JPH0617387B2 - Method for producing aminomethylated high molecular weight polyacrylamide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an aminomethylated polyacrylamide having a high molecular weight and a high degree of cationization. More specifically, two types of polyacrylamide having high and low intrinsic viscosities are used as base polymers,
After mixing in a certain range of ratio and adding powdered fat and oil, the second
Aqueous primary amine solution is added to obtain a water-swelling gel body, and thereafter,
After completion of the Mannich reaction by adding aldehyde while kneading, if necessary, the water-swollen gel body is continuously supplied to a pulverizer and pulverized into a sized finely divided gel body, followed by drying. And a method for producing an aminomethylated polyacrylamide having a high molecular weight and a high degree of cationization.

As a characteristic feature of aminomethylated polyacrylamide, polyacrylamide, secondary amine, aldehyde, etc., which are raw materials, are relatively inexpensive and are widely used as an excellent cationic sewage sludge treatment agent.

Further, it is often used as a paper-strengthening agent, a water-based improving agent, and a sedimentation-clarifying agent for suspensions.

Particularly recently, the aminomethylated polyacrylamide has been used for sludge mixed with excess sludge and coagulated sedimentation sludge.
It is known that it is possible to improve the dehydration property of sludge, and it is receiving attention again.

However, the aminomethylated polyacrylamide is often manufactured as a liquid product for various reasons, but the aminomethylated polyacrylamide as a liquid product lacks stability and is difficult to store for a long period of time. Yes,
Further, since the liquid product concentration is low, it is the current situation that the expansion of demand is hindered due to the poor transport efficiency. Therefore, as a countermeasure against this, some proposals have been made so far for the purpose of producing an aminomethylated polyacrylamide powder or solid that is easy to handle and has good storage stability. Has a relatively low molecular weight and a low degree of cationization,
It contains fine powder that causes dust dust that is not desirable in the field, and the particle size distribution ranges from fine powder to coarse powder.
There are unfavorable points in the dissolution operation, and the water solubility is generally inferior.
There are points to be improved and inconveniences, and it has been desired to solve these problems.

The present inventors have arrived at the present invention as a result of intensive research to solve these problems.

That is, according to the present invention, when polyacrylamide is subjected to Mannich modification with a secondary amine and an aldehyde to produce an aminomethylated polyacrylamide having a high cationization degree, a high molecular weight and a low molecular weight having different intrinsic viscosities are obtained. 2 types of polyacrylamide are mixed, and a base polymer whose intrinsic viscosity and mixing ratio satisfy the following formula is selected, [In the above formula, X ₁ and [η] ₁ are the ratio [−] of the mixing ratio of the base high-molecular-weight polyacrylamide and the intrinsic viscosity [dl / g] of the polyacrylamide, and
₂ and [η] ₂ are the ratio [−] of the mixing ratio of the low molecular weight polyacrylamide as the base and the intrinsic viscosity [dl / g] of the polyacrylamide.] 2.0% by weight with respect to the base polymer ~ 5.0 wt% cyclodextrin and a water-soluble emulsion of fats and oils were added to powdered fats and oils, and a secondary amine aqueous solution was added to the prepared mixture of base polymer and powdered fats and oils to give a base polymer concentration. Aldehyde is added to this water-swelling gel body so that the amount becomes 30 to 50% by weight,
The Mannich reaction is performed, and if necessary, the water-swollen gel body of the Mannich reaction product is continuously supplied to a pulverizer to have a particle size of 0.5 m / m to 1.0 m / m.
The present invention provides a method for producing an aminomethylated polyacrylamide having a high molecular weight and a high degree of cationization, which comprises sizing to m and drying.

According to the present invention, aminomethyl of finely powdered polyacrylamide having a high molecular weight, a high degree of cationization, and a preferable particle size distribution, which have not been obtained in the prior art, and is sized, is obtained. Compounds can be produced, further excellent water solubility can be imparted, and storage stability can be further improved, and various problems of the prior art can be summarized at once. I was able to solve it.

As the mixing ratio and the intrinsic viscosity of the polyacrylamide having high and low molecular weights within the ranges satisfying the above formulas (1), (2) and (3), for example, for polyacrylamide having a high molecular weight, X ₁ = 0.73 to 0.80 [η] ₁ = 7.9 to 9.1 [dl / g] On the other hand, for polyacrylamide having a low molecular weight, X ₂ = 0.27 to 0.20 [η] ₂ = 2.5 to 4 It is indispensable to be in the range of 0.3 [dl / g].

