KR20230013711A - Preparation method of natural biodegradable highly absorbent composite and use thereof - Google Patents

Abstract

The present invention relates to a manufacturing method of a natural biodegradable super absorber and uses thereof. The absorption capacity of the absorber manufactured according to the manufacturing method of the present invention is at a level sufficient to meet the standard value, and as a result of biodegradation experiments, since the absorber has more significant biodegradation effects than those of conventional synthetic absorbents, the absorber can be usefully used in sanitary products for the purpose of absorbing moisture.

Description

Preparation method of natural biodegradable highly absorbent composite and use thereof {Preparation method of natural biodegradable highly absorbent composite and use thereof}

The present invention relates to a method for preparing a natural biodegradable super absorbent and a use thereof.

Superabsorbent polymer (SAP) refers to a cross-linked polymer capable of absorbing a large amount of liquid, swelling to form a hydrogel, and retaining the absorbed liquid. Representative types of synthetic polymer absorbers include crosslinked hydroalkyl (meth)acrylic acid, N-vinylpyrrolidone, ethyl oxide, acrylamide, (meth)acrylic acid, poly(vinyl alcohol), and crosslinked poly(acrylic acid) (PAA ) dominates the market.

There are various sanitary products such as women's sanitary napkins, diapers for infants and children, and most of them use petrochemical-based polymer absorbers that are harmful to the human body. Since sanitary products made of the petrochemical-based polymer absorber cannot be biodegraded after use, it causes various serious environmental and economic problems in the landfill or incineration process when discarded. / It has been very active both internally and externally, but the performance of the product is not only very low in water retention and absorbency under pressure compared to existing chemical products, but also causes heat, skin soreness, and itching caused by harmful substances.

On the other hand, chitin is the second most abundant polymer after cellulose in the natural environment, and is a polymer in which N-acetyl-glucosamine [poly-b-(1-4)-N-acetyl-D-glucosamine] is continuously bonded. to be. It is also the main component of the shells of crustaceans such as crayfish, crabs, and shrimps, the exoskeleton of insects such as scarabs, cicadas, and grasshoppers, the skeletons of mollusks such as squid, and the cell walls of fungi such as molds, yeasts, and mushrooms. Since chitin is synthesized in various living organisms, it is also considered a biopolymer. It has chemical properties that are insoluble in water and is a water-soluble material called Chitosan that can be applied for various purposes through a chemical process called deacetylation. Transformed.

Chitin has a structure similar to that of cellulose in which 2-acetamino-2-deoxy-D-glucose is β-(1,4) bonded, and the hydroxyl group at the C-2 position is substituted with an acetamino group, and C3-OH... The intermolecular bonds of C5 and NH… O=C and C6-OH... O=C is stabilized by intermolecular hydrogen bonds. Depending on the arrangement of molecular chains in the crystal structure, there are three stereoisomers of α-, β-, and γ-. α-chitin is the most dense form because two chains are stacked antiparallel to each other, and β-chitin is a form in which chains are arranged parallel to each other, and C ₃ -OH ^... O ₅ between the same chains is different from each other. Interchain -NH and -CO groups form hydrogen bonds, but it is less dense than α-chitin. γ-chitin has a downward arrangement of one unit chain for every two pyranose units. In nature, α-chitin is most widely distributed, and it is especially contained in the epidermis of arthropods. β-Chitin exists in a crystalline hydrate state and is a poorly stable material that is poorly arranged so that water can easily permeate between the chains of the crystal lattice, and is most abundant in the bones of cuttlefish. α-chitin is present in the cysts of arthropods, mushrooms and Entamoea , and β-chitin can be obtained from the bones of Loligo . Finally, γ-chitin is present in the cocoons of beetles and the stomach walls of Loligo . The structure of this γ-chitin consists of two antiparallel chains and one parallel chain.

