JPH08165303A - Apparatus and process for producing aqueous-gel crosslinked polymer particle - Google Patents

Abstract

PURPOSE: To produce a aqueous-gel crossilinked polymer particles without forming coarse particles by locally cutting an aqueous-gel crosslinked polymer with impellers freely rotatably arranged in a reactor without preventing the flow. CONSTITUTION: An aqueous solution containing a monomer and a crosslinking agent is fed into a reactor 1 and polymerized to obtain an aqueous crosslinked polymer. This polymer is then locally cut with impellers 2a, 2b, 2c, 2d and 2e freely rotatably arranged in the reactor 1 without preventing the flow to obtain the purpose polymer particles. The term 'locally cutting' as used herein means effecting only the cutting of the polymer without actively carrying it in the reactor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for producing a polymer, and more particularly, to an apparatus and a method for producing hydrogel crosslinked polymer particles.

[0002]

2. Description of the Related Art One of the methods for producing a hydrogel crosslinked polymer is a thin film polymerization method in which a monomer as a raw material is polymerized in a thin film on a moving belt. The polymer obtained by this method needs to be dried depending on the application, and in order to be dried efficiently, it is necessary to increase the surface area by mechanically segmenting the hydrogel crosslinked polymer. . Since the polymer obtained by the thin film polymerization method is in the form of a thin film, a step of subdividing the polymer obtained in the polymerization step (subdivision step) is necessary in addition to the polymerization step. Thus, the thin film polymerization method usually requires two steps before drying.

On the other hand, the polymerization process and the subdivision process are
As a method which can be carried out in the step, a reverse phase suspension polymerization method in which an aqueous solution of a monomer as a raw material is dispersed in an organic solvent for polymerization, and a kneader as disclosed in Japanese Patent Publication No. 2-19122. A method using a kneader is known.
The method disclosed in Japanese Examined Patent Publication No. 2-19122 is obtained by polymerizing an acrylate monomer (aqueous solution) in a double-arm kneader and producing a polymer produced as the polymerization proceeds.
It is made into fine particles while crushing with a stirring blade provided in the kneader.

However, in the reverse phase suspension polymerization method, various problems occur because a large amount of organic solvent is handled. Further, in the method using the kneader, the stirring blade provided in the kneader usually has a function of transporting the substance in the kneader, and thus a large driving device is required to drive the stirring blade. Therefore, the device becomes large and the manufacturing cost is high. Further, when polymerizing a substance having viscosity, a large load is applied to the stirring blade, and the rotation of the stirring blade may be stopped. Furthermore, due to the internal structure of the kneader, the cutting force may not act uniformly on the generated gel, and some gels may not be scratched by the stirring blades at the initial stage of polymerization, resulting in coarse particles. Gel is also produced at the same time.

[0005]

The problem to be solved by the present invention is to simplify the apparatus for producing hydrogel crosslinked polymer particles. Another problem to be solved by the present invention is to shorten the drying time of the crosslinked gel polymer.

Still another problem to be solved by the present invention is to prevent formation of coarse particles when polymerizing a crosslinked gel polymer.

[0007]

The apparatus for producing hydrogel-like crosslinked polymer particles according to the present invention is a method for polymerizing a monomer by aqueous solution polymerization in the presence of a crosslinking agent to obtain a hydrogel-like crosslinked polymer. A reaction container for accommodating the water-containing gel-like cross-linked polymer, a rotating shaft rotatably arranged in the reaction container, and a plurality of blades for making the polymer fine particles. I have it. The blades are supported on the rotating shaft so as to locally cut the water-containing gel-like cross-linked polymer and allow the water-containing gel-like cross-linked polymer to flow in the direction along the rotation axis. Shape or arrangement.

It is preferable that the plurality of blades are formed of a plate-shaped member, and that a plane in a direction intersecting the rotation axis is substantially perpendicular to the rotation axis. It is preferable that the plurality of blades are arranged such that two adjacent blades do not overlap each other when viewed from the direction along the rotation axis. The plurality of blades may have a strip shape, and two blades adjacent to each other may be attached in opposite directions with respect to the rotation axis.

The plurality of blades may have a fan shape, and two blades adjacent to each other may be installed in opposite directions with respect to the rotation axis. The method for producing a hydrogel-like crosslinked polymer particle according to the present invention, the monomer is polymerized by aqueous solution polymerization in the presence of a crosslinking agent to obtain a hydrogel-like crosslinked polymer,
This is a method of making this polymer into fine particles, and includes a material supplying step, a reaction step, and a cutting step. The material supplying step is a step of supplying an aqueous solution containing a monomer and a crosslinking agent to the reaction vessel. The reaction step is a step of polymerizing a monomer and a crosslinking agent to obtain a hydrogel crosslinked polymer. The cutting step is a step of locally cutting the water-containing gel-like cross-linked polymer without impeding the flow in the reaction vessel by means of a blade rotatably arranged in the reaction vessel.

The monomer may be at least one selected from the group consisting of acrylic acid or methacrylic acid neutralized with an alkali metal base or ammonium base in an amount of 50 to 100 mol%, acrylamide and methacrylamide. In the material supplying step, the weight concentration M% of the monomer and the molar concentration X of the crosslinking agent with respect to the monomer are
It is preferable that the step is a step of supplying the monomer and the crosslinking agent so that mol% satisfies the relational expression of M ≧ −60X + 42.

