Polyamide Multilayer Film for Sewer Rehabilitation
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Solution Overview
Problem
Conventional multilayer films used in trenchless sewer rehabilitation lack mechanical robustness, particularly at low temperatures, and are not effective barriers against organic monomers and solvents, leading to issues like bursting, splicing, and environmental pollution.
Innovation Solution
A multilayer film with a polyamide layer and another polymer layer, partially transparent to UV radiation and organic volatile substances, offering a tensile modulus of elasticity between 1 to 250 MPa, ensuring high extensibility and abrasion resistance, even at temperatures below 0°C, while acting as a reliable barrier against escaping monomers and solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional multilayer films are used in trenchless sewer rehabilitation, then the process can be completed, but the films lack mechanical robustness at low temperatures leading to bursting and splicing
Solution Approach 1:
The patent employs a five-layer composite film structure combining different polymers (polyamide, polyethylene, polypropylene) with distinct functions. The polyamide layers provide mechanical strength and low-temperature flexibility, while polyethylene and polypropylene layers contribute to barrier properties and structural stability. This composite approach resolves the contradiction by integrating materials that individually address different requirements, achieving both mechanical robustness and low-temperature performance.
Solution Approach 2:
Different layers of the multilayer film are assigned specific local functions: the polyamide layers (1 and 5) are positioned to provide mechanical strength and flexibility where needed, while the intermediate layers (2-4) provide barrier and structural functions. This local differentiation of material properties within the composite structure allows the film to maintain overall mechanical robustness while specifically addressing low-temperature performance through the polyamide components.
2Object-affected harmful factors
If conventional multilayer films are used, then the structure is simple, but they are not effective barriers against organic monomers and solvents leading to environmental pollution
Solution Approach 1:
The patent uses a composite multilayer structure where specific polymer layers (particularly polyethylene and polypropylene layers) provide enhanced barrier properties against organic monomers and solvents. The combination of different polymers creates a multi-barrier system that is more effective than single-material films, preventing the escape of harmful substances into the environment while maintaining structural integrity.
Solution Approach 2:
The barrier function is locally optimized by positioning specific polymer layers (layers 2-4 consisting of polyethylene and polypropylene) between the inner and outer polyamide layers. These intermediate layers are specifically selected for their low permeability to organic substances, creating localized barrier zones that effectively block the passage of monomers and solvents without compromising the overall film structure.
3Ease of manufacture
If the film remains in the renovated sewer section, then cost is reduced and process is simplified, but the film must withstand long-term mechanical loads and abrasion
Solution Approach 1:
The patent employs a composite five-layer structure where the outer polyamide layers (1 and 5) provide superior abrasion resistance and mechanical durability for long-term service in the sewer environment. The intermediate layers provide structural support and barrier functions. This composite design enables the film to remain in the renovated sewer section long-term by distributing mechanical stresses across multiple layers with complementary properties, ensuring both process simplicity and long-term reliability.
Solution Approach 2:
The film structure is optimized for long-term durability by positioning the most abrasion-resistant polyamide layers on the outer surfaces (layers 1 and 5) where they directly contact the sewer environment. The intermediate layers (2-4) provide structural reinforcement and barrier functions. This local optimization of material placement ensures that the film can withstand long-term mechanical loads and abrasion while maintaining the simplified process of leaving the film in place.
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 provides enhanced mechanical properties, such as high extensibility and abrasion resistance, allowing it to remain in the renovated sewer section without bursting or splicing, and effectively prevents the escape of flammable mixtures, thus simplifying and cost-reducing the trenchless sewer rehabilitation process.
Implementation Method 1
the inner tube film is preferably permeable to UV light so that the resin of the tube lining structure can be cured efficiently from the inside of the sewer when it has been introduced into the sewer to be renovated by introducing UV light sources into the lumen of the inflated canal
Implementation Method 2
the outer tubular film is preferably impermeable to UV light in order to be a to prevent premature hardening of the resin, for example due to sunlight outside the sewer to be renovated
Implementation Method 3
a multilayer film which comprises at least one polyamide (PA) layer and at least one further layer made of another polymer material and is at least partially transparent to electromagnetic radiation in a wavelength range of 150 to 600 nm and to organic volatile substances with a Molecular mass of 20 to 300 gmol-1
Data Source
AI summary
The invention relates to a polymer multi-layered film with at least one polyamide layer and at least one additional layer made from another polymer material, said multi-layered film having high elasticity and good extensibility.