Fire-resistant bituminous cellulose cover plate and manufacturing method
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Solution Overview
Problem
Cellulose fiber boards impregnated with bitumen lack sufficient fire resistance to meet evolving safety standards, particularly the European standard EN 13501-5, due to instability in existing methods of applying expandable graphite coatings.
Innovation Solution
A process involving the deposition of a bonding primer followed by a dry application of a fire-resistant coating comprising expandable graphite, using methods like spraying in a fluidized bed or hopper, to ensure a homogeneous and effective fire-resistant layer on cellulose fiber boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bitumen-impregnated cellulose fiber boards are used for roofing, then they provide lightweight, strong, flexible, and inexpensive roofing material, but they have poor fire resistance that fails to meet safety standards
Solution Approach 1:
A bonding primer layer is introduced as an intermediary between the bitumen-impregnated cellulose fiber board and the expandable graphite fire-resistant coating. This primer ensures stable adhesion of the graphite coating to the board surface, preventing coating instability and ensuring the fire-resistant layer remains effectively attached during fire exposure.
Solution Approach 2:
The physical and chemical parameters of the board surface are modified by applying a bonding primer layer that changes the surface properties to enable better adhesion of the expandable graphite coating, transforming the surface from non-adhesive to adhesive for the fire-resistant material.
2Reliability
If expandable graphite coating is applied to improve fire resistance, then fire protection is enhanced, but the coating becomes unstable and fails to meet standard EN 13501-5
Solution Approach 1:
The bonding primer acts as a mediator between the board and expandable graphite coating, providing a stable intermediate layer that ensures the graphite coating adheres firmly and maintains its integrity during fire exposure, thereby achieving both fire resistance and coating stability required by EN 13501-5.
Solution Approach 2:
A composite structure is created consisting of the bitumen-impregnated cellulose fiber board, bonding primer layer, and expandable graphite coating. This multi-layer composite ensures both stable adhesion and effective fire resistance, meeting the stringent requirements of standard EN 13501-5.
3Reliability
If a fire-resistant coating is applied to the board, then fire protection is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The bonding primer is applied in advance as a preliminary step before applying the expandable graphite coating. This preliminary action prepares the surface to ensure stable adhesion, simplifying the overall manufacturing process by preventing coating instability issues that would require rework or additional complex steps.
Solution Approach 2:
The bonding primer serves as an intermediary layer that simplifies the manufacturing process by ensuring reliable adhesion of the expandable graphite coating, eliminating the need for complex surface treatment or additional bonding mechanisms.
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 significantly enhances the fire resistance of cellulose fiber boards, meeting the European standard EN 13501-5 by providing a stable and insulating graphite layer that delays or stops fire propagation and penetration, as demonstrated by positive results in fire resistance tests.
Implementation Method 1
Expandable graphite is an intumescent agent which, after exposure to fire, expands and creates an insulating barrier
Implementation Method 2
creates an insulating barrier that delays or stops fire propagation and penetration
Implementation Method 3
a bonding primer layer comprising a thermoplastic polymer is deposited on at least one of the main surfaces of the bitumen-impregnated cellulose fiber board
Implementation Method 4
a dry deposition, on the bonding primer layer, of a fire-resistant coating comprising expandable graphite
Implementation Method 5
using methods like spraying in a fluidized bed or hopper
Data Source
AI summary
The sheet has an adhesive primer layer on one of main surfaces of the sheet. A fireproof coating comprising expandable graphite is deposited on the adhesive primer layer by fluidized bed spray deposition or hopper deposition. A layer of paint is deposited on the fireproof coating. The expandable graphite has a trigger temperature ranging from 160 degree Celsius to 220 degree Celsius. Local dry matter basis weight of the expandable graphite is 80 grams per square meter in any point having a developed surface ranging from 1 to 2 square centimeters. An independent claim is also included for a method of manufacturing a bitumen-impregnated cellulose fiber sheet.