[0011]

In the apparatus for producing hydrogel-like crosslinked polymer particles according to the present invention, an aqueous solution containing a monomer and a crosslinking agent is supplied into a reaction vessel. In this state, the rotary shaft in the reaction container is rotated. In the reaction vessel, the monomer is polymerized by aqueous solution polymerization to form a hydrogel crosslinked polymer. On the other hand, the rotary shaft is provided with a plurality of blades, and the hydrogel crosslinked polymer obtained as described above is locally cut by the plurality of blades. In the present invention, "locally cut" indicates that in the reaction vessel, the hydrogel-like crosslinked polymer is not positively transported and only the hydrogel-like crosslinked polymer is cut. There is.

In the course of cutting the polymer, there are polymer particles having a large particle size that have not been sufficiently cut and polymer particles having a small particle size that have already been sufficiently cut. Particularly, in the case of a hydrous gel-like cross-linked polymer, the tackiness decreases as the polymerization proceeds, and polymer particles having a small particle size are likely to be formed due to the cutting action. At this time, the smaller the particle size of the polymer particles is, the less resistant they are to the resistance in the reaction system. Therefore, the small particle size of the polymer particles easily moves to the lower part of the reaction vessel due to its own weight. As a result, as the polymer particles are made finer, the polymer particles having a smaller particle size are accumulated below the reaction container, while the polymer particles having a larger particle size are gathered above the reaction container. When such an operation is repeated, the blade has a shape and an arrangement that does not hinder the fluidization of the polymer particles, so that the polymer particles circulate in the reaction vessel and are cut during the process. Progression of finer particles.

In this way, the polymer in the reaction vessel can be uniformly made into fine particles. Further, since the plurality of blades only locally cut the polymer, the load of the polymer is small, and thus the rotational driving force may be small. Furthermore, since the hydrogel crosslinked polymer flows due to its own property, that is, the property that the tackiness decreases as the polymerization progresses, it is not necessary to separately install a device and the device can be downsized. Is.

When the plurality of blades are formed of a plate-like member and the plane in the direction intersecting the rotation axis is substantially perpendicular to the rotation axis, the load of the polymer is smaller. Become. Therefore, the size of the device can be reduced.
When the two adjacent blades are arranged so as not to overlap each other when viewed from the direction along the rotation axis, the plurality of blades flow in the direction along the rotation axis of the hydrogel crosslinked polymer. The effect of not hindering is increased. Therefore, the synergistic effect with the effect that the plurality of blades locally cut the water-containing gel-like cross-linked polymer makes it possible to make uniform fine particles and downsize the apparatus.

When the plurality of blades are strip-shaped and the adjoining two blades are installed in opposite directions to the rotation axis, the hydrogel crosslinked polymer flows in the direction along the rotation axis. The effect of not hindering is increased. Therefore, the synergistic effect with the effect that the plurality of blades locally cut the water-containing gel-like cross-linked polymer makes it possible to make uniform fine particles and downsize the apparatus.

When the plurality of blades are fan-shaped and the adjoining directions of two adjacent blades are opposite to each other, the flow of the water-containing gel-like crosslinked polymer is not obstructed and a uniform fine particle is formed as described above. It is possible to make particles and to downsize the device. In the method for producing hydrogel-like crosslinked polymer particles according to the present invention, first, an aqueous solution containing a monomer and a crosslinking agent is supplied into the reaction vessel in the material supplying step. In the next polymerization step, the monomers are polymerized by aqueous solution polymerization in the reaction vessel to form a hydrogel-like polymer, and at the same time, a cross-linking agent forms a crosslinked structure in the hydrogel-like polymer to form a hydrogel-like crosslink. It becomes a polymer. Furthermore, in the cutting step, the hydrogel-like crosslinked polymer is locally cut without being impeded by the rotatably arranged blades to flow in the reaction vessel. The polymer in the reaction vessel is efficiently and uniformly made into fine particles. At this time, the water-containing gel-like crosslinked polymer flows due to its own property, that is, the property that the tackiness decreases as the polymerization progresses, so there is no need to install a separate device for transportation, and a simple device is used. As a result, hydrogel-like crosslinked polymer particles can be obtained.

Even when the above-mentioned monomer is at least one selected from the group consisting of acrylic acid or methacrylic acid neutralized with an alkali metal base or ammonium base in an amount of 50 to 100 mol%, acrylamide and methacrylamide, it is possible to obtain Since the obtained water-containing gel-like crosslinked polymer is efficiently and uniformly made into fine particles, it is difficult to obtain coarse particles.

In the material supplying step, the weight concentration M% of the monomer and the molar concentration Xm of the crosslinking agent with respect to the monomer are
When the ol% is the step of supplying the monomer and the cross-linking agent so as to satisfy the relational expression of M ≧ −60X + 42, the hydrous gel-like cross-linked polymer produced by the polymerization is a plurality of The blades easily make fine particles, and coarse particles are less likely to be generated. In addition, since the particles are made into fine particles and have a large surface area, the heat of reaction due to the polymerization is effectively removed by the evaporation of water from the surface of these particles. Therefore, the control of the polymerization temperature is extremely easy, and it is possible to increase the polymerization rate to increase the productivity. Furthermore, since the hydrogel-like crosslinked polymer particles obtained by the present invention have a large surface area,
It can be easily dried in a short time by hot air drying or the like.

