KR102539847B1 - Method for manufacturing cellulose-based porous material and cellulose-based porous material manufactured by the same - Google Patents

Abstract

The present invention relates to a method for preparing a cellulose-based porous material having excellent biodegradability, water absorption, and elastic recovery, and to a cellulose-based porous material produced thereby.

Description

Method for producing a cellulose-based porous material and a cellulose-based porous material produced thereby

The present invention relates to a method for producing a cellulose-based porous material and a cellulose-based porous material produced thereby.

A super absorbent polymer (SAP) refers to a hydrophilic polymer having a three-dimensionally crosslinked structure, and is a functional material capable of absorbing water-soluble liquid thousands of times its own weight. However, since the main raw material of commercially used SAP is a petroleum-based polymer, various problems such as petroleum resource depletion, carbon dioxide emission, and environmental pollution due to recalcitrance appear.

Among these, cellulose, a natural biomass resource, is the most abundant natural polymer on earth, and fine fibers such as cellulose nanofibrils (CNF), which are finely chopped into nano or micro units, have a high aspect ratio and excellent mechanical strength, so porous materials are manufactured. It is an excellent material for

Porous materials such as airgel, xerogel, and cryogel prepared based on CNF are filled with air most of the volume, so the density is as low as 0.003 to 0.5 g/cm ³ and the specific surface area is high. Therefore, it can be used as a moisture absorption, sound absorption, and heat insulation material, and can be applied to various fields such as medical scaffolds.

CNF-based porous materials are mainly manufactured through processes including freeze-drying. Freeze-drying refers to a method of drying by freezing a material and sublimating the ice into vapor by lowering the partial pressure of water vapor. Freeze-drying prevents re-agglomeration of materials and minimizes damage to heat-sensitive materials.

However, this method has disadvantages in that drying is time-consuming, expensive, and expensive equipment is required. Therefore, this method is suitable for small-scale production, and there is a need for a method capable of shortening the drying time and drying at low cost for commercial use.

The technical problem to be achieved by the present invention is to provide a method for producing a cellulose-based porous material having excellent biodegradability, water absorption, and elastic recovery in a short time and at low cost, and the cellulose-based porous material produced thereby.

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

An exemplary embodiment of the present invention comprises the steps of producing pulp using a biomass raw material; preparing cellulose fibers including at least one of cellulose microfibers and cellulose fibrils from the pulp; preparing a suspension containing the cellulose fibers and a solvent; preparing a hydrogel by adding a crosslinking agent to the suspension; Freezing the hydrogel; and drying the frozen hydrogel at a temperature of 15° C. or higher for 36 hours or less.

In addition, one embodiment of the present invention provides a cellulose-based porous material prepared by the above manufacturing method.

The method for manufacturing a cellulose-based porous material according to an exemplary embodiment of the present invention can stably manufacture a porous material having a three-dimensional network structure.

In addition, the method for manufacturing a cellulose-based porous material according to an exemplary embodiment of the present invention can manufacture a cellulose-based porous material in an eco-friendly and efficient manner.

In addition, the method for producing a cellulose-based porous material according to an exemplary embodiment of the present invention enables drying of a hydrogel at low cost and within a short time, so that a large amount of porous material can be efficiently manufactured.

In addition, the cellulose-based porous material according to an exemplary embodiment of the present invention may have excellent biodegradability, water absorption rate, elasticity, and resilience.

However, the effects of the present invention are not limited to the above-described effects, and may be variously extended within a range that does not deviate from the spirit and scope of the present invention.

1 shows the degree of recovery after repeated compression of the cellulose-based airgel prepared in Example 1 of the present invention 5 times.

Throughout the present specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Throughout the present specification, when a member is said to be located “on” another member, this includes not only a case where a member is in contact with another member, but also a case where another member exists between the two members.

Hereinafter, the present invention will be described in more detail.

An exemplary embodiment of the present invention comprises the steps of producing pulp using a biomass raw material; preparing cellulose fibers including at least one of cellulose microfibers and cellulose fibrils from the pulp; preparing a suspension containing the cellulose fibers and a solvent; preparing a hydrogel by adding a crosslinking agent to the suspension; Freezing the hydrogel; and drying the frozen hydrogel at a temperature of 15° C. or higher for 36 hours or less.

The method for manufacturing a cellulose-based porous material according to an exemplary embodiment of the present invention can stably manufacture a porous material having a three-dimensional network structure. In addition, the method for manufacturing a cellulose-based porous material according to an exemplary embodiment of the present invention can manufacture a cellulose-based porous material in an eco-friendly and efficient manner. In addition, the method for producing a cellulose-based porous material according to an exemplary embodiment of the present invention enables drying of a hydrogel at low cost and within a short time, so that a large amount of porous material can be efficiently manufactured.

According to an exemplary embodiment of the present invention, the biomass raw material may include at least one of a woody biomass raw material and a non-woody biomass raw material. Specifically, the woody biomass raw material may include at least one of coniferous wood chips and hardwood wood chips, but the type of the woody biomass raw material is not limited. In addition, the non-woody biomass raw material may include at least one of kenaf, hemp, rice, bagasse, bamboo, seaweed, corn cob, corn core, rice straw, rice hull, wheat straw, and sugarcane cob. However, the type of the non-woody biomass raw material is not limited. By using the aforementioned kind of biomass raw material, it is possible to manufacture the cellulose-based porous material, which has high biodegradability and is an environmentally friendly material.

According to an exemplary embodiment of the present invention, preparing the pulp may include reacting the biomass raw material with a mixed solvent of a glycol ether-based solvent and an acid. That is, organic solvent pulp can be produced from the biomass raw material. Specifically, pulp may be formed by reacting a biomass raw material with a mixed solvent of a glycol ether solvent and an acid. When pulp is formed by reacting a biomass raw material with a mixed solvent of a glycol ether-based solvent and an acid, physical properties such as moisture absorption, moisture retention, and elastic resilience of the porous material can be effectively improved.

According to an exemplary embodiment of the present invention, the mixed solvent may be a mixture of a glycol ether-based solvent and an acid. The glycol ether-based solvent is ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and dipropylene glycol methyl ether. However, the type of the glycol ether-based solvent is not limited. In addition, hydrochloric acid, sulfuric acid, nitric acid, etc. may be used as the acid, but the type of acid is not limited.

