KR20170085417A - Biodegradable and superabsorbent cured polyvinylalcohol resin and method for preparing the same - Google Patents

Abstract

The present invention relates to polyvinyl alcohol; And a crosslinking agent obtained by crosslinking polyvinyl alcohol; And a crosslinked polyvinyl alcohol resin. INDUSTRIAL APPLICABILITY The present invention can provide a crosslinked polyvinyl alcohol resin having water solubility and biodegradability, which has a low environmental burden due to disposal and has a high water absorption and absorption rate, and can provide a high quality water absorbent product to which the polyvinyl alcohol resin is applied. In addition, since it has biodegradability based on polyvinyl alcohol having no toxicity and water solubility, it is not only environmentally friendly but also can be used to lower production cost by using low cost polycarboxylic acid anhydride, thereby improving price competitiveness.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crosslinked polyvinyl alcohol resin which is biodegradable and highly absorbent and a method for producing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a superabsorbent biodegradable resin and a method for producing the same, and more particularly to a biodegradable and highly absorbent crosslinked polyvinyl alcohol resin and a method for producing the same.

High absorbency resin has high absorbency and water retention, and it is used as a wide range of materials from sanitary ware to agriculture, horticulture, distribution materials, civil engineering, architecture, medical, toy. Particularly in recent years, studies are underway to utilize water absorbent resin having proper gel property and adhesive property as a component material of various electronic devices.

In the synthesis of the superabsorbent resin, an acrylic acid resin or the like such as a crosslinked sodium polyacrylate generally purified from crude oil is used as a raw material, but when acrylic acid based is used for disposable diapers and the like, it is concerned that environmental problems are caused at the time of disposal . Recently, attempts have been made to use cellulose derivatives as biodegradable and excellent absorbent materials. In particular, the use of carboxymethylcellulose containing carboxylate in its structure has been studied. For example, a method of chemically crosslinking carboxymethyl cellulose, and a method of self-crosslinking using radiation crosslinking. However, in the above technology, there is a problem in production cost when using all of the cellulose derivatives as a starting material, and since the bond between the crosslinking moiety and carboxymethyl cellulose is an ether bond, it is chemically stable and has a problem from the viewpoint of biodegradability.

On the other hand, a method of synthesizing a superabsorbent resin in which cellulose, chitin, chitosan or the like is used as a raw material and in which the biodegradability, the absorbing power and the absorbing speed are comparable to those of conventional acrylate resins has been disclosed. However, The solubility was extremely low and it was effective only for some natural materials such as carboxymethylcellulose (CMC). However, since the solubility of the solvent is also low, a long time of dissolution and dispersion at a high temperature is required, and the yield of the resulting resin is low. A method of using succinic anhydride as a method of crosslinking a cellulose-based material with an ester bond showing high biodegradability rather than an ether bond has been disclosed. However, since the content of the sodium carboxylate salt contained in the obtainable absorbent material is small, There is a problem that can not be obtained only at a late crosslinked body.

Therefore, in order to replace the crosslinked sodium polyacrylate as a material that can be applied to absorbent products, development of a biodegradable, highly absorbent and environmentally friendly water absorbent resin based on polyvinyl alcohol having no toxicity and water solubility is required have.

An object of the present invention is to provide a crosslinked polyvinyl alcohol resin which is a biodegradable superabsorbent resin having water solubility and biodegradability and has a low environmental burden due to disposal and high absorption and absorption rate I have to.

In addition, since the water absorbent resin produced on the basis of polyvinyl alcohol having no toxicity and water solubility has biodegradability, the environmental burden upon disposal is small and the production cost is reduced by using a low cost polycarboxylic acid anhydride, .

According to one aspect of the present invention, there is provided a polyvinyl alcohol; And a crosslinking agent obtained by crosslinking the polyvinyl alcohol; A crosslinked polyvinyl alcohol resin is provided.

The molecular weight (Mw) of the polyvinyl alcohol may be 500 to 500,000.

The hydrolysis degree of the polyvinyl alcohol may be 50 to 100%.

The crosslinked polyvinyl alcohol resin may be an ester crosslinked three-dimensional crosslinked structure.

The crosslinking agent may be a polycarboxylic anhydride.

