阅读说明：本技术 一种耐盐碱高吸水树脂及其制备方法 (Saline-alkali-resistant super absorbent resin and preparation method thereof ) 是由 杨林 齐文 陈艳丽 谭淑樱 李星纬 刘畅 刘联 徐琰 佟鹏 张瀚文 戚丁文 张 于 2021-11-01 设计创作，主要内容包括：本发明公开了一种耐盐碱高吸水树脂的制备方法,该方法以可再生的松香为原料,通过与顺丁烯二酸酐反应,进一步酸化、酰化,再与丙烯酸羟酯、多元醇、多元胺及醇胺等反应,制备得到了含有多吸水基团的可聚合松香,进而与丙烯酸等通过自由基共聚,将含有多吸水基团的松香基引入到高吸水树脂分子结构中。本发明制得的高吸水树脂,具有优良的耐盐碱性,同时吸水速度、保水性及凝胶强度得到改善,高吸水树脂的整体综合性能得到进一步提升,扩大了高吸水树脂的应用领域。(The invention discloses a preparation method of saline-alkali resistant super absorbent resin, which takes reproducible rosin as a raw material, and the reproducible rosin is reacted with maleic anhydride, further acidified and acylated, and then reacted with hydroxy acrylate, polyalcohol, polyamine, alcohol amine and the like to prepare polymerizable rosin containing multiple water-absorbing groups, and further the polymerizable rosin is copolymerized with acrylic acid and the like through free radicals to introduce rosin groups containing multiple water-absorbing groups into the molecular structure of the super absorbent resin. The super absorbent resin prepared by the invention has excellent saline-alkali resistance, and meanwhile, the water absorption speed, the water retention property and the gel strength are improved, the overall comprehensive performance of the super absorbent resin is further improved, and the application field of the super absorbent resin is expanded.)

1. A preparation method of saline-alkali resistant super absorbent resin is characterized by comprising the following steps:

step 1: heating rosin to 120-190 ℃ under the protection of nitrogen, keeping the temperature for 1-4 hours, slowly adding maleic anhydride, heating for reaction for 3-15 hours, finishing the reaction, and cooling to room temperature to obtain a product I;

step 2: washing the product I with carbon tetrachloride for 2-3 times, and recrystallizing with acetic acid for 1-2 times to obtain a product II;

and step 3: dissolving the product II in 1mol/L sodium hydroxide or potassium hydroxide solution, performing high-temperature pressure reaction for 4-15 h in high-pressure equipment at the temperature of 180-230 ℃, finishing the reaction, cooling, neutralizing to be neutral by using hydrochloric acid solution, and filtering, washing and drying to obtain a product III;

and 4, step 4: adding an acid-binding agent into the product III, mixing uniformly, slowly adding an acylation reagent at 0-60 ℃, after dropwise adding, performing reflux reaction for 1-10 h, finishing the reaction, and separating to remove redundant acylation reagent to obtain a product IV;

and 5: adding a solvent into the product IV to prepare a solution with the mass concentration of 3-60%, adding hydroxyl acrylate, an acid-binding agent and/or one or more of polyol, polyamine and alcohol amine into the solution, reacting for 4-60 h under the protection of nitrogen and at the temperature of 0-80 ℃, finishing the reaction, and washing, precipitating and separating to obtain a product V for later use;

step 6: taking acrylic acid, and neutralizing with 5-30% sodium hydroxide or potassium hydroxide solution by mass fraction under ice bath condition to obtain neutralized acrylic acid solution for later use;

and 7: adding 0.05-5% of dispersant and 5-85% of dispersion medium by mass into a water bath at 20-60 ℃, stirring until the dispersant is completely dissolved, then adding 10-60% of neutralized acrylic acid solution by mass, 5-20% of product V by mass, 0.005-10% of cross-linking agent by mass and/or 0-60% of comonomer by mass, and stirring until the components are completely dissolved to obtain a reaction system;

and 8: and (2) dropwise adding an initiator system with the mass fraction of 0.01-5% into the reaction system, raising the reaction temperature to 40-70 ℃, reacting for 1-8 h, finishing the reaction, removing water and a dispersion medium, washing for 3-6 times by using ethanol, drying, and crushing to obtain the saline-alkali resistant super absorbent resin.

