Co-refining Cellulose and Ester Fibers for Wet Laid Paper Drainage
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Solution Overview
Problem
Wet laid paper production faces challenges in increasing drainage rates without reducing wet tensile strength, energy efficiency in drying processes, and maintaining desired properties like air and water permeability, while also considering environmental sustainability and cost-effectiveness.
Innovation Solution
A process involving the co-refining of cellulose fibers with cellulose ester staple fibers, which enhances drainage rates, maintains dry tensile strength, and improves air and water permeability, while allowing for reduced energy consumption and increased production speed without significant capital expenditure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If more refining energy is applied to increase web strength and toughness, then the wet tensile strength is improved, but the freeness of the pulp is reduced resulting in a slower drainage rate
Solution Approach 1:
The patent applies parameter changes by introducing cellulose ester fibers with specific properties (degree of substitution, fiber length distribution, fineness) to modify the pulp's drainage characteristics. By controlling the degree of substitution (1.5-3.0) and fiber dimensions, the invention achieves improved drainage rates while maintaining web strength, resolving the contradiction between refining energy input and drainage performance
Solution Approach 2:
The patent uses composite materials by combining cellulose fibers with cellulose ester fibers in a controlled ratio (5-50 wt% cellulose ester). This composite approach allows the cellulose ester component to provide drainage enhancement while the cellulose matrix maintains structural integrity, simultaneously improving both drainage rate and web strength
2Productivity
If synthetic fibers are added to improve drainage rate, then the drainage rate is improved, but the web tensile strength drops significantly making the web difficult to process
Solution Approach 1:
The patent specifies precise parameter ranges for cellulose ester fibers including degree of substitution (1.5-3.0), fiber length (0.5-5.0 mm), and fineness (0.5-3.0 microns) to optimize the balance between drainage enhancement and strength maintenance. These controlled parameter changes prevent the excessive strength loss that occurs with conventional synthetic fiber additions
Solution Approach 2:
The patent applies local quality by using cellulose ester fibers with specific local properties (controlled degree of substitution, specific fiber morphology) that are different from conventional synthetic fibers. The cellulose ester component provides localized drainage enhancement while maintaining compatibility with the cellulose matrix, preserving overall web strength
3Productivity
If machine line speed is increased to increase production, then productivity is improved, but additional dryer energy input is required
Solution Approach 1:
The patent modifies the physical parameters of the pulp stock by adding cellulose ester fibers that change the drainage characteristics and web formation properties. This allows the system to achieve better drainage at higher speeds, reducing the energy burden on the drying section and enabling increased production without proportional energy increases
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 effectively increases drainage rates, maintains or improves tensile strength, and enhances permeability, thereby optimizing energy use and production efficiency while being environmentally sustainable.
Implementation Method 1
enhances drainage rates
Implementation Method 2
refining this mixture to prepare a refined pulp slurry or pulp stock containing fibrillated cellulose fibers
Implementation Method 3
Water is typically removed through a combination of gravity and vacuum
Implementation Method 4
enters a drying zone for further removal of moisture from the web by the application of thermal energy
Data Source
AI summary
The present invention provides compositions comprising cellulose fibers and cellulose ester fibers and wet laid articles made from the compositions, as well as wet laid processes to produce these compositions. More specifically, the present invention provided compositions comprising cellulose fibers and cellulose acetate fibers and wet laid articles made from these compositions as well as wet laid processes to produce these compositions. The present invention also relates to developing a composition, process, wet laid product, or articles exhibiting any one of many desired benefits.