CN102311600A - Manufacturing method of superabsorbent resin - Google Patents

Abstract

A simple method for producing a super absorbent resin, which can reduce the occurrence of gel blocking in an absorbent material by making the Absorption Rate Index (ARI) of the super absorbent resin at least 5 minutes.

Description

Manufacturing method of superabsorbent resin

technical field

The invention relates to a production method of superabsorbent resin.

Background technique

Superabsorbent resins are widely used as water retaining agents in agriculture or gardening, anti-dew condensation agents in building materials, water removers for removing moisture from oil, or outer waterproof coating agents in cables and Sanitary products such as diapers, feminine hygiene products, disposable wipes, etc., are especially used in diapers.

Ultra-thin diapers are currently the main development direction. Since ultra-thin diapers must have a high-density absorbent layer, the mixture of superabsorbent resin and pulp fibers in this absorbent layer must have higher absorption capacity. In order to make full use of the absorbent layer The ability to store liquid, so the distribution of liquid in the absorbent layer becomes very important. In general, the reduction of pulp fibers in the absorbent layer has a negative effect on the distribution of liquid in the absorbent layer.

When the superabsorbent resin or pulp fiber in the absorbent layer absorbs liquid, the void space between the superabsorbent resin and pulp fiber or the pores in the superabsorbent resin will be closed due to rapid expansion, thus inhibiting the conduction of the liquid , causing the subsequent liquid to no longer penetrate the area that has absorbed the liquid and swell, this phenomenon is called gel-blocking (Gel-blocking); when this phenomenon occurs, the subsequent liquid can no longer penetrate the absorber, edge flow, resulting in leakage.

In addition, due to colloidal clogging of the superabsorbent resin near the swelling area, the rest of the liquid cannot reach the deeper part, so that the ability of the absorbent layer to store liquid is greatly reduced.

It is known in the art that the method of reducing colloid blocking is to change the absorption rate of superabsorbent resin (US Patent No. 4,548,847). The hydrogel formed by water-soluble compounds such as disodium acetate or ammonium hydrogen phosphate and containing at least one divalent metal ion can reduce the cross-link density in the hydrogel, making it easier for the superabsorbent resin to Absorb liquid.

EP 0631768A1 mentioned an absorber, which uses superabsorbent resins with different particle size distributions (the particle size range of type 1 is 600-850um, and the particle size range of type 2 is less than 250um), which further produces different The absorption speed of the absorber, but the difference in the absorption speed is not large.

US Patent No. 5,115,011 mentions an absorbent for absorbing blood and liquid, which uses a mixture of a superabsorbent resin and a halogen compound having a phosphoric acid group, a sulfite group or a sulfate group. This type of mixture is called a water-soluble mixture, which exists in the state of flowing powder at room temperature and is harmless to organisms; dissolving this mixture in unsaturated monomers for polymerization can increase the diffusion speed of the liquid. This patent also mentions the use of aluminum, calcium, magnesium sulfate, acetate or nitrate compound mixed with sulfurous acid monovalent metal salt or ammonium salt compound in less than 10% by weight, which can reduce the occurrence of colloidal blocking phenomenon.

In addition, U.S. Patent No. 5,578,318 uses water-soluble anionic compounds with carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups and polyvalent metals with a valence of at least 3, such as antimony (Antimony). The occurrence of colloidal blocking phenomenon.

The problem to be solved by the present invention is that ultra-thin diapers must have a high-density absorbing layer, especially an absorber with multiple absorbing layers to prevent colloid blocking, which is a very important technical problem. One of the methods to solve this problem is to infiltrate the superabsorbent resin into the superabsorbent resin absorber, which can make the superabsorbent resin absorb water slowly. However, the above-mentioned US patent methods cannot provide satisfactory slow superabsorbent resin. .

Mixing polyvalent metal salt solution of citrate or sulfate with superabsorbent resin can produce superabsorbent resin with low absorption rate, but the production efficiency is greatly reduced due to secondary processing. Increased manufacturing costs (US Patent Nos. 6,433,058, 6,579,958).

