JPS61118405A - Production of partial hydrolyzate of acrylamide polymer - Google Patents

Abstract

PURPOSE:A polymer gel of acrylamide is particulated and simultaneously partial hydrolysis is effected in the presence of an alkaline substance to enable economical and high-efficiency production of a hydrolyzate which is used as a paper strong agent, thicknener or soil conditioner. CONSTITUTION:An acrylamide polymer gel resultant from the polymerization of an aqueous solution of an acrylamide monomer is crushed into particles of 3-20mm particle size on the average, then particulated into particles of 0.3-3mm diameter by operating an upright cutter which is composed of stationary blades 2, 2' and rotatory blade 1 and has a zone C where the polymer gel to be particulated stays so that the average residense time becomes more than 3min. At this time an alkaline substance or a mixture thereof wi-th a compound bearing or generating active hydrogen atoms is admixed to effect partial hydrolysis in a blade mixer which is coated with a fluorine-containing copolymer or provided with the films of the resin and has blades whose setting angles arevariable to the shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to 11 methods for producing partially hydrolyzed acrylamide polymers. More specifically, it includes a step of refining the acrylamide polymer gel obtained by polymerization and mixing it with an alkaline substance or an alkaline substance and a compound having or generating active hydrogen, and The present invention relates to a method for producing a partially hydrolyzed acrylamide polymer by mixing a gel with an alkaline substance or an alkaline substance and a compound having or generating active hydrogen.

[Prior Art] Conventionally, homopolymers of acrylamide, copolymers mainly composed of acrylamide with other polymerizable monopolymers, or alkaline hydrolysates thereof have been used as paper strength agents and thickeners. It is widely used as a soil conditioner, crude oil recovery agent, wastewater treatment agent, etc.

Methods for producing these water-soluble acrylamide polymers include bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization, but it is important that the polymer has an essentially high molecular weight. Therefore, an aqueous solution polymerization method is usually adopted in many cases.

In order to obtain a polymer with a very high molecular weight and good water solubility by aqueous solution polymerization, it is necessary to prevent crosslinking during the polymerization reaction stage, and it is necessary to carry out the polymerization at a relatively low concentration. be.

However, in recent years, as emphasis has been placed on economic efficiency such as transportation costs and storage costs, powder products have become the mainstream of production rather than liquid products, and when water-soluble polymerization is carried out at low concentrations, When powdering a polymer gel, a large amount of water must be volatilized and dried, which has the drawback of increasing utility costs for powdering.

Acrylamide-based polymer partial hydrolyzate is mainly produced by partially hydrolyzing acrylamide-based polymer gel using an alkaline substance. However, when producing acrylamide-based polymer partial hydrolyzate, It is necessary to uniformly permeate an alkaline substance or the like into the interior of the polymer gel to cause uniform partial hydrolysis, and for this purpose, it is desirable to use a polymer gel with a relatively low concentration. However, when a polymer gel with a low concentration is used, the utility cost for volatilizing water increases, and the polymer gel particles adhere to each other, resulting in agglomeration and drying. This is not preferable because it significantly reduces the drying efficiency in the step.

In order to eliminate such drawbacks, research has been conducted to reduce utility costs in the powdering step by polymerizing at the highest possible monomer concentration, and numerous patent applications have been filed.

However, vinyl monomers such as acrylamide and acrylic acid inherently have an extremely strong tendency to crosslink and become three-dimensional. For example, in the case of anionic or nonionic, at most 20 to 30
The polymerization must be carried out while maintaining the concentration at a relatively low concentration of 1% (1%, the same applies hereinafter).

When acrylamide or a monomer solution mainly consisting of acrylamide at the above concentration is polymerized, a hard or highly elastic gel-like material with no fluidity is obtained. Therefore, for example, if you try to alkali hydrolyze a mass or sheet of gel polymer as it is without mechanically crushing it, you will have to keep it in contact with an alkaline substance for a very long time. The reality is that it is difficult to uniformly hydrolyze the inside of the polymer gel even if the polymer gel is kept in contact for a long time, resulting in a significant decrease in commercial value. Therefore, generally, a method is employed in which the obtained polymer gel mass or sheet-like material is crushed by some mechanical means into small agglomerated particles, and then brought into contact with an alkaline substance or the like.

