JPH01236202A - Method for improving solubility of anionic high polymer and increasing viscosity of aqueous solution thereof - Google Patents

Abstract

PURPOSE:To increase the solubility of an anionic high polymer and the viscosity of its aqueous solution thereby improving the performance as, for example, flocculant, by dissolving an anionic high polymer in water which contains divalent or higher valent metal ions in the presence of sequestering agent(s). CONSTITUTION:0.001-5wt.% anionic high polymer which is an acrylamide polymer, a partial hydrolyzate thereof, a (co)polymer of acrylamide, (meth) acrylic acid or acrylamido-2-methylpropanesulfonic acid, or an alkali salt or an ammonium salt thereof is dissolved in water having a concentration of divalent or higher valent metal (e.g., Mg or Al) ions of 0.00001-10wt.% in the presence of one or more sequestering agents selected from the group consisting of succinic acid, maleic acid, ethylenediaminetetraacetic acid, etc., which can trap or fix water-soluble divalent or higher valent metal ions, in a concentration of 0.01-1,000 times as higher as the total concentration by weight of the divalent or higher valent metal ions in water, and the resulting solution is maintained at a pH in the range of 2-13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention improves the solubility of anionic polymers used in paper-making chemicals, flocculants for water treatment, etc. in existing hot water, and improves the solubility of the resulting aqueous solution. The present invention relates to a method for dissolving an anionic polymer that improves viscosity.

BACKGROUND OF THE INVENTION Anionic polymers are used in paper mills and water treatment fields by being dissolved in industrial water, river water, and the like. Anionic polymers have conventionally been dissolved in a dissolution tank by increasing the rotational speed of stirring or extending the dissolution time.

Problems that IJI is trying to solve Anionic polymers are currently widely used in the paper industry as adhesives, retention improvers, size fixing agents, etc., and as polymer flocculants in the water treatment field. There is.

These anionic high molecular weight polymers are used for the intended purpose after being dissolved to a gs degree of, for example, 0.01 to 0.5% by weight at the site of use. The dissolving water used to dissolve these anionic polymers may be city water, industrial water, underground water, river water, or the like.

However, the solubility of anionic polymers in current pumped water is not necessarily sufficient, and the resulting aqueous solution has a low viscosity, making it unsuitable for use as a viscosity agent for papermaking, such as other molecular flocculants, filtering agents, and retention improvers. etc., there were problems such as a decrease in cohesive force and an increase in the amount used.

Means for Solving the Problems The purpose of the present invention is to solve these problems, and as a result of research, it has been found that the main cause of this is metal ions with a valence of more than 2 that are contained in the existing hot water, and that anions When dissolving a high molecular weight polymer in water, dissolving it in the coexistence of a sequestering agent improves solubility, and when the dissolved water is a paper-making sticky agent, it exhibits sufficient viscosity and stringiness, The present invention was achieved by discovering that polymer flocculants and the like improve cohesive force.

That is, the present invention improves the water solubility and reduces the viscosity of the aqueous solution by dissolving the anionic polymer in water containing divalent or higher valence metal ions in the coexistence of a metal ion sequestering agent. The aim is to improve the properties of the polymer as a polymer flocculant, etc., compared to conventional products.

action The present invention will be further explained in detail below.

The anionic polymer of the present invention is one that is used or can be used in the above-mentioned paper-making sticky agents, polymer flocculants, drainage improvers, paper-making retention improvers, etc., and is completely soluble in ice.
It has water solubility including swelling and semi-solid state.

For example, typical examples include acrylamide polymers, partial hydrolysates of acrylamide, polymers or copolymers of acrylamide, acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid, or alkali salts or ammonium salts thereof. be. Further, the degree of anionization is preferably 3 mol% or more, more preferably 5 mol% or more.

Specific examples of the total bending ion M button agent in the present invention include phthalic acid, lactic acid, tartaric acid, gluconic acid, ascorbic acid, malic acid, glycolic acid, itaconic acid, succinic acid, maleic acid, citric acid, citraconic acid, and sulfuric acid. alkaline metal salts of acids, organic monobasic acids represented by malonic acid, glutamic acid, aspartic acid, etc., unsaturated acids, oxyacids, polyhydric oxyacids, nitrilotriacetic acid, catechol-3,5-disulfone Pond water Any material that is soluble and captures and fixes divalent or higher valent metal ions can be used.

It is effective to add the sequestering agent in an amount of 0.01 to 100 times, more preferably 0.1 to 10 times, the total weight of divalent or higher metal ions contained in water. Even if the amount added is increased beyond this point, the effect will be saturated.

