JP2617410B2 - Method for producing carboxymethyl cellulose having high bulk density - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing carboxymethylcellulose having a high bulk density and excellent powder fluidity.

[0002]

2. Description of the Related Art Carboxymethyl cellulose (hereinafter referred to as C)
MC) is widely and widely used as a water-soluble polymer electrolyte as a thickener, a dispersant, a protective colloid agent, a muddy water additive for petroleum drilling, and the like. The manufacturing method is
The method is roughly divided into a solvent method and an aqueous medium method. In the solvent method, depending on the organic solvent used in the reaction and the subsequent purification step, C
The MC tends to be flocculent, and is dried, pulverized and classified, but the bulk density is apt to be low, which is not preferable because the packing material cost, the transportation freight and the warehouse storage fee are relatively high. In addition, powders having a low bulk density generally have poor fluidity and are difficult to handle. So, in order to solve these drawbacks,
Proposals have been made to make CMC into granules, with good results.

[0003] As a method of converting CMC into granules, powdered CMC is adjusted in advance to a specific water content, passed between two rolls rotating in opposite directions to form flakes, and then the flakes are formed. Invention of pulverization and classification (Japanese Patent Laid-Open No. 54-1
No. 60460). However, according to this method, it is possible to obtain CMC having a high bulk density, but it was necessary to adjust the powdered CMC to a specific water content before flake formation. In addition, there is a drawback that the process and its management are complicated, for example, a device for making flakes of CMC is required.

[0004] An invention of a method which improves this disadvantage is disclosed in Japanese Patent Application No. Hei.
No. 94973. That is, the present invention is characterized in that undried unpurified or purified CMC is passed through a kneader, and then dried, pulverized, and classified. More specifically, the amount of residual solvent in undried CMC is determined as volatile matter. A production method characterized in that the content is 30 to 70% by weight. In this method, CMC is passed through a kneader to thereby reduce CMC.
Since the gelation of MC was promoted, the bulk density was improved. However, although this method is useful, when the proportion of water in the residual solvent amount of CMC after kneading is different, a stable bulk density improvement effect cannot be sufficiently obtained, and satisfactory results have been obtained. Absent.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the bulk density is large, and the proportion of water in the amount of residual solvent in the CMC after kneading using a device to which a shearing force is applied is defined as a predetermined weight%. An object of the present invention is to provide a method for efficiently producing CMC having excellent fluidity.

[0006]

The present inventors have conducted intensive studies on the relationship between the kneading conditions of CMC and the bulk density, and as a result, the ratio of water in the residual solvent amount of CMC to a specific range. It has been found that by kneading while adjusting, the bulk density and powder fluidity can be greatly improved, and the present invention has been accomplished based on this finding. In the present invention, CMC, which is an unpurified or purified reaction product that has undergone an etherification reaction by a solvent method, is kneaded in a kneader that applies a shearing force, and water occupying in the residual solvent amount in the reaction product after kneading. 80-
After 98% by weight, preferably 85-95% by weight, the bulk density is 600-95 by drying, pulverizing and classifying.
0 g / L (gram / liter), preferably 650-8
This is a method for efficiently obtaining 50 g / L of powdered CMC.

In the method for producing CMC having a high bulk density, the amount of residual solvent in the reaction product before kneading is reduced to 30%.
It has also been found that when the content is set to about 70% by weight, the stable operation of the kneader under a shearing force and the ratio of water in the residual solvent amount of the reaction product width can be adjusted efficiently.

[0008] Each measurement value described in the present invention was performed by the following method. Residual solvent amount: left in a blow dryer at 110 ° C. for 3 hours, and was determined from the original sample weight w ₁ and the sample weight w ₂ after standing by the following equation. Ratio of water in the amount of residual solvent: 3 g of distilled water in xg of sample
0 g and 1% aqueous cellulase solution (trade name: Tricerase 2)
0, manufactured by Kyowa Hakko Kogyo Co., Ltd.) and the concentration of the organic solvent (total concentration of organic solvents used in the production of CMC) in the prepared sample left for at least 24 hours was determined by gas chromatography G.
It was measured using C-7AG (manufactured by Shimadzu Corporation) and a column packing (trade name: Porapak Q), and the value was determined by the following equation using the value.

[0009] CMC that has been etherified by the solvent method that can be used in the present invention is not particularly limited, and may be an organic solvent such as isopropyl alcohol, ethyl alcohol, methyl alcohol, benzene, or a mixture thereof. It is produced by a known reaction method such as by reacting monochloroacetic acid or the like with cellulose in the presence of an alkali using water as a reaction medium.

