorate
Solution Approach 1:
The invention uses a composite structure combining thermoplastic material layers with pulp fiber layers. The thermoplastic material (e.g., polyethylene, polypropylene) provides structural integrity, durability, and layer bonding, while the pulp fiber layers provide absorbency and biodegradability. This composite approach allows the wipe to achieve both mechanical strength and environmental sustainability by leveraging the complementary properties of synthetic and natural materials.
2Strength
If chemical adhesives are used to bond layers, then layer bonding strength is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The thermoplastic material layer serves a dual function: it provides structural integrity and simultaneously acts as an adhesive to bond the pulp fiber layers together. When the thermoplastic material is applied in a molten or softened state, it naturally adheres to the pulp fibers, eliminating the need for separate chemical adhesive applications. This self-bonding mechanism simplifies the manufacturing process by reducing the number of steps and materials required.
Solution Approach 2:
The invention exploits the temperature-dependent properties of thermoplastic materials. By heating the thermoplastic material to its melting or softening point during manufacturing, it becomes viscous and adhesive, allowing it to bond effectively with the pulp fiber layers. Upon cooling, the material solidifies and maintains strong bonding. This parameter change (temperature) enables the thermoplastic material to transition between a processable state and a functional bonding state, eliminating the need for additional adhesives.
3Strength
If thermoplastic material is melted to bond layers, then layer adhesion is improved, but fluid pathway creation is enhanced
Solution Approach 1:
The thermoplastic material layer is designed with spatially varying properties: in regions where layer bonding is required, the material is applied in sufficient quantity and at appropriate temperatures to create strong adhesion to the pulp fiber layers. In regions where fluid pathways are needed, the material is either applied more sparsely or processed to create gaps and channels. This local differentiation allows the same material layer to simultaneously provide both bonding and fluid transport functions, resolving the contradiction between adhesion and dosing characteristics.
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 results in a sustainable, cost-effective, and efficient cleaning wipe with improved dosing characteristics, reduced risk of delamination, and enhanced microefficacy in sanitization and disinfection, while maintaining softness and avoiding mechanical abrasion.
Implementation Method 1
a melted thermoplastic material layer between the top and bottom pulp layers
Implementation Method 2
the thermoplastic material has a tan delta value of 0.2 to 0.4 within the temperature range of 100° F. to 350° F.
Data Source
AI summary
Multi-layer substrates comprising a top surface layer of pulp fibers, a bottom surface layer of pulp fibers, and a melted thermoplastic material layer between the pulp fiber layers, where the thermoplastic material comprises polyethylene or has a tan delta value of 0.2 to 0.4 within the temperature range of 100° F. to 350° F. The multi-layer substrate can include a cleaning composition loaded onto the multi-layer substrate, where a fluid pathway through the melted thermoplastic material allows the cleaning composition to travel from the top surface layer to the bottom surface layer. The multi-layer substrate may be void of chemical adhesives, where adhesion between the top surface layer and the thermoplastic layer, and between the bottom surface layer and the thermoplastic layer is instead provided by the thermoplastic material itself, which bonds to groups of fibers in the pulp fibers top and bottom surface layers that are in contact with the thermoplastic material as it melts.