Multi-layer, biodegradable composites for air filtration
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Solution Overview
Problem
Existing air filters face challenges in achieving low pressure drop, high dust holding capacity, and sufficient web strength while using sustainable bio-based materials, which are often more expensive and require reduced material usage.
Innovation Solution
A multi-layer composite air filter design featuring a first nonwoven web layer with multicomponent aliphatic polyester fibers, such as PLA and PBS, and a second layer with monocomponent PLA fibers, arranged to provide enhanced dust holding capacity and low pressure drop, eliminating the need for additional support layers and non-biodegradable stabilizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sustainable bio-based materials are used in air filters, then environmental sustainability is improved, but material cost increases
Solution Approach 1:
The filter media is divided into multiple functional layers, each made from biodegradable materials with specific properties. The segmentation allows optimization of each layer for its specific function while maintaining overall sustainability, reducing the need for expensive non-biodegradable stabilizers in the entire structure.
Solution Approach 2:
The invention uses composite structures combining different biodegradable materials (cellulose, polyester, polyamide, polyacrylonitrile, or polyvinylidene fluoride) to achieve the required performance characteristics. This composite approach allows sustainable materials to meet performance requirements without needing costly additives or stabilizers.
2Duration of action of stationary object
If filter media with high dust holding capacity is designed, then filter service life is improved, but pressure drop increases
Solution Approach 1:
The invention transitions from a single-layer to a multi-layer structure, adding the dimension of layer differentiation. Each layer is optimized for specific functions: the first layer captures larger particles, the second layer captures finer particles, and the third layer provides support. This dimensional change allows high dust holding capacity without excessive pressure drop.
Solution Approach 2:
Different layers are assigned different local qualities and functions. The first and second layers have high porosity and low density for particle capture with minimal pressure drop, while the third layer has higher strength for structural support. This local optimization resolves the contradiction between dust holding capacity and pressure drop.
3Device complexity
If web strength is increased to eliminate support layers, then manufacturing complexity is reduced, but material usage increases
Solution Approach 1:
The invention merges multiple functions into the filter media itself: particle filtration, structural support, and self-supporting capability are all integrated into the multi-layer biodegradable structure. This eliminates the need for separate support layers and reduces overall material usage while maintaining sufficient web strength.
Solution Approach 2:
The filter media is designed to be self-supporting through its multi-layer structure, eliminating the need for external support layers. The third layer provides the necessary tensile strength for the entire structure to stand on its own, reducing manufacturing complexity and material usage.
Data Source
AI summary
The present disclosure relates to multi-layer composite articles including at least two nonwoven web layers. Each or the layers may be a spunbonded web, and each may include biodegradable materials. The multi-layered composites of the present disclosure are particularly well suited for air filtration, as they can combine a high dust holding capacity with sufficient strength, dimensional stability, and a relatively low pressure drop.