Non-Toxic Polyurethane Casting Mass for Hollow Fiber Embedding
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Solution Overview
Problem
Current polyurethane casting compounds for embedding hollow fibers in filter elements face challenges with storage stability, reactivity consistency, and toxicity, particularly with tin-based catalysts, which affect curing times and productivity, and existing alternatives either have low reactivity or lead to viscosity issues that hinder optimal impregnation.
Innovation Solution
A polyurethane casting compound is formed by mixing a fatty acid-based polyol component with a hydroxyl number of 50 to 500 mg KOH/g and an amine compound containing a tertiary nitrogen atom with a metal catalyst, such as bismuth, that does not include tin, lead, or mercury, ensuring consistent reactivity and stability without toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tin-based catalysts are used to achieve fast curing and high productivity, then curing speed and productivity are improved, but storage stability deteriorates and toxic potential increases
Solution Approach 1:
The patent changes the chemical parameter of the catalyst by replacing tin-based catalysts with alternative catalysts such as bismuth, zinc, or calcium compounds. This parameter change maintains the catalytic function for fast curing while eliminating the storage stability issues and toxicity associated with tin catalysts, thereby resolving the contradiction between productivity and storage stability
Solution Approach 2:
The patent employs catalysts that are less stable over time (short-living in terms of catalyst activity) but non-toxic and suitable for medical applications. The catalyst system is designed to provide sufficient activity during the short processing window while not compromising long-term storage stability or patient safety
2Productivity
If amine catalysts are used to achieve fast curing, then productivity is improved, but migration behavior increases and they leach out of the polyurethane
Solution Approach 1:
The patent extracts the harmful migration property from the catalyst system by selecting metal catalysts (bismuth, zinc, calcium) that are immobilized in the polyurethane matrix and do not leach out, while retaining the fast curing capability through their catalytic activity on the polyol-isocyanate reaction
3Stability of the object's composition
If conventional catalysts are used to maintain consistent reactivity during storage, then curing consistency is improved, but toxic potential increases
Solution Approach 1:
The patent changes the chemical composition parameter from toxic tin-based catalysts to non-toxic alternatives (bismuth, zinc, calcium compounds) while maintaining their catalytic function. This ensures consistent reactivity during storage and processing without introducing toxic potential, resolving the contradiction between reactivity consistency and safety
4Stability of the object's composition
If storage duration increases, then reactivity consistency deteriorates with conventional catalysts, but productivity is affected
Solution Approach 1:
The patent inverts the conventional approach by using catalysts that are specifically selected for their stability over storage time. Instead of accepting catalyst degradation as inevitable, the patent chooses metal catalysts (bismuth, zinc, calcium) that maintain their catalytic activity and provide consistent reactivity even after extended storage periods, thereby protecting productivity
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 storage-stable, fast-reacting, and non-toxic polyurethane casting compound that maintains optimal impregnation and curing behavior, suitable for medical applications like dialysis filters, with improved hydrophobicity and resistance to disinfectants, allowing for efficient production and sterilization.
Implementation Method 1
the polyol component (A) contains (a1) at least one fatty acid-based polyol, (a2) at least one amine compound with at least one tertiary nitrogen atom and at least one hydrogen atom reactive towards isocyanate, and (a3) at least one metal compound acting as a polyurethane catalyst
Implementation Method 2
at least one amine compound with at least one tertiary nitrogen atom and at least one hydrogen atom reactive towards isocyanate
Data Source
AI summary
The present invention relates to polyurethane potting compounds for embedding of hollow fibres of filter elements. These are obtainable by mixing a polyol component (A) and an isocyanate component (B) to afford a reaction mixture and reacting the mixture to afford the polyurethane potting compound, wherein the polyol component (A) (a1) contains at least one fatty acid-based polyol, (a2) at least one amine compound having at least one tertiary nitrogen atom and at least one isocyanate-reactive hydrogen atom and (a3) at least one metal compound which acts as a polyurethane catalyst, wherein the polyurethane catalyst (a3) contains no tin, lead and/or mercury, and the isocyanate component (B) contains at least one aromatic isocyanate having at least two isocyanate groups. The present invention further relates to a process for producing filter elements using the polyurethane potting compounds and to the use of the polyurethane potting compounds for embedding of hollow fibres.