[0019]

【Example】

<Manufacturing Device> As shown in FIG. 1, the manufacturing device for the water-containing gelled crosslinked polymer particles according to the embodiment of the present invention comprises a reaction container 1
, The rotary shaft 3, and the plurality of blades 2a, 2b, 2c, 2d,
2e and the motor 4 for driving the rotating shaft 3 are provided.

The reaction vessel 1 is formed in a vertical cylindrical shape and has an open top. A lid 1 a is arranged at the upper opening of the reaction container 1. On the bottom of the reaction vessel 1 is a rotating shaft 3
Is formed with a hole 1b, and a seal member 5 is provided in the hole 1b. The rotating shaft 3 is arranged so as to extend in the vertical direction inside the reaction container 1, and its lower end penetrates the bottom of the reaction container 1 and is connected to the motor 4.

A plurality of blades 2a, 2b, 2c, 2d, 2e
2 has a fan shape as shown in FIG. 2, and the mounting directions of the two blades vertically adjacent to each other with respect to the rotary shaft 3 are opposite. Further, the blades 2a, 2b, 2c, 2d, 2e are formed of plate-shaped members as shown in FIG. 1, and the plane of the blades in the direction intersecting with the rotation axis 3 is substantially relative to the rotation axis 3. It is installed so that it is vertical. Therefore, the blades 2a, 2b, 2c, 2d, 2e locally cut the water-containing gel-like crosslinked polymer in the reaction vessel 1.

<Manufacturing Method> Next, the function of this embodiment will be described by explaining the method of manufacturing the hydrogel crosslinked polymer particles. Material Supply Step The monomer and the cross-linking agent used in this example form a cross-linked structure by aqueous solution polymerization, and become a hydrogel cross-linked polymer. The crosslinked structure is obtained by copolymerization of a monomer mixture containing the above monomer and a crosslinking agent (crosslinkable monomer having two or more polymerizable double bonds in the molecule) as main components. Further, in the presence of a hydrophilic polymer such as starch, cellulose, polyvinyl alcohol, etc., a crosslinked structure may be formed by polymerizing the monomer mixture by aqueous solution polymerization and simultaneously forming a graft bond or a complex. .

Examples of the monomer include acrylic acid, methacrylic acid, acrylic acid or methacrylic acid neutralized with an alkali metal base or ammonium base in an amount of 50 to 100 mol%, acrylamide, and methacrylamide. You may use 2 or more types of these. If necessary, a water-soluble monomer such as acrylonitrile, 2-hydroxyethyl (meth) acrylate, methyl acrylate, maleic acid or the like may be added to this monomer as a subcomponent.

As the cross-linking agent, ethylene glycol, diethylene glycol, triethylene glycol,
Propylene glycol, 1,4-butanediol, 1,
5-pentanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane or pentaerythritol diacrylate or dimethacrylate, polyethylene glycol diacrylate,
Tetraaryloxyethane, trimethylolpropane, pentaerythritol triacrylate or trimethacrylate, pentaerythritol tetraacrylate or tetramethacrylate, N, N-methylenebisacrylamide, N, N-methylenebismethacrylamide, triallyl isocyanurate, etc. Two or more of these may be used.

The mixing ratio of the monomer and the cross-linking agent is preferably 0.001 with respect to 100 mol% of the monomer.
~ 5 mol%, more preferably 0.01-0.5 mol%
Is. When the amount of the cross-linking agent used is less than 0.001%, the resulting hydrogel polymer is soft and sticky, and even when subjected to mechanical cutting force, it sticks to each other and becomes a lump, resulting in fragmentation. It is hard to be done. If it is used in an amount of more than 5 mol%, the water absorption of the obtained crosslinked polymer will be low.

The initial concentration of the aqueous solution of the monomer mixture is set so that the weight concentration of the monomer with respect to the aqueous solution is M% and the molar concentration of the cross-linking agent with respect to the monomer is X mol%, and the following relational expression is satisfied. Is preferred. Relational expression: M ≧ −60X + 42 If the weight concentration M of the monomer is within this range, the hydrogel-like cross-linked polymer produced as the polymerization proceeds is easily fragmented by the cutting force, and the polymerization The temperature can be easily adjusted.

In the present example, known water-soluble radical polymerization initiators for radical aqueous solution polymerization of the monomer mixture can be used. For example, persulfate, hydrogen peroxide,
Examples thereof include water-soluble azo compounds, which may be used alone or in combination with sulfites, hydrogen sulfites, thiosulfates, L-ascorbates, ferrous salts and the like. You may use it as a system initiator.

Reaction Step In the reaction step, the monomers are polymerized by aqueous solution polymerization in the reaction vessel to form a hydrogel polymer and a crosslinking agent forms a crosslinked structure in the hydrogel polymer to form a hydrogel. It becomes a gelled crosslinked polymer. Cutting process In the cutting process, the rotating shaft 3 is rotated by the motor 4,
The blades 2a to 2e are rotated. Here, since the upper surface of the blade is orthogonal to the rotation axis 3, the hydrogel cross-linked polymer obtained in the reaction vessel 1 is not substantially conveyed in the rotation axis direction by the blade. To cut locally.

