JPS63270708A - Manufacture of water-soluble cationic (meth)acrylic polymer - Google Patents

Abstract

PURPOSE:To obtain the title polymer having a high molecular weight and a uniform particle size useful as flocculants, by supplying an aqueous solution of a specific monomer, a nonionic surface active agent and an aqueous solution mixture of photopolymerization initiators onto a movable belt, photopolymerizing it and further irradiating the polymer gel sheet thus obtained with light. CONSTITUTION:An aqueous solution (A) having a concentration of 60-80wt.% made up of a cationic (meth)acrylic monomer mixture or a mixture of other water-soluble (meth)acrylic monomer therewith 0.001-1wt.% nonionic surface active agent (B), and a photopolymerization initiator (C) comprising 0.0005-0.03wt.% photopolymerization initiator (a) except a component (b), and 0.0025-0.6wt.% water-soluble azo photopolymerization initiator (b) are homogeneously mixed. The amount of dissolved O2 of the mixed aqueous solution is decreased to 1mg/l or below, and the solution is supplied onto a movable belt in an atmosphere having an O2 concentration of 1vol.% or less and irradiated with light having a dominant wavelength of 300-450nm and intensity of 10-15W/m<2> for 30-40min and then with light having the same wavelength as the former and a light intensity of 20-30W/m<2> for 30-60min. The obtained polymer gel sheet is taken out and irradiated with light having a dominant wavelength of 200-600nm and a intensity of 1,000-2,000W/m<2> for 1-6min in air.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a cationic (meth)acrylic polymer that has good water solubility and is particle-sized.

[Conventional technology]

A wide variety of cationic flocculants are used for the coagulation-sedimentation and clarification treatment of industrial wastewater containing large amounts of organic substances, and for the coagulation-dehydration treatment of mechanical sludge generated by biological treatment of sewage, urine, etc. Of these, (meth)acrylic acid ester-based cationic polymers are most commonly used.

In particular, cationic polymers based on (meth)acrylic acid esters quaternized with benzyl halide are suitable for coagulation and dewatering of sludge containing high concentrations of inorganic salts, and are known to exhibit excellent performance. . A typical example of a (meth)acrylic ester-based cationic polymer quaternized with benzyl halide is benzyl chloride quaternary salt of dimethylaminoethyl methacrylate (methacryloyloxyethyldimethylbenzylammonium chloride).
Polymers include:

When a water-soluble (meth)acrylic polymer is used as a flocculant, its performance is said to be roughly proportional to the molecular weight of the polymer. Moreover, when used for coagulation and dewatering of sludge, etc., mechanical force is applied to filtration and solid-liquid separation is performed, so it is often desirable to form strong flocs. Since high molecular weight polymers are suitable, there is a tendency for more and more high molecular weight polymers to be required.

Although many methods are known for producing water-soluble (meth)acrylic polymers, the aqueous solution polymerization method is the most commonly used method.

This method uses a polymerization initiator that generates radicals by applying thermal energy or by oxidation-reduction reaction to gently proceed with polymerization at a relatively low monomer concentration and at the lowest possible temperature, thereby producing a polymer with a high molecular weight. This is a method to obtain polymers.

Apart from this method, there is also a known method of producing water-soluble polymers by irradiating light or radiation to advance polymerization without using a polymerization initiator that generates radicals by applying thermal energy. There is.

However, in the method using light or radiation, the energy of the light or radiation is very high, so the speed of polymerization is very high, and if the resulting polymer has a high molecular weight enough to be used as a flocculant, It tends to have poor water solubility and has many three-dimensional crosslinks.

On the other hand, if this method is used to obtain a polymer with less three-dimensional crosslinking, the molecular weight of the resulting polymer will be significantly lower, making it unsuitable for applications that require a large, high molecular weight polymer such as a flocculant. The problem is that you can only buy difficult things.

Therefore, in recent years, equipment for light irradiation has become inexpensive and easily available, and although its effective use is desired industrially, high molecular weight water-soluble polymers cannot be used on an industrial scale. At present, very few methods of polymerization by irradiation with light or radiation are used for manufacturing.

[Problem that the invention seeks to solve]

Under these circumstances, the present inventors have conducted extensive studies on polymerization by light irradiation, and have now established a technology for producing high molecular weight water-soluble (meth)acrylic polymers by light irradiation. The production of cationic (meth)acrylic water-soluble polymers with high molecular weight that can be used as flocculants, especially the production of sized particles that can be used as flocculants, has yet to be fully satisfied. Not yet reached.

The present invention has been made to solve the above problem.

[Means for solving problems]

The present inventors first investigated methods for increasing the molecular weight of polymers based on benzyl halide quaternary salts of (meth)acrylic acid aminoalkyl esters, including a method using a thermal radical initiator when polymerizing an aqueous solution, and a method using light irradiation. As a result of repeated research on various methods, it was discovered that the method using light irradiation is the most suitable.

