JPS61155406A - Production of high-mw acrylic polymer - Google Patents

Abstract

PURPOSE:To obtain the title polymer, by adding a nonionic surfactant, an anionic surfactant and a photopolymerization initiator to an aqueous solution of an acrylamide monomer or its mixture with a water-soluble vinyl monomer and polymerizing the monomer by irradiation with ultraviolet rays in a specified oxygen atmosphere. CONSTITUTION:The desired high-MW acrylic polymer is obtained by polymeriz ing an aqueous solution of an acrylamide monomer or its mixture with other water-soluble vinyl monomers under the following conditions. Said aqueous solution is fed to a movable belt and irradiated with ultravoilet rays under conditions including a total monomer concentration in said aqueous solution of 20-45wt%, a pH of 4-7, an amount of a nonionic surfactant and an anionic surfactant of 0.001-1wt% based on monomer, a dissolved oxygen concentration in the aqueous solution of 1mg/1 or below, an amount of a photomerization initiator of 0.03wt% or below based on the monomer and an oxygen content in the vapor phase of 1vol% or below. The formed rubber-like layer polymer sheet is continuously withdrawn from the movable belt, finely pulverized and dried with hot air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a high-molecular-weight acrylamide polymer having good water solubility and sized particles by irradiation with light energy.

Acrylic water-soluble polymers, especially water-soluble polymers mainly composed of acrylamide, are used as paper strength agents, binders, wastewater purifiers,
Widely used as an ore sedimentation agent. In particular, its use as a flocculant for various industrial wastewaters has been rapidly increasing in recent years as one of the countermeasures against environmental pollution.

When a water-soluble polymer is used as a flocculant, its performance is generally said to be proportional to the molecular weight of the polymer, and there is a tendency for higher molecular weights to be required.

Methods for producing water-soluble acrylic polymers include bulk polymerization, suspension polymerization, emulsion polymerization, and (aqueous) solution polymerization, but polymers with a high molecular weight that can be used as a flocculant are polymerized in an aqueous solution system. It is most common to do so.

The most common method for obtaining high molecular weight polymers in an aqueous solution system is to use an initiator that generates radicals by thermal energy or a redox initiator consisting of a peroxide and a reducing substance, and use a relatively low u layer weight. This is achieved by allowing the polymerization to proceed slowly at the lowest possible temperature and at a low concentration.

An initiator that generates radicals using thermal energy.
Examples of methods for proceeding with polymerization include a method using light (ultraviolet rays, visible light) energy, a method using radiation energy, and a method of proceeding polymerization under high pressure. For example, JP-A-46-2094 According to publications, it is known to produce water-soluble polymers by subjecting an aqueous solution of an ethylenically unsaturated monomer to radiation polymerization. Since this is very large, the speed of polymerization is very high, and as a result, the molecular polymerization (grafting) of the monomers is promoted, and the resulting polymer has a rich three-dimensional network structure. Therefore, it tends to become a so-called water-insoluble polymer.

Furthermore, even if a polymer with a small three-dimensional network structure could be obtained, the molecular weight of the polymer would be extremely small and would not be suitable at all for applications requiring a high molecular weight such as flocculants.

For this major reason, there are currently almost no examples of methods for producing high molecular weight polymers using light or radiation energy being employed on an industrial scale.

However, light or radiation energy can accelerate polymerization very quickly.

For example, a '+1 star body aqueous solution usually contains a polymerization inhibitor, etc., and is kept in liquid form, but if a considerable amount is mixed in, it will not easily polymerize with thermal energy, but when irradiated with light energy, it will become extremely difficult to polymerize. It causes a one-coupling reaction in a short time.

Particularly in the field of light energy, in view of the fact that in recent years it has become possible to produce such devices at low cost and by hand, the effective use of light energy is highly desirable from an industrial perspective.

It also has several characteristics compared to conventional polymerization methods that utilize thermal energy. In other words, since the polymerization rate is extremely high, the polymerization time is greatly shortened and productivity is improved, and the reaction rate of the monomer is greatly increased, so the current situation is that the toxicity of the monomer is being raised. From this point of view, it is easy to lead to zero pollution.

