Cellulose Ester Staple Fibers in Wet Laid Sheets for Sizing Uptake
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Solution Overview
Problem
Current papermaking processes face inefficiencies in applying surface sizing agents to fibrous substrates, particularly in achieving effective sizing properties and liquid resistance in wet laid papers.
Innovation Solution
Incorporating cellulose ester staple fibers into the wet laid fibrous sheet composition, which enhances sizing composition uptake and penetration, allowing for higher concentrations of sizing agents and improved resistance to liquid penetration compared to sheets made from 100% cellulose fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface sizing agents are applied to wet laid paper, then sizing properties are improved, but the uptake and penetration of sizing composition is insufficient
Solution Approach 1:
The patent changes the physical-chemical parameters of the fibrous substrate by incorporating cellulose ester staple fibers with specific properties (hydrophobicity, surface characteristics) to enhance the uptake and penetration parameters of the sizing composition, thereby resolving the contradiction between sufficient uptake and effective sizing properties
Solution Approach 2:
The patent creates a composite fibrous material combining cellulose fibers with cellulose ester staple fibers. This composite structure provides both the porosity needed for sizing composition penetration and the hydrophobicity needed for effective sizing, simultaneously addressing both requirements
2Reliability
If higher concentrations of sizing agents are used, then sizing properties are improved, but the penetration depth is limited
Solution Approach 1:
The patent modifies the substrate parameters by adding cellulose ester staple fibers that create optimal porosity and surface energy characteristics, enabling deeper penetration of sizing composition at higher concentrations without compromising penetration depth
Solution Approach 2:
The patent utilizes the porous structure created by cellulose ester staple fibers to facilitate deeper penetration of sizing composition throughout the web, allowing high concentration sizing agents to reach deeper layers while maintaining effective sizing properties
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 use of cellulose ester staple fibers in the wet laid process enables higher sizing composition uptake and deeper penetration, resulting in improved sizing properties and liquid resistance in the final paper products.
Implementation Method 1
the cellulose ester staple fibers are present in an amount sufficient to permit the sheet to have a higher sizing composition uptake
Implementation Method 2
the cellulose ester staple fibers are present in an amount sufficient to permit the sheet to have deeper penetration of sizing at a size press
Data Source
AI summary
A process is provided for applying sizing to a wet laid fibrous sheet that comprises providing an aqueous slurry that comprises cellulose fibers and cellulose ester staple fibers; forming the wet laid fibrous sheet from the slurry; and applying an aqueous sizing composition that comprises one or more sizing agents to the wet laid fibrous sheet. In embodiments, the cellulose ester staple fibers are present in an amount sufficient to permit the sheet to have a higher sizing composition uptake and to impart higher sizing properties to the sheet, compared to a sheet formed from a 100% cellulose fiber slurry, when processed under similar conditions.