Anionic water-in-water papermaking aid and method of making and using same

Abstract

This invention discloses an anionic water-in-water papermaking additive, its preparation method, and its application, belonging to the field of polymer preparation. Deionized water, anionic monomer b, and a functional monomer are added to a reaction vessel, and oxygen is removed for 15-30 minutes. When the reaction vessel temperature reaches 40-50°C, initiator b is added. After the reaction reaches 60-90°C, it is maintained at the current temperature for 2-5 hours to mature, yielding an anionic dispersant. The anionic dispersant synthesized by this invention using anionic monomers and functional monomers has a viscosity-average molecular weight of 200,000-500,000. It can form multiple hydrogen bonds, effectively stabilizing the precipitated anionic polymer in the anionic water-in-water system. Furthermore, because it can form multiple hydrogen bonds, it can also form multiple hydrogen bonds with fibers in papermaking, increasing paper strength.

Description

Technical Field

[0001] This invention belongs to the field of polymer preparation, and in particular to an anionic water-in-water papermaking additive, its preparation method and application. Background Technology

[0002] Water-in-oil emulsions contain mineral oil, resulting in higher costs. Furthermore, the oil entering the pulp causes secondary pollution and may affect paper quality. Water-in-water emulsions, on the other hand, combine the advantages of water-in-oil emulsions. Because production involves dispersion and polymerization in an aqueous phase, they are lower in cost, pollution-free, and do not affect paper quality. However, water-in-water emulsions contain dispersants and salt dispersion media, which can lead to some waste. Therefore, it is necessary to develop water-in-water papermaking additives with high utilization rates. Summary of the Invention

[0003] To overcome the above-mentioned technical defects, the present invention provides an anionic water-in-water papermaking additive, its preparation method and application, so as to solve the problems involved in the background art.

[0004] In a first aspect, the present invention provides a method for preparing an anionic water-in-water papermaking additive, comprising: Add deionized water, anionic monomer b, and functional monomer to the reactor, deoxygenate for 15-30 minutes, and when the reactor temperature reaches 40-50℃, add initiator b to the reactor; when the reaction reaches 60-90℃, maintain the current temperature for 2-5 hours to obtain anionic dispersant. The functional monomer has any of the following structural formulas: , , ; Where R1 is -CH2, -CH2-CH3, –CH2-CH2-CH3; R2 is -CH-, –CH2-CH-, –CH2-CH2-CH-; R3 is -CH2, –CH2-CH3, –CH2-CH2-CH3; R4 is -CH2, –CH2-CH3, –CH2-CH2-CH3; Deionized water, the anionic dispersant, the metal ion chelating agent, acrylamide, inorganic salt, and anionic monomer a are sequentially added to the reaction vessel and stirred to dissolve. The pH of the entire system is adjusted to 6-8 using an alkaline substance, and nitrogen is blown for 20-30 minutes. When the temperature of the reactor reaches 20-40°C, add the initiator intermittently to the reactor, wait for the reaction to rise to 50-80°C, and maintain the current temperature for 1-3 hours to mature. Once the curing process is complete, the temperature is lowered, a post-treatment agent is added, the mixture is stirred evenly, filtered, and discharged to obtain the anionic water-in-water papermaking additive.

[0005] Preferably or optionally, the anionic monomer b is one or more of acrylic acid, itaconic acid, 2-acrylamide-2-methylpropanesulfonic acid, maleic acid, and methacrylic acidsulfonic acid; The mass ratio of the anionic monomer b to the functional monomer is 3:1 to 6:1.

[0006] Preferably or optionally, the initiator b is one or more of sodium persulfate, potassium persulfate, and ammonium persulfate; The amount of initiator b is 0.1%-0.4% of the total mass of anionic monomer b and functional monomer.

[0007] Preferably or optionally, the viscosity-average molecular weight of the anionic dispersant is 200,000 to 500,000.

