Mixed Waste Plastic Composite Molding at Lower Processing Temperatures
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Solution Overview
Problem
Mixed plastic waste, which is a mixture of different plastic types, is challenging to recycle due to economic and technical reasons, often remaining as waste at recycling plants and not being reused effectively.
Innovation Solution
A method involving mixing quartz sand with mixed waste plastic, preferably in a 30-60%:40-70% ratio, and processing it through an extruder at controlled temperatures (200-250°C) to create a mixture that is then shaped and cooled, optionally with added pigments, to form products like construction materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If mixed waste plastic is processed at high temperatures (260-300°C) as in prior art, then the plastic can be melted and formed, but the plastic degrades and burns
Solution Approach 1:
The patent changes the temperature parameter from the conventional 260-300°C range to a lower 180-220°C range, which prevents plastic degradation and burning while still enabling the plastic to be processed and formed into construction materials
Solution Approach 2:
The patent creates a composite material by mixing ground mixed waste plastic with ground natural stone (80-95% stone, 5-20% plastic by weight), which allows processing at lower temperatures while maintaining structural integrity and preventing plastic degradation
2Loss of substance
If mixed waste plastic is used directly in construction materials, then waste reduction is achieved, but the mechanical properties are insufficient
Solution Approach 1:
The patent develops a composite construction material combining ground natural stone (80-95%) with ground mixed waste plastic (5-20%), where the stone provides mechanical strength and the plastic provides binding properties, achieving both waste utilization and adequate mechanical properties
Solution Approach 2:
The patent assigns different functional roles to different components: the natural stone provides structural strength and rigidity, while the plastic component provides binding and flexibility, with each material contributing its optimal properties to the composite
3Manufacturing precision
If mixed waste plastic is separated into individual plastic types, then recycling quality improves, but economic feasibility deteriorates
Solution Approach 1:
The patent treats mixed waste plastic as a homogeneous material suitable for direct use in construction applications, eliminating the need for complex separation processes while maintaining adequate material quality for non-structural construction purposes
Solution Approach 2:
The patent creates construction materials (paving stones, bricks, tiles) from mixed plastic waste that are designed for durable outdoor use, providing an economically viable application for plastic mixes that would be too costly to separate
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 method effectively processes mixed waste plastic into usable construction materials, reducing waste and avoiding the degradation of plastics at higher temperatures, while ensuring mechanical and aesthetic properties.
Implementation Method 1
the pipe is heated to a temperature between 200 and 250 °C to allow the plastic to melt and bind with the sand
Implementation Method 2
to allow the plastic to melt and bind with the sand
Implementation Method 3
a cooling system arranged to cool the mould during formation of the product
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention belongs to the field of recycling plastic waste, particularly mixed plastic, recycling of which is very challenging. The invention relates to a device and a method for processing mixed waste plastic (MWP) and products made from mixed waste plastic. The mixed waste plastic comprises at least two of the following plastics: acrylonitrile butadiene styrene (ABS), ABS and glass fibre composite (ABS GF), polycarbonate (PC), polycarbonate and glass fibre composite (PC GF), PC-ABS composite, polyamide (PA), polybutylene terephthalate (PBT), and quartz sand (QS) with granulation up to 3 mm mixed in a selected ratio, which is from 30% : 70% to 60% : 40%. The method comprises the following steps: a) mixing MWP and QS, b) leading the prepared mixture to the extruder comprising a shaft with blades arranged for mixing and moving the material along the extruder, wherein the extruder is heated to a temperature between 200 and 250 °C, c) extruding the material from the extruder to a heated container, heated so that the temperature of the material inside it is between 210 and 240 °C, d) leading the material into a mould inside a press arranged to compress the mould, which presses the material into the desired shape, wherein said mould is cooled so that the product is cooled to a temperature between 60 and 90 °C and hardens.