Here, it is preferable that the peripheral speed of the blade is set within a range of 0.2 m / s to 5.0 m / s, and a range of 1.0 m / s to 1.6 m / s. It is more preferable to set the value within. If the number of revolutions is less than 0.2 m / s, the substance during polymerization undergoes cutting force,
It adheres to each other to form a lump, and it is difficult to form fine particles. On the other hand, when it is more than 5.0 m / s, a large load is mechanically applied to the hydrogel crosslinked polymer, which is not preferable.

Here, in the course of cutting, the water-containing gel-like crosslinked polymer becomes less sticky as the polymerization progresses, and is susceptible to cutting action to form polymer particles having a small particle size. At this time, the smaller the particle size of the polymer particles is, the less resistant they are to the resistance in the reaction system. As a result, as the polymer particles become finer, the polymer particles having a smaller particle size are accumulated below the reaction container 1, while the polymer particles having a larger particle size are gathered above the reaction container 1. When such an operation is repeated, the blades are fan-shaped and the adjoining directions of two adjacent blades are opposite, so that the flow of particles in the direction along the rotation axis 3 is not hindered. . Therefore, the particles circulate in the reaction vessel 1 and are further cut in the middle of the process to form fine particles.

By carrying out the aqueous solution polymerization in this manner, a hydrogel polymer having a particle form and having a cross-linking structure in each particle is obtained, and it varies depending on the reaction conditions.
Particles having a particle size of 1 cm or less can usually be obtained. The obtained water-containing gelled crosslinked polymer particles not only have little mutual adhesion, but also have very good mold releasability from the inner wall and blades in the reaction vessel, and have good fluidity, so that the reaction vessel 1 can be easily removed. You can take it out.

The water-containing gel-like crosslinked polymer particles obtained by the polymerization method of this example are used as they are as an absorbent, a water retention agent,
Although it can be used as an ion exchange resin, an adsorbent, or the like, it is preferably dried to remove water for handling. The crosslinked polymer obtained by drying the water-containing gel-like crosslinked polymer particles is coarse particles as it is, or pulverized into a powder,
It is applied to a wide range of applications such as sanitary napkins, sanitary absorbents such as disposable diapers, and water retention agents and dehydrating agents in the fields of agriculture and horticulture and civil engineering. At this time, in this example, the hydrous gel-like crosslinked polymer particles are uniformly finely divided, and since the surface area is increased, the drying time can be shortened,
A uniform dried product can be obtained.

[Modification] (a) The shape and number of the plurality of blades are not limited to those in the above embodiment. The shape of the blade, if not impeding the flow in the direction along the rotation axis of the hydrogel crosslinked polymer, for example,
The blade itself may have holes for allowing the hydrogel crosslinked polymer to flow in the direction along the rotation axis. Further, as shown in FIG. 3, it may have a strip shape. In this case, it is preferable to reverse the mounting direction as shown in the figure.

(B) Although a vertical reaction vessel is used in the above-mentioned embodiment, it can be similarly applied to a horizontal reaction vessel. Further, in the above-mentioned embodiment, the device was used as a batch type,
The same can be applied to a continuous device. (C) In the above-mentioned embodiment, one rotary shaft is arranged in the reaction vessel, but a plurality of rotary shafts may be provided.

(D) In the above embodiment, two adjacent blades were mounted on the rotary shaft at an angular interval of 180 ° from each other. The blade locally cuts the hydrogel crosslinked polymer,
In addition, the angular interval is not limited to 180 ° as long as it does not hinder the flow of the hydrogel crosslinked polymer in the direction along the rotation axis. <Experimental example> Below, the concrete experimental example and comparative experimental example of the superposition | polymerization method using the apparatus of this Example are shown. Further, the monomer concentration is a percentage of the weight of the monomer and the crosslinking agent with respect to the weight of the aqueous monomer solution, and the crosslinking agent concentration is a percentage of the mole number of the crosslinking agent with respect to the mole number of the monomer.

(Experimental Example 1) -Polymerization Apparatus-The uniaxial vertical cylindrical stirring polymerization apparatus shown in FIG. 1 was used. The reaction vessel is a polypropylene cylinder having a bottom diameter of 80 mm and a depth of 120 mm. The blade is SUS304
It is made of a fan shape with a thickness of 1 mm, a radius of 39 mm and a central angle of 90 degrees, and its fan surface is horizontal. The rotating shaft has a diameter of 8 m
It is made of SUS304, and is located at a position 5 mm from the bottom.
It has one blade. There are four blades at an interval of 20 mm above this blade, and the mounting directions of the respective blades with respect to the rotation axis are opposite (having an angle of 180 degrees with the adjacent blades).