In terms of equipment, it has the advantage of being very compact since continuous and short-term reactions are possible.

Therefore, if we can improve the polymerization technology using light energy irradiation, suppress or prevent the formation of the three-dimensional network structure, and develop a technology that can increase the molecular weight, it will greatly contribute to industrial progress.

As a result of intensive research into polymerization by irradiation with high light energy according to the present invention, we have not only been able to solve these problems, but also reached a point where the polymerization technology can be fully adopted industrially. We confirmed that the polymerization mechanisms of light irradiation polymerization and thermally initiated polymerization are completely different, and that the favorable factors for thermally initiated polymerization are not necessarily the favorable factors for light energy irradiated polymerization.As a result of our efforts to develop various technologies, we developed this book. This invention has been achieved. That is, the present invention provides (1),
In a method for producing a water-soluble polymer by polymerizing an aqueous solution of acrylamide monomer or other water-soluble vinyl monomers, a) the total amount of monomers in the monomer aqueous solution is 20 to 20%.
45 wt%, b) nonionic surfactant, anionic surfactant 1
species or two or more species into the monomer aqueous solution, each at 0.0
01 to 1 wt% (based on the monomer), C) the dissolved oxygen in the monomer aqueous solution is 1 mg/l or less, and then, d) a photopolymerization initiator is added to the monomer aqueous solution.

Add 3wt% or less/monomer and mix uniformly.

e) After that, the above a) to d) are placed on a movable belt in an atmosphere where oxygen in the gas phase is 1 vol% or less.
f) Supply the monomer aqueous solution prepared in step 1 to a thickness of 3 to 10 mm;
0~450mg, 50W/rrr' or less ultraviolet rays
Irradiate for ~90 minutes.

g) The rubbery layered polymer sheet with a thickness of 3 to 10 mm is then continuously removed from the movable belt, and h) The rubbery layered polymer sheet is maintained at a polymer concentration of 20 to 60 wt%. i) Then, while maintaining the polymer concentration at 20 to 60 wt%, the particles were crushed to a diameter of 0.3 to 3 mm using a vertical cutting machine. , j) consists of hot air drying, has good water solubility, and! The present invention provides a method for producing a high molecular weight acrylic polymer formed into one grain.

Monomers used in this application include acrylamide, methacrylamide and their derivatives, acrylic acid, methacrylic acid and their alkali metal salts, amine salts, acrylamide-2-methylpropanesulfonic acid and its salts, vinylsulfonic acid and its salts.

Furthermore, other monomers such as esters of (meth)acrylic acid such as alkyl esters of (meth)acrylic acid, hydroxyalkyl esters, aminoalkyl esters, hydrophobic monomers such as acronitrile, styrene, chlorostyrene, vinyl acetate, etc. Even if it is a polymer, it can be added at will as long as the polymer obtained by polymerization is water-soluble.

The concentration of the monomer aqueous solution subjected to polymerization is 20 to 45 wt,
% is preferred.As the monomer concentration increases, three-dimensional network reaction is more likely to occur as a by-product, and polymers that are completely water-soluble generally have a lower degree of polymerization. However, by making full use of the techniques described in this application and performing combinations, the most preferable monomer concentration is It is most preferable to maintain the content at 30 to 40 wt.% in order to maintain high quality of coalescence and to obtain the obtained polymer in powder form from an aqueous solution.

In the present invention, by adding a surfactant, a decrease in water solubility due to a crosslinking reaction of the obtained polymer, that is, the formation of a water-insoluble polymer, is prevented, and a polymer having a high molecular weight and good water solubility is obtained. Polymers can be obtained. In addition, polyethylene glycol alkyl phenyl ether (especially, Nonionic surfactants of polyethylene glycol distyrenated phenyl ether) polyethylene glycol alkyl ether, polyethylene glycol fatty acid ester, polyethylene glycol sorbitan fatty acid ester, etc., higher alcohol sulfate ester (salt), alkylaryl sulfone # (salt), alkyl Naphthalene sulfonic acid formalin condensate (salt), dialkyl sulfosuccinate ester (salt)
and 7-ion surfactants such as polyoxyalkylene alkyl ether sulfate (salt).