2. The method for preparing the saline-alkali resistant super absorbent resin according to claim 1, wherein the acid-binding agent is one or more of triethylamine, pyridine, N-dimethylformamide, N-dimethylacetamide, N-diisopropylethylamine, and 4-dimethylaminopyridine; the acylating reagent is one of thionyl chloride, oxalyl chloride, phosphorus trichloride and phosphorus pentachloride.

3. The method for preparing the saline-alkali resistant super absorbent resin as claimed in claim 1, wherein the hydroxyl acrylate is one or more of 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate and 5-hydroxypentyl acrylate.

4. The method for preparing the saline-alkali resistant super absorbent resin as claimed in claim 1, wherein the polyhydric alcohol is one or more of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, hexylene glycol, glycerol, isopropanol and pentaerythritol; the polyamine is one or more of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, diethylamine and triethylamine; the alcohol amine is one or more of ethanolamine, propanolamine and butanol amine.

5. The method for preparing the saline-alkali resistant super absorbent resin as claimed in claim 1, wherein the dispersant is Hypermer B261, Span-60, Span-80, OP-100; the dispersion medium is one or more of cyclohexane, hexane and heptane.

6. The method for preparing the saline-alkali resistant super absorbent resin as claimed in claim 1, wherein the cross-linking agent is one or more of N, N-methylenebisacrylamide, divinylbenzene, glycerol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate and diallyldimethylammonium chloride.

7. The method for preparing the saline-alkali resistant super absorbent resin as claimed in claim 1, wherein the comonomer is one or more of acrylamide, polyoxyethylene allyl ether, pentaerythritol allyl ether, 2-acrylamido-2-methylpropanesulfonic acid, and maleic anhydride.

8. The method for preparing the saline-alkali resistant super absorbent resin according to claim 1, wherein the initiator system is one or more of an aqueous solution of ammonium persulfate, an aqueous solution of potassium persulfate, an aqueous solution of ammonium persulfate-urea, an aqueous solution of ammonium persulfate-N-isopropylhydroxylamine, ammonium persulfate-sodium sulfite, and an aqueous solution of hydrogen peroxide-ferrous sulfate.

9. A saline-alkali tolerant superabsorbent resin, characterized in that it is a resin prepared according to the method of any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of super absorbent resin, in particular to saline-alkali resistant super absorbent resin and a preparation method thereof.

Background

The super absorbent resin is a general name of high polymer with high water absorption performance and water retention performance, is a novel functional polymer material, and has wide application prospect in the aspects of medicine, physiological health, petroleum, building materials, daily necessities and the like. With the progress of the preparation technology of the super absorbent resin, the main performance indexes of the super absorbent resin, such as water absorption rate, gel strength and the like, in the ideal environment of pure water are greatly improved. However, with the gradual expansion of the application field, the working environment of the actual water-absorbing material is far from ideal, and the water-absorbing expansion performance of the super absorbent resin is often unsatisfactory and the application is limited due to the environments of saline-alkali-containing electrolyte solutions such as seawater, rainwater, river water, urine, blood, underground water and the like, so that the development of a novel saline-alkali-resistant super absorbent resin is imperative.

Disclosure of Invention

In view of the above, the invention discloses a saline-alkali resistant super absorbent resin and a preparation method thereof, so as to improve the saline-alkali resistance of the super absorbent resin, improve the water absorption speed, the water retention property and the gel strength, improve the overall comprehensive performance of the super absorbent resin, and expand the application range of the super absorbent resin.