This aqueous solution polymerization method using light irradiation allows the monomer concentration to be as high as 60 to aoy6 (ffiffi%, hereinafter the same), and not only can polymerization be carried out efficiently in a short time, but also has good water solubility and high molecular weight. A benzyl chloride quaternary salt polymer of (meth)acrylic acid aminoalkyl ester is obtained as a hard rubber-like gel-like sheet, but this polymer gel has a unique stickiness.
At the stage of sizing into small-sized particles, the hard rubber-like sheet-like polymer gel easily adheres to the crushing and pulverizing equipment, and the pulverized particles adhere to each other, and the nonionic surfactant , addition to the polymer such as polyethylene glycol,
It has been found that even if measures such as coating and spraying are taken, it is not possible to sufficiently suppress adhesiveness and adhesion to achieve good workability.

In addition, the hardness of this hard rubber-like sheet-like polymer gel changes markedly due to slight differences in temperature.
A piece of the polymer kept at a temperature of ℃ (!00 mm x 100 m
m x 10 mm) does not exhibit adhesiveness and is so hard that it cannot be bent by hand, but at 35°C it adheres to the polyethylene film and becomes difficult to peel off, and becomes flexible enough to be easily bent by hand. show.

In the production of benzyl chloride quaternary salt-based polymers of (meth)acrylic acid aminoalkyl esters, the development of tackiness and adhesion due to thermoplasticity is particularly problematic because hard rubber-like sheet-like polymer gels are thinned. Even if the product is cooled with cold air, the temperature will inevitably rise to about 4°C due to the heat generated during the process, and the particles in the process of being granulated will adhere to each other. , caking, which places an excessive load on the vertical cutter and prevents it from achieving its required performance. In addition, even in the initial stage of drying, the crushed and finely divided particles are heated in the dryer and adhere to each other.
This means that the drying rate becomes so-called agglomerated and the drying rate is significantly reduced.

Such thermoplasticity is also observed in methyl chloride quaternary salt polymers of (meth)acrylic acid aminoalkyl esters, but it is not so large that handling is a problem, and the tackiness, adhesion, and adhesion are also low. This is to the extent that there is no problem with workability.

Therefore, the present inventors have conducted extensive research in an attempt to solve the above problems by copolymerizing the monomers that are the raw materials for these polymers at high concentrations under specific conditions and making the resulting polymer gel fine. , we have completed the present invention.

The present invention provides particle-sized cation particles obtained by polymerizing an aqueous solution of a cationic (meth)acrylic motumer mixture or a mixture of the cationic (meth)acrylic monomer mixture and other water-soluble (meth)acrylic monomers. (meth)acrylic water-soluble polymer, (ω) total monomer content is 60 to 80%, and pl+
is 4 to 7 and (c) one or more nonionic surfactants in an amount of 0.001 to 1% based on the total monomer amount and (c) water-soluble based on the total monomer amount. Photoinitiator (A) other than azo photoinitiator (B) 0.0005-0.03% and water-soluble azo photoinitiator (B) 0.0025-0
．． After reducing the amount of dissolved oxygen in the mixed aqueous solution to 1 mg/g or less,
It is supplied to a thickness of 3 to 18 mm onto a movable belt in an atmosphere where the oxygen concentration in the gas phase is 96 or less per volume, and the main wavelength is added to the mixed aqueous solution on the movable belt as a first stage. 300~450nrs s Light intensity lO~15
W/rrl", irradiation time 30-60 minutes, main wavelength 300-450 nm as the second stage, light intensity 20-30 W/r
After performing at least two stages of light irradiation with an irradiation time of 30 to 60 minutes, ■ The hard rubber-like polymer gel sheet that has been polymerized is continuously taken out from the movable belt, and the polymer gel sheet is Main wavelength in air: 200 ~ [ioo 1111
% light intensity 1000-2000 W/rrf' light 1
After ~6 minutes of irradiation, ■ the polymer concentration of the hard rubbery polymer gel sheet was 6.
While maintaining the polymer concentration at 0 to 85%, it is further crushed into square pieces of 3 to 18 mm using a roller type cutter, and then, while maintaining the polymer concentration at 60 to 85%, it is crushed to 0. The present invention relates to a method for producing a cationic (meth)acrylic polymer having good water solubility and sized particles, which comprises refining the particles to a size of 3 to 3 and then drying with hot air.

〔Example〕

The cationic (meth)acrylic monomer mixture used in the present invention has the general formula (1): [wherein R1 is a hydrogen atom or a methyl group, R2 and R
3 is an alkyl group having 1 to 4 carbon atoms, R2 and R3
may be the same as the general formula (■): Hydrogen atom or methyl group, R5 and R
6 is an alkyl group having 1 to 4 carbon atoms, and R7 is a hydrogen atom or an alkyl group having 1 carbon number, such as a methyl group or an ethyl group.
The alkyl group 1, Ze of ~3 is an acid residue (halogen anion, monoalkyl sulfate anion or anion derived from a mineral acid), preferably CI, Or, CH3SO
4C1e C2H5SO4, (SO4-″″) / 2, n is 1
is an integer of ~4].