According to an exemplary embodiment of the present invention, the volume ratio of the glycol ether-based solvent and the acid in the mixed solvent may be 95:5 to 99:1. Specifically, the volume ratio of the glycol ether-based solvent and the acid included in the mixed solvent may be 96:4 to 98.5:1.5, 96.5:3.5 to 98:2, or 97:3 to 97.5:2.5. When the volume ratio of the glycol ether-based solvent and the acid contained in the mixed solvent is within the above range, pulp can be effectively produced from the biomass raw material.

According to an exemplary embodiment of the present invention, in the step of forming the pulp, the mixed solvent may be reacted at a mixing ratio of 1 L to 3 L with respect to 1 Kg of the biomass raw material. Specifically, the mixing ratio of the mixed solvent with respect to 1 Kg of the biomass raw material may be 1.5 L to 2.5 L, or 2 L. By adjusting the mixing ratio of the biomass raw material and the mixed solvent within the above-described range, the yield of the produced pulp can be improved.

According to an exemplary embodiment of the present invention, the forming of the pulp may be performed at a temperature of 100 °C or more and 150 °C or less. Specifically, the temperature in the step of forming the pulp may be 110 °C or more and 140 °C or less, or 120 °C or more and 130 °C or less. By adjusting the temperature at which the step of forming the pulp is performed within the above range, the pulp may be stably formed from the biomass raw material.

In addition, the forming of the pulp may be performed for 60 minutes or more and 180 minutes or less, 90 minutes or more and 160 minutes or less, or 120 minutes or more and 150 minutes or less. When the time for performing the step of forming the pulp is within the above range, the pulp can be stably formed and the yield of the pulp can be improved.

According to an exemplary embodiment of the present invention, in the step of preparing the pulp, pulp may be prepared from the biomass raw material through a chemical pulping method, a mechanical pulping method, or a chemical-mechanical pulping method. In addition, in the step of preparing the pulp, kraft pulp, sulfite pulp, seaweed pulp, and the like may be manufactured using the biomass raw material. In addition, the prepared pulp may be used after being bleached or used without being bleached.

According to an exemplary embodiment of the present invention, the prepared pulp may be washed. Specifically, impurities contained in the pulp may be removed using distilled water. Through this, it is possible to effectively prevent deterioration of physical properties of the manufactured cellulose-based porous material.

According to an exemplary embodiment of the present invention, the preparing of the cellulose fibers may include preparing a pulp slurry by mixing the pulp with a basic solution; and introducing the pulp slurry into a mixer and kneading to prepare the cellulose microfibers. That is, by performing the above process, cellulose microfibers can be produced from the pulp.

According to an exemplary embodiment of the present invention, the basic solution may include a sodium hydroxide solution, a potassium hydroxide solution, and a lithium hydroxide solution, but the type of the basic solution is not limited.

According to an exemplary embodiment of the present invention, the concentration of the basic solution included in the pulp slurry may be 0.1 N or more and 1 N or less. Specifically, the concentration of the basic solution may be 0.15 N or more and 0.8 N or less, 0.2 N or more and 0.6 N or less, or 0.25 N or more and 0.5 N or less. When the concentration of the basic solution is within the above range, cellulose microfibers may be effectively formed from the pulp slurry.

According to an exemplary embodiment of the present invention, the pH of the pulp slurry may be 8 or more and 14 or less. Specifically, the pH of the pulp slurry may be 9 or more and 13 or less, or 10 or more and 12 or less. Cellulose microfibers can be effectively formed from the pulp slurry by adjusting the pH of the pulp slurry to the above range. In addition, when the pH of the pulp slurry is within the above-described range, swelling of the fibers included in the pulp slurry is promoted, and finer cellulose microfibers can be effectively manufactured through a kneading process described later.

According to an exemplary embodiment of the present invention, with respect to 100 parts by weight of the pulp slurry, the content of the pulp may be 3 parts by weight or more and 15 parts by weight or less. Specifically, with respect to 100 parts by weight of the pulp slurry, the content of the pulp is 4.5 parts by weight or more and 12.5 parts by weight or less, 5 parts by weight or more and 10 parts by weight or less, 3 parts by weight or more and 10 parts by weight or less, or 7.5 parts by weight or more 15 It may be less than parts by weight. For example, the content of the pulp included in the pulp slurry may be 3% by weight or more and 15% by weight or less.

By adjusting the content of the pulp included in the pulp slurry to the above-described range, friction and dispersion between fibers are efficiently performed during a kneading process using a mixer, so that micronized cellulose microfibers can be easily manufactured. On the other hand, if the content of the pulp included in the pulp slurry is too small, friction efficiency between fibers is lowered, making it impossible to easily manufacture micronized cellulose microfibers. In addition, when the content of the pulp included in the pulp slurry is too large, the pulp slurry has a high viscosity and is not smoothly kneaded.

According to one embodiment of the present invention, the kneading may be performed at a rotational speed of 100 rpm or more and 600 rpm or less. Specifically, the rotation speed at which the kneading step is performed may be 150 rpm or more and 550 rpm or less, 200 rpm or more and 500 rpm or less, 250 rpm or more and 450 rpm or less, or 300 rpm or more and 400 rpm or less. By adjusting the rotational speed at which the kneading step is performed within the above-mentioned range, the manufactured cellulose microfibers can be formed more stably. The rotational speed may mean the rotational speed of a mixer used in the kneading step.

According to an exemplary embodiment of the present invention, the kneading may be performed at a temperature of 20 °C or more and 35 °C or less. By controlling the temperature in the kneading step within the above range, it is possible to suppress deformation and damage of the cellulose microfibers to be manufactured.

According to an exemplary embodiment of the present invention, in the method for manufacturing cellulose microfibers, physical properties of the cellulose microfibers may be controlled by adjusting the kneading time. Specifically, the kneading may be performed for 1 hour or more and 3 hours or less. Through this, it is possible to effectively improve physical properties such as water absorption, water retention, and elastic recovery of the cellulose-based porous material produced.

According to an exemplary embodiment of the present invention, the mixer into which the pulp slurry is introduced is a kneader, and may be a Hobart mixer, a spiral mixer, or a vertical mixer. However, the type of the mixer is not limited, and a known device capable of applying shear force to the pulp slurry may be used.

