JPH07330812A - Production of high-molecular weight acrylamide-based polymer - Google Patents

Abstract

PURPOSE:To remarkably shorten the completion time of polymerization and obtain a polymer containing an extremely small amount of the unreacted residual monomer without deteriorating the solubility and molecular weight by (co)polymerizing (meth)acrylamide or further with other copolymerizable monomers in the presence of an oxidoreduction-based polymerization initiator comprising specific two kinds of oxidizing agents and a reducing agent. CONSTITUTION:This method for producing a high-molecular weight acrylamide-based polymer is to use a polymerization initiator comprising two or more oxidizing agents selected from persulfates, hydrogen peroxide, metallic peroxides, hydroperoxides, dialkyl peroxides, diacyl peroxides, ketone peroxides, dialkyl peroxydicarbonates, peracids and peracid esters as an oxidizing agent and a reducing agent in (co)polymerizing (meth)acrylamide or further with one or more unsaturated monomers copolymerizable therewith in the presence of the oxidoreduction-based polymerization initiator. The reducing agent is selected from salts of transition metallic ions of a low valence, sulfur oxides of a low valence, organic amines and reducing sugars. The amount of the polymerization initiator is 1X10<-4> to 0.5mol% based on the monomers and the molar amount of the reducing agent is 0.01-10 times based on 1 mol oxidizing agent. An azo-based polymerization initiator is further added to initiate the polymerization at. 10-40 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high molecular weight acrylamide polymer mainly used as a polymer flocculant and an additive for papermaking. More specifically, the present invention relates to a method for producing a high molecular weight acrylamide polymer by initiating polymerization with a redox polymerization initiator composed of two or more oxidizing agents.

[0002]

2. Description of the Related Art When an acrylamide polymer is used as a flocculant, the higher the molecular weight within a range that does not hinder handling, the more excellent the flocculation effect is and the more the amount used can be reduced. . Further, in the field of paper strength agents, in recent years, high molecular weight ones have been required.

Conventionally, as a method for producing a high molecular weight acrylamide polymer, a method has been generally used in which the polymerization temperature and the concentration of the polymerization initiator are made as low as possible. However, as the molecular weight becomes higher, the polymerization liquid becomes a gel with the start of the polymerization, and the stirring becomes impossible immediately,
Temperature control becomes impossible. Therefore, in order to keep the polymerization temperature low, it is necessary to lower the polymerization initiation temperature and also lower the polymerization concentration in order to suppress the amount of heat generated by the polymerization.

That is, in the conventional method, in the production of a high molecular weight acrylamide polymer, the concentration of the polymerization initiator, the polymerization initiation temperature and the polymerization concentration must all be lowered, and the time until the polymerization is completed becomes long, As a result, productivity is reduced. On the other hand, if the concentration of the polymerization initiator is simply increased to increase the polymerization rate, the molecular weight will decrease. As described above, a method for cutting off the above correlation and producing a high-molecular-weight acrylamide polymer with high productivity has not been found yet.

Further, in the method for producing a low molecular weight acrylate polymer such as sodium acrylate disclosed in JP-A-4-268304, the combined use of a peroxide type polymerization initiator and a persulfate is disclosed in Examples. However, there is no description about the effect. Furthermore, the method for producing a maleic acid copolymer described in JP-A-3-124711 and JP-A-3-12447.
In the method for producing a fumaric acid copolymer described in JP-A No. 12, it is suggested that a peroxide-based polymerization initiator and a persulfate may be used in combination, but neither specific examples are disclosed nor the effect is described. In any case, the above-mentioned prior art relates to production of a low molecular weight polymer, which is different from the present invention for producing a high molecular weight acrylamide polymer.

[0006]

The production of the high molecular weight acrylamide polymer has the above-mentioned production restrictions, and as a result, there are the following problems to be solved. That is, since it takes a lot of time to complete the polymerization,
Not only are there restrictions on the manufacturing facilities and equipment, but productivity is low, manufacturing costs are high, and the concentration of the polymerization initiator is low, so the reproducibility of the polymerization is low, and the time to complete the polymerization is low. This means that the polymerization is not completed and the unreacted monomer remains because the polymerization initiator concentration and the polymerization concentration are not constant.

[0007]

SUMMARY OF THE INVENTION In view of the above points, the present inventors have studied in detail the method for producing a high molecular weight acrylamide polymer, and as a result, have started polymerization with a redox polymerization initiator to start acrylamide polymerization. In the method for producing a polymer, it was found that a high molecular weight acrylamide polymer can be produced by initiating polymerization in the presence of two or more oxidizing agents, and the present invention has been completed.

That is, according to the present invention, in a method for producing an acrylamide polymer by initiating polymerization with a redox polymerization initiator, the polymerization is initiated with a redox polymerization initiator composed of two or more kinds of oxidizing agents. The present invention relates to a method for producing a high molecular weight acrylamide polymer characterized by the following.