Usually, as a method for mechanically crushing the polymer gel obtained by polymerization, an extrusion molding machine such as a meat grinder is used. However, in this case, there are drawbacks such as a decrease in machine efficiency due to *m and a decrease in molecular weight due to molecular cleavage, and the coarsely crushed particles have a diameter of 10 to 20 mm. degree and large,
Moreover, since it becomes ribbon-like or string-like, even if it comes into contact with alkaline substances, the substance is sufficient to reach the inside.

It has the disadvantage that it penetrates in some cases and does not, making it difficult for uniform hydrolysis to occur.

The present inventors have discovered that the crushed particles as described above are large in size,
In addition, to solve the problem of particles adhering to each other,
Conducting research on methods for refining polymer gel particles, 1982
A patent application (title of the invention: ``Method for refining water-soluble polymer gel,'' hereinafter referred to as B application) was filed on November 6, 2017. In addition, he established a method for partially hydrolyzing the polymer by simultaneously mixing the polymer gel and an alkaline substance in the process of refining the particles, and filed a patent application on November 12, 1980 (title of invention: We have developed a method for producing fine acrylamide-based polymer particles with less residual acrylamide layer (hereinafter referred to as Application C).

Partial hydrolysis of acrylamide-based polymer gel using an alkaline substance etc. can be sufficiently achieved by the method described in the specification of the C application, but this method involves making the polymer gel fine and using an alkaline substance etc. Because partial hydrolysis is carried out at the same time, for example, if the target is to achieve a relatively high partial hydrolysis rate of an acrylamide polymer, it is necessary to use a large amount of alkaline substances; A large amount of heat of dissolution, such as It is necessary to maintain it at a somewhat high concentration for a sufficient period of time, but the method described in the specification of application B requires cutting machines to be combined in multiple stages, and improvements are needed in terms of making the equipment more compact. Since a large amount of ammonia gas is generated in the partial hydrolysis step, it is necessary to absorb the ammonia gas efficiently so as not to discharge it out of the system.This method cannot be said to be completely satisfactory.

[Problems to be Solved by the Invention] The present invention solves problems that occur when a highly concentrated acrylamide polymer gel is coarsely crushed using an extrusion molding machine such as a meat grinder! L! Disadvantages include a reduction in machine efficiency due to abrasion and a decrease in molecular weight due to molecular breakage, and the coarsely crushed particles are large and string-like, with varying particle sizes, so even if they come into contact with alkaline substances, the internal To solve the problem that the substance penetrates sufficiently in some cases and not in others, making it difficult to achieve uniform hydrolysis, or in the case of the method described in the specification of application C, problems such as those mentioned in (1) to (2) above. It was made for the purpose of

[Means for Solving the Problems] In order to economically, efficiently produce a uniformly partially hydrolyzed acrylamide polymer,
■Maintaining a high monomer concentration during the polymerization stage; ■Uniformly hydrolyzing the high-concentration polymer gel obtained by polymerization with an alkaline substance; improving both quality and economy. With this in mind, as a result of extensive studies, we have arrived at the present invention.

That is, in the present invention, an acrylamide-based polymer gel obtained by polymerizing an aqueous solution of an acrylamide-based monomer is crushed into particles having an average particle size of 3 to 20 mm. A step of cutting the polymer gel into fine particles of 0.3 to 3 JllIφ by using a vertical cutting machine having an area where the polymer gel to be obtained stays and operating under conditions where the average residence time is 3 minutes or more, Mixing an alkaline substance or an alkaline substance and a compound having or generating active hydrogen, and coating the resulting finely granulated polymer gel with a fluorine-containing copolymer IMIll or a film made of the copolymer resin. A method for producing a partially hydrolyzed acrylamide polymer, characterized in that partial hydrolysis is carried out by mixing with a paddle-type stirrer equipped with a paddle whose shaft angle is variable. Regarding.

[Example] The acrylamide monomer used in the present invention is (meth)
Acrylamide or (meth)acrylamide 30
% or more, and the remaining components include other water-soluble vinyl monomers.

