Refined Cotton Production Process for High Polymerization Degree
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Solution Overview
Problem
Traditional high-temperature alkali cooking and bleaching processes for producing refined cotton face challenges in achieving high viscosity and polymerization degree above 2,800 due to difficulties in controlling pulp degradation and depolymerization.
Innovation Solution
A refined cotton production process involving selective material preparation, staged cooking with specific adjuvants, and controlled bleaching using a chlorine dioxide stabilization solution to maintain high polymerization degree, including pretreatment, staged temperature control, rapid cooling, and multiple bleaching stages to inhibit depolymerization and enhance whiteness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional high-temperature alkali cooking and bleaching processes are used, then cooking efficiency is improved, but pulp degradation and depolymerization occur making it difficult to achieve high polymerization degree
Solution Approach 1:
The cooking process is divided into multiple stages with different temperature profiles. The patent uses a two-stage cooking process: first stage at 98-102°C for 60-90 minutes, then second stage at 115-125°C for 30-60 minutes. This segmentation allows controlled cooking that achieves both efficiency and high polymerization degree by avoiding excessive temperature exposure.
Solution Approach 2:
The patent applies preliminary impregnation treatment before cooking by spraying the cotton linter with a solution containing sodium hydroxide, surfactant, cyclic ketone compound, sulfur trioxide, and hydrogen peroxide. This preliminary action prepares the cotton fibers for cooking, improving alkali liquor permeability and enabling the cooking process to achieve high polymerization degree without excessive degradation.
2Productivity
If surfactants are used to enhance alkali liquor penetration, then cooking efficiency is improved, but depolymerization increases affecting high polymerization degree production
Solution Approach 1:
The patent uses a composite cooking agent containing multiple components: sodium hydroxide (1-2.5%), surfactant (0.1-0.2%), cyclic ketone compound (0.1-0.2%), sulfur trioxide (0.2-0.5%), and hydrogen peroxide (30%). This composite formulation enhances alkali liquor penetration through synergistic effects while the specific concentrations are optimized to minimize depolymerization and maintain high polymerization degree.
Solution Approach 2:
The patent optimizes the concentration parameters of each component in the cooking agent to achieve the right balance between penetration and polymerization preservation. By carefully controlling the surfactant concentration at 0.1-0.2% and combining it with other agents, the process achieves improved penetration without excessive depolymerization that would occur with higher surfactant doses alone.
3Productivity
If rapid bleaching is used to improve production efficiency, then bleaching speed is improved, but depolymerization reaches 150-300 reducing polymerization degree
Solution Approach 1:
The patent employs periodic bleaching with chlorine dioxide at controlled intervals and concentrations. The bleaching is performed in stages with the first bleaching using chlorine dioxide at controlled dosage, followed by intermediate washing and second bleaching. This periodic approach achieves thorough whitening while limiting cumulative depolymerization effects that would occur with continuous rapid bleaching.
Solution Approach 2:
The patent uses chlorine dioxide as an intermediary bleaching agent instead of traditional chlorine-based bleaching. Chlorine dioxide provides effective whitening with less depolymerization. Additionally, the patent introduces intermediate washing steps and pH control measures as intermediary actions between bleaching stages to minimize polymer chain scission while maintaining bleaching efficiency.
4Productivity
If high concentration alkali solution is used for cooking, then cooking efficiency is improved, but fiber damage and viscosity loss occur
Solution Approach 1:
The patent changes the concentration parameter of the alkali solution from traditional high concentration to a lower concentration range of 1-2.5% sodium hydroxide. This parameter change, combined with extended cooking time and multi-stage temperature control, achieves cooking efficiency without the fiber damage and viscosity loss that occur with high concentration alkali treatments.
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 achieves a polymerization degree above 2,800 by improving alkali liquor permeability, controlling depolymerization, and enhancing bleaching efficiency, resulting in high-quality refined cotton with improved whiteness and reduced production costs.
Implementation Method 1
a surfactant with a mass concentration of 0.1-0.2%
Implementation Method 2
enhance the penetration of alkali liquor in the process of cooking
Implementation Method 3
chlorine dioxide... the depolymerization often can reach 150-300
Implementation Method 4
control the depolymerization in the cooking process
Data Source
AI summary
A process for producing refined cotton with a high polymerization degree includes: a. selection of material; b. impurity removal; c. impregnation; d. pretreatment: compounding triethanolamine, sodium carbonate, copper sulfate and magnesium oxide in equal proportion to form a cooking compound adjuvant with a mass concentration of 0.2-0.5%, putting the cooking compound adjuvant into a spherical digester together with the cotton linter subjected to the impregnation treatment, heating to 70 C, stopping heating, and subjecting to idling pretreatment for 40-60 min; e. cooking; f. cooling of the spherical digester; g. formulating a chlorine dioxide bleaching stabilization solution; h. a first stage of bleaching; I. alkali treatment; J. a second stage of bleaching; K. dechlorination; and l. rolling and drying by baking.