The technical scheme provided by the invention is specifically that a preparation method of saline-alkali resistant super absorbent resin comprises the following steps:

step 1: heating rosin to 120-190 ℃ under the protection of nitrogen, keeping the temperature for 1-4 hours, slowly adding maleic anhydride, heating for reaction for 3-15 hours, finishing the reaction, and cooling to room temperature to obtain a product I;

the raw material rosin adopted in the step 1 is natural resin obtained by distilling viscous liquid secreted by pine trees, is an important renewable resource, and becomes an important raw material source for preparing high polymer materials after cellulose, lignin, starch, chitin, chitosan, natural rubber and the like. The rosin structure is basically resin acid of tricyclic phenanthrene skeleton containing two double-bond monoacid, and the resin acid can be isomerized mutually when heated, and further can be chemically modified to prepare the polymerizable rosin derivative with multiple carboxyl, hydroxyl or amino water-absorbing groups. The polymerizable rosin derivative is used as a raw material for synthesizing the super absorbent resin, so that diversified water-absorbing groups can be introduced, and the saline-alkali resistance of the resin is improved; the rosin molecular structure provides larger steric hindrance, and is also favorable for improving the space stability of the resin cross-linked network structure and improving the water absorption speed and the water retention; in addition, the rigid structure of the rosin molecules is beneficial to improving the gel strength and improving the comprehensive performance of the super absorbent resin.

Step 2: washing the product I with carbon tetrachloride for 2-3 times, and recrystallizing with acetic acid for 1-2 times to obtain a product II;

and step 3: dissolving the product II in 1mol/L sodium hydroxide or potassium hydroxide solution, performing high-temperature pressure reaction for 4-15 h in high-pressure equipment at the temperature of 180-230 ℃, finishing the reaction, cooling, neutralizing to be neutral by using hydrochloric acid solution, and filtering, washing and drying to obtain a product III;

and 4, step 4: adding an acid-binding agent into the product III, mixing uniformly, slowly adding an acylation reagent at 0-60 ℃, after dropwise adding, performing reflux reaction for 1-10 h, finishing the reaction, and separating to remove redundant acylation reagent to obtain a product IV;

and 5: adding a solvent into the product IV to prepare a solution with the mass concentration of 3-60%, adding hydroxyl acrylate, an acid-binding agent and/or one or more of polyol, polyamine and alcohol amine into the solution, reacting for 4-60 h under the protection of nitrogen and at the temperature of 0-80 ℃, finishing the reaction, and washing, precipitating and separating to obtain a product V for later use;

step 6: taking acrylic acid, and neutralizing with 5-30% sodium hydroxide or potassium hydroxide solution by mass fraction under ice bath condition to obtain neutralized acrylic acid solution for later use;

and 7: adding 0.05-5% of dispersant and 5-85% of dispersion medium by mass into a water bath at 20-60 ℃, stirring until the dispersant is completely dissolved, then adding 10-60% of neutralized acrylic acid solution by mass, 5-20% of product V by mass, 0.005-10% of cross-linking agent by mass and/or 0-60% of comonomer by mass, and stirring until the components are completely dissolved to obtain a reaction system;

and 8: and (2) dropwise adding an initiator system with the mass fraction of 0.01-5% into the reaction system, raising the reaction temperature to 40-70 ℃, reacting for 1-8 h, finishing the reaction, removing water and a dispersion medium, washing for 3-6 times by using ethanol, drying, and crushing to obtain the saline-alkali resistant super absorbent resin.

Preferably, the acid-binding agent is one or more of triethylamine, pyridine, N-dimethylformamide, N-dimethylacetamide, N-diisopropylethylamine and 4-dimethylaminopyridine; the acylating reagent is one of thionyl chloride, oxalyl chloride, phosphorus trichloride and phosphorus pentachloride.

Preferably, the hydroxyl acrylate is one or more of 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate and 5-hydroxypentyl acrylate.

Preferably, the polyalcohol is one or more of ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol, glycerol, isopropanol and pentaerythritol; the polyamine is one or more of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, diethylamine and triethylamine; the alcohol amine is one or more of ethanolamine, propanolamine and butanol amine.

Preferably, the dispersant is Hypermer B261, Span-60, Span-80, OP-100; the dispersion medium is one or more of cyclohexane, hexane and heptane.

Preferably, the cross-linking agent is one or more of N, N-methylene bisacrylamide, divinylbenzene, glycerol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate and diallyldimethylammonium chloride.

Preferably, the comonomer is one or more of acrylamide, allyl alcohol polyoxyethylene ether, pentaerythritol allyl ether, 2-acrylamido-2-methylpropanesulfonic acid and maleic anhydride.

