Hydrochar Building Boards With Low-Adhesive Flame Retardancy
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Solution Overview
Problem
Existing building materials, particularly those made from lignocellulosic biomass, face challenges in achieving high structural strength, recyclability, and effective flame retardancy while minimizing environmental impact, often relying on harmful additives that complicate recycling and fire safety.
Innovation Solution
A method involving the conversion of lignocellulosic biomass into hydrochar with a low O/C molar ratio, combined with a minimal amount of adhesive, and subjected to pressure and temperature to produce boards with enhanced mechanical strength and flame retardancy, enabling recyclability and circular economy integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flame retardants (halogen- or phosphorus-based) are added to lignocellulosic biomass materials, then flame retardancy is improved, but environmental impact increases and recyclability is compromised
Solution Approach 1:
The patent converts the inherent combustibility of lignocellulosic biomass from a harmful property into a beneficial flame-retardant characteristic through controlled thermal treatment. The biomass is heated to 200-400°C in a controlled atmosphere to form a carbonized layer that acts as a protective barrier, transforming the material's natural weakness into its primary fire safety mechanism without requiring harmful chemical additives
Solution Approach 2:
The invention extracts and removes harmful chemical additives (halogen- and phosphorus-based flame retardants) from the material composition entirely. Instead, it relies on the physically treated lignocellulosic biomass itself to provide flame retardancy through its carbonized structure, eliminating the need for toxic substances while maintaining fire safety performance
2Strength
If high percentage of adhesive (at least 25% phenolic compounds) is incorporated to achieve acceptable mechanical strength, then structural strength is improved, but recyclability is compromised and harmful volatile compounds are released
Solution Approach 1:
The patent fundamentally changes the adhesive content parameter from conventional levels (25% or higher phenolic compounds) to a minimal amount (1-20% by weight of total dry weight). This parameter change is made possible by the preliminary thermal treatment of the biomass, which creates a carbonized structure that requires far less binding agent to achieve adequate mechanical strength while maintaining recyclability
Solution Approach 2:
The invention uses a minimal amount of adhesive as a temporary binding agent during manufacturing that does not permanently compromise the material's recyclability. The low adhesive content (1-20%) allows the board to be disassembled and recycled at end of life, treating the adhesive as a short-term structural helper rather than a permanent bond
3Ease of manufacture
If hydrochar with high O/C molar ratio (0.3 or higher) is used in the process, then the material can be obtained more easily, but the mechanical strength of the resulting material is insufficient
Solution Approach 1:
The patent applies preliminary thermal treatment to the lignocellulosic biomass before board formation to reduce its O/C molar ratio from 0.3 or higher to below 0.2. This preliminary carbonization action transforms the biomass into a low-O/C hydrochar that provides both structural integrity and flame retardancy, enabling the use of minimal adhesive while achieving high mechanical strength
Solution Approach 2:
The invention changes the critical O/C molar ratio parameter of the hydrochar from 0.3 or higher to below 0.2 through controlled thermal treatment. This parameter transformation is essential for achieving both adequate mechanical strength and flame retardancy, allowing the material to form durable boards with minimal adhesive content
4Duration of action of stationary object
If lignocellulosic biomass is transformed into durable building materials using conventional methods, then material durability is improved, but flame retardancy is compromised and environmental impact increases
Solution Approach 1:
The patent merges multiple functions into the single lignocellulosic biomass material: structural durability, flame retardancy, and environmental sustainability. Through controlled thermal treatment, the biomass simultaneously develops the mechanical strength needed for durable building materials and the carbonized structure required for fire resistance, eliminating the need for separate flame-retardant additives that would compromise recyclability
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 resulting materials exhibit excellent fire performance with low heat and smoke release rates, maintaining structural integrity and recyclability, aligning with sustainability goals.
Implementation Method 1
applying a temperature between 100 and 180°C and a pressure of at least 5 MPa to the mould
Implementation Method 2
applying a temperature between 100 and 180°C and a pressure of at least 5 MPa to the mould
Implementation Method 3
adding to the solid a total amount of adhesive between 1% and 20% by weight of the total dry weight of the carbonaceous solid
Data Source
Figure 1~2B
Figure 3~4
AI summary
The present invention relates to the production of recyclable building materials from renewable sources. In particular, a method is described for preparing building materials from carbonaceous solids with an oxygen to carbon molar ratio of less than 0.2 and adhesive. Likewise, flame-retardant, recyclable and reusable building materials manufactured according to the described method are described.