The blending amount of surfactant is 0.001-1wt% (based on monomer).If it is less than 0.001%, the desired purpose will not be achieved, and if it exceeds 1wt%, the surfactant Because of the effect of chain transfer, the molecular weight of the obtained polymer is extremely low, making it impossible to obtain a high molecular weight polymer as the object of the present invention. E surfactant and one or 2N of primary hypophosphite, urea compound, and aliphatic tertiary amine
This can be used in combination.

Hypophosphites include sodium hypophosphite, potassium hypophosphite, ammonium hypophosphite salts, and amine salts of hypophosphite produced from hypophosphorous acid and tertiary amines. Good too.

Aliphatic tertiary amines include trimethylamine, triethylamine, dimethylethylamine, methyldiethylamine, triethanolamine, methylgetanolamine, dimethylethanolamine, ethylgetanolamine, etc. Urea compounds include urea, thiourea, and ethylene. Urea, ethylene thiourea, guanidine salt e
There is tc.

By blending hypophosphites, aliphatic tertiary amines, and urea compounds, similar to surfactants, the water solubility of the obtained polymer can be improved, that is, the crosslinking reaction in the polymerization reaction can be prevented, and the obtained polymer can be improved. It is possible to prevent cross-linking reactions in intermolecular and intramolecular bonds during the step of crushing and drying the resulting polymer gel.

Although good results can be obtained by adding a surfactant alone,
By using hypophosphites, aliphatic tertiary amines, or urea compounds in combination, even more excellent effects can be achieved.

Next, regarding the blending amount, primary phosphite is 0.001 to 5.0% based on the total amount of monomers. Owt.% is more preferable, and the amount of aliphatic tertiary amine and urea compound is also 0.001 to 5.0% based on the total amount of monomers. Owt
, % is a more preferable range.

The combination of surfactant and hypophosphite, aliphatic tertiary amine, or urea compound can be selected arbitrarily. During the polymerization stage, the amount of dissolved oxygen in the aqueous monomer solution and the amount of gas phase oxygen in the polymerization atmosphere have extremely important effects on the polymerization reaction, so there is a method for removing oxygen that must be suppressed as soon as possible. For example, a known method such as introducing an inert gas such as nitrogen gas, carbon dioxide gas, etc. into the monomer aqueous solution or sealing it in the polymerization gas phase chamber can be adopted.

The dissolved oxygen concentration in the monomer aqueous solution must be limited to 1 mg/I or less before the polymerization reaction; if it exceeds it, unfavorable results such as the generation of unpolymerized portions and failure to improve the degree of polymerization will occur. , The amount of oxygen in the gas phase is also the same as the above reason, and 1 vol. % or less.

The wavelength of the ultraviolet light used for polymerization is most preferably a xenon lamp, tungsten lamp, halogen lamp, carbon arc lamp, as well as a high-pressure mercury lamp or a low-pressure mercury lamp. is 30
0ml to 450mg.

The photopolymerization initiator may be any one commonly used, such as benzophenone, pentyne, benzoin alkyl ether, azo compound, or dye, but benzoin alkyl ether is preferred from the viewpoint of the rate of synthesis.

The photopolymerization initiator is used by adding 0.03 wt, % or less/monomer to an aqueous monomer solution and mixing uniformly. 0.0
Although it is possible to use an amount greater than 3 wt.%, the high molecular weight mold polymer targeted by the present application cannot be obtained.

The polymerization method can be either a patch method or a continuous method, but in the sense of improving production efficiency, it is preferable to perform polymerization continuously on a movable plate, or in a 0-drop granular or block method. Although it can be produced in the form of a thin layer, that is, with a film thickness of 3 to 10 mm, it is more preferable to supply and polymerize the film.

Preferably, the polymerization mode in the production method of the present invention can be efficiently polymerized by cooling with water or cold water in order to completely remove the reaction heat.

In general, the higher the light intensity, the faster the polymerization reaction, but the lower the molecular weight of the resulting polymer.Also, the light irradiation time during polymerization is closely related to the ultraviolet light intensity, so it is important to It is necessary to adjust the ultraviolet light intensity and irradiation time as appropriate depending on the degree of polymerization of the desired polymer.

