Lignocellulosic Board Adhesive Using Sunflower Meal and pH Control
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Solution Overview
Problem
Existing processes for manufacturing multi-layer lignocellulosic articles, such as particleboards, face issues with strong odor and eye irritation due to urea in soy flour-based adhesives, leading to potential strength reduction and technical constraints in mixing wood chips/particles with fibers, as well as challenges in recycling MDF for OSB and particleboard production.
Innovation Solution
A two-part adhesive composition using ground sunflower or rapeseed meal instead of soy flour, with a solid part and a liquid part containing an amine-based azetidinium-functional cross-linker, where the pH of the liquid parts for the core and surface layers differ, allowing for reduced water addition and improved mechanical properties without compromising the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If soy flour-based adhesive with urea is used, then bonding strength is improved, but strong odor and eye irritation occur due to urease activity
Solution Approach 1:
The invention extracts and removes the harmful urease enzyme from the adhesive system by replacing soy flour with sunflower or rapeseed meal, which do not contain active urease. This eliminates ammonia release while maintaining the bonding functionality through alternative protein sources and cross-linking mechanisms.
Solution Approach 2:
The invention changes the chemical composition parameters of the adhesive by substituting the protein source (from soy to sunflower/rapeseed meal) and adjusting pH levels. This parameter change eliminates urease activity while preserving adhesive performance through controlled cross-linking reactions.
2Object-affected harmful factors
If heat treatment is applied to denature urease, then odor and eye irritation are reduced, but manufacturing complexity and energy consumption increase
Solution Approach 1:
The invention performs preliminary action by selecting raw materials (sunflower or rapeseed meal) that inherently lack active urease enzyme, eliminating the need for subsequent heat treatment or denaturation steps. This preventive approach simplifies the manufacturing process while achieving the desired reduction in harmful effects.
3Strength
If different pH adhesive compositions are used for core and surface layers, then mechanical properties and water resistance are improved, but adhesive composition complexity increases
Solution Approach 1:
The invention applies local quality by using different pH optimized adhesive compositions for specific layers (core vs. surface). The core layer receives one pH formulation optimized for its conditions, while surface layers receive a different pH formulation optimized for their exposure conditions, thereby improving overall performance through localized optimization.
4Strength
If soy flour is used as adhesive, then bonding is achieved, but recycling MDF for OSB and particleboard production becomes problematic
Solution Approach 1:
The invention facilitates discarding and recovering by using adhesives based on sunflower or rapeseed meal that allow for easier separation and recycling of wood fibers. These alternative protein-based adhesives enable the recovered MDF to be reused in OSB and particleboard production, creating a circular economy approach to wood composite manufacturing.
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 use of ground sunflower or rapeseed meal-based adhesives eliminates urease activity, reduces water usage, and enhances mechanical properties, internal bonding, water resistance, and surface soundness of the lignocellulosic boards, particularly at shorter press factors, while avoiding the issues associated with soy flour adhesives.
Implementation Method 1
a liquid part comprising a cross-linker, in particular an amine-based azetidinium-functional cross-linker
Implementation Method 2
curing the adhesive compositions impregnating the lignocellulosic material
Data Source
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AI summary
The present invention relates to a process for preparing a multi-layer lignocellulosic article comprising a core and two surface layers, wherein this process comprises the use of a two-part adhesive composition comprising a solid part comprising a ground sunflower or rapeseed meal and a liquid part comprising a cross-linker and wherein the pH of the liquid part used to resinate the lignocellulosic material forming the core layer is superior to the pH of the liquid part used to resinate the lignocellulosic material forming the surface layer.