The bulk density of the powdery CMC efficiently obtained by the present invention is 600 to 950 g / L, preferably 650 to 8 g / L.
The reason for setting it to 50 g / L is that a material having a bulk density of less than 600 g / L can be easily obtained without using the production method of the present invention, and is preferably used when obtaining a material having a bulk density of 650 g / L or more. Although CMC of 950 g / L or more can be obtained, it is suitable for obtaining a CMC of 950 g / L or less, preferably 850 g / L or less in order to obtain efficiently. The kneading machine that can be used in the present invention is not particularly limited, and a known kneading machine can be appropriately selected and used as long as the kneading machine exerts a shearing force on the material to be kneaded, Preferably, a twin-screw kneader is provided with a temperature control device, the shaft rotation directions of which face each other when viewed from the raw material inlet, and a mechanism which collects a vaporized organic solvent or the like generated during kneading. desirable.

In the present invention, the proportion of water in the residual solvent amount of the CMC after kneading is adjusted to 80 to 98% by weight, preferably to 85 to 95% by weight. If the amount is less than 10% by weight, the effect of improving the bulk density and powder fluidity of the obtained powdered CMC cannot be sufficiently obtained, and preferably 85% by weight or more. Further, even if the proportion of water in the residual solvent is 98% by weight or more, the bulk density and powder fluidity are not significantly improved, but the CMC partially becomes paste-like and adheres to the inner wall of the kneader. For this reason, the content is preferably 95% by weight or less.
In the present invention, the amount of the organic solvent in the residual solvent of the CMC after kneading is 2 to 20% by weight, but when the organic solvent is isopropyl alcohol, it is 1% in the total organic agent.
It is preferably at least 0% by weight.

If the residual solvent content of the CMC before kneading is less than 30% by weight, an excessive load is applied to the kneading machine and it becomes difficult to stably operate the kneading machine. Is not preferable because the proportion of water in the residual volatile matter cannot be efficiently adjusted to the target range, and the effects of improving the bulk density and the powder fluidity are not good.

[0013]

EXAMPLES The present invention will be described in more detail below, but the present invention is not limited thereto.

EXAMPLE 1 Isopropyl alcohol 15 was added to a biaxial kneader having a capacity of 5 L.
26 g and 96.4 g of sodium hydroxide dissolved in 248 g of water are added. While maintaining the temperature at 25 ° C., 214 g of linter pulp is charged. While maintaining this temperature, the mixture was stirred and mixed for 90 minutes to cause an Alcer reaction. Next, a solution prepared by dissolving 108.5 g of monochloroacetic acid in 200 g of 90% isopropyl alcohol was added, and the mixture was maintained at this temperature for 30 minutes. Then, the temperature was raised to 70 ° C. over 30 minutes, and the etherification reaction was performed at this temperature for 60 minutes. Was performed. After completion of the etherification, the mixture was neutralized with acetic acid, purified twice with 10 L of 75% by weight of methyl alcohol, and dewatered with a centrifugal dehydrator to obtain CMC having a residual solvent amount of 50.3% by weight.

Further, the obtained CMC is provided with a jacket-type temperature control device, and is set to 100 rpm in a direction facing each other.
500 g was put into a twin-screw kneader (clearance between teeth and casing: 2.0 mm) rotating at, and kneaded for 10 minutes. During the kneading, a heating medium of 81 ° C. was circulated in the jacket-type temperature controller. The ratio of water to the residual solvent in the kneaded CMC was 82.3% by weight. Then this CMC
Was dried and pulverized to obtain powdered CMC.

Example 2 500 g of a CMC having a residual solvent amount of 50.8% by weight, which had been reacted, purified and drained in exactly the same formulation and procedure as in Example 1, was placed in a twin-screw kneader exactly as in Example 1. And kneaded for 10 minutes. During the kneading, a heating medium at 65 ° C. was circulated through the jacket-type temperature controller. The ratio of water to the amount of residual solvent in the CMC of the kneader was 81.2% by weight. Then this CMC
Was dried and pulverized to obtain powdered CMC.

Example 3 500 g of a CMC having a residual solvent amount of 50.1% by weight, which had been reacted, purified and drained in exactly the same formulation and procedure as in Example 1, was put into a twin-screw kneader exactly as in Example 1. And kneaded for 10 minutes. During the kneading, a heating medium at 98 ° C. was circulated through the jacket-type temperature controller. The proportion of water in the amount of residual solvent in the kneaded CMC was 96.3% by weight. Then this CMC
Was dried and pulverized to obtain powdered CMC.

