JPH0582842B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing carboxymethylcellulose alkali metal salt (hereinafter abbreviated as CMC). Alkali metal salts include sodium, potassium, lithium, and ammonium, of which sodium is usually used. More specifically, by applying ultrasonic vibration in the CMC manufacturing process,
This is a CMC manufacturing method that has the advantage of improving the transparency of CMC products. As a synthetic glue, CMC has functions such as excellent thickening properties, suspension stability, and film-forming properties, and is used in the textile industry, food industry, paint industry, building materials, mining, civil engineering, ceramics, oil drilling,
It has a wide range of uses such as agricultural chemicals and medicine. (Prior art and its problems) There are aqueous method and solvent method as methods for producing CMC. Because the former has a low effective utilization rate of monochloroacetic acid (the ratio of the amount of etherification agent bound to cellulose to the amount of etherification agent used), in recent years the latter has been replaced by the latter, in which the arcelification reaction and etherification reaction are carried out in a water-containing organic solvent. This method is increasingly being adopted. (Proposed in Japanese Patent Publication No. 32-7491 and Journal of Industrial Chemistry, Vol. 68, No. 8, p. 1590, 1965) However, there are no methods that focus on improving the quality of CMC products obtained by these methods. Furthermore, improving transparency when the raw material base is pulp is more difficult than when using linter base.
There was also the problem that when the degree of substitution (DS) of CMC was low, it was difficult to achieve uniformity and it was difficult to improve transparency. Furthermore, the transparency of CMC obtained by these methods is at most about 0.65 in etherification and about 500 mm in transparency, and it is not possible to obtain a uniform product with high transparency, which has been required in recent years. (Means for Solving the Problems) As a result of intensive studies to improve the uniformity of CMC, that is, to increase its transparency, the present inventor found that it is possible to improve the uniformity of CMC, that is, to increase its transparency. It has been discovered that a CMC production method characterized by applying ultrasonic vibration in any of the reaction steps, preferably the alcelization reaction step and the monochloroacetic acid mixing step, is very effective in improving the uniformity of CMC. The invention was completed. In the production of CMC, CMC with a low degree of substitution, e.g. DS0.2~
In order to obtain a CMC product with a high transparency of 1.5, it is necessary to conduct a more uniform CMC reaction. In the solvent method, the raw material pulp remains fibrous throughout the manufacturing process, and therefore it is necessary to uniformly permeate the chemical solution into the solid fibers to carry out a uniform reaction. For this purpose, the raw material pulp is made into a slurry in a solvent, or the degree of crushing of the pulp is increased to make the pulp into powder. However, in the latter case, if the degree of crushing is increased too much, the transparency of the CMC product will deteriorate due to keratinization of the pulp, and separation and recovery of the CMC product will become difficult. Examples and comparative examples of the present invention are shown below. Note that percentages are based on weight. (Example) Example 1 Raw material pulp (L-5 manufactured by Jujo Paper Co., Ltd.: sulfate method pulp) was pulverized using a conventional type pulverizer (screen diameter 0.25 mm) so that there was no uncrushed pulp, and pulp with a moisture content of 1% was obtained. I got it. 100% of this 20gr
Isopropyl alcohol 426.1gr and water 35.3gr
Add the mixed solution to a separable flask and stir at 12°C for about 30 minutes. (This step is referred to as a pretreatment step) The reaction bath is sealed with nitrogen, and 27.6 g of a 31.9% aqueous sodium hydroxide solution is uniformly added thereto over 3 minutes, followed by stirring at about 15° C. for 60 minutes.
(This step is referred to as the alcelization reaction step.) Ultrasonic waves are continuously applied to the separable flask throughout this step. Specifically, an ultrasonic cleaner (Branson 07-025-220J, 230mm x 130mm x 100
mm, 60W, 1.3A resonance frequency 45KHz) to generate ultrasound. Thereafter, 28.0 gr of 32.1% monochloroacetic acid isopropyl alcohol solution is uniformly added to the reaction bath over 3 minutes, and the reaction temperature is maintained at 15-20°C. (This process is called the monochloroacetic acid mixing process.) Next, the temperature of the reaction bath was raised from 15℃ to 70℃ over 30 minutes.
Hold at 70 °C for 60 minutes. (This step is referred to as the etherification reaction step) After that, the temperature is lowered to 40° C. over 4 minutes, and 1.8 ml of a 90% acetic acid aqueous solution is added to neutralize the caustic soda. After neutralization, remove the liquid through filtration, add the filtered CMC to 1000ml of 75% methanol aqueous solution, wash, and further remove the liquid through filtration.
CMC filtered into 1000ml of 75% methanol aqueous solution
is added and the liquid is removed and filtered. Washed and filtered CMC is 90
Dry at °C to obtain the product CMC. The properties of this are the first
Shown in the table. Example 2 CMC is obtained in the same manner as in Example 1, but the only step in which ultrasonic waves are applied is the monochloroacetic acid mixing step. The properties of this are shown in Table 1. Example 3 CMC is obtained in the same manner as in Example 1, but when the step of adding ultrasound is the alcelization reaction and monochloroacetic acid mixing step, the properties are shown in Table 1. Example 4 CMC is obtained in the same manner as in Example 1, but the steps in which ultrasonic waves are applied are the alcelization reaction step, the monochloroacetic acid mixing step, and the etherification reaction step. The properties of this are shown in Table 1. Comparative Example 1 When a product CMC was obtained in the same manner as in Example 1, the properties are shown in Table 1.

【table】

[Table] (Effects of the Invention) It was found that the CMC obtained by the CMC manufacturing method of the present invention has much better transparency than the CMC obtained by the conventional method. Therefore, transparency is required in pharmaceuticals, agrochemicals, mining,
We believe that it will be useful in a wide range of fields such as civil engineering, building materials, and food.

Claims (1)

[Claims] 1. A method for producing a carboxymethyl cellulose alkali metal salt, which comprises applying ultrasonic vibration in any of the alcelization reaction step, the monochloroacetic acid mixing step, or the etherification reaction step of the carboxymethyl cellulose alkali metal salt production process.