Foam Coater and High-Consistency Press for Paperboard Sizing

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Solution Overview

Problem

Existing paper and paperboard manufacturing methods face challenges with surface sizing, including high water usage, increased energy costs for drying, and limited effectiveness in achieving internal bond strength and penetration of sizing agents, particularly in paperboard production.

Innovation Solution

A method involving the application of a first binder composition in a foamed form onto a web, followed by a second binder composition with higher solids content, applied in a non-foamed form using a high-consistency metering size press, to enhance inter-ply and intra-ply strength and reduce drying costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If surface sizing is applied using conventional methods with starch solutions, then surface strength and absorption properties are improved, but water content in the web increases significantly, leading to higher drying energy costs

Engineering Contradiction:

Improvesurface strengthVSAvoiddrying energy cost

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The invention changes the physical state of the binder from liquid solution to foam form. The foam contains binder at lower concentration (0.1-20% solids) dispersed in gas bubbles, which allows application without significantly increasing water content in the web. After drying, the foam leaves behind binder deposits that provide surface strength without the water loading problem of conventional liquid sizing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transition from liquid binder solution to foam structure. The foam coater transforms liquid binder into a foamed composition that can be applied to the web and then collapses during drying, leaving binder residues that provide sizing function without the water content penalty of conventional liquid application

Inventive Principle:

Principle #36Phase transitions

2Strength

If high molecular weight and high branching starch is used to improve internal bond strength, then penetration into the ply-zone is reduced, but internal bond strength is improved

Engineering Contradiction:

Improveinternal bond strengthVSAvoidpenetration depth of sizing agent

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The invention changes the physical form of binder application from liquid to foam. The foam structure allows binder to be delivered in a controlled manner that enables penetration to the ply-zone interface without requiring high molecular weight starch. The foam collapses during drying, distributing binder effectively at the ply interface for internal bond strength

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The foam coater applies binder to the web surface before the plies are fully formed and bonded. This preliminary application allows the binder to be positioned at the ply-zone interface where it will provide internal bond strength, without needing to penetrate deeply into already-formed dense plies

Inventive Principle:

Principle #10Preliminary action

3Strength

If large amount of sizing solution is applied to achieve effective concentration in the ply-zone, then internal bond strength is improved, but water content and drying energy requirements increase

Engineering Contradiction:

Improveinternal bond strengthVSAvoidamount of sizing solution

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The invention uses foam phase transition to deliver binder efficiently. The foam structure concentrates binder in gas bubbles that collapse during drying, delivering binder precisely where needed at the ply-zone interface without applying large amounts of water. This phase transition enables effective binder delivery with minimal water content increase

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The foam coater changes the delivery mechanism from liquid solution to foamed composition. This allows application of binder at lower solids content (0.1-20%) in foam form, which translates to much lower water content compared to liquid sizing solutions, while still achieving effective binder concentration at the ply-zone for internal bond strength

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

This approach improves the internal bond strength and resistance to delamination, optimizes binder properties, and reduces drying energy consumption, enabling more efficient production with better product quality.

Implementation Method 1

applying a first binder composition in the form of a foamed composition onto the web

Methodology Applied

Scientific EffectFoam: Foam

Implementation Method 2

applying a second binder composition onto the web with a high-consistency metering size press

Methodology Applied

Scientific EffectPressure: Pressure Increase

Data Source

PatentUS20240229361A9A method, a paperboard product and use of a foam coater and a subsequent high-consistency metering size press

Publication Date: 2024.07.11 METSA BOARD

AI summary

According to an example aspect of the present invention, there is provided a method comprising: providing a web comprising fibrous material; applying a first binder composition in the form of a foamed composition onto the web; and subsequently applying a second binder composition onto the web; wherein the second binder composition has a higher solids content than the first binder composition.