[0008] Preferably or optionally, the amount of the anionic dispersant accounts for 1% to 5% of the total weight of the entire reaction system.

[0009] Preferably or optionally, the metal ion chelating agent is one or more selected from sodium citrate, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium gluconate, and sodium tripolyphosphate; the amount of the metal ion chelating agent is 0.01% to 0.05% of the total weight of the entire reaction system; The inorganic salt is aluminum sulfate; the amount of the inorganic salt used accounts for 20% to 28% of the total weight of the entire reaction system. The anionic monomer a is one or more of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and methacrylic acid; the molar ratio of acrylamide to anionic monomer a is 4 to 7, and the total mass of anionic monomer a and acrylamide accounts for 15 to 20% of the total weight of the entire reaction system.

[0010] Preferably or optionally, the alkaline substance is one of sodium hydroxide, potassium hydroxide, or ammonia water; The initiator is a redox initiator, wherein the oxidant is one of sodium persulfate, ammonium persulfate, and potassium persulfate, and the reducing agent is sodium bisulfite and / or sodium metabisulfite; wherein the redox initiator is added intermittently and alternately, the mass ratio of the redox initiator is 0.5 to 1, and the amount of redox initiator accounts for 0.05% to 0.1% of the total weight of the entire reaction system; The post-treatment agent is one or more of citric acid, ammonium sulfate, and adipic acid amine, and the amount of the post-treatment agent accounts for 2.5% to 6.25% of the total weight of the entire reaction system.

[0011] The present invention also provides a method for preparing an anionic water-in-water papermaking additive based on the above-mentioned anionic water-in-water papermaking additive, wherein the viscosity-average molecular weight of polyacrylamide in the papermaking additive is 8 million to 12 million.

[0012] The present invention also provides an application of the aforementioned anionic water-in-water papermaking additive as a papermaking dry strength agent and / or retention and filtration aid.

[0013] This invention relates to an anionic water-in-water papermaking additive, its preparation method, and its application. Compared with the prior art, it has the following advantages: 1. The present invention utilizes anionic monomers and functional monomers to synthesize anionic dispersants with a viscosity-average molecular weight of 200,000-500,000. It can form multiple hydrogen bonds and can effectively stabilize the precipitated anionic polymers in anionic water-in-water systems. In addition, because it can form multiple hydrogen bonds, it can also form multiple hydrogen bonds with fibers in papermaking, thereby increasing the strength of paper.

[0014] 2. In the anionic water-in-water papermaking additive of the present invention, aluminum sulfate is used as a dispersion medium. Aluminum sulfate can compress polymer molecular chains in the system and use its solubility to cause the polymer to precipitate in the system. Thus, aluminum sulfate can not only play a role in the application of papermaking retention and filtration aids, but also play a flocculation role. Therefore, aluminum sulfate can be fully utilized in the system.

[0015] 3. In the application of papermaking, the anionic water-in-water papermaking additive of the present invention can play the role of flocculation, retention and filtration aid and efficient flocculation with its macromolecular polymer, and the role of low molecular weight dispersant as papermaking dry strength agent. In the system, aluminum sulfate can be used as both a dispersion medium and an inorganic flocculant. Therefore, the anionic water-in-water papermaking additive can replace a variety of papermaking additives. Moreover, it is simple to prepare, low in cost, and is a highly utilized environmentally friendly papermaking additive. Detailed Implementation

[0016] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0017] The present invention will be further described below with reference to the embodiments. The examples described are intended to explain the present invention and should not be construed as limiting the present invention.

[0018] Example 1: A method for preparing an anionic water-in-water papermaking additive includes the following steps: Step 1: Add 500g of deionized water to the reactor, along with 200g of acrylic acid and N-vinylmorpholine in a mass ratio of 3:1. After deoxygenation for 30 minutes, when the reactor temperature reaches 45℃, add 0.1% sodium persulfate initiator (based on the total mass of acrylic acid and N-vinylmorpholine). When the reaction reaches a maximum temperature of 65℃, maintain the maximum temperature at 65℃ for 3 hours to obtain anionic dispersant A1.