According to one embodiment of the present invention, the preparing of the cellulose fibers may include preparing the cellulose fibrils by homogenizing the pulp. Specifically, cellulose fibrils may be prepared by homogenizing the aforementioned organic solvent pulp. Through this, cellulose nanofibrils (CNF) or microfibrillated cellulose (MFC) can be prepared. In order to homogenize the pulp, a high-pressure homogenizer or a high-pressure emulsifier used in the art may be used. For example, when the pulp is homogenized using a high-pressure homogenizer, the size, shape, etc. You can control it.

According to an exemplary embodiment of the present invention, the lignin content of the cellulose fibers may be 30% by weight or less. That is, the lignin content of the cellulose microfibers prepared from the pulp may be 30% by weight or less, and the lignin content of the cellulose fibrils prepared from the pulp may be 30% by weight or less. Specifically, the lignin content of the prepared cellulose fibers is 0.1% by weight or more and 30% by weight or less, 1% by weight or more and 28% by weight or less, 5% by weight or more and 25% by weight or less, 10% by weight or more and 22.5% by weight or less, or 15 It may be greater than or equal to 20% by weight and less than or equal to 20% by weight. On the other hand, by removing lignin by bleaching the prepared cellulose fiber, it is possible to form a cellulose fiber having a lignin content of 0% by weight.

When the lignin content of the cellulose fibers is within the above-mentioned range, physical properties such as water absorption, water retention, elastic recovery, and tensile strength of the cellulose-based porous material produced can be effectively improved.

According to an exemplary embodiment of the present invention, the size of the cellulose fibers may be 0.1 μm or more and 500 μm or less. That is, the size of the cellulose microfibers prepared from the pulp may be 0.1 μm or more and 500 μm or less, and the size of the cellulose fibrils prepared from the pulp may be 0.1 μm or more and 500 μm or less. Specifically, the size of the cellulose fibers is 1 μm or more and 475 μm or less, 5 μm or more and 450 μm or less, 10 μm or more and 400 μm or less, 20 μm or more and 375 μm or less, 30 μm or more and 350 μm or less, 40 μm or more and 320 μm or less. , 0.1 μm or more and 100 μm or less, 10 μm or more and 100 μm or less, 15 μm or more and 97.5 μm or less, 20 μm or more and 95 μm or less, or 25 μm or more and 92.5 μm or less. When the size of the cellulose fibers is within the above-described range, water absorption, water retention, and elastic resilience of the cellulose-based porous material produced can be effectively improved. In addition, the size of the cellulose fibers may mean the average size of the particles.

According to an exemplary embodiment of the present invention, a suspension may be prepared by mixing the cellulose fibers and a solvent. Distilled water, water, acetone, ethanol, methanol, etc. may be used as the solvent.

According to an exemplary embodiment of the present invention, based on 100 parts by weight of the suspension, the content of the cellulose fibers may be 0.5 parts by weight or more and 10 parts by weight or less. Specifically, the content of the cellulose fibers included in the suspension is 1 part by weight or more and 8.5 parts by weight or less, 1 part by weight or more and 5 parts by weight or less, 1 part by weight or more and 3 parts by weight or less, 2.5 parts by weight or more, based on 100 parts by weight of the suspension. It may be 7.5 parts by weight or more, 4.5 parts by weight or more and 6 parts by weight or less, 0.5 parts by weight or more and 5 parts by weight or less, or 5 parts by weight or more and 10 parts by weight or less. By adjusting the content of the cellulose fibers included in the suspension to the above range, the hydrogel can be effectively prepared.

According to one embodiment of the present invention, the molar ratio of the cellulose fibers and the crosslinking agent may be 1:0.1 to 1:10. Specifically, the molar ratio of the cellulose fibers and the crosslinking agent included in the suspension is 1:0.3 to 1:8.5, 1:0.5 to 1:7, 1:1 to 1:5, 1:1 to 1:3, 1 :0.1 to 1:5, 1:0.5 to 1:3.5, or 1:1 to 1:2. When the molar ratio of the cellulose fibers and the crosslinking agent included in the suspension is within the above range, crosslinking between the cellulose fibers can be effectively formed, whereby a porous material having a three-dimensional network structure can be stably formed. Through this, it is possible to effectively improve physical properties such as water absorption, water retention, and elastic recovery of the cellulose-based porous material produced.

According to an exemplary embodiment of the present invention, the crosslinking agent may include any one of an epoxy-based compound and an aldehyde-based compound.

According to an exemplary embodiment of the present invention, the crosslinking agent may include an epoxy-based compound. Specifically, the epoxy-based compound is epichlorohydrin, glycerol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, ethylene glycol diglycidyl ether , diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, resorcinol diglycidyl Cydyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, polybutadiene diglycidyl ether, trimethylolpropane polyglycidyl ether , sorbitol polyglycidyl ether or pentaerythritol polyglycidyl ether. More specifically, the epoxy-based compound may include at least two or more glycidyl groups in a molecular structure. By using an epoxy-based compound as the crosslinking agent, crosslinking between the cellulose fibers can be effectively formed. In addition, when an epoxy-based compound is used as a crosslinking agent, the prepared cellulose-based porous material does not dissociate in water even when immersed in water and can stably maintain its shape.

According to an exemplary embodiment of the present invention, the crosslinking agent may include an aldehyde-based compound. Specifically, the aldehyde-based compound is glutaraldehyde, formaldehyde, dialdehyde starch, succinic aldehyde, acrylaldehyde, oxalaldehyde, 2-methylacrylaldehyde, 2-oxopropanal, dextrin aldehyde, greeoxal, succinic aldehyde and at least one of diphaldehyde. By using an aldehyde-based compound as the crosslinking agent, crosslinking between the cellulose fibers can be effectively formed, whereby a porous material having a three-dimensional network structure can be stably formed. Through this, it is possible to effectively improve physical properties such as water absorption, water retention, and elastic recovery of the cellulose-based porous material produced.

According to an exemplary embodiment of the present invention, preparing the hydrogel may include adding a basic catalyst to the suspension. A crosslinking reaction between the cellulose fibers may be promoted by adding the basic catalyst to a suspension containing the cellulose fibers and the crosslinking agent. In addition, by using the basic catalyst, there is an advantage in that the time of the crosslinking reaction can be shortened and the temperature at which the crosslinking reaction is performed can be lowered. The basic catalyst may include at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

According to one embodiment of the present invention, the molar ratio of the cellulose fibers and the basic catalyst may be 1:0.1 to 1:3. Specifically, the molar ratio of the cellulose fibers and the basic catalyst may be 1:0.3 to 1:2.5, 1:0.5 to 1:2, 1:0.7 to 1:1.8, or 1:1 to 1:1.5. When the amount of the basic catalyst included in the suspension is within the above range, the crosslinking reaction between the cellulose fibers is effectively promoted, thereby reducing the manufacturing process time of the cellulose-based porous material and improving manufacturing efficiency.

