Shaped Nonwoven Web for Respiratory Filter Pressure Drop

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Solution Overview

Problem

Existing filtration elements for respiratory protection devices face challenges in balancing pressure drop, structural integrity, manufacturing complexity, and cost, particularly when incorporating sorbent particles, as traditional methods like resin bonding are expensive and reduce carbon activity.

Innovation Solution

A porous non-woven web with layers of thermoplastic elastomeric polymer fibers and active particles, featuring a three-dimensional deformation, which allows for lower pressure drop, better carbon retention, and simpler manufacturing, enabling the production of filter elements with enhanced performance and structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If resin bonding is used to incorporate sorbent particles, then structural integrity is improved, but processing cost increases and carbon activity is reduced

Engineering Contradiction:

Improvestructural integrityVSAvoidprocessing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent extracts the bonding function from resin and replaces it with mechanical entanglement of thermoplastic elastomeric fibers. The fibers are melted and bonded together through heat and pressure in a molding process, eliminating the need for separate resin bonding agents while maintaining structural integrity and preserving carbon activity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a disposable molding approach where the thermoplastic elastomeric fibers are directly molded into the final filter element shape in a single process step. This eliminates multiple processing steps and expensive resin bonding operations, reducing manufacturing cost while maintaining structural integrity through the molded fiber assembly.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Strength

If traditional filtration elements are used, then structural integrity is maintained, but pressure drop increases

Engineering Contradiction:

Improvestructural integrityVSAvoidpressure drop

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The patent creates local variations in fiber density and layer thickness to optimize both structural integrity and flow characteristics. The thermoplastic elastomeric fibers are arranged with varying densities across different regions of the filter element, providing adequate strength where needed while maintaining low pressure drop in high-flow regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite construction with multiple layers of thermoplastic elastomeric fibers containing different sorbent particles. The composite structure combines layers with different properties to achieve both structural integrity and low pressure drop, with some layers optimized for strength and others for flow efficiency.

Inventive Principle:

Principle #40Composite materials

3Strength

If complex shapes are manufactured using traditional methods, then structural integrity is achieved, but manufacturing complexity increases

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent performs preliminary shaping of the thermoplastic elastomeric fibers during the molding process itself. The fibers are fed into a mold and shaped into the final complex configuration in a single operation, eliminating the need for subsequent shaping or assembly operations and reducing manufacturing complexity while maintaining structural integrity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses changes in temperature and pressure parameters during molding to achieve complex shapes directly from the thermoplastic elastomeric fibers. By controlling the melting and bonding parameters, the process can form complex three-dimensional structures in a single step, simplifying manufacturing while ensuring structural integrity through proper parameter optimization.

Inventive Principle:

Principle #35Parameter changes

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 filter elements with reduced pressure drop, lower processing costs, and improved carbon activity retention, facilitating the production of complex shapes and multi-layer configurations that enhance filtration performance while maintaining structural integrity.

Implementation Method 1

heating and molding the layers into a generally cup shape with the deformation

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

heating and molding the layers into a generally cup shape with the deformation

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS20110240027A1Shaped layered particle-containing nonwoven web

Publication Date: 2011.10.06 3M INNOVATIVE PROPERTIES CO

AI summary

A filter element includes a porous non-woven web. The porous non-woven web includes a first layer with first thermoplastic elastomeric polymer fibers and first active particles disposed therein and a second layer including second thermoplastic elastomeric polymer fibers and second active particles disposed therein. The web possesses a three-dimensional deformation and the first layer is contiguous with the second layer across the deformation.