Foamed Polymeric Composition with Supercritical CO2 for Low VOC
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Solution Overview
Problem
Existing foamed polymeric compositions, particularly pressure-sensitive adhesive tapes, face challenges with high volatile organic compound (VOC) levels, complexity in manufacturing, and lack of versatility and formulation flexibility, which are not adequately addressed by current methods such as using expandable microspheres or specific rubber-based materials.
Innovation Solution
An extrusion apparatus comprising a planetary roller extruder, melt pump, static cooling mixer, and foaming equipment is used to process a polymeric composition with a physical foaming agent in supercritical conditions, allowing for efficient devolatilization and foaming, resulting in low VOC foamed polymeric compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If expandable microspheres are used for foaming polymeric compositions, then foaming capability is improved, but VOC content increases
Solution Approach 1:
The patent changes the physical state and chemical composition parameters by using a physical foaming agent (carbon dioxide) instead of expandable microspheres. This substitution fundamentally alters the foaming mechanism from chemical expansion of microspheres to physical dissolution and expansion of gas, thereby achieving low VOC content while maintaining foaming capability.
Solution Approach 2:
The patent converts the potentially harmful effect of using foaming agents into a benefit by selecting a physical foaming agent (carbon dioxide) that eliminates VOC emissions. The foaming process that previously caused harm through microsphere decomposition is transformed into a beneficial process that reduces harmful emissions while achieving the desired foam structure.
2Object-generated harmful factors
If specific rubber-based polymeric material is used to reduce VOC levels, then VOC content is reduced, but formulation flexibility decreases
Solution Approach 1:
The patent changes the formulation approach by using a physical foaming agent (carbon dioxide) instead of being constrained to specific rubber-based polymeric materials. This parameter change in the foaming mechanism allows for broader formulation flexibility while maintaining low VOC levels, as the physical foaming process is compatible with various polymer systems rather than requiring specific rubber-based materials.
3Object-generated harmful factors
If thorough devolatilization process is implemented, then VOC levels are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating carbon dioxide as a physical foaming agent during the extrusion process itself, rather than requiring subsequent devolatilization steps. The foaming and VOC reduction occur simultaneously during manufacturing, eliminating the need for separate thorough devolatilization processes and thereby reducing manufacturing complexity.
4Shape
If conventional foaming methods are used, then foaming capability is maintained, but adhesion performance at elevated temperatures deteriorates
Solution Approach 1:
The patent changes the foaming mechanism from chemical (expandable microspheres) to physical (carbon dioxide dissolution and expansion), which creates a more uniform and controlled foam structure. This parameter change in the foaming process improves the consistency of the foam cells and their bonding to substrates, thereby enhancing adhesion performance at elevated temperatures while maintaining foaming capability.
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 achieves VOC levels below 400 ppm, providing stable and cost-effective foamed polymeric compositions suitable for industrial applications, particularly in construction, automotive, and electronic industries, with improved adhesion and reduced odor.
Implementation Method 1
mixing the hot melt processable polymeric composition and the physical foaming agent in the extrusion apparatus thereby forming a precursor
Implementation Method 2
exposing the hot melt processable polymeric composition to increased pressure and temperature conditions
Implementation Method 3
exposing the composition to a reduced pressure, whereby the physical bowing agent expands resulting in foaming of the precursor
Implementation Method 4
a melt pump arranged downstream of the extruder
Implementation Method 5
a static cooling mixer equipment arranged downstream of the melt pump
Data Source
AI summary
The present disclosure relates to an extrusion apparatus comprising: a) a planetary roller extruder; b) a melt pump arranged downstream of the extruder; c) optionally, a fluid feeding equipment; d) a static cooling mixer equipment arranged downstream of the melt pump; e) a foaming equipment arranged downstream of the static cooling mixer equipment. The present disclosure also relates to a process of manufacturing a foamed polymeric composition and uses thereof.