Cellulose-Reactive Sizing Agent Dispersion for Papermaking

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Solution Overview

Problem

Aqueous dispersions of alkenyl succinic anhydride used in papermaking exhibit poor stability and require high shear forces for preparation, leading to equipment complexity and high energy consumption, with limited storage duration due to hydrolysis issues.

Innovation Solution

An aqueous dispersion of cellulose-reactive sizing agent containing an acid anhydride, an anionic polyelectrolyte, and a nitrogen-containing organic compound, which can be prepared using low shear forces and low energy, improving stability and sizing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional dispersant systems with high molecular weight polymers are used, then dispersion stability is improved, but device complexity and energy consumption increase due to required high shear forces

Engineering Contradiction:

Improvedispersion stabilityVSAvoidequipment complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention changes the molecular weight parameter of the dispersant from high molecular weight (conventional) to low molecular weight (up to 160), which fundamentally alters the dispersion mechanism and eliminates the need for high shear force equipment while maintaining stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The nitrogen-containing organic compound acts as an intermediary that facilitates dispersion through chemical interaction with the acid anhydride, replacing the need for complex mechanical dispersant systems

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If conventional dispersant systems with high molecular weight polymers are used, then dispersion stability is improved, but energy consumption increases due to required high shear forces

Engineering Contradiction:

Improvedispersion stabilityVSAvoidenergy consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by stationary object

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical dispersant system (requiring high shear forces) with a chemical system based on low molecular weight compounds that provide dispersion through molecular-level interactions rather than mechanical forces

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If alkenyl succinic anhydride is stored as aqueous dispersion, then handling is simplified, but storage duration is limited due to hydrolysis

Engineering Contradiction:

Improvehandling easeVSAvoidstorage duration

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The invention accepts the limited stability of aqueous dispersions but compensates by using the dispersion immediately after simple preparation, treating it as a short-living but easily prepared sizing agent that doesn't require long-term storage

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention performs preliminary dispersing action using simple equipment before use, ensuring the sizing agent is ready for immediate application without requiring long-term storage stability

Inventive Principle:

Principle #10Preliminary action

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 allows for the use of simple and energy-efficient equipment, such as static mixers, resulting in stable dispersions with enhanced sizing performance and extended storage capabilities.

Implementation Method 1

dispersing an acid anhydride in an aqueous phase in the presence of an anionic polyelectrolyte and a nitrogen-containing organic compound

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

anionic polyelectrolyte and a nitrogen-containing organic compound which is an amine or quaternary ammonium

Methodology Applied

Scientific EffectElectrostatic interaction: Electrostatics

Data Source

PatentEP1963575B1Sizing of paper

Publication Date: 2014.06.04 CHEM FAB BRUHL MARE

AI summary

The invention relates to an aqueous dispersion of cellulose-reactive sizing agent containing an acid anhydride, an anionic polyelectrolyte and a nitrogen-containing organic compound which is an amine or quaternary ammonium thereof having a molecular weight less than 180 and/or having one or more hydroxyl groups. The invention further relates to a method for the preparation of an aqueous dispersion of cellulose-reactive sizing agent which comprises dispersing an acid anhydride in an aqueous phase in the presence of an anionic polyelectrolyte and a nitrogen-containing organic compound which is an amine or quaternary ammonium thereof having a molecular weight less than 180 and/or having one or more hydroxyl groups. The invention also relates to the use of the aqueous dispersion of cellulose-reactive sizing agent as a stock sizing agent or surface sizing agent in the production of paper. The invention further relates to a process for the production of paper which comprises adding the aqueous dispersion of cellulose-reactive sizing agent to an aqueous cellulosic suspension.