Thus, polyacrylamide with high molecular weight,
Infinitely high intrinsic viscosity should not be selected,
It should be kept in the range of 9.1 [dl / g],
The proportion in the mixture of two high and low molecular weight polyacrylamides (base polymer) should also be kept at 73% to 80%. On the other hand, low molecular weight polyacrylamide has an intrinsic viscosity of 2.5 to 4.3 [dl / g].
Should be selected and should be kept at 20% to 27%.

When such two types of polyacrylamide having intrinsic viscosities are mixed in such a range, the obtained polyacrylamide is used as a base, and the mechanical cleavage of the molecular chain (decrease in molecular weight) due to the kneading operation required during the Mannich reaction is minimized. As a result of increasing the chances of mutual contact between the reaction product polyacrylamide and the secondary amine and aldehyde, the Mannich reaction proceeds smoothly, and the molecular weight and cationization degree are higher than those of conventional methods. It has been found that a polyacrylamide aminomethylated product is obtained.

Beyond the ranges defined by the above formulas (1), (2), and (3), for example, when only polyacrylamide having a too high intrinsic viscosity is used as the base polymer, the resulting Mannich modified product in a water swollen state is All of them have poor solubility in water, cannot impart favorable water solubility, and when using only polyacrylamide having a too low intrinsic viscosity, a Mannich-modified product in a water-swelling state having a low molecular weight is obtained, and a medium degree. Even when using a polyacrylamide of intrinsic viscosity of as a base polymer, it remains a Mannich modified product with a medium molecular weight and cationization degree, and a desired high molecular weight,
Moreover, it is not possible to obtain a Mannich modified product in a water-swelling state having a high degree of cationization. As described above, the combination of the mixing ratio and the intrinsic viscosity selected in the present invention is the first essential requirement.

Second, in addition to the first essential requirement, it is necessary to add 2.0 to 5.0% by weight of powdered fat and oil to the base polymer and mix them uniformly.

The powdered fat and oil in the present invention is a cyclic oligosaccharide,
Unimolecular host molecule having a hydrophobic cavity in the molecule [h
guest molecule [guest molecule] that enters into the cavity as
A cyclone that has the ability to incorporate (embrace), has a hydrophobic environment similar to dioxane consisting of CH bonds and ether bonds inside the cavity, while having a hydrophilic property outside the cavity due to the arrangement of hydroxyl groups. Dextrin (which may be any of α, β and γ type) and commercially available fats and oils, for example, palm oil (constituent fatty acid having 14 to 18 carbon atoms), or palm kernel oil (constituent fatty acid having 8 to 18 carbon atoms), Then, by mixing water and stirring for several hours, an oil and fat inclusion is obtained, which is then produced by drying it to remove water.

The powdered fats and oils thus obtained are white, chemically stable inclusions and are rendered hydrophilic, and the powdered fats and oils are 1 mol of β-cyclodextrin and 1 mol of palm oil.
Although the equimolar clathrate having a ratio of is generally used, the equimolar clathrate is not limited to this equimolar clathrate, and the ratio is within a certain range and can be arbitrarily changed. The powdery fats and oils thus obtained have good dispersibility in water, and a large increase in hydrophilicity can be expected due to the hydrophilicity of the outer cavity of the inclusion.

Next, to the treated base polymer in the kneader, water is added so that the concentration of the secondary amine is 30 to 50%, and after the polymer is sufficiently swollen, the aldehyde is mixed while kneading. Is added to carry out the Mannich reaction.
The ratio of secondary amine and aldehyde to be added here is
A molar ratio of 1: 1 is more preferable, and a molar ratio of polyacrylamide: secondary amine: aldehyde is usually
It is 1: 1: 1.

This water-swollen polyacrylamide gel body is a mixture of high and low molecular weights mixed in an optimum ratio for kneading, and has an excellent friction-reducing effect on kneading of a water-swelling polymer contained in the powdered fat and oil added. Thereby, the Mannich denaturation is extremely smoothly performed with the mechanical chain breaking minimized.

The present invention relates to various methods employed in the prior art for facilitating kneading in the Mannich modification, for example, a method of mixing a large amount of a salt with a base polymer as an aqueous solution [see USP 4.1110.520], , Adding a surfactant to the base polymer as an aqueous solution [Japanese Patent Publication No.
9-50682], a significantly superior kneading effect can be given to the Mannich reaction. By these effects,
High molecular weight [molecular weight 40
A powdered Mannich modified product having a viscosity of 00000, an intrinsic viscosity of 8.3 dl / g] and a high cationization degree [cationization rate of 5.9 meq / g] can be obtained.