Specific examples of the other water-soluble vinyl monomers include water-soluble vinyl monomers such as acrylic acid, methacrylic acid, vinyl sulfonic acid, acrylamide-methylpropylsulfonic acid, and salts thereof. ,
It is not limited to these. These may be used alone together with (meth)acrylamide, or two or more of them may be mixed and used together with (meth)acrylamide.

The acrylamide monomer includes a monomer that is essentially insoluble in water to the extent that the resulting polymer is water-soluble;
For example, hydrophobic monomers such as acrylonitrile, (meth)acrylic esters, vinyl acetate, and styrene may be used in combination.

There are no particular limitations on the method of polymerizing the acrylamide monomer, such as thermal polymerization using a radical polymerization initiator such as a normal persulfate or an azo initiator, or a conventional persulfate/amine or persulfate method. Common methods include a redox polymerization method using a redox polymerization initiator such as a salt/sulfite, a photopolymerization method using a photopolymerization initiator such as benzoin or benzoin alkyl ether, or a radiation polymerization method. Generally, by this method,
An aqueous solution of an acrylamide monomer at a predetermined concentration is polymerized until it no longer flows freely.

It is preferable for the polymer gel obtained using an acrylamide monomer to have as high a concentration as possible from the viewpoint of improving productivity, and also to reduce stickiness during crushing and prevent crushed materials from adhering to each other. It is also preferable from this point of view.

In general, nonionic or anionic polymer gels obtained using (meth)acrylamide or (meth)acrylamide and, for example, acrylic acid, are
It is 20-60%, preferably 30-45%. When the concentration of the aqueous solution is less than 20%, the polymer gel itself becomes essentially flexible and weak, making it impossible to refine the polymer gel according to the present invention, resulting in a lump-like shape when an alkaline substance is added. This is not desirable because it causes Polymer gels with a water-soluble concentration of more than 60% are in the form of particles that do not adhere to each other, but crosslinking occurs and the water solubility is significantly reduced, resulting in loss of commercial value, which is also undesirable.

There are no particular limitations on the form of the polymer gel. However, for example, as described in the specification for which the present inventors have already filed a patent application dated November 6, 1980 (title of the invention "Method for crushing water-soluble polymer gel", hereinafter referred to as application specification A), In order to cut efficiently with a pair of roller-type cutters that rotate in the direction of engagement with each other, the polymer gel must be inserted into the roller-type cutters smoothly.
The thickness of the polymer gel is 2 to 30 mm, preferably 5 to 15 mm.
It is preferable to form a thin layer such as m. For example, when an acrylamide monomer aqueous solution is polymerized using a dish-shaped, plate-shaped, or tray-shaped container or a movable belt, it can be made into an iI-like shape. A method in which polymerization is carried out in a thin layer on a movable belt is a preferable method because the subsequent crushing process is continuous.

If the size of the crushed small lumps falls outside the average particle size range of 3 to 20 g, the cutting ability of the vertical cutting machine in the cutting process tends to decrease, and the cutting capacity of the vertical cutter in the cutting process tends to decrease. If too much polymer gel with an average particle size exceeding This will cause an unnecessary vicious cycle.

Next, a cutting machine and a cutting machine are used to finely granulate the crushed polymer gel into small pieces having an average particle size of 3 to 20 m, and to mix the alkaline substance or an alkaline substance and a compound having or producing active hydrogen. The method will be explained, and a paddle-type stirrer will be described that mixes the finely divided polymer gel with an alkaline substance or an alkaline substance and a compound having or generating active hydrogen, and partially hydrolyzing the mixture under predetermined conditions. explain.

In order to uniformly and efficiently partially hydrolyze an acrylamide-based polymer, it is important to know how to make the polymer gel into fine particles, and how to make the polymer gel particles in a solid state and an alkaline substance in a liquid or powder form. Alternatively, it is important how to uniformly mix an alkaline substance and a compound having or generating active hydrogen, and how to uniformly permeate the inside of the polymer gel.

As the alkaline substance used in the present invention, any alkaline chemical agent that can hydrolyze acrylamide, such as caustic soda, caustic potash, soda ash, sodium phosphate, and sodium borate, can be used. The alkaline substance may be used in any form such as powder, granules, flakes, liquid, or slurry, but from the viewpoint of avoiding mutual adhesion of the finely divided polymer gels, powder to It is preferable to add it in the form of a slurry.