Contents of the invention

The purpose of the present invention is to provide a manufacturing method of superabsorbent resin to overcome the defects in the known technology.

In order to achieve the above object, the method for manufacturing superabsorbent resin provided by the present invention includes:

(i) in the superabsorbent resin particles with internal crosslinking structure generated by the free radical polymerization reaction of the acid group-containing monomer aqueous solution;

(ii) Adding 0.001 to 10% by weight of the total resin and a solution of a compound having a hydroxyl group or an amino group in an amount of 0.001 to 5% by weight of the total resin mixed with water and the superabsorbent resin particles A manufacturing method characterized by surface cross-linking reaction coating treatment by remixing.

The method for producing superabsorbent resin, wherein the general formula of the compound with hydroxyl or amine group is:

X-R-Y (1)

In the formula, R represents an alkyl compound with a carbon number of not less than 4 and a straight or branched chain;

X and Y are amino groups or hydroxyl groups.

The method for producing a superabsorbent resin, wherein the compound having a hydroxyl group or an amino group is selected from 1,4-butanediol, 1,4-butanediamine, 2-amino-1-butanol or 1,2 - Octanediol.

In the method for producing a superabsorbent resin, the surface crosslinking agent is selected from the group consisting of polyalcohol ethylene glycol and alkylene carbonate ethylene glycol carbonate.

Said method of producing a superabsorbent resin, wherein the absorption rate index (ARI) of the produced superabsorbent resin is at least 5 minutes.

The superabsorbent resin produced by the present invention has the characteristics of slow absorption speed and high absorption rate under high pressure, so the superabsorbent resin produced by the present invention will be more suitable for use in Various types of absorbent products for hygiene, agriculture and food preservation.

Detailed ways

In the present invention, further surface crosslinking reaction treatment is performed on the surface of the superabsorbent resin, and a superabsorbent resin with a slow water absorption rate can be obtained when adding a compound containing an amino group or a hydroxyl group, and the present invention is further completed.

Furthermore, the superabsorbent resin produced by the present invention has a slow absorption rate for synthetic urine, and its synthetic urine absorption rate index is at least 5 minutes. The Absorption Rate Index (ARI) of the above-mentioned synthetic urine refers to the Absorption Rate Index measured by the ARI test method described on page 7 of US Patent No. 6,433,058 specification.

The method for producing a superabsorbent resin of the present invention at least includes: making an aqueous solution of an acid group-containing monomer with a neutralization rate of 45 mole percent (mol%) to 85 mol% undergo free radical polymerization with a polymerization initiator to generate a superabsorbent resin In the hydrogel, the monomers of the acid group-containing monomer aqueous solution are selected from acrylic acid or methacrylic acid or 2-propenylamine-2-methylpropanesulfonic acid or a mixture of the above groups. Then, the above-mentioned gel body is cut into a small hydrogel body, and then dried, pulverized, and screened with hot air at a temperature of 100°C to 250°C to obtain a superabsorbent resin (a well-known technology in the art, the usual process for producing a superabsorbent resin technology), and then carry out surface cross-linking reaction treatment on the surface of the superabsorbent resin.

The present invention proposes a kind of superabsorbent resin with slow absorption speed and its preparation method which is different from the necessary technical features shared by the prior art. The surface of the treated superabsorbent resin is further bridged (surface cross-linking reaction), that is, adding a compound containing an amine group or a hydroxyl group to perform a surface cross-linking reaction. The addition method of the compound containing an amino group or a hydroxyl group can be:

(a) After being mixed with an aqueous solution of a surface crosslinking agent, it is coated on the surface of a superabsorbent resin to carry out a surface crosslinking reaction;

(b) before adding the surface cross-linking treatment, adding it to the surface of the super absorbent resin for surface cross-linking treatment;

(c) After adding the surface cross-linking treatment, add it to the super absorbent resin and add it in three ways.