As a method for producing a high molecular weight acrylamide polymer, it is effective to polymerize in a relatively low temperature range, and polymerization with a redox polymerization initiator is generally performed. However, the present invention is a method for producing a high-molecular-weight acrylamide polymer by polymerization with a redox-type polymerization initiator, and by using two or more kinds of oxidant components in combination, almost no decrease in molecular weight is induced and the polymerization rate is Is characterized in that it can be significantly improved. Further, according to the present invention, the production of a high-molecular-weight acrylamide polymer, which has been difficult to produce in the past, can be performed with good reproducibility and efficiency, and restrictions on production equipment can be reduced.

The acrylamide polymer (polyacrylamide) used in the present invention is a homopolymer of acrylamide (or methacrylamide) or one or more unsaturated monomers copolymerizable with acrylamide (or methacrylamide). And a copolymer with.

Examples of the copolymerizable monomer include a hydrophilic monomer, an ionic monomer, a lipophilic monomer and the like, and one or more kinds of these monomers can be applied. Specifically, as the hydrophilic monomer, for example, diacetone acrylamide,
N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N-ethylmethacrylamide, N-ethylacrylamide, N, N-diethylacrylamide, N-propylacrylamide, N-acryloylpyrrolidine, N-acryloylpiperidine, N- Examples thereof include acryloylmorpholine, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, various methoxypolyethylene glycol (meth) acrylates, N-vinyl-2-pyrrolidone and the like.

Examples of the ionic monomer include acrylic acid, methacrylic acid, vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 2-
Acids such as acrylamido-2-methylpropanesulfonic acid and salts thereof such as sodium, potassium, lithium, calcium and magnesium, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylamino Examples thereof include amines such as ethyl acrylate, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylaminopropyl acrylamide, and their tertiary or quaternary salts. Dibasic acids such as maleic acid and fumaric acid may inhibit polymerization and are not preferred.

Examples of the lipophilic monomer include N, N-di-n-propylacrylamide, Nn-butylacrylamide, Nn-hexylacrylamide and Nn-
Hexyl methacrylamide, Nn-octyl acrylamide, Nn-octyl methacrylamide, Nt-
N-alkyl (meth) acrylamide derivatives such as octyl acrylamide, N-dodecyl acrylamide, N-n-dodecyl methacrylamide, N, N-diglycidyl acrylamide, N, N-diglycidyl methacrylamide, N- (4-glycid N- (ω-glycid such as xybutyl) acrylamide, N- (4-glycidoxybutyl) methacrylamide, N- (5-glycidoxypentyl) acrylamide, N- (6-glycidoxyhexyl) acrylamide Xyalkyl) (meth) acrylamide derivative, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
(Meth) acrylate derivatives such as lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate and glycidyl (meth) acrylate, olefins such as acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, ethylene, propylene and butene. Examples thereof include styrene, divinylbenzene, α-methylstyrene, butadiene, isoprene and the like.

The amount of the unsaturated monomer used for the copolymerization varies depending on the type of the unsaturated monomer and the combination thereof, and cannot be said to be unequivocal, but it is generally 0 to 7 for the hydrophilic monomer.
It is in the range of 5% by weight, the ionic monomer is generally 0 to 85% by weight, and the lipophilic monomer is generally 0 to 50% by weight.

A process for polymerizing the above-mentioned monomers to produce a high molecular weight acrylamide polymer will be described. Polymerization is carried out by radical polymerization, and polymerization with a redox polymerization initiator is essential. The redox-based polymerization initiator comprises a combination of an oxidizing agent and a reducing agent. Inorganic oxidants such as persulfates, hydrogen peroxide, metal peroxides and the like as oxidants and hydroperoxides, dialkyl peroxides, diacyl peroxides, ketone peroxides, dialkyl peroxydicarbonates,
There are organic oxides such as peracids and their esters. Furthermore, not only low molecular compounds as organic oxides,
Polymeric oxides can also be used.

Examples of persulfates of inorganic oxidants include ammonium persulfate, potassium persulfate, sodium persulfate and the like. As hydrogen peroxide, a commercially available aqueous solution product can be used. Examples of the metal peroxide include sodium peroxide, potassium peroxide, lithium peroxide, barium peroxide, nickel peroxide, zinc peroxide and the like.

Hydroperoxides of organic oxides include, for example, t-butyl hydroperoxide, cumene hydroperoxide, 1-phenyl-2-methylpropyl-
1-hydroperoxide, tetralin hydroperoxide, diisopropyl peroxycarbonate and the like can be mentioned. Examples of the dialkyl peroxide include di-t-butyl peroxide,
Dicumyl peroxide, 2,5-dimethyl-2,5-di (t-
Butylperoxy) hexane and the like. Examples of the diacyl peroxide include diacetyl peroxide, dipropionyl peroxide, dibutyryl peroxide, dioctanoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, dibenzoyl peroxide, di-2,4-dichlorobenzoyl peroxide and the like. . Examples of the ketone peroxide include methyl ethyl ketone peroxide, cyclohexanone peroxide and the like. Examples of the dialkyl peroxy dicarbonate include dipropyl peroxy dicarbonate, di-2-ethylhexyl peroxy dicarbonate and di-2-ethoxyethyl peroxy dicarbonate. Examples of peracids and esters thereof include peracetic acid, perpivalic acid, perbenzoic acid, t-butyl peracetate, t-butyl perbutyrate, and t-butyl perpivalate.
Butyl, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, perbenzoic acid t
-Butyl and the like.