The amount added may be set according to the target hydrolysis rate.

The compound having active hydrogen or producing active hydrogen used in the present invention functions to eliminate the remaining monomer, and specific examples include sulfite,
Compounds containing mercapto groups such as bisulfite, mercaptopropionic acid, thioglycolic acid, thioglycerin, thioglycol, etc., or compounds containing amino groups such as dimethylamine, methylethylamine, diethylamine, ammonia, methylethanolamine, jetanolamine, etc. etc. At least one or two or more of these compounds having active hydrogen or producing active hydrogen are selected and used in combination with the alkaline substance. The form of use may be powder, granules, flakes, liquid, or slurry.

The compound may be added in an amount equal to or slightly in excess of the stoichiometric amount of the total amount of monomers contained in the polymer gel. Generally, addition of about 2% or less of the total amount of monomers used prior to polymerization is sufficient.

When an alkaline substance and a compound that has active hydrogen or that generates active hydrogen are used together, there are no particular limitations on the proportions used, and they should be used according to the purpose of each use (hydrolysis and disappearance of remaining monomers). Bye.

Figure 1 shows a schematic plane of a vertical cut used to refine the crushed polymer gel used in the present invention to an average particle diameter of 3 to 20 as+ to 0.3 to 3 alIφ, preferably 1 φ or less. It is an explanatory diagram, and FIGS. 2 and 3 are schematic cross-sectional explanatory diagrams.

In Figure 1, (1) is a rotating blade, (2) and (2')
are the first and second fixed blades, (3) is the pre-cutter, (4) is the screen, (5) is the rotating shaft of the rotary blade (1), (6) is the bottom, and (7) is the discharge hole. be.

The vertical cutting machine used in the present invention shown in FIG. ), and has a retention area (C) that is half-moon shaped when viewed from above and allows retention for more than 3 minutes, and has a drive rotation axis (the axis of the rotary blade in Figures 1 and 2). (5)) is facing vertically upward, that is, it is a vertical point.

In Fig. 3-1, among the supplied angular polymer gels of 3 to 21)el, as shown in Fig. 1, the rotary blade (1) installed inside the main body of the vertical cutting machine axis (51
By rotating the cutting blade at the tip of the pre-cutter (3) fixed to the precutter (3), a relatively large polymer gel having an inner diameter of 10 to 20 mm among the 3 to 20 a+m angular polymer gels is crushed.

At this time, the angular polymer gel of 3 to 20M is attached to the shaft of the rotary blade (
The first key point of the present invention is to feed (drop) the rotary blade from the axis of S toward the axis (9) of the rotary blade. , can be first converged to a diameter in the range of 3 to 5 #I.The 3 to 20 m square polymer gel thus supplied is
It is first arranged at ~5m. In this way, 3~51m1
The polymer gel cut in the + range is cut into a gap of 1 s or less between the first fixed blade [21] assembled in the vertical cutting machine body as shown in Figure 1 and the rotating rotary blade (1). It is wedged in and cut off at the same time as it is wedged in. When viewed from above, the cut polymer gel has an arc-shaped screen (4), the outer peripheral edge of the rotating rotary blade (1), and the first fixed blade (
a and the second fixed blade (2') (a
) along the rotating direction of the rotary blade (1) to the second fixed blade (2-).

The second point of the method of the present invention is that the cut polymer gel moving in the region (a) has a diameter smaller than the pore diameter (Ds) of the screen (4) shown in Fig. 3-2. The polymer gel is scattered outward by centrifugal force, forming a screen 4)
The polymer gel passes through the pores, is discharged from the region R(a) to the discharge hole (7), and is separated from the polymer gel, which is coarser than the pore diameter (Ds) of the screen.

On the other hand, among the cut polymer gels moving in the area (a), the polymer gel with a diameter larger than the pore size (O8) of the screen (4) is again placed in the second position as shown in FIG. The area (b) is sandwiched between the fixed blade (2') and the rotating blade (1), and after being cut, is surrounded by the circumference drawn by an arc with the same diameter as the screen (4) and the rotating blade (1). Rotating blade inside (1)
along the direction of rotation. Then, the polymer gel moving in region (b) again moves between the first fixed blade (a) and the rotating blade (
1) and is cut, and the same cutting is repeated thereafter.