Specific examples of the monomer represented by the general formula (I) include N-acryloyloxyethyl-N, N-
Dimethyl-N-benzylammonium salt (chloride,
bromide), N-methacryloyloxyethyl-N,
N-dimethyl-N-benzylammonium salt (chloride, bromide), etc., and specific examples of the compound represented by the general formula [1 salt, sulfate), N-methacryloyloxyethyl-N, N
-dimethylamine salt (hydrochloride, sulfate), N-methacryloyloxyethyl-N, N-diethylamine salt (hydrochloride, sulfate), N-methacryloyloxyethyl-N,
N, N-trimethylammonium salt (chloride, monomethyl sulfate), N-acrylokydiethyl-N,
N, N-) Limethylammonium salt (chloride, monomethyl sulfate), X-methacryloyloxyethyl-N
, N-diethyl-N-methylammonium salt (chloride, monomethyl sulfate), and the like.

The monomer represented by the general formula (1) and the general formula (II
) The mixing ratio with the monomer represented by (1)
/(II) is preferably in a molar ratio of 20/80 to 80/20.

The cationic (meth)acrylic monomer mixture used in the present invention may be polymerized alone, or this mixture may be mixed with other water-soluble (meth)acrylic monomers and polymerized.

Examples of the other water-soluble (meth)acrylic monomers include acrylamide, methacrylamide, derivatives thereof, acrylic acid, methacrylic acid, alkali metal salts, ammonium salts, amine salts thereof, and acrylamide-2-methylpropanesulfonic acid. and its salt. Furthermore, even with hydrophobic monomers other than these, such as alkyl esters of (meth)acrylic acid and (meth)acrylonitrile, a uniform monomer aqueous solution can be obtained, and the resulting hard rubber-like polymer gel sheet has good tackiness and adhesion. It can be used as long as the water-solubility of the resulting polymer is not impaired. These may be used alone or in combination of two or more.

The proportion of the cationic (meth)acrylic monomer mixture and other water-soluble (meth)acrylic monomers cannot be determined unconditionally depending on the types of monomers used, but it is possible to use the general formula ( The ratio of the monomer represented by II) in the aqueous monomer solution is 5% or more, in order to achieve thermoplasticity and a thermoplastic state that the polymer constituting the rubber-like polymer gel sheet obtained essentially has. It is preferable from the first point of view that it is possible to keep the tackiness low and to reduce the tackiness and adhesion to equipment for crushing, pulverization, etc., and the adhesion of polymer gels to each other. Furthermore, the monomer represented by the general formula (1) alone is hard and brittle, which compensates for the drawbacks of finely divided dried products that tend to lead to the generation of fine powder, and also makes the polymerization operation by a series of light irradiation described below more effective. It is also preferable from the point of view of making it easy to increase the molecular weight.

The concentration of the monomer aqueous solution used in the present invention is 60 to 80%, preferably 70 to 80%, from the viewpoint of maintaining high quality of the polymer and making the resulting polymer gel into fine particles. ranges from 4 to 7. Generally, as the monomer concentration increases, three-dimensional reticulation reactions are more likely to occur, and in addition, when attempting to obtain a polymer that is completely water-soluble, the degree of polymerization generally decreases. However, when the polymer is produced by the method of the present invention, a water-soluble high molecular weight polymer is obtained which can be used as a flocculant.

A nonionic surfactant is added to the monomer aqueous solution in the present invention in an amount of o,oot to 1% based on the total amount of monomers. Preventing the decrease in water solubility due to crosslinking reaction in the polymer obtained by adding a nonionic surfactant, that is, the formation of a water-insoluble polymer,
In addition to being able to contain polymers with high molecular weight and good water solubility, the polymer gel can be easily taken out from the polymerization container, and the stickiness characteristic of polymer gels can be reduced, and the mutual adhesion of polymer gels can be reduced. can be lowered.

Specific examples of the nonionic surfactant include polyethylene glycol alkyl phenyl ether (especially polyethylene glycol distyrenated phenyl ether), polyethylene glycol alkyl ether, polyethylene glycol fatty acid ester, polyethylene glycol sorbitan fatty acid ester, polyethylene glycol-polybroin, etc. Examples include nonionic surfactants such as birene glycol block copolymers, and these may be used alone or in combination of two or more.

If the amount of the nonionic surfactant is less than 0.001%, the initial purpose will not be achieved, and if it exceeds 1%, the surfactant will act as a chain transfer agent, resulting in a decrease in the molecular weight of the resulting polymer. becomes extremely low, making it impossible to convert the high molecular weight polymer targeted by the present invention.