The polymer peroxide is a polymer having the above-mentioned structure and having a plurality of active oxygen groups in the molecule, and the above-mentioned peroxide can be obtained by appropriately setting the raw materials, synthesis conditions and the like. It can be manufactured by a manufacturing method of a product. For example, JP-A-2-40361 and JP-A-2-40362 disclose diacyl-type polymeric peroxides, and JP-A-5-170808 discloses polymeric peroxydicarbonates.

On the other hand, examples of the reducing agent used in combination with the above-mentioned oxidizing agent include salts of low-valent transition metal ions, low-valent sulfur oxides, organic amines and reducing sugars. As a salt of a low valence transition metal ion, iron (2
Valent), copper (monovalent), cobalt (2,3 valent), manganese (2 valent) and the like, and specifically, sulfuric acid first
Examples include ammonium iron, cuprous chloride, and cobalt chloride (divalent). Examples of low-valent sulfur oxides include sulfites, bisulfites, pyrosulfites, sulfoxylates and the like, and their alkali metal salts such as Na ⁺ and K ⁺ and ammonium salts are generally soluble. Used more. As the organic amine, both an aliphatic amine and an aromatic amine can be used. As the aliphatic amine, those having low volatility are preferable. For example, ethylenediamine, N, N-dimethylaminopropylamine, N, N, N ′, N ′. -Tetramethylethylenediamine and the like. Examples of aromatic amines include aniline, N, N-dimethylaniline, benzylamine, N, N-dimethylbenzylamine and the like. Examples of reducing sugars and similar substances include monosaccharides such as aldose and ketose, disaccharides such as saccharose, maltose and lactose, and similar substances such as ascorbic acid.

In the polymerization of acrylamide-based monomers, the polymerization system gels, and as a result, it becomes difficult to remove the heat of polymerization. Therefore, it is usually left as it is after the initiation of the polymerization. Therefore, the polymerization proceeds adiabatically, and the temperature of the polymerization system rises and rises from around 0 ° C to around 100 ° C. In order to make the polymerization proceed rapidly in such a wide temperature range, the above-mentioned polymerization initiators are properly combined,
Polymerization is preferably performed or a new initiator is preferably used in combination. There are various polymerization initiators as the third component used in combination with such a redox polymerization initiator, and for example, an azo initiator can be used. Among them, those effective in initiating polymerization in a temperature range higher than the medium temperature range are preferable. For example, azobis (2-amidinopropane) dihydrochloride, azobis (2-methylbutyronitrile), azobisisobutyronitrile, azobis (4-cyanovaleric acid), dimethyl azobisisobutyrate, azobis [2- (2- (2- Imidazoline-2
-Yl) propane] dihydrochloride, azobisisobutyramide, azobis [2- (hydroxymethyl) propionitrile] and the like.

In the present invention, the acrylamide monomer is polymerized using the above-mentioned polymerization initiator, and water is most preferable as the polymerization solvent. As water, industrial water can be used as it is, but ion-exchanged water, distilled water, and well water containing few impurities such as metal ions are preferable. In addition, lower alcohols such as methanol and ethanol, acetone, tetrahydrofuran, dioxane,
A polar solvent miscible with water, such as dimethylformamide or N-methylpyrrolidone, can be used together. These solvents are convenient because they can be used as the solvent when a poorly water soluble polymerization initiator is used.

In the present invention, the above-mentioned polymerization solvent is used for the polymerization, and the monomer concentration at that time is 2 to 70.
% By weight, preferably 5 to 50% by weight. Further, the addition amount of the polymerization initiator is 1 × 10 in terms of the total amount of the oxidizing agent with respect to the monomer.
^{-4 to} 0.5 mol%, preferably 1 × 10 ^{-4 to} 0.1 mol%, and the relative ratio of each component of the oxidizing agent is 1:50 to.
It is in the range of 50: 1, and even if it is too small,
If there is too much, the concerted effect due to the combined use will be diminished. It should be noted that, in many cases, the combined effect of the oxidizing agents to be used in combination is different from that of the same type, in which a superior effect is obtained. For example, persulfate and hydrogen peroxide, persulfate and hydroperoxide, persulfate and dialkyl peroxide, persulfate and diacyl peroxide, persulfate and ketone peroxide, persulfate and dialkyl peroxydicarbonate, Persulfates and peracids, persulfates and peresters, persulfates and polymeric oxides, hydrogen peroxide and hydroperoxides, hydrogen peroxide and dialkyl peroxides, hydrogen peroxide and diacyl peroxides, and peroxides Hydrogen and ketone peroxide, hydrogen peroxide and dialkyl peroxydicarbonate, hydrogen peroxide and peracid, hydrogen peroxide and perester, hydrogen peroxide and polymeric oxides, hydroperoxide and dialkyl peroxide, hydroperoxide Diacyl peroxide, hydroperoxide and ketone peroxide, hydroperoxide and dialkyl peroxydicarbo , Hydroperoxides and peracids, hydroperoxides and peresters, hydroperoxides and polymeric oxides, dialkyl peroxides and diacyl peroxides, dialkyl peroxides and ketone peroxides, dialkyl peroxides and dialkyl peroxydicarbonates, Dialkyl peroxides and peracids, dialkyl peroxides and peroxyesters, dialkyl peroxides and polymeric oxides, diacyl peroxides and ketone peroxides, diacyl peroxides and dialkylperoxydicarbonates, diacyl peroxides and peracids, peroxides Diacyl oxides and peroxyesters, diacyl peroxides and polymeric oxides, ketone peroxides and dialkylperoxydicarbonates, ketone peroxides and peracids, ketone peroxides and peroxyesters, ketone peroxides and polymeric oxides , Dialkyl Oxy dicarbonate and the peracid,
Dialkyl peroxydicarbonate and perester,
It is a combination of dialkyl peroxydicarbonate and polymer oxide, peracid and polymer oxide, and perester ester and polymer oxide. Further, three or more kinds of oxidizing agents can be used together.

