Dry-Forming Wheel for Cellulose Blanks With Low-Stick AKD Application
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Solution Overview
Problem
Existing cellulose products formed with AKD and latex dispersions have high moisture content, leading to stickiness and adherence to mechanical components, compromising product quality and consistency.
Innovation Solution
An apparatus and method that incorporates a defibrating mill, forming wheel with discrete seats, and controlled application of AKD powder and latex, along with precise drying and pressing processes to reduce moisture and ensure uniform product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If liquid additives (AKD, latex) in water solution are applied to cellulose fiber mat, then the cellulose products gain water resistance and mechanical strength, but the high moisture content causes stickiness and adherence to mechanical components
Solution Approach 1:
The patent applies liquid additives (AKD and latex dispersions) to the cellulose fiber mat before forming and drying. This preliminary application allows the additives to penetrate and bond with the fibers during the forming process, ensuring water resistance and mechanical strength are built into the structure from the beginning, rather than requiring post-treatment that would leave excess moisture causing stickiness.
Solution Approach 2:
The patent controls the concentration of liquid additives at 5-20% and adjusts the forming temperature to 100-300°C during processing. These parameter changes optimize the balance between achieving sufficient moisture content for additive application and controlling it during drying to prevent stickiness. The temperature and concentration parameters are carefully managed to ensure additives function properly without causing harmful adherence effects.
2Productivity
If continuous forming phase with buffer loop is used, then productivity is improved, but manufacturing precision and uniformity of thickness are compromised
Solution Approach 1:
The patent divides the forming process into distinct phases: a continuous forming phase where fiber mat is continuously deposited, followed by an indexed pressing phase where discrete portions are individually pressed with precise control. This segmentation allows the continuous phase to maintain high productivity while the indexed phase ensures manufacturing precision and uniform thickness for each individual product unit.
Solution Approach 2:
The patent employs periodic indexing of the pressing operation, where the pressing mechanism operates in intermittent cycles synchronized with the continuous formation of fiber mat. This periodic action allows accumulation of a buffer loop of material to maintain continuous production flow, while each indexed pressing cycle delivers precise, uniform thickness control to individual products, resolving the contradiction between productivity and precision.
3Stability of the object's composition
If high basis weight fiber mat (300-900 gsm) is formed, then product strength and stability are improved, but the complexity of achieving uniform thickness and controlling moisture increases
Solution Approach 1:
The patent maintains continuous formation of the cellulose fiber mat at controlled basis weights of 300-900 gsm through a steady-state defibrating and depositing process. This continuity ensures uniform distribution of fibers and consistent thickness throughout the mat, achieving product stability without requiring complex intermittent adjustments. The continuous action allows precise control of fiber deposition rate and compaction to maintain uniformity across the entire mat surface.
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 effectively reduces moisture-related issues, enhancing product stability and consistency by preventing adherence and ensuring precise shaping and uniform thickness, stiffness, and surface quality.
Implementation Method 1
a defibrating mill (12) for defibrating cellulose sheets
Implementation Method 2
The discrete forming seats may be connected to a suction source to retain the loose cellulose fibers within the respective seats by suction
Implementation Method 3
a pressing wheel (32) located downstream of the fiber deposition chamber (26), rotationally driven in phase with the forming wheel (20) and configured to perform pressing of the loose cellulose fibers in the discrete forming seats
Implementation Method 4
The main application of alkyl ketene dimers (AKD) is in the sizing of paper and cardboard, as well as in the hydrophobization of cellulose fibers
Implementation Method 5
a drying device (80) located downstream of the spraying device (78) and configured to dry the array of blanks of cellulose products to a predetermined dryness level
Data Source
AI summary
An apparatus for dry forming of blanks of cellulose products including a forming wheel having an outer surface provided with a plurality of discrete forming seats, and a system for adding alkyl ketene dimer (AKD) to the blanks of cellulose products.