Solvent-Free Artificial Leather Coating for Flexing Endurance
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Solution Overview
Problem
Existing processes for producing artificial leather, such as the dry and wet processes, consume significant amounts of solvents, harming the environment, and the surface properties of artificial leather, like gloss and color, need improvement, especially for applications like footwear where mechanical and visual properties must meet high standards.
Innovation Solution
A solvent-free process involving a release layer, application of a top coat and polyurethane system components comprising an isocyanate and polyol, with a specific isocyanate index, followed by curing and optional additional polyurethane and substrate layers, to produce artificial leather with improved mechanical and visual properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solvent-free polyurethane system components are used, then environmental friendliness and mechanical properties are improved, but adherence between top coat and polyurethane layer is insufficient
Solution Approach 1:
The invention changes the isocyanate index parameter to a specific range (101-140) to optimize both environmental friendliness and adherence. This parameter adjustment ensures proper crosslinking density and chemical reactivity, creating sufficient adhesion between the top coat and polyurethane layer while maintaining solvent-free eco-friendly production
Solution Approach 2:
The invention uses a composite polyurethane system combining isocyanate component (A) and polyol component (B) with specific molecular structures and functionalities. This composite approach creates a multi-phase structure that enhances interfacial adhesion between top coat and polyurethane while maintaining environmental compatibility through solvent-free formulation
2Ease of manufacture
If conventional dry or wet processes are used, then production is simpler, but solvent consumption is high and environment is damaged
Solution Approach 1:
The invention changes the fundamental parameter of solvent content from conventional levels to zero (solvent-free), eliminating environmental harm while maintaining production simplicity through direct application of polyurethane system components that cure in situ without requiring solvent evaporation or coagulation baths
Solution Approach 2:
The invention converts the potential disadvantage of solvent-free formulation (which can lead to poor wetting and adhesion) into a benefit by using the isocyanate index control to create optimal crosslinking that enhances both environmental friendliness and mechanical performance, turning an ecological constraint into a performance advantage
3Illumination intensity
If top coat is applied to improve surface properties, then gloss and color are improved, but mechanical properties and adherence may be compromised
Solution Approach 1:
The invention changes the isocyanate index parameter to optimize the interface between top coat and polyurethane layer, ensuring that the top coat achieves desired gloss and color while the controlled crosslinking density maintains mechanical integrity and flexing endurance of the overall artificial leather structure
Solution Approach 2:
The invention creates a composite structure where the top coat and polyurethane layer form a unified multi-phase material system. The specific isocyanate index ensures compatible molecular structures and interfacial chemistry, allowing the top coat to provide surface aesthetics while the polyurethane base maintains mechanical strength through optimized crosslinking
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 process results in artificial leather with excellent mechanical properties, including flexing endurance, and a strong bond between the top coat and polyurethane layer, while being environmentally friendly, suitable for high-demand applications like footwear.
Implementation Method 1
applying first polyurethane system components comprising an isocyanate component (A) and a polyol component (B) to the top coat to form a first polyurethane layer... curing the polyurethane system components to form a polyurethane layer
Data Source
AI summary
The present invention relates to a process for production of artificial leather comprising top coat, polyurethane layer and optional substrate layer, said process comprising i) providing a release layer, ii) applying one or more than one layer of a top coat to the release layer to an overall top coat layer thickness in the range from 1 to 500 μm, iii) applying first polyurethane system components comprising an isocyanate component (A) and a polyol component (B) to the top coat to form a first polyurethane layer, wherein the isocyanate index of the first polyurethane system components is in the range from 101 to 140, iv) optionally applying further polyurethane system components to the first polyurethane layer to form further polyurethane layers, v) optionally applying a substrate layer to the polyurethane system components, vi) curing the polyurethane system components to form a polyurethane layer, and vii) separating the release layer from the top coat, wherein the overall thickness of the first and optionally further polyurethane layers is in the range from 0.01 to 20 mm and the polyurethane system components are solvent-free. The present invention further relates to an artificial leather obtainable by such a process and to the use of the artificial leather as upper materials for footwear.