Embossable PU Foam Layered Material for Precise Surface Structuring
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Solution Overview
Problem
Existing methods for producing surface-structured layer materials face challenges such as energy inefficiency, difficulty in controlling capillary formation, and limitations in surface design flexibility, particularly in the processing industry, where precise and cost-effective creation of individual surfaces with technical functions is required.
Innovation Solution
A method involving a layer material composed of a single layer of aqueous PU dispersions with a special type of PU foam that can be thermoplastically deformed under heat and pressure, allowing for precise surface structuring and embossing without voids or cracks, even after long-term storage, using embossing parameters and pressure-elastic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum embossing is used to structure the top layer, then surface structure is achieved, but only the top layer is structured and the intermediate layer remains unstructured
Solution Approach 1:
The embossing process is divided into two distinct stages: first embossing the intermediate layer to create capillary structures, then embossing the top layer to create surface patterns. This segmentation allows each layer to be structured independently with appropriate parameters, resolving the contradiction between achieving precise surface structure and enabling versatile layer structuring.
Solution Approach 2:
The intermediate layer is embossed in advance to create capillary channels before the top layer is applied and embossed. This preliminary action ensures that the intermediate layer has the required structural functionality before the final surface structuring, enabling both precise surface structure and versatile layer functionality.
2Manufacturing precision
If embossing pressure of less than 125 kg/cm3 is used to structure a foamed layer, then the foamed layer is structured, but the above layer is applied after embossing requiring additional processing steps
Solution Approach 1:
The foamed intermediate layer is embossed with capillary structures before the top layer is applied. This preliminary structuring of the intermediate layer allows subsequent top layer embossing to be performed at lower pressures, improving both structuring precision and production efficiency by enabling multi-layer embossing in sequence rather than requiring high-pressure simultaneous embossing.
Solution Approach 2:
The embossing process is segmented into intermediate layer embossing followed by top layer embossing. This segmentation allows each layer to be structured with optimized pressure parameters, improving overall production efficiency and precision while avoiding the need for high-pressure simultaneous multi-layer embossing.
3Manufacturing precision
If PU dispersion is dried and solidified using heat to structure the top layer, then the coating is structured, but a lot of energy is consumed and emissions increase
Solution Approach 1:
The intermediate layer is embossed in advance to create capillary structures that facilitate moisture removal. This preliminary action allows the top layer to be dried at lower temperatures and for shorter times, reducing energy consumption and emissions while maintaining structuring precision.
Solution Approach 2:
The embossed intermediate layer creates a porous structure with capillary channels that enhance moisture transport. This porous structure allows more efficient drying of the top layer at reduced temperatures, lowering energy consumption and emissions while achieving the required structuring precision.
4Manufacturing precision
If thick dispersion mixtures are dried, then the coating is solidified, but drying is complicated and requires increasing temperature consuming more energy
Solution Approach 1:
The embossed intermediate layer provides a porous structure with capillary channels that facilitate efficient moisture removal from thick dispersion mixtures. This allows complete drying at lower temperatures without requiring progressively increasing temperature cycles, reducing energy consumption while maintaining solidification quality.
Solution Approach 2:
The embossed intermediate layer acts as an intermediary that facilitates moisture transport away from the top layer during drying. This mediator function enables efficient drying of thick dispersions at reduced temperatures, lowering energy consumption while achieving complete solidification.
5Manufacturing precision
If capillaries are formed in thin coatings, then capillary structures are created, but their number and diameter are difficult to control and they must communicate with holes in the adhesive layer
Solution Approach 1:
The capillary structure formation is segmented into two independent processes: first embossing the intermediate layer to create controlled capillary channels, then applying the top layer. This segmentation allows precise control of capillary number and diameter in the intermediate layer without being constrained by adhesive layer hole patterns, reducing device complexity.
Solution Approach 2:
The capillary structures are formed in the intermediate layer before the top layer is applied. This preliminary action allows independent optimization and precise control of capillary dimensions without being constrained by subsequent top layer requirements or adhesive layer hole patterns, simplifying the overall process.
6Stability of the object's composition
If the coating is cross-linked, then the coating is stabilized, but it cannot be restructured and capillaries would close under high pressure
Solution Approach 1:
The coating system is segmented into two layers with different functional properties: the intermediate layer is embossed to create stable capillary structures, while the top layer remains thermoplastic and restructureable. This segmentation allows the stabilized intermediate layer to maintain capillary integrity while the top layer can be restructured if needed, resolving the contradiction between stability and adaptability.
Solution Approach 2:
The intermediate layer is embossed and stabilized in advance to create permanent capillary structures. This preliminary stabilization ensures capillary integrity while the top layer remains flexible and restructureable, allowing the system to achieve both stability and versatility.
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
Enables the creation of surface-structured materials that are easy to produce, store, and process, with improved mechanical and physical properties, allowing for cost-effective and energy-efficient production of format blanks and stamped parts with complex structures, such as those for shoes, while minimizing waste and environmental impact.
Implementation Method 1
The embossed intermediate layer is permeable to moisture, so that moisture can be removed over and/or through the surface of the coating
Implementation Method 2
a layer 2 made of PU foam, which is thermoplastic and can therefore be independently structured even after a longer period of storage
Implementation Method 3
All that is necessary is to thermally activate the surface-structurable layer and to deform it thermoplastically above its softening point using a die under heat and pressure
Implementation Method 4
deform it thermoplastically above its softening point using a die under heat and pressure
Implementation Method 5
The embossed intermediate layer is permeable to moisture, so that moisture can be removed over and/or through the surface of the coating
Data Source
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AI summary
The invention relates to a method for producing a surface-structured layered material which has a backing layer (1) and a polyurethane layer (2) connected thereto, the backing layer (1) used, in particular in pieces, being a leather, preferably a smoothed full-grain leather or a split cowskin, a textile material, preferably a woven fabric or a knitted fabric, a cellulose fibre material, a split foam, a leather fibre material or a microfibre fleece and being connected to the layer (2), and the layer (2) applied to the backing layer (1) being at least one, preferably a single layer formed of a PU foam, in particular containing gas pockets, preferably a whipped PU foam optionally containing hollow microspheres and/or a PU foam containing hollow microspheres. According to the invention: - the PU foam, in particular containing gas pockets, is created with a PU dispersion mixture, wherein the individual PU dispersions used to create the PU dispersion mixture exhibit different softening points in the dry state; - to create the PU dispersion mixture, one or more PU dispersions having heat-activatable melting and contact adhesive properties and a softening point in the dry state greater than 40°C, preferably greater than 45°C, in an amount of 18 to 52 wt% of the finished PU dispersion mixture is/are mixed with one or more PU dispersions without melting and contact adhesive properties and with a softening point greater than 95°C, preferably greater than 125°C, in an amount of 39 to 73 wt% of the finished PU dispersion mixture; - the PU dispersion mixture for the layer (2) is applied to the backing layer (1) with a thickness such that the layer has a thickness in the dried state of 0.075 to 0.450 mm, preferably 0.150 to 0.280 mm; - before or during structuring of the PU foam, a further layer (3) of a non-foamed PU dispersion which is a mixture of multiple PU dispersions is applied to the layer (2); - the backing layer (1) is optionally cut or punched into blanks or pattern parts before or after the application of the PU foam, in particular after the drying thereof, and the coated blanks or pattern parts are subjected to stamping or structuring under pressure and temperature; and - the backing layer (1), the further layer (3) and the layer (2) are compressed and joined to one another and structured with a die (4) under application of a contact pressure of 4 to 48 kg/cm2, preferably 4 to 48 kg/cm², in particular 18 to 25 kg/cm².