The water-soluble unsaturated monomers used in the manufacture of superabsorbent resins, in addition to acrylic acid, can also use other water-soluble monomers with unsaturated double bonds containing acid groups, such as: methacrylic acid, maleic acid, fumaric acid acid, 2-propenylamine-2-methylpropanesulfonic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, etc. The selection of monomers is not limited to only one type, and multiple monomers can also be combined and used together. Other hydrophilic monomers with unsaturated double bonds can also be added according to the situation, such as: acrylamide, methacrylamide , 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, methyl acrylate, ethyl acrylate, dimethylamine acrylamide, acrylamide trimethylammonium chloride, but the amount added should not destroy the super absorbent The physical properties of the permanent resin are the principle.

When performing radical polymerization, the concentration of the aqueous monomer solution is not particularly limited, but the preferred concentration should be controlled between 20% by weight and 55% by weight, and the appropriate concentration is between 30% by weight and 45% by weight . When the concentration is controlled below 20% by weight, the polymerized hydrogel is too soft and viscous to be unfavorable for mechanical processing. The added concentration is above 55% by weight, which is close to the saturation concentration, and it is difficult to deploy and the reaction is too fast. The reaction heat is not easy control. The pH value of the unsaturated monomer aqueous solution is preferably controlled to not be lower than 5.5. If the pH is lower than 5.5, the residual monomer content in the hydrogel after polymerization is too high, resulting in poor physical properties of the superabsorbent resin.

Before free radical polymerization, water-soluble polymer compounds can also be added to the monomer aqueous solution to reduce costs, such as: partially saponified or fully saponified polyvinyl alcohol, polyethylene glycol, polyethylene glycol, etc. Acrylic acid, polyacrylamide, starch or starch derivatives such as methyl cellulose, methyl cellulose acrylate, ethyl cellulose and other polymers; the molecular weight of these water-soluble polymers is not particularly limited, and the preferred water-soluble The permanent polymer compound is starch, partially saponified or fully saponified polyvinyl alcohol, etc., which can be used alone or in combination. The superabsorbent resin contains these water-soluble polymer compounds in an appropriate weight percentage of 0 to 20 weight%, preferably 0 to 10 weight%, especially 0 to 5 weight%. When the additive amount exceeds 20 weight%, it will Affects physical properties and deteriorates physical properties.

Before free radical polymerization, a free radical polymerization crosslinking agent should be added to the unreacted monomer solution. The free radical polymerization crosslinking agent can be a compound with two or more unsaturated double bonds. Such as: N,N'-bis(2-propenyl)amine, N,N'-methine bisacrylamide, N,N'-methine bismethacrylamide, acrylate, ethylene glycol di Acrylates, Polyethylene glycol diacrylate, Polyethylene glycol dimethacrylate, Polyethylene glycol dimethacrylate, Glycerin triacrylate, Glycerin trimethacrylate, Glycerol with ethylene oxide added Acrylates or trimethacrylates, trimethylolpropane triacrylates or trimethacrylates with added ethylene oxide, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, N,N,N- Tris(2-propenyl)amine, ethylene glycol diacrylate, polyoxyethylene glycerol triacrylate, diethylpolyoxyethylene glycerol triacrylate, dipropylene triethylene glycol ester, and the like. Compounds with two or more epoxy groups can also be used, such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, poly Ethylene glycol diglycidyl ether, diglycerol polyglycidyl ether, etc. After the free radical reaction, the superabsorbent resin can have a proper degree of crosslinking, so that the colloid of the superabsorbent resin can have proper processability.

The free radical polymerization reaction crosslinking agent can be used alone or in combination of two or more, and its appropriate additive amount is between 0.001% by weight and 5% by weight (based on the total solid content of the reactants), and the more appropriate amount is by weight The percentage is between 0.01% and 3% by weight. If the additive amount is less than 0.001% by weight, the polymerized hydrated body is too soft and viscous to be unfavorable for mechanical processing; if the additive amount is above 5% by weight, the water absorption is too low and the performance of the resin will be reduced.