Therefore, in order to obtain the high molecular weight polymer of the present application, the intensity of ultraviolet rays and the irradiation time must be carefully considered and set.

The intensity of ultraviolet rays on the surface of the polymerization container is set to 50 W/m2 or less, preferably 15 to 30 W/m2. The irradiation time at this time is 25 to 90 minutes, preferably 30 to 60 minutes.

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

The obtained polymer is substantially a highly sticky polymer, but in this application, a surfactant is used to prevent stickiness, so taking it out from the polymerization container is easy.
It can be peeled off and taken out very easily. Particularly when polymerization is carried out using a movable belt, continuous peeling and extraction becomes possible.

In the present application, by coating the movable belt with the tetrafluoroethylene-ethylene copolymer, the generated polymer can be extremely easily peeled off and taken out from the movable belt.

In addition, by coating the movable belt with tetrafluoroethylene-ethylene copolymer and further depositing metal on the back side,
Ultraviolet rays can be irradiated more efficiently and the polymerization reaction can be promoted.

When acrylamide or a monomer solution mainly composed of acrylamide is polymerized at the concentration described above, a hard or highly elastic gel-like material with no fluidity is obtained. Therefore, for example, if you try to volatilize the water contained in a mass or sheet of gel polymer without mechanically crushing it, you will have to leave it under high temperature for a very long time. As a result, the molecular weight of the high-molecular weight i-polymer that has been painstakingly obtained decreases, and crosslinking of the polymer due to thermal changes is promoted, resulting in a significant decrease in commercial value. Therefore, in general, a method is adopted in which the obtained polymer gel mass or sheet-like material is coarsely crushed into small agglomerated particles by some mechanical means, and then dried by heating to remove water. has been done.

Generally, a method is widely adopted in which a polymer gel obtained by polymerization is formed into a strand shape using an extrusion molding machine such as a meat grinder, and then heated and dried. However, it's like a meat grinder.

When using an extrusion molding machine, especially if the polymer gel is extremely hard, the friction on the machine wall will be large, which will not only cause a loss of machine efficiency, but also cause the polymer gel itself to deteriorate due to frictional heat and physical forces. This is not a very preferable method because it results in a decrease in molecular weight due to molecular cleavage.

The present invention also provides a manufacturing method for obtaining a fine-grained polymer gel without deteriorating the polymer gel itself due to frictional heat, physical force, etc., and without causing a decrease in molecular weight due to molecular cutting, etc. It is something.

The form of the polymer gel can be determined, for example, by crushing as described in the patent application filed on November 6, 1980 [title of invention "Method for crushing water-soluble polymer gel" hereinafter referred to as (A) application specification]. It is fed to the crusher from above the machine. The supplied polymer gel is cut into strip-shaped strands by a pair of roller-type cutters rotating in gamma-interlocking directions.

In addition, in order to supply the song combination gel to the roller type cutter,
If the polymer gel is continuously removed from the other end of a movable support, such as an endless belt, and then inserted into a roller-type cutter, the process can be made continuous and production efficiency can be increased. can be improved. A polymer strand cut, for example, into strips by a pair of roller-type cutters rotating in an interlocking direction, is cut by a rotating blade and a fixed blade provided on the outer periphery of the rotating body, and is then cut into strips, preferably into strips. Average particle size 3-1
Cut into 0 mm square strips.

The polymer concentration at this time is maintained at 20-60 wt.%. If it 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 mechanical load will be large, making it difficult to crush it continuously. It becomes impossible. Also,
It is necessary to maintain it within this range in order to maintain water solubility and furthermore to prevent the molecular weight from becoming too low.

The thus obtained 3-10 mm square polymer gel was
A vertical cutting machine, for example, a patent application filed on November 6, 1980 [title of the invention "Method for refining water-soluble polymer gel" hereinafter referred to as (B) Application Specification] Ta? Depending on the C setting, the polymer concentration will be 20-80wt%! Refine the particles to a diameter of 0.3 to 3 mm while maintaining the temperature.

