JPH05255565A - Powdery cationic water-soluble polymer composition and its production - Google Patents

Abstract

PURPOSE:To obtain the title composition of an excellent flocculating performance and high stability by neutralizing the strong acid remaining in a specified polymer after hydrolysis and mixing the recovered powdery polymer with a solid water-soluble organic acid. CONSTITUTION:The title process is one comprising producing a powdery cationic water-soluble polymer by polymerizing a monomer mixture containing an N- vinylcarboxamide of the formula: CH2=CHNHCOR (wherein R is H or CH3) (e.g. N-vinyl-formamide) and hydrolyzing the obtained polymer with a strong acid (e.g. hydrogen chloride), wherein a basic compound (e.g. calcium carbonate) in an amount at least equivalent to that of the strong acid remaining after the hydrolysis is added to the system, and a solid water-soluble organic acid is added to the recovered and separated powdery polymer. The obtained polymer has an excellent performance in use such as a flocculant, and this performance can stably persist even when the polymer is in a state of an aqueous solution.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a powdery cationic water-soluble polymer composition and a method for producing the same. For more information,
The present invention relates to a composition in which a specific acid is mixed with a powdery cationic water-soluble polymer obtained by acidic hydrolysis of a (co) polymer of N-vinylcarboxylic acid amide, and a method for producing the same.

[0002]

2. Description of the Related Art Cationic water-soluble polymers containing vinylamine units are expected to be used as flocculants and paper chemicals, which have excellent effects over conventional products. The cationic water-soluble polymer is generally produced by polymerizing N-vinylcarboxylic acid amide alone or another ethylenically unsaturated monomer and then hydrolyzing it with a strong acid ( JP-B-63-952
3, JP-A-62-74902, JP-A-63-21871
8 etc.).

As one of the problems in the above-mentioned method for producing a polymer, a part of the strong acid used in the hydrolysis remains in the polymer, and the steps such as separation, drying and transfer in producing the polymer are carried out. There is a point that devices are easily corroded. Therefore, in order to solve such a problem, it is conceivable to add a basic compound to the polymer after hydrolysis to neutralize the residual acid.

[0004]

However, the product cationic water-soluble polymer which employs the above method has a drawback that its stability in water is lowered. That is, a cationic water-soluble polymer is usually dissolved in water at the time of use and left for a long time in many cases.However, in a polymer neutralized with a basic compound, the cationization rate in an aqueous solution changes with time. There is a problem that the properties tend to be deteriorated, and various physical properties expected of the polymer such as aggregation performance are deteriorated.

[0005]

Means for Solving the Problems As a result of intensive studies made by the present inventors in view of the above circumstances, the strong acid remaining in the polymer after hydrolysis was once neutralized with a basic compound, and the powder after recovery was recovered. It has been found that the stability of the polymer in water is ensured by adding a specific acid to the polymer.

That is, the gist of the present invention is as follows.

[0007]

Embedded image Hydrochloric acid hydrolyzate of a (co) polymer of N-vinylcarboxylic acid amide represented by CH ₂ ═CHNHCOR (wherein R represents a hydrogen atom or a methyl group) and sulfamic acid. And a cationic water-soluble polymer composition in powder form.

Secondly, the general formula

[0009]

Embedded image A monomer containing an N-vinylcarboxylic acid amide represented by CH ₂ ═CHNHCOR (wherein R represents a hydrogen atom or a methyl group) is polymerized and hydrolyzed with a strong acid to obtain a powdery cation. In the method for producing a water-soluble polymer, after the hydrolysis,
A powdery cationic aqueous solution characterized by adding an equivalent amount or more of a basic compound to the strong acid remaining in the hydrolysis system, and then adding a solid water-soluble organic acid to the separated and recovered powdery polymer. And a method for producing a water-soluble polymer composition.

The present invention will be described in detail below. General formula used in the present invention

[0011]

Embedded image Examples of the N-vinylcarboxylic acid amide represented by CH ₂ ═CHNHCOR (wherein R represents a hydrogen atom or a methyl group) include N-vinylformamide and N-vinylacetamide. -For the purpose of obtaining a modified product of a vinylcarboxylic acid amide polymer, N-vinylformamide is preferable because the polymer has good hydrolyzability.

The cationic water-soluble polymer used in the present invention is a product obtained by polymerizing the above-mentioned N-vinylcarboxylic acid amide-containing monomer, and subsequently subjecting the resulting polymer to acidic hydrolysis. The content ratio of N-vinylcarboxylic acid amide in the raw material monomer is usually 20.
It is at least mol%, preferably at least 40 mol%. Also,
As the comonomer component, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide,
Acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, vinyl acetate and the like can be mentioned, with preference given to acrylonitrile.

As the method for polymerizing the raw material monomer, any of bulk polymerization, aqueous solution precipitation polymerization and suspension polymerization can be carried out, but a method of polymerizing the monomer in a solvent is preferable. As a method for polymerizing in an aqueous solution, polymerization is started in a solution state under the condition of a monomer concentration of 5 to 20% by weight, and a polymer is obtained as a precipitate, or polymerization is started under the condition of a monomer concentration of 20 to 60% by weight. The method of obtaining a hydrogel of the polymer or a precipitate of the polymer is exemplified.