When dissolving the anionic polymer, the pH of the dissolved water is maintained within the range of 2 to 13, preferably 5 to 9, and the concentration of divalent or higher metal ions contained in the water is 0.00001.
~10% by weight, preferably 0.0001-1.0% weight
The anionic polymer is added to water at a ratio of 0.0% to water.
001% to 5% by weight, preferably 0,01% by weight
The effects of the present invention can be fully exhibited by dissolving it within the range of 0.5%.

The anionic polymer is dissolved after adding the sequestering agent to water, or dissolved together with the sequestering agent. At this time, the effect of the present invention is fully exhibited by maintaining the temperature of the water within the range of 5°C to 80°C, preferably 10°C to 40°C.

Examples The insoluble matter contained in the anionic polymer used in the examples, stringiness, and dissolution viscosity were determined by the following method.

(1) Method for measuring insoluble matter contained in anionic polymer Anionic polymer is
'C) to a concentration of 0.1% by weight (1.5g), stirring blades (3 blades (diameter 50 layers) 2
Stir at a speed of 4QQrp- for 1 hour using a rod (attached to the tip of the rod and the 5c layer from there). next,
The obtained aqueous polymer solution was filtered through a 300 mesh sieve (JIS standard), dried at 125°C for 6 hours or more, and then weighed. The weight percentage of the insoluble matter remaining on the 300 taesb sieve after drying was determined, and this was defined as the insoluble matter (wt%).

(2) Stringability test of anionic polymer aqueous solution A glass rod (cylindrical type, 20 mmφ
, length 200mm), dip it 50mm from the tip, and
Pull out at a speed of cz/see. The time from when the glass rod was pulled out until the string of aqueous solution stretched between the tip of the rod and the liquid surface was broken was measured, and this time was defined as the stringing time.

(3) Viscosity measurement of anionic polymer aqueous solution The viscosity of the polymer aqueous solution was measured using a B-type viscometer (model B8L, manufactured by Tokyo Keiki Co., Ltd.). Here, the temperature of the aqueous solution was set to 25° C., and the rotor of the viscometer was set to 3 Orpm using a No. 2 rotor.

Example 1 Magnesium chloride, calcium chloride, cobalt chloride, zinc chloride and barium chloride were added to distilled water so that each metal ion concentration was 3Qppm, and dissolved, followed by sequestering agent A (disodium ethylenediaminetetraacetate). 300 each of metal ion sequestering agent B (maleic acid), metal ion sequestering agent C (phthall!At)
The pH was adjusted to 7.0 with 0.2N aqueous sodium hydroxide solution.

Next, add anionic copolymer A to 1500 g of this aqueous solution.
(Composition Niacrylamide/Sodium acrylate = 8
5+ol/15+o1 Molecular weight: 20X 106 (Formula [y) of Japanese Patent Publication No. 40-20195] ] = 3.73X10
-'Mw, 30°C a/g, calculated from IN NaNO3)) was added and dissolved based on the method described in the method for measuring insoluble content.

The insoluble matter, stringing time and viscosity of this aqueous solution were measured and shown in Table 1, and compared with the case where no sequestering agent was added.

The method for improving the solubility of anionic copolymer A in the coexistence of a sequestering agent recognized in the present invention is that stable complexes of various divalent metal ions and a sequestering agent improve the solubility of anionic copolymer A. It is clear that the polymer solution is improved and has an excellent effect of suppressing stringiness and viscosity reduction of an aqueous polymer solution.

Table 1 Example 2 In the same manner as in Example 1, aluminum chloride and ferric chloride were added to distilled water so that the metal ion moisture content was 30 ppm, dissolved, and then sequestering agents A, B, C
was added to give a concentration of 300ppffi, and 0.2N
The pH was adjusted to 7.0 with an aqueous sodium hydroxide solution. Next, 1.5 g of anionic copolymer A was added to 1500 g of this aqueous solution, and after dissolving, the undissolved content, stringing time, and viscosity of the aqueous solution were measured. Display the measured values.
2 and compared with the case where no sequestering agent was added.

Trivalent metal ions make the anionic copolymer insoluble in water. The present invention also exhibits excellent effects when dissolving trivalent metal ions in water.

Example 3 Water used in a certain paper factory (Table of main ion compositions)
Sequestering agent A was added to 50 ppm (shown in 3) and dissolved, and the pH was adjusted to 7.0 with a 0.2N aqueous sodium hydroxide solution. Next, 1.5 g of anionic copolymer A was added to 1500 g of this aqueous solution and dissolved in the same manner as in Example 1. The insoluble matter, stringing time and viscosity of this aqueous solution are shown in Table 4 and compared with the case where no sequestering agent was added.