In this way, the diameter of 3 to 20411111 of the polymer gel supplied (falling) toward the rotation axis (5) located downward from above the axis of the vertical cutting machine (S) is determined by the vertical cutting machine. Hole diameter (Os) of screen (4) from machine discharge hole' (7)
It is separated into smaller pieces and discharged continuously, allowing for desired cutting. At this time, if the hole diameter is larger than that of the screen (4), the second fixed blade (2
-) and the rotating blade (1) to reduce the diameter of the polymer gel, but thirdly, the area (
1)) The cut polymer gel that has entered the retention area (
C) is stagnation. After that, the retention area (C)
The polymer gel, which stays for at least 3 minutes on average at The residence time exceeds at least 3 minutes, and the polymer gel staying in the residence area (C) is mixed extremely vigorously due to the centrifugal force of the rotating blade (1).
As it is stirred, as shown in Figure 3-1, alkaline substances and (
Or) By incorporating a compound having active hydrogen or generating active hydrogen, it becomes possible to cause an efficient chemical reaction with the acrylamide in the acrylamide polymer gel to eliminate the acrylamide. Furthermore, mixing and stirring for 3 minutes or more on average helps complete the chemical reaction to further eliminate acrylamide.

As described above, the device characteristics of the method of eliminating unreacted residual acrylamide in the present invention are as follows:
The axis (51'') of the rotary blade in FIGS. 2 and 2 points vertically upward, and the mechanical structure is vertical.

The vertical cutter used in the present invention is different from typical and common commercially available crushers such as Feather Mill and Fitzmill, because it can maintain the average crushing residence time of the material to be crushed at 3 minutes or more. Since the polymer gel is discharged with an extremely small number of cuts without being subjected to many cuts, a uniform fine-grained gel can be obtained. The structure of the cutting machine is characterized by adjusting the gap between the vertical fixed blade (21, (2M) and the rotary blade (1) installed vertically inside the cutting machine, and by adjusting the gap between the sieve hole diameter (O3 ) and by arranging a plurality of vertical cutting machines in series, that is, by passing the cutting machines two to several times, it is possible to control the residence time of the grinding, for example, by changing the The point is that it becomes easy to cut into small particle size polymer gels as shown below.The technology for refining crushed polymer gels using a vertical cutting machine with such a structure has not been established in the past. It is something that

Therefore, since the polymer gel is finely granulated in this way,
Incorporation of an alkaline substance or an alkaline substance and a compound having or generating active hydrogen into the polymer gel becomes easy, and partial hydrolysis of the polymer becomes uniform and efficient.

For example, in the first step, cutting is performed using a cutting machine equipped with a screen of 3 IIRφ, and it is possible to obtain a finely divided polymer gel having a uniform particle size of about 3IIRφ or less. Then, in the second step, the grains are made into fine grains using a cutting machine equipped with a 2#IIφ screen, and in the third stage, the grains are refined using a cutting machine equipped with a 1m+φ screen.
Fine particles are obtained which are uniform in diameter less than φ and have a rounded appearance. In this way, by selecting a screen that matches the target particle size, the target particle size can be obtained.

In addition, when the manufacturing method of the present invention is adopted, almost no dust is generated during the step of refining the polymer gel, which is essentially in a wet state, and the particle size distribution is uniform, so to speak, close to monodisperse. It will be done. Moreover, the alkaline substance and the compound having or producing active hydrogen can be easily dispersed in the finely divided polymer gel, thereby promoting a uniform hydrolysis reaction.

The paddle-type stirrer used in the present invention is, for example, one embodiment of which is shown in FIG. 4 and FIG. 5, which is a sectional view taken along line cc'.

Blade rotation axis (main) (9), blade rotation/axis (sub) (10)
) is attached with a seed-shaped blade (8), and the attached seed-shaped blade (81) can change its angle in the range of 30 to 90 degrees with respect to the rotation axis, so that sufficient residence time can be obtained. It is designed to.

