JPH06104705B2 - Vinylamine copolymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] A novel polyvinylamine of the present invention, a vinylamine copolymer, is a flocculant for treating wastewater, a dehydrating agent for organic sludge,
It exhibits excellent effects in the application fields of cationic polymers such as drainage improvers, filler retention improvers and paper strength enhancers in the paper manufacturing industry.

[Conventional technology and its problems]

Conventionally, polyvinylamine is known to be produced by Hofmann decomposition of polyacrylamide and hydrolysis of polyN-vinylamide. In particular, the method of hydrolyzing a homopolymer of N-vinylformamide is an excellent method capable of synthesizing polyvinylamine having a high molecular weight and good stability. However, the obtained polymer had extremely high hydrophilicity, and the effect when used as a flocculating agent for dehydration was insufficient. A method is known in which N-vinylformamide and ethylene are preliminarily copolymerized and hydrolyzed in order to impart hydrophobicity to polyvinylamine. However, N-vinylformamide and ethylene have poor copolymerizability. In addition, it was difficult to obtain a high molecular weight copolymer, and this object could not be achieved by the copolymerization.

In addition, the present inventors firstly added N-vinylformamide,
Provided is an aggregating agent using a basic hydrolyzate of a copolymer of N, N-dialkyl (meth) acrylamide (JP-A-61)
-118406). However, this hydrolyzate becomes a quaternary copolymer containing a carboxyl group, and when used as a flocculating agent for dehydration, the water content of the dehydrated sludge could not be sufficiently reduced.

[Means for solving problems]

An object of the present invention is to provide a novel high molecular weight vinylamine copolymer to which hydrophobicity is imparted by partially modifying a specific N-vinylformamide copolymer under acidic conditions. And the above-mentioned object of the present invention comprises structural units represented by the following general formulas [I], [II] and [III], (In the formula, X represents an anion) (In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is 1 to 1 carbon atoms.
4 represents an alkyl group having 4 to 4 carbon atoms or an oxoalkyl group having 4 to 8 carbon atoms) The structural unit [I] has a mole fraction of 5 to 85 mol%, the structural unit [II] has a mole fraction of 5 to 85 mol%, and a structure Achieved by vinylamine copolymers in which the molar fraction of units [III] is 90 to 5 mol%.

The preferred composition of the vinylamine copolymer of the present invention is that the structural unit [I] has a mole fraction of 5 to 85 mol%, the structural unit [II] has a mole fraction of 5 to 85 mol%, and the structural unit [III]
The molar fraction of the structural unit [I] is 5 to 85% by mole, and the structural unit [II] is 5 to 85% by mole. %, And the molar fraction of the structural unit [III] is in the range of 40 to 10 mol%.

The vinylamine copolymer of the present invention generally has a reduced viscosity value of 0.1 to 10 dl / g, preferably 1 to 10 dl / g, when measured as a solution of 0.1 g / dl in 1N saline solution at 25 ° C. It is a polymer.

The vinylamine copolymer of the present invention can be easily obtained by modifying the formyl group in the following N-vinylformamide copolymer under acidic conditions. N- used as raw material
The vinylformamide copolymer is N-vinylformamide and the following general formula [IV] as a raw material of the structural unit of the general formula [III]. The molar ratio of the compound is usually 10:90 to 95: 5 mixture, preferably 40:60 to 95: 5 mixture, more preferably 60:40 to
It is a copolymer obtained by polymerizing a mixture of 90:10 in the presence of a radical polymerization initiator.

As the N-substituted acrylamide or N-substituted methacrylamide of the general formula [IV], R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is a carbon atom. C 1-4 alkyl group or C 4-8
A compound that is an oxoalkyl group of is used. For example, N-methyl acrylamide, N-ethyl acrylamide, Nn-propyl acrylamide, N-isopropyl acrylamide, Nn-butyl acrylamide,
N-isobutylacrylamide, Nt-butylacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N, N-di-n-propylacrylamide, N, N-di-n-butylacrylamide, N- (1,1
-Dimethyl-3-oxobutyl) acrylamide, N-
Methyl methacrylamide, N-ethyl methacrylamide, N-n-propyl methacrylamide, N-isopropyl methacrylamide, N-n-butyl methacrylamide, N-isobutyl methacrylamide, Nt-butyl methacrylamide, N, N- Dimethylmethacrylamide,
N, N-diethylmethacrylamide, N, N-di-n-propylmethacrylamide, N, N-di-n-butylmethacrylamide, N- (1,1-dimethyl-3-oxobutyl) methacrylamide, etc. To be Particularly preferred is N
-Isopropylacrylamide, Nt-butylacrylamide, N, N-dimethylacrylamide, N- (1,1-
Dimethyl-3-oxobutyl) acrylamide.

