JPH038365B2 - - Google Patents

Description

[Detailed description of the invention]

Water-soluble polymeric substances are widely used as flocculants, thickeners, retention improvers for papermaking, water-based improvers, fluidity regulators for oil recovery, and the like. It is generally known that the higher the polymerization degree of water-soluble polymer substances used for these purposes, the more effective they are, and in order to obtain water-soluble polymer substances with a higher degree of polymerization, aqueous solution polymerization, emulsion polymerization, and suspension polymerization are used. Improvements in polymerization methods such as polymerization, and improvements in polymerization initiation methods such as polymerization initiation using redox initiators, azo initiators, radiation, etc.
Also, research is being conducted into improving the types of raw material monomers and their quality. Currently, polyacrylamide with a polymerization degree of about 200,000 is known as a water-soluble polymer substance with a high polymerization degree, but when the polymerization degree is further increased, the water solubility of the polymer substance generally decreases significantly, and its use defects occur. Therefore, in order to further increase the effectiveness of water-soluble polymer substances for reuse purposes, it has been desired to develop water-soluble polymer substances with a higher degree of polymerization than before. The present inventors have completed the present invention as a result of intensive research into methods for producing such water-soluble polymeric substances. That is, the present invention relates to the general formula OHC-
An aliphatic dialdehyde represented by R-CHO (wherein R represents an alkylene group or an alkenylene group) is added to the acrylamide monomer in an amount of 10 ^-5 to 10 ^-2
This is a method for producing an acrylamide-based water-soluble polymer substance, which is characterized by polymerizing an acrylamide-based monomer in an aqueous medium in the presence of mol% of the acrylamide-based monomer. Although it has a higher degree of polymerization, it shows water solubility. Furthermore, the water-soluble polymeric substance obtained by the method of the present invention has a similar degree of polymerization as that of the water-soluble polymeric substance obtained by the conventional method.
A flocculant used in wastewater treatment, water/sewage treatment, and treatment of suspensions in various production processes; shows remarkable effects as a retention improver and aqueous quality improver in paper manufacturing processes. The raw material acrylamide monomer used in the method of the present invention is acrylamide, methacrylamide,
Alternatively, it is a mixture of acrylamide or methacrylamide and another vinyl monomer copolymerizable with these. Other copolymerizable vinyl monomers include acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid or salts thereof, dimethylaminoethyl methacrylate, N-dimethylaminopropylmethacrylamide, or these acids. Addition salts or quaternized salts, alkyl acrylates, vinylpyrrolidone, vinylpyridine, vinyl acetate, etc. can be used. When the acrylamide monomers are a mixture, the mixing ratio of acrylamide or methacrylamide is 10 mol % or more. According to the method of the invention, polyacrylamide,
Nonionic polymer substances such as polymethacrylamide, acrylamide, methacrylamide, etc. and acrylic acid, methacrylic acid, 2-acrylamide.
Anionic polymeric substances such as copolymers with 2-methylpropanesulfonic acid or salts thereof,
and cationic polymeric substances such as copolymers of acrylamide, methacrylamide, etc. with dimethylaminoethyl methacrylate, N-dimethylaminopropylmethacrylamide, or their acid addition salts or quaternized salts. It is possible to produce water-soluble molecular substances with a high degree of polymerization. Further, the water-soluble polymer substance obtained by polymerization reaction in an aqueous medium according to the method of the present invention can be made into powder by alcohol dehydration, physical dehydration, heat drying, etc., as necessary. As the aliphatic dialdehyde in the present invention, malonaldehyde, succinaldehyde, malealdehyde, fumaraldehyde, glutaraldehyde, adipaldehyde, etc. can be used.
They may be used alone or in combination of two or more of them. The amount of these aliphatic dialdehydes used varies depending on the type and the type and mixing ratio of the acrylamide monomer, but generally 10 ^-5
~10 ⁻² mol % is preferred. When the amount is less than this, the polymerization degree of the obtained polymer material is not much different from that of the polymer material obtained without using aliphatic dialdehyde, and when the amount used is too large, the polymerization degree of the obtained polymer material is becomes difficult to dissolve in water. The acrylamide-based water-soluble polymer substance can be produced by the method of the present invention by adding a polymerization initiator to a mixture of the acrylamide-based monomer and aliphatic dialdehyde in an aqueous medium and polymerizing the mixture. As a polymerization method in an aqueous medium, aqueous solution polymerization, emulsion polymerization, suspension polymerization, etc. can be applied, but aqueous solution polymerization is generally preferable from the viewpoint of stability and economic efficiency than emulsion polymerization or suspension polymerization using an organic solvent. The concentration of the monomer in the aqueous medium during polymerization is not particularly limited, but is preferably from 10 to 80% from the viewpoint of heat generation during polymerization, its temperature control, and economical efficiency when isolating the polymer. The polymerization temperature is not particularly limited as long as it is below the boiling point of the aqueous medium, but 20 to 70°C is suitable. The polymerization initiator is an azo initiator such as 2,2'-azobis(2-amidinopropane) hydrochloride, sodium azobiscyanovalerate, or a peroxide such as hydrogen peroxide, t-butyl hydroperoxide, persulfate, etc. A redox initiator is used in combination with a reducing agent such as sodium sulfite, sodium hydrosulfite, or ferrous sulfate, and an azo initiator and a redox initiator may be used in combination. The reason why the degree of polymerization of the acrylamide-based water-soluble polymer material polymerized by adding an aliphatic dialdehyde by the method of the present invention is higher than that of the conventional material polymerized without adding an aliphatic dialdehyde is that the aliphatic dialdehyde reacts with the amide group in the acrylamide monomer or polymer, producing a type of polymeric substance in which acrylamide polymer molecules are cross-linked, for example as shown in formula (1) or (2) below. (In the formula, R represents an alkylene group or an alkenylene group, and 〓〓〓 represents a polymer chain.)

