Dyed Cellulose Comminution Sheet Moisture Control
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Solution Overview
Problem
Current methods for dyeing cellulose pulp comminution sheets typically involve adding dye to slurries of individual fibers or surface spraying, which do not effectively ensure that each fiber is uniformly dyed, leading to a need for a process that can dye each individual fiber without compromising the integrity of the cellulose pulp.
Innovation Solution
A process involving adjusting the moisture content of cellulose pulp comminution sheets, contacting them with aqueous dye, applying pressure to distribute the dye evenly, and heating to reduce moisture, resulting in a dyed cellulose market comminution sheet with a moisture content that prevents bleeding, allowing for the production of dyed nonwoven materials with consistent color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dye is added to slurries of individual fibers, then each fiber can be dyed, but the physical integrity of the cellulose pulp is compromised
Solution Approach 1:
The patent applies preliminary action by adjusting the moisture content of the cellulose pulp comminution sheet to a specific range (40-70% dry basis) before dyeing. This pre-conditioning creates optimal conditions for subsequent dye penetration and distribution, ensuring uniform dyeing without compromising fiber integrity. The moisture adjustment prepares the material structure in advance to accept dye evenly while maintaining strength.
Solution Approach 2:
The patent employs parameter changes by controlling the moisture content as a critical parameter during the dyeing process. By maintaining moisture within a specific range (40-70% on dry basis), the process achieves both uniform dye penetration and preservation of physical integrity. The parameter change from conventional low-moisture processing to elevated moisture processing enables the resolution of the contradiction between dye uniformity and strength retention.
2Manufacturing precision
If moisture content is increased to distribute dye evenly, then dye penetration improves, but dye bleeding occurs
Solution Approach 1:
The patent resolves this contradiction through precise parameter control of moisture content. By maintaining moisture at 40-70% on a dry basis during dyeing, the process achieves sufficient fiber swelling for uniform dye penetration while preventing excessive moisture that would cause bleeding. The parameter window is carefully defined to balance these competing requirements.
Solution Approach 2:
The patent implements feedback control by specifying a closed moisture content range (40-70% dry basis) that must be maintained throughout the dyeing process. This feedback mechanism ensures that moisture does not exceed levels that would cause bleeding while remaining high enough to allow uniform dye distribution. The process monitors and adjusts moisture to stay within this critical window.
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 ensures that each fiber is consistently dyed, maintaining the physical integrity of the cellulose pulp and preventing dye bleeding, resulting in high-quality dyed nonwoven materials with improved colorfastness.
Implementation Method 1
contacting them with aqueous dye, applying pressure to distribute the dye evenly
Implementation Method 2
heating to reduce moisture, resulting in a dyed cellulose market comminution sheet with a moisture content that prevents bleeding
Data Source
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AI summary
The present invention relates to a process for the dyeing of cellulosic fibers in the form of a comminution sheet to produce a dyed cellulose pulp comminution sheet with high moisture content. The dyed cellulose comminution sheet contains (a) a cellulose pulp comminution sheet having a cellulose content of from about 60 weight percent to about 99.9 weight percent cellulose based on the total weight of solids in the cellulose pulp comminution sheet, and a density of from about 0.3 g/cm3 to about 0.95 g/cm3; (b) a moisture content of from about 25 weight percent to about 55 weight percent, based on the total weight of the dyed cellulose comminution sheet, wherein the moisture content does not exceed bleed point of the comminution sheet; and (c) a dye.