Polyether Polyols Mixed Alkene Oxide Core Segmentation
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Solution Overview
Problem
Current methods for producing biobased polyetherols using DMC-catalyzed addition reactions result in products with pure poly(ethylene oxide) or poly(propylene oxide) end blocks, leading to inhomogeneous and turbid products, limited suitability for molded polyurethane foams, and adverse effects on mechanical properties and processability.
Innovation Solution
A process involving multiple DMC-catalyzed addition reactions with varying alkylene oxide mixtures in distinct sections, ensuring constant composition for at least one minute, to produce polyetherols with a mixed alkylene oxide core and ethylene oxide end block, avoiding the formation of long poly(ethylene oxide) end blocks and enhancing reactivity and clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DMC-catalyzed addition reactions are used to produce biobased polyetherols, then the hydroxyl number can be set widely and biobased raw materials can be utilized, but the products become inhomogeneous and turbid with limited suitability for molded polyurethane foams
Solution Approach 1:
The patent applies segmentation by dividing the polyetherol molecule into distinct functional blocks: a core block with mixed alkylene oxides (EO/PO ratio 1:4 to 4:1) and terminal end blocks with pure ethylene oxide. This structural segmentation resolves the contradiction by creating homogeneous product regions (end blocks) while maintaining overall compositional flexibility through the mixed core block, enabling both wide hydroxyl number range and product clarity suitable for molded foams
Solution Approach 2:
The patent implements local quality by assigning different compositional characteristics to different parts of the polyetherol molecule. The terminal end blocks have pure ethylene oxide composition providing reactivity and clarity, while the core block has mixed alkylene oxide composition providing structural stability. This local differentiation allows the product to simultaneously achieve homogeneity in critical regions and overall adaptability in hydroxyl number
2Ease of manufacture
If pure poly(ethylene oxide) or poly(propylene oxide) end blocks are formed, then the addition reaction can be simplified, but the products become turbid and have adverse effects on mechanical properties and processability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the EO/PO ratio in the alkylene oxide mixture during the addition reaction. By maintaining specific ratio ranges (1:4 to 4:1) in the core block and using pure EO in end blocks, the product achieves optimal balance between manufacturing simplicity and mechanical reliability. This parameter optimization prevents turbidity while preserving reactivity and processability for molded foam applications
3Ease of operation
If long poly(ethylene oxide) end blocks are formed to enhance reactivity, then the polyetherol becomes more reactive, but the products become inhomogeneous and turbid
Solution Approach 1:
The patent applies preliminary action by pre-defining the core block composition with mixed alkylene oxides in specific ratios before forming the terminal end blocks. This preliminary structural arrangement creates a stable foundation that prevents phase separation and turbidity, allowing the subsequent addition of reactive ethylene oxide end blocks without compromising compositional stability. The pre-established core structure enables high reactivity while maintaining phase stability
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 process yields clear, phase-stable, and reactive polyetherols with improved mechanical properties and processability, suitable for producing highly elastic slabstock and molded flexible polyurethane foams, overcoming the limitations of previous methods.
Implementation Method 1
at least one hydroxyl-comprising fatty acid ester and/or at least one hydroxyl-modified fatty acid ester is reacted with the aid of a double metal cyanide catalyst in at least two process sections with in each case a mixture of ethylene oxide and at least one further alkylene oxide different from ethylene oxide
Data Source
AI summary
The present invention relates to a process for preparing polyether polyols, in which at least one hydroxyl-comprising fatty acid ester and/or at least one hydroxyl-modified fatty acid ester is reacted with the aid of a double metal cyanide catalyst in at least two process sections with in each case a mixture of ethylene oxide and at least one further alkylene oxide different from ethylene oxide.