On the other hand, the reducing agent can be arbitrarily selected from those described above. In the initiation of polymerization at a low temperature near 0 ° C., the use of a salt of a transition metal ion having a low valence allows rapid initiation of the polymerization. In any case, polymerization can be initiated at 40 ° C. or lower by using the above-mentioned reducing agent. The ratio of the reducing agent to the oxidizing agent used is 0.01 with respect to 1 mol of the oxidizing agent.
It is a 10-fold molar amount, preferably 0.02 to 5-fold molar amount.

The azo-based polymerization initiator, which is the third component polymerization initiator, is not indispensable, but it is convenient to use the azo-based polymerization initiator in combination because the polymerization can be carried out rapidly and with good reproducibility. The addition amount is 1 × 10 ⁻³ to the monomer.
It is 5 mol%, preferably 1 × 10 ⁻³ to 1 mol%. The addition method can be arbitrarily selected such as a method of adding it to the aqueous monomer solution in advance, a method of adding it simultaneously with the addition of the redox polymerization initiator, and the like.

There is no particular restriction on the pH at the start of polymerization,
The pH is generally in the range of 3 to 10. The polymerization initiation temperature is approximately -10 to 40 ° C, although it varies depending on the combination of the oxidizing agent and the reducing agent, their concentrations and ratios. After the initiation of polymerization, the temperature is raised by the heat of polymerization generated as the polymerization proceeds. When the polymerization concentration is low and stirring is possible, the temperature can be controlled and set to a desired temperature, but under normal conditions, the polymerization liquid often gels with the progress of polymerization. Since it is difficult to control the temperature, it is common to leave the temperature as it is. The maximum temperature reached is almost uniquely determined by the polymerization initiation temperature and the polymerization concentration, and the polymerization conditions are usually set to 50 to 110 ° C. Further, the polymerization time is generally 1 to 100 hours, though it varies depending on the kind of the monomer.

At the start of the polymerization, the atmosphere of the polymerization system may contain oxygen like air, but in order to carry out the polymerization rapidly and with good reproducibility, the oxygen is replaced with an inert gas such as nitrogen gas. It is preferable to keep. It is preferable to remove not only the gas in the polymerization container but also oxygen dissolved in the acrylamide monomer aqueous solution and the initiator aqueous solution.

More specifically, an aqueous solution of an acrylamide monomer from which dissolved oxygen has been removed is added to a predeoxygenated polymerization vessel, the polymerization initiation temperature is set, and the predeoxygenated polymerization initiator aqueous solution is stirred. A predetermined amount is added below to start the polymerization. During that time, in order to prevent air from being mixed, it is preferable to introduce an inert gas such as nitrogen gas into the polymerization container.

The temperature rises as the polymerization progresses, but is left to stand until the maximum temperature is reached. After reaching the maximum temperature, if necessary, the acrylamide polymer is obtained by leaving the temperature as it is or by subjecting it to heat treatment such as immersion in hot water. In addition, polymerization can be initiated by mixing with an aqueous solution of a polymerization initiator using, for example, a static mixer while flowing in the acrylamide monomer solution. In this case, since the mixing can be performed under circulation, a stirrer is not necessarily required in the polymerization container. For example, the above-mentioned mixed solution may be sealed in a container such as a drum and allowed to stand for the progress of the polymerization as it is, and then allowed to stand to carry out the polymerization.

