JPS6227484A - Method of converting powdery high-molecular coagulant into easily water-soluble particulate hydrous gel - Google Patents

Abstract

PURPOSE:To convert a powdery high-molecular coagulant into an easily water- soluble particulate hydrous gel without occurrence of dust and mutual adhesion and with good workability, by continuously and simultaneously feeding a powdery high-molecular coagulant and an aq. soln. of a particular water-soluble material into a stirring tank, followed by stirring and mixing. CONSTITUTION:A powdery high-molecular coagulant is continuously and simulta neously fed, together with 0.5-10wt% aq. soln. of at last one water-soluble material selected from among polyethylene glycol, sorbitan fatty acid ester and polyoxyethylene sorbitan fatty acid ester in a weight ratio of 1:0.13-3.0, into a stirring tank. They are stirred and mixed in the tank to obtain a particu late hydrous gel having a water content of 20-80wt%. It is preferable that the hydrous gels thus formed be taken out of the stirring tank as promptly as possible in order to prevent mutual adhesion between the hydrous gels them selves.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for converting a powdered polymer flocculant into a granular hydrogel that is easy to handle.

Prior Art Most of the conventionally commercially available anionic and cationic flocculants are in powder form and have the following drawbacks.

i) Flying of fine powder The fine powder contained in powdered products, especially the fine powder of 200 mesh powder, tends to fly when it is prepared during use, and it can adhere to the face of the worker and cause damage to the mucous membranes of the eyes, lips, nose, etc. It absorbs water and becomes a jelly-like thick liquid due to its high wettability, which often causes health problems such as adhesion to the inner walls of the trachea.

In addition, the flight of fine powder will form a thin layer of powder product on the floor of the workplace during use, but if the powder product mixes with water leakage in the workplace, it will become slippery and there is a risk of falling accidents for workers. There was also sex.

ii) Powdered products are usually used by dissolving them in water, but in general, powder products tend to generate mako, and once mako occurs, it contains air inside and the outer surface is left in a moist state. This makes powder products difficult to dissolve in water, and
In order to dissolve uniformly in water in a short time of 0 minutes or less, special equipment is required, such as Japanese Patent Publication No. 5B-42204 and Japanese Patent Application Laid-open No. 5B-42204.
It was believed that a device such as that described in Publication No. 8-79525 was required.

As described above, although conventional powder products have excellent efficacy based on their water solubility and high molecular weight, they have many problems in terms of handling, and there is a need for efficient solutions to these problems. It will be done.

As a solution to this problem, flocculant manufacturers are currently trying to screen 200 mesh passes of vibration force and commercialize only relatively coarse particles, and are developing flocculants that can be easily dissolved without causing lumps. Although attempts have also been made, there is a problem of mutual adhesion (caking) of particles, and no definitive product has been obtained yet.

As a new method, Japanese Patent Application No. 59-23356 discloses a method in which a polymer gel obtained by polymerizing an aqueous solution of a water-soluble vinyl monomer is crushed, and then a vertical cutting process is performed in which the average crushing residence time is at least 3 minutes or more. This is further refined by
A method of producing powder without the generation of fines is disclosed. In this method, a polymer gel in a water-containing state is crushed and dried while maintaining a water-containing state to obtain granules that do not contain fine particles and have a sharp particle size distribution, but special equipment is required. Therefore, large capital investment is required.

Purpose of the Invention The purpose of the present invention is to provide a method for converting a powdered polymer flocculant into a fine-grained hydrogel that is easily soluble in water and has good workability without generating fine powder or mutual adhesion. shall be.

Structure of the Invention The method of the present invention comprises adding a 0.5 to 10% by weight aqueous solution of at least one water-soluble substance selected from polyethylene glycol, sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester to a powdered polymer flocculant; It is characterized in that it is continuously supplied to a stirring tank at a weight ratio of 1:0.13 to 3.00, and is stirred and mixed to produce a granular hydrogel containing water of 20 to 80% by weight.

