JPS62110739A - Method for granulating water-soluble cellulose derivative - Google Patents

Abstract

PURPOSE:To obtain the titled granulated product having easy dispersibility and narrow particle size distribution by extruding a mixture consisting of a powdery water-soluble cellulose deriv. which has been adjusted to have a specified volatile matter content by adding aq. soln. of a lower alcohol having a specified water content through an open net or nozzle. CONSTITUTION:A water-content of a mixture of powdery water-soluble cellulose deriv. (e.g. carboxymethyl cellulose, etc.) is adjusted to 40-90% by adding aq. soln. of lower alcohol (e.g. methanol, etc.) having >=30% water content. After mixing the mixture uniformly in a mixer, the mixture is extruded through a net having 250-1,000mum mesh or a nozzle having the same opening and the extruded product is dried. The extruded product is, if necessary, crushed or classified, and granulated product of the water-soluble cellulose deriv. is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for granulating granular water-soluble cellulose derivatives.

In general, water-soluble cellulose derivatives, such as carboxymethylcellulose (CMC), have properties that are useful as synthetic thickeners that overcome the drawbacks of natural gums, and are widely used in the textile industry, food industry, and various other chemical industries. Characteristics such as adhesion, dispersion, emulsification, and spreading are utilized.

However, despite having many excellent properties, when trying to dissolve the powder in water, so-called "mamako" occurs, which inhibits water penetration. First, it has the disadvantage that the apparent dissolution rate is very slow.

Conventionally, various methods have been proposed to improve these drawbacks. For example, there is a method of making the dispersion of particles easier by temporarily slowing down the dissolution rate on the particle surface using a chemical treatment method such as surface hydrophobization.

These methods have the disadvantage that their applications are limited by the hydrophobizing agent used.

In addition, as a method to prevent makoto in order to obtain a versatile product free from these restrictions, there is a method of adding water and granulating it, then drying and crushing it (Special Publication Publication No. 4L2111G), or a method of compression molding and then crushing it. Special Publication No. 17338, No. 1983, No. 5
8-11105111), but none of these methods can actively control the product particle size, so the one-pass yield is low, and the product is classified using a sieve and recycled many times for granulation.

Furthermore, those produced by compression molding have the disadvantage of a high rate of disintegration.

There is also a method (Japanese Patent Publication No. 44-3872) in which a cellulose derivative purified by a conventional method is extruded from a nozzle after being swollen with 20 to 70% water without drying and pulverizing. It is unsuitable for the treatment of cellulose derivatives. In other words, when water is kneaded into a powdered cellulose derivative, water permeation is inhibited due to the mako phenomenon on the surface of the water and powder as described above, making it difficult to mix the water and powder, and it is difficult to homogenize the powder. Requires large amounts of water and long mixing times.

Furthermore, when using only water, there are disadvantages such as the strong viscosity and the need to increase the extrusion pressure, and the strong stickiness of the molded products after extrusion, which causes them to stick to each other and prevent the desired shape from being obtained.

As a result of extensive research in order to improve the above drawbacks, the inventors of the tree used not only water but an aqueous solution of lower alcohol to prevent the formation of pussy on the surface of the liquid and powder. The inventors have discovered a method to achieve the desired shape by ensuring uniform mixing and reducing stickiness and stickiness, and have now provided the present invention. That is, a lower alcohol aqueous solution with a water content of 30% or more is added to a powdered water-soluble cellulose derivative to adjust the volatile content to 40 to 90%, and then mixed to be uniform, and then mixed to a concentration of 250 to 1
This is a method for granulating water-soluble cellulose derivatives, which is characterized by extruding through a 000 gm mesh or a nozzle with the same hole diameter, followed by drying, and optionally crushing and classifying.

Examples of the powdered cellulose derivatives used in the present invention include water-soluble cellulose derivatives such as carboxymethylcellulose (CMC), methylcellulose (MC), and methylhydroxyethylcellulose (MHEC).

The alcohol used in the lower alcohol aqueous solution with a water content of 30% or more used in the present invention includes a water-soluble lower alcohol such as methanol or ethanol blended with a water content of 30% or more.

The lower the water concentration of the alcohol aqueous solution, the easier it will be to extrude, but if it is lower than 30%, the disintegration rate and yield of the product will be poor.

Therefore, a water concentration of 30% or more is preferable because extrusion is easy and the disintegration rate is acceptable for practical use.

The mixer used in the present invention includes a general mixer having a kneading action.

Examples of the extrusion molding machine used in the present invention include general extrusion molding machines such as a screw set and a rotating blade type.

The diameter of the extrusion hole at this time is determined according to the required size of the granules, especially in terms of ease of extrusion and ease of dissolution.
250 to 1000 JLm, more preferably 300 to 900 JLm.

The method for granulating a water-soluble cellulose derivative according to the present invention includes adding the water 3 to the powdered water-soluble cellulose derivative.
Add a 0% or more lower alcohol aqueous solution to reduce the volatile content to 40%.
After adjusting to ~90%, mix it in a mixer to make it uniform, then extrude it from a 250 to 1000 JLIH mesh or an extrusion molding machine with a nozzle with the same hole diameter, dry it, and crush it if necessary. , is a method of classification.

