Polymeric Foam Core Sandwich Articles Using Recycled Polymer Flakes
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Solution Overview
Problem
Current methods for producing polymeric foam core sandwich articles using recycled polymers are costly due to the need for expensive processing steps, such as pelletization and the use of polymers in powder or particulate form, which increase production costs.
Innovation Solution
A process involving a female mould with heating and cooling means, where thermoplastic polymers and a blowing agent are layered in batches, with the second batch containing a mixture of polymeric material and blowing agent, and the first and third batches comprising recycled polymer flakes, allowing for the production of polymeric articles with a high percentage of recycled content without pelletization or fine grinding, thus reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recycled polymers are processed through pelletization or converted to powder/particulate form, then they can be used in foam core sandwich articles, but the production cost increases significantly
Solution Approach 1:
The invention changes the physical state parameter of recycled polymers from processed pellets/powder to shredded flakes, eliminating expensive pelletization steps while maintaining usability in the moulding process
Solution Approach 2:
The invention uses shredded flake form of recycled polymers that can be directly moulded without requiring expensive reprocessing into pellets, effectively using a lower-cost material form that achieves the same functional result
2Manufacturing precision
If polymers are used in powder or particulate form, then they can fill the mould cavity effectively, but the overall production cost increases
Solution Approach 1:
The invention changes the particle size and shape parameter from fine powder/particulate to larger shredded flakes, which achieve effective mould filling without requiring the expensive processing steps needed to create fine powders
3Reliability
If expensive processing steps like alcoholysis or hydrolysis are applied to broken polymer chains, then high quality polymers can be produced, but the process becomes very expensive
Solution Approach 1:
The invention extracts and eliminates the expensive chemical recovery steps (alcoholysis, hydrolysis) from the recycling process, using shredded flakes directly in moulding without breaking down polymer chains chemically
Solution Approach 2:
The invention accepts lower-grade recycled polymers in shredded flake form and uses them directly for foam core applications, avoiding the expensive chemical reprocessing needed to create high-quality polymers
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
This process significantly reduces production costs by utilizing high percentages of recycled polymers in the form of shredded flakes, enabling the production of cost-effective polymeric articles with enhanced reproducibility and homogeneity, while maintaining the quality of the foam core sandwich structure.
Implementation Method 1
heating the mould to a processing temperature, which is above the melting temperature of all of the first, second, and third polymeric materials
Implementation Method 2
above the melting temperature of all of the first, second, and third polymeric materials
Implementation Method 3
the blowing agent is a substance which is capable of producing a cellular structure in the second polymeric material upon heating above an activation temperature
Implementation Method 4
cooling the mould to or below a demoulding temperature
Data Source
AI summary
A process for producing a polymeric article is provided that includes: sequentially filling a female mould (11) with a first, second, and third batches, wherein the first and third batches include first and third polymeric materials (1p, 3p), and the second batch includes a second polymeric material (2p) and a blowing agent (2b), closing the thus filled cavity with a lid (12) to form a mould defining a closed cavity (10c) of constant volume in time, heating the mould (10) to a processing temperature, to melt the first, second, and third polymeric materials (1p-3p) and to expand the second polymer agent by activation of the blowing agent, cooling and removing the lid (12) to open the cavity and extracting the polymeric article. At least the second polymeric material (2p) includes at least 50 wt. % of recycled polymer in the form of shredded flakes.