The carboxylic acid group of the acid group-containing monomer is used as a neutralizing agent to control the pH value of the finished product, making it neutral or slightly acidic. The neutralizing agent is the hydroxide or carbonate of the alkali metal group or alkaline earth group in the periodic table , such as: sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate or ammonia compounds. Neutralizers can be used alone or in combination. The carboxylic acid groups of the acid group-containing monomers are partially neutralized to form sodium salts, potassium salts or ammonium salts, and the molar percentage of the neutralization concentration is 45mol% to 85mol%, preferably 50mol% to 75mol%. When the molar percentage of neutralization concentration is below 45mol%, the pH value of the finished product is low; when the molar percentage of neutralization concentration is above 85mol%, the pH value of the finished product is high; Neither is suitable or safe for human contact.

Pre-polymerization, one of the processes for producing superabsorbent resin, starts with free radicals generated by the decomposition of a polymerization initiator. Polymerization initiator can be selected thermal decomposition type starter, suitable thermal decomposition type initiator has peroxide, such as: hydrogen peroxide, two-tertiary butyl peroxide, peroxide amide or persulfate (ammonium Salt, alkali metal salt), etc., and azo compounds such as: 2.2'-Azobis(2-amidinopropane) dihydrochloride, 2.2'-Azobis(N,N-dimethylene iso butamidine) dihydrochloride; also can use reducing agent to make it redox initiator, such as: acid sulfite, thiosulfate, ascorbic acid or ferrous salt; or redox initiator and Combined use of pyrolytic initiators. First of all, the redox initiator is the first to react to generate free radicals. When the free radicals are transferred to the monomer, the polymerization reaction will be initiated. Because a large amount of heat will be released during the polymerization reaction, the temperature will rise. When the temperature When the decomposition temperature of the thermal decomposition type initiator is reached, the decomposition of the second stage thermal decomposition type initiator will be initiated, and the whole polymerization reaction will be more complete. Generally, the appropriate amount of free radical polymerization initiator is 0.001 to 10% by weight (based on the weight of the neutralized acrylate), and the more appropriate amount is between 0.1 and 5% by weight, and 0.001% by weight is used. When it is less than 10% by weight, the reaction is too slow, which is unfavorable to economic benefits; when the weight percentage is more than 10% by weight, the reaction is too fast, the heat of reaction is not easy to control, and it is easy to overpolymerize to form a gel-like solid.

The polymerization reaction of the present invention can be carried out in a conventional batch reactor or in a conveyor belt reactor. The gel body obtained by the reaction is first cut into small gel bodies with a diameter of less than 20mm by a grinder, preferably less than 10mm, and then screened.

The diameter of the gel with a fixed particle size screened is preferably less than 2.00 mm, preferably between 0.05 mm and 1.50 mm. Due to the drying and crushing of gels with a particle size of less than 0.05mm, the amount of fine powder in the finished product is likely to increase, and the drying of gels with a particle size of more than 2.00mm is likely to cause residual products due to poor heat conduction. The monomer is too high, and the physical properties are not good; therefore, the gel with a particle size of more than 2.00mm and less than 0.05mm is sent back to the reactor for further reaction and crushing.

The drying temperature should be between 100°C and 180°C. If the drying temperature is below 100°C, it will not be economical if the drying time is too long. If the drying temperature is above 180°C, the crosslinking agent will undergo crosslinking reaction earlier. In the drying process, the residual monomer cannot be effectively removed due to the high cross-linking, so as to achieve the effect of reducing the residual monomer.

After drying, it is crushed, screened to fix the particle size, and then coated with a surface cross-linking agent. The suitable particle size for screening is between 0.05mm and 1.00mm, preferably between 0.10mm and 0.850mm. Fine powder with a particle size below 0.05mm will increase the dust of the finished product, and particles with a particle size above 1.00mm will slow down the water absorption rate of the finished product. According to the invention, the particle size distribution of the acrylate polymer should be as narrow as possible.

