JPS6330506A - Production of improved water-soluble acrylamide polymer - Google Patents

Abstract

PURPOSE:To obtain the title high-MW polymer of excellent water solubility and improved dusting property, by drying hydrated gel particles to have a specified net polymer content, pulverizing, if required, the polymer and granulating the powder by wetting with an aqueous surfactant solution. CONSTITUTION:Acrylamide is polymerized together with, optionally, a monomer copolymerizable therewith in the presence of a radical initiator to obtain acrylamide polymer hydrated gel particles (A) of a net polymer content >=20 wt%. Component A is dried at 70-100 deg.C to form particles of a net polymer content of 50-85 wt%. These particles, if required, after being pulverized, are granulated by wetting by spraying with an aqueous solution of 500-20,000 ppm, based on the net polymer content, of a surfactant (e.g., sorbitan monooleate) to obtain the title polymer as granules of about 2 mm or smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing a water-soluble acrylamide polymer with improved dust generation and solubility.

Conventional technology Acrylamide polymers are widely used in various fields such as flocculants for wastewater treatment, sticky agents for paper making, sludge dewatering aids, and oil recovery agents, but they are generally supplied in powder form. When used in the above field, these polymer powders are dissolved in water and used in the form of an aqueous solution.

Problems to be Solved by the Invention During this dissolution operation, since the polymer powder contains fine particles, dust tends to be generated, which is often pointed out as an environmental problem. In addition, there are many cases where so-called "magic" occurs and a long dissolution time is required.

In order to avoid the above-mentioned disadvantages caused by such powder, it is sometimes supplied as a gel-like product with a polymer purity of about 20% by weight. Even in comparison to powdered products, it is difficult to make the particles thinner, so it takes a long time to dissolve. In addition, paste products with a polymer purity of 10% by weight or less are also used in some cases, but the common problem with gel-like products and paste products is that the low solid content increases transportation costs and storage costs, making them uneconomical. It is.

An object of the present invention is to provide a method for producing a water-soluble polymer composition containing as a main component an acrylamide polymer having a high molecular weight and good water solubility.

Means for solving the problems, that is, the present invention is a method for producing a water-soluble acrylamide polymer containing hydrous gel particles and a surfactant.
Hydrogel particles obtained by a conventional manufacturing method are subjected to a drying process, and after drying until the polymer content in the hydrogel particles is 50 to 85% by weight, it is pulverized or finely powdered. This is a method for producing a water-soluble acrylamide-based polymer with improved dust-emitting properties and solubility, which is characterized by carrying out humidified granulation using an aqueous surfactant solution without oxidation.

action Hereinafter, the constituent elements of the present invention will be explained together with their effects.

The present invention is a method for producing a water-soluble acrylamide polymer containing an acrylamide polymer as a main component and a small amount of a surfactant. As the monomer to be polymerized to obtain an acrylamide-based polymer, there are cases where only acrylamide is used, and cases where a monomer that can be copolymerized with this is used in combination.

Examples of copolymerizable monomers include methacrylamide, (meth)acrylic acid esters such as methyl (meth)acrylate, and ethyl (meth)acrylate, acrylic acid and its salts, methacrylic acid and its salts, Amidosulfonic acids and their salts such as 2-acrylamido-2-methylpropanesulfonic acid, dimethylaminoethyl (meth)
Examples include aminoalkyl esters and salts thereof such as acrylate and diethylaminoethyl (meth)acrylate, and aminoalkylamides and salts thereof such as dimethylaminopropylmethacrylamide.

The polymer may be anionic, cationic, or nonionic, and may be a homopolymer or a copolymer.

The polymerization method for acrylamide-based polymers is generally polymerization by normal free radical initiation, and in the case of aqueous solution polymerization, a normal radical initiator, For example, one or more of peracid initiators, redox initiators, and azo initiators may be used for polymerization. After completion of polymerization, the acrylamide polymer can be modified to have cationic amine groups by various modifications, such as hydrolysis reaction with an alkali to convert it into anionic carboxyl groups, Mannich reaction, or Hofmann decomposition reaction. Usually, the hydrous gel particles with a polymer purity of 20% by weight or more obtained by the above method are introduced into a drying process, dried, and the water-containing gel particles with a water content of 20 to 95% by weight are obtained. Use gel particles.

In the present invention, during the drying process of the hydrogel particles as described above, the acrylamide polymer has a pure content of 50 to 85% by weight, preferably 60 to 80% by weight and a water content of 50 to 15% by weight.
% by weight, preferably 40 to 20% by weight, is taken out and made into fine particles with a cutting machine or without, to a particle size of 2 mm.
The following hydrogel particles are used and subjected to humidification and granulation using an aqueous surfactant solution or a mixed solution. Drying is usually 70-1
It is carried out at about 00℃.

In this case, if the polymer pure content is less than 50% by weight, it is undesirable because the water content increases, causing caking of the powder particles and increasing product transportation costs.On the other hand, if the polymer pure content exceeds 85% by weight, dusting occurs. Also, it tends to become "sticky" when dissolved.