Chitin is used as an ingredient in fertilizers to increase crop yields. Fertilizers containing chitin are organic materials, have low toxicity and are known to increase yield. It is also known to help harvest by increasing the activity of soil microorganisms and enzymes when treated with chitin-containing fertilizer. Crabs, shrimp, etc. have been materials from which chitin can be obtained from the past, and chitin obtained from them has long been used as a variety of food additives. Finely powdered chitin is used as a food additive and improves the flavor of food. In addition, it is added to food to function as an emulsifier. Chitin is also used in medicine and is known to reduce cholesterol when consumed by humans. It is also used as a material for suture thread used in surgical operations. Chitin is known to aid in the healing process of wounds and is naturally biodegradable.

On the other hand, as an absorber-related technology, Korean Patent Publication No. 2018-0028244 discloses a method for manufacturing a natural polymer absorber capable of absorbing moisture, and Korean Patent No. 2052113 discloses a red algae extract and a polymer of water-soluble chitin as active ingredients. A water absorbent with improved absorption and antibacterial activity and a method for preparing the same have been disclosed, but the method for preparing the natural biodegradable super absorbent of the present invention and its use have not yet been disclosed.

The present invention has been derived from the above needs, and the present invention provides a method for producing a natural biodegradable super absorbent and its use, and the absorbent produced according to the manufacturing method of the present invention has a sufficient level to meet the standard value. And, as a result of the biodegradation experiment, the present invention was completed by confirming that there is a significant biodegradation effect than the conventional synthetic absorber.

In order to achieve the above object, the present invention (1) based on 100 parts by weight of chitin, after adding 100 to 500 parts by weight of water, 50 to 150 parts by weight of a compound containing a phosphoric acid group and 100 to 300 parts by weight of a urea-based compound , reacting at 20 to 40 ° C. for 3 to 9 hours, washing and first drying;

(2) heat-treating the chitin dried in step (1) at 140-180° C. for 10-100 minutes, then washing the heat-treated chitin with a caustic soda solution to make it gel, and washing with water to swell;

(3) fibrillating chitin using a high-speed grinder, homogenizer, or super mass collidor so that the chitin swollen in step (2) has a width of 3 nm to 3 μm;

(4) secondarily drying the chitin fibrillated in step (3) at 30 to 100° C.; and

(5) preparing a powder having a diameter of 10 to 3,000 μm by pulverizing the secondarily dried chitin fibrils in step (4);

In addition, the present invention provides a sanitary product comprising the natural biodegradable super absorbent produced by the manufacturing method of the present invention.

The present invention relates to a method for producing a natural biodegradable super absorbent and its use, and the absorbent produced according to the manufacturing method of the present invention has a sufficient level of absorption to meet the standard value, and as a result of biodegradation experiments, a remarkable biodegradation effect than conventional synthetic absorbents. there is

1 is a comparative photograph of the high absorbents of Example 2 and Comparative Example 1 of the present invention before biodegradation (Day 0) and Day 7.

The present invention (1) based on 100 parts by weight of chitin, after adding 100 to 500 parts by weight of water, 50 to 150 parts by weight of a compound containing a phosphoric acid group, and 100 to 300 parts by weight of a urea-based compound, at 20 to 40 ℃ 3 Reacting for ~9 hours, washing and primary drying;

(2) heat-treating the chitin dried in step (1) at 140-180° C. for 10-100 minutes, then washing the heat-treated chitin with a caustic soda solution to make it gel, and washing with water to swell;

(3) fibrillating chitin using a high-speed grinder, homogenizer, or super mass collidor so that the chitin swollen in step (2) has a width of 3 nm to 3 μm;

(4) secondarily drying the chitin fibrillated in step (3) at 30 to 100° C.; and

(5) preparing a powder having a diameter of 10 to 3,000 μm by pulverizing the secondarily dried chitin fibrils in step (4);

The chitin is an N-acetylglucosamine [poly-b-(1-4)-N-acetyl-D-glucosamine] polymer, preferably α-chitin or β-chitin derived from crustaceans such as crab shells, and more Preferred is β-chitin, but is not limited thereto.