The nonionic surfactant may be used in combination with one or more of hypophosphites, urea compounds, and aliphatic tertiary amines.

By using these compounds together with a nonionic surfactant, the water solubility of the resulting polymer can be improved, that is, the crosslinking reaction in the polymerization reaction can be prevented, and the resulting polymer can be improved. Intermolecular and intramolecular crosslinking reactions can be prevented during the step of crushing and drying the gel. Good results can be obtained by adding only a nonionic surfactant, but even better results can be obtained by using a hypophosphite, an aliphatic tertiary amine, or a urea compound in combination.

Specific examples of the above-mentioned hypophosphites include sodium hypophosphite, potassium hypophosphite, ammonium hypophosphite, and the like. It may also be an amine salt of hypophosphorous acid.

Specific examples of the urea compounds include urea, thiourea, ethylene urea, and ethylene thiourea, and specific examples of the aliphatic tertiary amines include trimethylamine, triethylamine, dimethylethylamine, methyldiethylamine, triethanolamine, and the like. Examples include methylgetanolamine, dimethylethanolamine, and ethylgetanolamine.

Next, regarding the blending amount of these compounds, in the case of hypophosphite, it is relative to the total monomer amount.

It is preferably from 0.001 to 5.0%, and in the case of aliphatic tertiary amines and urea compounds, it is preferably o, oot to 5,096, respectively, based on the total monomer amount.

In the polymerization of the monomer aqueous solution in the present invention, 0.0005 to 0.03% of the photopolymerization initiator (A) and 0.0025 to 0.6% of the total monomer amount, preferably 0.
．． 005-0.45% water-soluble azo photoinitiator (B
) is mixed with an aqueous monomer solution, dissolved substantially uniformly, and used as a photopolymerization initiator.

The photopolymerization initiator (A) and the water-soluble azo photopolymerization initiator (
The usage ratio with B) is (A)/(13
)-115 to 1120, preferably 1110 to 1
/15 is more preferable.

Specific examples of the photoinitiator (A) include compounds such as benzyl, benzophenone, benzoin, benzoin alkyl ether, benzoin hydroxyalkyl ether, and anthraquinone, which may be used alone. Two or more types may be used in combination.

Specific examples of the water-soluble azo photopolymerization initiator (B) include 2,2-azobis(2-N-phenylaminoamidinopropane), 2,2°-azobis(N,
Compounds such as N'-dimethyleneisobutyramidine), 2,2'-azobis(2-amidinopropane) and their mineral acid salts, 4,4-azobis(4-cyanovaleric acid) and its salts (alkali metal salts) , ammonium salt, amine i>
, 2-(carbamoylazo)isobutyronitrile, 2.
2'-Azobis(isobutyramide) and its hydrates, 2
, 2°-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide), 2.2'-Azobis[
2-Methyl-N-(1,1-bis(hydroxymethyl)
ethyl)propionamide), 2,2'-azobis[
2-Methyl-N-(1,1-bis(hydroxymethyl)
-2-hydroxyethyl)propionamide], and these may be used alone or in combination of two or more.

By carrying out photopolymerization using a mixture of the photopolymerization initiator (A) and the water-soluble azo photoinitiator (B), the photopolymerization initiator (A) or the water-soluble azo photopolymerization initiator (B) is
) It is possible to easily produce a polymer with a significantly higher molecular weight than when each of the above is used alone.

In the method of the present invention, the amount of dissolved oxygen in the mixed aqueous solution containing the monomer aqueous solution in the polymerization step has an extremely important effect on the polymerization reaction, so the amount of dissolved oxygen in the mixed aqueous solution must be kept below Img/N. . When the amount of dissolved oxygen exceeds 1 a+g/D, problems such as unpolymerized portions occurring and the degree of polymerization not improving occur.

Therefore, the amount of dissolved oxygen in the mixed aqueous solution must be kept below 1 mg/fl prior to the polymerization reaction. Examples include a method of introducing the oxygen into an aqueous solution, and a preferred method is a method of introducing an inert gas into a seven-mer aqueous solution to reduce the amount of dissolved oxygen.

In the method of the present invention, it is necessary to limit not only the amount of dissolved oxygen in the mixed aqueous solution but also the amount of oxygen in the gas phase at the location where the photopolymerization reaction is carried out for the same reason as in the case of dissolved oxygen. % or less.

The mixed aqueous solution prepared in this way is placed on a movable belt in an atmosphere where the oxygen concentration in the gas phase is 1% by volume or less.
After being supplied to a thickness of ~18 mm, 1 stage 1
] as main wavelength 300~450na+, light intensity 10
~15W/rf, irradiation time 30-00 minutes, preferably 3
0-40 minutes, main wavelength 300-450r+ as second stage
m s light intensity 20-30 y/y, preferably 20-25
W/rr? , irradiation time 30 to fiO minutes, preferably 30
Polymerization is carried out by performing at least two stages of light irradiation for ~40 minutes.

