UV-Permeable Multilayer Insert Tube for Pipe Renovation
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Solution Overview
Problem
Conventional multilayer films used for pipe renovation lack sufficient mechanical properties and UV permeability, leading to weak sealing seams and inability to withstand handling and inflation stresses during pipe renovation.
Innovation Solution
A multilayer film with a layer sequence of thermoplastic olefin homopolymer or copolymer as outer layers, adhesion promoter layers, and homo- and/or copolyamide inner layers, providing excellent mechanical extensibility and UV permeability, allowing for effective pipe renovation without prior conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional multilayer films are used for pipe renovation, then UV radiation permeability is achieved, but mechanical properties and sealing seam strength are insufficient
Solution Approach 1:
The patent applies composite materials by creating a multilayer film structure combining polyamide layers (for UV permeability and mechanical strength) with ionomer sealing layers (for strong sealing seams). This composite structure allows the film to simultaneously achieve UV radiation permeability for resin curing and sufficient mechanical strength for handling and sealing during pipe renovation operations.
2Illumination intensity
If polyamide layer is used for UV permeability, then resin curing is enabled, but mechanical extensibility and load resistance are insufficient
Solution Approach 1:
The patent combines polyamide layers with ionomer sealing layers to create a composite structure where the polyamide provides UV transmission for resin curing while the ionomer layers contribute mechanical strength and extensibility to withstand handling and inflation stresses during pipe renovation.
Solution Approach 2:
The patent applies local quality by assigning different functions to different layers: the polyamide layers are optimized for UV radiation transmission and mechanical flexibility, while the ionomer sealing layers are specifically designed for strong sealing and stress resistance at critical seam locations, allowing each layer to excel at its specific function.
3Ease of manufacture
If conventional films are used without conditioning, then processing is simpler, but mechanical properties are insufficient to withstand renovation loads
Solution Approach 1:
The patent applies parameter changes by carefully selecting and optimizing the chemical composition and physical properties of the polymer materials used in each layer, including molecular weight, crystallinity, and composition ratios, to achieve sufficient mechanical strength without requiring additional conditioning steps, thus maintaining processing simplicity while improving mechanical properties.
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 multilayer film exhibits a high barrier effect against resin drying, maintains mechanical integrity during pipe renovation, and allows for successful curing of reactive plastic resins, ensuring a stable pipe renovation process without premature resin hardening or film damage.
Implementation Method 1
a layer (a) based on at least one thermoplastic olefin homopolymer or copolymer as one of the outer layers... an inner layer (c) based on at least one homo- and/or copolyamide... wherein the thermoplastic olefin-Homo or copolymer of layer (a) has a VICAT softening temperature of at least 100 °C... at least partially permeable to UV radiation
Implementation Method 2
an adhesion promoter layer (b)... an adhesion promoter layer (d)... the polyamide layer is bonded to a fibrous fleece by heating
Implementation Method 3
the multilayer film according to the invention is characterized by a sufficient barrier effect against the drying out of the resin used for pipe renovation, and thus against the loss, i.e. migration, of monomers or remaining impregnating agent
Data Source
Figure 1
AI summary
The invention relates to a liquid-tight multi-layer film, preferably in the form of a tubular film, which is at least partially permeable to UV radiation, comprising a sequence of layers composed of a layer (a) on the basis of at least one thermoplastic olefin homopolymer or copolymer as one of the outside layers, an adhesion promoter layer (b), an interior layer (c) on the basis of at least one homopolyamide and/or copolyamide, an adhesion promoter layer (d), and a layer (e) on the basis of at least one homopolyamide and/or copolyamide as one of the outside layers, wherein the thermoplastic olefin homopolymer or copolymer of layer (a) has a VICAT softening temperature of at least 100°C. The invention further relates to the use of such a multi-layer film as an interior tube for an insert tube for refurbishing underground pipes, to such an insert tube, and to a pipe refurbishment system suitable for refurbishing underground pipes, preferably underground sewer pipes.