Artificial leather with improved flexing endurance properties
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Solution Overview
Problem
Existing methods for producing artificial leather, such as the dry and wet processes, consume significant amounts of solvents, harming the environment, and do not meet the high mechanical and visual requirements needed for footwear applications, particularly in terms of surface constitution, gloss, color, and resistiveness.
Innovation Solution
A solvent-free process involving a release layer, application of a top coat and polyurethane system components comprising isocyanate and polyol components with specific NCO content and isocyanate index, followed by curing and separation, to form a polyurethane layer with a thickness range of 0.01 to 20 mm, ensuring excellent mechanical properties and adherence.
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 surface constitution (gloss, color, resistiveness) deteriorates
Solution Approach 1:
The patent divides the artificial leather structure into multiple functional layers: a top coat layer (1-500 μm) applied to the polyurethane layer, and optionally a substrate layer. This segmentation allows the solvent-free polyurethane system to provide mechanical strength while the top coat layer specifically addresses surface constitution requirements for gloss, color, and resistiveness.
Solution Approach 2:
The patent uses composite material structure combining polyurethane system components (isocyanate component A and polyol component B) with a top coat layer. The polyurethane layer provides mechanical properties and environmental friendliness, while the top coat layer enhances surface constitution, creating a composite material that satisfies both requirements simultaneously.
2Manufacturing precision
If top coat is applied to improve surface constitution, then gloss and color are improved, but adherence between top coat and polyurethane layer deteriorates
Solution Approach 1:
The patent specifies precise parameter ranges for the polyurethane system: isocyanate index of 101-140, NCO content of 10-25% by weight in the isocyanate component. These parameter optimizations ensure the polyurethane layer has optimal surface properties and chemical reactivity to bond with the top coat, maintaining strong adherence while allowing surface constitution improvement.
Solution Approach 2:
The top coat acts as an intermediary layer that chemically bonds to both the polyurethane layer below and provides the desired surface properties. The controlled interaction between the isocyanate groups in the polyurethane and the top coat materials creates a strong interface, preventing delamination while enabling surface enhancement.
3Strength
If polyisocyanate prepolymers with specific NCO content are used, then mechanical properties are improved, but surface resistiveness deteriorates
Solution Approach 1:
The patent segments the functional requirements by placing the mechanical property enhancement in the polyurethane layer (through optimized isocyanate index and NCO content) and the surface resistiveness enhancement in the top coat layer, allowing each layer to specialize in its respective function without compromise.
Solution Approach 2:
The composite structure of polyurethane layer plus top coat layer enables the polyurethane to provide mechanical strength through optimized isocyanate content while the top coat layer provides the surface resistiveness, combining the advantages of both material systems.
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 produces artificial leather with superior mechanical properties, including flexing endurance, and excellent adherence between the top coat and polyurethane layers, meeting the demanding requirements for footwear applications while being environmentally friendly.
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
Implementation Method 2
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.