The structure of the cutting machine is characterized by adjusting the gap between the vertical fixed blade and the rotary blade installed vertically inside the cutting machine;
By changing the hole diameter of the sieve and by arranging multiple vertical cutting machines in series, in other words, the cutting machines can be
By passing the gel through several times, it becomes possible to control the residence time of the grinding, and it becomes easy to cut the polymer gel into small particle diameters, for example, 1 mmφ or less. Another point is that the shape of the polymer gel having a small particle size, such as 1 mmφ or less, has a favorable effect of approaching a sphere. The technology for refining crushed polymer gel using a vertical cutter having such a structure has not been established in the past.For example, as a first step,
By cutting using a cutting machine equipped with a mmφ screen, it is possible to obtain a finely divided polymer gel having a uniform particle diameter of about 3 mmφ or less. Then, as a second step, 2mmφ
The particles are finely divided by a cutting machine equipped with a screen of
As a step, when the particles are macerated using a cutting machine equipped with an innφ screen, fine particles with a uniform diameter of about 1 mmφ or less and roundness are obtained. By selecting a screen suitable for the target particle size in this manner, the target particle size can be obtained.

In addition, when the method of the present invention is adopted, 1. In the step of refining the polymer gel, which is essentially in a wet state, by maintaining the polymer concentration at 30 to 60 wt.%, almost no dust is generated. It is possible to obtain particles with a uniform particle size, so to speak, a particle size distribution close to medium dispersion. Therefore, the normally employed process, that is, the step of drying the polymer gel, then pulverizing it 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,
By employing this method, a high molecular weight acrylic polymer with good water solubility and sized particles can be obtained for the first time.

To increase cutting efficiency when crushing polymer gel into fine particles, and to prevent re-adhesion of the obtained fragmented polymer gel and roughly finely divided polymer gel. In addition, 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, when crushing it into small pieces, cooling it sufficiently during the polymerization stage, and cooling the polymer gel obtained by polymerization by blowing cold air etc. before crushing it in a crusher. This can be achieved by forced cooling, usually 10-30°C, preferably 2°C.
It is preferable to adjust the temperature to 0°C or lower.

In addition, in the crushing and pulverization process, if necessary, polyethylene glycol, nonionic surfactant, anionic surfactant, etc. may be added to the crusher or vertical cutting machine.
It may be applied to the surface of the polymer gel or the surface of the crushed polymer gel to prevent re-adhesion of the fragmented polymer gel or finely granulated polymer gel.

The finely granulated polymer gel is usually dried by a known method, for example, using hot air or a ventilation belt, to obtain a granular material having a water content of 10 wt.% or less.

As mentioned above, in the manufacturing method of the present application, it is not necessary to further crush or size the powder or granules, but it is also possible to adopt a crushing and granulation process if necessary. .

The resulting polymer molecular straw has a very high intrinsic viscosity;
For example, the intrinsic viscosity [η] is 20 or more, preferably 25 or more.
It is a polymer of No. 30, has good water solubility, and is sized into liquid particles. A high molecular weight acrylic polymer is obtained.

Next, the invention will be specifically explained with reference to Examples.

Example 1 Prepare the following monomer aqueous solution.