Wherein the crosslinking agent is 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA), 3,3 ', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride (DSDA), biphenyltetracarboxylic acid 2 anhydride (BPDA), Meso-butane-1,2,3,4-tetracarboxylic dianhydride, 4,4'-biphthalic anhydride (4,4 '-Biphthalic anhydride, 4,4' - (hexafluoroisopropylidene) diphthalic anhydride, and 4,4'-oxydiphthalic anhydride ( 4,4'-Oxydiphthalic Anhydride).

The crosslinked polyvinyl alcohol resin may include at least one selected from an acetyl group, a carboxylic acid group, an acrylic group and a urethane group substituted with polyvinyl alcohol.

The crosslinked polyvinyl alcohol resin may be highly absorbent.

The crosslinked polyvinyl alcohol resin may be biodegradable.

According to another aspect of the present invention, there is provided an absorbent material comprising the crosslinked polyvinyl alcohol resin.

According to another aspect of the present invention, there is provided an absorbent article comprising the absorbent material.

According to another aspect of the present invention, there is provided a process for producing a crosslinked polyvinyl alcohol, comprising: (a) preparing an crosslinked polyvinyl alcohol by ester crosslinking reaction of a crosslinking agent and a solvent; A method for producing a crosslinked polyvinyl alcohol resin is provided.

The reaction mass ratio of the polyvinyl alcohol and the crosslinking agent may be 99.9: 0.1 to 0.1: 99.9.

In step (a), a basic catalyst may be further included.

The basic catalyst may be 4-dimethylaminopyridine (DMAP).

The solvent may be polar organic solvents.

Wherein the polar organic solvent is selected from the group consisting of N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulphoxide, dimethylformamide, tetrabutyl fluoride Ammonium chloride (Tetra-n-butylammonium fluoride TBAF), and lithium chloride.

(A ') after the step (a), a neutralizing agent is added and neutralized; Can be performed.

The neutralizing agent may be at least one selected from compounds containing an amine group and compounds containing a hydroxy group.

Hydrogen bonding between the polyvinyl alcohols is promoted by the neutralization treatment to form interpenetrating hydrogel networks of polyvinyl alcohol.

INDUSTRIAL APPLICABILITY The present invention can provide a crosslinked polyvinyl alcohol resin which is a biodegradable superabsorbent resin having water solubility and biodegradability so that it has a low environmental burden due to disposal and has a high water absorption and absorption rate.

In addition, since it has biodegradability based on polyvinyl alcohol having no toxicity and water solubility, it is not only environmentally friendly but also can be used to lower production cost by using low cost polycarboxylic acid anhydride, thereby improving price competitiveness.

1 shows an anticipated schematic view of the crosslinked polyvinyl alcohol resin of the present invention.
2 is a photograph showing the phenomenon before and after swelling by a 0.9% NaCl aqueous solution of the superabsorbent resin of the present invention.
3 is a graph showing absorbency and yield according to the reaction mass ratio of polyvinyl alcohol and 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA).
4 is a graph showing absorbency and yield according to the molecular weight of polyvinyl alcohol.
5 is a graph showing absorbency and gain according to the degree of hydration of polyvinyl alcohol.
Figure 6 shows the FT-IR spectrum.
7 is a graph showing a differential scanning calorimetry (DSC) analysis graph.

The invention is capable of various modifications and may have various embodiments, and particular embodiments are exemplified and will be described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Also, when an element is referred to as being "formed" or "laminated" on another element, it may be directly attached or laminated to the front surface or one surface of the other element, It will be appreciated that other components may be present in the < / RTI >

The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, the crosslinked polyvinyl alcohol resin of the present invention will be described.

The present invention relates to polyvinyl alcohol; And a crosslinking agent obtained by crosslinking the polyvinyl alcohol; And a crosslinked polyvinyl alcohol resin.

The molecular weight (Mw) of the polyvinyl alcohol may be 500 to 500,000, preferably 500 to 100,000, more preferably 1,000 to 100,000.

The degree of hydrolysis may be from 50 to 100%, preferably from 60 to 100%, more preferably from 70 to 99%.

The crosslinked polyvinyl alcohol resin may be an ester crosslinked three-dimensional crosslinked structure.

The cross-linking agent may be polycarboxylic acid anhydride, preferably 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA), 3,3 ', 4,4'-diphenylsulfonetetracarboxylic acid Acid dianhydride (DSDA), biphenyltetracarboxylic dianhydride (BPDA), Meso-butane-1,2,3,4-tetracarboxylic dianhydride, meso-butane-1,2,3,4-tetracarboxylic dianhydride, 4,4'-biphthalic anhydride, 4,4 '- (hexafluoroisopyridine) diphthalic anhydride, and 4,4'- (Hexafluoroisopropylidene) diphthalic anhydride, 4'-oxydiphthalic anhydride, and the like.