In the suspension polymerization method, the aqueous solution concentration of the raw material monomer is usually 5 to 95% by weight, preferably 20.
To 80% by weight, and usually 0.5 to 1 with respect to the aqueous solution.
A water-insoluble hydrocarbon solvent in an amount of 0 times by weight, preferably 1 to 5 times by weight, is used as a dispersion medium to obtain a uniform granular polymer. As the hydrocarbon-based dispersion medium, a hydrocarbon azeotropic with water is preferable. For example, chain saturated hydrocarbon such as n-hexane, n-heptane, n-octane, nonane, decane, undecane, dodecane, petroleum fraction having a boiling point of 65 to 250 ° C, preferably petroleum fraction having a boiling point of 80 ° C to 180 ° C,
Examples thereof include alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene.

In suspension polymerization, an oil-soluble polymer or a general surfactant is usually used as a dispersion stabilizer. Examples of the non-emulsifiable oil-soluble polymer include oil-soluble celluloses such as ethyl cellulose and hydroxyethyl cellulose, and adducts of olefins with maleic anhydride. The surfactant is preferably H.I. L. B. A nonionic surfactant having a ratio of 9 or more, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, etc. is used.
The amount of the above dispersion stabilizer used is usually 0.01 to 5% by weight, preferably 0.05 to 1% by weight, based on the dispersion medium.

As the polymerization initiator, a general radical polymerization initiator can be used, but an azo compound is preferable. Particularly preferred is a water-soluble azo compound,
2,2'-azobis-2-amidinopropane hydrochloride,
Sulfates and acetates, azobis-N, N'-dimethyleneisobutylamidine hydrochlorides, sulfates and acetates,
Examples thereof include alkali metal salts and ammonium salts of 4,4′-azobis-4-cyanovaleric acid. The radical polymerization initiator is usually 100 to 10000 ppm, preferably 500 to 5000, on a weight basis with respect to the raw material vinyl compound.
Used in the ppm range.

The polymerization temperature is usually 30 to 100 ° C.,
The polymerization time is 0.5 to 10 hours, preferably 1 to
8 hours. During the polymerization, heat of polymerization is generated, and therefore the polymerization temperature is usually adjusted by cooling the polymerization system so that the polymerization temperature is maintained within the above range. The polymer obtained by the above method is subsequently subjected to hydrolysis in the presence of a strong acid. Examples of the strong acid include hydrogen chloride, hydrogen bromide, hydrogen fluoride, sulfuric acid, nitric acid and the like, but preferably hydrogen chloride (in the present invention, hydrolysis using hydrogen chloride is widely referred to as “hydrochloric acid hydrolysis”). The introduction form of the reaction system may be gaseous or hydrochloric acid aqueous solution. The amount of the strong acid used is usually 0.5 to 4 times equivalent, preferably 1 to 2 times equivalent to the formyl group or acetamide group of the polymer.

As a specific method of hydrolysis, a strong acid is added to a solution or dispersion containing a polymer and the mixture is stirred, or the polymer recovered as a powder is sprayed with a strong acid or a gas. And a method of circulating a strong acid in the form of a circle. The hydrolysis temperature is usually 20 to 150.
C., preferably 60 to 130.degree. C., and the reaction time is usually selected from the range of 0.5 to 10 hours.

The present invention requires the addition of a basic compound to the above reaction mixture after hydrolysis. That is, it is intended to neutralize the strong acid remaining in the system and prevent equipment corrosion when the hydrolyzed polymer is handled in the subsequent steps. As the basic compound,
Usually, weakly basic salts such as alkali metal or alkaline earth metal carbonates or bicarbonates are mentioned, and calcium carbonate is particularly preferable. The amount of the basic compound used here is an equivalent or more, preferably 1 to 5 times the equivalent of the strong acid remaining in the system after hydrolysis. In this addition treatment of the basic compound, it is usually preferable that the basic compound is directly added to the polymer after hydrolysis and uniformly mixed. For example, when hydrolysis is performed in the dispersion medium, a predetermined amount of basic compound may be added to the dispersion medium and mixed. The mixing treatment temperature is usually 20 to 90 ° C.

The polymer after addition of the basic compound is
Then, if necessary, according to a known method, treatments such as dehydration, filtration, granulation, and drying are performed to separate and collect the powdery cationic water-soluble polymer as a product. In the present invention, the powdery polymer is used. On the other hand, a method of adding a water-soluble organic acid that is solid at room temperature is preferable. Examples of the water-soluble organic acid include sulfamic acid, oxalic acid, fumaric acid, succinic acid, malonic acid, citric acid, and adipic acid, but sulfamic acid is preferable from the viewpoint of odor and price.