The light source used in the present invention is not particularly limited, and any light source that can emit light of a predetermined intensity with a main wavelength of 300 to 450 nm can be used. In addition to lamps, halogen lamps, and carbon arc lamps, high-pressure mercury lamps and low-pressure mercury lamps are also used.

When polymerizing according to the method of the present invention, it is preferable to cool with water or cold water in order to completely remove the heat of reaction.

Generally, the higher the light intensity, the faster the polymerization reaction, but the lower the molecular weight of the resulting polymer. In addition, since the pre-illumination time during polymerization has a close relationship with the light intensity,
It is necessary to adjust the light intensity and irradiation time appropriately depending on the degree of polymerization of the desired polymer. Therefore, in order to obtain a predetermined high molecular weight polymer, the light intensity and irradiation time must be carefully considered and set.

In the method of the present invention, the reason for carrying out at least two stages of light irradiation under the above specific conditions is based on such considerations. A) and a water-soluble azo photopolymerization initiator (B
), that is, the increase in the molecular weight of the polymer is promoted. In this way, it becomes easy to obtain the polymeric robolimer, which is the object of the present invention.

The polymer gel obtained by polymerization under the above polymerization conditions is removed from the movable belt.

The obtained polymer gel is essentially a hard rubber-like polymer gel sheet with high stickiness, but in the present invention, a nonionic surfactant is used to suppress stickiness. Removal from the belt is facilitated continuously by peeling.

When the movable belt used in the present invention is coated with a tetrafluoroethylene-ethylene copolymer, the polymer gel produced from the movable belt can be removed very easily by peeling. In addition, by covering the movable belt with a tetrafluoroethylene-ethylene copolymer film that has a metal-steamed back surface, the irradiated light can be used more effectively and the polymerization reaction can be accelerated. Can be done.

The polymer gel, which is continuously removed from the movable belt, has a light intensity of 1,000 in the main wavelength of 200-600 nm in air.
~2,0OOV/rd (7) Light power 1-6 minutes,
Irradiation is preferably performed for 1 to 3 minutes.

By this light irradiation, unreacted residual monomers scattered in the polymer gel are reduced to a value below a required level. Moreover, the heat generated by this light irradiation also raises the temperature of the polymer gel to, for example, 80 to 110°C, contributing to the reduction of unreacted residual monomers. In addition, the temperature rise of the polymer gel due to light irradiation in the air is not actually a problem because it is easily cooled down by a short period of cold air before the polymer gel is crushed by the crusher. The effect of reducing the moisture present on the surface and preventing the finely divided polymer gels from adhering to each other after crushing can be obtained.

Note that there is no possibility that the post-irradiation will cause undesirable three-dimensional crosslinking in the polymer gel and deteriorate its water solubility, and the water solubility will not be impaired. However, if the light irradiation time is longer than 6 minutes, the polymer gel will be easily colored and the molecular weight of the polymer will be excessively lowered, which is not preferable. It is preferable to limit the irradiation to 1 to 3 minutes to minimize the decrease in the molecular weight of the polymer.

Before or after this light irradiation, the polymer gel sheet may be left under hot air at 50 to 120° C. for up to 5 minutes to modify the sheet surface.

When a cationic (meth)acrylic monomer mixture having the above-mentioned concentration or a mixed aqueous solution mainly composed of the mixture is polymerized, a polymer gel with no fluidity and hardness or high elasticity is obtained. Therefore, for example, if you try to volatilize the water contained in the polymer gel without mechanically crushing it, you will have to leave it at high temperatures for a very long time, and as a result, The molecular weight of the high-molecular-weight polymer that has been painstakingly produced may decrease, or crosslinking of the polymer may be accelerated by heat, resulting in a significant reduction in commercial value.

Therefore, a method is generally adopted in which the obtained polymer gel is crushed into fine particles by some mechanical means and then dried by heating to remove water.

Generally, a method is widely used in which a polymer gel obtained by polymerization is formed into a strand using an extruder such as a meat grinder, and then heated and dried. However, when using an extrusion molding machine such as a meat grinder, especially if the polymer gel is extremely hard, not only will the friction with the machine wall be large, reducing efficiency, but the polymer itself will also experience friction. This is not a very preferable method because heat, physical force, etc. can cause molecules to break and cause deterioration, such as a decrease in molecular weight.

The present invention is a combination of manufacturing methods for obtaining finely granulated polymers that do not deteriorate due to frictional heat or physical forces.