Comparative Example 1 500 g of CMC having a residual solvent amount of 50.7% by weight, which had been reacted, purified and drained in exactly the same formulation and procedure as in Example 1, was put into a twin-screw kneader exactly as in Example 1. And kneaded for 10 minutes. During kneading, water at 20 ° C. was circulated in the jacket-type temperature controller. The proportion of water in the amount of residual solvent in the kneaded CMC was 67.3% by weight. Next, this CMC was dried and pulverized to obtain powdered CMC.

Comparative Example 2 500 g of CMC having a residual solvent amount of 50.2% by weight, which had been reacted, purified and drained in exactly the same formulation and procedure as in Example 1, was put into a twin-screw kneader exactly as in Example 1. And kneaded for 10 minutes. During the kneading, a heating medium at 50 ° C. was circulated through the jacket type temperature controller. The ratio of water to the amount of residual solvent in the CMC of the kneader was 70.5% by weight. Then this CMC
Was dried and pulverized to obtain powdered CMC.

Comparative Example 3 500 g of CMC having a residual solvent amount of 50.8% by weight, which had been reacted, purified and drained in exactly the same formulation and procedure as in Example 1, was put into a twin-screw kneader exactly as in Example 1. And kneaded for 10 minutes. During the kneading, a heating medium at 105 ° C. was circulated through the jacket-type temperature controller. The kneading could be carried out without any problem, but the gelatinized CMC adhered to the inner wall of the kneading machine, so it took time to remove it and the workability was poor. Kneader C
The proportion of water in the amount of residual solvent in MC was 98.5% by weight. Next, this CMC was dried and pulverized to obtain powdered CMC.

COMPARATIVE EXAMPLE 4 Biaxial kneading was carried out in exactly the same manner as in Example 1 except that CMC having a residual solvent amount of 28.0% by weight, which had been reacted and purified by the same procedure and procedure as in Example 1 and sufficiently drained, was exactly the same as in Example 1. 500 g of the kneader was put into the kneader and kneaded. However, since the load of the kneader increased sharply, the operation of the kneader was stopped.

COMPARATIVE EXAMPLE 5 CMC having a residual solvent amount of 74.0% by weight was subjected to a reaction, purification and dewatering in exactly the same formulation and procedure as in Example 1, and the same twin-screw kneader as in Example 1 was used. Was added and kneaded for 10 minutes. During the kneading, a heating medium of 81 ° C. was circulated in the jacket-type temperature controller. The ratio of water to the amount of residual solvent in the CMC of the kneader was 60.2% by weight. Next, this CMC was dried and pulverized to obtain powdered CMC.

Examples 1 to 3 and Comparative Examples 1 to 3 and 5
Table 1 shows the properties of the powdered CMC obtained in Step 1. As shown in Table 1, the CMC obtained by kneading the CMC with a kneading machine and adjusting the proportion of water in the amount of the residual solvent in the CMC after kneading to a specific range can be used. It was demonstrated that the performance was greatly improved.

[0024]

[Table 1]

* 1: Put 10 g of powdered CMC into a 50 cc measuring cylinder, drop it several times from a height of 3 cm, measure the capacity when the capacity no longer changes, and calculate the bulk density from the measured value did. * 2: Powdered CM on a 8cm diameter disk via a funnel
A value obtained by measuring the angle of a conical deposited layer formed by injecting C using a protractor.

[0026]

As described in detail above, according to the production method of the present invention, CM which has been etherified by the solvent method is used.
C is kneaded with a kneader that exerts a shearing force, and the ratio of water to the residual solvent in the reaction product after kneading is set to 80 to 98% by weight, so that the bulk density and the powder density of the powdered CMC can be easily adjusted. Fluidity can be increased, and CMC
The bulk density and the powder flowability are improved even if the powder is kept in a powder form without making it into a granular form. This eliminates the need for adjusting the pre-ground CMC to a specific moisture content and the equipment to flake the CMC, which is necessary for granulation of the CMC. Further, the amount of residual solvent in the reaction product before kneading is reduced to 30 to 7
When the content is 0% by weight, the stable operation of the kneader under shearing force and the ratio of water in the amount of the residual solvent in the reaction product can be efficiently adjusted, so that the CMC having large bulk density and large powder fluidity can be efficiently formed. The advantage of the present production method is great, for example,

Claims (2)

(57) [Claims] 1. A reaction product, which has been etherified by a solvent method, is kneaded by a device that exerts a shearing force, and the kneaded product is kneaded.
The proportion of water in the amount of residual solvent in the reaction product is 80 to 9
A method for producing carboxymethylcellulose having a high bulk density of 600 to 950 g / L, wherein the carboxymethylcellulose is obtained by drying , pulverizing and classifying after 8% by weight . 2. The amount of residual solvent in the reaction product before kneading is:
Method for producing a high <br/> carboxymethylcellulose bulk density according to 請 Motomeko 1 30 to 70 wt%.