According to an exemplary embodiment of the present invention, the step of preparing the hydrogel may be performed at a temperature of 20 ° C. or more and 100 ° C. or less for a time of 5 minutes or more and 180 minutes or less. Specifically, the step of preparing the hydrogel is 25 ° C or more and 85 ° C or less, 30 ° C or more and 70 ° C or less, 35 ° C or more and 55 ° C or less, 40 ° C or more and 100 ° C or less, 50 ° C or more and 90 ° C or less, or 60 ° C or more It may be performed at a temperature of 80 °C or less. In addition, the step of preparing the hydrogel may be performed for 15 minutes or more and 160 minutes or less, 30 minutes or more and 140 minutes or less, 45 minutes or more and 120 minutes or less, or 60 minutes or more and 90 minutes or less. By adjusting the temperature and time for preparing the hydrogel within the above range, the hydrogel can be stably prepared from the suspension.

According to an exemplary embodiment of the present invention, the step of freezing the hydrogel may be ice-templating the hydrogel using a freezer or liquid nitrogen. Porous materials may be prepared by freezing the hydrogel to form pores therein, and then removing the solvent through drying the frozen hydrogel.

According to an exemplary embodiment of the present invention, the step of freezing the hydrogel may be performed at a temperature of -50 ° C or more and -5 ° C or less for a time of 1 hour or more and 12 hours or less. Specifically, the step of freezing the hydrogel may be performed at a temperature of -50 °C or more -5 °C or less, -40 °C or more -10 °C or less, or -30 °C or more -20 °C or less. In addition, the step of freezing the hydrogel is 1 hour or more and 12 hours or less, 1 hour or more and 10 hours or less, 1 hour or more and 8 hours or less, 1 hour or more and 6 hours or less, 1 hour or more and 4 hours or less, 1 hour or more and 3 hours or more. Hereinafter, it may be performed for a time of 3 hours or more and 10 hours or less, 3 hours or more and 8 hours or less, or 3 hours or more and 6 hours or less. By adjusting the range of temperature and time for freezing the hydrogel to the above range, the solvent contained in the hydrogel can be effectively frozen, and through this, pores can be efficiently formed in the hydrogel. In addition, the time and cost of manufacturing the cellulose-based porous material can be further reduced.

According to an exemplary embodiment of the present invention, the step of drying the frozen hydrogel may be performed at a temperature of 15 ° C or higher for a time of 36 hours or less. By adjusting the temperature and time for drying the frozen hydrogel within the above-mentioned range, the solvent contained in the hydrogel can be effectively removed, thereby improving drying efficiency, and does not require expensive equipment, so that it can be continuously operated at low cost. Mass drying can be performed. Through this, mass production of the cellulose-based porous material is possible, manufacturing cost can be effectively reduced, and it can be easily applied to various fields.

According to an exemplary embodiment of the present invention, drying the frozen hydrogel may be performed by hot air drying, reduced pressure drying, or natural drying. By drying by the method of hot air drying, reduced pressure drying, or natural drying, the finally produced cellulose-based porous material does not re-aggregate after drying, so it may have excellent dimensional stability, excellent moisture absorption and elastic recovery. In addition, the drying time can be shortened compared to the freeze-drying method, and since expensive freeze-drying equipment is not required, efficient mass production at low cost may be possible.

According to an exemplary embodiment of the present invention, the drying of the hydrogel may be performed at a temperature of 50 ° C. or more and 200 ° C. or less for 1 hour or more and 12 hours or less under conditions of normal pressure (1 ± 0.2 atm). . That is, the hydrogel may be dried through hot air drying.

Specifically, the hot air drying may be performed at a temperature of 50 °C or more and 200 °C or less, 60 °C or more and 200 °C or less, 100 °C or more and 200 °C or less, or 105 °C or more and 200 °C or less. In addition, the hot air drying may be performed for 1 hour or more and 12 hours or less, 1 hour or more and 10 hours or less, 1 hour or more and 6 hours or less, 1 hour or more and 3 hours or less, or 3 hours or more and 6 hours or less. When the temperature and time ranges of the hot air drying are within the above-described ranges, heat-induced damage to the hydrogel can be prevented, and a porous structure of a cellulose-based porous material can be more easily formed. In addition, by adjusting the temperature and time at which the hot air drying is performed within the above range, the solvent frozen in the hydrogel can be quickly and effectively removed, thereby stably forming the porous structure of the cellulose-based porous material. there is. In addition, compared to the freeze-drying method, which requires a long drying time, the hydrogel can be dried quickly and at a low cost, so that a large amount of porous material can be efficiently produced.

According to an exemplary embodiment of the present invention, the drying of the hydrogel may be performed at a pressure of 1 mTorr or more and 50 mTorr or less and a temperature of 15 ° C. or more and 100 ° C. or less for 3 hours or more and 24 hours or less. That is, the hydrogel may be dried by drying under reduced pressure at room temperature or drying under reduced pressure at high temperature.

According to an exemplary embodiment of the present invention, the pressure at which the reduced pressure drying is performed is 1 mTorr or more and 50 mTorr or less, 5 mTorr or more and 45 mTorr or less, 10 mTorr or more and 40 mTorr or less, 15 mTorr or more and 35 mTorr or less, or 20 mTorr or more 30 mTorr or less. may be less than mTorr. By adjusting the pressure at which the reduced pressure drying is performed within the above range, the solvent frozen in the hydrogel can be sublimated even at a low temperature, so that the solvent frozen in the hydrogel can be quickly and effectively removed. In addition, pores are formed where ice crystals in the frozen hydrogel are sublimated into gaseous vapor, so that a porous structure of a cellulose-based porous material can be effectively obtained.