Superabsorbent resin is a kind of insoluble hydrophilic polymer. The resin has a uniform bridging structure inside. Generally, in order to improve the quality, such as improving the absorption rate, improving the colloid strength, improving the caking resistance, and liquid permeability The surface of the resin will be further bridged. This kind of surface crosslinking treatment uses a multifunctional crosslinking agent that can react with acid groups. At present, many patents have been published, such as: dispersing superabsorbent resin and crosslinking. The coupling agent is subjected to surface cross-linking treatment in an organic solvent (JP-A-56-131608, JP-A-57-44627, JP-A-58-42602, JP-A58-117222), and the cross-linked Agent and cross-linking agent solution are mixed into superabsorbent resin treatment (JP-A60-163956, JP-A-60-255814), after adding cross-linking agent, steam treatment (JP-A-1-113406), using organic solvent, Water and polyalcohol carry out surface treatment (JP-A-1-292004, U.S. Patent No. 6346569), although the method for using these surface treatments such as organic solution, water, ether (ether) compound (JP-A-2-153903) can Improve the absorption rate and increase the water absorption rate under pressure, but it will cause the adverse consequences of excessive reduction in holding power and reduce the performance of practical applications.

According to the present invention, the cross-linking agent that can react simultaneously during surface treatment can be a polyhydric alcohol such as: glycerol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, etc.; Amines such as: ethylenediamine, diethylenediamine, triethylenediamine; or compounds with two or more epoxy groups such as: sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, ethylene glycol Diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, diglycerol polyglycidyl ether, etc.; there are also alkylene carbonates such as: ethylene glycol carbonate, 4-methyl Base-1,3-dioxolane-2-one, 4,5-dimethyl-1,3-dioxolane-2-one, 4,4-dimethyl-1, 3-dioxolane-2-one, 4-ethyl-1,3-dioxolane-2-one, 1,3-dioxolane-2-one, 4, 6-Dimethyl-1,3-dioxan-2-one or 1,3-dioxepan-2-one, etc.

The above-mentioned surface crosslinking agents can be used alone or in combination of two or more. The appropriate additive amount of the crosslinking agent is between 0.001% and 10% by weight (based on the total solid content of the reactants), and the more appropriate amount is between 0.005% and 5% by weight. When the amount of the crosslinking agent additive is less than 0.001% by weight, the effect cannot be exhibited, and when the amount of the crosslinking agent is more than 10% by weight, the water absorption is too low and the performance of the resin is reduced.

The method of adding the surface cross-linking agent of the present invention during the coating process is based on the type of the surface cross-linking agent. An aqueous organic solvent solution is added. Hydrophilic organic solvents such as methanol, ethanol, propanol, isobutanol, acetone, methyl ether, ether, etc. are not particularly limited as long as they can form a solution, among which methanol and ethanol are preferred (US Patent No. 6849665).

In order to fully demonstrate the characteristic advantages of the present invention, the general formula used for the present invention having amino or hydroxyl compounds is:

X-R-Y (1)

In the formula; R represents an alkyl (Alkyl) compound with a carbon number of not less than 4 and a straight or branched chain;

X and Y are amino groups or hydroxyl groups.

As far as the present invention is concerned, the mixed aqueous solution of the compound satisfying the general formula (1) and the cross-linking compound is sprayed on the superabsorbent resin for cross-linking reaction, and then treated with hot air at a temperature of 120°C to 230°C to produce a The superabsorbent resin with slow absorption speed and high absorption ratio under relatively high pressure is the biggest technical feature of the present invention. The superabsorbent resin used to manufacture the above-mentioned steps is not particularly limited, as long as the superabsorbent resin produced by the method of the present invention can be applied to various types of hygienic, agricultural and food preservation products. Absorbents.

