Preparation method of cellulose ether and cellulose ether obtained in same

Abstract

The invention provides a preparation method capable of improving various performances and especially a water retention rate and light transmittance of cellulose ether. The method comprises an alkalization step, an etherification step, a desolvation step, an acid regulation step and a posttreatment step of cellulose powder, wherein the acid regulation step is as follows: adding an acrylic acid / acrylamide mixed solution accounting for 1.0 to 3.5 percent by weight of the cellulose powder and initiator accounting for 0.1 to 0.13 percent by weight of the mixed solution, stirring for 10 to 40 minutes under the condition that the temperature is not lower than 90 DEG C, determining the pH value to be 5.5 to 8.5, and then discharging the material, wherein the acrylic acid / acrylamide mixed solution consists of acrylic acid and acrylamide in a mass ratio of (3 to 9): 1, and the initiator is potassium persulfate or ammonium persulfate. The preparation method is simple and easy, the problem of poor reaction at the etherification period can be overcome by utilizing the step for systematically adjusting the pH value, the cellulose ether obtained in the method hardly contains fibers and semi-cellulose ether, so that the light transmittance, water retention property and filtration reduction effect are obviously improved. The invention also provides cellulose ether obtained by the preparation method.

Description

technical field [0001] The present invention relates to a method for preparing cellulose ether, in particular to a method for preparing cellulose ether by a solvent method, and more particularly to a preparation method capable of improving various properties of cellulose ether, especially water retention and light transmittance method. The present invention also relates to a cellulose ether obtained by the above method. Background technique [0002] Cellulose ether is the most commonly used additive in dry powder mortar. As a water retaining agent, it can prevent the moisture in the wet mortar from evaporating prematurely or being absorbed by the base layer, and ensure that the cement is fully hydrated, thereby ensuring the mechanical properties of the mortar. There are various production processes of cellulose ether, including solvent method and gas-solid method. Compared with the production of cellulose ether by gas-solid method, the production process of cellulose ether ...

AI Technical Summary

Problems solved by technology

In the production process of cellulose ether, due to equipment, process, operation and other reasons, it is very easy to have the problem of incomplete and uneven reaction of raw materials, and the incomplete and uneven reaction of raw materials will cause the product to contain raw fiber and hemicellulose ether , this part of raw fiber and hemicellulose ether will bring the following problems to the product: 1. After being dissolved in water, the solution will be turbid and the light transmittance will be poor; 2. The water retention rate is low, which will affect the workability and the full hydration of cement; 3. 1. Poor mildew resistance, easy to be corroded and deteriorated by mold; 4. High temperature resistance or high temperature stability is poor; 5. The product is fuzzy, fluffy, low specific gravity, and heavy dust, which makes it difficult for workers to pick up materials and pack them; 6. There are many tail air materials , not easy to handle, low product yield; 7, as a fluid loss control agent, the fluid loss control effect is low; 8, the excess lye in the system after the reaction is not effectively utilized; 9, the raw fiber and semi Cellulose ethers will put pressure on sewage treatment

In the existing cellulose ether preparation method, once the etherification reaction is completed, the product performance is basically determined, and the problematic products caused by incomplete and uneven reactions can only be added and diluted in a small amount in the subsequent mixing process. However, due to the continuity of chemical production, there will often be a backlog of a large number of unqualified products, coupled with more tailings, lower product yields, and pressure from sewage treatment, resulting in increased costs and difficult sales, which seriously affect the benefits of manufacturers.

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