(as pure fractionation xioo%) Acrylamide 160g Acrylic acid Fighting/fighting φ... 30g Caustic soda...Fist...φ... 17g Polyoxyethylene glycol nonylphenyl ether (HLB: 15)... Weigh ・Φφ・−0.06g Sodium hypophosphite・・IIφ・・・・0.01g Thiourea・・e・・ee・Fist・−2g, total y45
Add deionized water so that o o g0 then
Collect 0.4 g of benzoin ethyl ether and dissolve it in dioxane to make a total volume of 10 ml. The above monomer aqueous solution was placed in a demerization tank (cylindrical type with a capacity of 11), nitrogen gas was introduced, and the amount of dissolved oxygen in the monomer aqueous solution was reduced to 0.5.
Then, 1 ml of the above dioxane solution of benzoin ethyl ether is added to the degassed aqueous monomer solution. After that, it is sealed with nitrogen gas, and the amount of oxygen in the gas phase is reduced to 1 vol. Jacketed polymerization equipment (200 m long) installed in a small box-shaped room with
A monomer aqueous solution containing benzoin ethyl ether is supplied in a thin layer within a space (width: 300 mm, height: 50 mm). The thickness of the thin layer at this time was 8.3 mm. 100 located inside the box and above the polymerization container.
The surface of the polymerization vessel was irradiated with W low-pressure mercury lamps (3 units) from a height set so that the ultraviolet rays had an intensity of 20 W/m 2 . At this time, water at 25°C continues to be passed through the jacket. Polymerization started after about 30 seconds. Subsequently, polymerization was continued, and after 30 minutes, ultraviolet irradiation was stopped. The obtained polymer quickly became a hard gel and was easily peeled off from the polymerization container. (A) The obtained polymer gel is crushed using a crusher as described in the application specification. Polymer gel is 3x8x3mm
The vl was cut into angular shapes, and it became a angular gel without adhering to any surface. This angular gel was pulverized using a vertical cutter as exemplified in the application specification (B).

In the first step, a 3 mmφ screen was set for cutting, in the second step, a 2 mmφ screen was set, and in the third step, the particles were finely divided using a vertical cutter equipped with a 1 mmφ screen.

As a result, a polymer gel sized to about 1 mmφ was obtained.

The above crusher and vertical type! The polymer concentrations in the polymer gel at the time of cutting with /I cutting machine were 43 wt, %, and 43 wt, respectively.
It was 45wt,%.

The obtained polymer gel sized to approximately Imnφ was heated at 80°C.
When dried with hot air, the moisture content becomes 10wt in about 25 minutes.
% or less particle size (approximately 0.8 mmφ) was obtained.

This granular material had an intrinsic viscosity of 23 cll/g, became an aqueous solution containing no water-insoluble substances, and was useful as a flocculant.

Example 2 Stainless steel m! V width 450mm, effective length 3,000m
A movable polymerization held is equipped with a tetrafluoroethylene-ethylene copolymer film whose back side is made of aluminum and has a structure that allows hot to cold water to be sprayed onto the endless belt from below. As a formula support, it is completely filled with nitrogen gas and the amount of oxygen in the gas phase is 1v.
ol. The belt was installed in a room with a temperature of less than 10% F, operated at a constant speed of 100 mm/min, and water at 15° C. was sprayed from below the belt. In addition, a low-pressure mercury lamp was installed as an ultraviolet irradiation source in the northern part of the movable support, and the intensity of ultraviolet rays was increased to 30 W/m.
It was set as 2.

Next, acrylamide 12.80kg, acrylic acid 2.40kg, Y-based soda 1.36kg, nonionic surfactant 4.80kg (polyoxyethylene nonylphenyl ether HLB: 15), sodium hypophosphite 0.8g thiourea
Weighed 160g and the debt was 40
A monomer aqueous solution was prepared by adding ionized water so that the amount of monomer was 1.0 kg.

Approximately 40 liters of this aqueous monomer solution was sufficiently degassed with nitrogen gas to reduce the amount of dissolved oxygen to 1 mg/l or less, and was metered onto the belt in operation at a rate of 13.51/hour from one end of the belt.

In addition, a temporary storage tank with an agitator (5
A 5% methanol solution of benzoin isopropyl ether as a polymerization initiator was supplied from 1 volume 31) into the above monomer aqueous solution at a rate of 30 ml/hour, and the monomer aqueous solution and photopolymerization initiator were uniformly mixed while being irradiated with ultraviolet rays. Polymerization was carried out.

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 mm.

Thirty minutes after the start of supplying the monomer aqueous solution, a sheet-like polymer having a thickness of 5 mm was obtained from the other end of the endless belt. The obtained polymer 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. The temperature of the resulting polymer gel was 20°C. The polymer gel sheet continuously obtained from the other end of the endless belt is fed to (A) the crusher exemplified in the application specification, and the 3×5
A square polymer gel of 5 mm in diameter was obtained.