Compounds having amino or hydroxyl groups used in the present invention are, for example: 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,4 -Pentanediol, 1,5-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,4-butane Diamine, 2-amino-1-butanol, 2-amino-1-pentanol, 2-amino-1-hexanol, 2-amino-2-methyl-1-propanol, 2- Amino-3-methyl-1-butanol, 2-amino-4-methyl-1-pentanol and the like. The usage of this amine-containing or hydroxyl compound can be used alone or in combination of two or more. The amount used is between 0.005% and 3% by weight. When the amount of the additive containing amino group or hydroxyl compound is less than 0.001% by weight, the effect cannot be exhibited, and when the amount of the additive is more than 5% by weight, the water absorption is too low and the performance of the resin is reduced.

The method of the present invention for preparing a superabsorbent resin with a slow absorption rate is based on the surface of the superabsorbent resin prepared by a known method, and then further bridging (surface cross-linking reaction), that is, adding and coating with amine-containing or Hydroxyl compounds undergo surface cross-linking reaction on superabsorbent resin particles, and the addition of amino or hydroxyl compounds is as follows:

(a) After being mixed with the surface crosslinking aqueous solution, it is coated on the surface of the superabsorbent resin to carry out the surface crosslinking reaction;

(b) before adding the surface cross-linking agent to the surface of the super absorbent resin for surface cross-linking treatment; or

(c) After adding the surface cross-linking agent and then adding it to the super absorbent resin.

The powdery, water-insoluble, superabsorbent resin capable of absorbing water, urine and blood has slow absorption speed and high absorption rate under relatively high pressure. Its manufacturing method includes at least:

(a) Using a water-soluble unsaturated monomer containing acrylic acid (salt) and/or acrylamide (salt), the neutralization ratio is in the range of 45 to 85 mol%, and the concentration of the unsaturated monomer aqueous solution is in the range of 20 to The scope of 55% by weight carries out polymerization reaction;

(b) The gel body generated after the reaction is chopped, dried, pulverized and screened with hot air at a temperature ranging from 100°C to 180°C;

(c) subjecting the screened superabsorbent resin to a mixed aqueous solution of a crosslinking compound and an amino- or hydroxyl-containing compound for surface crosslinking coating; and

(d) Heat treatment at a temperature of 120°C to 230°C.

The above feature is the use of amino or hydroxyl compounds to carry out surface cross-linking polymerization with superabsorbent resin. When the surface cross-linking polymerization is completed, hydrophobic groups will be generated on the surface of superabsorbent resin to reduce the absorption rate. , and has the efficacy characteristics of higher absorption rate under high pressure.

As far as the present invention is concerned, the superabsorbent resin produced by the present invention has the characteristics of slow absorption rate and high absorption rate under high pressure, and the superabsorbent resin produced by the present invention The resin will be more suitable for various types of hygienic, agricultural and food-preserving water-absorbing articles.

In order to show the water absorption rate under pressure of the superabsorbent resin of the present invention, the holding power of the present invention is measured by the tea bag test method, and the average value is obtained after removing the highest value and the lowest value from five measurement results, and the 0.2g The superabsorbent resin was packed in a tea bag and soaked in 0.9% NaCl aqueous solution for 20 minutes, then the soaked tea bag was placed in a centrifuge (diameter 23 cm, rotating speed 1400 rpm) for three minutes and then weighed. The obtained value first subtracts the weight of the tea bag of the blank group not filled with superabsorbent resin (operate in the same procedure) and then divides it by the weight of the polymer to obtain the holding force value.

The water absorption rate under pressure of the superabsorbent resin of the present invention is measured by the pressure absorption weight (pressure load: 20g/cm ² and 49g/cm ² ), and the pressure absorption is based on page 7 of the specification of European Patent No. 0339461A The method described in ; that is, the initial weight of the super absorbent resin is placed in a cylinder with a sieve shading, and a pressure of 20g/cm ² and 49g/cm ² is applied to the powder, and then the cylinder is placed in the Let the superabsorbent resin absorb 0.9% sodium chloride aqueous solution for one hour on the absorbency demand tester, and then divide the measured water absorption weight by the weight of the superabsorbent resin to obtain the weight value under pressure.

The present invention is described in detail below with reference examples and examples; however, the scope of the present invention is not limited by these examples.