According to an exemplary embodiment of the present invention, when the hydrogel is dried under reduced pressure at room temperature, the temperature at which the reduced-pressure drying is performed may be 15° C. or more and 30° C. or less. In addition, the normal temperature and reduced pressure drying is 3 hours or more and 24 hours or less, 3 hours or more and 12 hours or less, 4 hours or more and 12 hours or less, 5 hours or more and 12 hours or less, 6 hours or more and 12 hours or less, 6 hours or more and 18 hours or less, 8 More than 16 hours, more than 10 hours and less than 14 hours, more than 12 hours and less than 24 hours, more than 12 hours and less than 22 hours, more than 12 hours and less than 20 hours, or more than 12 hours and less than 18 hours. The solvent frozen in the hydrogel can be effectively removed by adjusting the temperature and pressure at which the reduced pressure drying is performed within the above range. Through this, a porous structure of a cellulose-based porous material can be formed at a low cost compared to a freeze-drying method requiring expensive equipment, and damage to heat-sensitive materials can be minimized.

According to an exemplary embodiment of the present invention, when the hydrogel is dried under high temperature and reduced pressure, the temperature at which the reduced pressure drying is performed may be greater than 30 °C and less than 100 °C. Specifically, it may be 45 ° C or higher, 40 ° C or higher, 45 ° C or higher, 50 ° C or higher, 55 ° C or higher or 60 ° C or higher, and may be 100 ° C or lower, 95 ° C or lower, 90 ° C or lower, 85 ° C or lower or 80 ° C or lower. . In addition, the high-temperature reduced pressure drying is 3 hours or more and 24 hours or less, 3 hours or more and 12 hours or less, 4 hours or more and 12 hours or less, 5 hours or more and 12 hours or less, 6 hours or more and 12 hours or less, 6 hours or more and 18 hours or less, 8 more than 16 hours, more than 10 hours and less than 14 hours, more than 12 hours and less than 24 hours, more than 12 hours and less than 22 hours, more than 12 hours and less than 20 hours, or more than 12 hours and less than 18 hours. When the temperature, pressure, and time of the reduced pressure drying are within the range, heat-induced damage to the hydrogel can be prevented, and the formation of a porous structure of a cellulose-based porous material can be facilitated. By adjusting the temperature, pressure and time at which the reduced pressure drying is performed within the above range, the solvent frozen in the hydrogel can be quickly and effectively removed, and through this, a porous structure of a cellulose-based porous material can be stably formed. there is. In addition, compared to the freeze-drying method, which requires a long drying time, the hydrogel can be dried quickly and at a low cost, so that a large amount of porous material can be efficiently produced.

According to an exemplary embodiment of the present invention, the drying of the hydrogel may be performed for 24 hours or more and 36 hours or less under conditions of room temperature and pressure (23±5° C., 1±0.2 atm). That is, the hydrogel may be dried through natural drying. When the temperature, pressure, and time range of the natural drying are within the range, the drying efficiency may be increased, mass production may be possible, and the formation of a porous structure of a cellulose-based porous material may be facilitated. By naturally drying the frozen hydrogel for a time within the above-mentioned range, it is possible to stably form a porous structure of a cellulose-based porous material. In addition, compared to the freeze-drying method, which requires a long drying time, the drying efficiency is improved by having a shorter drying time, and damage to heat-sensitive materials can be minimized. In addition, since it does not require expensive equipment, it is possible to dry the hydrogel in a short time at low cost, so that a large amount of porous material can be efficiently manufactured. On the other hand, depending on the solid content contained in the pulp slurry prepared in the step of preparing the cellulose fibers, the drying time at room temperature and normal pressure conditions can be adjusted. For example, the drying at room temperature and pressure conditions may be performed for 48 hours or less, or less than 48 hours. When within the range of temperature, pressure and time of the natural drying, it is possible to stably form the porous structure of the cellulose-based porous material, and it is possible to dry the hydrogel at low cost without the need for expensive equipment, freeze drying method In contrast, a large amount of porous material can be efficiently produced.

An exemplary embodiment of the present invention provides a cellulose-based porous material prepared by the above manufacturing method.

The cellulose-based porous material according to an exemplary embodiment of the present invention may have excellent biodegradability, water absorption rate, elasticity, and resilience.

According to an exemplary embodiment of the present invention, the cellulose-based porous material may be formed in the form of airgel, xerogel, or cryogel.

According to an exemplary embodiment of the present invention, the density of the cellulose-based porous material before drying may be 1.0 g/cm ³ or more, and the density after drying may be 0.05 g/cm ³ or more. Specifically, the density of the cellulose-based porous material before drying may be 1.00 g/cm ³ or more, 1.01 g/cm ^{3 or} more, 1.02 g/cm ³ or more, or 1.03 g/cm ³ or more. In addition, the density of the cellulose-based porous material after drying may be 0.05 g/cm ³ or more, 0.06 g/cm ³ or more, or 0.07 g/cm ³ or more. The cellulose-based porous material satisfying the above-described density range has excellent mechanical strength, high water absorption and elastic recovery, and may be suitable for manufacturing the cellulose-based porous material under a temperature condition of 15 ° C. or higher.

According to an exemplary embodiment of the present invention, the density of the cellulose-based porous material before drying may be 1.5 g/cm ³ or less, and the density after drying may be 1.0 g/cm ³ or less. Specifically, the density of the cellulose-based porous material before drying is 1.4 g/cm ³ or less, 1.3 g/cm ³ or less, 1.2 g/cm ^{3 or} less, 1.1 g/cm ³ or less, 1.09 g/cm ³ or less, or 1.08 g /cm ³ or less. In addition, the density of the cellulose-based porous material after drying may be 1.0 g/cm ³ or less, 0.95 g/cm ³ or less, or 0.90 g/cm ³ or less. The cellulose-based porous material that satisfies the above-mentioned range of density does not re-aggregate after drying, so it has excellent dimensional stability, high water absorption and elastic recovery. In addition, it is possible to form a three-dimensional network pore structure with a high specific surface area compared to low density, and since most of the volume is filled with air, it has excellent moisture absorption, sound absorption and insulation effects, so it can be used as a moisture absorption, sound absorption and insulation material. .

