Polyurethane Composite Surface for Thermoplastic Embossing
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Solution Overview
Problem
Existing polyurethane layers in composite structures are highly stable due to cross-linking, making them unable to be thermoplastically embossed, which limits their use and flexibility.
Innovation Solution
A polyurethane layer with a specific structure, comprising bifunctional and trifunctional polyols, is developed, allowing for thermoplastic embossability while maintaining mechanical stability, with a solvent content of less than 1% and a molar ratio of bifunctional to trifunctional polyols between (1/5) to (30/1), enabling subsequent shaping of fine structures like grain patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane layers are highly cross-linked to achieve mechanical stability, then stability and durability are improved, but thermoplastic embossability is lost
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molar ratio of bifunctional to trifunctional polyols within (1/5) to (30/1), and adjusting the solvent content to less than 1%. This optimization creates a polyurethane layer with balanced cross-linking density that maintains mechanical stability while preserving sufficient thermoplasticity for embossing operations.
Solution Approach 2:
The invention uses a composite polyol system combining bifunctional and trifunctional polyols in specific proportions. The bifunctional polyol provides linear chain growth for flexibility, while the trifunctional polyol introduces controlled cross-linking for stability. This composite approach achieves both embossability and mechanical durability simultaneously.
2Object-generated harmful factors
If solvent content is reduced to less than 1% for environmental reasons, then volatile organic compound emissions are reduced, but processing and application properties may worsen
Solution Approach 1:
The patent maintains processing ease despite low solvent content by optimizing the polyol molecular weight and hydroxyl value parameters. The specific ratio of bifunctional to trifunctional polyols ensures appropriate viscosity and reactivity, allowing the coating to remain processable with minimal solvent (less than 1%) while achieving good application properties and rapid curing.
3Adaptability or versatility
If the molar ratio of bifunctional to trifunctional polyols is optimized for embossability, then thermoplastic shaping is enabled, but cross-linking density and mechanical strength may be compromised
Solution Approach 1:
The patent resolves this contradiction by defining a specific molar ratio range of bifunctional to trifunctional polyols from (1/5) to (30/1). This parameter optimization ensures sufficient cross-linking density for mechanical strength while maintaining enough linear chain structures for thermoplastic deformability during embossing, achieving both strength and shaping capability.
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 provides a polyurethane layer that is both thermoplastically embossable and mechanically stable, allowing for the formation of detailed structures and improved durability, with reduced volatile organic compound emissions and enhanced adhesive properties, suitable for artificial leather applications.
Implementation Method 1
thermoplastically embossable, which allows a scar, seam, embossing or shaping corresponding to a leather to be produced
Implementation Method 2
Polyurethanes are polymers that are created by linking isocyanate groups with alcohols. This reacts according to the following equation a): residue 1-OH + OCN residue 2 = residue 1-O-CO-NH residue 2
Data Source
AI summary
The invention relates to a flat, flexible composite structure with a polyurethane surface, having at least one polyurethane layer based on a polyurethane of the formula -[-O-Ra-O-CO-NH-Rb-NH-CO]n- (I) where mean : - -O-Ra-O- the residues of at least two aliphatic polyols with hydroxyl functionalities, - the polyols being bifunctional and trifunctional polyols, - Rb the residue of an aliphatic isocyanate-terminated isocyanate-polyol adduct, - n an integer from 1 to 50,000, whereby the at least one polyurethane layer is designed to be low in solvents, preferably solvent-free, the molar ratio (bifunctional polyols/trifunctional polyols) (1/5) to (30/1), preferably (1/1) to ( 20/1), particularly preferably (2.5/1) to (15/1) and the rest of the trifunctional polyol has a structure corresponding to the formula (II), in which - radicals R1 independently of one another an organic, aliphatic radical with a denote a linking chain of 1 to 4 carbon atoms, - residue R2 denotes an organic, aliphatic residue with a linking chain of 1 to 4 carbon atoms and - the linking chain of carbon atoms of the residue R2 is at least as long as the linking one Chain of carbon atoms of one of the residues R1.