That is, in the present invention, a powdered polymer flocculant is forcibly mixed with an aqueous solution of a specific water-soluble substance in a stirring tank, and instantaneously absorbs the aqueous solution to form a granular hydrogel. The particle size of the hydrogel can be arbitrarily selected by changing the particle size of the powdered polymer flocculant and the amount of the water solution used together with it.

A hydrogel with a large particle size can be obtained by increasing the particle size of the powdered polymer flocculant, and a hydrogel with a large particle size can also be obtained by increasing the amount of the aqueous solution. For example, by using a powdered polymer flocculant with an average particle size of 0.5 mm and changing the amount of the aqueous solution used,
．． A hydrogel having a particle size of 6 to 7.0 mm can be easily produced.

Further, the amount of water-soluble substances contained in the above aqueous solution is 0.5 to
The amount is 10% by weight, but if it is too small, the produced hydrogels will adhere to each other and become lumpy upon stirring, making it impossible to obtain the desired product. On the other hand, if the amount of the water-soluble substance is too large, it is not only uneconomical, but also the presence of the water-soluble substance may cause harmful effects during use, which is not preferable.

The concentration of water-soluble substances in the aqueous solution used in the present invention is usually 1 to 5.
Preferably, it is % by weight.

Furthermore, if the water content of the gel body is less than 20 boros, it becomes a powder, and it is impossible to obtain the hydrogel body which is the object of the present invention. cannot be formed.

Note that it is desirable that the hydrogel produced in the present invention be taken out of the stirring tank as quickly as possible; if the residence time is too long, there is a risk that the hydrogel may adhere to each other. Generally, it is desirable that the residence time of the hydrogel is 1 to 10 seconds.

Although the present invention can be effectively applied to all -M powder polymer flocculants, typical powder polymer flocculants include polyacrylamide, polyacrylamide partial hydrolyzate, and polyacrylamide. Examples include water-soluble copolymers with other vinyl monomers. Vinyl monomers copolymerized with polyacrylamide include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and dimethylaminohydroxypropyl. Cationic vinyl monomers such as acrylate, dimethylaminohydroxypropyl methacrylate, and dimethylaminoethyl acrylamide; quaternary ammonium salts of the above-mentioned cationic vinyl monomers with quaternizing agents such as alkyl halides and dialkyl sulfates;
Examples include nonionic monomers such as acrylonitrile, methacrylate, methyl acrylate, ethyl acrylate, and methacrylamide, and anionic monomers such as acrylic acid, methacrylic acid, and salts thereof.

In addition, the water-soluble substances contained in the aqueous solution used together with the powder polymer aggregation side have an average molecular weight of 300 to 50,000.
．． In particular, it is preferable to use polyethylene glycol having an average molecular weight of 1000 to 10°OOO or polyoxyethylene sorbitan fatty acid ester having an HLB of 10 or more.

Next, the present invention will be explained in more detail according to examples.
In the examples, the stirring device shown in the drawings was used.

This stirring device consists of a water gate type discharge upper plate (4) and a lower plate (5).
) is provided on the side of the cylindrical container (11), and in the lower center of the cylindrical container (1) is a drive shaft (
8) exists, and this drive shaft (8) has two types of rotation, long and short.
(21 (3) are attached above and below, and an aqueous solution storage tank (6) is provided above the stirring tank +11, and an aqueous solution such as polyethylene glycol is stored in this aqueous solution storage tank (
6) and is introduced into the cylindrical container (1) from the supply pipe (10). Note that the introduction speed of the aqueous solution is adjusted by the pulp (11), and the powder flocculant is directly charged into the cylindrical container Tll.

Example (1) Cylindrical container with a diameter of 50 cm and a height of 60 cm shown in the drawing +
11, while rotating a rotary blade (21T31 at a speed of 400 r/m), a polyacrylamide flocculant (hydrated Decomposition rate 20 mol%, average particle size 0.55 including 200 mesh pass 1%
+ am powder) was supplied from the top of the cylindrical container (1) at a rate of 20.1 kg/hr, and at the same time the aqueous solution storage tank (4
) to 5% of polyethylene glycol with a molecular weight of 6000
The aqueous solution was fed at a rate of 16.3 k+r/hr. This method was carried out continuously for 23 minutes, but the introduced polyacrylamide flocculant absorbed a 5% aqueous solution of polyethylene glycol in a short time and swelled, with an average particle size of 0.75.
mm-sized granular hydrogel was continuously obtained (yield: 1
4.1 kr).