In step (1), the compound containing a phosphoric acid group is preferably any one selected from monobasic ammonium phosphate, dibasic ammonium phosphate ((NH ₄ ) ₂ HPO ₄ ) and sodium dihydrogen phosphate, more preferably Is monobasic ammonium phosphate, but is not limited thereto.

In the step (1), the urea-based compound is preferably any one selected from urea, thio urea, and dimethyl urea, and more preferably urea, but is not limited thereto.

Immediately before fibrillation in step (3), CMC (carboxy methyl cellulose), citric acid, konjac, alginic acid, carrageenan, pentane, cyclopentane, hexane, cyclohexane ( At least one selected from among cyclohexane, heptane, cycloheptane, butanol, and isobutanol may be added, and the width of the fibril in step (3) is 3 to 100 nm on average. It is characterized by

Between steps (3) and (4), with respect to 100 parts by weight of the fibrillated chitin obtained in step (3), any one selected from oxidized starch, cationic starch, phosphate starch, carrageenan, konjac, and alginic acid It is preferable to further include, but is not limited thereto.

In the present invention, 'cationic starch' can be prepared by treating corn starch, potato starch, tapioca starch, wheat starch, sweet potato starch, etc. with a cationizing agent, and is a conventional method in the art, for example, the method described in US Patent 4127563. can be obtained according to A cationizing agent refers to a substance in which one end of a molecule has a reactive group capable of bonding with a hydroxyl group on a starch molecule and the other end has a cationic group, such as derivatives containing a tertiary amino group and a quaternary ammonium ether group. , and quaternary ammonium-based protonating agents such as 3-chloro-2-hydroxytrimethylammonium chloride and 2,3-epoxypropyltrimethylammonium chloride are preferred.

Between steps (3) and (4), with respect to 100 parts by weight of the fibrillated chitin obtained in step (3), epichlorohydrin, glyoxal and maleic acid It is preferable to further include, but is not limited thereto.

Secondary drying in the manufacturing method of the present invention is drying by heat treatment; Solvent drying by adding any one organic solvent selected from methanol, ethanol, isopropanol, butanol, acetone and toluene; freeze drying; and vacuum drying; It is preferable to dry any one selected from, but is not limited thereto.

In addition, it relates to a sanitary product comprising a natural biodegradable super absorbent produced by the manufacturing method of the present invention.

The sanitary product is preferably any one selected from diapers for infants, diapers for adults, panty liners, sanitary napkins, and tampons, but is not limited thereto.

Hereinafter, the present invention will be described in more detail using examples. These examples are only for explaining the present invention in more detail, and it is obvious to those skilled in the art that the scope of the present invention is not limited thereto.

Example 1

(1) Immerse 100 g of β-chitin grains with a diameter of 2 to 5 mm in 250 g of distilled water solution in which 75 g of ammonium monophosphate and 200 g of urea are dissolved, react at 25 ° C for 6 hours, and remove the β- chitin grains. and dried at 30°C.

(2) After treating the dried β-chitin in step (1) at 150° C. for 60 minutes, it was washed with a caustic soda solution, and the washed β-chitin was washed again with water to prepare a swollen gel.

(3) Carboxymethyl cellulose (CMC) was added to the swollen β-chitin of step (2) in an amount of 3% by weight, and pulverized using a supermass colloider so that the width of β-chitin was 1 μm or less on average. and fibrillated.

(4) After step (3), the obtained β-chitin fibrils were dried at 60°C.

(5) After step (4), the dried β-chitin fibrils from which moisture was removed were pulverized to prepare a biodegradable superabsorbent in powder form having a diameter of 10 to 1,000 μm.

Example 2

In step (3) of Example 1, the rest of the steps are the same as in Example 1 except that CMC was not added and chitin was pulverized and fibrillated to an average width of 200 nm using a supermass colloider. As a method, a biodegradable super absorbent in the form of a powder having a size of 10 to 1,000 μm was prepared.

Example 3

In step (3) of Example 1, except for fibrillation by adding 3% by weight of citric acid instead of CMC, the rest of the steps are the same as in Example 1, and the biodegradable superabsorbent in powder form with a size of 10 to 1,000 μm was manufactured.

