Anionic Polymeric Microparticles for Paper Strength
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Solution Overview
Problem
Current papermaking processes face challenges in achieving improved internal bond strength and wet web strength, particularly due to issues with starch addition leading to excessive bacteria growth, slime formation, and runnability problems, such as machine plugging and increased biocide use.
Innovation Solution
Incorporating anionic organic polymeric microparticles formed from a composition of acrylic anionic and non-ionic monomers into the cellulosic thick stock, which are then diluted and drained to form a web, enhancing wet web strength and reducing the need for starch addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If starch is added in the wet end section to improve paper strength, then internal bond strength is improved, but bacteria growth and slime formation increase excessively
Solution Approach 1:
The invention extracts and removes starch from the papermaking process by replacing it with anionic polymeric microparticles. This substitution eliminates the source of bacteria growth and slime formation while maintaining the necessary bonding function through alternative mechanisms involving the polymeric microparticles that do not support excessive microbial growth
Solution Approach 2:
The patent employs anionic polymeric microparticles as a temporary, non-biodegradable alternative to starch. These microparticles perform the bonding function during the papermaking process and in the final product without the long-term environmental and hygiene issues associated with starch, particularly the excessive bacteria growth and slime formation in white water systems
2Strength
If native starch is sprayed onto the forming web to improve strength, then paper strength is improved, but machine runnability deteriorates due to nozzle plugging
Solution Approach 1:
The invention removes the starch spraying operation from the papermaking process by incorporating anionic polymeric microparticles directly into the stock. This eliminates the need for external spraying equipment and nozzles, thereby removing the plugging problem entirely while still achieving the desired strength improvement through internal bonding mechanisms
Solution Approach 2:
The anionic polymeric microparticles serve as an intermediary substance that performs the bonding function internally within the stock rather than being applied externally. This intermediate approach allows the microparticles to be distributed uniformly during the normal papermaking process without requiring separate spraying equipment, thus avoiding runnability issues
3Strength
If starch is added to improve wet web strength for better runnability, then wet web strength is improved, but the collected white water contains starch leading to increased biocide requirements
Solution Approach 1:
The invention extracts starch from the system by replacing it with anionic polymeric microparticles. This substitution eliminates the organic substrate that would otherwise feed bacteria in the white water, thereby removing the need for increased biocide application while maintaining adequate wet web strength through the polymeric microparticles
Solution Approach 2:
The patent converts the potential harm of adding strength-improving chemicals into a benefit by selecting anionic polymeric microparticles that provide the necessary wet web strength enhancement while simultaneously reducing or eliminating the harmful effect of promoting bacterial growth in white water, thus reducing biocide requirements
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 process significantly improves wet web strength and machine runnability, allowing for reduced starch use and minimizing slime formation, thus reducing biocide requirements and simplifying the papermaking process.
Implementation Method 1
Incorporating anionic organic polymeric microparticles formed from a composition of acrylic anionic and non-ionic monomers into the cellulosic thick stock
Implementation Method 2
the organic polymeric microparticles are formed from a composition comprising at least one acrylic anionic monomer and at least one acrylic non-ionic monomer
Implementation Method 3
the acrylic anionic monomer is at least one of (meth)acrylic acid; 2-acrylamido-2-methyl-1-propanesulfonic acid; or salts thereof
Data Source
Figure 1
AI summary
The present invention provides a process for preparing a paper or paper board of improved strength which comprises the steps of i) providing a cellulosic thick stock, ii) diluting the thick stock of step i) to form a thin stock, iii) draining the thin stock of step ii) on a wire to form a web, and iv) drying the web of step iii) to form paper or paper board, wherein the cellulosic thick stock of step (i) comprises organic polymeric microparticles, as well as paper obtainable by above process.