Multilayer PVC Pipe with Expanded Recycled Middle Layer
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Solution Overview
Problem
Existing multilayer pipes do not effectively utilize micronized recycled PVC, leading to inefficiencies in processing, higher material costs, and environmental impact, as they are difficult to reprocess due to varying compositions from different applications.
Innovation Solution
The development of micronized recycled PVC multilayer pipes with three layers, where two are densely compact and one is expanded, using different compositions for each layer, incorporating a blowing agent to achieve desired density values, and processed via extrusion to reduce virgin PVC usage and enhance thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If micronized recycled PVC is used in the middle expanded layer, then the weight of pipes is reduced and raw material costs are lowered, but the processing difficulty increases due to varying compositions from different applications
Solution Approach 1:
The pipe is divided into three distinct layers with different functions: outer compact layer for protection, middle expanded layer with micronized recycled PVC for weight reduction and cost savings, and inner compact layer for structural integrity. This segmentation allows each layer to be optimized independently, making the processing of recycled materials more manageable.
Solution Approach 2:
Different regions of the pipe have different material compositions and densities tailored to their specific functions. The middle layer uses micronized recycled PVC with lower density (0.55-0.9 g/ccm) for weight reduction, while outer and inner layers use denser compact materials for structural requirements, allowing localized optimization of properties.
2Object-affected harmful factors
If virgin PVC is completely substituted with micronized recycled PVC, then environmental impact is reduced and raw material costs are lowered, but the technical characteristics and processing performance deteriorate
Solution Approach 1:
The density of the middle layer is controlled within a specific range (0.55-0.9 g/ccm) by adjusting the proportion of micronized recycled PVC and expansion agents. This parameter optimization ensures that the recycled material provides both environmental benefits and adequate technical performance for non-structural applications.
Solution Approach 2:
The pipe uses a composite structure combining micronized recycled PVC with expansion agents and additives in the middle layer, while maintaining virgin or high-quality PVC in outer and inner layers. This composite approach balances environmental sustainability with technical reliability.
3Weight of stationary object
If the middle layer is expanded with lower density, then the weight of pipes is reduced, but the structural strength may be compromised
Solution Approach 1:
The pipe structure is segmented into three layers where the expanded middle layer provides weight reduction while the compact outer and inner layers provide the necessary structural strength and protection, allowing the weakened middle layer to be compensated by the stronger boundary layers.
Solution Approach 2:
Strength-critical regions (outer and inner surfaces) are reinforced with compact, high-density materials, while the non-critical middle region uses low-density expanded material for weight reduction, optimizing the strength-to-weight ratio locally throughout the pipe structure.
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 solution results in pipes with improved technical and functional characteristics, reduced weight, lower costs, and a positive environmental impact, making them suitable for a wider range of applications by fully substituting virgin PVC with micronized recycled PVC.
Implementation Method 1
incorporating a blowing agent to achieve desired density values
Data Source
Figure 1.1
AI summary
The invention relates to micronized recycled PVC multilayer pipes obtained by the extrusion process which are formed of three layers, two of which are densely compact and are placed one on the inside, having a virgin PVC K 64-64 or micronized recycled PVC, the other on the outside of the pipe, having a virgin K-64-68 PVC composition, and a middle layer of lower density, expanded and having a micronized recycled PVC composition, these pipes are used in sewage installations, both inside and outside the buildings, and the invention also relates to the process of obtaining these pipes by extrusion, using manufacturing compositions with different compositions, a composition for the compact layer the density of which ranges between 1.45-1.9 g/cm3 and the other for the expanded layer whose density value is between 0.55-0.9 g/cm3. The compositions are made by means of metering devices for mixing the components, the mixed mixture of the proportions is introduced into the mixer, it is mixed up to a temperature of 110-130°C and then cooled to a temperature of 40-50°C in a cooler. Pipes may have different characteristics necessary and useful for their use, which, for example, but not limited to, -by the value of the flow - by the outer diameter and the annular rigidity - by the thickness of the walls. The admixture of PVC mass gives a thermal stability of PVC (virgin or micronized recycled), better machining, a reduction in pipe weight, a lower price due to reduced cost of raw material based on micronized recycled PVC and a positive impact on the environment by reintroducing micronized recycled PVC into compositions.