For example, the polymer gel described in JP-A-81-110510 is fed from above into a crusher and is cut by a pair of roller-type cutters that rotate in an interlocking direction to form, for example, short strands. Ru. In addition, the polymer gel is continuously supplied to the roller cutter using a method such as a method in which the polymer gel is continuously taken out from the other end of a movable support, such as an endless belt, and then fed into the roller cutter. The process can be made continuous and production efficiency can be improved. For example, a polymer gel strand cut into strips is cut by a rotating blade and a fixed blade provided on the outer periphery of a rotating body into strips, preferably rectangular strips with an average particle size of 3 to 18 m+s. be made into The polymer concentration at this time is 60-8
It is maintained at 5%. If the polymer concentration is lower than this range, it will be difficult to crush it into a predetermined square shape, and if it is higher than this range, the polymer gel will become extremely hard and the load on the machine will be large. , it becomes impossible to crush continuously. In addition, it is necessary to maintain water solubility and to maintain the molecular weight within this range in order to prevent a decrease in molecular weight.

The thus obtained 3-18 am angular polymer gel is
A vertical cutting machine, for example, the device described in JP-A No. 61-110511, can cut the polymer at a concentration of 60 to 85%.
While maintaining the same size, the particles are refined to a diameter of 0.3 to 3 mm.

The features of the structure of the cutting machine are that the gap between the vertical fixed blade and the rotary blade installed vertically inside the cutting machine can be adjusted, the hole diameter of the sieve can be changed, and several machines can be pulled in series. By arranging a vertical cutting machine and passing the cutting machine two to several times, it is possible to control the residence time required for pulverization, and it is possible to control the residence time required for pulverization, and even to a polymer gel with a small particle size, for example, 1 mmφ or less. The point is that it is easy to cut. Furthermore, a polymer gel having a small particle size such as 1 mmφ or less has a favorable effect of approaching a spherical shape.

When such a method is adopted, almost no dust is generated during the step of refining the polymer gel, which is in a wet state, and the particle size distribution can be changed to a uniform particle size, which is close to monodisperse. .

Therefore, the normally employed process, that is, the step of drying the polymer gel and then pulverizing and sizing it, becomes unnecessary.

One of the features of the present invention is that a method is adopted in which a polymer gel containing a large amount of water is made into fine particles as it is, and by adopting this method, it is possible to achieve good water solubility and particle size for the first time. A high molecular weight cationic (meth)acrylic polymer is obtained.

When crushing a polymer gel into fine particles, in order to increase the cutting efficiency and prevent re-adhesion of the resulting fragmented polymer gel and the finely divided polymer gel, It is preferable to keep the temperature of the polymer gel as low as possible during cutting.

Methods for lowering the temperature of the polymer gel include cooling sufficiently during the polymerization stage when crushing it into small pieces, and forcing the polymer gel obtained by polymerization by using cold air etc. before crushing it in a crusher. This can be achieved by a method of cooling to a high temperature, a method of blowing cold air during pulverization, etc., but the temperature is usually adjusted to 20 to 40°C, preferably 30°C or less.

In addition, during crushing and pulverization processing, if necessary, polyethylene glycol, nonionic surfactants, etc. may be added to the crusher or vertical cutting machine, or applied to the surface of the polymer gel or the surface of the crushed polymer gel. It may also be possible to prevent the redeposition of the fragmented polymer gel or finely granulated polymer gel.

The thus finely granulated polymer gel is usually dried by a known method, for example, with hot air on a ventilated belt, to obtain a granular material having a moisture content of 10% or less.

In the production method of the present invention, as described above, there is almost no need to further crush or size the powder or granules, but a crushing/sizing process may be employed if necessary.

The molecular weight of the obtained polymer was high, and the viscosity of the salt solution [a solution of 4% saline with a polymer concentration of 0.5% was prepared using a Brookfield viscometer, rotor No. 1, and rotation speed 60 rpm.
a+, viscosity measured at 25°C] is high, has good water solubility, and is a well-sized cationic (meth)acrylic polymer.

Next, the manufacturing method of the present invention will be specifically explained based on Examples.

Examples 1 to 3 and Comparative Examples 1 to 6 In a chamber completely filled with nitrogen gas and in which the oxygen concentration in the gas phase is 1% by volume or less, a stainless steel medium 450 mm,
For polymerization, an endless belt with an effective length of 3,000 mm is equipped with a polytetrafluoroethylene-ethylene copolymer film whose back side is vapor-deposited with aluminum, and has a structure that allows hot to cold water to be sprayed onto the endless belt from below. The belt was installed as a movable support, driven at a constant speed of 501/min, and water at 15° C. was sprayed from below the belt. In addition, a low-pressure mercury lamp was installed as a light irradiation source on the upper part of the movable support, and a stainless steel endless belt of 1.5
The main wavelength 300-450 nm light emitted from a low-pressure mercury lamp with a light intensity of 15 W/rrf was applied to the 00 mm section, and the main wavelength 300-450 nm section of the remaining stainless steel endless belt was irradiated with the main wavelength 300-450 nm light.
No+, light with a light intensity of 25 W/i was irradiated.