*** To the above polymerization apparatus, a monomer aqueous solution containing 20.6 parts of acrylic acid, 80.9 parts of sodium acrylate, 0.34 parts of trimethylolpropane triacrylate, and 164 parts of water was supplied. (Monomer concentration 38% by weight, crosslinking agent concentration 0.1 mol%). Nitrogen gas was blown into this aqueous solution to replace the inside of the reaction system with nitrogen. Further, the reaction vessel was immersed in a water bath at 30 ° C. and heated to bring the reaction system to about 30 ° C.

Next, this rotary shaft was rotated at 370 rpm, and 1.38 parts of a 10% by weight aqueous solution of sodium persulfate was added.
And 0.57 part of a 1% by weight aqueous solution of L-ascorbic acid were added. Polymerization starts 20 seconds after the addition, and the monomer forms a hydrogel-like crosslinked polymer as the polymerization progresses, and the hydrogel-like crosslinked polymer is gradually subdivided by the blades rotating with the rotating shaft. It was The stirring was stopped 30 minutes after the initiation of the polymerization, and the finely divided hydrogel-like crosslinked polymer was discharged. At this time, there was no deposit on the polymerization container, the rotating shaft, and the blade, and the polymer could be easily discharged simply by tilting the reaction container. The obtained hydrogel crosslinked polymer did not contain a polymer having a diameter of 10 mm or more and was subdivided into a diameter of about 2 mm. This polymer is uniformly placed on a wire mesh and heated at 150 ° C.
It was allowed to stand and dry for 30 minutes with the hot air dryer. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 2) The same operation as in Experimental Example 1 was carried out using the same apparatus as in Experimental Example 1 except that the rotary shaft was rotated at 250 rpm. The hydrogel crosslinked polymer obtained in the same process as in Experimental Example 1 did not contain a polymer having a diameter of 10 mm or more, and was subdivided into a diameter of about 2 mm. This polymer was uniformly placed on a wire net and was allowed to stand and dry for 30 minutes in a hot air dryer at 150 ° C. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 3) 80 from the lowermost blade upward
The same operation was performed using the same device as in Experimental Example 1 except that one blade was present at an interval of mm. The hydrogel cross-linked polymer obtained in the same process as in Experimental Example 1 had a thickness of 10 mm.
It did not contain a polymer having the above diameter and was subdivided into diameters of about 2 mm. The polymer is evenly placed on the wire mesh and
It was allowed to stand and dry for 30 minutes in a hot air dryer at 0 ° C. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 4) The shape of the blade was 8 mm × 40 m.
The same device as in Experimental Example 1 was used except that the rectangle was m.
The same operation was performed. The hydrogel crosslinked polymer obtained in the same process as in Experimental Example 1 did not contain a polymer having a diameter of 10 mm or more, and was subdivided into a diameter of about 2 mm. This polymer was evenly placed on the wire mesh and dried with a hot air dryer at 150 ° C.
It was left to dry for 0 minutes. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 5) Except that the extending direction of the blade has an angle of 120 degrees with the extending direction of the adjacent blade,
The same operation was performed using the same device as in Experimental Example 1. The hydrogel-like crosslinked polymer obtained in the same process as in Experimental Example 1 was 1
It did not contain a polymer having a diameter of 0 mm or more and was subdivided into a diameter of about 2 mm. This polymer was uniformly placed on a wire net and was allowed to stand and dry for 30 minutes in a hot air dryer at 150 ° C. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 6) 56.3 parts of acrylamide, 31.9 parts of sodium acrylate, and 2.48 parts of sodium salt of sulfoethyl methacrylate were added to the uniaxial vertical cylindrical stirring polymerization apparatus used in Experimental Example 1. An aqueous monomer solution consisting of 0.278 parts of methylenebisacrylamide and 176 parts of water was supplied (concentration of monomer: 34% by weight, concentration of crosslinking agent: 0.16 mol%). Nitrogen gas was blown into this aqueous solution to replace the inside of the reaction system with nitrogen. In addition, 20 reaction vessels
Dip it in a water bath at ℃ and heat it up to about 20 ℃.
And

Next, this rotary shaft was rotated at 370 rpm to obtain 3.96 parts of a 10 wt% aqueous solution of sodium persulfate.
And 3.96 parts of a 1% by weight aqueous solution of L-ascorbic acid. Polymerization starts 30 seconds after the addition, and the monomer forms a hydrogel-like crosslinked polymer as the polymerization progresses, and the hydrogel-like crosslinked polymer is gradually subdivided by the blades rotating with the rotating shaft. It was The stirring was stopped 30 minutes after the initiation of the polymerization, and the finely divided hydrogel-like crosslinked polymer was discharged. At this time, there was no deposit on the polymerization container, the rotating shaft, and the blade, and the polymer could be easily discharged simply by tilting the reaction container. The obtained hydrogel crosslinked polymer did not contain a polymer having a diameter of 10 mm or more and was subdivided into a diameter of about 2 mm. This polymer is uniformly placed on a wire mesh and heated at 150 ° C.
It was allowed to stand and dry for 30 minutes with the hot air dryer. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 7) The uniaxial vertical cylindrical stirrer used in Experimental Example 1 was charged with 25.7 parts of acrylic acid, 62.4 parts of sodium acrylate, polyethylene glycol diacrylate (average molecular weight of 487). 00 parts, and water 1
An aqueous monomer solution consisting of 76.7 parts was supplied (monomer concentration 33% by weight, crosslinking agent concentration 0.2 mol%). Nitrogen gas was blown into this aqueous solution to replace the inside of the reaction system with nitrogen.
Further, the reaction vessel was immersed in a water bath at 30 ° C. and heated to bring the reaction system to about 30 ° C.

