Core-shell polymer particles for paper sizing
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Solution Overview
Problem
Current surface sizing systems for cellulosic products, such as paper, face challenges in achieving optimal water resistance and efficiency, as measured by the Cobb method, and often require expensive monomers.
Innovation Solution
The development of core-shell polymer particles with a specific monomer composition, where the core and shell are polymerized from a combination of branched alkyl (meth)acrylates, styrene, and acrylonitrile, with a high percentage of branched C3-10 alkyl (meth)acrylate in the shell, providing improved sizing performance and allowing for the replacement of expensive monomers without compromising efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional surface sizing systems are used, then water resistance is achieved, but expensive monomers are required and sizing efficiency can be improved
Solution Approach 1:
The invention uses composite polymer particles with a core-shell structure where the core contains hydrophobic branched alkyl (meth)acrylate monomers for water resistance and the shell contains styrene and acrylonitrile for durability and adhesion. This composite structure achieves superior sizing efficiency while reducing dependence on expensive traditional sizing monomers.
Solution Approach 2:
The core-shell structure distributes different functional properties to different regions: the core provides hydrophobicity for water resistance, while the shell provides mechanical durability and adhesion. This local differentiation of properties optimizes sizing performance across different functional requirements.
2Object-affected harmful factors
If high percentage of branched alkyl (meth)acrylate is used, then water resistance is improved, but cost increases
Solution Approach 1:
The invention optimizes the ratio of branched alkyl (meth)acrylate to other monomers (styrene and acrylonitrile) to achieve the minimum effective concentration for water resistance while reducing overall cost. The core-shell structure concentrates the hydrophobic monomers where most needed, allowing parameter optimization.
Solution Approach 2:
The invention replaces portions of expensive branched alkyl (meth)acrylate monomers with more cost-effective styrene and acrylonitrile in the shell structure, maintaining water resistance performance while reducing material costs.
3Reliability
If core-shell structure is used, then sizing efficiency is enhanced, but manufacturing complexity increases
Solution Approach 1:
The core-shell structure is formed through sequential polymerization where the core is formed first, followed by deposition of the shell material. This preliminary formation of the core structure simplifies the overall process compared to simultaneous formation of complex multifunctional particles.
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 core-shell polymer particles demonstrate enhanced sizing efficiency, reducing water absorptiveness of paper and maintaining performance even when reducing the ratio of branched alkyl (meth)acrylate, while also being cost-effective by using a styrene-free or reduced styrene formulation.
Implementation Method 1
the core polymer and the shell polymer of the core/shell polymer particle are polymerized from monomers comprising at least 40%, preferably at least 50%, by weight of monomers selected from branched C 3-10 -alkyl (meth)acrylate
Implementation Method 2
polymer particles having a core-shell structuring with a specific formulation have a sizing efficiency better than polymer particles containing the same monomers in a random polymer structure
Data Source
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AI summary
The present invention provides a core/shell polymer particle for surface sizing of cellulosic products, wherein the core polymer and the shell polymer of the core/shell polymer par- ticle are polymerized from monomers comprising at least 40%, by weight of monomers selected from branched C3-10- alkyl (meth)acrylate, styrene, linear C1-10-alkyl (meth)acry- late, and acrylonitrile, based on the total weight of the mon- omers of the core/shell polymer particle; provided that the polymer of the core/shell polymer particle comprises at least 40% by weight of branched C3-6-alkyl (meth)acrylate and at least 50% by combined weight of branched C3-10- alkyl (meth)acrylate and styrene, linear C1-10-alkyl (meth)acrylate, and/or acrylonitrile, based on the total weight of the monomers of the core/shell polymer particle.