Foamed Pipe Manufacturing Using Combined Blowing Agents
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Solution Overview
Problem
Existing methods for producing cable guide pipes with foamed intermediate layers result in inhomogeneous structures, leading to mechanical weaknesses and increased manufacturing costs, which are not suitable for applications requiring high mechanical properties and pressure resistance.
Innovation Solution
A method using a combination of chemical and physical blowing agents, where thermally unstable solids and expandable microspheres are incorporated into the plastic starting material to create a homogeneous cellular structure, avoiding the formation of clusters and enhancing mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If pressurized gas is introduced into the mold to produce the foamed intermediate layer, then thermal insulation is improved, but the cellular structure becomes inhomogeneous leading to mechanical weaknesses
Solution Approach 1:
The patent changes the state of the blowing agent from gaseous (pressurized gas) to solid (thermally unstable solids and expandable microspheres). This parameter change allows the blowing agent to be uniformly distributed in the plasticized plastic material, creating a homogeneous cellular structure that maintains both thermal insulation and mechanical strength.
Solution Approach 2:
The patent uses expandable microspheres as a physical blowing agent that copies the desired cellular structure uniformly throughout the foam. These microspheres expand during foaming to create consistent cell sizes and distributions, avoiding the cluster formation that occurs with pressurized gas methods.
2Quantity of substance
If pressurized gas is used to create the foamed intermediate layer, then material savings are achieved, but the cellular structure forms clusters causing mechanical weaknesses
Solution Approach 1:
The patent changes the physical state of the blowing agent from gas to solid particles (thermally unstable solids and expandable microspheres). This allows uniform distribution throughout the plastic material, preventing cluster formation while maintaining material efficiency through the foam structure.
Solution Approach 2:
The blowing agents (thermally unstable solids and expandable microspheres) are pre-mixed with the plastic starting material before molding. This preliminary uniform distribution ensures homogeneous cellular structure formation during the foaming process, preventing cluster formation while achieving material savings through the lightweight foam structure.
3Ease of manufacture
If a foamed intermediate layer is produced with pressurized gas, then production costs are reduced, but mechanical properties deteriorate
Solution Approach 1:
The patent changes the blowing agent state from gaseous to solid (thermally unstable solids and expandable microspheres), which enables uniform cellular structure formation. This improves mechanical properties while maintaining the cost advantages of foam structures through material savings and simplified manufacturing.
Solution Approach 2:
The patent uses a composite approach by combining thermally unstable solids and expandable microspheres as blowing agents within the plastic matrix. This composite system achieves both cost effectiveness through foam structure and improved mechanical properties through homogeneous cell distribution.
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 achieves a uniform cellular structure with improved mechanical properties, comparable to solid pipes, while reducing production costs and simplifying handling, with significant material savings and reduced weight, maintaining excellent thermal insulation.
Implementation Method 1
the plastic starting material for producing the foamed intermediate layer or the granules to be foamed is equipped from the outset with thermally unstable solids as blowing agents
Implementation Method 2
the physical blowing agent is expandable microspheres
Implementation Method 3
the foamed intermediate layer is largely implemented for reasons of thermal insulation
Data Source
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AI summary
The present invention relates to a method for manufacturing a pipe, particularly a cable conduit, from a thermoplastic synthetic material. Said pipe is equipped with at least one triple-layered, single-material structure consisting of a pipe inner wall (4), a foamed intermediate layer (7) and a pipe outer wall (5). According to the invention, said intermediate layer (7) is foamed by the combined action of at least one chemical propellant and one physical propellant.