Cellulose Ether Production Viscosity via Surface Layer Removal
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Solution Overview
Problem
Current methods for producing high-viscosity cellulose ethers are limited by the maximum degree of polymerization of natural cellulose, which restricts viscosity increase, and introducing long-chain alkyl groups or crosslinking requires expensive reagents and additional facilities, altering physical properties.
Innovation Solution
Removing the surface layer of cellulose pulp rolls or bales to maintain the same degree of polymerization, thereby increasing viscosity without changing the raw material or production facility, by cutting or pulverizing the pulp into sheet-like, chip-like, or powdery forms and reacting it with an alkali metal hydroxide solution followed by etherification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the degree of polymerization of natural cellulose is increased to produce higher viscosity cellulose ether, then the viscosity of the product is improved, but the maximum degree of polymerization is limited to about 5000, restricting further viscosity increase
Solution Approach 1:
The surface layer of the pulp roll is removed before the etherification reaction to preserve high molecular weight cellulose. This preliminary action prevents degradation that would occur during storage and handling, allowing the production of high-viscosity cellulose ether without needing to increase the degree of polymerization beyond natural limits.
Solution Approach 2:
The invention changes the parameter of pulp preparation by removing the surface layer, which alters the physical state and quality of the raw material. This parameter change enables the production of high-viscosity product while maintaining the same degree of polymerization, as the surface layer removal preserves intact high-molecular-weight cellulose chains.
2Temperature
If long-chain alkyl groups are introduced or crosslinking is performed to increase viscosity, then the viscosity is improved, but expensive reagents and additional production facilities are required
Solution Approach 1:
The invention extracts and removes only the surface layer of the pulp roll that contains degraded cellulose. This selective removal allows the inner high-quality cellulose to be used for producing high-viscosity ether without requiring additional chemicals or facilities, thereby avoiding increased production costs.
Solution Approach 2:
Instead of using expensive reagents for crosslinking or long-chain alkyl introduction, the invention uses a simple and inexpensive method of removing the surface layer. This disposable approach of discarding only the degraded surface layer is more cost-effective than investing in expensive chemicals and additional production facilities.
3Temperature
If long-chain alkyl groups are introduced or crosslinking is performed, then viscosity is improved, but the physical properties of the cellulose ether may change unintentionally
Solution Approach 1:
The invention converts the harmful effect of surface layer degradation into a benefit by selectively removing it. By eliminating only the degraded surface portion, the remaining inner cellulose maintains its original physical properties while providing the desired high viscosity, thus avoiding unwanted changes that would result from chemical modification.
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 method allows for the production of high-viscosity cellulose ethers while maintaining the same degree of polymerization as the original pulp, reducing production costs and facility requirements, and ensuring consistent product quality.
Implementation Method 1
bringing the obtained cellulose pulp into contact with an alkali metal hydroxide solution to obtain alkali cellulose
Implementation Method 2
reacting the alkali cellulose with an alkylating agent to obtain a reaction product mixture
Data Source
AI summary
A method for producing a cellulose ether having a high viscosity while keeping the same degree of polymerization as that in the production of a shaped pulp without changing a raw material or production facility. More specifically, provided is a method for producing a cellulose ether including steps of: cutting or pulverizing pulp to obtain sheet-like, chip-like, or powdery cellulose pulp, wherein the pulp is formed in a form of roll whose surface layer on at least one of the circumferential side and the ends is removed, or in a form of bale whose surface layer on at least one side is removed; bringing the obtained cellulose pulp into contact with an alkali metal hydroxide solution to obtain alkali cellulose; reacting the alkali cellulose with an alkylating agent to obtain a reaction product mixture; and subjecting the reaction product mixture to purification to obtain the cellulose ether.