Solvent-Free Polyurethane System for UV-Resistant Artificial Leather
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Solution Overview
Problem
Existing methods for producing artificial leather using solvent-based systems face issues such as odor generation, chemical resistance, and energy-intensive solvent recovery, while solvent-free systems often suffer from mechanical property deficiencies and UV-induced color changes.
Innovation Solution
A solvent-free multi-component system comprising cycloaliphatic diamines and (cyclo)aliphatic homopolymeric polyisocyanates with isocyanurate groups, allowing for UV-resistant, heat-resistant, and odorless artificial leather production through controlled reaction rates and curing times, enhancing mechanical properties and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solvent-based systems are used for producing artificial leather, then the production process is established and porous leather-like polyurethane layer is obtained, but odor is generated and toxic organic solvent volatility causes environmental and health issues requiring energy-intensive solvent recovery
Solution Approach 1:
The patent removes the harmful organic solvent component from the polyurethane formulation entirely, transitioning from a solvent-based system to a solvent-free system. This extraction of the harmful element eliminates odor generation and toxic emissions while maintaining the core polyurethane production process through alternative chemistry using polyol, polyisocyanate, and additive combinations that cure without requiring solvent evaporation or recovery
Solution Approach 2:
The patent changes the chemical composition parameters of the polyurethane system by selecting specific combinations of polyols (with particular OH numbers and molecular weights), polyisocyanates (with specific NCO contents), and additives (catalysts, stabilizers, pigments) in controlled ratios. This parameter optimization enables the solvent-free system to achieve proper curing, mechanical properties, and processing characteristics without organic solvents, thereby eliminating harmful emissions while maintaining manufacturability
2Object-generated harmful factors
If aqueous-based systems are used to avoid organic solvents, then no organic solvent emissions occur, but water removal requires high-energy furnaces and the polyurethane layer has reduced chemical resistance and abrasion resistance
Solution Approach 1:
The patent changes the formulation parameters by using solvent-free polyol-polyisocyanate systems with specific molecular weights, OH numbers, and NCO contents that enable low-temperature or ambient curing. This eliminates the need for high-energy furnace drying required by aqueous systems, as the solvent-free chemistry proceeds through direct polyurethane formation and crosslinking without requiring bulk water evaporation, thereby reducing energy consumption while maintaining chemical resistance
3Ease of manufacture
If aromatic isocyanates are used in solvent-free 2K systems, then solvent-free production is achieved, but odors develop after production and color changes occur after UV radiation
Solution Approach 1:
The patent changes the chemical structure parameter of the isocyanate component by selecting aliphatic or cycloaliphatic polyisocyanates instead of aromatic isocyanates. These alternative isocyanates have molecular structures that do not undergo UV-induced yellowing reactions and do not generate unpleasant odors upon curing or aging. The specific selection of polyisocyanates with controlled NCO content and molecular weight maintains the reactivity and curing characteristics needed for solvent-free production while achieving superior color stability and odor resistance
Solution Approach 2:
The patent converts the potential harm of UV degradation and odor generation (inherent to aromatic isocyanates) into a benefit by selecting isocyanate types that are inherently resistant to these degradation mechanisms. The aliphatic/cycloaliphatic structures provide natural UV stability and odor resistance, turning what would be a chemical limitation into a performance advantage for long-term durability and aesthetic stability
4Stability of the object's composition
If cycloaliphatic diamines and (cyclo)aliphatic homopolymeric polyisocyanates are used in solvent-free multi-component system, then UV resistance, heat resistance, and odor resistance are improved, but formulation complexity increases
Solution Approach 1:
The patent achieves multi-functionality by selecting polyisocyanates and polyols that simultaneously provide multiple desired properties: the (cyclo)aliphatic homopolymeric polyisocyanates with isocyanurate groups provide both UV resistance and adequate reactivity, while the polyol selection (with specific OH numbers and molecular weights) concurrently ensures proper mechanical properties and curing characteristics. The additive package (catalysts, stabilizers, pigments) is optimized to work synergistically with these base components, reducing the need for separate specialized additives and simplifying the overall formulation despite the high performance requirements
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 system produces artificial leather films with improved mechanical properties, UV resistance, and chemical resistance, reducing odor and energy consumption, suitable for various applications like shoes, handbags, and automotive interiors.
Implementation Method 1
a linear polymer prepared by polyaddition of diisocyanate and the same molar amount of a polymer diol
Implementation Method 2
The reaction rate and the curing time or curing temperature can be controlled by adding a cycloaliphatic amine component
Implementation Method 3
formulations can be produced with which artificial leather films can be produced by a 2K process without the use of solvents, which are very UV-resistant, heat-resistant and odorless
Data Source
AI summary
The present invention relates to solvent-free multi-component systems, methods for their production, their use for the production of artificial leather and methods using them for the production of hardened masses.