Polyurethane Foam Pipe Insulation With Low Brittleness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pipes insulated with polyurethane foam face issues with brittleness, especially at the ends, due to the use of halogenated olefins as blowing agents, leading to increased sensitivity and potential destruction under low stresses, and existing blowing agents like HFCs have high global warming potential and are being phased out.
Innovation Solution
A process involving the use of aliphatic, halogenated hydrocarbon compounds with carbon-carbon double bonds and N,N-dialkylbenzylamine as a catalyst to produce polyurethane foam, which reduces brittleness and has a lower global warming potential, by mixing isocyanates with polyols and a blowing agent comprising compounds like trifluoropropenes, and introducing the reaction mixture into an annular gap between pipes to form the foam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If halogenated olefins are used as blowing agents to produce polyurethane foam, then the foam has good insulating properties, but the foam exhibits high brittleness and increased sensitivity leading to potential destruction under low stresses
Solution Approach 1:
The patent modifies the chemical structure of the blowing agent by using halogenated olefins with specific carbon-carbon double bond configurations and chain lengths (2-5 carbon atoms). This parameter change in the blowing agent structure results in polyurethane foam with altered cellular morphology and mechanical properties, specifically reducing brittleness while maintaining insulation performance
Solution Approach 2:
The invention creates a composite foam structure by combining polyurethane matrix with specifically structured halogenated olefin blowing agents. The resulting foam exhibits composite characteristics where the unique molecular structure of the blowing agent integrates into the polyurethane network, providing both thermal insulation and improved mechanical durability
2Loss of energy
If HFCs are used as blowing agents to produce polyurethane foam, then the foam has good insulating properties, but the blowing agents have high global warming potential and are being phased out
Solution Approach 1:
The patent employs halogenated olefins as alternative blowing agents that have lower global warming potential compared to HFCs. These compounds are designed to be environmentally friendly substitutes with shorter atmospheric lifetimes and reduced climate impact, while still delivering the required foaming performance and thermal insulation properties
Solution Approach 2:
The invention changes the chemical composition parameters of the blowing agent from conventional HFCs to specifically structured halogenated olefins with 2-5 carbon atoms and specific halogen substitution patterns. This parameter modification reduces the global warming potential while maintaining the blowing efficiency and insulation performance of the polyurethane foam
3Ease of manufacture
If conventional blowing agents are used to produce polyurethane foam, then the production process is simple, but the foam exhibits high brittleness at the ends of pipes
Solution Approach 1:
The patent modifies the blowing agent parameters by selecting halogenated olefins with specific molecular structures (2-5 carbon atoms, specific double bond positions). This parameter change affects the foaming kinetics and cell structure development, resulting in more uniform foam density throughout the pipe length, including the vulnerable end regions, thereby improving reliability without complicating the manufacturing process
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 results in polyurethane foam with improved mechanical properties, low brittleness, and reduced thermal conductivity, making it suitable for district heating or cooling networks with enhanced durability and environmental sustainability.
Implementation Method 1
physical blowing agents have a low boiling point which is attained as a result of the temperature increase in the exothermically reacting reaction mixture and thus these physical blowing agents go over into the gaseous state
Implementation Method 2
temperature increase in the exothermically reacting reaction mixture
Implementation Method 3
isocyanates are mixed with polyols... to give a reaction mixture, the reaction mixture is applied to a pipe for media and is allowed to cure to give the polyurethane foam
Implementation Method 4
catalyst comprising N,N-dialkylbenzylamine
Implementation Method 5
Pipes insulated with polyurethane foam... excellent insulating properties of the latter
Data Source
AI summary
Described herein is a process for producing a pipe insulated with polyurethane foam, where (a) isocyanates are mixed with (b) polyols, (c) blowing agent including at least one aliphatic, halogenated hydrocarbon compound (c1), made up of from 2 to 5 carbon atoms, at least one hydrogen atom and at least one fluorine and/or chlorine atom, where the compound (c1) includes at least one carbon-carbon double bond, (d) catalyst including N,N-dialkylbenzylamine, optionally (e) chain extenders and/or crosslinkers and optionally (f) auxiliaries and additives to give a reaction mixture, the reaction mixture is applied to a pipe for media and is allowed to cure to give the polyurethane foam. Also described herein is an insulated pipe obtained by such a process and a method of using such an insulated pipe as insulated composite wall pipe for district heating or district cooling networks laid in the ground.