Polystyrene Foam Extrusion Using Adipate Esters and CO2 Blowing Agents
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Solution Overview
Problem
The production of extruded polystyrene foams using traditional halocarbon blowing agents faces challenges due to environmental concerns, such as ozone layer depletion and global warming, and alternative agents like carbon dioxide and hydrocarbons pose difficulties in solubility, processability, and safety issues, leading to suboptimal foam properties.
Innovation Solution
The use of a combination of atmospheric gases, hydrocarbons, alcohols, HFCs, and water as a blowing agent system, in conjunction with adipate esters as polymer processing aids, particularly bis(n-decanyl) adipate, to improve the solubility and processability of carbon dioxide and other blowing agents in polystyrene melts, enhancing the production of extruded polystyrene foams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional halocarbon blowing agents are used, then foam appearance and properties are improved, but environmental harm increases due to ozone layer depletion and global warming
Solution Approach 1:
The patent removes harmful halocarbon blowing agents from the foam production process and replaces them with environmentally benign alternatives such as carbon dioxide, water, and hydrocarbons. This extraction of the harmful substance while maintaining the essential foaming function resolves the contradiction between foam quality and environmental protection.
Solution Approach 2:
The patent converts potentially harmful or problematic blowing agents into beneficial ones by using carbon dioxide and water that leave no residual harm, and by employing polymer processing aids that improve foam quality while enabling the use of these environmentally friendly blowing agents. The harmful aspect is transformed into a benefit through careful selection and combination of materials.
2Object-affected harmful factors
If carbon dioxide and hydrocarbons are used as blowing agents, then environmental harm is reduced, but solubility and processability in polystyrene melt deteriorate
Solution Approach 1:
The patent introduces polymer processing aids as intermediary substances that facilitate the dissolution and uniform distribution of carbon dioxide and hydrocarbon blowing agents in the polystyrene melt. These processing aids act as mediators that improve solubility and processability without compromising the environmental benefits of using non-halocarbon blowing agents.
Solution Approach 2:
The patent creates a composite system combining polystyrene, blowing agents (carbon dioxide, hydrocarbons, water), and polymer processing aids. This composite approach leverages the synergistic effects of multiple components to achieve both environmental friendliness and manufacturing ease, as the processing aids enhance the overall system's ability to incorporate and process the alternative blowing agents.
3Object-affected harmful factors
If carbon dioxide and hydrocarbons are used as blowing agents, then environmental harm is reduced, but safety issues increase due to flammability and volatility
Solution Approach 1:
The patent combines multiple blowing agents (carbon dioxide, hydrocarbons, water) and polymer processing aids in specific proportions to create a blended system. This merging dilutes the concentration of highly flammable components while maintaining the environmental benefits, and the processing aids contribute to safer processing by improving melt stability and reducing the risk of premature foaming or safety incidents.
Solution Approach 2:
The patent optimizes process parameters such as temperature, pressure, and additive concentrations to enhance safety during processing. By carefully controlling these parameters and selecting appropriate polymer processing aids, the patent reduces the volatility and flammability risks associated with hydrocarbon blowing agents while maintaining their environmental advantages.
4Ease of manufacture
If polymer processing aids are added to improve solubility of blowing agents, then manufacturing ease is improved, but process complexity increases
Solution Approach 1:
The patent employs polymer processing aids that are used in small, controlled amounts and serve their purpose of improving solubility and processability during the extrusion process. These aids are incorporated into the foam structure in minimal quantities, simplifying the overall process by enabling efficient blowing agent dissolution without requiring complex additional equipment or multi-step procedures.
Data Source
AI summary
Disclosed is a method for making polystyrene foam which utilizes one or more atmospheric gases, particularly combinations of HFCs and CO2, as the blowing system in combination with a polymer processing aid (PPA), typically an ester that is relatively non-volatile at the extrusion temperature range. The blowing system and the PPA may both be introduced into the molten thermoplastic polystyrene resin or the PPA may be incorporated in the solid source polystyrene resins. The resulting foams will typically exhibit improved dimensional stability at ambient temperatures.