The crosslinked polyvinyl alcohol resin may include an acetyl group, a carboxylic acid group, an acrylic group, a urethane group, and the like substituted with a polyalcohol.

The crosslinked polyvinyl alcohol resin may be highly absorbent and may be biodegradable.

An absorbent material comprising the crosslinked polyvinyl alcohol resin of the present invention is provided.

An absorbent article comprising the absorbent material of the present invention is provided.

Hereinafter, a method for producing a crosslinked polyvinyl alcohol resin of the present invention will be described.

The polyvinyl alcohol, the cross-linking agent and the solvent are subjected to an ester cross-linking reaction to prepare cross-linked polyvinyl alcohol (step a).

The reaction product obtained by the ester cross-linking reaction is precipitated in an organic solvent such as methanol or acetone, and is neutralized with a basic aqueous solution. By this neutralization reaction, a carboxyl group is converted into a carboxylate, and a crosslinked polyvinyl alcohol resin having an ester crosslinked three-dimensional crosslinked structure serving as a water-retaining property can be obtained.

In step a, the intermolecular ester linkage by the cross-linking agent can generally proceed in two steps.

First, a cyclic acid anhydride intermediate may be formed by an acid anhydride of one of the polycarboxylic acid anhydride molecules which is a crosslinking agent. Next, a reaction between the acid anhydride intermediate and the hydroxyl group takes place to form the ester. At this time, a basic catalyst may be further added so that the dehydration reaction can smoothly proceed as a crosslinking agent.

The reaction mass ratio of the polyvinyl alcohol and the crosslinking agent may be 99.9: 0.1 to 0.1: 99.9, preferably 99: 1 to 1:99, more preferably 90: 1 to 1:90.

In step (a), a basic catalyst may be further included. As the basic catalyst, a nucleophilic acylation catalyst generally used in an organic synthesis reaction may be used. Preferably, 4-dimethylaminopyridine ( 4-dimethylaminopyridine, DMAP) can be used. However, the scope of the present invention is not limited thereto.

The solvent can be a polar organic solvent and is preferably a solvent such as N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulphoxide, Dimethylformamide, tetra-n-butylammonium fluoride (TBAF), or the like, and a small amount of lithium chloride may be used to increase solubility.

(A ') after the step (a), a neutralizing agent is added and neutralized; Can be performed.

The neutralizing agent may be a compound containing an amine group and a compound containing a hydroxyl group, and more preferably, sodium hydroxide may be used.

The neutralizing agent partially neutralizes the carboxyl group and the neutralization is carried out by neutralizing the acidic monomer with an optional base such as a monovalent inorganic base such as M + [OH-] x where M is a cationic moiety selected from sodium, potassium, And x has a value that provides a neutralized salt). In addition, non-metal hydroxides such as ammonium hydroxide, as well as organic amines including primary amines such as alkyl amines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine and the like, / RTI > and / or an organic compound containing a hydroxyl (OH) group functional group can be used.

By the neutralization reaction, the carboxyl group is converted into the carboxylic acid salt, and a biodegradable superabsorbent resin having an ester crosslinked three-dimensionally crosslinked structure serving as a water-retaining property and a carboxylate salt serving as an absorbing property can be obtained.

[Example]

Hereinafter, preferred embodiments of the present invention will be described. However, this is for illustrative purposes only, and thus the scope of the present invention is not limited thereto.

Example  One

1) Preparation of cross-linked polyvinyl alcohol resin

30 g of N-methyl-2-pyrrolidone (NMP) and 40 g of polyvinyl alcohol (PVA, molecular weight (Mw) = 44,000, degree of hydration (Hs) = 30 g) were placed in a 500 ml glass vessel, which had been charged with nitrogen, 72%) was added and nitrogen was continuously added to prepare a mixture.