Next, this rotary shaft was rotated at 370 rpm, and 0.51 part of a 10% by weight aqueous solution of 2,2'-azobis (2-amidinopropane) dihydrochloride was added. 51 parts, 0.04 parts of a 1% by weight aqueous solution of L-ascorbic acid, and 0.35 of hydrogen peroxide.
0.23 parts by weight aqueous solution was added. Polymerization starts 10 seconds after the addition, and the monomer forms a hydrogel-like crosslinked polymer as the polymerization progresses, and the hydrogel-like crosslinked polymer is gradually subdivided by the blades rotating with the rotating shaft. It was
The stirring was stopped 30 minutes after the initiation of the polymerization, and the finely divided hydrogel-like crosslinked polymer was discharged. At this time, there was no deposit on the polymerization container, the rotating shaft, and the blade, and the polymer could be easily discharged simply by tilting the reaction container. The obtained hydrogel crosslinked polymer does not include a polymer having a diameter of 10 mm or more,
It was subdivided into a diameter of about 2 mm. This polymer was uniformly placed on a wire net and was allowed to stand and dry for 30 minutes in a hot air dryer at 150 ° C. This dried material is crushed using a hammer mill,
A dry particulate matter of a particulate hydrous gel polymer was obtained.

Experimental Example 8 In the uniaxial vertical cylindrical stirring polymerization apparatus used in Experimental Example 1, 22.8 parts of acrylic acid, 89.4 parts of sodium acrylate, 0.17 part of trimethylolpropane triacrylate, and An aqueous monomer solution consisting of 152.6 parts of water was supplied (monomer concentration 42% by weight, crosslinking agent concentration 0.045 mol%). Nitrogen gas was blown into this aqueous solution to replace the inside of the reaction system with nitrogen. Further, the reaction vessel was immersed in a water bath at 30 ° C. and heated to bring the reaction system to about 30 ° C.

Next, this rotary shaft was rotated at 370 rpm to obtain 1.52 parts of a 10% by weight aqueous solution of sodium persulfate,
And 0.63 parts of a 1% by weight aqueous solution of L-ascorbic acid. Polymerization starts 10 seconds after the addition, and the monomer forms a hydrogel-like crosslinked polymer as the polymerization progresses, and the hydrogel-like crosslinked polymer is gradually subdivided by the blades rotating with the rotating shaft. It was The stirring was stopped 30 minutes after the initiation of the polymerization, and the finely divided hydrogel-like crosslinked polymer was discharged. At this time, there was no deposit on the polymerization container, the rotating shaft, and the blade, and the polymer could be easily discharged simply by tilting the reaction container. The obtained hydrogel crosslinked polymer did not contain a polymer having a diameter of 10 mm or more and was subdivided into a diameter of about 2 mm. This polymer is uniformly placed on a wire mesh and heated at 150 ° C.
It was allowed to stand and dry for 30 minutes with the hot air dryer. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 9) In the uniaxial vertical cylindrical stirring polymerization apparatus used in Experimental Example 1, 20.6 parts of acrylic acid, 80.9 parts of sodium acrylate, 0.15 parts of trimethylolpropane triacrylate, and An aqueous monomer solution consisting of 165.3 parts of water was supplied (monomer concentration 38% by weight, crosslinking agent concentration 0.045 mol%). Nitrogen gas was blown into this aqueous solution to replace the inside of the reaction system with nitrogen. Further, the reaction vessel was immersed in a water bath at 30 ° C. and heated to bring the reaction system to about 30 ° C.

Next, the rotary shaft was rotated at 370 rpm, and 1.38 parts of a 10% by weight aqueous solution of sodium persulfate was added.
0.57 parts of a 1% by weight aqueous solution of L-ascorbic acid was added. Polymerization starts 20 seconds after the addition, and the monomer forms a hydrogel-like crosslinked polymer as the polymerization progresses, and the hydrogel-like crosslinked polymer is gradually subdivided by the blades rotating with the rotating shaft. It was The stirring was stopped 30 minutes after the initiation of the polymerization, and the finely divided hydrogel-like crosslinked polymer was discharged. At this time, there was a small amount of deposits on the polymerization container, the rotating shaft, and the blades. There was no polymer having a diameter of 10 mm or more in the obtained hydrogel crosslinked polymer. However, about 90%
Particles of No. 3 were granulated and existed as granules of 10 mm or more. This polymer was uniformly placed on a wire net and dried by leaving it to stand in a hot air dryer at 150 ° C. for 45 minutes. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 10) The uniaxial vertical cylindrical stirring polymerization apparatus used in Experimental Example 1 was charged with 17.9 parts of acrylic acid, 70.2 parts of sodium acrylate, polyethylene glycol diacrylate (average molecular weight of 487). An aqueous monomer solution consisting of 49 parts and 177.2 parts of water was supplied (monomer concentration 33% by weight, crosslinking agent concentration 0.1 mol%). Nitrogen gas was blown into this aqueous solution to replace the inside of the reaction system with nitrogen. Further, the reaction vessel was immersed in a water bath at 30 ° C. and heated to bring the reaction system to about 30 ° C.