Next, while blowing cold air at about 15°C, the particles were finely divided using a vertical cutting machine as shown in the application specification (B) in which a screen of about 3 mmφ was set, and then a screen of about 2 mmφ and a screen of about 1 mmφ were set. The polymer gel was cut into fine particles having a size of about 1 mm in diameter by passing it through a cutter made in this order.

The resulting finely granulated polymer gel having a diameter of about 1 mm was dried at 80°C in a ventilation band dryer.
It took about 30 minutes to change the powder to a moisture content of 10% or less.

The obtained powder is sized to approximately 0.8 mmφ,
The aqueous solution does not contain any water-insoluble substances and has an intrinsic viscosity of 22
．． It was 5dl/g.

Claims (12)

[Claims] (1) In a method for producing a water-soluble polymer by polymerizing an aqueous solution of acrylamide monomer or other water-soluble vinyl monomers, a) the total amount of monomers in the monomer aqueous solution is 20 to 45 wt%, b) nonionic surfactant, anionic surfactant 1
The species or two or more species are added to the monomer aqueous solution at 0.001 to 1 wt% (based on the monomer), and c) the dissolved oxygen in the monomer aqueous solution is adjusted to 1 mg/l. and then d) 0.03 wt% of the photopolymerization initiator in the monomer aqueous solution.
Below/monomer. e) Then, on a movable belt in an atmosphere where oxygen in the gas phase is 1 vol% or less, the monomer aqueous solution prepared in a) to d) above is placed in a thickness of 3 to 10 mm. f) such aqueous monomer solution on the movable belt, 30
0~450mμ, UV rays below 50W/m^2 from 25~
irradiating for 90 minutes, g) then continuously removing from the movable belt a rubbery layered polymer sheet with a thickness of 3 to 10 mm, and h) irradiating such a rubbery layered polymer sheet with a polymer concentration of 20 to 60 wt%. i) Then, while maintaining the polymer concentration to be 20 to 60 wt%, crush it into square pieces of 3 to 10 mm with a roller cutter, and then crush it to 0.3 to 10 mm squares with a vertical cutting machine while maintaining the polymer concentration to be 20 to 60 wt%. A method for producing a high molecular weight acrylic polymer with good water solubility and sized particles, which comprises: refining the particles to a diameter of 3 mm; and j) drying with hot air. (2) The other water-soluble vinyl monomer is one or more selected from acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid, or vinylsulfonic acid. The manufacturing method described in Scope 1. (3) The nonionic surfactant is polyethylene glycol alkyl phenyl ether (especially polyethylene glycol distyrenated phenyl ether), polyethylene glycol alkyl ether, polyethylene glycol fatty acid ester, polyethylene glycol sorbitan ester, or anionic surfactant. One type selected from higher alcohol sulfate ester (salt), alkylaryl sulfonic acid (salt), alkylnaphthalene sulfonic acid formalin condensate (salt), dialkyl sulfosuccinate ester (salt), and polyoxyalkylene alkyl ether sulfate (salt) or 2 or more types of the manufacturing method according to claim 1. (4) The manufacturing method according to claim 1, in which one or more of hypophosphite, aliphatic tertiary amine, and urea compound are used in combination. (5) The method according to claim 1, wherein the photopolymerization initiator is one or more selected from benzoyl, benzoin alkyl ether, benzyl, benzophenone, and anthraquinone. (6) The manufacturing method according to claim 1, wherein the movable belt is coated with a tetrafluoroethylene-ethylene copolymer, and further, the back surface is metal-deposited. (7) The manufacturing method according to claim 1, wherein the irradiation intensity is 15 to 30 W/m^2 and the irradiation time is 30 to 60 minutes. (8) 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 irradiation. (9) The rubber-like layer polymer 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 sheet surface. Manufacturing method. (10) The manufacturing method according to claim 1, wherein the surface of the rubber laminated polymer sheet is coated with a nonionic surfactant, polyethylene glycol, or an aqueous solution thereof. (11) The manufacturing method according to claim 1, wherein cold air is blown into the vertical cutting machine. (12), the intrinsic viscosity of the high molecular weight acrylic polymer [
η] is 20 or more, the manufacturing method according to claim 1.