Furthermore, an aqueous monomer solution mixed with a polymerization initiator is injected into one end of a portable transportation device such as a belt conveyer, and then the belt is moved in accordance with the progress of polymerization, and the acrylamide polymer is introduced from the other end. Polymerization equipment designed to take out the can also be used. Since the polymer thus obtained has a large molecular weight, the state of the liquid after polymerization is either a paste having a very high viscosity or a gel having a loss of fluidity. In the case of a paste, it is possible to transfer the liquid with a pump, so that the product can be used as it is. On the other hand, in the case of a gel state, it takes a lot of time to dissolve the gel as it is. When it is used as an aqueous solution as described above, it is preferable to dilute it with water and place it in the form of an aqueous solution. Further, in the case of a solid product such as a powder, a method of obtaining a polymer by impregnating an acrylamide polymer such as methanol with an insoluble organic solvent such as methanol and dehydrating the acrylamide polymer, or Shred the polymer gel with a shredder such as a meat grinder,
There is a method of drying it at 50 to 150 ° C. and further pulverizing it to give a powder. As the dryer, a hot air conveyor dryer, a cylinder dryer, an infrared dryer, a high frequency dryer, etc. can be used. Further, when the quality deterioration such as insolubilization due to drying is extremely disliked, a freeze-drying device or the like can be used.

Further, the polymer dried by the above-mentioned method is pulverized into a powdery product, and the pulverization method is preferably a dry method, and the pulverizer is a roll crusher, a dodge crusher, a hammer mill, a rotary crusher, a ball mill, A rod mill, roller mill, pin mill, micronizer, etc. can be used. The acrylamide polymer produced by the above method generally has a weight average molecular weight of 2
It is from 0,000,000 to 20,000,000 and is useful as a polymer flocculant, a petroleum recovery agent, and a papermaking agent (paper strength enhancer, drainage improver, retention improver, etc.)

The acrylamide polymer produced as described above has a very high molecular weight, but naturally it is difficult to use it for various purposes unless it has good solubility in an aqueous solution. Therefore, the key point of product quality is how to reduce the amount of insoluble matter that does not dissolve in water.
Various dissolution test methods have been developed. The simplest method is to add distilled water to a polymer concentration of about 0.1%, dissolve by stirring for a predetermined time, and then filter with a filter cloth or a wire net to measure the insoluble content. Also, a method of adding a water-soluble salt to water to be dissolved and varying the salt concentration to test the solubility can be applied. The molecular weight of the acrylamide polymer can be determined by a column fractionation method such as gel permeation chromatogram or by measuring the intrinsic viscosity, and by the conversion formula of the intrinsic viscosity and the molecular weight.

[0032]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Example 1 [Production of acrylamide polymer]; 650 g of 50% by weight acrylamide aqueous solution and 650 g of distilled water and 2.06% by weight of 2,2-azobis (2-amidinopropane) dihydrochloride (hereinafter abbreviated as V-50). After adding 20 g of the aqueous solution (2.9 × 10 ⁻² mol% to the monomer), 26.9 mg of 1 wt% hydrogen peroxide solution (1.5 × 10 ⁻⁴ to the monomer) was added.
Mol%) and adjusted to pH 7.
It was adjusted to 0 to prepare an acrylamide aqueous solution. Adjust the temperature of the acrylamide aqueous solution to below the polymerization initiation temperature (0 ° C),
After transferring the solution to a 2 L Dewar bottle, a nitrogen introduction tube and a thermometer were attached, and a stopper was fitted with a silicone rubber provided with an exhaust hole and a catalyst addition hole, and dissolved oxygen was removed from the solution by passing 850 ml / min of nitrogen gas for 1 hour.

Next, when the liquid temperature reaches 0 ° C., 9.0 ×
40 g of an aqueous solution of 10 ⁻³ wt% ammonium persulfate (hereinafter abbreviated as APS) (3.0 × 10 ⁻⁴ mol% with respect to the monomer), 7.8 × 10 ⁻³ wt% ferrous ammonium sulfate (hereinafter , FAS) 40 g of an aqueous solution (1.5 × 10 ⁻⁴ mol% with respect to the monomer) is rapidly injected at the same time, the polymerization is started by stirring, and then the nitrogen introducing pipe is pulled up from the liquid surface to a reaction vessel. The upper part was kept in a nitrogen atmosphere and left as it was for adiabatic polymerization. After the polymerization temperature reached the maximum point, it was left as it was for 1 hour. At this time, the maximum temperature and the time to reach the maximum temperature (polymerization time) were measured. The results are shown in Table 1.

The peripheral portion of the acrylamide polymer thus obtained was removed with scissors, shredded, finely crushed with a meat grinder, and then dried with hot air at 85 ° C. for 110 minutes,
Grind for 1 minute with a high-speed rotary blade crusher and sift it 2
Particles of 0 to 60 mesh were classified to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to the following test, and the results are shown in Table 1.
It was shown to. The water content of the dry powdery acrylamide polymer sample was about 10% by weight for all the samples.

[Solubility test of acrylamide polymer]: Put 400 g of distilled water in a 500 ml beaker,
While stirring the screw type stirring blade at 200 rpm, 0.44 g (pure content 0.4 g) of acrylamide polymer was added and dissolved by stirring for 90 minutes, and the obtained solution was filtered through a 150 mesh stainless steel wire net, The insoluble matter was visually judged. The insoluble content was determined according to the following criteria. ◯: No insoluble matter Δ: Small amount of insoluble matter ×: Large amount of insoluble matter [Measurement of molecular weight of acrylamide polymer]: Weight of acrylamide polymer by gel permeation chromatography of the filtrate obtained in the above solubility test The average molecular weight was measured.