Preferably, the initiator system is one or more of an aqueous solution of ammonium persulfate, an aqueous solution of potassium persulfate, an aqueous solution of ammonium persulfate-urea, an aqueous solution of ammonium persulfate-N-isopropylhydroxylamine, ammonium persulfate-sodium sulfite and an aqueous solution of hydrogen peroxide-ferrous sulfate.

The invention provides a preparation method of a saline-alkali resistant super absorbent resin, which is characterized in that renewable rosin is used as a raw material from the aspect of molecular structure design, a rosin group containing a plurality of water-absorbing groups is introduced into a molecular structure of the super absorbent resin through chemical modification, the water absorption rate and the water retention rate of the obtained saline-alkali resistant super absorbent resin are obviously improved, the saline-alkali resistant super absorbent resin has good liquid absorption and liquid retention in 0.9% saline solution and 5% alkaline solution, the gel strength of the saline-alkali resistant super absorbent resin is also obviously improved after liquid absorption, and the application field of the super absorbent resin is further expanded.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Detailed Description

In order to solve the problem of poor water absorption expansion performance of the water-absorbent resin in the saline-alkali electrolyte solution environment in the prior art, the embodiment provides a preparation method of saline-alkali resistant super absorbent resin, which comprises the following steps:

step 1: heating rosin to 120-190 ℃ under the protection of nitrogen, keeping the temperature for 1-4 hours, slowly adding maleic anhydride, heating for reaction for 3-15 hours, finishing the reaction, and cooling to room temperature to obtain a product I;

step 2: washing the product I with carbon tetrachloride for 2-3 times, and recrystallizing with acetic acid for 1-2 times to obtain a product II;

and step 3: dissolving the product II in 1mol/L sodium hydroxide or potassium hydroxide solution, performing high-temperature pressure reaction for 4-15 h in high-pressure equipment at the temperature of 180-230 ℃, finishing the reaction, cooling, neutralizing to be neutral by using hydrochloric acid solution, and filtering, washing and drying to obtain a product III;

and 4, step 4: adding an acid-binding agent into the product III, mixing uniformly, slowly adding an acylation reagent at 0-60 ℃, after dropwise adding, performing reflux reaction for 1-10 h, finishing the reaction, and separating to remove redundant acylation reagent to obtain a product IV;

and 5: adding a solvent into the product IV to prepare a solution with the mass concentration of 3-60%, adding hydroxyl acrylate, an acid-binding agent and/or one or more of polyol, polyamine and alcohol amine into the solution, reacting for 4-60 h under the protection of nitrogen and at the temperature of 0-80 ℃, finishing the reaction, and washing, precipitating and separating to obtain a product V for later use;

step 6: taking acrylic acid, and neutralizing with 5-30% sodium hydroxide or potassium hydroxide solution by mass fraction under ice bath condition to obtain neutralized acrylic acid solution for later use;

and 7: adding 0.05-5% of dispersant and 5-85% of dispersion medium by mass into a water bath at 20-60 ℃, stirring until the dispersant is completely dissolved, then adding 10-60% of neutralized acrylic acid solution by mass, 5-20% of product V by mass, 0.005-10% of cross-linking agent by mass and/or 0-60% of comonomer by mass, and stirring until the components are completely dissolved to obtain a reaction system;

and 8: and (2) dropwise adding an initiator system with the mass fraction of 0.01-5% into the reaction system, raising the reaction temperature to 40-70 ℃, reacting for 1-8 h, finishing the reaction, removing water and a dispersion medium, washing for 3-6 times by using ethanol, drying, and crushing to obtain the saline-alkali resistant super absorbent resin.

Preferably, the maleic anhydride, carbon tetrachloride, acetic acid, sodium hydroxide and potassium hydroxide are reagents with purity higher than chemical purity; the solvent is one or more of tetrahydrofuran, carbon tetrachloride, ethyl acetate, butyl acetate, pyridine and dichloromethane;

preferably, the acid-binding agent is one or more of triethylamine, pyridine, N-dimethylformamide, N-dimethylacetamide, N-diisopropylethylamine and 4-dimethylaminopyridine; the acylating reagent is one of thionyl chloride, oxalyl chloride, phosphorus trichloride and phosphorus pentachloride;

preferably, the hydroxyl acrylate is one or more of 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate and 5-hydroxypentyl acrylate;