According to an exemplary embodiment of the present invention, the volume change rate of the cellulose-based porous material before drying and after drying may be 20% or more and 35% or less. Specifically, the volume change rate of the porous material before and after drying is 22% or more and 35% or less, 23% or more and 35% or less, 24% or more and 35% or less, 25% or more and 35% or less, 25% or more and 34% or less, 25 % or more and 33% or less, 26% or more and 32% or less, or 26% or more and 31% or less. The cellulose-based porous material that satisfies the volume change rate in the above range has a stable three-dimensional network pore structure even when dried at high temperature, can have excellent dimensional stability after drying, and has physical properties such as water absorption, water retention and elastic recovery this can be great

According to one embodiment of the present invention, the water absorption rate of the cellulose-based porous material may be 1,000% or more. Specifically, the water absorption rate of the cellulose-based porous material is 1,000% or more and 6,000% or less, 1,100% or more and 6,000% or less, 1,100% or more and 6,000% or less, 1,200% or more and 6,000% or less, 1,300% or more and 6,000% or less, 1,400% or more 6,000% or less, 1,500% or more and 6,000% or less, 2,000% or more and 6,000% or less, or 2,500% or more and 6,000% or less. The moisture absorption rate of the cellulose-based porous material may be further increased according to the density control during manufacture of the cellulose-based porous material, and the cellulose-based porous material satisfying the moisture absorption rate in the above range may be effectively applied to a moisture absorbing material.

According to an exemplary embodiment of the present invention, the moisture retention per 1 g of the cellulose-based porous material may be 10 g or more. Specifically, the water retention per 1 g of the cellulose-based porous material is 10 g or more and 60 g or less, 11 g or more and 60 g or less, 12 g or more and 60 g or less, 13 g or more and 60 g or less, 14 g or more and 60 g or less, or 15 g It may be more than 60 g or less. The cellulose-based porous material that satisfies the water retention in the above range can be effectively applied to a moisture absorbing material.

According to one embodiment of the present invention, the elastic recovery force of the cellulose-based porous material may be 80% or more. The elastic recovery force of the cellulose-based porous material can be obtained through a method described later. Specifically, the elastic recovery after one-time compression of the cellulose-based porous material may be 80% or more, 83% or more, 85% or more, 87% or more, 90% or more, 93% or more, 95% or more, or 97% or more, The elastic recovery after 5 times of compression of the cellulose-based porous material is 80% or more, 82% or more, 84% or more, 86% or more, 80% or more, 83% or more, 85% or more, 86% or more, 88% or more, 90 % or more, 91% or more, or 92% or more. The cellulose-based porous material that satisfies the elastic restoring force within the above range has excellent elastic restoring force and dimensional stability according to repeated compression, and thus can be applied to various fields such as medical scaffolds.

According to an exemplary embodiment of the present invention, the tensile strength of the cellulose-based porous material may be 0.03 N/mm ² or more. Specifically, the tensile strength of the cellulose-based porous material is 0.03 N/mm ² or more, 0.04 N/mm ² or more, 0.05 N/mm ^{2 or} more, 0.06 N/mm ^{2 or} more, 0.07 N/mm ^{2 or} more, 0.08 N/ mm ² or more, 0.09 N/mm ² or more, or 0.10 N/mm ² or more. In addition, the tensile strength of the cellulose-based porous material may be 0.20 N/mm ² or less, 0.18 N/mm ² or less, 0.16 N/mm ^{2 or} less, 0.14 N/mm ^{2 or} less, or 0.12 N/mm ^{2 or} less.

According to an exemplary embodiment of the present invention, the compressive strength of the cellulose-based porous material may be 0.05 N/mm ² or more. Specifically, the compressive strength of the cellulose-based porous material is 0.05 N/mm ² or more, 0.06 N/mm ² or more, 0.07 N/mm ² or more, 0.08 N/mm ^{2 or} more, 0.09 N/mm ^{2 or} more, 0.10 N/ mm ² or more, 0.11 N/mm ² or more, or 0.12 N/mm ² or more. In addition, the compressive strength of the cellulose-based porous material may be 0.20 N/mm ² or less, 0.18 N/mm ^{2 or} less, 0.16 N/mm ² or less, or 0.14 N/mm ² or less.

The cellulose-based porous material having tensile strength and compressive strength within the aforementioned range may have excellent mechanical properties such as durability and impact resistance against external impact.

Hereinafter, examples will be described in detail to explain the present invention in detail. However, embodiments according to the present invention can be modified in many different forms, and the scope of the present invention is not construed as being limited to the embodiments described below. The embodiments herein are provided to more completely explain the present invention to those skilled in the art.

Manufacture of Cellulose Microfibers

Preparation Example 1

Coniferous wood chips were prepared. The prepared softwood wood chips had a classone lignin content of about 28.7%, and the size of the chips was 35 (±3) mm in height X 8 (±3) mm in width X 7 (±2) mm in thickness.

Thereafter, ethylene glycol monomethyl ether as a glycol ether-based solvent and sulfuric acid (95%) as an acid were prepared, and ethylene glycol monomethyl ether and sulfuric acid were mixed in a volume ratio of 97:3 to prepare a mixed solvent.

Then, at a mixing ratio of 2 L of mixed solvent to 1 Kg of wood chips, it was put into a high-pressure steam treatment device (autoclave, HST 506-6, Hanbaek ST, Korea), reacted at 120 ° C for 120 minutes, filtered with distilled water, and 680 mL An organic solvent pulp (27.4% lignin content) having free water (CSF) was prepared.

A pulp slurry was prepared by mixing the prepared organic solvent pulp with 0.25 N NaOH aqueous solution (500 mL). At this time, the content of the organic solvent pulp was 5 parts by weight (5.0% by weight) with respect to 100 parts by weight of the pulp slurry, and the pH of the pulp slurry was about 13.

Thereafter, about 499.5 mL of the pulp slurry was added to a Hobart mixer having a maximum capacity (total volume) of 4,500 mL, and kneading was performed at a rotational speed of 281 rpm for 3 hours to obtain cellulose microfibers.

Thereafter, 2,000 mL of 0.5 N NaOH aqueous solution was added to the obtained cellulose microfibers, followed by filtration and dehydration to elute lignin. Cellulose microfibers were finally prepared by repeating the water washing process to remove residual NaOH components.

Preparation of cellulosic porous materials

Example 1

A suspension was prepared by mixing the cellulose microfibers prepared in Preparation Example 1 with distilled water. At this time, based on 100 parts by weight of the suspension, the content of the cellulose microfibers was 3 parts by weight.

Thereafter, glycerol diglycidyl ether as a crosslinking agent and sodium hydroxide as a basic catalyst were added to the suspension. At this time, the molar ratio of the cellulose microfiber:crosslinking agent:basic catalyst was 1:1:1.

