JP2003212901A - Carboxymethyl cellulose and salt thereof, excellent in dispersion to water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carboxymethyl cellulose and a salt thereof. <P>SOLUTION: There are provided a carboxymethyl cellulose and a salt thereof, excellent in dispersion to water, which show 80 wt.% or more in the proportion of particles having a particle size of 177 μm or less, wherein the bulk specific gravity is 600-900 g/l, the angle of repose (as measured by the gradient method) is 55 or less, and the surface area of the whole particles (as measured by the Kr adsorption method) is 0.3 m<SP>2</SP>/g or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to carboxymethyl cellulose and salts thereof.

[0002]

2. Description of the Related Art Carboxymethyl cellulose and its salts are often used as an aqueous solution by dissolving them in water. However, conventional carboxymethyl cellulose and its salts have low dispersibility in water, and when they are poured into water, they form a dumpling. It is easy to become Mamako. When it becomes Mamako, it becomes difficult to dissolve it further. A method of blending a wetting agent or coarsening the particle size is available for preventing mamako, but there are problems that the physical properties of the aqueous solution are affected by other components and the cost of granulation is increased. Further, if the particle size is coarse, it does not easily become mamako, but there is also a problem that the solubility decreases.

[0003]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide carboxymethyl cellulose and salts thereof which are excellent in dispersibility in water when dissolved in water and hardly become mamako.

[0004]

Means for Solving the Problems As a result of earnest research by the present inventor, carboxymethyl cellulose and salts thereof having specific physical properties, particularly particle diameters in specific ranges, and having specific bulk specific gravity, surface area and repose angle, They have found that they have excellent dispersibility in water when dissolved in water, and have completed the present invention.

The present invention relates to carboxymethyl cellulose and salts thereof in which the proportion of particles having a particle size of 177 μm or less is 80% by weight or more, and the bulk specific gravity thereof is 600 to 900.
g / l, the angle of repose (measured by the tilt method) is 55 or less, and the surface area of the entire particle (measured by the Kr adsorption method) is 0.3 m ² / g or less. Carboxymethyl cellulose and salts thereof having excellent dispersibility.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The carboxymethylcellulose and salts thereof of the present invention are carboxymethylcellulose and salts thereof in which the proportion of particles having a particle size of 177 μm or less is 80% by weight or more. If the proportion of particles having a particle size of 177 μm or less is less than 80% by weight, the solubility is lowered even if the particles are dispersed in the water without being formed into a mako shape, and the granulation cost is increased. Further, when used by mixing with powder having a fine particle size, coarse particles are easily separated during transfer.

The carboxymethyl cellulose and salts thereof of the present invention have a bulk specific gravity of 600 to 900 g / l. In the present invention, the bulk specific gravity is as follows: 150 g of carboxymethyl cellulose and / or its salt is placed in a graduated cylinder,
After dropping the graduated cylinder 10 times in the longitudinal direction from a height of 5 cm, the volume of carboxymethyl cellulose and / or its salt is measured and calculated from the weight and the volume. If the bulk specific gravity is less than 600 g / l, it becomes muddy when dissolved in water, does not disperse, and the solubility decreases. Bulk specific gravity is 9
If it exceeds 00 g / l, the bulk specific gravity becomes too high and the cost increases. Further, as will be described later, when water is added, the amount of water added is increased, the drying time is lengthened, and the cost is increased.

The carboxymethyl cellulose and salts thereof of the present invention have an angle of repose of 55 or less measured by the tilt method. When the angle of repose exceeds 55, the particle shape of carboxymethyl cellulose and a salt thereof increases in a fibrous form, the dispersibility decreases when dissolved in water, and the shape becomes mama-like and the solubility decreases.

The surface area (measured by the Kr adsorption method) of the whole particles of carboxymethyl cellulose and salts thereof of the present invention is 0.3 m ² / g or less. Surface area is 0.3m ²
If it exceeds / g, the dispersibility in water will be reduced when it is dissolved in water, and mamako will be generated to lower the solubility.