【formula】

[Formula] In other words, a crosslinking reaction such as an addition reaction, a condensation reaction, or a polycondensation reaction between the amide group of the raw material acrylamide monomer and the aldehyde group of the aliphatic dialdehyde creates a radical of the vinyl group of the acrylamide monomer. It is thought that a partially crosslinked polymeric substance with a high degree of polymerization is produced by proceeding in parallel with the polymerization reaction. When the acrylamide-based water-soluble polymer substance produced by the method of the present invention is used as a flocculant or thickener, it shows a remarkable effect even if only a small amount is used. For example, when used as a flocculant for clarifying and concentrating suspensions, it can improve the capacity of suspension processing facilities, and when used for dewatering sludge, it can accelerate the dewatering rate and improve the water content of dehydrated cakes. Since the present invention is effective in improving the combustion efficiency of the dehydrated cake by reducing the combustion rate, the industrial value of the present invention is very large. Furthermore, when the water-soluble polymeric substance produced by the method of the present invention is used as a flocculant, its flocculating performance is superior to that produced by conventional production methods with a similar degree of polymerization. That is, even in the method of the present invention, the degree of polymerization of the produced polymer substance can be changed by changing the amount of polymerization initiator used during production, but the degree of polymerization obtained by the method of the present invention and the conventional method can be changed. Comparing the flocculation performance of the two water-soluble polymeric substances with the same degree of polymerization, it was found that the water-soluble polymeric substance produced by the method of the present invention was significantly superior despite having the same degree of polymerization. There is. The reason for this is that the acrylamide-based polymer material produced by the method of the present invention has the formula
This is thought to be due to the presence of the crosslinked structure represented by (1) or (2). Since water-soluble polymer substances with a high degree of polymerization have high viscosity as an aqueous solution, it is necessary to thoroughly mix them with the suspension to be flocculated during flocculation treatment, but depending on the flocculation equipment, this mixing may not be possible. If this is not done, the flocculating performance may not be fully exhibited. In such cases, if a water-soluble polymer substance obtained by the method of the present invention with a relatively low degree of polymerization is used, the viscosity of the aqueous solution is low, making it easy to mix with the suspension and prevent aggregation. Because of its excellent performance,
Effective flocculation processing can be performed using various flocculation devices. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto. Example 1 96 g of acrylamide, 40 g of a 10% aqueous solution of sodium acrylate, 0.5 ml of a 0.1% aqueous solution of glutaraldehyde, and 400 ml of distilled water were placed in the polymerization reactor of 1.
3.0 ml of a 0.1% aqueous solution of hydrogen peroxide and 9.0 ml of a 0.1% aqueous solution of ferrous sulfate were added as polymerization initiators while blowing nitrogen gas, and polymerization was carried out at 50°C for 3 hours. After the reaction was completed, the polymerization reaction rate measured by the bromine method was 99.8%. The degree of polymerization of the produced polymer substance is expressed in terms of viscosity.
In addition, the state of dissolution was measured by the filtration method. In other words, the viscosity is determined by taking a portion of the reaction solution, adding water in an amount that makes the concentration of the polymer substance produced 0.1%, and stirring the resulting solution for 5 hours. It was measured with The dissolved state of the polymeric substance was determined by passing the solution through a 100-mesh wire mesh and then visually observing the presence or absence of any undissolved polymeric material on the wire mesh. Table 1 shows the measured viscosity and dissolution state results. Hereinafter, a polymerization reaction was carried out under the same reaction conditions as in Example 1 while changing the amount of polymerization initiator used, and for comparison, a polymerization reaction was also carried out in the same manner without adding glutaraldehyde.
Copolymerized polymeric substances of acrylamide and acrylic acid shown in Example 2 and Comparative Examples 1, 2, and 3 were obtained.

