Melamine-Urea-Formaldehyde Adhesive System for Low Formaldehyde Emissions

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Solution Overview

Problem

Amino resin-based adhesive systems used in wood products often release formaldehyde, leading to health concerns and requiring high press temperatures or long press times for effective bonding, which increase energy consumption and reduce production capacity.

Innovation Solution

An adhesive system comprising a melamine-urea-formaldehyde resin with a melamine content of 30-60 wt% and a formaldehyde to nitrogen molar ratio of 0.6-0.79, combined with a hardener component containing acids or acid-generating salts and minimal urea, to reduce formaldehyde emissions without extending press time or increasing temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If significant amounts of urea scavenger are added to reduce formaldehyde emissions, then formaldehyde emissions are reduced, but press time increases and/or press temperature increases

Engineering Contradiction:
Improveformaldehyde emissionsVSAvoidpress time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive system by using a MUF resin with specific F/NH2 molar ratio (0.6-0.79) and melamine content (30-60 wt%), combined with a hardener containing acid or acid-generating salt and limited urea (less than 15 wt%). This parameter optimization reduces formaldehyde emissions while maintaining acceptable press times without requiring excessive urea addition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive system combining MUF resin with specific properties (controlled F/NH2 ratio and melamine content) and a specialized hardener composition (acid/acid-generating salt with limited urea). This composite approach achieves low formaldehyde emissions and adequate bonding performance without the need for high urea content scavengers that would extend press time.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If significant amounts of urea scavenger are added to reduce formaldehyde emissions, then formaldehyde emissions are reduced, but press temperature increases

Engineering Contradiction:
Improveformaldehyde emissionsVSAvoidpress temperature
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The patent optimizes the chemical parameters of the adhesive system by controlling the F/NH2 molar ratio (0.6-0.79) and melamine content (30-60 wt%) in the MUF resin, combined with a hardener containing acid or acid-generating salt and limited urea (less than 15 wt%). This formulation achieves low formaldehyde emissions without requiring high press temperatures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful high formaldehyde emissions into a benefit by carefully controlling the resin composition and using acid/acid-generating salt in the hardener to neutralize formaldehyde release during curing. This approach reduces emissions without the need for high temperatures or excessive urea addition.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If high press temperature is used to achieve satisfactory bonding, then bonding quality is improved, but energy consumption increases

Engineering Contradiction:
Improvebonding qualityVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The patent changes the adhesive system parameters by using MUF resin with F/NH2 molar ratio of 0.6-0.79 and melamine content of 30-60 wt%, combined with a hardener containing acid or acid-generating salt and less than 15 wt% urea. This formulation achieves satisfactory bonding quality at moderate press temperatures, reducing energy consumption compared to conventional high-temperature processes.

Inventive Principle:
Principle #35Parameter changes

4Strength

If long press time is used to achieve satisfactory bonding, then bonding quality is improved, but production capacity decreases

Engineering Contradiction:
Improvebonding qualityVSAvoidproduction capacity
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent optimizes the adhesive system composition by using MUF resin with controlled F/NH2 molar ratio (0.6-0.79) and melamine content (30-60 wt%), combined with a hardener containing acid or acid-generating salt and limited urea (less than 15 wt%). This formulation achieves satisfactory bonding quality within acceptable press times, maintaining production capacity without requiring excessively long press durations.

Inventive Principle:
Principle #35Parameter changes

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 solution enables efficient bonding of wood materials with low or no formaldehyde emissions, maintaining production efficiency by reducing press time and energy consumption while meeting bonding quality standards.

Implementation Method 1

a hardener component comprising at least one acid, acid generating salt or acidic salt

Methodology Applied
Scientific EffectAcid catalysis: Catalysis

Implementation Method 2

Upon curing an amino resin, formaldehyde may be released both when used in the manufacturing of wood based products and also later during use of those products

Methodology Applied
Scientific EffectFormaldehyde release: Decomposition (biological)

Data Source

PatentEP2872583B1Adhesive system
Publication Date: 2016.05.04 AKZO NOBEL COATINGS INT BV

AI summary

The invention concerns an adhesive system comprising: (a) a resin component comprising a melamine-urea-formaldehyde resin in which the amount of melamine expressed as M/(M+U) is from 26 to 99 wt% and the F/NH2 molar ratio is from 0.6 to 0.79; and, (b) a hardener component comprising at least one acid, acid generating salt or acidic salt and being free from or comprising less than 15 wt% urea. The invention further concerns use thereof, a method of producing a wood based product and products obtainable thereby.