JP2602724B2 - Acrylamide copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention [Industrial Application Field] The present invention relates to a water-soluble acrylamide polymer having improved spinnability, and a papermaking adhesive and a coagulation dehydrating agent comprising the polymer. It is about.

A water-soluble acrylamide polymer having a high degree of polymerization and giving a high viscosity aqueous solution when dissolved in water, due to its properties,
It is widely used as a coagulation dewatering agent, a papermaking adhesive, a soil conditioner, a thickener, an oil recovery agent, and the like, and is widely used in many industrial fields.

The acrylamide copolymer of the present invention is an improved version of the conventional water-soluble acrylamide polymer, and is used in the above-mentioned field in the same manner as those polymers, and is particularly excellent as a papermaking adhesive and a coagulating dehydrating agent. To have an effect,
It can be more widely used in the papermaking and wastewater treatment industries.

[Prior Art] It is known that the performance of a water-soluble acrylamide polymer having a high degree of polymerization as a papermaking adhesive is closely related to the spinnability in an aqueous solution. As described in 27808, as a method for improving the spinnability of the acrylamide polymer aqueous solution, a conventionally proposed method is a method of copolymerizing 2-acrylamido-2-methylpropanesulfonic acid salt ( JP-A-52-3758
0), a method using an azo compound as a polymerization initiator in the presence of a heavy metal salt and / or a reducing inorganic phosphorus compound (JP-A-57-121007). The illustrated example shows that these proposed methods employ increasing the viscosity of the aqueous acrylamide polymer solution as a technical solution to improve spinnability. .

Acrylamide polymers having a high degree of polymerization have also been awarded as flocculants. Among them, as an acrylamide polymer containing ammonium acrylate, a method of polymerizing as an aqueous solution of 0.1% ammonium hydroxide at pH 10.7 for the purpose of obtaining a polymer having a high molecular weight has been reported (Japanese Patent Application Laid-Open No. 48-48). 31281).

Also, an aqueous solution copolymer of acrylic acid and an alkali or ammonium salt of acrylic acid or a mixture thereof (Japanese Patent Application Laid-Open No.
55-40749) and a method for producing a swellable substance obtained by polymerizing a solution obtained by adding alkali or ammonium, or both, and water to acrylic acid without using a crosslinking agent (JP-A-55-58208). ).

However, these are polymerized with ammonium acrylate alone or in combination, but the spinnability has not been sufficiently improved, and there are polymers with extremely long spinnability. It does not always have excellent performance as an agent.

[Problems to be Solved by the Invention] In general, an aqueous solution of a water-soluble polymer having a high degree of polymerization shows a high viscosity, but a polymer having a high degree of polymerization tends to form a gel insoluble in water. When the combined aqueous solution is used industrially, clogging of the piping and pump of the apparatus occurs, and when it is used as a papermaking adhesive, it often causes various problems such as soiling a papermaking blanket.

In the method using 2-acrylamido-2-methylpropanesulfonate, an expensive compound must be used in an amount of 6 to 8% by weight as an optimum copolymerization amount. It is not necessarily suitable as a method for producing.

The present inventors have found that, in order to obtain a water-soluble acrylamide polymer whose aqueous solution exhibits high spinnability, the solubility in water is excellent without substantially increasing the degree of polymerization, that is, the viscosity of the aqueous solution, and inexpensive. Intensive investigations were made on the method that can be manufactured.

(B) Configuration of the Invention [Means for Solving the Problems] The present inventors have diligently studied means for solving the above-mentioned problems, and the above-mentioned problems have been solved by two types of acrylics comprising ammonium acrylate and other acrylates. The present inventors have found that the problem is solved by copolymerizing an acid salt with acrylamide to form an acrylamide copolymer, and completed the present invention.

That is, the present invention has the following repeating unit, and is 1% as measured with a B-type viscometer (rotation speed 12 rpm: rotor 3: temperature 25 ° C.).
The present invention relates to an acrylamide copolymer characterized by having an aqueous solution having a viscosity of 500 cps or more, and a papermaking adhesive and a coagulating dehydrating agent comprising the copolymer.

ApBqCr where A is acrylamide or a monomer unit containing acrylamide as a main component, B is an ammonium acrylate unit, C is an acrylate unit other than ammonium acrylate, p is 70 to 95 mol%, and q + r is 5 to 30mol% (p
+ Q + r = 100), and q: r (molar ratio) indicates 2 to 60:98 to 40.

○ Acrylate The acrylamide copolymer of the present invention is obtained by copolymerizing two kinds of acrylates composed of ammonium acrylate and other acrylates with acrylamide,
As acrylates other than ammonium acrylate,
Examples thereof include alkali metal salts such as sodium and potassium, and alkaline earth metal salts such as magnesium. In the present invention, alkali metal salts are preferable. That is, acrylamide /
Ammonium acrylate / alkali metal acrylate copolymers are preferred for the present invention.

