Urea-Formaldehyde Glue Ratio Control Using NIR Feedback

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Solution Overview

Problem

The production of urea-formaldehyde glue for wood-based boards faces challenges due to inconsistent formaldehyde/urea molar ratios, leading to issues such as slower production, insufficient substrate strength, and excessive formaldehyde emissions, particularly when using recycled wood waste with varying compositions.

Innovation Solution

Implementing near-infrared (NIR) measurements at multiple locations during the production of urea-formaldehyde concentrate (UFC) and using calibration models to accurately determine the formaldehyde/urea molar ratios, allowing for real-time adjustments and ensuring uniformity and quality of the glue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the formaldehyde/urea molar ratio is increased to improve substrate strength and production speed, then the strength and production efficiency are improved, but formaldehyde emissions become excessive

Engineering Contradiction:
Improvesubstrate strengthVSAvoidformaldehyde emissions
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent implements a feedback control system where NIR measurements continuously monitor the formaldehyde/urea molar ratio in the urea-formaldehyde concentrate. The measured ratio is compared against target values, and adjustments are automatically made to the formaldehyde and urea dosing rates to maintain the optimal ratio, thereby achieving substrate strength improvement without excessive formaldehyde emissions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the formaldehyde/urea molar ratio parameter based on real-time NIR measurements. By changing this critical parameter within optimal ranges (0.8-1.2), the system achieves the desired balance between substrate strength and formaldehyde emission control

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the formaldehyde/urea molar ratio is decreased to reduce formaldehyde emissions, then emissions are reduced, but production speed and substrate strength become insufficient

Engineering Contradiction:
Improveformaldehyde emissionsVSAvoidproduction speed
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The feedback control system continuously monitors the formaldehyde/urea molar ratio and automatically adjusts dosing rates to maintain optimal values. This ensures that production proceeds at optimal speed with adequate substrate strength while keeping formaldehyde emissions within acceptable limits

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static, fixed-ratio mixing to dynamic, real-time ratio adjustment. The formaldehyde and urea dosing rates are continuously adapted based on NIR measurements, allowing the system to respond to variations in raw material composition and maintain optimal production conditions

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If recycled wood waste is used to improve sustainability, then environmental benefits are achieved, but composition variability causes inconsistent glue performance

Engineering Contradiction:
Improveuse of recycled materialVSAvoidcomposition uniformity
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The NIR-based feedback system compensates for composition variability in recycled wood waste by continuously monitoring the actual formaldehyde/urea ratio in the concentrate and making real-time adjustments to dosing rates, ensuring consistent glue performance regardless of raw material variations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system adjusts the formaldehyde/urea molar ratio parameter dynamically to compensate for variations in recycled material composition, maintaining optimal glue performance across different batches of recycled wood waste

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If manual measurement and adjustment methods are used to determine molar ratios, then equipment complexity is reduced, but measurement precision and production speed are insufficient

Engineering Contradiction:
Improvemeasurement system complexityVSAvoidmolar ratio accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces manual, mechanical measurement methods with NIR (near-infrared) spectroscopy. This optical measurement system provides rapid, precise determination of the formaldehyde/urea molar ratio without complex mechanical intervention, achieving high measurement precision while maintaining relatively simple equipment

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The NIR system creates an optical copy or spectral fingerprint of the urea-formaldehyde concentrate composition, allowing rapid and accurate determination of the formaldehyde/urea ratio without physical manipulation or complex mechanical analysis

Inventive Principle:
Principle #26Copying

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 method enhances the accuracy and speed of urea-formaldehyde glue production, resulting in more uniform and higher-quality boards with reduced formaldehyde emissions and improved adhesion, pressing efficiency, and reduced need for corrective measures.

Implementation Method 1

near-infrared (NIR) measurements at multiple locations during the production of urea-formaldehyde concentrate (UFC) and using calibration models to accurately determine the formaldehyde/urea molar ratios

Methodology Applied
Scientific EffectNear-infrared absorption: Absorption (EM radiation)

Data Source

PatentEP4461492B1Method for producing a urea-formaldehyde glue
Publication Date: 2026.04.08 UNILIN BVBA
  • EP4461492B1 patent drawingFigure 1
  • EP4461492B1 patent drawingFigure 2
  • EP4461492B1 patent drawingFigure 3

AI summary

Method for producing a urea-formaldehyde glue, wherein raw materials of the glue are combined in a reactor (1), wherein these raw materials at least comprise a urea-formaldehyde concentrate, wherein formaldehyde/urea molar ratios of the urea-formaldehyde concentrate are determined on the basis of NIR measurements and at least one calibration model, and wherein the raw materials are dosed into the reactor (1) on the basis of said formaldehyde/urea molar ratios of the urea-formaldehyde concentrate.