Biocide Treatment for Starch Preservation in Papermaking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for manufacturing paper, paperboard, or cardboard face challenges in achieving optimal strength and efficiency due to microbiological degradation of starch in waste paper, leading to increased electrical conductivity and higher consumption of dry and/or wet strength polymers in partially or fully closed water circuits.
Innovation Solution
A method involving the use of biocides, specifically an inorganic ammonium salt in combination with a halogen source, added at different feeding points in the papermaking process to prevent microbiological degradation of starch, thereby reducing electrical conductivity and enhancing the performance of dry and/or wet strength polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If starch is used in waste paper pulping, then paper strength is improved, but microbiological degradation increases electrical conductivity and reduces polymer effectiveness
Solution Approach 1:
The patent applies preliminary action by adding biocides to the pulping process before the starch undergoes microbiological degradation. The biocides are introduced at multiple feeding points in the pulping line to prevent microbial growth and starch degradation in advance, thereby maintaining starch effectiveness and reducing electrical conductivity before the paper formation stage.
Solution Approach 2:
The patent uses biocides as intermediary substances to mediate between the starch in waste paper and the microbiological contaminants. The biocides create a protective barrier that prevents direct microbial attack on the starch, allowing the starch to maintain its strength-enhancing properties without degradation.
2Strength
If dry and/or wet strength polymers are added to increase paper strength, then paper strength is improved, but polymer consumption increases cost and process complexity
Solution Approach 1:
The patent converts the harmful effect of microbiological degradation into a beneficial outcome by using biocides to prevent degradation. This preservation of starch integrity eliminates the need for excessive polymer additives, as the natural starch in the waste paper can maintain its strength properties without being degraded by microbes.
Solution Approach 2:
The patent changes the electrical conductivity parameter of the pulping system by adding biocides, which reduces it from high levels (caused by microbial degradation products) to lower levels. This parameter change creates favorable conditions for starch effectiveness and reduces the need for additional strength polymers.
3Object-affected harmful factors
If biocides are added to prevent starch degradation, then electrical conductivity is reduced and polymer performance is enhanced, but biocide addition increases process complexity
Solution Approach 1:
The patent applies segmentation by introducing biocides at multiple separate feeding points along the pulping line rather than using a single addition point. This segmented approach ensures comprehensive coverage of the pulping process, maintaining effective biocide concentration throughout the system while managing the complexity through systematic distribution.
Solution Approach 2:
The patent makes the biocide addition system multi-functional by serving multiple purposes: preventing microbial degradation of starch, controlling electrical conductivity, and creating optimal conditions for both natural starch and added polymer effectiveness. This multi-functionality justifies the process complexity by delivering multiple benefits from a single additive system.
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 significantly improves the dry and/or wet strength performance of paper products by reducing the need for strength polymers and minimizing starch degradation, resulting in more efficient paper production with lower polymer consumption and improved process control.
Implementation Method 1
preventing at least a portion of the starch from being microbially degraded by treating the aqueous cellulosic material containing the starch with one or more biocides
Implementation Method 2
the one or more biocides comprising an inorganic ammonium salt in combination with a halogen source
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
The invention relates to a method for manufacturing paper, paperboard or cardboard comprising the steps of (a) pulping an aqueous cellulosic material containing a starch; (b) preventing at least a portion of the starch from being microbialiy degraded by treating the aqueous cellulosic material containing the starch with one or more biocides; and (h) adding a dry and/or wet strength polymer to the cellulosic material.