Filler Surface Treatment with Natural Gums for Paper Strength
Solution Overview
Problem
High filler content in papermaking decreases the efficiency of wet end chemicals, leading to reduced wet web strength and dewatering efficiency, particularly with PCC fillers due to their larger surface area interfering with fiber bonds and coating wet strength aids, making it challenging to increase filler content without compromising paper strength and production efficiency.
Innovation Solution
Treating filler particles with a composition comprising natural gums like xanthan gum or guar gum to reduce the adsorption of wet strength aids and drainage aids, combined with a wet web strength additive such as GPAM, to enhance the strength of the paper and improve dewatering efficiency by increasing the viscosity of the filler composition and preventing excessive coating of additives on filler particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PCC filler is used to increase filler content, then light scattering ability and optical properties are improved, but wet web strength and dry strength are reduced
Solution Approach 1:
A cationic starch-gum arabic complex acts as an intermediary between PCC filler particles and cellulose fibers. The complex coats the filler surface, reducing excessive adsorption of wet strength aids while improving filler-fiber bonding. This mediator enables high PCC content (up to 80% or more) to be used without sacrificing wet web strength, resolving the contradiction between light scattering ability and strength retention.
Solution Approach 2:
The invention uses a composite material system consisting of cationic starch combined with gum arabic to treat the filler surface. This composite coating on PCC particles provides both optical properties and mechanical strength by controlling the interaction between filler and fibers, allowing simultaneous achievement of high light scattering and adequate wet web strength.
2Quantity of substance
If high filler content is used, then paper cost is reduced and opacity is improved, but efficiency of wet end chemicals is decreased
Solution Approach 1:
The cationic starch-gum arabic complex serves as a mediator that prevents excessive adsorption of drainage aids and wet strength aids on filler surfaces. By controlling this adsorption, the complex maintains chemical efficiency even at high filler contents (80% or more), resolving the contradiction between high filler content and dewatering efficiency.
Solution Approach 2:
The invention changes the surface charge parameters of filler particles by coating with cationic starch-gum arabic complex. This parameter change reduces the affinity between filler surface and wet end chemicals, preventing excessive adsorption and maintaining dewatering efficiency at high filler concentrations.
3Quantity of substance
If high filler content is used, then paper cost is reduced, but wet web strength is reduced due to interference with fiber bonds
Solution Approach 1:
The cationic starch-gum arabic complex acts as an intermediary that improves filler-fiber bonding mechanisms. It coats the filler surface and creates stronger bonding sites, allowing high filler content to be used without compromising wet web strength. The complex enables filler particles to contribute positively to web strength rather than interfering with fiber bonds.
4Strength
If more wet strength aids are used to compensate for filler interference, then wet web strength is improved, but operational costs increase and equipment issues occur
Solution Approach 1:
The cationic starch-gum arabic complex acts as a preliminary treatment that reduces the need for excessive wet strength aids. By improving filler-fiber bonding and controlling chemical adsorption, the complex allows adequate wet web strength to be achieved with reduced additive usage, lowering operational costs and avoiding equipment issues associated with high additive concentrations.
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 synergy between natural gums and wet web strength additives results in significantly increased paper strength and dewatering efficiency, overcoming the limitations of high filler content and achieving greater strength improvements than either component alone, while reducing the operational costs and equipment issues associated with high additive usage.
Implementation Method 1
increasing the viscosity of the filler composition and preventing excessive coating of additives on filler particles
Implementation Method 2
decreases the efficiency of wet end chemicals, such as dewatering aids, wet web strength aids and wet strength aids
Data Source
AI summary
The invention provides a method of improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength and enhancing filler retention in a papermaking process The method improves the efficiency of drainage aids or wet web strength aids or wet strength aid by coating at least some of the filler particles with a natural gum and with a material that prevents the filler materials form adhering to those additives. The drainage additive or wet web strength additive or wet strength aid holds the cellulose fibers together tightly and is not wasted on the filler particles.