[Table] In Comparative Example 3, in order to obtain a polymer substance whose solution viscosity was higher than that obtained in Comparative Example 2,
Although the polymerization reaction was carried out by further reducing the amount of the polymerization initiator used, a large amount of undissolved polymeric substances were present in the resulting polymeric substance solution. That is, when glutaraldehyde is not used, Comparative Example 2
It has been found that it is difficult to obtain a water-soluble polymer substance whose solution has a higher viscosity than the polymer substance obtained in . Example 3 Put 200 g of acrylamide, 2.5 ml of a 0.1% aqueous solution of fumardialdehyde, and 800 ml of distilled water into the polymerization reactor of Example 3, and add 10 ml of a 0.1% aqueous solution of t-butyl hydroperoxide as a polymerization initiator and hydroperoxide while blowing nitrogen gas. 8 ml of a 0.1% aqueous solution of sodium sulfite was added, and polymerization was carried out at 50°C for 3 hours. After the reaction was completed, the polymerization reaction rate measured by the bromine method was 99.7%. The viscosity of the polyacrylamide solution produced was 41.1 cp when measured in the same manner as described in Example 1. Comparative Example 4 A polymerization reaction was carried out in the same manner as described in Example 3, except that fumardialdehyde was not used. The viscosity of the resulting polyacrylamide solution was 26.3 cp. Example 4 30 g of acrylamide, 125 g of methacryloyloxyethyltrimethylammonium chloride, 1.5 ml of a 0.1% aqueous solution of adipraldehyde, and 250 ml of distilled water were placed in the polymerization reactor of Example 4 1, and 1% of t-butyl hydroperoxide was added while blowing nitrogen gas. Add 10 ml of aqueous solution and 3.5 ml of 1% aqueous solution of sodium hydrosulfite, and
Polymerized for hours. After the reaction was completed, the polymerization reaction rate measured by the bromine method was 98.3%. The viscosity of the solution of the copolymerized polymer material of acrylamide and methacryloyloxyethyltrimethylammonium chloride produced was 141 cp when measured in the same manner as described in Example 1 with the concentration of the solution being 0.2%. Comparative Example 5 A polymerization reaction was carried out in the same manner as described in Example 4 except that adipaldehyde was not used. The viscosity of the solution of the copolymerized polymer substance produced is
It was 102 cp. Coagulation test on bentonite suspensions Examples 1, 2 and 3 and Comparative Examples 1, 2 and 4
A flocculation test was conducted on bentonite suspensions of each of the water-soluble polymer substances obtained in the above, and the effects were compared. In the flocculation test, a 0.2% aqueous solution of each water-soluble polymeric substance was added to a 3% bentonite suspension in a measuring cylinder in an amount equivalent to 2.5mg per bentonite suspension as a water-soluble polymeric substance. A measuring cylinder was inverted to mix well, and after being allowed to stand still, the rate at which the flocs of flocculated bentonite settled was measured. The results are shown in Tables 2 and 3.

