Floor Panel Backing Layer for Moisture and Formaldehyde Control

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Solution Overview

Problem

Conventional wood-based panels without a backing layer face issues with moisture-induced swelling and elevated formaldehyde emissions, particularly at panel joints, due to the lack of a backing layer which increases the diffusion of moisture and volatile compounds.

Innovation Solution

A wood-based panel with a decorative coating on the visible side and a backcoat containing a formaldehyde-binding component, such as polyamine, and a water vapor transmission-resistant layer, preferably a polymer-based copolymer, applied on the backside to enhance water vapor resistance and pollutant binding, with a water vapor transmission resistance of at least 200 x 10^6 (m2 s Pa)/kg and a basis weight of 9 to 20 g/m².

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a conventional back coat is applied to the rear side of the panel, then the panel achieves a higher quality appearance through coloring, but moisture from the substrate diffuses easily into the carrier board causing swelling at panel joints

Engineering Contradiction:
Improveappearance qualityVSAvoiddimensional stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The back coat is formulated with specific components including water vapor diffusion-resistant substances (wax, resin, oil) and formaldehyde-binding components (polyamines) in controlled concentrations. The water vapor diffusion resistance number is optimized to at least 150, and the coating weight per unit area is controlled at 5-20 g/m², creating a functional barrier while maintaining appearance quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The back coat uses a composite formulation combining multiple functional ingredients: water vapor diffusion-resistant substances (wax, resin, or oil), formaldehyde-binding polyamines, and additional functional components. This composite approach allows simultaneous achievement of moisture barrier properties, formaldehyde emission reduction, and aesthetic appearance

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If the carrier board lacks effective vapor barriers, then the manufacturing process is simpler, but formaldehyde emissions from the carrier board exceed permissible limit values

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidformaldehyde emissions
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The back coat acts as an intermediary layer between the carrier board and the external environment. It contains formaldehyde-binding components (polyamines) that chemically bind formaldehyde emissions from the carrier board, and water vapor diffusion-resistant substances that create a barrier, thereby reducing formaldehyde emissions to below permissible limits while maintaining manufacturing simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The back coat converts the harmful formaldehyde emissions and moisture vapor from the carrier board into beneficial effects. The polyamines bind formaldehyde, and the water vapor diffusion-resistant substances trap moisture, transforming potential harm into a protective function that improves air quality and dimensional stability

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

3Shape

If impregnated paper is applied on both sides of the panel, then the panel remains flat and does not bowl, but the coating material shrinks during pressing generating tension that requires counter-tension

Engineering Contradiction:
ImproveflatnessVSAvoidinternal tension
Core Design Contradiction:
ShapeVSStress or pressure

Solution Approach 1:

The back coat is applied with controlled parameters: weight per unit area of 5-20 g/m², water vapor diffusion resistance number of at least 150, and specific functional component concentrations. These optimized parameters provide sufficient counter-tension to maintain panel flatness while minimizing internal stress generation during the pressing process

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 significantly reduces swelling and formaldehyde emissions by 50% compared to conventional panels, maintaining dimensional stability and improving moisture resistance, while the increased backcoat application by 40-60% is sufficient to achieve these results.

Implementation Method 1

the back line at least one component increasing the water vapor diffusion resistance and contains at least one air pollutant-binding, in particular formaldehyde-binding component, and wherein the back coat of the panel according to the invention has a water vapor diffusion resistance number of at least 150

Methodology Applied
Scientific EffectWater vapor diffusion resistance: Diffusion Barrier

Implementation Method 2

contains at least one air pollutant-binding, in particular formaldehyde-binding component

Methodology Applied
Scientific EffectFormaldehyde binding: Adsorption

Implementation Method 3

the material of the back coat contains a water repellent

Methodology Applied
Scientific EffectWater repellency: Hydrophobe

Data Source

PatentEP2331642A1Panels, in particular floor panels
Publication Date: 2011.06.15 FRITZ EGGER GMBH & CO OG

AI summary

The invention relates to a panel (1, 1'), in particular a floor panel, comprising a support plate (1.1) made of wood material, the visible or top side of said plate being provided with a decorative coating (1.2) applied by way of a printing method, and the rear side thereof being provided with a backing layer (1.3), preferably a colored backing layer. For such a panel (1, 1') to have improved properties with regard to resistance to moisture and to the emission of air pollutants, the invention provides that the backing layer (1.3) contains at least one component that increases the water vapor diffusion flow resistance and at least one component that binds air pollutants, in particular formaldehyde, wherein the improvement of the water vapor diffusion flow resistance of the support plate (1.1) provided with the backing layer (1.3) is at least 200 x 106 m2 s Pa/kg, preferably at least 260 x 106 m2 s Pa/kg, and more preferably at least 290 x 106 m2 s Pa/kg.