The seed-shaped blade (8) attached in this way sufficiently stirs and mixes the finely divided polymer gel sent to the stirring 1m (15) until it is carried out from the stirrer outlet. As a result, the alkaline substance or the alkaline substance and the compound having or generating active hydrogen are uniformly and efficiently permeated into the interior of the polymer gel.
As a result, the partial hydrolysis reaction also becomes uniform.

When partially hydrolyzing a polymer gel, an alkaline substance or an alkaline substance and a compound having active hydrogen or generating active hydrogen may be used to partially hydrolyze the polymer gel by 0.3 to 3
Although it is added to a cutting machine that cuts amφ, it may also be added to a paddle-type stirrer, or an appropriate amount may be divided and added to each.

Particularly in the case of highly partial hydrolysis, rather than adding it all at once to the cutting machine, it is better to add it in half, for example, by dividing it into the cutting machine and stirring, to increase the efficiency of granulation in the cutting machine. Preferable for its meaning.

The paddle type stirrer used in the present invention is preferably equipped with a jacket (16) for heating or cooling. , for example 60-80
The hydrolysis reaction may be promoted by passing hot water at ℃ and stirring under heating.
3) You may stir while flowing cooling water using a jacket heated steam outlet vibrator (14). When heated normally, sufficient hydrolysis can be achieved within one hour.

When the hydrolysis reaction occurs, ammonia gas is generated,
This ammonia gas can be removed, for example, by installing a duct in a paddle-type stirrer to suck it in, and then sealing it in, for example, a sulfuric acid aqueous solution tank.

The wall surface of the paddle-type stirrer must be coated with a fluorine-containing copolymer resin or attached with a film made of the copolymer resin. Such a structure can prevent the polymer gel from adhering to the wall surface.

Specific examples of the fluorine-containing copolymer resin include tetrafluoroethylene-ethylene copolymer resin.

A metal with high light reflectivity, such as aluminum, is deposited on the back side of a film made of fluorine-containing copolymer resin that is installed inside the paddle-type stirrer, and a compound having active hydrogen or a compound that generates active hydrogen is deposited on the back side of the film made of fluorine-containing copolymer resin. When used in combination with an alkaline substance, if a method of irradiating ultraviolet rays from above is adopted, the mechanism of action is unknown, but the polymer gel contains residual monomers and active hydrogen. Alternatively, since the reaction with a compound that generates active hydrogen is significantly promoted, remaining monomers can be efficiently eliminated.

Irradiation of ultraviolet rays can be easily achieved, for example, by providing a pressure-resistant glass window in a part of the upper lid of the paddle-type stirrer, and installing an ultraviolet ray generating source such as a low-pressure mercury lamp or a xenon lamp above the window.

The polymer gel partially hydrolyzed as described above is transferred to a drying step and dried, if necessary.

In the drying process, commonly used groove dryers, band dryers, fluidized dryers, etc. are used, and usually 50 to 1
By drying at a temperature of 50° C. for about 30 to 60 minutes, powder with a moisture content of 10% or less can be obtained. As necessary,
It may be pulverized, sized, powdered, etc.

Hereinafter, the manufacturing method of the present invention will be explained based on Examples, but the present invention is not limited only to these Examples.

Example 1 20 g of a 1% potassium persulfate aqueous solution, 5 g of a 1% sodium bisulfite aqueous solution and 1 g of dioctyl sulfosuccinate sodium salt were dissolved in a monomer aqueous solution in which 400 g of acrylamide was dissolved in 500 g of deionized water, and finally deionized. The total volume was made up to 10,009 ml with ionized water. The resulting aqueous solution was placed in a deoxidizing tank, and dissolved oxygen was removed by passing nitrogen gas through it.

Next, a stainless steel square polymerization tank (1a100..10
G411. When a polymerization reaction was carried out for 3 hours at an external temperature of 30° C. in a chamber with a height of 150 mm, a gel-like polymer with strong elasticity was obtained.

The obtained block mass is reduced to 5#I in terms of particle size using an electric meat grinder.
After cutting into granular small pieces of I+, as a first step, 3sI
It is cut with a cutting machine equipped with a φ screen, and then the second
The stage is 1.5mm diameter screen, and the third stage is 0.5mm diameter screen.
It was cut using a cutting machine equipped with an 8jllφ screen.

