GPAM and Amine Polymer Crosslinking for Paper Strength
Solution Overview
Problem
The papermaking process faces challenges in simultaneously enhancing dry strength, surface strength, and drainage retention while maintaining the integrity of other attributes and additives in the paper product, as existing methods often compromise one attribute to improve another.
Innovation Solution
A method involving the use of a GPAM polymer and an amine-containing polymer, such as a diallylamine acrylamide (DAA/AcAM) polymer, is applied at the wet end of the papermaking process, where they can crosslink to form higher molecular weight molecules, enhancing the strength of the paper without interfering with other additives or degrading paper flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dry strength agents are added to the slurry to increase dry strength, then dry strength is improved, but drainage retention and effectiveness of other additives are compromised
Solution Approach 1:
The invention uses a composite polymer system combining GPAM (glyoxalated polyacrylamide) with amine-containing polymers (such as polyamine or polyDADMAC). This composite approach creates synergistic effects where the GPAM provides dry strength enhancement while the amine-containing polymer maintains drainage retention, resolving the contradiction between improving dry strength and maintaining drainage performance
Solution Approach 2:
The invention changes the chemical parameters of the strength enhancement system by using specific polymer compositions with controlled molecular weights, charge densities, and functional groups. The GPAM polymer contains glyoxal groups that react with cellulose, while the amine-containing polymer provides cationic charge for fiber bonding, creating a balanced system that improves dry strength without compromising drainage
2Strength
If surface strength agents are applied as coatings to increase resistance to abrasive forces, then surface strength is improved, but flexibility and compatibility with other additives are degraded
Solution Approach 1:
The invention extracts the surface strength function from separate coating applications and integrates it into the wet-end polymer system. The amine-containing polymer provides surface strength enhancement during the papermaking process itself, eliminating the need for separate coating operations that would compromise flexibility and compatibility with other additives
Solution Approach 2:
The amine-containing polymer performs multiple functions simultaneously: it provides cationic charge for fiber bonding, enhances surface strength, maintains drainage retention, and ensures compatibility with sizing agents and optical brightening agents. This multi-functional approach resolves the contradiction between improving surface strength and maintaining flexibility
3Quantity of substance
If higher filler particle content is incorporated to improve optical properties and reduce cost, then optical properties and cost are improved, but strength is reduced
Solution Approach 1:
The GPAM-amine polymer system acts as an intermediary between filler particles and cellulose fibers. The polymers create strong bonding interfaces that hold filler particles securely within the paper matrix, allowing high filler content to be incorporated without compromising strength. The cationic amine-containing polymer particularly effective at bridging negatively charged filler surfaces with cellulose fibers
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 results in a paper product with increased strength, improved drainage retention, and the ability to incorporate higher filler particle content, leading to superior optical properties and cost savings, while maintaining flexibility and avoiding the loss of surface strength.
Implementation Method 1
The GPAM and the amine containing polymer may crosslink to produce a higher molecular weight molecule
Data Source
AI summary
The invention provides methods and compositions for increasing the strength of a paper sheet. The method involves adding to the paper sheet an amine containing polymer. The amine containing polymer interacts with materials such as GPAM or starch to make the paper stronger in terms including tensile strength, surface strength and bulk strength.