As the polymerization method for producing the above N-vinylformamide copolymer, any of bulk polymerization, precipitation polymerization and solution polymerization can be used, but solution polymerization is preferable, and aqueous solution polymerization is particularly preferable. . When the aqueous solution polymerization method is used, the molecular weight of the desired polymer, the concentration of the monomer in consideration of the heat of polymerization, the polymerization method, and the shape of the polymerization reactor are appropriately selected. Is done. That is, a method of polymerizing in a solution at a monomer concentration of 5 to 20% by weight, a method of polymerizing in a hydrogel state under a condition of a monomer concentration of 20 to 60% by weight, a monomer concentration of 20 to 60% by weight % Aqueous solution using a hydrophobic solvent and an emulsifier to polymerize in oil-in-water or water-in-oil emulsion state, monomer concentration 20-
An example is a method of polymerizing a 60% by weight aqueous solution in a dispersed state of water in oil using a hydrophobic solvent and a dispersion stabilizer.

As the radical polymerization initiator, any of the general initiators usually used for the polymerization of water-soluble or hydrophilic monomers is used, but in order to obtain a polymer in good yield, an azo compound is used. preferable. Particularly preferred are water-soluble azo compounds, examples of which include 2,2′-azobis-2-amidinopropane hydrochloride and acetate, 4,4′-azobis-4-cyanovaleric acid sodium salt. Salt, Azobis-N,
Mention may be made of N'-dimethyleneisobutylamidine hydrochloride and sulphate. The amount of these polymerization initiators used is usually in the range of 0.01 to 1% by weight based on the weight of the monomer. In addition, the polymerization reaction is generally carried out under an inert gas flow of 30 to 100.
It is carried out at a temperature of ° C.

The resulting N-vinylformamide copolymer is used as it is or in the form of a solution by diluting it, or by dehydration or drying by a known method to obtain a powder and then denaturing it under acidic conditions to give a new polyvinylamine. You can do it.

Examples of the modification method used in that case include a method of acidic hydrolysis in water, a method of acidic hydrolysis in a hydrophilic solvent such as alcohol containing water, a method of alcoholysis under acidic conditions, and the like. However, the preferred method is to modify the formyl group while separating it as a formate ester. By these methods, the modification reaction of the structural unit of the general formula [III] is suppressed, and a vinylamine copolymer containing substantially no carboxyl group is produced. As the modifier used here in the case of acidic modification, any compound that acts on strong acidity can be used,
Examples thereof include hydrochloric acid, bromic acid, hydrofluoric acid, sulfuric acid, nitric acid, phosphoric acid, sulfamic acid, alkanesulfonic acid and the like. The amount of the modifier used is usually in the range of 0.1 to 2 times the mol of the formyl group in the polymer, and is appropriately selected according to the target modification ratio. The alcohol used in the alcoholysis may be an alcohol having 1 to 4 carbon atoms, preferably methanol.

INDUSTRIAL APPLICABILITY The vinylamine copolymer of the present invention exhibits excellent effects such as aggregation of an organic suspension as a cationic flocculant for wastewater treatment and flocculation agent for dehydration of organic sludge. In particular, it exhibits excellent effects as a primary flocculation sludge in sewage treatment, activated sludge treatment of water-soluble organic matter, sludge generated in anaerobic treatment, and a flocculating agent for dehydration of these mixtures. The method of use is the same as that of a conventionally known cationic flocculant, for example, a quaternized polymer of dimethylaminoethyl methacrylate. That is, usually 0.1 ~
It is added and mixed in the range of 20 to 20000 ppm by weight to a suspension containing organic sludge in the form of a 0.5% by weight aqueous solution.

When the vinylamine copolymer of the present invention is used as a flocculant, it is a water-soluble polymer having a reduced viscosity value of 1 to 10 dl / g measured at 25 ° C. as a solution of 0.1 g / dl in 1N saline. Is preferred. Since the organic sludge coagulated using the vinylamine copolymer of the present invention forms stronger cohesive flocs than when a polymer obtained by modifying a homopolymer of N-vinylformamide is used, Vect Press By performing squeezing dehydration with a screw press, filter press, or mechanical dehydration such as centrifugal separation or vacuum filtration, the dehydration treatment speed is improved and the treatment amount is increased.
The water content of the dehydrated sludge decreases.