When adding a lower alcohol aqueous solution with a moisture content of 30% or more, if the amount is too large, the particle shape of the extruded product may collapse,
Even if they stick to each other and dry further, they form large clumps and are difficult to form into granules.

Therefore, the amount of the lower alcohol aqueous solution having a water content of 30% or more is such that the volatile content in the mixture is 90% or less.

The product extruded from the extrusion molding machine is dried with a dryer using heated air such as an aeration dryer, a fluidized fluid dryer, or a vibration transport dryer, or with a vacuum dryer such as a double cone dryer.

Furthermore, the dried material is pulverized if necessary.

When pulverizing, it is preferable to use a pulverizing method in which a cylinder such as a roll mill has grooves and is crushed according to the size of the grooves.

Note that the water-containing alcohol aqueous solution with a low water concentration has a size that does not require pulverization.

However, if necessary, this may be classified using a sieve or the like, and those that cannot be used as a product may be recycled as granules.

The water-soluble cellulose derivative granules obtained according to the granulation method of the present invention have the following properties: 1. Granules with the desired particle size can be obtained in one pass and in high yield; 2. Particle size can be controlled during granulation; The particle size distribution of the granules can be narrowed; 3. The resulting granules have excellent fluidity and water solubility.

Examples of the present invention are shown below.

The evaluation measurement methods cited in the Examples are as follows.

l) Take 50g of the particle size distribution sample and sieve it for 10 minutes using a rotary tube shaker using 20 mesh and 90 mesh sieves,
Measure the weight of each part and give it as a percentage.

2) Disintegration rate: Percentage of particles of 90 mesh or less generated after 40g of sample is placed in a vibrating mill and vibrated for 20 minutes.

Example 1 A methanol aqueous solution with a water content of 60% is added to powdered CMC (IIS=0.8) to make the volatile content 83%, and the mixture is thoroughly mixed with a mixer.

The mixed wet material is charged into an extrusion granulator having a mesh with a mesh opening of 590 pm, and extruded into granules. This is dried in a hot air dryer for about 30 minutes to reduce the volatile content to 10% or less.

Sieve the dried material through 20 and 90 mesh sieves,
A 90 mesh granule was used as a product.

Further, 20 pieces of the product were crushed and sieved to obtain granules.

They are shown in Table 1.

The same applies to the following Examples and Comparative Examples.

Example 2 A 50% water methanol aqueous solution is added to powdered CMC (OS=0.8) to make the volatile content 88%, and the mixture is thoroughly mixed with a mixer.

The mixed paste-like material is molded using an extrusion granulator having a mesh opening of 590 ILm. Dry this in a hot air dryer for about 4
Dry for 0 minutes to reduce the volatile content to 10% or less. 2 pieces of this dried product
The mixture was sieved through 0 and 90 mesh sieves, and 20 to 90 mesh granules were obtained as a product.

Furthermore, 20 pieces of the product were crushed and sieved to obtain granules.

Example 3 An aqueous ethanol solution with a water content of 40% is added to powdered CMC (DS=OJ) to make the volatile content 81%, and the mixture is thoroughly mixed with a mixer. This wet material is molded using an extrusion granulator having a mesh having a mesh opening of 590 ILm. This granulated material is dried in a vacuum dryer for 90 minutes.
Dry at 200 torr and reduce the volatile content to 10% or less.

This dried material was sieved through 20 and 90 mesh sieves, and
A granule of 0 to 90 mesh was used as a product.

Furthermore, 20 pieces of the product were crushed and sieved to obtain granules.

Comparative Example 1 Water is added to powdered CM C (DS=0.8) so that the volatile content becomes 58%, and the mixture is mixed using an instant mixer.

This is dried in a hot air dryer for about 40 minutes to reduce the volatile content to 10% or less. Sieve through 20 and 90 mesh sieves,
The granules between 90 mesh and 90 mesh were used as a product.

Furthermore, 20 pieces of the product were crushed and sieved to obtain granules.

Comparative Example 2 Water was added to powdered CM C (DS=0.8) to reduce the volatile content to 1
8% and mix with an instant mixer. This mixture is compression molded in a roll press, ground in a grinder, and sieved through 20 and 90 mesh sieves. Particles of 20 to 90 mesh were dried with hot air to obtain granules with a volatile content of 10% or less.

Furthermore, 20 pieces of the product were crushed and sieved to obtain granules.

Comparative Example 3 A methanol aqueous solution with a water content of 25% is added to powdered CM C ([]S=0.8) to make the volatile content 64%, and the mixture is thoroughly mixed with a mixer. The wet material was charged into an extrusion granulator having a mesh size of 590 gm and granulated. This molded product
Dry in a hot air dryer for about 20 minutes to reduce the volatile content to 10% or less. Sieve with 20 and 90 mesh sieves,
The granules with 0 mesh were used as a product.

Furthermore, 20 pieces of the product were crushed and sieved to obtain granules.

Claims (1)

[Scope of Claims] A lower alcohol aqueous solution with a moisture content of 30% or more is added to a powdered water-soluble cellulose derivative to adjust the volatile content to 40-90%, and then mixed to be uniform. After extruding through an open mesh or a nozzle with the same hole diameter, it is dried and crushed if necessary.
A method for granulating water-soluble cellulose derivatives, which is characterized by classification.