Reference example: (well-known technology in the art, superabsorbent resin production method)

1) Take 218.7g of 48% sodium hydroxide aqueous solution and slowly add it to a 500c.c conical flask with 270g of acrylic acid and 291.6g of water. The dropping ratio of sodium hydroxide/acrylic acid is in the range of 0.85 to 0.95. For 2 hours, and keep the temperature of the neutralization reaction system in the bottle within the range of 20°C to 40°C; at this time, an aqueous solution with a monomer concentration of 42% by weight is obtained, in which 70mol% (molar ratio) of acrylic acid is partially neutralized to become sodium acrylate .

2) Add 0.414g of N,N'-methylenebisacrylamide into the water-soluble unsaturated monomer solution, and keep the temperature at about 20°C.

3) Add 0.144g of hydrogen peroxide, 1.8g of sodium bisulfite and 1.8g of ammonium persulfate initiator to carry out polymerization reaction.

4) The gel body generated by the reaction is chopped with a cutting mill, and the gel body whose particle size is less than 2 mm in diameter is screened out.

5) After drying at 130° C. for 2 hours, sieve through a sieve with a fixed particle size of 0.1 mm to 0.85 mm to obtain a powdery superabsorbent resin. The measured retention force is 41.9g/g, the water absorption capacity under 20g/cm ² pressure is 6.5g/g, and the water absorption capacity under 49g/cm ² pressure is 6.2g/g.

Embodiment one:

Weigh 100 g of the superabsorbent resin prepared in the reference example, add 2.5 g of an aqueous solution mixed with ethylene glycol, 1,4-butanediol (manufactured by Taiwan Plastics Corporation) and methanol 1/1/0.5, and heat at 150°C Treat for 1 hour, and after cooling, high-performance superabsorbent resin can be obtained. The measured holding power is 31.9g/g, the water absorption capacity under 20g/ ^cm2 pressure is 28.7g/g, the water absorption rate under 49g/ ^cm2 pressure is 19.2g/g, and the ARI value is 8 minutes.

Embodiment two

Repeat Example 1, but heat treatment at 180° C. for 10 minutes, and the rest is the same as Example 1 to obtain a high-performance superabsorbent resin. The measured holding power is 32.7g/g, the water absorption capacity under 20g/ ^cm2 pressure is 28.1g/g, the water absorption rate under 49g/ ^cm2 pressure is 18.5g/g, and the ARI value is 9.5 minutes.

Embodiment three

Repeat Example 1, but use 1,4-butanediamine (manufactured by Fluka, trade name: 32790) instead of 1,4-butanediol, and the rest are the same as Example 1 to obtain a high-performance superabsorbent resin. The measured holding power is 32.5g/g, the water absorption capacity under 20g/ ^cm2 pressure is 28.9g/g, the water absorption rate under 49g/ ^cm2 pressure is 19.4g/g, and the ARI value is 8.4 minutes.

Embodiment Four

Repeat Example 3, but heat treatment at 190° C. for 10 minutes, and the rest are the same as Example 3 to obtain a high-performance superabsorbent resin. The measured retention force was 32.1g/g, the water absorption rate under 20g/ ^cm2 pressure was 29.4g/g, the water absorption rate under 49g/ ^cm2 pressure was 19.1g/g, and the ARI value was 9.6 minutes.

Embodiment five

Repeat Example 1, but use 2-amino-1-butanol (manufactured by Fluka Company, trade name: 7176) instead of 1,4-butanediol, and the rest are the same as Example 1 to obtain a high-performance superabsorbent resin. The measured holding power is 31.5g/g, the water absorption capacity under 20g/ ^cm2 pressure is 28.2g/g, the water absorption rate under 49g/ ^cm2 pressure is 18.3g/g, and the ARI value is 15.7 minutes.