[0019] Step 2: Add 48.89% deionized water, 3% anionic dispersant A1, 0.03% disodium ethylenediaminetetraacetate, 15% acrylamide, 25% aluminum sulfate, and 3% acrylic acid by weight to the reaction vessel in sequence and stir to dissolve. Adjust the pH of the entire system to 7.2 with ammonia and purge with nitrogen for 30 minutes.

[0020] Step 3: When the temperature of the reactor reaches 25°C, add 0.01% sodium persulfate initiator by weight to the reactor and stir well. Then add 0.01% sodium metabisulfite initiator by weight. Wait for the reaction to slow down, and then add 0.01% sodium persulfate initiator and 0.01% sodium metabisulfite initiator by weight. Repeat this process intermittently (4 times in total) until the reaction reaches the highest temperature of 60°C. Maintain the reaction at the highest temperature of 60°C for 3 hours.

[0021] Step 4: When the curing is complete, cool down, add 5% ammonium sulfate by weight, stir evenly, filter, and discharge to obtain anionic water-in-water green cleaning papermaking additive B1.

[0022] Example 2: A method for preparing an anionic water-in-water papermaking additive includes the following steps: Step 1: Add 500g of deionized water to the reactor, along with 200g of a total of 2-acrylamide-2-methylpropanesulfonic acid and N-vinylmorpholine, wherein the mass ratio of 2-acrylamide-2-methylpropanesulfonic acid to N-vinylmorpholine is 3:1. After deoxygenation for 30 minutes, when the reactor temperature reaches 50℃, add 0.4% sodium persulfate initiator (based on the total mass of 2-acrylamide-2-methylpropanesulfonic acid and N-vinylmorpholine). When the reaction reaches a maximum temperature of 65℃, maintain the maximum temperature at 65℃ for 3 hours to obtain anionic dispersant A2.

[0023] Step 2: Add 47.37% deionized water, 3% anionic dispersant A2, 0.05% disodium ethylenediaminetetraacetate, 16% acrylamide, 28% aluminum sulfate, and 3% acrylic acid by weight into the reaction vessel and stir to dissolve. Adjust the pH of the entire system to 7.23 with ammonia and purge with nitrogen for 30 minutes.

[0024] Step 3: When the temperature of the reactor reaches 40℃, add 0.01% sodium persulfate initiator by weight to the reactor and stir evenly. Then add 0.01% sodium metabisulfite initiator by weight. Wait for the reaction to slow down, and continue to add 0.01% sodium persulfate initiator and 0.01% sodium metabisulfite initiator by weight. Repeat this process intermittently (a total of 4 times) until the reaction reaches the highest temperature of 60℃. Maintain the reaction at the highest temperature of 60℃ for 3 hours.

[0025] Step 4: When the curing is complete, cool down, add ammonium sulfate at a ratio of 2.5% of the total weight, stir evenly, filter, and discharge to obtain anionic water-in-water green cleaning papermaking additive B2.

[0026] Example 3: A method for preparing an anionic water-in-water papermaking additive includes the following steps: Step 1: Add 500g of deionized water to the reactor, along with 200g of acrylic acid and N-vinylmorpholine in a mass ratio of 3:1. After deoxygenation for 30 minutes, when the reactor temperature reaches 40℃, add 0.1% sodium persulfate initiator (based on the total mass of acrylic acid and N-vinylmorpholine). When the reaction reaches a maximum temperature of 65℃, maintain the maximum temperature at 65℃ for 3 hours to obtain anionic dispersant A3.

[0027] Step 2: Add 44.41% deionized water, 5% anionic dispersant A3, 0.01% tetrasodium ethylenediaminetetraacetate, 17% acrylamide, 28% aluminum sulfate, and 3% acrylic acid by weight into the reaction vessel and stir to dissolve. Adjust the pH of the entire system to 7.23 with ammonia and purge with nitrogen for 30 minutes.