Thereafter, the suspension was stirred for about 5 minutes using a stirrer, and reacted in a constant temperature water bath at 100 °C for 5 minutes to prepare a hydrogel. After freezing the prepared hydrogel in a freezer at -28 ° C. for 3 hours, it was dried in a hot air dryer (JSOP-100, JS Research Inc., Korea, temperature: 105 ° C.) for 3 hours to prepare a cellulose-based airgel. .

Example 2

In Example 1, the prepared hydrogel was frozen in a freezer at -28 ° C for 3 hours, and then dried for 12 hours in a vacuum dryer (HG-V60, HANGIL, Korea temperature: 60 ° C, pressure: 5 mTorr) Except for the above, a cellulose-based airgel was prepared in the same manner as in Example 1.

Example 3

In Example 1, except that the prepared hydrogel was frozen for 3 hours in a freezer at -28 ° C and then dried for 18 hours in an atmospheric dryer (JSOP-100, JS Research Inc., Korea temperature: 60 ° C). And, a cellulose-based airgel was prepared in the same manner as in Example 1.

Example 4

In Example 1, a cellulose-based airgel was prepared in the same manner as in Example 1, except that the prepared hydrogel was frozen in a freezer at -28 ° C. for 3 hours and then naturally dried at room temperature for 36 hours. .

Comparative Example 1

In Example 1, the prepared hydrogel was frozen in a freezer at -28 ° C for 3 hours, and then dried for 48 hours in a lyophilizer (FD8508, ILSHIN, Korea, temperature: -40 ° C, pressure: 50 mTorr) Except for the above, a cellulose-based airgel was prepared in the same manner as in Example 1.

Experimental example

Determination of residual lignin content

The residual lignin content of the cellulose microfiber prepared in Example 1 was measured as follows.

Specifically, a sample was prepared by freeze-drying the cellulose microfiber prepared in Example 1, and 5 mL of 72% sulfuric acid was added to 0.2 g of the dried cellulose microfiber sample, and the mixture was stirred every hour for 4 hours. It was allowed to stand at room temperature. Thereafter, after dilution by adding 196 mL of distilled water, the mixture was reacted for 2 hours at a temperature of 120 °C in an autoclave. After the reaction was completed, distilled water was used to vacuum and filter through a glass filter, and the residue of the glass filter was dried in a dryer at 105 °C. Then, the residual lignin content was calculated by the following formula 1.

[Equation 1]

L = W/S X 100

In Equation 1, “L” is the residual lignin content, “S” is the dry weight of the sample (g), and “W” is the weight of the dried residue (g).

density measurement

The mass and volume of the cellulose-based airgel prepared in Example 1 were measured, and the density before and after drying was calculated as the mass per unit volume.

Thereafter, the densities of the cellulose-based airgel prepared in Examples 2 to 4 and Comparative Example 1 were calculated before drying and after drying, and are shown in Table 1 below.

Volume change rate measurement

The volume change rate of the cellulose microfibers prepared in Example 1 was measured as follows.

First, the height and thickness of the specimen before drying the cellulose-based airgel were measured. Then, it was frozen for 3 hours in a freezer at -28 ° C, dried for 3 hours in a hot air dryer (temperature: 105 ° C), and the height and thickness of the cellulose-based airgel specimen were measured after drying. Then, the volume change rate of the cellulose-based airgel was calculated through the following formula 2.

[Equation 2]

V = (V ₂ - V ₁ / V ₁ ) X 100

In Equation 2, “V” is the volume change rate, “V ₁ ” is the volume of the sample before drying (cm ³ ), and “V ₂ ” is the volume of the sample after drying (cm ³ ).

Then, the volume change rate of the cellulose-based airgel prepared in Examples 2 to 4 and Comparative Example 1 was calculated and shown in Table 1 below.

Water absorption rate and water retention measurement

Water absorption and water retention of the cellulose-based airgel prepared in Example 1 were measured as follows.

The cellulose-based airgel was completely dried, and the dried cellulose-based airgel was immersed in distilled water for 24 hours. Thereafter, the cellulose-based airgel was taken out and dripping water was removed for 5 minutes, and then the water absorption rate was calculated through Equation 3 below, and the water retention amount was calculated through Equation 4 below.

[Equation 3]

W _t1 = (W - W ₀ )/W ₀ X 100

[Equation 4]

W _t2 = (W - W ₀ )/W ₀

In Equation 3, W _t1 is the water absorption rate, W is the mass of the cellulose-based airgel after immersion for 24 hours, and W ₀ is the mass of the initially dried cellulose-based airgel. In Equation 4, W _t2 is the amount of water retention, W is the mass of the cellulose-based airgel after being immersed for 24 hours, and W ₀ is the mass of the initially dried cellulose-based airgel.

Then, the water absorption and water retention of the cellulose-based airgel prepared in Examples 2 to 4 and Comparative Example 1 are shown in Table 2 below.

Elastic resilience measurement

The elastic recovery force of the cellulose-based airgel prepared in Example 1 was measured as follows.

First, the thickness of the cellulose-based airgel before compression was measured. Thereafter, the cellulose-based airgel was compressed at a strain rate of 95% under compression conditions of 50 kgf and 1 mm/min using a universal tensile strength tester, and after immersing the compressed cellulose-based airgel in distilled water for 24 hours, the cellulose-based airgel After removing the water that fell for 5 minutes, the thickness of the cellulose-based airgel was measured. After completing the experiment on the thickness of the cellulose-based airgel before compression, the elastic recovery force was obtained through the thickness ratio of the cellulose-based airgel.

[Equation 5]

E = T _n /T ₀ X 100

In Equation 5, E is the elastic recovery force, T _n is the thickness of the cellulose-based airgel after completing the nth experiment, and T ₀ is the thickness of the cellulose-based airgel before the first experiment (before compression).

Thereafter, additional compression was repeatedly performed on the airgel sample 4 times under the same conditions, and the elastic recovery force for each round was calculated by measuring the thickness of the cellulose-based airgel after the completion of each round of the experiment.

Then, the elastic recovery force measured by repeating compression 5 times under the same conditions for each sample of the cellulose-based airgel prepared in Examples 2 to 4 and Comparative Example 1 is shown in Table 3 below.

The degree of recovery by repeating compression five times under the same conditions for the cellulose-based airgel sample prepared in Example 1 is shown in FIG. 1 .