Next, this rotary shaft was rotated at 370 rpm, and 0.50 parts of a 10% by weight aqueous solution of 2,2'-azobis (2-amidinopropane) dihydrochloride and a 10% by weight aqueous solution of sodium persulfate were added. 50 parts, 0.03 part of a 1% by weight aqueous solution of L-ascorbic acid, and 0.35 of hydrogen peroxide.
0.22 parts by weight of aqueous solution were added. Polymerization starts 10 seconds after the addition, and the monomer forms a hydrogel-like crosslinked polymer as the polymerization progresses, and the hydrogel-like crosslinked polymer is gradually subdivided by the blades rotating with the rotating shaft. It was
The stirring was stopped 30 minutes after the initiation of the polymerization, and the finely divided hydrogel-like crosslinked polymer was discharged. At this time, there was a small amount of deposits on the polymerization container, the rotating shaft, and the blades. There was no polymer having a diameter of 10 mm or more in the obtained hydrogel crosslinked polymer. However, about 90% of the particles are granulated and 10
It was present as granules having a size of mm or more. This polymer was uniformly placed on a wire net and dried by leaving it to stand in a hot air dryer at 150 ° C. for 45 minutes. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Experimental Example 11) The same operation as in Experimental Example 1 was carried out using the same apparatus as in Experimental Example 1 except that the uniaxial cylindrical stirring polymerization apparatus was a horizontal type. The hydrogel cross-linked polymer obtained in the same process as in Experimental Example 1 did not contain a polymer having a diameter of 10 mm or more, and was subdivided into a diameter of about 3 mm. This polymer was uniformly placed on a wire net and dried by leaving it to stand in a hot air dryer at 150 ° C. for 45 minutes. The dried product was crushed using a hammer mill to obtain a dry particulate matter of a particulate hydrous gel polymer.

(Comparative Experimental Example 1) Except that the fan-shaped surface of the blade is set at an angle of 135 degrees with respect to the rotation direction of the rotation axis of the horizontal plane,
The same operation was performed using the same device as in Experimental Example 1. After the initiation of the polymerization, the monomers formed a hydrogel-like crosslinked polymer as the polymerization proceeded, but the hydrogel-like crosslinked polymer was sent upward by a blade rotating with a rotating shaft and was not fragmented. It was Stirring was stopped 30 minutes after the initiation of the polymerization, and the hydrated gel-like cross-linked polymer that had become one lump was discharged. At this time, the polymer adhered to and adhered to the polymerization container, the rotary shaft, and the blades, and it was necessary to remove the adhered matter and cut the polymer when discharging. The polymer was uniformly placed on a wire net and statically dried with a hot air dryer at 150 ° C. In the drying for 60 minutes, many polymers which were not dried and contained water were found. An attempt was made to grind this polymer using a hammer mill, but the water-containing polymer was so soft that it could not be ground.

(Comparative Experimental Example 2) The same apparatus as in Experimental Example 1 was used and the same operation was performed except that the shape of the blade was circular. After the initiation of the polymerization, the monomers formed a hydrogel-like crosslinked polymer as the polymerization proceeded, but the hydrogel-like crosslinked polymer was not subdivided by the blades rotating with the rotating shaft. Stirring was stopped 30 minutes after the initiation of polymerization, and the hydrogel crosslinked polymer was discharged. At this time, the polymer adhered to and adhered to the polymerization container, the rotary shaft, and the blades, and it was necessary to remove the adhered matter and cut the polymer when discharging. The water-containing gel-like cross-linked polymer obtained was 10
90% or more of the polymers had a diameter of mm or more. The polymer was uniformly placed on a wire net and statically dried with a hot air dryer at 150 ° C. In the drying for 60 minutes, many polymers which were not dried and contained water were found. An attempt was made to grind this polymer using a hammer mill, but the water-containing polymer was so soft that it could not be ground.

[0056]

In the apparatus for producing hydrogel-like crosslinked polymer particles according to the present invention, since a plurality of blades locally cut the hydrogel-like crosslinked polymer, the load on the polymer is small and the rotational driving force is also small. You may Furthermore, since the hydrogel crosslinked polymer flows due to its own property, that is, the property that the tackiness decreases as the polymerization progresses, it is not necessary to separately install a device and the device can be downsized. Is.

When the plurality of blades are formed of a plate-like member and the plane in the direction intersecting the rotation axis is substantially perpendicular to the rotation axis, the load of the polymer is smaller. Therefore, the device can be downsized. When the two adjacent blades are arranged so as not to overlap each other when viewed from the direction along the rotation axis, the plurality of blades flow in the direction along the rotation axis of the hydrogel crosslinked polymer. The effect of not hindering is increased. Therefore, the synergistic effect with the effect that the plurality of blades locally cut the water-containing gel-like cross-linked polymer makes it possible to make uniform fine particles and downsize the apparatus.