Examples 2 to 8 In exactly the same manner as in Example 1 with the indicated amounts of the oxidizing agent added at the time of preparing the polymerization solution shown in Table 1 and the redox polymerization initiator used at the initiation of the polymerization and the polymerization initiation temperature. An acrylamide polymer was produced, the maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1.

Example 9 In the production of the acrylamide polymer of Example 1, 2.
1.26 wt% azobisisobutyronitrile-methanol solution 20 instead of 20 wt% 06 wt% V-50 aqueous solution
An acrylamide polymer was produced in the same manner as in Example 1 except that g was added, and the maximum temperature and polymerization time at that time were measured. The results are shown in Table 1. Then, the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1.

Example 10 In the production of the acrylamide polymer of Example 1, 2.
An acrylamide polymer was produced in the same manner as in Example 1 except that 20 g of water was added instead of 20 g of a 06 wt% V-50 aqueous solution, and the maximum temperature and polymerization time at that time were measured. The results are shown in Table 1. Then, the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated except that the acrylamide polymer of Example 1 was produced without adding hydrogen peroxide. The maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1. In this case, the molecular weight and the solubility were almost the same as in Example 1, but in Example 1, the polymerization time was longer than in the case where the polymerization was completed in a short time.

Comparative Example 2 The same procedure as in Example 1 was carried out except that hydrogen peroxide and V-50 were not added in the production of the acrylamide polymer of Example 1. The maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1. In this case as well, the molecular weight and solubility were almost the same as in Example 1, but the polymerization time was much longer.

Comparative Example 3 In the production of the acrylamide polymer of Example 1, hydrogen peroxide was not added, and the redox type polymerization initiator A was used.
Example 1 except that PS was produced by adding 6.0 × 10 ⁻⁴ mol% to the monomer and FAS to 3.0 × 10 ⁻⁴ mol% to the monomer. I went in the same way. The maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1. In this case, the polymerization time was about the same as in Example 1 due to the increase in the polymerization initiator, but the molecular weight was much lower. Comparative Example 4 The procedure of Example 5 was repeated except that the acrylamide polymer of Example 5 was produced without adding hydrogen peroxide. The maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1. In this case, the molecular weight and solubility were almost the same as in Example 5, but the polymerization time was much longer.

Comparative Example 5 The procedure of Example 7 was repeated except that the acrylamide polymer of Example 7 was produced without adding hydrogen peroxide. The maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 1. In this case, the molecular weight and solubility were almost the same as in Example 7, but the polymerization time was much longer.

[0043]

[Table 1]

Example 11 [Production of acrylamide-based polymer consisting of acrylamide-acrylic acid]: 50% by weight acrylamide aqueous solution 4
50g and acrylic acid 150g, distilled water 800g and 2.0
After adding 20 g of a 5 wt% V-50 aqueous solution, hydrogen peroxide was added to 2.5 × 10 ⁻⁴ mol% of the monomer, and the pH was adjusted to 7.0 with an aqueous sodium hydroxide solution. Then, an acrylamide aqueous solution was prepared. Polymerization start temperature (0
(° C), the temperature of the acrylamide aqueous solution is adjusted to below, and after transfer to a 2 L Dewar bottle, a nitrogen introduction tube and a thermometer are attached, an exhaust port,
The stopper was capped with silicone rubber provided with a catalyst addition hole, and dissolved oxygen was removed from the solution by passing 850 ml / min of nitrogen gas for 1 hour.

Next, when the liquid temperature reaches 0 ° C., 9.0 ×
40 g of 10 ⁻³ wt% APS aqueous solution (3.
^{0x10 -4} mol%) and 7.7x10 ^-3 wt% FAS aqueous solution 40 g (1.5x10 ^-4 mol% with respect to the monomer) were rapidly injected simultaneously and polymerization was started by stirring. After that, the nitrogen introduction tube was pulled up from the liquid surface, the upper part of the reaction vessel was kept in a nitrogen atmosphere, and left as it was for adiabatic polymerization. After the polymerization temperature reached the maximum point, it was left as it was for 1 hour. At this time, the maximum temperature and the polymerization time were measured. The results are shown in Table 2. After that, the same operation as in Example 1 was performed to perform a performance evaluation test. The results are shown in Table 2.

Examples 12 to 18 In the same manner as in Example 11, the indicated amounts of the oxidizing agent added at the time of preparing the polymerization solution and the redox polymerization initiator used at the initiation of the polymerization and the polymerization initiation temperature shown in Table 2 were used. An acrylamide polymer was produced, the maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 2.

Example 19 In the production of the acrylamide polymer of Example 11,
20% water instead of 20 g of 2.05 wt% V-50 aqueous solution
An acrylamide polymer was produced in the same manner as in Example 11 except that g was added, and the maximum temperature and polymerization time at that time were measured. The results are shown in Table 2. Then, the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 2.