Further, the vinylamine copolymer of the present invention is also used as a cationic water-soluble polymer for the paper industry, and exhibits excellent effects as a drainage improver, a filler retention improver, and a paper strength enhancer. When used for these purposes, the value of the reduced viscosity measured at 25 ℃ as a solution of 0.1g / dl in 1N saline solution is
Water soluble polymers of 0.5 to 10 dl / g are preferred. As a method of using it, any conventionally known paper-making method can be used. That is, a cationic polymer corresponding to 0.05 to 2% by weight based on the dry weight of pulp is added to a pulp slurry of 1 to 3% by weight in the form of an aqueous solution of 0.1 to 5% by weight, and then papermaking is carried out. In the case of a paper strength enhancer, other than a method of making paper by adding it to a pulp slurry as an internal additive, a wet paper or,
The dried paper may be coated with a roll coater, a size press, and a dipping machine, and if necessary, a cationic starch, a sulfuric acid band and an anionic paper strengthening agent may be used in combination. In addition, regardless of the type of pulp, it is used for any of ground pulp, sulfide pulp, kraft pulp, beaten waste paper, and the like.

The vinylamine copolymer of the present invention is extremely stable even in the form of a dilute aqueous solution regardless of the quality of the dissolved water. Also,
It is stable even under weak alkaline papermaking conditions using calcium carbonate as a filler, does not lose its efficacy, is neutral, or
It is an additive that is excellent in weak alkaline papermaking conditions.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist.

[Production of vinylamine copolymer]

Example 1 8.76 g of N- (1,1-dimethyl-3-oxobutyl) acrylamide and 29.8 g of demineralized water were placed in a 200 ml four-necked flask equipped with a stirrer, a nitrogen introducing tube, and a cooling tube. 10% by weight after heating to 60 ° C with stirring in a nitrogen gas stream
0.2 g of 2,2'-azobis-2-amidinopropane dihydrochloride aqueous solution was added. The stirring was stopped and the mixture was kept at 50 ° C for 5 hours. 1 g of the obtained hydrous gel was dehydrated and precipitated in 20 ml of acetone, and the precipitate was vacuum dried to obtain a solid polymer. The residual monomer in acetone used for dehydration was analyzed by liquid chromatography to measure the polymerization rate.
The results are shown in Table 1.

The hydrogel of the obtained polymer was pulverized to a particle size of about 0.5 mm, and 10 g of the polymer was put together with 20 g of methanol into a reactor equipped with a 50 ml stirrer and a cooling tube. 2.6 g of 35 wt% hydrochloric acid was added with stirring, and the mixture was reacted for 4 to 6 hours while heating under reflux. The product was dehydrated with acetone and then vacuum dried. Reduced viscosity and modification rate (composition of modified product) of the obtained powdery water-soluble polymer (hereinafter referred to as polymer A)
Was measured by the method described below. The results are shown in Table 2.

(Measurement of Reduced Viscosity) A solid polymer was dissolved in 1N saline to a concentration of 0.1 g / dl, and the reduced viscosity at 25 ° C. was measured using an Ostwald viscometer.

Reduced viscosity [dl / g] = [(t-t ₀ ) / T ₀ ] /0.1 t ₀ : Fall time of saline solution t: Fall time of polymer solution (measurement of modification ratio) 0.1% solid polymer It was dissolved in distilled water at a concentration of wt%. 5.0 g of this aqueous solution was diluted to 200 ml with demineralized water,
After adjusting the pH of the solution to 3 using dilute hydrochloric acid, the modification ratio of the formyl group was determined from the equivalent amount of the obtained cation group by the colloid titration method using toluidine blue as an indicator using 1/400 normal potassium polyvinyl sulfate. It was calculated.

Examples 2 to 7 N- (1,1-dimethyl-3-oxobutyl) of Example 1
Instead of acrylamide, comonomers of the types and mole fractions shown in Table 1 were used, and after polymerization was carried out at the monomer concentrations shown in Table 1, the polymer was modified in the same manner as in Example 1 to give a water-soluble polymer. Got (Hereinafter, these are referred to as polymer B to
The polymerization rate (referred to as G) is shown in Table 1. Further, the results of measuring the reduced viscosity and the modification ratio (composition of the modified product) using the obtained water-soluble polymer in the same manner as in Example 1 are shown in Table 2.