The carboxymethyl cellulose and salts thereof of the present invention preferably have a water absorption coefficient of 15 or less. In the present invention, the “water absorption coefficient” is a coefficient showing the change in the water absorption rate due to the blending of carboxymethyl cellulose and its salt, and 100 g of silica sand (No. 7) is 20.
Quartz sand (No. 7) 100 for the speed of absorbing ml of water
g and carboxymethyl cellulose and its salt (abbreviated as CMC in the following formula 1) 0.200 g, the ratio of the speed of absorbing 20 ml of water, that is, the following formula 1
Indicated by. The smaller the water absorption coefficient, the smaller the water absorption rate of the particles alone when dissolving carboxymethylcellulose and its salts in water, the better the dispersibility in water, and the less likely it is that Mamako will occur, thus improving the solubility. To do.
Further, since the dispersibility in water is improved, when carboxymethyl cellulose and a salt thereof are added to a powder hair powder containing a peroxide such as a hair dye, the peroxide and the carboxy when dissolved in water are mixed. Contact with methyl cellulose and its salts is reduced, less susceptible to peroxides and improved solution viscosity stability. When the water absorption coefficient exceeds 15, the dispersibility in water when carboxymethyl cellulose and its salt are dissolved in water is lowered, and mamoko easily occurs, and the solubility is lowered. Water absorption coefficient = V / V0 Formula 1 V: Speed at which a mixture of 0.200 g of CMC and 100 g of silica sand (No. 7) absorbs 20 ml of water (seconds) V0: 100 g of silica sand (No. 7) absorbs 20 ml of water Speed (seconds)

The carboxymethylcellulose salt in the present invention is not particularly limited, and may be a mixture of these salts such as alkali metal salts such as sodium salt and potassium salt, ammonium salt and the like.

The etherification degree of the carboxymethyl cellulose and salts thereof of the present invention is preferably 0.4 or more. When the degree of etherification is less than 0.4, the solubility in water decreases when it is dissolved in water, making it difficult to use as a thickener.

The method for obtaining carboxymethyl cellulose having the above physical properties and salts thereof is not particularly limited. Preferably, it is produced by an organic solvent method using an organic solvent as a main solvent component in the step of producing carboxymethyl cellulose and a salt thereof, particularly an organic solvent method using an alcohol or a mixture of an alcohol and an aromatic hydrocarbon as the organic solvent. Is preferred. As the alcohol, it is generally preferable to use an alcohol having 1 to 4 carbon atoms. By using the organic solvent method as a method for obtaining carboxymethyl cellulose and its salt, it is easy to obtain carboxymethyl cellulose and its salt which are excellent in cost efficiency during production and have a high degree of etherification.

Further, when the organic solvent method is used as a method for obtaining the carboxymethyl cellulose and salts thereof of the present invention, it is preferable to add water (including steam). In the organic solvent method, water may be added at the time of granulation in order to improve the handling property, but the amount of water added at this time may be adjusted according to desired physical properties. Further, the amount of water used in the washing step and the water concentration in the washing solvent may be adjusted, or water may be added again for granulation after drying and re-grinding.

In general, carboxymethylcellulose and its salts produced by the organic solvent method are mainly produced by the following two steps of an alcerization reaction step and an etherification reaction step. After the mixed solution mainly consisting of the organic solvent and the sodium hydroxide aqueous solution for the alcelization reaction is put into the alcelization reaction device such as a twin-screw kneader, the pulverized pulp (cellulose) as the raw material is supplied into the mixed solution. Then, the cellulose is subjected to an alcerization reaction under an appropriate temperature condition to obtain alkali cellulose (alcerization step). A solution of monochloroacetic acid, which is an etherifying agent for the etherification reaction in the next step (using an organic solvent as a solvent), is supplied to and mixed with the alkali cellulose, and the mixture is discharged to an etherification reaction apparatus, and then discharged from the alcelization reaction step. After the discharged alkali cellulose and monochloroacetic acid are reacted under an appropriate temperature condition, the solvent is evaporated (etherification step). The obtained carboxymethyl cellulose and its salt are purified, dried and ground.

The granulation is carried out by, for example, a method of simultaneously granulating when the solvent is dried, or a method of re-granulating carboxymethyl cellulose and its salt obtained once.

The present invention will be described in more detail below with reference to test examples and examples, but the present invention is not limited thereto. Test example Test method Ratio of particles having a particle size of 177 μm or less For the carboxymethyl celluloses and salts thereof of Examples 1 to 7 and Comparative Example 1, the ratio of particles passing through a sieve having an opening of 177 μm was measured.

Dispersibility Carboxymethyl cellulose and salts thereof of Examples 1 to 7 and Comparative Example 1 (hereinafter sometimes abbreviated as CMC) 6
g and 20 g of Glauber's salt were mixed into a container, 50 g of water was added, and the mixture was stirred with a stir bar to visually check the dispersibility and subsequent solubility of carboxymethyl cellulose and its salt in the following standard. It was evaluated based on. The test and evaluation were performed by three people. ◯: The whole melted uniformly without the occurrence of mamako. X: Mamako was generated, and it took 30 minutes or more to uniformly dissolve.