The present invention also showed a very significant improvement effect on paper mill wastewater containing mixed divalent and trivalent metal ions.

Example 4 The results of measuring the change in insoluble matter over time in Example 3 are shown in Table 5, and compared with the case where no sequestering agent was added. The dissolution tank used in the measurement had a volume of about 5 m'', and the heptanionic copolymer A was dissolved therein to a concentration of 0.1% by weight using a stirring blade (two-blade spacing type).

The anionic copolymer A can be completely dissolved in a short time by adding sequestering agent A to water in a dissolution tank at a certain paper mill, and the resulting aqueous solution has sufficient stringiness as a sticky agent. and viscosity.

Example 5 A kaolin suspension was used as a model wastewater, and anionic copolymer B (composition: Niacrylamide/sodium acrylate = 95 x 115 mol, molecular weight: 18 x 10
6 (Formula of Special Publication 1972-20185 [ηConi 3.F 3X,
0-a i, 0.66.30℃a/g, IN-Na
A flocculation test was conducted using NO3.

Kaolin suspension (0.5% by weight) was added with liquid sulfuric acid band (A
Q203: After adding 8.0% by weight 6) to 1100pp, adjust the pH with 0.2N-NaOH aqueous solution.
was adjusted to 6.5. Sequestering agent A in Yokohama city water
Anionic copolymer B was added at a concentration of 0.0 ppm each to an aqueous solution whose pH was adjusted to 7.0.
It was dissolved in the same manner as in Example 1 so that the concentration was 1π9%.

The agglutination test was carried out using a jar tester, and the metal ion M
A polymer aqueous solution without the coexistence of a sedative was compared with Seiichi. The test results are shown in Table-6. Here, the transmittance is the integrating sphere light'1
i scattering photometer (manufactured by Tokyo Shinshoku Co., Ltd., M()DL F28)
It was determined by 00).

It is clear that when the anionic conjugate B is dissolved in the coexistence of a sequestering agent, the resulting aqueous solution has a good flocculating effect on the kaolin suspension.

(Leaving space below) Table-2 Table-3 Table-4 Table-6 Effects of the invention The method of the present invention suppresses the decrease in viscosity of an anionic polymer aqueous solution due to total bending ions, and It has an excellent effect of improving solubility and is industrially useful.

Claims (7)

[Claims] (1) When dissolving anionic polymers in water containing divalent or higher metal ions, by dissolving them in the coexistence of a sequestering agent, the solubility is improved and the viscosity of the aqueous solution is improved. Method. (2) The anionic polymer is an acrylamide polymer, a partial hydrolyzate of acrylamide, or acrylamide, acrylic acid, methacrylic acid, acrylamide-2-
The method according to claim 1, which is a polymer or copolymer of methylpropanesulfonic acid or an alkali salt or ammonium salt thereof. (3) The method according to claim 1, wherein the metal ion sequestering agent is water-soluble and is selected from those that capture and fix divalent or higher metal ions. (4) Add a sequestering agent to a concentration of 0.01 to 1000 times the total weight concentration of divalent or higher metal ions contained in water.
The method according to claim 1, characterized in that they are allowed to coexist at twice the weight concentration. (5) The method according to claim 1, characterized in that the pH of the dissolved water during dissolving the anionic high molecular weight polymer is maintained within the range of 2 to 13. (6) The concentration of divalent or higher metal ions contained in water is 0.
．． The method according to claim 1, characterized in that the anionic high molecular weight polymer is dissolved in the range of 0.001% to 5% by weight in the water of 0.0001% to 10% by weight. (7) The sequestering agent is phthalic acid, lactic acid, tartaric acid, gluconic acid, ascorbic acid, malic acid, glycolic acid, itaconic acid, succinic acid, maleic acid, cunic acid, citraconic acid, oxalic acid, malonic acid, glutamic acid. , organic monobasic acids and dibasic acids represented by aspartic acid, etc.
One or more selected from unsaturated acids, oxyacids, alkali metal salts of polyhydric oxyacids, nitrilotriacetic acid, catechol-3,5-disulfonic acid, ethylenediaminetetraacetic acid, N-oxyethylethylenediaminetriacetic acid, sulfosalicylic acid, etc. Claim 3 is characterized in that it captures and fixes two or more kinds of compounds, or alkali metal salts of these compounds, or water-soluble metal ions with a valence of two or more. the method of.