Synthetic leather article and method for preparing same
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Solution Overview
Problem
Current 2K non-solvent PU foam technology faces challenges in achieving compatible adhesion with traditional PUD layers, leading to poor mechanical properties and appearance issues in synthetic leather production, particularly due to interference from additives in internally emulsified PUD systems.
Innovation Solution
A synthetic leather article comprising a top coating layer from internally emulsified polyurethane dispersion, a barrier layer from externally emulsified polyurethane dispersion, and a solvent-free 2K non-solvent PU foam layer, with the externally emulsified PUD acting as an adhesion-promoting layer between the top coating and the 2K non-solvent PU foam, enhancing compatibility and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If internally emulsified PUD is used as the top coating layer, then the coating provides good surface properties and patterns, but the adhesion strength between the top coating and 2K non-solvent PU foam is poor due to interference from additives in the internally emulsified PUD
Solution Approach 1:
The patent introduces an externally emulsified PUD coating layer as an intermediary between the internally emulsified PUD top coating and the 2K non-solvent PU foam. This intermediate layer acts as a buffer that does not interfere with the polyurethane curing reaction, allowing the top coating to maintain its surface properties while enabling proper adhesion to the foam layer through the chemically compatible intermediate layer.
Solution Approach 2:
The patent segments the coating structure into three distinct layers: (A) internally emulsified PUD top coating for surface properties, (B) externally emulsified PUD intermediate layer for adhesion promotion, and (C) 2K non-solvent PU foam for mechanical properties. This segmentation allows each layer to perform its specific function without interfering with others, resolving the adhesion conflict.
2Ease of manufacture
If 2K non-solvent PU foam technology is used, then the manufacturing cost is reduced and formulation flexibility is increased, but compatibility and adhesion with traditional PUD layers are poor leading to weak mechanical properties
Solution Approach 1:
The externally emulsified PUD layer serves as a chemical bridge between the cost-effective 2K non-solvent PU foam and the traditional internally emulsified PUD coating. This intermediate layer is formulated to be chemically compatible with both systems, enabling the foam to cure properly and bond effectively, thereby achieving good mechanical properties while maintaining the economic advantages of 2K foam technology.
Solution Approach 2:
The patent changes the emulsification parameter of the intermediate layer from internal to external emulsification. This parameter change makes the intermediate layer chemically compatible with the 2K non-solvent PU foam system, allowing the foam to cure properly and achieve strong mechanical properties while maintaining the cost and formulation flexibility benefits of the 2K foam technology.
3Object-affected harmful factors
If aqueous PUD systems are used instead of volatile organic solvents, then environmental friendliness and health safety are improved, but adhesion strength between the coating layer and 2K non-solvent PU foam deteriorates
Solution Approach 1:
The patent uses an externally emulsified PUD layer as an intermediary that maintains the environmental benefits of aqueous systems while resolving the adhesion problem. This intermediate aqueous layer is chemically compatible with the 2K non-solvent PU foam, allowing strong adhesion to form without requiring volatile organic solvents, thus preserving both environmental friendliness and adhesion strength.
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 solution results in superior delamination resistance and mechanical properties comparable to solvent-based systems, suitable for various applications such as automotive and footwear, while maintaining an eco-friendly solvent-free process.
Implementation Method 1
the externally emulsified PUD acting as an adhesion-promoting layer between the top coating and the 2K non-solvent PU foam, enhancing compatibility and mechanical properties
Implementation Method 2
internally emulsified PUD, which refers to PUD emulsified by surfactant groups, particularly ionic surfactant groups covalently attached to the backbone chain of the polyurethane
Implementation Method 3
the externally emulsified PUD, which refers to PUD mainly emulsified by surfactants that are not covalently attached to the backbone chain of the polyurethane
Implementation Method 4
performing polyurethane reaction and simultaneously foaming the resultant polyurethane so as to form the formed PU resin
Implementation Method 5
simultaneously foaming the resultant polyurethane so as to form the formed PU resin
Data Source
AI summary
A synthetic leather article comprising a top coating derived from an internally emulsified PUD, a barrier layer derived from an externally emulsified PUD and a 2K non-solvent PU foam layer is provided. The leather article exhibits high delamination resistance while retaining superior mechanical properties and appearance comparable with those derived from the organic solvent-based PU. A method for preparing the synthetic leather article is also provided.