The mixture was heated to 60 DEG C and sufficiently stirred for about 1 hour to obtain 1 g of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) as a polycarboxylic acid and 1 g of dimethyaminopyridine (DMAP) as a basic catalyst And polymerization was carried out for 6 hours. After cooling the temperature to room temperature, sodium hydroxide (NaOH) was injected in an appropriate amount to neutralize the reaction product to prepare a brown gel resin. The prepared gel resin was sufficiently washed with acetone to prepare a particulate polymer. The polymer was evenly spread on a stainless steel tray and dried in a hot air oven at 80 ° C for 15 hours to prepare a crosslinked polyvinyl alcohol resin. The obtained resin was pulverized using a pulverizer and classified with a standard mesh of ASTM standard to obtain 4 g of a crosslinked polyvinyl alcohol resin having a particle size of 300 to 600 mu m.

2) Measurement of maintenance ability

0.2 ml of the crosslinked polyvinyl alcohol resin on the particle was added to a dried tea bag in a predetermined amount, and then immersed in a beaker containing an aqueous NaCl solution for 30 minutes. . Then, centrifugation was performed for 3 minutes with a centrifuge (300 gravity) to completely remove the moisture adhering to the surface. The swelling ratio was calculated according to Equation 1 shown below.

(SR) = (Wt - W0) / W0

Wt = weight of swollen SAP in 0.9 wt% NaCl aqueous solution for 30 minutes

W0 = Weight of the first SAP loaded

The swelling ratio of the crosslinked polyvinyl alcohol resin to 0.9% NaCl aqueous solution measured by this method was 9.

Example  2

Except that 2 g of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) was added instead of 1 g of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) A biodegradable superabsorbent resin was prepared.

The weight of the resin thus prepared was 5 g, and the swelling ratio for an aqueous 0.9% NaCl solution was 8.

Example  3

Except that 3 g of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) was added instead of 1 g of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) A biodegradable superabsorbent resin was prepared.

The weight of the resin thus prepared was 5 g, and the swelling ratio for an aqueous 0.9% NaCl solution was 8.

Example  4

Except that 5 g of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) was added instead of 1 g of 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) A biodegradable superabsorbent resin was prepared.

The weight of the resin thus prepared was 4 g, and the swelling ratio of the aqueous solution of 0.9% NaCl was 6.

Table 1 summarizes the maintenance capacity and yield according to the mass ratio of the polyvinyl alcohol and 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) of the resin prepared according to Examples 1 to 4 will be.

division Example 1 Example 2 Example 3 Example 4 PVA: BTCA reaction mass ratio 3: 1 3: 2 3: 3 3: 5 Ability to maintain 9 8 8 6 Yield (g) 4 5 5 4

Example  5

A biodegradable superabsorbent resin was prepared in the same manner as in Example 1, except that polyvinyl alcohol (PVA) having a molecular weight of 10,000 was used instead of polyvinyl alcohol (PVA) having a molecular weight (Mw) of 44,000.

The weight of the resin thus prepared was 4 g, and the swelling ratio for an aqueous 0.9% NaCl solution was 7.

Example  6

A biodegradable superabsorbent resin was prepared in the same manner as in Example 1, except that polyvinyl alcohol (PVA) having a molecular weight of 31,000 was used instead of polyvinyl alcohol (PVA) having a molecular weight (Mw) of 44,000.

The weight of the resin thus prepared was 5 g, and the swelling ratio for a 0.9% NaCl aqueous solution was 7.

Example  7

A biodegradable superabsorbent resin was prepared in the same manner as in Example 1, except that polyvinyl alcohol (PVA) having a molecular weight of 85,000 was used instead of polyvinyl alcohol (PVA) having a molecular weight (Mw) of 44,000.

The weight of the resin thus prepared was 4 g, and the swelling ratio to an aqueous 0.9% NaCl solution was 8.

Table 2 summarizes the maintenance capacity and yield according to the molecular weight of the polyvinyl alcohol (PVA) of the resin prepared according to Example 1 and Examples 5 to 7.

division Example 5 Example 6 Example 1 Example 7 PVA molecular weight 10,000 31,000 44,000 85,000 Ability to maintain 7 7 9 8
Yield (g) 4 5 5 4

Example  8

Except that polyvinyl alcohol (PVA) having a hydration degree (Hs) of 80% was used in place of polyvinyl alcohol (PVA) having a hydration degree (Hs) of 72%, a biodegradable superabsorbent resin .

The weight of the resin thus prepared was 4 g, and the swelling ratio for an aqueous 0.9% NaCl solution was 7.

