Method for preparing low-viscosity sodium carboxymethylcellulose

A technology of sodium carboxymethyl cellulose and low viscosity, which is applied in the field of preparation of sodium carboxymethyl cellulose with low viscosity, can solve the problems of inability to achieve ultra-low viscosity, high viscosity, limitation of sodium carboxymethyl cellulose and the like, To achieve the effect of easy operation and ultra-low product viscosity

Inactive Publication Date: 2013-08-14
CHANGSHU WEIYI TECH +1
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

This method is not easy to control, and there are potential safety hazards. If the strong oxidation method is not used, the viscosity of the product is relatively high, and the ultra-low viscosity cannot be achieved, which limits the application of sodium carboxymethyl cellulose in many fields.

Method used

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  • Method for preparing low-viscosity sodium carboxymethylcellulose

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preparation example Construction

[0015] see figure 1 . The preparation method of the low-viscosity sodium carboxymethyl cellulose described in this specific embodiment uses microcrystalline cellulose as a cellulose raw material, comprising the following steps:

[0016] 1) Premixing: pre-mix a certain amount of sodium hydroxide solution with a weight concentration of 45-52% and an ethanol solution with a weight concentration of 86-96% in a mixing container at a weight ratio of 1:1-3, and cool to 10-30°C.

[0017] 2) Feeding: Add the premixed sodium hydroxide ethanol solution into a kneader with a pair of "S" shaped shafts that rotate in opposite directions along the axis, and then add microcrystalline cellulose, microcrystalline fiber The polymerization degree of prime is 100-250. The weight ratio of microcrystalline cellulose to sodium hydroxide is controlled at 1:1-3, and the weight ratio of microcrystalline cellulose to ethanol solution is 1:1.2-5.

[0018] 3) Alkalinization of cellulose: the r...

Embodiment 1

[0026] In advance, mix 1.6 parts of sodium hydroxide solution with a weight concentration of 48% and 2.5 parts of an ethanol solution with a weight concentration of 90% and cool it below 25°C, add it to the reactor, and then add 1 part of microcrystalline cellulose to alkalize React for 40-80 minutes, alkalization temperature 15-40°C, add 1.2 parts of chloroacetic acid solution with a weight concentration of 65-78% after alkalization, etherify for 40-70 minutes, etherification temperature 25-50°C. After adding chloroacetic acid, raise the temperature to 75-80°C and continue etherification for 40-80 minutes. After etherification, discharge and neutralize the pH to 7.0-8.5, then wash and refine, recover ethanol, dry, pulverize, and sieve Produce ultra-low viscosity sodium carboxymethyl cellulose products. Viscosity (15% aqueous solution) 291mpa s, viscosity (30% aqueous solution) 16500mpa s, degree of substitution 0.962, purity 92.34%.

[0027]

Embodiment example 2

[0029] Mix 1.7 parts of sodium hydroxide solution with a weight concentration of 50% and 2.4 parts of an ethanol solution with a weight concentration of 92% in advance and cool it to below 25°C, add it to the reactor, and then put in 1 part of microcrystalline cellulose to alkalize Reaction for 40-80 minutes, alkalization temperature 15-40°C, after alkalization, add 1.3 parts of chloroacetic acid solution with a weight concentration of 65-78%, etherification for 40-70 minutes, etherification temperature 25-50°C. After adding chloroacetic acid, raise the temperature to 75-80°C and continue etherification for 40-80 minutes. After etherification, discharge and neutralize the pH to 7.0-8.5, then wash and refine, recover ethanol, dry, pulverize, and sieve Produce ultra-low viscosity sodium carboxymethyl cellulose products. Viscosity (15% aqueous solution) 283mpa s, viscosity (30% aqueous solution) 14750mpa s, degree of substitution 0.971, purity 91.76%.

[0030]

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Abstract

The invention discloses a method for preparing low-viscosity sodium carboxymethylcellulose. The method comprises the steps of alkalization of cellulose and etherification of alkali cellulose, and is characterized in that microcrystalline cellulose is taken as a cellulose raw material, wherein the average degree of polymerization of the microcrystalline cellulose ranges from 100 to 250. During preparation, the method provided by the invention takes the microcrystalline cellulose with ultra-low degree of polymerization as the raw material and does not utilize any strong oxidant; and during production, the method is safe and easy to operate; the viscosity of the product is ultralow; measured by BrookfieldLVDV-I+ type viscometer, the viscosity of the aqueous solution having the mass fraction of 15% is below 300 mpa.s, and the viscosity of the aqueous solution having the mass fraction of 30% is below 20000 mpa.s.

Description

technical field [0001] The invention relates to a preparation method of carboxymethyl cellulose sodium, in particular to a preparation method of low-viscosity carboxymethyl cellulose sodium. Background technique [0002] Microcrystalline cellulose is a pure depolymerization product of cellulose. Made from natural cellulose, it is an odorless and tasteless crystalline powder. Widely used as pharmaceutical excipients, fluidity aids, fillers, disintegrants, anti-sticking agents, etc. Calculated on dry basis, the cellulose content should be 97.0% to 102.0%. [0003] At present, the raw material commonly used in the domestic production of low-viscosity carboxymethyl cellulose sodium is wood pulp, and the method of adding hydrogen peroxide for strong oxidation is used to prepare ultra-low viscosity sodium carboxymethyl cellulose. This method is not easy to control, and there are potential safety hazards. If the strong oxidation method is not adopted, the viscosity of the produc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B11/12
Inventor 陈炳生徐斌
Owner CHANGSHU WEIYI TECH
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