Dextrin-Styrene Acrylic Copolymer for Paper Coating
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Solution Overview
Problem
Current solutions based on dextrins for enhancing the hydrophobicity of paper surfaces face challenges in achieving a high dextrin content while maintaining effective hydrophobic properties, as existing polymerization processes do not achieve a suitable balance between bio-sourced aspects and hydrophobicity.
Innovation Solution
A copolymer of dextrin and hydrophobic monomers, specifically styrene and acrylic esters, is developed with a dextrin content of at least 60% by weight, where the styrene:ester weight ratio ranges from 10:90 to 90:10, and the polymerization is optimized using a persulfate initiator system, ensuring high conversion rates and improved hydrophobicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dextrin content is increased to enhance bio-sourced aspects, then environmental friendliness improves, but hydrophobicity of the paper surface deteriorates
Solution Approach 1:
The patent creates a graft copolymer composite material where dextrin (bio-sourced) is chemically grafted with hydrophobic monomers (styrene and acrylic esters). This composite structure allows the hydrophobic monomers to be covalently bonded to the dextrin chains, providing hydrophobicity while maintaining the bio-sourced character of the dextrin backbone. The resulting copolymer exhibits both high dextrin content (≥60% by weight) and effective hydrophobic properties, resolving the contradiction between bio-sourced aspect and hydrophobicity.
2Object-affected harmful factors
If hydrophobic monomers are added to dextrin to improve hydrophobicity, then water resistance improves, but dextrin content decreases
Solution Approach 1:
The patent optimizes the parameters of the polymerization process, specifically controlling the monomer-to-dextrin ratio, polymerization temperature, and initiator concentration to achieve high conversion rates while maintaining high dextrin content in the final copolymer. By carefully adjusting these parameters, the patent achieves a balance where hydrophobic monomers are effectively incorporated (providing hydrophobicity) while dextrin remains the dominant component (≥60% by weight).
Solution Approach 2:
The graft copolymer structure provides local quality differentiation where hydrophobic monomer units are distributed along the dextrin chains. This creates localized hydrophobic regions that provide water resistance while the overall composition remains dominated by hydrophilic dextrin, achieving both high dextrin content and effective hydrophobicity through spatial distribution of properties.
3Productivity
If polymerization is optimized for high conversion rate, then monomer conversion improves, but control over molecular mass distribution becomes more difficult
Solution Approach 1:
The patent employs controlled polymerization conditions with specific initiators (persulfates) and temperature control that provide feedback mechanisms to regulate the polymerization rate. By maintaining optimal temperature ranges and using appropriate initiator concentrations, the process achieves high conversion rates while preventing runaway polymerization that would lead to uncontrolled molecular mass distribution. The gradual addition of monomers and control of reaction kinetics enable both high conversion and narrow molecular mass distribution.
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 solution achieves a high conversion rate of hydrophobic monomers and enhanced hydrophobicity of the paper surface, providing a compromise between high dextrin content and effective hydrophobic power, as demonstrated by the examples showing improved Cobb 60 values.
Implementation Method 1
the polymerization takes place in the presence of a free radical initiator which is a persulfate
Implementation Method 2
enhanced hydrophobicity of the paper surface
Data Source
AI summary
The invention relates to a copolymer of a dextrin and at least two hydrophobic monomers made up of styrene and at least one straight or branched acrylic C1-C4 ester. The invention also relates to the manufacturing method thereof and to the use thereof in paper coating. Said copolymer has high dextrin content (> 60 wt% relative to the weight of the dextrin and the hydrophobic monomers) so as to favor the biosourced aspect of the material, and provides very good hydrophobicity for the paper sheet.