Cellulose Ester Fiber Web for High-Pressure Pressing
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Solution Overview
Problem
Wet laid paper production faces challenges such as slow water drainage rates, energy inefficiencies in drying processes, and difficulties in maintaining tensile strength while improving air and water permeability, which limits production speed and increases operational costs.
Innovation Solution
Incorporating cellulose ester staple fibers into the wet laid process, allowing for increased pressure during water removal and improved fibrillation without compromising tensile strength, and using these fibers in combination with cellulose fibers to enhance drainage and permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If more refining energy is applied to improve web strength and toughness, then the freeness of the pulp is reduced, but the drainage rate of water from the web becomes slower
Solution Approach 1:
The patent changes the physical-chemical parameters of the pulp by introducing cellulose ester staple fibers with specific properties (fibrillation characteristics, surface properties) that alter the pulp slurry behavior, allowing for modified drainage and strength characteristics without conventional refining trade-offs
Solution Approach 2:
The patent creates a composite pulp system by combining cellulose fibers with cellulose ester staple fibers, where the different fiber types work synergistically to provide both strength and improved drainage rate simultaneously
2Productivity
If the machine line speed is increased to boost production, then more energy input to dryers is required
Solution Approach 1:
The patent performs preliminary water removal action in the press section by enabling higher press loads due to improved web strength from cellulose ester fibers, pre-drying the web before it enters the dryer section, thus reducing the energy required in dryers for higher production speeds
3Productivity
If synthetic fibers are added to improve drainage rate, then the wet tensile strength of the web drops, but the web may become difficult to process
Solution Approach 1:
The patent uses cellulose ester staple fibers with specific parameter ranges (denier, length, crimp characteristics) that optimize both drainage rate and wet tensile strength, changing the physical parameters from conventional synthetic fibers to achieve balanced performance
Solution Approach 2:
The patent maintains homogeneity by using cellulose-based ester fibers that are chemically similar to cellulose fibers, ensuring uniform web properties and processing characteristics throughout, avoiding the heterogeneity problems of conventional synthetic fiber blends
4Loss of energy
If higher pressure is applied in the press section to remove more water, then energy in drying zone is reduced, but the web may fracture or tear
Solution Approach 1:
The patent applies preliminary strengthening action by incorporating cellulose ester fibers that enhance web strength before pressing, enabling the web to withstand higher press loads without fracturing or tearing
Solution Approach 2:
The patent changes the mechanical properties of the web through cellulose ester fiber incorporation, increasing the web's load-bearing capacity and allowing higher press section pressures to be applied safely for improved water removal
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 enhances water drainage rates, reduces energy consumption in drying, and maintains or improves tensile strength, allowing for increased production speeds and improved air and water permeability without significant increases in operational costs.
Implementation Method 1
refining this mixture to prepare a refined pulp slurry or pulp stock containing fibrillated cellulose fibers
Implementation Method 2
The web layer is generally pressed through the nip of press rolls to further reduced it water content by mechanical means
Implementation Method 3
The web proceeds through a second drying zone to dry the web to the desired moisture content
Implementation Method 4
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. Specifically, a wet laid process comprising a process that allows the quantity of water removed from a web passed through press rolls is increased relative to a web made from a 100% cellulose comparative composition.