When the plurality of blades are strip-shaped and the adjoining two blades are installed in opposite directions to the rotation axis, the hydrogel crosslinked polymer flows in the direction along the rotation axis. The effect of not hindering is increased. Therefore, the synergistic effect with the effect that the plurality of blades locally cut the water-containing gel-like cross-linked polymer makes it possible to make uniform fine particles and downsize the apparatus.

When the plurality of blades are fan-shaped and the adjoining two blades are installed in opposite directions, a uniform fine particle is obtained without impeding the flow of the hydrogel crosslinked polymer in the same manner as described above. It is possible to make particles and to downsize the device. In the method for producing a water-containing gel-like crosslinked polymer particle according to the present invention, the water-containing gel-like crosslinked polymer is cut without interrupting the flow in the reaction vessel, the polymer in the reaction vessel is efficiently and It is made into fine particles uniformly. At this time, the hydrogel crosslinked polymer flows due to its own property, that is, the property that the tackiness decreases as the polymerization progresses, so there is no need to provide a separate device for transportation, and a simple device is used. As a result, hydrogel-like crosslinked polymer particles can be obtained.

Even when the monomer is at least one selected from the group consisting of acrylic acid or methacrylic acid neutralized with an alkali metal base or ammonium base in an amount of 50 to 100 mol%, acrylamide and methacrylamide, it is possible to obtain Since the obtained water-containing gel-like crosslinked polymer is efficiently and uniformly made into fine particles, it is difficult to obtain coarse particles.

In the material supplying step, the weight concentration M% of the monomer and the molar concentration Xm of the crosslinking agent with respect to the monomer are
In the case of the step of supplying the monomer and the crosslinking agent so that the ol% satisfies the relational expression of M ≧ −60X + 42, the water-containing gelled crosslinked polymer produced by polymerization is the plurality of blades. Makes it easier to make fine particles,
Coarse particles are hard to form. Further, since the particles are made into fine particles to increase the surface area, it is extremely easy to control the polymerization temperature, and it is possible to increase the polymerization rate to improve the productivity. Furthermore, since the hydrous gel-like crosslinked polymer particles obtained by the present invention have a large surface area, they can be easily dried in a short time by hot air drying or the like.

[Brief description of drawings]

FIG. 1 is an apparatus for producing hydrogel-like crosslinked polymer particles used in one embodiment of the present invention.

FIG. 2 is a blade showing an embodiment of the present invention.

FIG. 3 is a blade showing an embodiment of the present invention.

[Brief description of reference numerals]

 1 Reaction container 2a, 2b, 2c, 2d, 2e Blade 3 Rotating shaft 4 Motor 5 Sealing member

Claims (8)

[Claims] 1. An apparatus for obtaining a hydrogel-like crosslinked polymer by polymerizing a monomer by aqueous solution polymerization in the presence of a crosslinking agent, and for making the polymer into fine particles. A reaction container for accommodating the crosslinked polymer, a rotating shaft rotatably arranged in the reaction container, locally supported by the rotating shaft, and locally cutting the hydrogel-like crosslinked polymer, and A plurality of blades that allow the hydrous gel-like crosslinked polymer to flow in a direction along the rotation axis,
An apparatus for producing hydrogel-like crosslinked polymer particles, comprising: 2. The hydrogel according to claim 1, wherein the plurality of blades are formed of a plate-shaped member, and a plane in a direction intersecting the rotation axis is substantially perpendicular to the rotation axis. For producing granular cross-linked polymer particles. 3. The hydrogel cross-linking stack according to claim 1, wherein the plurality of blades are arranged such that two adjacent blades do not overlap when viewed from a direction along the rotation axis. Equipment for producing coalesced particles. 4. The apparatus for producing hydrogel-like crosslinked polymer particles according to claim 3, wherein the plurality of blades are strip-shaped, and the adjoining two blades have opposite installation directions with respect to the rotation axis. 5. The apparatus for producing hydrogel-like crosslinked polymer particles according to claim 3, wherein the plurality of blades are fan-shaped, and two adjacent blades are installed in opposite directions to the rotation axis. . 6. A method for producing hydrogel-like crosslinked polymer particles, which comprises polymerizing a monomer by aqueous solution polymerization in the presence of a crosslinking agent to obtain a hydrogel-like crosslinked polymer, and micronizing the polymer. There, a material supplying step of supplying an aqueous solution containing the monomer and the crosslinking agent to a reaction vessel, a reaction step of polymerizing the monomer and the crosslinking agent to obtain a hydrogel-like crosslinked polymer, A hydrogel crosslinked polymer comprising a cutting step of locally cutting the hydrogel crosslinked polymer without disturbing the flow in the reaction vessel by a blade rotatably arranged in the reaction vessel. Method for producing particles. 7. The monomer is at least one selected from the group consisting of acrylic acid or methacrylic acid neutralized with an alkali metal base or an ammonium base in an amount of 50 to 100 mol%, acrylamide and methacrylamide. Item 7. A method for producing hydrogel-like crosslinked polymer particles according to Item 6. 8. In the material supplying step, the weight concentration M% of the monomer and the molar concentration Xm of the cross-linking agent with respect to the monomer are Xm.
The method for producing hydrogel crosslinked polymer particles according to claim 7 or 8, which is a step of supplying the monomer and the crosslinking agent so that ol% satisfies a relational expression of M ≧ −60X + 42.