Multi-Component Adhesive for Lignocellulosic Composites
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Solution Overview
Problem
The wood composites industry faces challenges in manufacturing pressed particulate wood composites, particularly oriented strand board (OSB), due to the need for high press temperatures and pre-drying of wood substrates, which increases energy consumption, VOC emissions, and risks of thermal damage and fires, while also requiring lower moisture content.
Innovation Solution
A multi-component adhesive system comprising a polyfunctional isocyanate, a hydrophilic organic polyol, and a transition metal organometallic catalyst, applied as separate streams without pre-mixing, allows for the production of lignocellulosic composites at lower press temperatures (300°F-400°F) without increasing residence time, enabling the use of higher moisture content substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high press temperatures (greater than 400 F) are used to achieve effective adhesive cure in reasonable time, then adhesive bonding quality is improved, but energy consumption increases and thermal damage risk increases
Solution Approach 1:
The patent changes the chemical parameters of the adhesive system by introducing a multi-component formulation with specific catalysts and co-adhesives that modify the curing kinetics, enabling effective bonding at lower temperatures (300-400 F range) without sacrificing bond quality
Solution Approach 2:
The patent uses intermediary substances including catalysts (such as organometallic compounds) and co-adhesives that facilitate the curing reaction at lower temperatures, acting as mediators between the isocyanate and hydroxyl groups to enable bonding without high thermal energy input
2Reliability
If high press temperatures (greater than 400 F) are used to achieve effective adhesive cure, then adhesive bonding quality is improved, but VOC emissions increase
Solution Approach 1:
The patent modifies the thermal parameters of the pressing process by enabling cure at lower temperatures through chemical formulation changes, thereby reducing the thermal energy available to drive VOC emissions from the wood substrate
3Reliability
If high press temperatures (greater than 400 F) are used to achieve effective adhesive cure, then adhesive bonding quality is improved, but thermal damage to composite boards increases
Solution Approach 1:
The patent changes the temperature parameter of the pressing process from high (greater than 400 F) to moderate (300-400 F) range by introducing catalysts and co-adhesives that accelerate the curing reaction kinetics, allowing effective bonding without excessive thermal exposure that causes damage
4Reliability
If pre-drying of furnish to 2-6% moisture content is performed to enable MDI adhesive use, then adhesive performance is improved, but energy consumption increases and pre-drying step complexity increases
Solution Approach 1:
The patent changes the moisture content parameter acceptance range by modifying the adhesive chemistry with hydrophilic co-adhesives and catalysts that maintain reactivity and bonding quality across a broader moisture range (4-16%), eliminating the need for energy-intensive pre-drying to achieve 2-6% moisture content
Solution Approach 2:
The patent extracts or removes the pre-drying step from the manufacturing process by developing an adhesive system that does not require low moisture content substrates, thereby eliminating the associated energy consumption and process complexity
5Use of energy by moving object
If lower press temperatures (less than 400 F) are used to reduce energy consumption, then energy efficiency is improved, but adhesive cure effectiveness decreases
Solution Approach 1:
The patent changes the kinetic parameters of the adhesive system by introducing catalysts (such as organometallic compounds) and reactive co-adhesives that accelerate the curing reaction rate, compensating for the lower thermal energy input and maintaining cure effectiveness at reduced temperatures
Solution Approach 2:
The patent uses catalysts and co-adhesives as intermediary substances that facilitate and accelerate the curing reaction at lower temperatures, enabling effective crosslinking without the need for high thermal energy input
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
This approach reduces energy consumption, minimizes VOC emissions, enhances product quality, and improves plant safety by enabling the production of high-quality composites at lower temperatures and higher moisture content, potentially eliminating the need for pre-drying and reducing the risk of thermal damage.
Implementation Method 1
The multi-component adhesive contains at least a polyfunctional isocyanate, a hydrophilic organic polyol, and a catalyst. The catalyst preferably comprises at least one transition metal organometallic compound
Implementation Method 2
The multi-component adhesive minimally comprises two mutually reactive components that are desirably applied to the lignocellulosic substrate as separate streams independently of each other
Data Source
AI summary
Adhesives, reaction systems, and processes for the production of lignocellulosic composites. The reaction system comprises a multi-component adhesive and a lignocellulosic substrate. The lignocelluosic substrate comprises a plurality of lignocellulosic adherends and is preferably a mass of wood particles. The multi- component adhesive comprises a multi-functional isocyanate, a hydrophilic polyahl, and an organotransition metal catalyst. The multi-component adhesive is characterized by being formulated into at least two mutually reactive chemical component streams. The process comprises the separate application of the mutually reactive chemical component streams of the multi-component adhesive to the lignocellulosic substrate, followed by forming and pressing the adhesive treated substrate under conditions appropriate for curing the adhesive and forming a lignocellulosic composite article. The adhesives, reaction systems, and processes are particularly well suited for the production of oriented strand board (OSB).