Aramid Nonwoven Carrier With Inorganic Refractory Layer
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Solution Overview
Problem
There is a need for a thin inorganic refractory layer that can be safely handled and processed into a multi-layer composite for use as a flame barrier component in thermal and acoustic blankets for aircraft structures, with existing solutions facing challenges in bond strength, handling, and processing efficiency.
Innovation Solution
A multilayered sheet comprising a paper carrier with an inorganic refractory layer, where the carrier is made of 70-90% aramid fibers and 10-30% polymeric binder, with specific tensile strength, density, and air permeability properties, and the refractory layer is deposited using an aqueous slurry and dried at controlled temperatures to achieve strong bonding and efficient processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thin inorganic refractory layer is used, then the flame barrier effectiveness is improved, but the handling safety and processing difficulty deteriorate
Solution Approach 1:
The patent applies this principle by using a thin paper carrier (0.025-0.175 mm) that provides flexibility and ease of handling while supporting the refractory layer. The paper carrier acts as a flexible substrate that enables the thin refractory coating to be handled safely and processed into multi-layer composites without compromising handling safety.
Solution Approach 2:
The patent applies this principle by creating a composite structure consisting of a paper carrier and an inorganic refractory layer coated on it. This composite material combines the handling advantages of paper with the flame barrier properties of the refractory layer, resolving the contradiction between thin refractory layer effectiveness and handling safety.
2Object-affected harmful factors
If the refractory layer is made thinner, then the flame barrier performance is improved, but the bond strength requirement becomes more critical
Solution Approach 1:
The patent applies this principle by optimizing the drying temperature parameter (80-110°C) to achieve the desired bond strength. By controlling the drying temperature, the patent ensures that the refractory layer bonds sufficiently to the paper carrier while maintaining the thin layer configuration for effective flame barrier performance.
Solution Approach 2:
The patent specifies bond strength requirements of at least 0.25 lb/in (preferably at least 0.8 lb/in) to ensure the thin refractory layer remains attached during processing. This strength parameter ensures that even though the layer is thin for optimal flame barrier performance, it maintains sufficient adhesion to the carrier.
3Stability of the object's composition
If the carrier is made with high aramid fiber content, then the thermal stability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies this principle by specifying a quantitative composition range for the paper carrier (70-90 wt% aramid fibers, 10-30 wt% polymeric binder). This parameter specification provides thermal stability while maintaining manufacturability, as the defined ranges allow for standard manufacturing processes rather than requiring complex or specialized production methods.
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 provides a robust and flexible composite with effective flame barrier properties, ensuring the refractory layer remains attached to the carrier during processing and use, and enhances the thermal and mechanical stability of the blanket.
Implementation Method 1
drying the layered sheet at a temperature of from 80 to 110 degrees C. until the residual moisture content in the refractory layer is no greater than 10 percent by weight
Implementation Method 2
the carrier (i) comprises from 70 to 90 weight percent of aramid fibers and from 10 to 30 weight percent of polymeric binder, (ii) is hydrophilic
Data Source
AI summary
This invention pertains to a layered sheet comprising an inherently flame resistant high strength fiber wet-laid nonwoven carrier having a first and second surface and an inorganic refractory layer adjacent to at least one surface of the carrier wherein the refractory layer has a dry area weight of from 15 to 50 gsm and the bond strength between the refractory layer and the surface of the paper is at least 0.25 lb/in, preferably at least 0.8 lb/in, wherein the carrier comprises from 70 to 90 weight percent of aramid fibers and from 10 to 30 weight percent of polymeric binder, is hydrophilic, has a thickness of from 0.025 to 0.175 mm and a density of from 0.25 to 1.1 g/cc.