Comparative Example 6 In the production of the acrylamide polymer of Example 11,
The same procedure as in Example 11 was carried out except that the production was carried out without adding hydrogen peroxide. The maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 2. In this case, the molecular weight and the solubility were almost the same as in Example 11, but the polymerization time was much longer than that in Example 11 in which the polymerization was completed in a short time.

[0049]

[Table 2]

Example 20 [Polymerization of acrylamide polymer consisting of acrylamido-methacryloyloxytrimethylammonium chloride]: 450 g of 50% by weight acrylamide aqueous solution, 150 g of methacryloyloxytrimethylammonium chloride, 800 g of distilled water and 1.56% by weight of V-50.
After adding 20 g of the aqueous solution, hydrogen peroxide was added to 2.5 × 10 ⁻⁴ mol% with respect to the monomer, and the pH was adjusted to 4.5 with the sulfuric acid aqueous solution to prepare an acrylamide aqueous solution. After adjusting the temperature of the acrylamide aqueous solution to below the polymerization initiation temperature (0 ° C) and transferring it to a 2 L Dewar bottle, attach a nitrogen introduction tube and a thermometer, plug it with a silicone rubber provided with an exhaust hole and a catalyst addition hole, and for 1 hour. Then, dissolved oxygen in the solution was removed by passing 850 ml / min of nitrogen gas.

Then, when the liquid temperature reaches 0 ° C., 6.8 ×
40 g of 10 ⁻³ wt% APS aqueous solution (3.
(0 × 10 ⁻⁴ mol%), 5.8 × 10 ⁻³ wt% FAS aqueous solution 40 g (1.5 × 10 ⁻⁴ mol% with respect to the monomer) were rapidly injected at the same time and the polymerization was started by stirring. After that, the nitrogen introduction tube was pulled up from the liquid surface, the upper part of the reaction vessel was kept in a nitrogen atmosphere, and left as it was for adiabatic polymerization. After the polymerization temperature reached the maximum point, it was left as it was for 1 hour. At this time, the maximum temperature and the polymerization time were measured. The results are shown in Table 3. After that, the same operation as in Example 1 was performed to perform a performance evaluation test. The results are shown in Table 3.

Examples 21 to 23 In the same manner as in Example 20, the indicated amount of the oxidizing agent added at the time of preparing the polymerization solution shown in Table 3 and the redox polymerization initiator used at the initiation of the polymerization and the polymerization initiation temperature were used. An acrylamide polymer was produced, the maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 3.

Example 24 In the production of the acrylamide polymer of Example 20,
20 g of water instead of 20 g of 1.56 wt% V-50 aqueous solution
An acrylamide polymer was produced in the same manner as in Example 20 except that g was added, and the maximum temperature and polymerization time at that time were measured. The results are shown in Table 3. Then, the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 3.

Comparative Example 7 In the production of the acrylamide polymer of Example 20,
The same procedure as in Example 20 was carried out except that the production was carried out without adding hydrogen peroxide. The maximum temperature and polymerization time at that time were measured, and the same operation as in Example 1 was performed to obtain a dry powdery acrylamide polymer sample. The obtained acrylamide polymer sample was subjected to a solubility test and a molecular weight measurement in the same manner as in Example 1 to evaluate the performance. The results are shown in Table 3. In this case, although the molecular weight and the solubility were almost the same as in Example 20, the polymerization time in Example 20 was much longer than that in Example 20.

Comparative Example 8 450 g of 50% by weight acrylamide aqueous solution and 1 of fumaric acid
After adding 800 g of distilled water and 20 g of a 1.74 wt% V-50 aqueous solution to 50 g, hydrogen peroxide was added to the monomer in 2.
5 × 10 ⁻⁴ mol% was added and the pH was adjusted to 4.5 with an aqueous sodium hydroxide solution to prepare an acrylamide aqueous solution. After adjusting the temperature of the acrylamide aqueous solution to below the polymerization initiation temperature (0 ° C) and transferring it to a 2 L Dewar bottle, attach a nitrogen introduction tube and a thermometer, and plug with silicone rubber provided with an exhaust hole and a catalyst addition hole. Time, nitrogen gas 850ml / m
The dissolved oxygen in the solution was removed through in.

Next, when the liquid temperature reaches 0 ° C., 7.6 ×
40 g of 10 ⁻³ wt% APS aqueous solution (3.
0 x 10 ^-4 mol%) and 6.5 x 10 ^-3 wt% FAS aqueous solution (40 g, 1.5 x 10 ^-4 mol% based on the monomer) were rapidly injected simultaneously to initiate polymerization. The reaction temperature did not rise easily, and the reaction temperature was only 4 ° C. for 5 hours, and the reaction solution was slightly viscous and hardly reacted. The same was true when maleic acid was added instead of fumaric acid.