In addition, when refining the particles using a cutting machine equipped with a 3awφ screen, powdered caustic soda 55 with an average particle size of 1jIlφ was used.
g to mix the polymer gel particles and caustic soda. The total contact time between the polymer gel particles and the caustic soda is 1
It was 5 minutes.

The resulting finely divided polymer gel had a final average particle diameter of 0.8 mφ.

The resulting polymer gel containing caustic soda having an average particle diameter of 0.8 awφ was stirred for about 30 minutes in a paddle type stirrer similar to that shown in FIGS. 4 and 5. The mixture was mixed and then dried in a hot air dryer at 80° C. for 25 minutes to obtain a powder polymer with a moisture content of 8.3%.

The obtained powder polymer has approximately 2% of the polymerized acrylamide.
5 mol% is hydrolyzed and the intrinsic viscosity in 1N NaCl is 23 dJ! /g, no water-insoluble substances were observed when dissolved in water. Further, the amount of residual acrylamide contained in the powder polymer was 0.18%.

Example 2 A powdered polymer was obtained in the same manner as in Example 1 except that 5 g of sodium sulfite powder was added simultaneously with powdered caustic soda.

The obtained powdered polymer had a moisture content of 8.0%.

The resulting powdered polymer contains about 20% of the polymerized acrylamide.
2 mol% was hydrolyzed, the intrinsic viscosity in 1N NaCI was 22.5 dll/g, and no water-insoluble substances were observed when dissolved in water. Further, the amount of residual acrylamide in the polymer powder was 0.03%.

Example 3 A tetrafluoroethylene-ethylene copolymer film whose back surface was vapor-deposited with aluminum was attached to an endless belt made of stainless steel with a width of 450 m and an effective length of 3000 #ll, and hot to cold water was supplied from below to the endless belt. As a movable support for polymerization,
Installed in a room completely filled with nitrogen gas, with a distance of 100 m.
Operated at a constant speed of 15°C from the bottom of the belt.
water was sprayed. Further, a low-pressure mercury lamp was installed as an ultraviolet irradiation source on the upper part of the movable support, and the intensity of the ultraviolet rays was set to 50 cm/m.

Concentration 40 adjusted to pH 8 with 10% caustic soda aqueous solution
% acrylamide aqueous solution layer was thoroughly degassed with nitrogen gas, and 13.54 J of a layer was placed on the belt in operation.
! It was fed stationarily from one end of the belt at a rate of 1/hr.

In addition, a temporary storage tank with an agitator installed above the belt (capacity 5
From j), a 5% methanol solution of benzoin isopropyl ether as a polymerization initiator was fed into the monomer aqueous solution at a rate of 30 m/hour, and the monomer aqueous solution and the polymerization initiator were uniformly mixed while being fed onto the belt and irradiated with ultraviolet rays. Polymerization was carried out using

Under the above conditions, the time during which the aqueous monomer solution was subjected to polymerization on the belt was 30 minutes, and the layer of the aqueous monomer solution during polymerization was about 5 m+.

Thirty minutes after the start of supply of the monomer aqueous solution, a sheet-like polymer gel having a thickness of about 5 m was replaced from the other end of the endless belt. The obtained polymer gel was in a state where it could be easily peeled off from the belt surface by hand, and continuous polymerization for about 3 hours was possible.

The temperature of the resulting polymer gel was about 20°C.

The polymer gel sheet continuously obtained from the other end of the endless belt is continuously fed to a crusher as described in the specification of the A application, crushed, and a angular polymer gel of about 3 x 5 x 5 squares is produced from the outlet of the crusher. Obtained.

After that, using a cutting machine shown in Figures 1 to 3-1, cutting was performed using a cutting machine equipped with a screen of approximately 3 g + φ, while blowing cold air at approximately 15°C, and then cutting with a screen of 2#llφ and then a screen of 1 Cutting was carried out using a cutting machine equipped with a screen of #llφ to obtain a finely divided polymer gel having a size of about 1#lφ or less. In addition, when refining, a slurry with a specific gravity of 1.55 consisting of 4 parts of caustic soda flakes prepared in advance, 0.3 kg of sodium sulfite, and 4.3 kg of pure water was cut in the first stage at a speed of 1.8541/hr. I put it into the machine. Moreover, the total average residence time in the tank of the cutting machines from the first stage to the third stage was about 30 minutes.

