Extruded Polystyrene Foam Blowing Agents
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Solution Overview
Problem
Current fluorocarbon-based blowing agents, such as HFCs, have high global warming potentials and thermal conductivity, making them less desirable for foam insulation, while alternatives like hydrocarbon blowing agents lack thermal insulation efficiency and are flammable, posing environmental and safety concerns.
Innovation Solution
A foamable composition comprising trans-HFO-1234ze and trans-HCFO-1233zd, within specific weight percentages, is used to create closed-cell extruded polystyrene foams with low density and improved thermal insulation, maintaining environmental safety and compatibility with conventional foam generating systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HFC blowing agents are used, then foam insulation performance is improved, but global warming potential increases
Solution Approach 1:
The patent changes the chemical composition parameters of the blowing agent from conventional HFCs to a specific mixture of HFO-1234ze and HCFO-1233zd in controlled weight percentages. This parameter change maintains the desired foam insulation performance while significantly reducing the global warming potential from typical HFC values to below 150 GWP
Solution Approach 2:
The patent creates a composite blowing agent system by combining two different fluorocarbon compounds (HFO-1234ze and HCFO-1233zd) in specific proportions. This composite approach allows the mixture to achieve both low GWP and adequate foam performance, balancing environmental concerns with functional requirements
2Object-affected harmful factors
If hydrocarbon blowing agents are used, then global warming potential is reduced, but flammability increases
Solution Approach 1:
The patent changes the chemical structure parameters by using fluorocarbon compounds (HFO and HCFO) instead of hydrocarbons. This parameter change maintains low GWP similar to hydrocarbons while eliminating the flammability issue through the presence of fluorine atoms in the molecular structure
3Productivity
If HFC blowing agents are used, then foam formation is effective, but thermal conductivity increases
Solution Approach 1:
The patent changes the physical parameters of the blowing agent by selecting HFO-1234ze and HCFO-1233zd with specific molecular weights and vapor pressures. These parameter changes result in lower thermal conductivity of the foam cells while maintaining effective foam formation through controlled expansion characteristics
4Object-affected harmful factors
If chlorine-containing compounds are replaced, then ozone depletion is reduced, but performance properties may deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by replacing chlorine-containing compounds with chlorine-free fluorocarbons (HFO and HCFO). This eliminates ozone depletion potential while maintaining desirable foam characteristics through careful selection of the blowing agent mixture ratio and its physical properties
Solution Approach 2:
The patent employs a composite blowing agent system combining HFO-1234ze and HCFO-1233zd to replicate the performance properties previously achieved with chlorine-containing compounds. The composite mixture provides balanced foam cell structure, expansion ratio, and thermal insulation without ozone-depleting substances
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 composition achieves low-density, thermally insulating foams with reduced global warming potential and flammability, enhancing processing advantages and maintaining performance comparable to traditional HFC-based foams, while being environmentally friendly and non-toxic.
Implementation Method 1
The physical blowing agents typically are dissolved in the polymer or polymer precursor material and then expand volumetrically (again at a predetermined temperature/pressure) to contribute to the formation of the foamed structure
Implementation Method 2
maintaining the desired performance in use properties... imparting excellent thermal insulating properties
Data Source
Figure 1
AI summary
Foamable composition comprising a) foamable resin, comprising foamable polystyrene; and (b) a blowing agent comprising (i) trans-1,3,3,3-tetrafluoropropene (transHFO-1234ze) in an amount greater than about 3% by weight to less than about 8% by weight of the foamable composition; and (ii) greater than about 2% by weight of trans-1, 1, 1 -trifluoro-3-chloropropene (transHCFO-1233zd) in the foamable composition, provided that concentration of component (i) and (ii) together in the foamable composition is not greater than about 15% of the foamable composition. An extruded polystyrene foam is made form the foamable composition.