Next, the additive-containing monomer aqueous solution shown in Table 1 after removing deionized water was blended, and after adjusting pl+, deionized water was added so that the total amount was 40.000 f, and the additive-containing monomer aqueous solution was mixed. was prepared.

Nitrogen gas is blown into about 40 fl of this additive-containing monomer aqueous solution to reduce the amount of dissolved oxygen to 1a+g/II or less, and a metering pump is used to pump it onto one end of the belt in the driving state.
Polymerization was carried out by supplying at a rate of 3.5 N/hour and irradiating light.

In the flow path immediately before the additive-containing monomer aqueous solution is fed onto the belt, a photopolymerization solution prepared in advance to have the composition shown in Table 2 and stored in a storage tank (5Ω capacity) with a stirrer installed separately. The initiator solution was added at 30.4 g/hour in the case of the additive-containing monomer aqueous solution 1, 20.3 g/hour in the case of the additive-containing monomer aqueous solution 2, and in the case of the additive-containing monomer aqueous solution 3. was added at a rate of 18.9 g/hour, mixed uniformly, and used as a mixed aqueous solution.

The time during which the mixed aqueous solution was polymerized on the belt was 60 minutes, and the thickness of the mixed aqueous solution was 10III1. 60 minutes after the start of supply of the mixed aqueous solution, a sheet of polymer gel having a thickness of about 10 mm and a temperature of about 20° C. was exchanged from the other end of the endless belt. The obtained polymer gel was in a state where it could be easily peeled off manually from the belt surface, and continuous polymerization for about 3 hours was possible.

After the polymer gel sheet continuously obtained from the other end of the endless belt is continuously taken out into the air, the main wavelength 2
Light with a light intensity of 1.900 W/d emitted from a high-pressure mercury lamp of 00 to BOOr+m was irradiated for about 2.0 minutes.

At this time, the surface temperature of the polymer gel sheet rose to about 80°C. Thereafter, the polymer gel sheet was immediately cooled by blowing cold air at 15°C, and then fed to a crusher as exemplified in JP-A No. 131-110510.
m x 10 mm (7) angular polymer gels were obtained.

Then, while blowing cold air at about 15°C, the particles were reduced to fine particles using a vertical cutting machine as shown in Japanese Patent Application Laid-Open No. 110511/1983 equipped with a screen of about 3 mm diameter, and then cut into particles of about 2 mm diameter.
It is cut through a cutting machine equipped with a mmφ screen and an approximately IIIIIIφ screen in this order.
A finely granulated polymer gel with a uniform diameter of amφ was obtained. The resulting finely granulated polymer gel with a diameter of approximately 1 am was dried at 80°C in a ventilated band type dryer.
Powder with a moisture content of 10% or less was changed in 3 minutes. The obtained powder and granules were sized to approximately 0.9 mmφ, the aqueous solution did not contain any water-insoluble substances, and the salt solution viscosity of the obtained powder and granules was as shown in Table 3. .

[Margin below]

In addition, in comparative examples that were the same as the examples except that the monomer used was methacryloyloxyethyldimethylbenzylammonium chloride alone, the resulting polymer gels were highly sticky and were crushed by the rotating blades of the crusher. Because polymer gel pieces adhere, the crusher must be stopped every 15 to 20 minutes to remove them, and vertical cutters equipped with a screen of approximately 1 diameter require intermittent motion. was forced to.

Furthermore, the finely divided polymer gel has great mutual adhesion and becomes lumpy, so in order to reduce the water content to 10% or less, it is necessary to
It took 5 minutes.

Although the thus obtained polymer had good water solubility, it did not dissolve in a saline solution and the viscosity of the salt solution could not be measured.

[Effects of the Invention] When a cationic (meth)acrylic polymer is produced by the method of the present invention, a polymer with a high molecular weight that is used as a flocculant and has good solubility in saline water as well as water can be finely produced. It can be obtained as a granulated powder.

Claims (1)