Among the copolymers having the above-mentioned constitution, the proportion of the monomer is 5 to 30 mol%, preferably 10 to 30 mol%, more preferably 15 to 27 mol%. Water-soluble acrylamide copolymer obtained by polymerizing the monomer, wherein ammonium acrylate is 2 to 6 mol%, preferably 5 to 40 mol% of the total amount of the acrylate.
l%, more preferably 10 to 35 mol%.

The acrylamide copolymer of the present invention having the above constitution has improved solubility and spinnability without increasing its aqueous solution viscosity.

That is, the acrylamide copolymer produced using two kinds of acrylates (one of them is ammonium acrylate) is compared with a conventionally known polymer obtained by polymerizing sodium acrylate and acrylamide. Thus, the viscosity of the aqueous solution is equivalent to that of the polymer to which ammonium acrylate is not added, but the spinning property of the aqueous solution is very excellent.

When the acrylamide copolymer of the present invention is used as a papermaking adhesive, a good paper layer is formed without a wash-off phenomenon, and the paper does not tend to adhere to the dryer surface and does not cause paper breakage. It can be used as a papermaking adhesive.

When the acrylamide copolymer of the present invention was used as a coagulation dehydrating agent, it was found that the coagulation sedimentation property was excellent particularly in a coagulation sedimentation test of papermaking wastewater.

As a conventional finding, there is a report that a copolymer of 2-acrylamide-2-methylpropanesulfonate and acrylamide is excellent as a flocculant, and that the longer the spinnability, the faster the flocculation and sedimentation speed (Japanese Patent Laid-Open No. 2000-163,837). Showa 52-3758
0).

In the present invention, a coagulated dehydrating agent having the same performance is obtained by using inexpensive ammonium acrylate.

Incidentally, the copolymer obtained by polymerizing a monomer having an amount of acrylate in the monomer of less than 5 mol% has a small degree of the above effects, and is obtained by polymerizing a monomer having an amount of more than 30 mol%. The copolymer obtained has improved spinnability but is accompanied by an increase in viscosity.
When the amount of ammonium acrylate is less than 2 mol% with respect to the total amount of the acrylate, the effect of improving spinnability is small, and when it exceeds 60 mol%, the spinnability and solubility are reduced.

Further, as the acrylamide copolymer of the present invention, a copolymer having an absolute value of a colloid equivalent value in the range of 0.7 to 4.5 meq / g is preferable, more preferably in the range of 1.3 to 3.9 meq / g, and particularly preferably 2.0. It is in the range of 3.5 meq / g.

Further, the acrylamide copolymer of the present invention, utilizing the property that it can be a high-viscosity aqueous solution, as a coagulation dewatering agent, a papermaking adhesive, a soil conditioner, a thickener, a petroleum recovery agent, etc.
In particular, it is an improved acrylamide polymer used as a papermaking adhesive and coagulation dehydrating agent. Is a B-type viscometer (rotation speed 12
The viscosity of a 1% aqueous solution measured with a rotor (rpm: rotor 3: temperature 25 ° C.) must be 500 cps or more, more preferably 3000 cps or more.

A higher viscosity is desirable, but the upper limit is naturally determined in view of the possibility or ease of production.

○ Other monomers As far as the acrylamide copolymer of the present invention does not degrade the properties of the polymer, if necessary, for example, an alkali metal salt such as a sodium salt of styrene sulfonic acid or an ammonium salt, a sulfoethyl acrylate, etc. Alkali metal salts or ammonium salts such as sodium salts of sulfoalkyl (meth) acrylates, N-alkylacrylamides such as vinyl acetate and N, N-dimethylacrylamide, acrylates such as methyl acrylate, methyl methacrylate and the like. A copolymer obtained by further copolymerizing one or more monomers selected from water-soluble or water-insoluble monomers such as methacrylic acid esters and methoxyethyl acrylate can also be used.

O Production method The acrylamide copolymer of the present invention can be produced by a known method.

For example, known polymerization methods such as aqueous solution polymerization, reversed-phase emulsion polymerization, and reversed-phase suspension polymerization can be employed for the polymerization. However, when the product price is taken into consideration, the aqueous solution polymerization method is preferable, and if the product price is ignored, known polymerization methods such as reverse-phase emulsion polymerization and reverse-phase suspension polymerization can be employed.

The aqueous solution polymerization preferably reduces the concentration of the monomer in the aqueous solution.
15% by weight or more, more preferably 17 to 40% by weight, known polymerization catalysts such as azo-based catalysts such as azobisamidinopropane hydrochloride and azobiscyanovaleric acid, and peroxide-based catalysts such as persulfate, Using an azo catalyst or a peroxide catalyst together with a reducing agent such as a sulfite, the polymerization initiation temperature is 0 to
Usually performed at 25 ° C. The amount of the catalyst used is generally 100 to 6000 ppm for the azo system, 1 to 200 ppm for the peroxide system, and about 1 to 200 ppm of the reducing agent used in combination with the monomer.

