Polyetherester Polyols for Rigid PU Foam Compressive Strength
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Solution Overview
Problem
Rigid polyurethane foams obtained using conventional polyol components with high functionalities and low molecular weights have poor solubility for blowing agents and inadequate mechanical properties, particularly compressive strength, which limits their suitability for insulation and refrigeration applications.
Innovation Solution
A polyol component comprising 20-40 wt% of polyetherester polyols with specific functionalities and hydroxyl numbers, combined with 20-40 wt% of polyether polyols and 20-40 wt% of polyether polyols, along with catalysts and auxiliaries, to enhance solubility, flowability, and mechanical properties when reacted with di- or polyisocyanates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyols with high functionality and low molecular weight are used to ensure high crosslinking degree, then the crosslinking degree is improved, but the solubility for blowing agents deteriorates
Solution Approach 1:
The patent introduces polyetherester polyols with specific molecular weight ranges (500-5000 g/mol) and functionality (3-8), changing the physical-chemical parameters of the polyol component. This resolves the contradiction by finding an optimal parameter range that provides sufficient crosslinking while maintaining blowing agent solubility through the ester groups' polar interactions
Solution Approach 2:
The patent creates a composite polyol system combining polyetherester polyols with conventional polyether polyols in specific ratios (20-70 wt% and 30-80 wt% respectively). This composite approach allows the polyetherester component to provide crosslinking sites while the polyether component maintains solubility, thus resolving the contradiction between crosslinking degree and blowing agent solubility
2Stability of the object's composition
If polyols with very high functionality and high hydroxyl numbers are used, then the crosslinking degree is improved, but the viscosity increases
Solution Approach 1:
The patent specifies polyetherester polyols with molecular weights of 500-5000 g/mol and functionalities of 3-8, optimizing these parameters to achieve adequate crosslinking density while keeping viscosity manageable for processing. The controlled parameter range prevents excessive viscosity buildup
Solution Approach 2:
The patent uses polyetherester polyols containing ester groups that provide localized polar interactions for crosslinking, rather than relying on high overall functionality throughout the entire polyol molecule. This localized approach to crosslinking capability maintains lower overall viscosity while achieving sufficient crosslink density at critical sites
3Object-affected harmful factors
If polyether alcohols with functionalities of 2 to 4 and hydroxyl numbers of 100 to 250 are added to improve blowing agent solubility, then the solubility is improved, but the flowability deteriorates
Solution Approach 1:
The patent employs a composite polyol formulation where polyetherester polyols (20-70 wt%) provide blowing agent solubility through ester group interactions, while conventional polyether polyols (30-80 wt%) with appropriate molecular weights maintain reaction mixture flowability. This composite approach balances solubility enhancement with flowability preservation
Solution Approach 2:
The patent optimizes the molecular weight and functionality parameters of the polyetherester polyol component to achieve adequate blowing agent solubility without excessive viscosity increase. By controlling these parameters within specific ranges, the patent improves solubility while minimizing the negative impact on flowability
4Strength
If formulations eschew additional polyether alcohol with functionality of 2 to 4 and hydroxyl numbers of 100 to 250, then the mechanical properties are improved, but the demolding properties deteriorate
Solution Approach 1:
The patent specifies polyetherester polyols with molecular weights of 500-5000 g/mol and functionalities of 3-8, along with polyether polyols having complementary parameters. This optimized parameter combination achieves high compressive strength through adequate crosslinking while maintaining demolding properties through controlled reaction kinetics and foam structure
Solution Approach 2:
The patent creates a composite polyol system combining polyetherester polyols with conventional polyether polyols in specific ratios. This composite formulation achieves the dual benefit of improved mechanical properties (compressive strength) and adequate demolding properties, resolving the contradiction present in formulations that completely exclude lower functionality polyols
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 rigid polyurethane foams with improved compressive strength and demolding properties, ensuring better performance in insulation and refrigeration applications while maintaining high solubility for blowing agents.
Implementation Method 1
reacting organic polyisocyanates with one or more compounds having two or more reactive hydrogen atoms, preferably polyether and/or polyester alcohols (polyols)
Implementation Method 2
have a very high level of viscosity. It is further known that such polyols are comparatively polar and thus have poor solubility for customary blowing agents
Data Source
AI summary
A polyol component b) comprising:20 to 40 wt % of polyetherester polyols B) having a functionality of 3.8 to 4.8, an OH number of 380 to 440 mg KOH/g and a fatty acid and/or fatty acid ester content of 8 to 17 wt %, based on the weight of polyetherester polyols B);20 to 40 wt % of polyether polyols C) having a functionality of 3.7 to 4 and an OH number of 300 to 420 mg KOH/g;20 to 40 wt % of one or more polyether polyols D) having a functionality of 4.5 to 6.5 and an OH number of 400 to 520 mg KOH/g;0.5 to 5.5 wt % of catalysts E),0.1 to 5 wt % of further auxiliaries and/or added-substance materials F),0.5 to 5 wt % of water G);and also rigid polyurethane foams obtained therewith and use thereof for insulation and refrigeration applications.