The amount of the water-soluble organic acid added is determined according to the amount of the basic compound used for the neutralization. When the cationic polymer of the present invention is dissolved in water to form a 0.1% by weight aqueous solution. The pH may be usually 6 or less, preferably 5 or less. The upper limit of the addition amount is not particularly limited, but is usually 0.1 to 2 with respect to the total amount of the polymer and acid.
It is 0% by weight, preferably 0.5 to 10% by weight. When the amount of the acid added is small and the pH is 6 or more, the stabilizing effect of the polymer becomes small.

The method of blending the above powdery polymer is
Although not particularly limited, it can be usually carried out by a dry blending method in which a water-soluble organic acid is added in powder form and mixed. Industrially, a method of adding an acid while stirring a polymer with a rotating drum or the like is exemplified. The composition produced by the above method is usually used as an aggregating agent in the form of a 0.01 to 30% by weight aqueous solution.

[0023]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Examples 1 to 6, Comparative Example 1 Cyclohexane 400 was placed in a 2-liter 4-necked flask equipped with a stirrer, a cooling tube, a dropping funnel, and a nitrogen gas introducing tube.
g, polyoxyethylene oleyl ether (Daiichi Kogyo Seiyaku Co., Ltd., trade name “Neugen ET140E”, HL.
B. = 14.0) 2.6 g, ammonium chloride 5.5 g
Was added and the temperature was raised to 60 ° C. with stirring.

Next, under a nitrogen gas stream, 60 g of water, 2,
2'-azobis-2-amidinopropane dihydrochloride 0.1
2 g, N-vinylformamide (purity = 91.5%) 6
A mixed solution of 0 g and 45 g of acrylonitrile (purity = 99.5%) was added dropwise with stirring over 3 hours. After that, the reaction was further continued for 2.5 hours. Furthermore, 1.2 times equivalent of hydrogen chloride gas was blown into N-vinylformamide, the temperature was raised to 100 ° C. in a sealed system, and hydrolysis was carried out for 4 hours under stirring.

Next, after allowing to cool to near room temperature, about 2 times equivalent of calcium carbonate in excess of hydrogen chloride (0.2 times equivalent to N-vinylformamide) is added for neutralization and then azeotropic. Water was removed by dehydration, and the powdery polymer was collected by filtration. About the obtained polymer, the acid shown in Table 1 was added and mixed, and then a 0.1 wt% aqueous solution was prepared, and the pH at the time of preparation and the change with time of the cationization rate of the polymer after preparation were examined. Is shown in Table-1.

The method of measuring the cationization rate is as follows. That is, 5.0 g of the above sample solution was diluted with demineralized water to 2200 ml, and the pH of the solution was adjusted to 3.
After adjusting to 0, the cationization rate is calculated by the colloid titration method using toluidine blue as an indicator using 1/400 normal potassium polyvinyl sulfate.

[0027]

[Table 1]

Next, an aggregation performance test was conducted on the above-mentioned polymer aqueous solution. That is, 200 ml of 100 ml of excess sludge (solid content 1.51%) of a commercial activated sludge treatment facility is used.
The mixture was placed in a beaker of ml, and then 10 ml of each of the above polymer aqueous solutions (4 hours and 24 hours after preparation) was added. Stirring was carried out at 1000 rpm for 10 seconds using a stir bar having three round bars each having a diameter of 5 mm and a length of 20 mm attached to the tip.
The coagulated sludge was filtered with a 60-mesh nylon filter cloth by gravity filtration, and the filterable amount (filtered water amount) was measured in a filtration time of 60 seconds.

The sludge after gravity filtration is a 30 cm square polyester monofilament filter cloth (OLh- manufactured by Nippon Filcon).
C) It was sandwiched between two sheets and further sandwiched by a polyvinyl chloride plate having a drainage groove, and was hydraulically pressed with a piston diameter of 20 mm to maintain a pressurizing condition of a piston pressure of 50 kg / cm ² for 30 seconds for press dehydration. The water content of the dehydrated sludge was determined from the weight of the dehydrated sludge and the weight of the sludge solid content after drying at 120 ° C. for 3 hours.
The measurement results of the drainage amount and the water content are shown in Table-2.

[0030]

[Table 2]

[0031]

The cationic water-soluble polymer produced according to the present invention has excellent performance in applications such as a flocculant, and since the performance is stably maintained even in a polymer aqueous solution, it is very practical. Is.

Claims (2)

[Claims] 1. A hydrochloric acid hydrolyzate of a (co) polymer of N-vinylcarboxylic acid amide represented by the general formula: CH ₂ ═CHNHCOR (wherein R represents a hydrogen atom or a methyl group). And a cationic water-soluble polymer composition in the form of a powder, comprising: and sulfamic acid. 2. A monomer containing an N-vinylcarboxylic acid amide represented by the general formula: CH ₂ ═CHNHCOR (wherein R represents a hydrogen atom or a methyl group) is polymerized and hydrolyzed with a strong acid. In the method of producing a powdery cationic water-soluble polymer by decomposing, after the hydrolysis,
A powdery cationic aqueous solution characterized by adding an equivalent amount or more of a basic compound to the strong acid remaining in the hydrolysis system, and then adding a solid water-soluble organic acid to the separated and recovered powdery polymer. For producing a water-soluble polymer composition.