The reason why the particle size is 2 layers or less is to increase the dissolution rate.

In the present invention, 500 to 20,000 ppm of a surfactant is added to the hydrogel particles based on the pure polymer content. Specific examples of this surfactant include polyethylene glycol with an average molecular weight of 400 or more, and polypropylene glycol. , or nonionic surfactants such as polyoxyalkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene sorbitan fatty acid ester, sorbitan fat% ester, etc. can be mentioned. Among these, especially sorbitan monooleate, average molecular weight too
The above polyethylene glycols are preferred. As the surfactant, surfactants other than these, inorganic salts, oils, etc. can be further included. This surfactant is used to prevent caking during storage of hydrogel particles, and
If the pH is less than 00P, caking prevention is insufficient;
If it exceeds 0,000 ppm, the cost will increase and the composition will become sticky, resulting in poor fluidity and poor handling.

500 to 2% of the polymer purity of the hydrogel particles with a polymer purity of 50 to 85% by weight obtained as described above.
0000 ppm of surfactant is included. To incorporate this surfactant, it can be added as an aqueous solution or a mixed solution using an adding means such as spraying, and kneaded.In this way, the hydrogel particles absorb water and form a gel. Therefore, fine powders of about 0.1 square centimeters or less stick together and are granulated, resulting in a non-dusty granule of about 2+*+w or less as a whole.

The surface is almost coated with the surfactant, and even if it is stored under load for a long period of time, caking is prevented, there is no dust generation, and it has excellent solubility.

Example The present invention will be further explained below with reference to Examples.

Example 1 A copolymer hydrogel with a molar ratio of acrylamide and sodium acrylate of 85:15, respectively, obtained by a conventional manufacturing method (polymer purity 30% by weight, water content 70% by weight)
was introduced into a drying step and dried at a temperature of 80° C. to obtain hydrogel particles having a polymer purity of 80% by weight.

1000 g of this was placed in a rotating drum-type mixing granulator, and while the machine was being rotated, the surfactant aqueous solution was varied as shown in Table 1 and sprayed, followed by stirring and mixing for 30 minutes. These conditions and evaluation results are shown in Table 1.

Example 2 The same procedure as in Example 1 was carried out except that the polymer purity of the hydrogel taken out from the drying process of Example 1 was as shown in Table 2. Note that A was used as the surfactant.

(The following is a blank space) The symbols for the surfactant product names in Table 1 represent the following, and the evaluation was performed by the following method.

l) Surfactant Product Name A: Sorbitan Monolaurate (Product Name Rheodol SP
-LIO) B: Polyethylene glycol monooleate (trade name Emanone 4110) C: Polyoxyethylene higher alcohol ether (trade name Emulgen 707) D: Polyoxyethylene sorbitan monooleate (trade name Rheodol TW-0120) E: Polyoxy Ethylene polyoxypropylene block polymer (trade name Emulgen PP-230) F: Polyethylene glycol #40
0 G: tt #60002) Evaluation test and evaluation criteria (1) Powder test A 100 g sample was dropped from a height of 50 cm, and the light transmittance was measured on a 5 x 5 cm horizontal glass plate placed 30 cm away from the drop point. was measured. The transmittance was measured using a spectrophotometer at 0n- for 4 days.

(2) Bulk generation during dissolution 1 g of the sample was dropped into 1000 ai of still water, and then stirred at 400 rpm for 60 minutes to remove undissolved matter by 150 ai.
Filtered through mesh/wire mesh and evaluated.

(3) Fill 200g of the cake sample into a plastic bag, seal it, and
A load of cm2 was applied for one week, and the state in which the -degree granules became agglomerated due to the load was observed.

0: Not solidified at all. 0: Slightly blocky, but will disintegrate if lightly touched.

Δ: Consolidation is observed and collapses when crushed.

×...Difficult to unravel with complete blocks.

(4) Solubility: 1 g of sample was added to 1000-ml water being stirred at 40 rpm, dissolved for 90 minutes, filtered through a 150-mesh wire mesh, and undissolved particles were observed.

Effects of the Invention According to the present invention, a water-soluble polymer composition containing an acrylamide polymer as a main component that has a high molecular weight and good water solubility, which could not be obtained using conventional techniques, can be produced in a very simple and inexpensive manner. can be obtained.

Furthermore, the composition of the present invention has remarkable effects such as not causing caking even when stored under load for a long period of time, being easy to handle with no powdering when used, and not easily becoming lumpy when dissolved in water. .

Claims (1)

[Claims] In a method for producing a water-soluble acrylamide polymer containing hydrogel particles and a surfactant, hydrogel particles obtained by a normal manufacturing method are led to a drying process, and the polymer purity in the hydrogel particles is 50%. After drying to a state containing ~85% by weight, it is pulverized or, without pulverization, it is humidified and granulated using an aqueous surfactant solution. A method for producing an improved water-soluble acrylamide polymer.