Example 4

In step (4) of Example 1, after adding 20% by weight of cationic starch (corn starch with a quaternary ammonium substitution degree of 0.9) to the chitin fibrils obtained in step (3), Except for drying at 60 ° C., the remaining steps were prepared in the same manner as in Example 1 to prepare a biodegradable super absorbent in the form of a powder having a size of 10 to 1,000 μm.

Example 5

In step (3) of Example 1, chitin fibrils were pulverized and fibrillated to an average width of 200 nm using a supermass colloider without adding CMC, and in step (4), chitin fibrils were 98 The remaining steps are the same as in Example 1, except that chitin fibrils are dried by slowly adding methanol at 500 revolutions per minute in methanol at 10 to 1,000 μm to obtain a powdery biodegradable superabsorbent. manufactured.

Example 6

In step (3) of Example 1, except for fibrillation by adding 5% by weight of pentane instead of CMC, the remaining steps are the same as in Example 1, and the biodegradable superabsorbent in powder form having a size of 10 to 1,000 μm was manufactured.

Comparative Example 1

A synthetic superabsorbent polymer (SAP) collected by separating and collecting oversized pant-type diapers of company Y on the market was used.

Comparative Example 2

DS228 X2 synthetic super absorbent (Danson Technology, China) was purchased and used.

Experimental Example 1. Comparative test of absorption capacity

The super absorbent was placed in a filter cloth, immersed in saline for 30 minutes, and dehydrated using centrifugal force together with the filter cloth, and then the weight (g) of the super absorbent was measured.

The ability of Examples 1 to 6 and Comparative Examples 1 and 2 to absorb saline Weight of initial absorber (g) after saline absorption
Weight of absorber (%) Water absorption rate of absorber (%) Example 1 1.0 18.4 1,740 Example 2 1.0 20.6 1,960 Example 3 1.0 15.8 1,480 Example 4 1.0 21.2 2020 Example 5 1.0 17.3 1,630 Example 6 1.0 16.8 1,580 Comparative Example 1 1.0 24.1 2,310 Comparative Example 2 1.0 20.7 1,970

In Table 1, the absorption rate of the absorbent was calculated as (weight of the absorbent after saline absorption - weight of the initial absorbent) × 100.

As a result, as shown in Table 1, the absorption rate (%) of the absorbers of Examples 1 to 6 of the present invention was found to be 1,480 to 2,020%, and the commercially available synthetic super absorbents of Comparative Examples 1 and 2 were 1,970 to 1,970 2,310% appeared. In general, in the case of a high absorbent material having an absorption rate (%) of 1,000% or more, it is known that there is no problem in using it in the production of products such as commercial diapers. Therefore, it can be seen that the natural superabsorbent has a slightly lower saline absorption rate than the synthetic superabsorbent, but is sufficient for use as an absorbent (Table 1).

In the case of natural superabsorbents, biodegradation at room temperature can solve the problem of microplastics, and various chemical substances (certification standard EL324:2017 by the Ministry of Environment, Annex D. List of allergens and carcinogens) that can be included in synthetic superabsorbents are fundamentally included. It has the advantage of not being.

Experimental Example 2. Comparison of changes in mass due to biodegradation of absorbers

Take 1g each of the synthetic superabsorbent (synthetic SAP; Comparative Example 1) and the natural superabsorbent (Bio SAP; Example 2) of the present invention, sufficiently absorb water, and place it in an oven at 30 ° C for 30 days to obtain the weight of biodegradation. Changes were measured. To measure the initial dry weight of the super absorbent, the super absorbent was washed using filter paper, dried in an oven at 100° C., and then the mass was measured.

As a result, the synthetic SAP had a water content of 9.88% and a dry weight of 0.912g (day 0), and the bio-SAP according to the present invention had a water content of 13.6% and a dry weight of 0.862g. After 7 days, 13 days, 20 days, and 30 days, each superabsorbent was washed with filter paper, dried, and weighed.