preferably, the polyalcohol is one or more of ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hexanediol, glycerol, isopropanol and pentaerythritol; the polyamine is one or more of ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, hexylenediamine, diethylamine and triethylamine; the alcohol amine is one or more of ethanolamine, propanolamine and butanolamine;

preferably, the dispersant is Hypermer B261, Span-60, Span-80, OP-100; the dispersion medium is one or more of cyclohexane, hexane and heptane;

preferably, the cross-linking agent is one or more of N, N-methylene bisacrylamide, divinylbenzene, glycerol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate and diallyl dimethyl ammonium chloride;

preferably, the comonomer is one or more of acrylamide, allyl polyoxyethylene ether, pentaerythritol allyl ether, 2-acrylamido-2-methylpropanesulfonic acid and maleic anhydride;

preferably, the initiator system is one or more of an aqueous solution of ammonium persulfate, an aqueous solution of potassium persulfate, an aqueous solution of ammonium persulfate-urea, an aqueous solution of ammonium persulfate-N-isopropylhydroxylamine, ammonium persulfate-sodium sulfite and an aqueous solution of hydrogen peroxide-ferrous sulfate.

In the method provided by the embodiment, by introducing diversified water-absorbing groups, nonionic groups are added, and the sensitivity of ionic groups to the external electrolyte environment is reduced; selecting a proper cross-linking agent to form an interpenetrating network structure; the salt-tolerant water-absorbent resin is compounded with other salt-tolerant inorganic components, and through molecular design, the water-absorbing groups of the water-absorbent resin synthetic raw materials are optimized, the cross-linked net structure is optimized, and the stability of the net structure is improved, so that the salt and alkali tolerance of the water-absorbent resin is remarkably improved.

The saline-alkali electrolyte solution environment often makes the water-absorbing expansion performance of the super absorbent resin unsatisfactory, and the application is limited, so that the development of a novel saline-alkali resistant super absorbent resin is imperative.

Finally, the embodiment provides a saline-alkali resistant super absorbent resin, which is prepared by the method; the detection shows that the gel has good liquid absorption and retention in 0.9% saline solution and 5% alkali solution, and the gel strength is also obviously improved after the absorption.

The present invention will be further illustrated by the following examples, but the present invention is not limited to these examples.

Example 1

Heating 100g of rosin to 180 ℃ under the protection of nitrogen, keeping the temperature for 2 hours, slowly adding 27g of maleic anhydride, heating for reaction for 12 hours, finishing the reaction, and cooling to room temperature to obtain a maleopimaric anhydride mixture containing unreacted rosin; washing the obtained maleopimaric anhydride mixture containing unreacted rosin with carbon tetrachloride for 3 times, removing the unreacted rosin, and recrystallizing with acetic acid for 2 times to obtain maleopimaric anhydride; dissolving 100g of maleopimaric anhydride in 1mol/L sodium hydroxide solution, carrying out high-temperature pressure reaction for 4 hours in high-pressure equipment at 200 ℃, ending the reaction, cooling, neutralizing to be neutral by using 0.1mol/L hydrochloric acid solution, filtering, washing and drying to obtain fumaropimaric acid containing three carboxyl groups; adding 23g of N, N-dimethylformamide into 42g of fumaropimaric acid, uniformly mixing, slowly adding 25g of oxalyl chloride at 40 ℃, refluxing for 6 hours after dropwise addition is finished, finishing the reaction, and separating and removing redundant oxalyl chloride to obtain fumaropimaric acid chloride; adding 21g of fumaropimaric acyl chloride into 21g of carbon tetrachloride/dichloromethane in a mass ratio of 1:1 to prepare a solution with a mass concentration of 50%, adding 6g of 2-hydroxyethyl acrylate, 11g of N, N-dimethylformamide and 3.1g of ethylene glycol into the solution, reacting for 48 hours under the protection of nitrogen and at 50 ℃, finishing the reaction, and washing, precipitating and separating to obtain polymerizable fumaropimaric acid ester containing carboxyl and hydroxyl for later use; taking acrylic acid, and neutralizing the acrylic acid with a sodium hydroxide solution with the mass fraction of 10% under an ice bath condition to obtain a neutralized acrylic acid solution for later use.