This hydrogel has a solid content of 50.6% (water content of 49.4%).
), it contains an appropriate amount of moisture, so it has a moist appearance and does not generate dust, and is easy to handle without interparticle adhesion or caking. The solubility was almost as good as that of .

Experiments similar to those described above were conducted by changing the addition rate of the aqueous polyethylene glycol solution as shown in Table I, and gel bodies with different water contents were obtained. The results of measuring the dissolution rate of various gels in water are shown in Table 1 along with the measured values for the untreated flocculant (No. 1).

Table I *) Dissolution rate is calculated by pouring a predetermined amount of deionized water and gel into a 2000 cc beaker (an amount that can produce 200 cc of 0.5% solution of polyacrylamide), and rotating it using a 5 cm long magnetic cooler. Stir at a speed of 300 r/m, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 4 minutes after the start of stirring.
The viscosity at 0 min was measured using a BH type viscometer rotor No. 1 at 20 r/m.

As is clear from Table 1, Nos. 2 to 4 according to the present invention
While the hydrogel is completely dissolved in about 20 minutes,
The powdered product No. 1 required 30 minutes or more to dissolve. It should be noted that the powdered product of N001 temporarily caused a "stank" phenomenon during dissolution, and it took time for uniform dissolution.

Example [2] A method similar to Example [1] was carried out using polyethylene glycols having different molecular weights. The properties of each product (hydrogel) are shown in Table ■.

Table■ Note) The average diameter of the hydrogel is expressed as I.

The adhesion of the hydrogel is 30cm x 20cm.
Layered in layers with an area of m and a thickness of 25II11, 0,06
After applying a load of "kg/cm2" and leaving it at room temperature for 6 days, the adhesion between the hydrogel bodies was examined.

In both products, the hydrogel bodies do not adhere to each other,
I was able to easily massage it with my hands. No solidification (caking) phenomenon was observed.

Example [3] HLB=16°7 instead of polyethylene glycol
Hydrogels having various water contents were obtained in the same manner as in Example [1] except that polyoxyethylene sorbicun fatty acid ester (monourate) was used. The properties of the obtained hydrogels are shown in Table (1), and all of them were easy-to-handle products with good solubility in water, mutual adhesion, and no solidification phenomenon.

Table ■ Note) The adhesion of the hydrogel is 30cw x 2.
Layered in a layer with a thickness of 25I in an area of 0cm, 0.06k
After applying a load of “g/cm” and leaving it at room temperature for 7 days,
The adhesion between hydrogel bodies was investigated.

Effects of the Invention In the present invention, the powder polymer aggregate side can be easily prepared into a granular hydrogel that is easily soluble in water. The water-containing gel obtained by the present invention does not turn into fine powder and deteriorate the environment of the workplace, and even at room temperature, the water-containing gel body does not cause "stickiness" and has a
It is extremely easy to handle as it can be uniformly dissolved in water in a short time of minutes, and it is highly effective for mutual adhesion (caking) of hydrogel bodies.
It does not cause

[Brief explanation of the drawing]

The drawing is a sectional view of a stirring device used in an example of the present invention. (1) M-shaped container +21 +31 Rotating blade (4) Aqueous solution storage tank (5) Water gate type top plate (6) Water gate type outlet plate (7) Vertical drive motor (8) Drive shaft (9) Discharge port ( lO) Supply pipe (11) Pulp

Claims (1)

[Claims] A powder polymer flocculant and a 0.5 to 10% by weight aqueous solution of at least one water-soluble substance selected from polyethylene glycol, sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester are mixed in a weight ratio of 1:0.
At the same time, continuously supplied to the stirring tank at a ratio of 13 to 3.0,
A method for converting a powder flocculant into a water-soluble granular hydrogel, which comprises stirring and mixing to produce a granular hydrogel containing 20 to 80% by weight of water.