[Claims] 1. Polymerization of an aqueous solution of a cationic (meth)acrylic monomer mixture or a mixture of the cationic (meth)acrylic monomer mixture and other water-soluble (meth)acrylic monomers to form particles. (1) (a) The total monomer content is 60 to 80% by weight,
and a monomer aqueous solution with a pH of 4 to 7; (b) one or more nonionic surfactants in an amount of 0.001 to 1% by weight based on the total amount of monomers; and (c) water-soluble based on the total amount of monomers. photopolymerization initiator (A) other than the azo photopolymerization initiator (B) 0.0005 to 0.0
3% by weight and water-soluble azo photoinitiator (B) 0.0
After reducing the amount of dissolved oxygen in the mixed aqueous solution to 1 mg/l or less, an atmosphere in which the oxygen concentration in the gas phase is 1% by volume or less is prepared. (2) The mixed aqueous solution on the movable belt is supplied with a main wavelength of 300 to 450 nm and a light intensity of 10 to 15 W as the first stage.
After performing at least two stages of light irradiation under the following conditions: m^2, irradiation time 30 to 60 minutes, second stage with main wavelength 300 to 450 nm, light intensity 20 to 30 W/m^2, and irradiation time 30 to 60 minutes. (3) The polymerized hard rubber-like polymer gel sheet is continuously taken out from the movable belt, and the polymer gel sheet is heated in air with a main wavelength of 200 to 600 nm and a light intensity of 1000 to 2000 W/m^2. (4) While maintaining the polymer concentration of the hard rubber-like polymer gel sheet at 60 to 85% by weight, crush it into 3 to 18 mm square pieces with a roller cutter. 5) Next, while maintaining the polymer concentration at 80 to 85% by weight, the particles are finely pulverized to a diameter of 0.3 to 3 mm using a vertical cutter, and then (6) dried with hot air to ensure good water solubility. A method for producing a cationic (meth)acrylic polymer that is also particle-sized. 2 The cationic (meth)acrylic monomer mixture has the general formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (wherein R^1 is a hydrogen atom or a methyl group, R^2 and R^3 is an alkyl group having 1 to 4 carbon atoms, and R^3 is an alkyl group having 1 to 4 carbon atoms.
2 and R^3 may be the same, X^■ is a halogen anion, m is an integer of 1 to 4) and general formula (II): Yes▼(II) [In the formula, R^4 is a hydrogen atom or a methyl group, R^5 and R^6 are each an alkyl group having 1 to 4 carbon atoms, and R^
5 and R^6 may be the same, R^7 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Z^■ is an acid residue (derived from a halogen anion, a monoalkyl sulfate anion, or a mineral acid). n is an integer from 1 to 4], and the proportion of monomers represented by general formula (I) and general formula (II) is (I)/( II) = 20/80 to 80/20, and the monomer represented by general formula (II) is present in an aqueous monomer solution at least 5% by weight, and the other water-soluble (meth)acrylic monomer is (meth)acrylamide. , (meth)acrylonitrile, (meth)acrylic acid, and water-soluble salts thereof. 3. Claims in which the nonionic surfactant is at least one selected from polyethylene glycol alkyl phenyl ether, polyethylene glycol alkyl ether, polyethylene glycol fatty acid ester, polyethylene glycol sorbitan ester, and polyethylene glycol-polypropylene glycol block copolymer. The manufacturing method described in paragraph 1. 4. The method according to claim 3, wherein the polyethylene glycol alkyl phenyl ether is polyethylene glycol distyrenated phenyl ether. 5. The manufacturing method according to claim 1, in which at least one of hypophosphites, aliphatic tertiary amines, and urea compounds is used in combination with a nonionic surfactant. 6. The method according to claim 1, wherein the photopolymerization initiator (A) is at least one selected from benzoin, benzoin alkyl ether, benzoin hydroxyalkyl ether, benzyl, benzophenone, and anthraquinone. 7 The water-soluble azo photoinitiator (B) is 2,2'
-Azobis(2-amidinopropane), its mineral acid salt, 2
, 2-azobis(N,N'-dimethyleneisobutyramidine), its mineral acid salt, 4,4'-azobis(4-cyanovaleric acid), its alkali metal salt, ammonium salt, amine salt, 2-(carbamoyl The method according to claim 1, wherein at least one selected from azo)-isobutyronitrile and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] is used. 8. The method of claim 1, wherein the movable belt is coated with a tetrafluoroethylene-ethylene copolymer film having a metalized backside. 9 The conditions for the light irradiation are such that the main wavelength is 300 as the first stage.
~450nm, light intensity 10~15W/m^2, irradiation time 30~60 minutes, main wavelength 300~450n as the second stage
m, light intensity 20-25W/m^2, irradiation time 30-60
The manufacturing method according to claim 1, wherein the manufacturing method is as follows. 10. The manufacturing method according to claim 1, wherein the movable belt is cooled with water or cold water from the lower part of the movable belt during light irradiation. 11. The manufacturing method according to claim 1, wherein the rubber-like polymer gel sheet taken out from the movable belt is left under hot air at 50 to 120° C. for less than 5 minutes to modify the surface of the sheet. 12. The manufacturing method according to claim 1, wherein a nonionic surfactant, polyethylene glycol, or an aqueous solution thereof is applied to the surface of the rubbery polymer gel sheet. 13. The manufacturing method according to claim 1, wherein cold air is blown during the granulation using the vertical cutter. 14 Salt solution viscosity of the cationic (meth)acrylic polymer with good water solubility and sized particles [a solution of 4 wt% saline with a polymer concentration of 0.5 wt% using a Brookfield viscometer, Rotor no. 1. Number of revolutions 60
viscosity measured at rpm, 25°C] of at least 10 cP
The manufacturing method according to claim 1.