Example  9

Except that polyvinyl alcohol (PVA) having a degree of hydration (Hs) of 88% was used in place of polyvinyl alcohol (PVA) having a hydration degree (Hs) of 72%, a biodegradable superabsorbent resin .

The weight of the resin thus prepared was 4 g, and the swelling ratio to an aqueous 0.9% NaCl solution was 8.

Example  10

Except that polyvinyl alcohol (PVA) having a degree of hydration (Hs) of 98% was used in place of polyvinyl alcohol (PVA) having a degree of hydration (Hs) of 72%, the biodegradable superabsorbent resin .

The weight of the resin thus prepared was 5 g, and the swelling ratio for a 0.9% NaCl aqueous solution was 7.

Example  11

Except that polyvinyl alcohol (PVA) having a degree of hydration (Hs) of 99% was used in place of polyvinyl alcohol (PVA) having a hydration degree (Hs) of 72%, a biodegradable superabsorbent resin .

The weight of the resin thus prepared was 4 g, and the swelling ratio to an aqueous 0.9% NaCl solution was 8.

Table 3 summarizes the maintenance capacity and yield of the resin prepared according to Example 1 and Examples 8 to 11 according to polyvinyl alcohol (PVA) degree of hydration.

division Example 1 Example 8 Example 9 Example 10 Example 11 The degree of hydration (Hs) 72 80 88 98 99 Ability to maintain 9 7 8 7 8 Yield (g) 5 4 4 5 4

[Test Example]

Test Example 1: Crosslinked polyvinyl alcohol resin image before and after swelling

Fig. 2 shows an image before and after the absorption of 0.9% NaCl aqueous solution of the copolymer prepared according to Example 1. Fig.

Referring to FIG. 2, it was visually confirmed that the copolymer of the present invention swelled by absorbing 0.9% NaCl aqueous solution. Therefore, it is judged that the biodegradable superabsorbent resin of the present invention has excellent water absorption ability.

Test Example  2: polyvinyl alcohol and 1,2,3,4- Butanetetracarboxylic acid 2 anhydride (BTCA)  Analysis of maintenance capacity and yield graphs according to reaction mass ratio

Fig. 3 is a graph showing the maintenance capacity and yield of the resin prepared according to Examples 1 to 4. Fig.

Referring to FIG. 3, when the reaction mass ratio of poly (vinyl alcohol) and 1,2,3,4-butane tetracarboxylic acid dianhydride (BTCA) was 3: 1, Therefore, in order to obtain a biodegradable superabsorbent resin having excellent maintenance ability and yield, it is necessary to react polyvinyl alcohol (PVA) with 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) at a proper mass ratio .

Test Example 3: Analysis of the maintenance capacity and yield according to the molecular weight of polyvinyl alcohol

Fig. 4 is a graph showing the maintenance capacity and yield of the resin prepared according to Example 1 and Examples 5 to 7. Fig.

Referring to FIG. 4, when the molecular weight of the polyvinyl alcohol was 44,000, it was confirmed that the maintenance ability and the yield were the highest. Therefore, it is considered that the molecular weight of polyvinyl alcohol is 44,000 in order to obtain a biodegradable superabsorbent resin having excellent maintenance ability and yield.

Test Example  4: of polyvinyl alcohol The degree of hydration (Hs)  And Yield  Graph Analysis

Fig. 5 is a graph showing the maintenance capacity and yield of the resin prepared according to Example 1 and Examples 8 to 11. Fig.

Referring to FIG. 4, when the degree of hydration of polyvinyl alcohol was 72%, it was confirmed that the maintenance ability and yield were the highest. Therefore, the hydration degree (Hs) of polyvinyl alcohol is 72% in order to obtain a biodegradable superabsorbent resin having excellent water retention capacity and yield.

Test Example 5: FT-IR spectrum analysis

6 shows the FT-IR spectrum of polyvinyl alcohol and crosslinked polyvinyl alcohol.

Referring to FIG. 6, an ester crosslinking reaction between a hydroxyl group (OH) of polyvinyl alcohol (PVA) and 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) is carried out between polyvinyl alcohol molecules Ester bridging. At the same time, intramolecular bond formation due to the hydroxyl group interaction between polyvinyl alcohol backbone chains was formed. Thus, all the polymers produced in the polymerization system were subjected to interfacial polymer networks , IPN) were formed in a complex manner.