1 shows the degree of recovery after repeated compression of the cellulose-based airgel prepared in Example 1 of the present invention 5 times.

Referring to FIG. 1, it was confirmed that the cellulose-based airgel prepared in Example 1 had excellent dimensional stability and excellent elastic recovery after drying, while having a shorter drying time compared to lyophilization.

Tensile strength measurement

The tensile strength of the cellulose-based airgel prepared in Example 1 was measured as follows.

Specifically, the tensile strength of the cellulose-based airgel was measured using a universal tensile strength tester (Hounsfield H500M, England). At this time, in order to measure the tensile strength, the cellulose-based airgel was manufactured as a specimen having a height of 20 mm and a diameter of 10 mm, and the load cell load was set to 50 kgf and the tensile speed to 2 mm/min.

In addition, the tensile strength of the cellulose-based airgel prepared in Examples 2 to 4 and Comparative Example 1 was measured, and shown in Table 4 below.

Compressive strength measurement

The compressive strength of the cellulose-based airgel prepared in Example 1 was measured as follows.

Specifically, the compressive strength of the cellulose-based airgel was measured using a universal tensile strength tester (Hounsfield H500M, England). At this time, in order to measure the compressive strength, the cellulose-based airgel was prepared as a specimen having a height of 10 mm and a diameter of 10 mm, and the final strain was set to 75% and measured at a rate of 1 mm/min.

The compressive strengths of the cellulose-based airgels prepared in Examples 2 to 4 and Comparative Example 1 are shown in Table 4 below.

Density before drying (g/cm ³ ) Density after drying (g/cm ³ ) Volume change rate (%) Example 1 1.040 0.080 29.3 Example 2 1.031 0.086 30.3 Example 3 1.033 0.076 27.7 Example 4 1.034 0.074 26.8 Comparative Example 1 1.033 0.070 22.6

Water absorption rate (%) Moisture retention (g) Example 1 1425.9 14.3 Example 2 1328.4 13.3 Example 3 1388.3 13.9 Example 4 1455.8 14.6 Comparative Example 1 1487.7 14.9

Elastic recovery (%) 1 compression 2 compresses 3 compressions 4 compressions 5 compresses Example 1 94.0 93.0 91.4 91.7 92.2 Example 2 97.8 95.9 95.2 94.7 91.8 Example 3 97.0 93.5 93.3 93.1 91.7 Example 4 95.7 95.1 93.1 92.3 90.9 Comparative Example 1 98.0 96.4 94.8 93.7 92.2

Tensile strength (N/mm ² ) Compressive strength (N/mm ² ) Example 1 0.104 0.128 Example 2 0.097 0.127 Example 3 0.06 0.115 Example 4 0.105 0.116 Comparative Example 1 0.02 0.18

Referring to Tables 1 to 4, it was confirmed that the cellulose-based airgel prepared in Examples 1 to 4 of the present invention had excellent water absorption, water retention, dimensional stability, elastic recovery, tensile strength and compressive strength.

On the other hand, the cellulose-based airgel prepared in Examples 1 to 4 showed similar values in water absorption, water retention, dimensional stability, elastic recovery, tensile strength and compressive strength to the cellulose-based airgel prepared in Comparative Example 1. did

That is, in the method for producing a cellulose-based porous material according to an exemplary embodiment of the present invention, the prepared cellulose-based porous material has high biodegradability and a water absorption rate, while having a reduced drying time and relaxed drying conditions compared to freeze drying. It can be seen that the physical properties such as water retention, dimensional stability, elastic recovery, tensile strength and compressive strength are excellent.

Therefore, the method for producing a cellulose-based porous material according to an exemplary embodiment of the present invention enables drying of a hydrogel at low cost and within a short period of time, so that a large amount of porous material can be efficiently manufactured.

The foregoing detailed description is intended to illustrate and explain the present invention. In addition, the foregoing merely represents and describes preferred embodiments of the present invention, and as described above, the present invention can be used in various other combinations, modifications, and environments, and the scope of the inventive concept disclosed herein, the foregoing Changes or modifications are possible within the scope equivalent to the disclosure and / or within the scope of skill or knowledge in the art. Accordingly, the above detailed description of the invention is not intended to limit the invention to the disclosed embodiments. Also, the appended claims should be construed to cover other embodiments as well.

Claims (16)

Preparing pulp using a biomass raw material;
preparing cellulose fibers including at least one of cellulose microfibers and cellulose fibrils from the pulp;
preparing a suspension containing the cellulose fibers and a solvent;
preparing a hydrogel by adding a crosslinking agent and a basic catalyst to the suspension;
Freezing the hydrogel; and
Method for producing a cellulose-based porous material comprising: drying the frozen hydrogel at room temperature and pressure for 24 hours or more and 36 hours or less.
delete delete delete delete According to claim 1,
The step of producing the cellulose fibers,
mixing the pulp with a basic solution to prepare a pulp slurry; and
The manufacturing method of a cellulose-based porous material comprising the; preparing the cellulose microfibers by introducing the pulp slurry into a mixer and kneading.
According to claim 1,
Method for producing a cellulose-based porous material in which the lignin content of the cellulose fibers is 30% by weight or less.
According to claim 1,
Based on 100 parts by weight of the suspension, the content of the cellulose fiber is 0.5 parts by weight or more and 10 parts by weight or less.
According to claim 1,
The crosslinking agent is a method for producing a cellulose-based porous material comprising any one of an epoxy-based compound and an aldehyde-based compound.
According to claim 1,
A method for producing a cellulose-based porous material in which the molar ratio of the cellulose fibers and the crosslinking agent is 1:0.1 to 1:10.
According to claim 1,
A method for producing a cellulose-based porous material in which the molar ratio between the cellulose fibers and the basic catalyst is 1:0.1 to 1:3.
According to claim 1,
The step of preparing the hydrogel,
Method for producing a cellulose-based porous material that is performed at a temperature of 20 ° C. or more and 100 ° C. or less for a time of 5 minutes or more and 180 minutes or less.
A cellulose-based porous material produced by the method according to claim 1.
According to claim 13,
The cellulose-based porous material of which the elastic recovery of the cellulose-based porous material is 80% or more.
According to claim 13,
A cellulose-based porous material having a water absorption rate of 1,000% or more.
According to claim 13,
A cellulose-based porous material having a water retention rate of 10 g or more per 1 g of the cellulose-based porous material.

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