[0057]

[Table 3]

[0058]

In general, the polymerization completion time is shortened with the increase of the polymerization initiator, but the molecular weight of the obtained polymer is decreased with the increase of the polymerization initiator. However, in the polymerization with the redox-based polymerization initiator of the present invention, the polymerization completion time is compared with the case where the redox-based polymerization initiator is used alone by the method of performing the polymerization by using two or more kinds of oxidizing agents in combination. Can be significantly shortened (shortened to about 1/4 to 3/4), and this phenomenon is different from the result estimated by general theory, and the solubility and molecular weight of the obtained polymer are not lowered at all. It can be performed. Further, since the concentration of the polymerization initiator is not extremely low, the amount of unreacted monomer remaining is very small, the reproducibility of the polymerization is good, and the completion time of the polymerization is almost constant. In this way, the residual amount of unreacted monomer can be made extremely small, and the polymerization can be carried out with relatively good reproducibility, and the polymerization completion time can be shortened without deteriorating the performance of the high molecular weight acrylamide polymer. Therefore, it is possible to reduce restrictions in terms of manufacturing facilities and equipment, significantly improve productivity, and reduce manufacturing costs.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanako Oyanagi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd. (72) Kenichi Nakamura 1190 Kasama-cho, Sakae-ku, Yokohama, Kanagawa Mitsui Toatsu Inside Chemical Co., Ltd.

Claims (9)

[Claims] 1. In the presence of a redox polymerization initiator (meth)
A method for producing an acrylamide-based polymer by polymerizing one or more unsaturated monomers copolymerizable with acrylamide or (meth) acrylamide, which comprises a persulfate, hydrogen peroxide, a metal peroxide, or a hydroperoxide. Peroxide, dialkyl peroxide, diacyl peroxide, ketone peroxide,
A high-molecular-weight acrylamide system characterized by carrying out polymerization in the presence of a redox-type polymerization initiator consisting of two or more kinds of oxidizing agents and reducing agents selected from the group consisting of dialkyl peroxydicarbonates, peracids and peracid esters. Method for producing polymer. 2. Two or more oxidizing agents are persulfate and hydrogen peroxide, persulfate and hydroperoxide, persulfate and dialkyl peroxide, persulfate and diacyl peroxide, persulfate and ketone peroxide. , Persulfates and dialkyl peroxydicarbonates, persulfates and peracids, persulfates and peresters, persulfates and polymeric oxides, hydrogen peroxide and hydroperoxides, hydrogen peroxide and dialkyl peroxides, Hydrogen peroxide and diacyl peroxide, hydrogen peroxide and ketone peroxide, hydrogen peroxide and dialkyl peroxydicarbonate, hydrogen peroxide and peracid, hydrogen peroxide and perester, hydrogen peroxide and polymeric oxides, Hydroperoxide and dialkyl peroxide, hydroperoxide and diacyl peroxide,
Hydroperoxides and Ketones Peroxides, Hydroperoxides and Dialkyl Peroxydicarbonates, Hydroperoxides and Peracids, Hydroperoxides and Peresters, Hydroperoxides and Polymeric Oxides, Dialkyl Peroxides and Diacyl Peroxides, Dialkyl Peroxides and Ketones Peroxide, dialkyl peroxide and dialkyl peroxydicarbonate, dialkyl peroxide and peracid, dialkyl peroxide and perester ester, dialkyl peroxide and polymeric oxides, diacyl peroxide and ketone peroxide,
Diacyl peroxide and dialkyl peroxydicarbonate, diacyl peroxide and peracid, diacyl peroxide and peroxyester, diacyl peroxide and polymeric oxides, ketone peroxide and dialkylperoxydicarbonate, ketone peroxide and peracid, Ketone peroxide and peroxyester, ketone peroxide and high-molecular peroxide,
Dialkylperoxydicarbonate and peracid, dialkylperoxydicarbonate and peroxyester, dialkylperoxydicarbonate and polymeric oxide, peracid and polymeric oxide, peracid ester and polymeric oxide The manufacturing method according to claim 1. 3. The method according to claim 1, wherein the reducing agent is a reducing agent selected from the group consisting of salts of low valence transition metal ions, low valence sulfur oxides, organic amines and reducing sugars. 4. The addition amount of the polymerization initiator is in the range of 1 × 10 ^{−4 to} 0.5 mol% with respect to the total amount of the oxidizing agent relative to the monomers,
The production method according to claim 1, wherein the use ratio of the reducing agent to the oxidizing agent is 0.01 to 10 times mol with respect to 1 mol of the oxidizing agent. 5. The production method according to claim 4, wherein an azo polymerization initiator is further added to the monomer in an amount of 1 × 10 ^{−3 to} 5 mol%. 6. The production method according to claim 1, wherein the polymerization is initiated at -10 to 40 ° C., and then the polymerization is performed by spontaneously increasing the temperature. 7. The weight average molecular weight of the polymer is 2,000,000-2.
The manufacturing method according to claim 1, which is 10 million. 8. The obtained polymer is further shredded and dried,
The manufacturing method according to any one of claims 1 to 7, which is pulverized into a powder form. 9. An aggregating agent mainly composed of a powdery high molecular weight acrylamide polymer obtained by the method according to claim 8.