Polyester Nonwoven Laminate for Structural Underbody Shields
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Solution Overview
Problem
Existing nonwoven laminates for underbody shield applications face challenges such as high costs, dimensional instability, poor mechanical stability, and difficulties in recycling due to the use of polyolefins and needled structures, which affect their performance and uniformity.
Innovation Solution
A nonwoven laminate composed of multicomponent and monocomponent staple fibers, bonded by melt-bonding, featuring a needled nonwoven layer with a high basis weight and layers of polyester and copolyester fibers, which provides high mechanical stability, low heat-shrinking properties, and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polypropylene layer is used at the interface between nonwoven fabric layers, then bonding between layers is achieved, but heat resistance and non-flammability are reduced due to low melting point
Solution Approach 1:
The patent removes the polypropylene layer from the composite structure, eliminating the material with low heat resistance and low melting point. This extraction resolves the contradiction by eliminating the source of the problem while maintaining bonding through alternative means (direct bonding of polyester layers or use of polyester-based adhesive layers).
Solution Approach 2:
The patent changes the material composition parameter by replacing polypropylene with polyester or copolyester layers. This parameter change increases the melting point and heat resistance of the composite while maintaining the bonding function through thermoplastic properties of the polyester materials.
2Strength
If combination of polyester and polypropylene is used, then mechanical properties are improved, but recyclability becomes difficult
Solution Approach 1:
The patent applies homogeneity by using polyester and copolyester materials throughout all layers of the composite, eliminating the heterogeneity caused by mixing different polymer types. This single-polymer-system approach maintains mechanical properties while enabling straightforward recycling processes.
3Stability of the object's composition
If spunbond nonwoven layers are used, then dimensional stability is achieved, but production cost increases significantly
Solution Approach 1:
The patent changes the fiber arrangement parameter by using heat-set staple fiber nonwovens instead of spunbond construction. The heat-setting process applies thermal treatment to stabilize the staple fiber structure, achieving dimensional stability comparable to spunbond but at lower production cost through simpler manufacturing processes.
4Strength
If needling is used to bond layers, then mechanical bonding is achieved, but layer structure uniformity deteriorates due to fiber penetration
Solution Approach 1:
The patent replaces the mechanical needling system with a thermal bonding system. Instead of using physical needles to penetrate and bond layers mechanically, the invention uses heat and pressure to melt thermoplastic fibers at bonding points, creating uniform bonds without mechanical fiber penetration and distortion.
5Strength
If reinforcing fibres and lofting agent are added to core layer, then mechanical stability is improved, but processability is reduced
Solution Approach 1:
The patent optimizes the basis weight parameter of the heat-set staple fiber nonwoven core layer to provide sufficient mechanical stability without adding reinforcing fibers. This parameter optimization maintains processability by avoiding the introduction of difficult-to-process materials while achieving the required mechanical performance through proper fiber arrangement and thermal setting.
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 solution results in a laminate with enhanced mechanical stability, low heat-shrinking, high acoustic absorption, and cost-effectiveness, suitable for applications requiring light weight and high stability, while being easily recyclable.
Implementation Method 1
The copolyester component has a melting point of 140° C. to 220° C. and acts as a binder which melts and bonds the fibres together.
Implementation Method 2
high bend strength, tensile strength, tear strength, hydrophobic properties, acoustic absorption, dimensional stability, uniformity, heat resistance and non-flammability
Data Source
AI summary
A nonwoven laminate, including a nonwoven layer including multicomponent staple fibres and a needled nonwoven layer including monocomponent staple fibres and multicomponent staple fibers, wherein the layers are bonded to each other by melt-bonding, and not by needling. The multicomponent staple fibers include a polyester component and a copolyester component and the monocomponent staple fibers in the needled nonwoven layer are polyester fibers. All fibres of the nonwoven laminate are polyester and/or copolyester fibers, and the needled nonwoven layer has a basis weight of 500 to 2000 g/m2, determined according to DIN EN 29073-1:1992-08. The nonwoven laminate has a bending force of at least 6 N, determined according to ISO 178:2019 for 2 mm deflection.