The obtained finely divided polymer gel containing a slurry of caustic soda and sodium sulfite having a diameter of about 1 m or less is shown in FIGS.
Using a paddle-type stirrer as shown in Figure 5, the average residence time was approximately 50°C at 50°C under irradiation with a low-pressure mercury lamp in a stirrer coated with a tetrafluorinated ethylene-ethylene copolymer resin with aluminum vapor-deposited on the back side. Mix for 30 minutes,
Then, it was dried for about 30 minutes using a band type dryer blowing hot air at 80°C.

The moisture content of the obtained polymer powder was 8.5%, and the intrinsic viscosity (INNaCI width) of the polymer powder was 25.5617 g.
, a hydrolysis rate of polymerized acrylamide of about 45 mol%,
The residual acrylamide contained in the polymer powder is 0.02
4%, and when made into a 1% aqueous solution, the water-insoluble substance is
was hardly recognized.

[Effects of the Invention] By using the method of the present invention, 1) the polymer gel can be continuously crushed and pulverized; 2) the polymer gel can be made into extremely fine granules; As a result of preventing granules from adhering to each other,
Significantly improves drying efficiency in the next process ■The amount of, for example, 100 mesh bath contained in the finely granulated product (powder) is extremely small, eliminating dust generation and dusting, which were previously seen as problems. Shitsuru ■ There is almost no decrease in the polymer or molecular weight when crushing or crushing the polymer gel (conventional methods cause a significant decrease in molecular weight, and improvements are required) ■ Partial hydrolysis rate of acrylamide polymers Even if the target is a relatively high polymer gel, the polymer gel will not become lumpy and the particles will be sufficiently fined. It can be maintained for a long time and the equipment can be made more compact. ■The effects of hangings can be changed to efficiently absorb the ammonia gas produced in the partial hydrolysis stage so that it is not unnecessarily discharged outside the system.

[Brief explanation of the drawing]

Figures 1 to 3-1 are explanatory diagrams of an embodiment of the vertical cutting machine used in the present invention, and Figure 3-2 is a three-dimensional illustration of the structure of the screen used in Figure 3-1. Figure, Figure 4~
FIG. 5 is an explanatory diagram of one embodiment of the horizontal stirrer used in the present invention. (Main symbols in the drawing) (1): Rotating blade (2): 1st fixed blade (2'): 2nd fixed blade (C): Retention area (81: II type blade (9) Two blades Rotation shaft (main) (1G): Blade rotation shaft (sub) (15): Type I stirrer 3-10 years old 3-2 years old

Claims (1)

[Claims] 1. An acrylamide polymer gel obtained by polymerizing an aqueous solution of an acrylamide monomer with an average particle size of 3 to 20 mm.
Then, using a vertical cutting machine consisting of a fixed blade and a rotating blade and having an area where the polymer gel to be crushed remains, it is operated under conditions such that the average residence time is 3 minutes or more. In the step of cutting the polymer gel into fine particles with a diameter of 0.3 to 3 mm, an alkaline substance or an alkaline substance and a compound having or producing active hydrogen are mixed into the resulting finely granulated polymer. The gel is mixed with a paddle-type stirrer coated with a fluorine-containing copolymer resin or equipped with a film made of the copolymer resin, and the paddle shaft installation angle is variable, and the gel is mixed with a paddle-shaped stirrer that is equipped with a fluorine-containing copolymer resin, and the gel is partially hydrated. A method for producing a partially hydrolyzed acrylamide polymer, which comprises decomposition. 2. The manufacturing method according to claim 1, wherein the acrylamide polymer partial hydrolyzate is dried with hot air and powdered. 3. The manufacturing method according to claim 1, wherein a paddle-type stirrer equipped with a film made of a fluorine-containing copolymer resin whose back surface is coated with a light-reflecting metal is used, and ultraviolet rays are irradiated from above. 4. The production method according to claim 1, wherein an alkaline substance or an alkaline substance and a compound having active hydrogen or generating active hydrogen are mixed into the paddle-shaped stirrer.