By the way, a conventional powdered solid Mannich modified product has a low molecular weight of 3,000,000 [intrinsic viscosity of 7.2 dl / g] and a degree of cationization [cationization rate of 3.6 meq / g].

The Mannich modified product in a water-swelled state after the reaction shows a gel-like and soft rubber elasticity, but according to the present invention, it is less sticky and can be continuously extruded from a kneader by an ordinary extrusion method, for example, an ejector. Will be taken out.

Next, if necessary, the water-swollen gel body of the Mannich reaction product is supplied to a grinder.

The water-swelled Mannich modified product is easily sized to a particle size of 0.5 m / m to 1.0 m / m by the crusher and discharged from the hole of the crusher screen. In this crusher, the crushing heat generated by crushing is replaced with the latent heat of evaporation consumed by the evaporation of water contained in the Mannich modified product in a water-swelling state, and the temperature rise of the crushed object can be prevented.

The Mannich modified product pulverized so as to have a desired particle size distribution is pulverized without being deteriorated in water solubility by pulverization heat, and then supplied to an ordinary dryer and dried. What should be done is that the material to be dried (Mannich modified product) can be made to have the same particle size between 24 mesh pass and 60 mesh on, so that the drying time can be significantly shortened and It is possible to prevent deterioration. That is, the Mannich-modified product, which has been shortened in the drying heat treatment time by the short-time drying, has less chance of water-soluble deterioration correspondingly, and can be dried quickly while maintaining the water-solubility.

As described above, according to the present invention, not only the water solubility of the powdery aminomethylated ponoacrylamide is maintained, but also the long-term storage stability is remarkably excellent.

The present invention will be specifically described below with reference to examples.

Example 1 As shown in Table 1 consisting of a combination of two kinds of powdery polyacrylamide having different molecular weights, each was prepared so that the total amount of polyacrylamide would be 800 g.

Powdered oils and fats are prepared by using either palm oil [constituent fatty acids having 14 to 18 carbon atoms] or palm kernel oil [constituent fatty acids having 8 to 18 carbon atoms] as fats and oils, and α, β and γ types as cyclodextrins. It is prepared by the following method using any of the above.

Oil / fat: β-cyclodextrin: water = 1: (1-1
0): (ratio in the range of 1 to 10, preferably fat and oil: β
-Mix in a ratio of cyclodextrin: water = 1: 5: 8, stir at room temperature for about 2 hours, remove water with an ordinary dryer at 80 ° C, and dry for about 3 hours to remove water. 5%
Reduced to The β-cyclodextrin used here is the product name “Celdex” manufactured by Nippon Shokubai Co., Ltd.
Is. When the obtained dried product is pulverized by a small pulverizer, it becomes a white fine powdery oil and fat.

32.0 g of the powdered fats and oils obtained as described above was mixed with the base polymer and mixed with a jacketed uniaxial stirring type 10
A stainless steel ribbon blender having a capacity of 1 is charged.

While rotating the ribbon blender, 1,666 g of water was charged and 96.0 g of 50% dimethylamine aqueous solution was charged, and stirring was continued for about 1 hour, and the temperature was raised to 50 ° C.

Furthermore, after stirring for 30 minutes, the base polymer becomes a swollen gel body containing water. While continuing stirring, 81 g of a 37% aqueous formalin solution was added dropwise over 35 minutes while maintaining the temperature at 50 to 60 ° C. At this time, the solid content concentration is about 3
It is kept at 1.0%.

As shown in Table-1, intrinsic viscosity [η] ₁ = 8.6 [dl /
g] and a low molecular weight powdered polyacrylamide [molecular weight of about 4,000,000] and an intrinsic viscosity [η] = 3.8 [dl / g] [molecular weight of about 12].
Table 2 shows the physical property values of the water-swollen Mannich modified product prepared by a conventional method by adding powdered palm oil to polyacrylamide, which is a mixture of polyacrylamide and various amounts of polyacrylamide.

As is clear from Table-2, in order to obtain a water-swelled Mannich-modified product with a water-insoluble content as small as possible [practically 0.2% or less] and an intrinsic viscosity as high as possible, it is generally high. As the ratio of the molecular weight base polymer,
The range of X ₁ = 0.75 to 0.80 is more preferable. Thus, the proportion of low molecular weight base polymer is X ₂ = 0.25-0.25.
It is limited to the range of 0.20.