[0028] Step 3: When the temperature of the reactor reaches 20°C, add 0.01% sodium persulfate initiator by weight to the reactor and stir evenly. Then add 0.01% sodium metabisulfite initiator by weight. Wait for the reaction to slow down, and then add 0.01% sodium persulfate initiator and 0.01% sodium metabisulfite initiator by weight. Repeat this process intermittently (4 times in total) until the reaction reaches the highest temperature of 60°C. Maintain the reaction at the highest temperature of 60°C for 3 hours.

[0029] Step 4: When the curing is complete, cool down, add ammonium sulfate at a ratio of 2.5% of the total weight, stir evenly, filter, and discharge to obtain anionic water-in-water green cleaning papermaking additive B3.

[0030] Comparative Example 1: A method for preparing an anionic water-in-water papermaking additive includes the following steps: Step 1: Add 500g of deionized water and 200g of acrylic acid to the reactor. After deoxygenation for 30 minutes, when the reactor temperature reaches 45℃, add 0.1% sodium persulfate initiator (based on the total weight of acrylic acid) to the reactor. When the reaction reaches the maximum temperature of 65℃, maintain the maximum temperature of 65℃ for 3 hours to obtain anionic dispersant C1.

[0031] Step 2: Add 48.89% deionized water, 3% anionic dispersant C1, 0.03% disodium ethylenediaminetetraacetate, 15% acrylamide, 25% aluminum sulfate, and 3% acrylic acid by weight into the reaction vessel and stir to dissolve. Adjust the pH of the entire system to 7.2 with ammonia and purge with nitrogen for 30 minutes.

[0032] Step 3: When the temperature of the reactor reaches 25°C, add 0.01% sodium persulfate initiator by weight to the reactor and stir well. Then add 0.01% sodium metabisulfite initiator by weight. Wait for the reaction to slow down, and then add 0.01% sodium persulfate initiator and 0.01% sodium metabisulfite initiator by weight. Repeat this process intermittently (4 times in total) until the reaction reaches the highest temperature of 60°C. Maintain the reaction at the highest temperature of 60°C for 3 hours.

[0033] Step 4: When the curing is complete, cool down, add 5% ammonium sulfate by weight, stir evenly, filter, and discharge to obtain anionic water-in-water green cleaning papermaking additive D1.

[0034] Comparative Example 2: A method for preparing an anionic water-in-water papermaking additive includes the following steps: Step 1: Add 500g of deionized water to the reactor, along with 200g of acrylic acid and N-vinylmorpholine in a mass ratio of 3:1. After deoxygenation for 30 minutes, when the reactor temperature reaches 45℃, add 0.1% sodium persulfate initiator (based on the total mass of acrylic acid and N-vinylmorpholine). When the reaction reaches a maximum temperature of 65℃, maintain the maximum temperature at 65℃ for 3 hours to obtain anionic dispersant C2.

[0035] Step 2: Add 48.89% deionized water, 3% anionic dispersant C2, 0.03% disodium ethylenediaminetetraacetate, 15% acrylamide, 25% ammonium sulfate, and 3% acrylic acid by weight into the reaction vessel and stir to dissolve. Adjust the pH of the entire system to 7.2 with ammonia and purge with nitrogen for 30 minutes.

[0036] Step 3: When the temperature of the reactor reaches 25°C, add 0.01% sodium persulfate initiator by weight to the reactor and stir well. Then add 0.01% sodium metabisulfite initiator by weight. Wait for the reaction to slow down, and then add 0.01% sodium persulfate initiator and 0.01% sodium metabisulfite initiator by weight. Repeat this process intermittently (4 times in total) until the reaction reaches the highest temperature of 60°C. Maintain the reaction at the highest temperature of 60°C for 3 hours.

[0037] Step 4: When the curing is complete, cool down, add 5% ammonium sulfate by weight, stir evenly, filter, and discharge to obtain anionic water-in-water green cleaning papermaking additive D2.