[Coagulation Performance] Examples 8 to 14 and Comparative Examples 1 to 3 100 ml of mixed raw sludge (solid content 2.0% by weight) of A city sewage treatment plant
The mixture was placed in a 200 ml polyethylene beaker, and the polymers A to G produced in the above examples and the polymers H to H shown in Table 3 were used.
5 ml of J was added in the form of a 0.2% by weight aqueous solution. Diameter 5m at the tip
m Using a stir bar with 3 round bars of 20 mm length, 1000 rpm
The mixture was stirred at the speed of 10 seconds. The coagulated sludge was put into a cylinder having a 60-mesh nylon screen with a diameter of 65 mm at the bottom, and the sludge was filtered by gravity filtration, and the amount of filtrate after 10 seconds was measured. Furthermore, the sludge after gravity filtration was put into a centrifugal basket having a draining net at the bottom, and centrifugally dehydrated for 30 seconds at a rotation speed of 3000 rpm. The sludge after dehydration was dried at 110 ° C. for 6 hours to measure the solid content, and the water content of the sludge after centrifugal dehydration was calculated. The results are shown in Table 3.

[Paper Strength Increasing Effect] Examples 15 to 17 and Comparative Examples 4 to 5 A 1% slurry of LBKP having a freeness of 435 ml measured by the Canadian standard method was placed in a 500 ml beaker, and the polymer C, while stirring. E, G and I were added in the form of a 1% by weight aqueous solution in an amount of 0.4% by weight based on the dry weight of the pulp, and the mixture was kept for 1 minute. From this, a TAPPI standard square paper machine was used to make paper with a basis weight of 60 g.

For comparison, a similar paper was made without adding any polymer. The obtained wet paper was dried for 3 minutes using a 120 ° C. drum dryer. JIS-P8112 and JIS-P8112 after leaving the paper under the condition of 20 ℃ and 60% relative humidity
According to 8113, the specific rupture degree and the breaking length were measured.

Here, S ₁ : burst strength [kg / cm ² ] W: basis weight of test paper [g / m ² ] S ₂ : tensile strength [kg] B: width of test piece [mm] Shown in the table.

[Drainage Improving Effect] Examples 18 to 20 and Comparative Example 6 LBKP having a freeness of 220 ml measured by the Canadian standard method.
0.3% slurry 1 was placed in a 2 liter beaker, 0.2% by weight of the polymer C, E, G was added as an aqueous solution of 0.2% by weight to the dry weight of pulp while stirring, and the mixture was stirred at a rotation speed of 200 rpm for 1 hour.
After stirring for a minute, the freeness value was measured using a Canadian Freeness Tester. Further, for comparison, the same experiment was conducted without adding any polymer. The results are shown in Table 5.

EFFECTS OF THE INVENTION The novel hydrophobic high molecular weight polyvinylamine of the present invention largely contributes to the application fields of coagulants and papermaking additives.

Claims (2)

[Claims] 1. The following general formulas [I], [II] and [III]:
Consists of structural units represented by (In the formula, X represents an anion) (In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is 1 to 1 carbon atoms.
4 represents an alkyl group having 4 to 4 carbon atoms or an oxoalkyl group having 4 to 8 carbon atoms) The structural unit [I] has a mole fraction of 5 to 85 mol%, the structural unit [II] has a mole fraction of 5 to 85 mol%, and a structure The unit [III] has a molar fraction of 90 to 5 mol% and 0.1 g of 1N saline solution.
/ dl solution has a reduced viscosity of 0.1-10dl / g measured at 25 ℃
Is a vinylamine copolymer. 2. N-vinylformamide and a compound represented by the following general formula [IV]: (In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is 1 to 1 carbon atoms.
4 alkyl group or oxoalkyl group having 4 to 8 carbon atoms) in a molar ratio of 10:90 to 95: 5 is polymerized in the presence of a radical polymerization initiator, and the formyl group in the polymer is acidified. The following general formula [I], which is characterized in that
Consisting of structural units represented by [II] and [III], (In the formula, X represents an anion) (In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is 1 to 1 carbon atoms.
4 represents an alkyl group having 4 to 4 carbon atoms or an oxoalkyl group having 4 to 8 carbon atoms) The structural unit [I] has a mole fraction of 5 to 85 mol%, the structural unit [II] has a mole fraction of 5 to 85 mol%, and a structure The unit [III] has a molar fraction of 90 to 5 mol% and 0.1 g of 1N saline solution.
/ dl solution has a reduced viscosity of 0.1-10dl / g measured at 25 ℃
Is a method for producing a vinylamine copolymer.