Cementitious Board Adhesive Foam for Overlap Bonding

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Solution Overview

Problem

Conventional methods for producing cementitious boards face challenges in achieving adequate adhesion between liners and the cementitious core, particularly in overlap sections, while also reducing adhesive consumption to prevent irregular spreading and air inclusions.

Innovation Solution

The method involves using adhesive foam in the overlap sections of cementitious boards, which reduces the overall adhesive amount while maintaining sufficient adhesion quality. The adhesive foam is generated by reducing the density of the adhesive, typically by a factor of 2 to 15, and is applied in a controlled manner to ensure effective bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the amount of adhesive is reduced to decrease adhesive consumption, then adhesive cost is reduced, but adhesion quality deteriorates and irregular spreading occurs

Engineering Contradiction:

Improveadhesive consumptionVSAvoidadhesion quality

Core Design Contradiction:

Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the physical state of the adhesive from liquid to foam form. This parameter change allows the adhesive to be applied in a reduced amount while maintaining effective adhesion, as the foam structure provides better distribution and contact with the substrate surface.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The adhesive is transformed from liquid phase to foam phase before application. This phase transition enables the adhesive to achieve better spreading characteristics and adhesion quality with reduced material consumption, as the foam structure allows for more uniform distribution across the overlap sections.

Inventive Principle:

Principle #36Phase transitions

2Strength

If a relatively large amount of adhesive is used to improve adhesion, then adhesion strength is improved, but vapor diffusion rate decreases due to reduced porosity

Engineering Contradiction:

Improveadhesion strengthVSAvoidvapor diffusion rate

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent uses adhesive foam, which is inherently a porous material with a cellular structure. This porous structure allows vapor to diffuse through the adhesive layer while the foam maintains adhesion strength through its bonded structure. The porosity of the foam resolves the contradiction by enabling both adhesion and vapor transmission.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

By transitioning the adhesive to foam phase, the material inherently possesses porous characteristics that allow vapor diffusion. The foam structure maintains sufficient adhesion strength while creating pathways for vapor to pass through, eliminating the need to choose between adhesion strength and vapor diffusion rate.

Inventive Principle:

Principle #36Phase transitions

3Loss of substance

If adhesive is applied as a thin trace and spread conventionally, then adhesive consumption is reduced, but irregular spreading occurs resulting in air inclusions

Engineering Contradiction:

Improveadhesive consumptionVSAvoidadhesive distribution uniformity

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The adhesive is applied in foam form rather than liquid trace form. The foam structure naturally spreads more uniformly across the surface due to its gas-filled cellular structure, which distributes the adhesive material evenly while maintaining consistent thickness and avoiding air inclusions.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The foam structure acts as an intermediary form between liquid adhesive and the final bonded state. This intermediate foam phase facilitates uniform distribution across the overlap sections, preventing the irregular spreading and air inclusions that occur with conventional liquid adhesive application.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enhances the vapor diffusion rate in the overlap sections by at least 10% compared to boards bonded with non-foamed adhesive, while preventing air inclusions and ensuring proper adhesion, thus producing high-quality cementitious boards with reduced adhesive usage.

Implementation Method 1

the first liner and the second liner are bonded via the adhesive foam in the overlap sections

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

the vapor diffusion rate in the overlap section is increased by at least 10% compared to a same cementitious board, the liners of which are bonded by the same but non-foamed adhesive

Methodology Applied

Scientific EffectVapor diffusion: Diffusion

Data Source

PatentUS12330333B2Method for producing a cementitious board, apparatus for producing a cementitious board, and cementitious board

Publication Date: 2025.06.17 KNAUF GIPS KG

AI summary

An apparatus for producing a cementitious board includes a conveying device for conveying a first liner with first overlap sections-in a transport direction, at least one slurry feeder device for applying at least one layer of at least one slurry comprising a cementitious material onto the first liner, a liner feeding device for providing and arranging a second liner with second overlap sections such that it contacts the first overlap sections of the first liner wherein the at least one layer of the at least one slurry is arranged between the first liner and the second liner, an adhesive foam feeder for providing an adhesive foam on at least one of the first or the second overlap sections, and a means for bonding the first liner and the second liner.