Embodiment six

Repeat Example 1, but use 1,2-octanediol (manufactured by Sigma-Aldrich, trade name: 213705) instead of 1,4-butanediol, and the rest are the same as Example 1 to obtain a high-performance superabsorbent resin. The measured holding power is 31.1g/g, the water absorption capacity under 20g/ ^cm2 pressure is 29.5g/g, the water absorption rate under 49g/ ^cm2 pressure is 18.9g/g, and the ARI value is 23.5 minutes.

Embodiment seven

Repeat Example 1, but use ethylene glycol carbonate instead of ethylene glycol, and the rest are the same as Example 1 to obtain a high-performance superabsorbent resin. The measured holding power was 32.7g/g, the water absorption capacity under 20g/ ^cm2 pressure was 29.1g/g, the water absorption rate under 49g/ ^cm2 pressure was 19.4g/g, and the ARI value was 10.4 minutes.

Embodiment Eight

Repeat Example 6, but use ethylene glycol carbonate instead of ethylene glycol, and the rest are the same as Example 6 to obtain a high-performance superabsorbent resin. The measured holding power is 32.2g/g, the water absorption capacity under 20g/ ^cm2 pressure is 29.4g/g, the water absorption rate under 49g/ ^cm2 pressure is 19.5g/g, and the ARI value is 26.7 minutes.

Comparative example one

Repeat Example 1, but 1.5 g of the aqueous solution of 1/0.5 mixture of ethylene glycol and methanol, without adding 1,4-butanediol, and the rest are the same as Example 1 to obtain a high-performance superabsorbent resin. The measured holding power is 32.5g/g, the water absorption capacity under 20g/ ^cm2 pressure is 29.1g/g, the water absorption rate under 49g/ ^cm2 pressure is 19.4g/g, and the ARI value is 1.3 minutes.

Comparative example two

Repeat Comparative Example 1, 2.5 g of the aqueous solution mixed with ethylene glycol and methanol 1/0.5, and the rest are the same as Comparative Example 1 to obtain a high-performance superabsorbent resin. The measured holding power is 32.9g/g, the water absorption capacity under 20g/ ^cm2 pressure is 28.7g/g, the water absorption rate under 49g/ ^cm2 pressure is 19.8g/g, and the ARI value is 1.6 minutes.

Comparative example three

Repeat Comparative Example 2, but replace ethylene glycol with ethylene glycol carbonate, and the rest are the same as Comparative Example 2 to obtain a high-performance superabsorbent resin. The measured holding power is 32.1g/g, the water absorption capacity under 20g/ ^cm2 pressure is 29.4g/g, the water absorption rate under 49g/ ^cm2 pressure is 19.5g/g, and the ARI value is 1.1 minutes.

Claims (5)

1. A method of manufacturing a superabsorbent resin, comprising: (i) in the superabsorbent resin particles with internal crosslinking structure generated by the free radical polymerization reaction of the acid group-containing monomer aqueous solution; (ii) Adding 0.001 to 10% by weight of the total amount of the resin, and 0.001 to 5% by weight of the total amount of the resin, a solution of a compound having a hydroxyl group or an amino group mixed with water and the superabsorbent resin particles A manufacturing method characterized by surface cross-linking reaction coating treatment by remixing. 2. The method for manufacturing a superabsorbent resin according to claim 1, wherein the general formula of the compound having a hydroxyl group or an amino group is: X-R-Y (1) In the formula, R represents an alkyl compound with a carbon number of not less than 4 and a straight or branched chain; X and Y are amino groups or hydroxyl groups. 3. The method for producing a superabsorbent resin according to claim 1 or 2, wherein the compound having a hydroxyl group or an amino group is selected from the group consisting of 1,4-butanediol, 1,4-butanediamine, 2-amino - 1-butanol or 1,2-octanediol. 4. The method for producing a superabsorbent resin according to claim 1, wherein the surface cross-linking agent is selected from ethylene glycol of polyalcohol and ethylene glycol carbonate of alkylene carbonate. 5. The method for producing a superabsorbent resin according to claim 1, wherein the absorption rate index of the produced superabsorbent resin is at least 5 minutes.