Example 2 The water-swelled Mannich modified product obtained in Example 1 was fed to a crusher (using a screen hole diameter of about 1.0 mmφ) with a screw type extruder at a rate of 1.8 kg / hr. To do.

The Mannich modified product in the water swollen state discharged from the crusher has an average diameter of 0.9 to 1.0 mmφ,
Particles having an extremely fine particle size and no fine powder content were obtained.

A water-containing Mannich modified gel having a uniform particle size containing about 35.0% of water is placed on a 100 mesh stainless wire net, and hot air at about 50 ° C. is blown for 120 minutes to contain 9.2% of water. An aminomethylated product of powdered polyacrylamide was obtained. The powder had a fine powder content of 0 in 200 mesh pass, and the fraction occupied by 16 mesh on product to 60 mesh on product was 96.5%.

The analytical values of this powder are shown in Table 3.

From these results, the amount of insoluble matter is small [practically 0.
2% or less], high intrinsic viscosity, and high cationization rate [high colloid equivalent value] In order to obtain an aminomethylated product of powdered polyacrylamide, it is more preferable to use X ₁
It can be confirmed that it is necessary to select the range of 0.75 to 0.80.

Example 3 A combination of two types of powdered polyacryamide having different molecular weights by a thermal polymerization method using a known thermal polymerization initiator, for example, a redox-based catalyst such as ammonium persulfate-triethanol, was used. The results are almost the same as those shown in Table 2, that is, X ₁ = 0.75 to 0.80 and X ₂ = 0.
It was confirmed that the range of 25 to 0.20 gives a Mannich-modified gel in a water-swelling state having a very low insoluble content and a high molecular weight.

Example 4 The water-swollen Mannich-modified gel obtained in Example 3 [thermal polymerization method] was subjected to the same pulverization and drying treatment as in Example 1 [photopolymerization method] to obtain a dimethylamino compound of powdered polyacrylamide. The analysis values are the same as in Table-3: X ₁ = 0.75 to 0.80, X ₂ = 0.25 to 0.20
At the time of, the insoluble content was as low as 0.08 to 0.10 (%),
Good water solubility, intrinsic viscosity = 8.1-8.4 (dl / g)
And the colloid equivalent value = 5.8 to 5.9 (meg /
g), which was extremely high and excellent.

Comparative Example 1 In both cases of the conventional photopolymerization method and thermal polymerization method, [η] ₁ = 7.9 to 9.1 [dl / g] [η] ₂ = the base polymer high-low molecular weight polyacrylamide was used. Other than 2.5 to 4.3 [dl / g], and the mixing ratio was set to a ratio other than X ₁ = 0.73 to 0.80 X ₂ = 0.27 to 0.20, and Example 1 A large number of powdered polyacrylamide aminomethylated products were obtained by the same procedure as described above, but the intrinsic viscosity of No. 5 of Example 1 was 8.3.
[Dl / g] and colloid equivalent value 5.9 [meg /
Nothing above g] was obtained.

Claims (1)

[Claims] 1. When a Mannich modification of polyacrylamide with a secondary amine and an aldehyde is carried out to produce an aminomethylated polyacrylamide having a high molecular weight and a high cationization degree, a high molecular weight and a low molecular weight having different intrinsic viscosities. 2 types of polyacrylamide are mixed, and a base polymer whose intrinsic viscosity and mixing ratio satisfy the following formula is selected, [In the above formula, X ₁ and [η] ₁ are the ratio [−] of the mixing ratio of the base high-molecular-weight polyacrylamide and the intrinsic viscosity [dl / g] of the polyacrylamide, and
₂ and [η] ₂ are the ratio [−] of the mixing ratio of the low molecular weight polyacrylamide as the base and the intrinsic viscosity [dl / g] of the polyacrylamide.] 2.0% by weight with respect to the base polymer ~ 5.0 wt% cyclodextrin and a water-soluble emulsion of fats and oils were added to powdered fats and oils, and a secondary amine aqueous solution was added to the prepared mixture of base polymer and powdered fats and oils to give a base polymer concentration. Aldehyde is added to this water-swelling gel body so that the amount becomes 30 to 50% by weight,
The Mannich reaction is performed, and if necessary, the water-swollen gel body of the Mannich reaction product is continuously supplied to a pulverizer to have a particle size of 0.5 m / m to 1.0 m / m.
A method for producing an aminomethylated polyacrylamide having a high molecular weight and a high degree of cationization, which comprises sizing to m and drying.