[0038] Test Example 1: The papermaking additives prepared in Examples 1-3 and Comparative Examples 1-2 were tested for their paper-strengthening effect. The papermaking dry strength agent (i.e., the papermaking additive) was diluted with water to a mass concentration of 1%. Pulp was prepared, and the diluted papermaking dry strength agent was added to the pulp at a rate of 12 kg / t. The pulp was stirred evenly, formed into sheets, dried, and then subjected to performance testing. The test standard was GB / T 24323-2009, and the results are shown in Table 1.

[0039] Table 1 Paper Strength Performance Test Table

[0040] Discussion 1: The results in Table 1 show that the papermaking additives prepared in Examples 1-3 of this invention, as dry strength agents, can significantly improve the burst strength, burst index, and folding endurance of paper. The difference between Comparative Example 1 and Example 1 lies in the presence or absence of N-vinylmorpholine in the dispersant. Data in Table 1 indicates that Comparative Example 1 did not contain N-vinylmorpholine; instead, an anionic dispersant was obtained by polymerization of acrylic acid monomers, and further, a papermaking additive was prepared. The paper using this additive showed a decrease in burst strength, burst index, and folding endurance, and its strengthening effect was significantly lower than that of Example 1. In Comparative Example 2, the inorganic salt was ammonium sulfate, and a papermaking additive was further prepared. The paper using this additive also showed a certain decrease in burst strength, burst index, and folding endurance, and its strengthening effect was also significantly lower than that of Example 1.

[0041] Test Example 2: The papermaking additives prepared in Examples 1-3 and Comparative Examples 1-2 were tested for retention and filtration performance. The specific test methods are as follows: (1) Retention and filtration performance test: The paper basis weight was set to 60 g / m 2 The talc powder addition was 15 wt%, and the weight of a single sheet of handmade paper was 1.884 g, containing 1.6014 g of oven-dry pulp and 0.2826 g of talc powder. The oven-dry weight of the paper stock was the sum of the oven-dry pulp and talc powder weights. This stock was placed in a 1000 mL beaker, water was added, and the stock was dispersed evenly with a stirrer. 0.06% (based on oven-dry pulp) of the reagent (i.e., the retention and filtration aid prepared in the examples and comparative examples) was added to the dispersed stock, and stirring was continued for 5 minutes. The stock was then formed on a papermaking machine, and the paper was then handmade. Papermaking is dried at a constant temperature of 105℃; after drying the handmade paper with retention aid in a forced-air drying oven at 105℃ for 5 hours, the weight of the dried handmade paper is taken as the absolute dry weight of the paper sheet, and then the paper retention rate is calculated using the following formula: Paper retention rate % = Absolute dry weight of paper sheet × 100% / Absolute dry weight of paper sheet; 2g of absolute dry pulp is accurately weighed, water is added and dispersed evenly with a stirrer, and then 0.06% (based on absolute dry pulp) of reagent (i.e., the retention aid and filter aid prepared in the examples and comparative examples) is added, stirred for 5 minutes, and finally accurately prepared into 1000mL of pulp. The beating degree is measured as the filter aid performance; Table 2 Filter aid performance test

[0042] Discussion 2: As shown in Table 2, the papermaking additives prepared in Examples 1-3 of this invention, when added to pulp for papermaking as retention and filtration aids, can effectively improve the fiber retention rate of the wire section during papermaking and prevent the loss of fine fibers and fillers. The difference between Example 1 and Comparative Example 2 lies in whether aluminum sulfate is used as the dispersion medium. Adding aluminum sulfate as a dispersion medium has excellent effects on retention and filtration. As shown in Table 2, Comparative Example 2 did not add aluminum sulfate, resulting in a decrease in filtration effect. Therefore, aluminum sulfate can act as a dispersion medium in the system, facilitating the stable formation of the water-in-water system, and can also play a role in the application of retention and filtration aids in papermaking.

