Breathable Artificial Leather With Microporous Polyurethane Top Layer
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Solution Overview
Problem
Existing methods for producing breathable multi-layer artificial leather struggle to create a porous top layer using polyurethane dispersions, as they tend to form closed films, requiring additional expensive processes like needling that affect the visual appearance.
Innovation Solution
Applying an aqueous aliphatic polyurethane dispersion in liquid form to a substrate and rapidly evaporating the water content at high temperatures to prevent film formation, resulting in a microporous top layer with pore sizes that allow breathability without disturbing the visual impression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane dispersion is applied to substrate and allowed to solidify normally, then a continuous film is formed providing good coverage and abrasion resistance, but the film becomes closed and non-porous preventing breathability
Solution Approach 1:
The patent applies porous materials by controlling the drying process to form micropores within the polyurethane film matrix. The rapid evaporation of water creates a porous structure with pore sizes of 1-10 μm that maintains both breathability and mechanical integrity, eliminating the need for subsequent mechanical pore formation processes.
Solution Approach 2:
The patent changes the drying parameters by rapidly increasing temperature to accelerate water evaporation. By controlling the drying rate and temperature profile, the system transforms the film formation process to create micropores during drying rather than forming a closed film, thereby achieving breathability without compromising abrasion resistance.
2Reliability
If additional processes like needling are applied to create pores in the top layer, then breathability is improved, but the visual appearance is degraded and production cost increases
Solution Approach 1:
The patent applies preliminary action by incorporating pore formation into the initial film drying process rather than applying it later through separate mechanical processes. The micropores are formed during the drying stage itself, eliminating the need for subsequent needling or stretching operations and reducing overall production costs while maintaining visual appearance.
Solution Approach 2:
The patent extracts the pore formation function from separate mechanical processes and integrates it into the drying process. By taking out the needling step entirely and achieving pore formation through controlled evaporation, the method reduces production complexity and cost while preserving the aesthetic quality of the surface.
3Reliability
If water content of polyurethane dispersion is evaporated rapidly by high temperature supply, then micropores are formed providing breathability, but film formation is prevented which may reduce coverage
Solution Approach 1:
The patent applies periodic action through a two-stage drying process: first rapid evaporation to create micropores, then controlled drying to complete film formation. This staged approach ensures that pore formation occurs during the initial rapid drying phase while the subsequent phase allows the film to consolidate and achieve uniform coverage, resolving the contradiction between porosity and film integrity.
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 method produces a breathable artificial leather with small, imperceptible micropores that enhance seating comfort and abrasion resistance, eliminating the need for costly additional processes like needling, while maintaining an aesthetically pleasing appearance.
Implementation Method 1
immediately after the application of the polyurethane dispersion the water content of the same is evaporated by the supply of heat within such a short time that a film-free drying of the polyurethane dispersion is effected on the base to form the top layer with micropores
Data Source
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AI summary
The manufacturing of breathable multilayered artificial leather with a carrier layer (3) from a textile surface structure for motor vehicles as seat cover, comprises applying and hardening a covering layer (1) on a removable base with a thickness of 30-100 mu m in a dry condition of 30-40 g/m 2>, applying an intermediate layer (2) on the covering layer based on a polyurethane, applying the intermediate layer on the carrier layer based on partially opened cell polyurethane-impact foam, and removing the base from the covering layer. The manufacturing of breathable multilayered artificial leather with a carrier layer (3) from a textile surface structure for motor vehicles as seat cover, comprises applying and hardening a covering layer (1) on a removable base with a thickness of 30-100 mu m in a dry condition of 30-40 g/m 2>, applying an intermediate layer (2) on the covering layer based on a polyurethane, applying the intermediate layer on the carrier layer based on partially opened cell polyurethane-impact foam, removing the base from the covering layer, applying and imprinting an aqueous aliphatic polyurethane dispersion in fluid form on the base for the formation of the covering layer with a solid content of 30-60 %, vaporizing the water content of the polyurethane dispersion by supplying heat within a short time and producing a film free drying of the dispersion on the base under the formation of the covering layer with micropores. The micropores are produced with a diameter of 10-70 mu m in the covering layer. The dispersion is sprayed on the base in drop form by an injection nozzle. The application of the dispersion on the base is carried out by a screen- and/or sieve printing process. The base is formed in the form of strip-shaped and continuous circular manner and is led over a heated roller to heat the base on a suitable temperature for the vaporization of the water content of the dispersion. The dispersion applied on the base is heated by heat radiation and/or microwaves for the vaporization of the water content. The heat supply is carried out by the base. The water content of the dispersion applied on the base is vaporized in less than 5 seconds. A siliconized textile surface structure or siliconized paper or a metallic substrate or a fabric coated with polytetrafluoroethylene is used as base of a plastic foil. The base is provided with an upper surface profile. The dispersion contains water-soluble and low-boiling organic solvents. The intermediate layer is applied on the covering layer. The intermediate layer has a foam weight of 400-500 g/l. Two intermediate layers are applied one after the other in a thickness of 200-800 mu m on the covering layer and/or the intermediate layer. The first intermediate layer applied on the covering layer has a foam weight of 400-600 g/l and the second intermediate layer has a foam weight of 300-500 g/l. The intermediate layers are produced with an average pore size of 100-200 mu m. A varnish layer (4) is applied on the covering layer, whose side is turned away to the intermediate layer after the removal of the base. The upper surface of the covering layer is embossed after the removal of the base by vacuum embossing or an edge-shaped embossing profile. A clutch, tissue, fabric, fleece or its combinations is used as the carrier layer with or without impregnation. The carrier layer is applied on not yet completely dried up intermediate layer, so that the carrier layer partially sinks into the intermediate layer. An independent claim is included for breathable multilayered artificial leather with a carrier layer from textile surface structure.