The values measured on the 7th to 30th days are shown in Table 2, as the amount remaining after biodegradation was measured by removing low-molecular-weight substances by biodegradation. It can be seen that the bio-SAP, which is a natural super absorbent, is biodegraded at room temperature and rapidly and continuously decreases in weight. .

That is, the natural superabsorbent of the present invention has a slightly low saline absorption rate, but is biodegraded at room temperature and turns yellow after 7 days (FIG. 1), and is almost completely decomposed within 3 weeks and the mass is reduced, but the synthetic superabsorbent confirmed that there was no change in its shape or mass (Table 2).

Day 0 Day 7 Day 13 Day 20 Day 30 Synthetic SAP, g 0.912 0.684 0.635 0.635 0.621 Synthetic SAP, % 100.0 75.2 69.5 69.5 68.1 Bio SAP, g
(Natural Super Absorber) 0.864 0.438 0.152 0.152 0.082 Bio SAP, %
(Natural Super Absorber) 100.0 50.7 17.6 17.6 9.5

Claims (11)

(1) Based on 100 parts by weight of chitin, after adding 100 to 500 parts by weight of water, 50 to 150 parts by weight of a compound containing a phosphoric acid group, and 100 to 300 parts by weight of a urea-based compound, 3 to 9 hours at 20 to 40 ° C. Reacting during, washing and primary drying;
(2) heat-treating the chitin dried in step (1) at 140-180° C. for 10-100 minutes, then washing the heat-treated chitin with a caustic soda solution to make it gel, and washing with water to swell;
(3) fibrillating chitin using a high-speed grinder, homogenizer, or super mass collidor so that the chitin swollen in step (2) has a width of 3 nm to 3 μm;
(4) secondarily drying the chitin fibrillated in step (3) at 30 to 100° C.; and
(5) preparing a powder having a diameter of 10 to 3,000 μm by pulverizing the secondarily dried chitin fibrils in step (4); The method of claim 1, wherein the chitin in step (1) is α-chitin or β-chitin. The method of claim 1, wherein the compound containing a phosphoric acid group in step (1) is any one selected from monobasic ammonium phosphate, dibasic ammonium phosphate ((NH ₄ ) ₂ HPO ₄ ) and sodium dihydrogen phosphate. Method for producing a natural biodegradable superabsorbent characterized in that. The method of claim 1, wherein the urea-based compound in step (1) is any one selected from urea, thio urea and dimethyl urea. The method of claim 1, immediately before fibrillation in step (3), CMC (carboxy methyl cellulose), citric acid, konjac, alginic acid, carrageenan, pentane, cyclopentane, hexane ( hexane), cyclohexane, heptane, cycloheptane, butanol, and isobutanol, and then fibrillating the swollen chitin. A method for producing a natural biodegradable superabsorbent. The method of claim 1, wherein the fibrils in step (3) have an average width of 3 to 100 nm. The method of claim 1, between step (3) and step (4), based on 100 parts by weight of fibrillated chitin obtained in step (3), oxidized starch, cationic starch, phosphate starch, carrageenan, Adding any one selected from konjac and alginic acid in an amount of 1 to 40 parts by weight. The method of claim 1, between the step (3) and the step (4), based on 100 parts by weight of the fibrillated chitin obtained in the step (3), epichlorohydrin, glyoxal ( A method for producing a natural biodegradable superabsorbent further comprising the step of adding 1 to 10 parts by weight of any one selected from glyoxal and maleic acid. The method of claim 1, wherein the secondary drying is drying by heat treatment; Solvent drying by adding any one organic solvent selected from methanol, ethanol, isopropanol, butanol, acetone and toluene; freeze drying; and vacuum drying; Method for producing a natural biodegradable super absorbent, characterized in that the drying of any one selected from. A sanitary product comprising a natural biodegradable super absorbent produced by the method of any one of claims 1 to 9. [Claim 11] The sanitary product of claim 10, wherein the sanitary product is any one sanitary product selected from among diapers for infants, diapers for adults, panty liners, sanitary napkins, and tampons.

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