Test Example  6: Differential Scanning Calorimetry, DSC ) Graph analysis

7 is a DSC graph of polyvinyl alcohol and cross-linked polyvinyl alcohol.

DSC analysis was carried out using a DSC Q10 (model name) manufactured by TA Instrument Korea. The sample weight was 7 to 8 mg, the measurement temperature was 40 to 300 ° C, the heating rate was 10 ° C / min and nitrogen gas atmosphere.

Referring to FIG. 7, the crosslinked polyvinyl alcohol resin of the present invention is obtained by ester crosslinking reaction between the hydroxyl group of polyvinyl alcohol (PVA) and 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA) It was confirmed that ester crosslinking was formed between the polyvinyl alcohol molecules and at the same time intramolecular bonding was formed due to the hydroxyl group (OH) interaction between the main chains of the polyvinyl alcohol, so that the total polymer It was confirmed that interpenetrating hydrogel networks (IPN) were formed in a complex manner.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is possible.

Claims (20)

Polyvinyl alcohol; And
A crosslinking agent obtained by crosslinking the polyvinyl alcohol; To
Wherein the crosslinked polyvinyl alcohol resin is a crosslinked polyvinyl alcohol resin. The method according to claim 1,
Wherein the polyvinyl alcohol has a molecular weight (Mw) of 500 to 500,000. The method according to claim 1,
Wherein the polyvinyl alcohol has a degree of hydrolysis of 50 to 100%. The method of claim 1, wherein
Wherein the crosslinked polyvinyl alcohol resin is an ester crosslinked three-dimensional crosslinked structure. The method according to claim 1,
Wherein the crosslinking agent is a polycarboxylic acid anhydride. 6. The method of claim 5,
Wherein the crosslinking agent is 1,2,3,4-butanetetracarboxylic acid dianhydride (BTCA), 3,3 ', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride (DSDA), biphenyltetracarboxylic acid 2 anhydride (BPDA), Meso-butane-1,2,3,4-tetracarboxylic dianhydride, 4,4'-biphthalic anhydride (4,4 '-Biphthalic anhydride, 4,4' - (hexafluoroisopropylidene) diphthalic anhydride, and 4,4'-oxydiphthalic anhydride ( 4,4'-oxydiphthalic anhydride). The cross-linked polyvinyl alcohol resin according to claim 1, The method according to claim 1,
Wherein the crosslinked polyvinyl alcohol resin comprises at least one selected from an acetyl group, a carboxylic acid group, an acrylic group and a urethane group substituted with polyvinyl alcohol. The method according to claim 1,
Wherein the crosslinked polyvinyl alcohol resin is highly water-absorbing. 9. The method of claim 8,
Wherein the cross-linked polyvinyl alcohol resin is biodegradable. An absorbent material comprising the crosslinked polyvinyl alcohol resin of claim 1. An absorbent article comprising the absorbent material of claim 10. (A) preparing a crosslinked polyvinyl alcohol by ester crosslinking reaction of polyvinyl alcohol, a crosslinking agent and a solvent; ≪ / RTI > 13. The method of claim 12,
Wherein the mass ratio of the polyvinyl alcohol and the crosslinking agent is 99.9: 0.1 to 0.1: 99.9. 13. The method of claim 12,
A process for producing a crosslinked polyvinyl alcohol resin, characterized in that, in step (a), a basic catalyst is further included. 15. The method of claim 14,
Wherein the basic catalyst is 4-dimethylaminopyridine (DMAP). ≪ RTI ID = 0.0 > 11. < / RTI > 13. The method of claim 12,
Wherein the solvent is a polar organic solvent. 17. The method of claim 16,
Wherein the polar organic solvent is selected from the group consisting of N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulphoxide, dimethylformamide, tetrabutyl fluoride Ammonium chloride (Tetra-n-butylammonium. Fluoride TBAF), and lithium chloride. 13. The method of claim 12,
(A ') after the step (a), a neutralizing agent is added and neutralized; Wherein the polyvinyl alcohol resin is a polyvinyl alcohol. 19. The method of claim 18,
Wherein the neutralizing agent is at least one compound selected from a compound containing an amine group and a compound containing a hydroxy group. 19. The method of claim 18,
Wherein hydrogen bonding between the polyvinyl alcohols is promoted by the neutralization treatment to form interpenetrating hydrogel networks of polyvinyl alcohol. ≪ RTI ID = 0.0 > 8. < / RTI >

Images