Reactive Binder Wood Composite Manufacturing
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Solution Overview
Problem
Conventional wood-plastic composite materials face issues with inadequate bonding between vegetable fibers and plastic, leading to trapped air in pores, reduced strength, and poor fire behavior due to high plastic viscosity during the manufacturing process.
Innovation Solution
A method involving the use of a reactive binder with reactive components or prepolymers, which is preheated with vegetable fibers in an extruder, forming a homogenous composite mixture that is then pressed into a curing mold to maintain the reaction temperature, allowing the binder to penetrate into the fibers' pores and displace air, resulting in improved bonding and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thermoplastic resin is used as a binder and the mixture is heated and extruded, then the material can be formed into solid shapes, but the plastic viscosity becomes too high to penetrate into the pores of the vegetable fibres, resulting in inadequate bonding and trapped air
Solution Approach 1:
The patent changes the fundamental parameter of the binder from thermoplastic to reactive binder, which undergoes chemical transformation during processing. This allows the binder to maintain low viscosity during extrusion and then cure to form strong bonds, resolving the contradiction between temperature and bonding strength
Solution Approach 2:
The reactive binder acts as an intermediary that first mixes easily with fibres at low viscosity, then transforms through chemical reaction to create strong adhesion. This intermediary substance enables both good distribution and strong bonding without requiring high temperatures
2Strength
If air remains trapped in the pores of the vegetable fibres, then the bonding between fibres and plastic is reduced, but eliminating the air requires the plastic to penetrate into the pores which is prevented by high viscosity
Solution Approach 1:
The reactive binder's viscosity parameter changes during the process - low during mixing to allow pore penetration and air displacement, then increases through curing to provide structural strength. This dynamic parameter change eliminates trapped air while maintaining bonding strength
Solution Approach 2:
The binder penetrates into the fibre pores and displaces air before the final curing takes place. This preliminary penetration action ensures complete fibre impregnation and eliminates air pockets that would otherwise weaken the composite
3Ease of manufacture
If conventional thermoplastic granulate is physically mixed with vegetable fibres, then the manufacturing process is simple, but the resulting material has poor fire behaviour and inadequate durability
Solution Approach 1:
The reactive binder serves as a chemical intermediary that creates strong covalent bonds with the vegetable fibres, forming a integrated composite structure. This chemical bonding mechanism provides superior fire resistance and durability compared to physical mixing, while maintaining ease of manufacture through the extrusion-curing process
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 method produces a wood composite material with enhanced shape retention, heat resistance, strength, and fire safety, as the reactive binder effectively binds with fibers, reducing deformation and making the material nearly non-combustible.
Implementation Method 1
the reactive binder enters the pores of the wood fibre and expels the air within the pores
Implementation Method 2
the reaction product of the reactive binder optimally binds with the vegetable fibres
Implementation Method 3
the extrusion device is used to preheat a mixture of vegetable fibres with a reactive binder
Implementation Method 4
The composite mixture thus formed, which is still deformable at the extrusion discharge and which has started reacting and polymerizing, is subsequently maintained at the reaction temperature in the curing mould, thereby maintaining the reaction
Data Source
Figure 1
Figure 2
AI summary
Method for manufacturing a wood composite, comprising the steps of providing an reactive composite mixture (4) by mixing a reactive binder and vegetable fibres; supplying the reactive composite mixture to an extruder (5), discharging of the composite mixture from the extrusion device via an extrusion discharge (6) to a curing mould (8); filling the pores of the vegetable fibres with the reactive binder while simultaneously expensing the air from the pores at extrusion process conditions; reacting of the reactive binder around the vegetable fibres and in the pores of the vegetable fibres into a wood composite at the temperature of the extrusion process conditions.