If necessary, a chain transfer agent such as alcohol amine, mercaptan, amine, urea and its derivatives, sodium sulfate, sodium chloride, polyethylene glycol, and a surfactant may be used to polymerize substances required in the conventional method. And polymerized.

Generally, in the case of aqueous polymerization, the acrylamide component partially hydrolyzes to reach a peak temperature of 75 to 95 ° C.,
Converted to anionic units. Therefore, the colloid equivalent value of the obtained polymer is about 0.2 to 0.8 meq / g higher than the colloid equivalent value expected from the charged composition. Therefore,
At the time of charging, the composition of the acrylate must be set lower than the monomer composition that can obtain the target colloid equivalent value. Further, since the monomer is converted as described above, the constituent ratio of the monomer constituting the copolymer in the present invention is:
Based on the amount at the time of preparation.

According to the aqueous solution polymerization, it is obtained from a rubber-like elastic body containing a large amount of water, and after this is minced into a minced meat shape using a known method, for example, using a chopper, a 50- The powder is dried to a solid content of 85% or more with hot air at 120 ° C., and further pulverized by a known pulverizer such as a roll-type pulverizer into a powder of 15 mesh or less.

Prior to the drying step, a method of drying after previously dehydrating with an alcohol such as methanol or ethanol or with acetone may be employed.

○ Usage method When the acrylamide copolymer of the present invention is used as a papermaking adhesive, it is usually 0.03 to 0.5%
Preferably, it is dissolved in a concentration of 0.05 to 0.2%, and is diluted 2 to 10 times as needed before use and supplied to a stage before the paper making process, for example, a round vat. The addition amount is usually 0.01 to 2% by weight based on the stock.

The papermaking adhesive of the present invention can also be used by mixing with known adhesives such as polyethylene oxide and Asahi. In addition, a known method can be employed for paper-making the size paper. Further, it is also possible to use a known internal and external dryer release agent for improving the releasability from the dryer.

As the paper machine, a known paper machine such as a round paper machine, a short net paper machine, a fourdrinier paper machine, and a former type paper machine can be applied. In general, toilet paper, chili paper,
In the case of making household paper such as tissue paper, a Yankee dryer is used, but the invention can also be applied to a paper machine provided with a multi-cylinder dryer.

When the acrylamide copolymer of the present invention is used as a coagulation dehydrating agent, it can be used alone as a wastewater treatment in papermaking, mining, civil engineering, metal, and other various production processes, like a general anionic coagulant. It can also be applied to sewage and night soil as a combined cation / anion system and tertiary treatment.

It has been found that the acrylamide copolymer of the present invention exhibits excellent performance in coagulating sedimentation of wastewater for papermaking due to its particularly long spinnability.

[Action] By copolymerizing two kinds of acrylates composed of ammonium acrylate and other acrylates with acrylamide, the acrylamide polymer has excellent spinnability and solubility that the polymer does not have. The effect is that it can be applied without changing the viscosity of the aqueous solution.

[Example] Hereinafter, an example will be described together with a comparative example.

Comparative Example 1 A stainless steel dewar bin was charged with 1 kg of an aqueous solution of acrylamide and sodium acrylate having a composition of 83 mol%: 17 mol% and a monomer concentration of 25%. 15 ℃ of aqueous solution temperature
Then, nitrogen was introduced and degassed for 90 minutes. Azobisamidinopropane hydrochloride was added as a catalyst in an amount of 4000 ppm based on the total amount of the monomers. The polymerization was completed 110 minutes after the start of the temperature rise. The obtained gel was taken out, processed into ground meat with a small chopper, and dried in a hot air dryer at 80 ° C. for 3 hours. The obtained solid is crushed, and the viscosity of the aqueous solution,
When the colloid equivalent value, spinnability and the amount of insoluble matter were measured, the viscosity was 5650 cps, the colloid equivalent value was −3.05 meq / g, the spinnability was 125 mm, and the amount of insoluble matter was 1 ml or less.

In addition, the measurement of the viscosity, the spinnability and the amount of insoluble matter was performed as follows.

▽ 1% viscosity measurement Dilute 4 g of powder with 400 ml of distilled water, stir for 3 hours,
The temperature was adjusted to 5 ° C and the number of rotation was 12 rpm with a B-type viscometer, rotor
Was measured under the following conditions.