【table】

[Table] Coagulation test on surplus sludge A coagulation test on surplus sludge of each water-soluble polymer substance obtained in Example 4 and Comparative Example 5 was conducted. In the flocculation test for surplus sludge, 0.2% aqueous solutions of each water-soluble polymer substance are added in various amounts to surplus sludge from a sewage treatment plant, and the optimum amount of water-soluble polymer substances to be added is determined. This was done by measuring the removability of the dehydrated cake from the cloth and the moisture content of the dehydrated cake when the treated sludge was filtered through a cloth. The results are shown in Table 3.

[Table] The suspended solids concentration of the excess sludge was 1.7%, and the pH was 6.3. The optimum addition amount was determined from CST (capillary suction time) measured using Triton Model 131 equipment, and expressed as the amount of polymeric substance in the aqueous solution relative to the sludge. In addition, the peelability of the dehydrated cake was measured when the sludge treated with the optimal addition amount was centrifuged at 4000 rpm for 60 seconds using a 120 mesh nylon cloth, and the cloth was gently peeled off from the dehydrated cake separated on the cloth. This was indicated by the presence or absence of dehydrated cake adhering to the cloth. The moisture content of the dehydrated cake was determined by measuring the moisture in the dehydrated cake obtained in the peelability test by a drying method. Example 5 27.7 g of acrylamide, 418.9 g of a 35% aqueous solution of sodium acrylate, 0.195 ml of a 0.02% aqueous solution of glutaraldehyde, and distilled water were placed in the polymerization reactor of Example 5 1.
Add 53.5 ml of potassium persulfate 1% aqueous solution and 3.50 ml of sodium hydrosulfite 1% aqueous solution as polymerization initiators while blowing nitrogen gas.
1.75 ml was added and the polymerization reaction was carried out for 3 hours. The viscosity of the solution of the water-soluble polymer substance produced was 250 cp when measured in the same manner as described in Example 1.
It was hot. After the reaction was completed, the polymerization reaction rate measured by the bromine method was 99.5%. Comparative Example 6 A polymerization reaction was carried out in the same manner as in Example 5, except that glutaraldehyde was not used. The viscosity of the solution of the polymer substance produced was 205 cp. Example 6 103.7g of acrylamide was added to the polymerization reactor of 1.
290.8g of 10% aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate, 0.365ml of 0.02% glutaraldehyde aqueous solution, and 105.5ml of distilled water.
2,2'-azobis(2-amidinopropane) hydrochloride 10% aqueous solution 2.60ml, t-butyl hydroperoxide 2% aqueous solution 0.13ml, sodium hydrosulfite 1. % aqueous solution and 0.065 ml of a 1% ferrous sulfate aqueous solution were added, and a polymerization reaction was carried out for 3 hours. The polymerization reaction rate measured by the bromine method after the completion of the reaction was 99.9%. The viscosity of the solution of the polymer substance produced was as shown in Example 1.
When measured in the same manner as described in , it was 170 cp. Comparative Example 7 A polymerization reaction was carried out in the same manner as in Example 6 except that glutaraldehyde was not used. The viscosity of the solution of the polymer substance produced was 160 cp. Example 7 85.4 g of acrylamide, 53.8 g of a 55% aqueous solution of methacryloyloxyethyltrimethylammonium methyl sulfate, 0.301 ml of a 0.02% aqueous solution of glutaraldehyde, and distilled water were placed in the polymerization reactor of Example 7 1.
After adjusting the pH of the mixture to 4.0, add 2.3 ml of 10% aqueous solution of 2,2'-azobis(2-amidinopropane) hydrochloride and 1% aqueous potassium persulfate solution as polymerization initiators while blowing nitrogen gas.
