Reversibly Bonded Foam Products Using Roller-Applicable Dispersion Adhesive
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Solution Overview
Problem
Current adhesive technologies for bonding foams, such as polychloroprene-based and polyurethane-based dispersion adhesives, face challenges including environmental concerns, difficulty in precise application, and hindrance to recycling and upcycling due to residual adhesive effects, especially when dealing with mixed foam materials in furniture and mattresses.
Innovation Solution
A method using a one-component dispersion adhesive based on aqueous polyurethane or acrylate dispersions with a plasticizer, applied by roller to specific areas, allowing for cohesive fracture separation and enabling precise bonding and easy recycling of substrates without the need for a coagulating component, ensuring initial adhesion and separability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polychloroprene-based dispersion adhesives are used for bonding foams, then sufficient initial tack and processing capability are achieved, but environmental pollution from solvent emissions and interference with recycling processes occur
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive by using polyurethane or polyurethane-urea dispersions instead of polychloroprene dispersions. This substitution maintains the necessary adhesive properties (initial tack, bonding strength) while eliminating the harmful effects (VOC emissions, recycling interference) associated with polychloroprene-based adhesives.
2Area of stationary object
If spray application method is used for adhesive application, then bonding coverage is achieved, but overspray loss and imprecise application occur
Solution Approach 1:
The invention replaces the spray application method (aerosol delivery system) with a roller application system. This mechanical substitution allows for direct, controlled application of the adhesive to the substrate surface, eliminating overspray loss while ensuring precise and uniform coverage through the roller's contact with the substrate.
3Reliability
If two-component spray coagulation method is used, then adhesive bonding is achieved, but process complexity and error proneness increase
Solution Approach 1:
The invention merges the two separate components (adhesive and coagulant) into a single integrated adhesive formulation. The polyurethane or polyurethane-urea dispersion itself provides both the adhesive properties and the bonding mechanism, eliminating the need for a separate coagulant component and simplifying the application process to a single-step operation.
4Strength
If adhesive residues are present on foam substrates, then bonding function is achieved, but interference with foam recycling and upcycling occurs
Solution Approach 1:
The invention changes the chemical nature of the adhesive residues by using polyurethane or polyurethane-urea dispersions instead of polychloroprene dispersions. The polyurethane-based residues are compatible with foam recycling processes and can be reprocessed together with the foam material, whereas polychloroprene residues interfere with the recycling and upcycling of foam substrates.
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
This approach simplifies the bonding process, enhances initial adhesion, allows for precise application, and facilitates easy separation and recycling of substrates, reducing environmental impact and improving the recycling efficiency of foam composites.
Implementation Method 1
the targeted use of a plasticizer in a dispersion adhesive to adjust the initial adhesion when bonding substrates
Implementation Method 2
the composite can be separated again after complete drying by forming a cohesive failure in the adhesive
Implementation Method 3
Applying a dispersion adhesive to a bonding area... based on aqueous polyurethane or acrylate dispersions
Data Source
Figure 1a~1d
Figure 2~3c
AI summary
A method for bonding substrates, in particular foams, comprises the steps of: a) applying a dispersion adhesive (DK) to a bonding area of a first substrate (S1) by roller application; b) contacting the bonding area of the first substrate (S1) with a second substrate (S2) to be bonded; c) pressing the two substrates (S1, S2) together so that a bonded composite (V') of the first and second substrate is obtained, in particular such that the bonded composite (V') is separable by forming a cohesive failure in the adhesive; wherein the dispersion adhesive (DK) comprises an aqueous polyurethane and/or an aqueous acrylate dispersion as well as a plasticizer.