[0043] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A process for the preparation of an anionic water-in-water papermaking aid characterized in that, include: Deionized water, anionic monomer b, and functional monomer were added to the reactor. The mixture was deoxygenated for 15–30 minutes. When the reactor temperature reached 40–50°C, initiator b was added to the reactor. When the reaction reached 60–90°C, the mixture was aged at the current temperature for 2–5 hours to obtain an anionic dispersant. The functional monomer was N-vinylmorpholine. Deionized water, the anionic dispersant, the metal ion chelating agent, acrylamide, inorganic salt, and anionic monomer a are sequentially added to a reaction vessel and stirred to dissolve. The pH of the entire system is adjusted to 6-8 using an alkaline substance, and nitrogen is purged for 20-30 minutes. The inorganic salt is aluminum sulfate. When the temperature of the reactor reaches 20-40°C, add the initiator intermittently to the reactor, wait for the reaction to rise to 50-80°C, and maintain the current temperature for 1-3 hours to mature. Once the curing process is complete, the temperature is lowered, a post-treatment agent is added, the mixture is stirred evenly, filtered, and discharged to obtain the anionic water-in-water papermaking additive.

2. The method for preparing the anionic water-in-water papermaking additive according to claim 1, characterized in that, The anionic monomer b is one or more of acrylic acid, itaconic acid, 2-acrylamide-2-methylpropanesulfonic acid, maleic acid, and methylpropanesulfonic acid. The mass ratio of the anionic monomer b to the functional monomer is 3:1 to 6:

1.

3. The preparation method of the anionic water-in-water papermaking additive according to claim 1, characterized in that, The initiator b is one or more of sodium persulfate, potassium persulfate, and ammonium persulfate; The amount of initiator b is 0.1%-0.4% of the total mass of anionic monomer b and functional monomer.

4. The preparation method of the anionic water-in-water papermaking additive according to claim 1, characterized in that, The viscosity-average molecular weight of the anionic dispersant is 200,000 to 500,000.

5. The method for preparing the anionic water-in-water papermaking additive according to claim 1, characterized in that, The amount of the anionic dispersant is 1% to 5% of the total weight of the entire reaction system.

6. The method for preparing the anionic water-in-water papermaking additive according to claim 1, characterized in that, The metal ion chelating agent is one or more of sodium citrate, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium gluconate, and sodium tripolyphosphate; the amount of the metal ion chelating agent is 0.01% to 0.05% of the total weight of the entire reaction system; The inorganic salts are used in an amount that accounts for 20% to 28% of the total weight of the entire reaction system. The anionic monomer a is one or more of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and methacrylic acid; the molar ratio of acrylamide to anionic monomer a is 4 to 7, and the total mass of anionic monomer a and acrylamide accounts for 15 to 20% of the total weight of the entire reaction system.

7. The method for preparing the anionic water-in-water papermaking additive according to claim 1, characterized in that, The alkaline substance is one of sodium hydroxide, potassium hydroxide, or ammonia water; The initiator is a redox initiator, wherein the oxidant is one of sodium persulfate, ammonium persulfate, and potassium persulfate, and the reducing agent is sodium bisulfite and / or sodium metabisulfite; the oxidant and reducing agent are added intermittently and alternately, and the amount of redox initiator accounts for 0.05% to 0.1% of the total weight of the entire reaction system; The post-treatment agent is one or more of citric acid, ammonium sulfate, and ammonium adipate, and the amount of the post-treatment agent accounts for 2.5% to 6.25% of the total weight of the entire reaction system.

8. An anionic water-in-water papermaking additive obtained by the preparation method of the anionic water-in-water papermaking additive according to any one of claims 1 to 7, wherein the viscosity-average molecular weight of the polyacrylamide in the papermaking additive is 8 million to 12 million.

9. The application of the anionic water-in-water papermaking additive of claim 8 as a papermaking dry strength agent and / or retention and filtration aid.

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