Adding 1% by mass of Hypermer B261 and 25% by mass of cyclohexane into a water bath at 30 ℃, stirring until the dispersant Hypermer B261 is completely dissolved, then adding 40% by mass of a neutralized acrylic acid solution, 5% by mass of polymerizable fumaropimaric acid ester, 1% by mass of N, N-methylenebisacrylamide and 25% by mass of 2-acrylamido-2-methylpropanesulfonic acid, and stirring until the materials are completely dissolved to obtain a reaction system; and (2) dropwise adding 3% ammonium persulfate-urea aqueous solution into the reaction system, raising the reaction temperature to 40 ℃, reacting for 6 hours, finishing the reaction, removing water and a dispersion medium, washing for 4 times by using ethanol, drying, and crushing to obtain the saline-alkali resistant super absorbent resin.

Compared with the common polyacrylic acid super absorbent resin sold in the market, the super absorbent resin prepared by the method has the advantages that the water absorption rate is improved by 67 percent, the liquid absorption rate in saline water with the concentration of 0.9 percent by mass is improved by 24 percent, and the liquid absorption rate in Ca (OH) with the concentration of 5 percent by mass₂The liquid absorption rate in the solution is improved by 18 percent, and the gel strength is improved by 20 percent.

Example 2

Heating 100g of rosin to 180 ℃ under the protection of nitrogen, keeping the temperature for 2 hours, slowly adding 27g of maleic anhydride, heating for reaction for 12 hours, finishing the reaction, and cooling to room temperature to obtain a maleopimaric anhydride mixture containing unreacted rosin; washing the obtained maleopimaric anhydride mixture containing unreacted rosin with carbon tetrachloride for 3 times, removing the unreacted rosin, and recrystallizing with acetic acid for 2 times to obtain maleopimaric anhydride; dissolving 100g of maleopimaric anhydride in 1mol/L sodium hydroxide solution, carrying out high-temperature pressure reaction for 4 hours in high-pressure equipment at 200 ℃, ending the reaction, cooling, neutralizing to be neutral by using 0.1mol/L hydrochloric acid solution, filtering, washing and drying to obtain fumaropimaric acid containing three carboxyl groups; adding 31g of triethylamine into 42g of fumaropimaric acid, uniformly mixing, slowly adding 36g of thionyl chloride at 20 ℃, after dropwise adding, carrying out reflux reaction for 4 hours, finishing the reaction, and separating and removing redundant thionyl chloride to obtain fumaropimaric acid chloride; adding 21g of fumaropimaric acid chloride into 14g of pyridine/dichloromethane in a mass ratio of 3:1 to prepare a solution with a mass concentration of 60%, adding 3.2g of hydroxypropyl 3-acrylate, 3.6g of hydroxybutyl 4-acrylate, 11g of N, N-dimethylformamide and 9g of butanediamine into the solution, reacting for 18 hours at 20 ℃ under the protection of nitrogen, finishing the reaction, washing, precipitating and separating to obtain polymerizable fumaropimaric acid ester containing amino groups for later use; taking acrylic acid, and neutralizing the acrylic acid with a sodium hydroxide solution with the mass fraction of 15% under an ice bath condition to obtain a neutralized acrylic acid solution for later use.

Adding 0.5 mass percent of Span-80 and 40 mass percent of cyclohexane into a water bath at 50 ℃, stirring until the dispersant Span-80 is completely dissolved, then adding 20 mass percent of neutralized acrylic acid solution, 10 mass percent of polymerizable fumaropimaric acid ester, 0.5 mass percent of divinylbenzene, 10 mass percent of acrylamide and 18 mass percent of propenol polyoxyethylene ether, stirring until the materials are completely dissolved, and obtaining a reaction system; and (2) dropwise adding a potassium persulfate aqueous solution with the mass fraction of 1% into the reaction system, raising the reaction temperature to 60 ℃, reacting for 4 hours, finishing the reaction, removing water and cyclohexane, washing for 3 times by using ethanol, drying, and crushing to obtain the saline-alkali-resistant super absorbent resin.

