Non-Urea Diluent Adhesive for Lignocellulosic Substrates
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Solution Overview
Problem
Conventional wood adhesives for particleboard, MDF, and OSB require lower viscosity systems, but diluting with water can cause steam blows or long press times, and urea is commonly used as a non-volatile denaturant, though a urea-free alternative is desirable.
Innovation Solution
A non-urea diluent, such as glycerol or sucrose, is used in combination with a formaldehyde-free crosslinker like polyamidoamine-epichlorohydrin resin to create a lower viscosity adhesive system for bonding lignocellulosic substrates, maintaining adhesive properties while reducing formulation viscosities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If water is used to dilute the adhesive to lower viscosity, then the adhesive viscosity decreases, but steam blows occur in the press or long press times are required to remove excess water
Solution Approach 1:
The patent changes the chemical composition parameter of the adhesive system by replacing water with non-volatile diluents (glycerol, sucrose, sorbitol, ethylene glycol, propylene glycol). This substitution maintains the desired low viscosity while eliminating the harmful steam blows that occur when water evaporates under press conditions.
2Shape
If urea is used as a non-volatile denaturant/diluent to lower viscosity, then the adhesive viscosity decreases while maintaining solids, but a non-urea alternative is desirable in the market place
Solution Approach 1:
The patent replaces urea (a conventional but less desirable diluent) with alternative non-volatile diluents such as glycerol, sucrose, sorbitol, ethylene glycol, and propylene glycol. These alternatives achieve the same technical function of lowering viscosity while maintaining solids content, but are more acceptable to the market due to their safety and performance characteristics.
3Ease of operation
If more water is added to lower viscosity for spray application, then the adhesive viscosity decreases, but too much water causes steam blows or requires long press times
Solution Approach 1:
The patent modifies the adhesive system by substituting water with non-volatile diluents (glycerol, sucrose, sorbitol, ethylene glycol, propylene glycol). This parameter change enables spray application with adequate flow characteristics while preventing steam blows and reducing press time, since the diluents do not evaporate under press conditions.
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 non-urea diluents like glycerol and sucrose in adhesive compositions for lignocellulosic substrates achieves lower viscosity without compromising adhesive strength, offering a viable alternative to urea-based systems, particularly in applications like particleboard and MDF production.
Implementation Method 1
adding selected non-volatile additives other than urea to essentially formaldehyde-free crosslinker containing adhesive formulations can maintain good adhesive properties while providing lower formulation viscosities
Implementation Method 2
a crosslinker (cross linking agent) and a non-urea diluent where the non-urea diluent is present in an amount from about 0.01 to about 75 weight % based on the total wet weight of the composition
Implementation Method 3
The adhesive composition is cured by heat
Data Source
AI summary
The disclosure relates to an adhesive composition for bonding lignocellulosic substrates. The adhesive composition contains a crosslinker and a non-urea diluent where the non-urea diluent is present in an amount from about 0.01 to about 75 weight % based on the total wet weight of the composition and where the crosslinker contains essentially no formaldehyde. Also disclosed is the adhesive further containing. an aqueous mixture of a protein source. The disclosure also relates to a process for making lignocellulosic composites utilizing the disclosed adhesive composition and to the lignocellulosic composites made using the disclosed process.