▽ Spinnability 2 g of powder was diluted with 400 ml of distilled water and stirred for 3 hours.
Adjust the temperature to 5 ° C, set the vessel on a table that descends at a speed of 5 mm / sec, and immerse a glass ball with a diameter of 10 mm fixed to the support base to a position of about 20 mm in depth. 5mm / se
The solution was lowered at the speed of c and the solution was drawn in a thread form. The time T (sec) from the time when the lower end of the glass ball reached the surface of the solution to the time when the thread was cut was measured, and the spinnability was calculated by the following equation.

Spinnability (mm) = 5 × T 量 Insolubles 0.5 g of powder was diluted with 500 ml of distilled water, stirred for 3 hours, filtered with a 20-cm diameter 83-mesh sieve, washed with water, and washed on a sieve. The remaining insoluble matter was collected, taken into a cylinder, and the volume was measured.

Examples 1 to 12 and Comparative Example 2 Polymerization was carried out in the same manner as in Comparative Example 1 except that the charged composition was changed. The obtained results are summarized in Table 1 including the results of Comparative Example 1.

Comparative Example 3, Examples 13 to 14 Polymerization was carried out in the same manner as in Comparative Example 1, except that the charged composition, the catalyst and the adjustment temperature were changed. The catalyst was 2000 ppm sodium azobiscyanovalerate and 3 ppm ammonium persulfate.
5 ppm was used. The conditioning temperature is 10 ° C. Table 2 summarizes the obtained results.

Comparative Example 4 Polymerization was carried out in the same manner as in Comparative Example 1 except that the monomer concentration, the charged composition and the catalyst were changed. The monomer concentration was adjusted to 27.5% by weight. As the catalyst, 2000 ppm of sodium azobiscyanovalerate and 300 ppm of ammonium persulfate were used. Table 2 summarizes the obtained results.

Use Comparative Example 1, Use Examples 1 to 5 Using the polymers obtained in the above Comparative Examples and Examples, for the performance as a papermaking adhesive, the free water amount was determined using a Canadian standard freeness meter. The degree of effect was confirmed by calculating the freeness of freeness described in 163524 and the like. The experiment was carried out using 545 ml of Canadian standard freeness (JIS-P8121), 0.3 wt% of the beaten NBKP pulp slurry, and 0.1 wt% of the above polymer aqueous solution at a polymer weight of 0.05 wt% based on the amount of pulp in the slurry.
%, 0.15%, and 0.30%, and the filtrate (V) at this time was measured with a Canadian standard freeness meter. The freeness was calculated by the following equation.

The higher the freeness, the greater the effect as a papermaking adhesive. Table 3 summarizes the obtained results.

Use Comparative Examples 2 to 4, Use Examples 6 to 8 Using the polymers obtained in the above Comparative Examples and Examples, the performance as a coagulated dehydrating agent was tested for the following adjusted wastewater.

As a regulated wastewater, a predetermined amount of a sulfuric acid band was added to 500 ml of pulp wastewater (COD 380 ppm: pH 3.70), and the mixture was stirred.
I got it. To this conditioned wastewater, a predetermined amount of a 0.1% aqueous solution of the polymers of Comparative Examples and Examples in Tables 1 and 2 is added. Stir at 120 rpm for 1 minute with a jar tester to generate floc. The mixture is further stirred at 50 rpm, and the resulting floc diameter is observed. After completion of the stirring, the time required for the floc to sink 5 cm from the water surface is measured, and the sedimentation speed is determined. After standing for 30 minutes, the COD of the supernatant water is measured. Table 4 summarizes the obtained results.

It can be seen that the copolymer of ammonium acrylate, sodium acrylate and acrylamide has an excellent effect on the settling time, the clarity of the filtrate and the reduction of COD in the coagulation sedimentation of the conditioned wastewater.

(C) Effects of the Invention According to the present invention, an acrylamide polymer having high spinnability can be produced at a low cost, and is widely used as an agent in various fields such as a soil improver as well as a papermaking adhesive and a coagulating dehydrating agent. Use is expected.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-30505 (JP, A) JP-A-2-209906 (JP, A) JP-A-2-104796 (JP, A) JP-A-63-30 183907 (JP, A) JP-A-62-89714 (JP, A) JP-A-60-161410 (JP, A)

Claims (3)

(57) [Claims] 1. Acrylamide copolymer having the following repeating unit, wherein the viscosity of a 1% aqueous solution measured by a B-type viscometer (rotation speed 12 rpm: rotor 3: temperature 25 ° C.) is 500 cps or more. Coalescing. ApBqCr where A is acrylamide or a monomer unit containing acrylamide as a main component, B is an ammonium acrylate unit, C is an acrylate unit other than ammonium acrylate, p is 70 to 95 mol%, and q + r is 5 to 30mol% (p
+ Q + r = 100), and q: r (molar ratio) indicates 2 to 60:98 to 40. 2. A papermaking adhesive comprising the acrylamide copolymer according to claim 1. 3. A coagulated dehydrating agent comprising the acrylamide copolymer according to claim 1.