Compared with the common polyacrylic acid super absorbent resin sold in the market, the super absorbent resin prepared by the method has higher water absorption rate55 percent, the liquid absorption rate in 0.9 percent concentration saline is improved by 28 percent, and the concentration in 5 percent Ca (OH)₂The liquid absorption rate in the solution is improved by 21 percent, and the gel strength is improved by 25 percent.

Example 3

Heating 100g of rosin to 180 ℃ under the protection of nitrogen, keeping the temperature for 2 hours, slowly adding 27g of maleic anhydride, heating for reaction for 12 hours, finishing the reaction, and cooling to room temperature to obtain a maleopimaric anhydride mixture containing unreacted rosin; washing the obtained maleopimaric anhydride mixture containing unreacted rosin with carbon tetrachloride for 3 times, removing the unreacted rosin, and recrystallizing with acetic acid for 2 times to obtain maleopimaric anhydride; dissolving 100g of maleopimaric anhydride in 1mol/L sodium hydroxide solution, carrying out high-temperature pressure reaction for 4 hours in high-pressure equipment at 200 ℃, ending the reaction, cooling, neutralizing to be neutral by using 0.1mol/L hydrochloric acid solution, filtering, washing and drying to obtain fumaropimaric acid containing three carboxyl groups; adding 8g of pyridine and 15g of N, N-dimethylformamide into 42g (0.1mol) of fumaropimaric acid, uniformly mixing, slowly adding 37g of oxalyl chloride at 40 ℃, refluxing for 8 hours after the dropwise addition is finished, finishing the reaction, and separating and removing redundant oxalyl chloride to obtain fumaropimaric chloride; adding 21g (0.05mol) of fumaropimaric acid chloride into 189g of tetrahydrofuran/ethyl acetate with the mass ratio of 2:1 to prepare a solution with the mass concentration of 10%, adding 7g of 5-hydroxypentyl acrylate, 11g of N, N-dimethylformamide, 4g of propylene glycol and 4g of butanediamine into the solution, reacting for 20 hours at 40 ℃ under the protection of nitrogen, finishing the reaction, washing, precipitating and separating to obtain polymerizable fumaropimaric acid ester containing hydroxyl and amino for later use; taking acrylic acid, and neutralizing the acrylic acid with a sodium hydroxide solution with the mass fraction of 5% under an ice bath condition to obtain a neutralized acrylic acid solution for later use.

Adding OP-100 with the mass fraction of 0.05%, Span-60 with the mass fraction of 0.10% and heptane with the mass fraction of 80% into a water bath at 20 ℃, stirring until a dispersing agent is completely dissolved, then adding a neutralized acrylic acid solution with the mass fraction of 10%, 5% of polymerizable fumaropimaric acid ester containing hydroxyl and amino, 0.04% of N, N-methylene bisacrylamide, 0.04% of diallyl dimethyl ammonium chloride and 4.7% of 2-acrylamido-2-methylpropanesulfonic acid, and stirring until the materials are completely dissolved to obtain a reaction system; and (2) dropwise adding 0.07% by mass of ammonium persulfate-N-isopropylhydroxylamine aqueous solution into the reaction system, raising the reaction temperature to 60 ℃, reacting for 8 hours, finishing the reaction, removing water and a dispersion medium, washing for 2 times by using ethanol, drying, and crushing to obtain the saline-alkali resistant super absorbent resin.

Compared with the common polyacrylic acid super absorbent resin sold in the market, the super absorbent resin prepared by the method has the advantages that the water absorption rate is improved by 62 percent, the liquid absorption rate in 0.9 percent saline is improved by 28 percent, and 5 percent of Ca (OH)₂The liquid absorption rate in the solution is improved by 21 percent, and the gel strength is improved by 20 percent.

Compared with the common polyacrylic acid super absorbent resin sold in the market, the super absorbent resin prepared by the method has the advantages that the water absorption rate is improved by 63 percent, the liquid absorption rate in saline water with the concentration of 0.9 percent by mass is improved by 32 percent, and the liquid absorption rate in Ca (OH) with the concentration of 5 percent by mass₂The liquid absorption rate in the solution is improved by 24 percent, and the gel strength is improved by 25 percent.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements shown and described above, and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.