Air Filter Medium With Interlaminar Heat-Expandable Particles
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Solution Overview
Problem
Conventional air filter media face challenges in achieving excellent flame retardancy while maintaining low pressure loss, as existing flame retardants require high amounts, leading to reduced air permeability and potential insufficient flame retardancy due to the flammability of binders.
Innovation Solution
Incorporating heat-expandable particles, such as expandable graphite, into the interlaminar spaces between fibrous sheets, which provide excellent flame retardancy even at low concentrations, reducing the need for large binder amounts and preserving air permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphorus-compound or inorganic flame retardants are incorporated into the fabric in large amounts, then flame retardancy is improved, but air permeability is reduced and pressure loss increases
Solution Approach 1:
The patent extracts the flame retardant function from the fabric structure itself and places it in separate particles (heat-expandable graphite and/or expandable perlite) that are disposed in the interlaminar spaces. This allows the flame retardant effect to be achieved without incorporating flame retardants directly into the fabric, thereby maintaining air permeability while providing flame retardancy.
Solution Approach 2:
The patent uses heat-expandable particles as intermediary substances that provide flame retardancy without directly affecting the fabric's air permeability. These particles are disposed in the interlaminar spaces and act as a mediator between the fabric layers, providing the desired flame retardant effect while minimizing impact on airflow.
2Reliability
If large amounts of binder are incorporated to adhere flame retardant to fabric, then flame retardancy is improved, but the flammability of binder may reduce overall flame retardancy and air permeability is reduced
Solution Approach 1:
The patent extracts the flame retardant function from the binder-flame retardant combination and implements it through heat-expandable particles disposed in interlaminar spaces. This eliminates the need for large amounts of binder to hold flame retardants, as the particles themselves provide the flame retardant effect when dispersed in the spaces between fabric layers.
Solution Approach 2:
The patent applies flame retardant functionality locally in the interlaminar spaces rather than throughout the entire fabric structure. By disposing heat-expandable particles specifically in the spaces between fabric layers, the flame retardant effect is concentrated where needed without affecting the overall air permeability of the fabric.
3Reliability
If flame retardants are incorporated into fabric, then flame retardancy is improved, but the amount of binder required increases leading to reduced air permeability
Solution Approach 1:
The patent extracts the flame retardant function from the fabric-binder system and implements it through separate heat-expandable particles disposed in interlaminar spaces. This eliminates the need for binder to incorporate flame retardants into the fabric, as the particles provide the flame retardant effect independently when placed in the spaces between fabric layers.
Solution Approach 2:
The heat-expandable particles act as intermediary substances that provide flame retardancy without requiring binder for incorporation. These particles are disposed in the interlaminar spaces and provide the flame retardant function independently, reducing or eliminating the need for binder while maintaining air permeability.
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 air filter medium exhibits enhanced flame retardancy with low pressure loss, as the heat-expandable particles form a carbonized wall upon burning, effectively isolating the burned area from the unburned area, while minimizing the use of binder and maintaining air permeability.
Implementation Method 1
heat-expandable particles, such as expandable graphite... the heat-expandable particles form a carbonized wall upon burning
Data Source
Figure 1~2
AI summary
An object of the present invention is to provide an air filter medium which includes heat-expandable particles that, even when contained in a small amount, impart excellent flame retardancy to the air filter medium and which has excellent flame retardancy and a low pressure loss. The present invention provides an air filter medium including: a plurality of stacked fibrous sheets; and heat-expandable particles and a binder disposed in at least one of interlaminar spaces between adjacent layers of the fibrous sheets.