1.73ml and sodium hydrosulfite 1
% aqueous solution was added and the polymerization reaction was carried out for 6 hours. After the reaction was completed, the polymerization reaction rate measured by the bromine method was 99.8%. The viscosity of the solution of the water-soluble polymer substance produced was 260 cp when measured in the same manner as described in Example 4.
It was hot. Comparative Example 8 A polymerization reaction was carried out in the same manner as in Example 7 except that glutaraldehyde was not used. The viscosity of the solution of the polymer substance produced was 260 cp. Example 8 78.6 g of acrylamide, 90.4 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride, and glutaraldehyde were placed in the polymerization reactor of 1.
Add 0.554ml of 0.02% aqueous solution and 331ml of distilled water,
After adjusting the pH of the mixture to 3.0, 3.75 ml of a 3% aqueous solution of ammonium persulfate and 1.87 ml of a 3% sodium hydrosulfite solution were added as polymerization initiators while blowing nitrogen gas, and a polymerization reaction was carried out for 3 hours. After the reaction was completed, the polymerization reaction rate measured by the bromine method was 99.5%. The viscosity of the solution of the produced water-soluble polymer substance was 510 cp when measured in the same manner as described in Example 4.
It was hot. Comparative Example 9 A polymerization reaction was carried out in the same manner as in Example 8 except that glutaraldehyde was not used. The viscosity of the resulting polymeric substance solution was 476 cp. Example 9 93 g of acrylamide, 27.9 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride, and glutaraldehyde were placed in the polymerization reactor of 1.
Add 0.327ml of 0.02% aqueous solution and 380ml of distilled water,
After adjusting the pH of the mixture to 3.0, while blowing nitrogen gas, a 10% aqueous solution of 2,2'-azobis(2-amidinopropane) hydrochloride was used as a polymerization initiator.
2.3ml, t-butyl hydroperoxide 2%
0.92 ml of an aqueous solution and 0.92 ml of a 1% aqueous solution of sodium hydrosulfite were added, and a polymerization reaction was carried out for 3 hours. After the reaction was completed, the polymerization reaction rate measured by the bromine method was 99.8%. The viscosity of the solution of the water-soluble polymer substance produced was 340 cp when measured in the same manner as described in Example 4.
It was hot. Comparative Example 10 A polymerization reaction was carried out in the same manner as in Example 9 except that glutaraldehyde was not used. The viscosity of the solution of the polymer substance produced was 320 cp. Coagulation test for bentonite suspension Examples 5, 6, 7, 8 and 9 and Comparative Example 6,
A flocculation test was conducted on a bentonite suspension of each of the water-soluble polymer substances obtained in 7, 8, 9, and 10, and the effects were compared. The aggregation test was conducted in the same manner as described in Section 15 using the amounts added in Table 5. The results are shown in Table 5.

【table】

Claims (1)

[Claims] 1. An aliphatic dialdehyde represented by the general formula OHC-R-CHO (in the formula, R represents an alkylene group or an alkenylene group) is added to an acrylamide monomer in an amount of 10 ^-5 to 10 ^- A method for producing an acrylamide-based water-soluble polymer substance, which comprises polymerizing an acrylamide-based monomer in an aqueous medium in the presence of ² mol%. 2. The method according to claim 1, wherein the reaction is carried out in an aqueous solution. 3. The method according to claim 1, wherein the aliphatic dialdehyde is malonaldehyde, succinaldehyde, malealdehyde, fumaraldehyde, glutaraldehyde, or adipaldehyde.