Bulk Specific Gravity 150 g of carboxymethyl cellulose of Examples 1 to 7 and Comparative Example 1 and its salt were placed in a graduated cylinder and 5 cm.
The volume of carboxymethylcellulose and / or its salt was measured after dropping the graduated cylinder 10 times in the vertical direction from the height of the, and the bulk specific gravity (in g / l) was calculated from the weight and the volume.
Was calculated.

Surface Area The surface area (m ² / g) of the entire particles of the carboxymethyl celluloses of Examples 1 to 7 and Comparative Example 1 and salts thereof was measured by the Kr adsorption method.

Angle of repose The angle of repose of the carboxymethyl celluloses of Examples 1 to 7 and Comparative Example 1 and salts thereof was measured by the tilt method.

Water Absorption Coefficient For the carboxymethyl celluloses and salts thereof of Examples 1-7 and Comparative Example 1, silica sand (No. 7) was used as the water absorption coefficient.
Speed of absorbing 20 ml of water of a mixture of 100 g of silica sand (No. 7) and 0.200 g of carboxymethyl cellulose and its salt (abbreviated as CMC in the following formula 1), against the speed of 100 g absorbing 20 ml of water. The water absorption coefficient calculated by the following formula 1 = V / V0 Formula 1 V: Speed at which a mixture of 0.200 g of CMC and 100 g of silica sand (No. 7) absorbs 20 ml of water (second) V0: silica sand ( No. 7) Speed at which 100 g absorbs 20 ml of water (second)

2. Test results Table 2 shows the test results of the above (1) to (6).

[0024]

EXAMPLES Examples 1 to 7 First, carboxymethyl cellulose and its salt were produced by an organic solvent method using isopropyl alcohol (hereinafter sometimes abbreviated as IPA) as a main solvent component. That is, isopropyl alcohol (IPA) 45 is mainly contained in an alcelization reactor such as a twin-screw kneader.
5 parts by weight, 57 parts by weight of sodium hydroxide (NaOH) and 95 parts by weight of water were added to 607 parts by weight of a mixed solution for an alcerization reaction, and then 100 parts by weight of pulverized pulp (cellulose) as a raw material was mixed. Supply into solution, 2
Under a temperature condition of 0 to 25 ° C., the cellulose was subjected to an alcelization reaction for 60 minutes to give an alkali cellulose. 54 parts by weight of monochloroacetic acid (MCA), which is an etherifying agent for the etherification reaction in the next step, was added to the alkali cellulose.
97 parts by weight of an IPA solution dissolved in 43 parts by weight of PA was supplied and mixed, and the mixture was discharged to an etherification reaction apparatus, and the alkali cellulose and monochloroacetic acid discharged from the alcelization reaction step were heated to 60 ° C. under a temperature condition of 70 ° C. After reacting for minutes, the obtained reaction product was purified, dried and pulverized. The obtained mixture of carboxymethyl cellulose and its salt,
Water was added under the conditions shown in Table 1, and a mixture of carboxymethyl cellulose and its salt was moistened and granulated by a wet granulation method followed by drying and crushing.

Comparative Example 1 A mixture of carboxymethyl cellulose and its salt was produced in the same manner as in Example except that granulation was not carried out.

[0026]

EFFECTS OF THE INVENTION The carboxymethyl cellulose and its salts of the present invention have excellent dispersibility in water when dissolved in water and are less likely to become mamako. Therefore, the influence of other components such as a wetting agent on the physical properties of the aqueous solution and the particle size You do n’t have to be high,
Excellent economical efficiency such as workability and cost when used as an aqueous solution.

[Table 1]

[Table 2]

Claims (4)

[Claims] 1. Carboxymethyl cellulose and a salt thereof having a particle size of 177 μm or less and a ratio of particles of 80% by weight or more, having a bulk specific gravity of 600 to 900 g / l and an angle of repose (measured by a tilt method). Is 55 or less,
Further, carboxymethyl cellulose and a salt thereof having excellent dispersibility in water, characterized in that the surface area of the entire particles (measured by the Kr adsorption method) is 0.3 m ² / g or less. 2. The carboxymethyl cellulose and salt thereof according to claim 1, which has a water absorption coefficient of 15 or less. 3. The carboxymethyl cellulose and a salt thereof according to claim 1 or 2, which are produced by an organic solvent method using an organic solvent as a main solvent component in the step of producing carboxymethyl cellulose and a salt thereof. 4. The carboxymethyl cellulose and salt thereof according to claim 3, wherein the organic solvent is alcohol or a mixture of alcohol and aromatic hydrocarbon.