One-component system comprising blocked polyurethane prepolymers
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Solution Overview
Problem
Existing one-component systems for producing artificial leathers and leather coatings fail to achieve sufficient tensile strengths, elongation values, and elastic moduli, and often generate toxic byproducts during curing.
Innovation Solution
A one-component system comprising a polyurethane prepolymer based on di- and/or polyisocyanate and di- and/or polyol, where the unconverted isocyanate groups are blocked with a malonic ester, and further includes a di- and/or polyamine, specifically using polyalkylene glycols and certain diisocyanates like IPDI for optimal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If blocked polyurethane prepolymers are used in one-component systems, then ease of operation and storage stability are improved, but tensile strength and mechanical properties deteriorate
Solution Approach 1:
The patent applies parameter changes by carefully selecting the molecular weight range of polyalkylene glycols (900-2150 g/mol) and controlling the NCO-OH ratio (1.05-1.20) to achieve optimal balance between storage stability and tensile strength. This specific parameter optimization resolves the contradiction by finding the precise operating window where both requirements are satisfied.
Solution Approach 2:
The patent uses composite materials by combining blocked polyurethane prepolymers with specific di- and polyamines, creating a hybrid system that leverages the stability of blocked prepolymers during storage while achieving superior tensile strength through the synergistic interaction with amine crosslinkers during curing.
2Stability of the object's composition
If conventional blocking agents are used, then storage stability is improved, but toxic byproducts are generated during curing
Solution Approach 1:
The patent converts the potential harm of toxic byproduct formation into a benefit by selecting malonic ester blocking agents that decompose into non-toxic or less toxic products during curing. This transforms the curing process from a harmful operation into a beneficial one, eliminating toxic emissions while maintaining storage stability.
Solution Approach 2:
The patent changes the chemical parameter of the blocking agent from conventional options (oximes, lactams) to malonic esters, which have fundamentally different decomposition pathways. This parameter change in the blocking agent chemistry eliminates toxic byproduct formation while preserving the storage stability function.
3Strength
If polyalkylene glycols with appropriate molecular weight are used, then tensile strength and elongation are improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the molecular weight parameter of polyalkylene glycols to a specific range (900-2150 g/mol) that delivers superior elongation properties. While this parameter specification adds some manufacturing complexity, it is offset by the use of commercially available materials and straightforward mixing procedures, achieving an acceptable balance between performance and manufacturability.
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 achieves good tensile strengths, elongation values, and elastic moduli, avoiding toxic byproduct formation during curing, and allowing for the production of artificial leathers and coatings with desirable mechanical properties.
Implementation Method 1
wherein all unconverted isocyanate groups of the polyurethane prepolymer are blocked with at least one malonic ester
Implementation Method 2
a one-component system comprising a polyurethane prepolymer based on di- and/or polyisocyanate and di- and/or polyol
Data Source
AI summary
The present invention relates to a one-component system comprisinga) at least one polyurethane prepolymer based on at least one di- and/or polyisocyanate and at least one di- and/or polyol, wherein at least one di- or polyol is a polyalkylene glycol having a number-average molecular weight of 900 to 2150 g/mol, wherein all unconverted isocyanate groups are blocked with at least one malonic ester andb) at least one di and/or polyamine;to a process for its production, to its use and to processes employing it for producing artificial leather and (artificial) leather coatings.