KR102073523B1 - A method of pulverizing a cellulose raw material exhibiting low energy characteristics, a method of producing cellulose microfibers containing the same, and a device of producing cellulose microfibers - Google Patents

Abstract

The present invention discloses a method for dissociating and extracting a cellulose raw material, comprising a first step in which a cellulose raw material and a swelling agent are mixed to swell the cellulose raw material and a second step of adding a sublimating material to the swollen cellulose raw material; a method for producing cellulose microfibers, including the method for dissociating and extracting a cellulose raw material; cellulose microfibers produced according to the production method of cellulose microfibers; and an apparatus for producing cellulose microfibers in which the production method of the cellulose microfibers can be performed. The method for producing cellulose microfibers of the present invention has advantages in terms of production cost, performance conditions, etc.

Description

A method of pulverizing a cellulose raw material exhibiting low energy characteristics, a method of producing cellulose microfibers containing a method for dissociating and extracting cellulose raw materials exhibiting low energy characteristics, a method for producing cellulose microfibers including the same, and an apparatus for producing cellulose microfibers the same, and a device of producing cellulose microfibers}

The present invention relates to a method for dissociating and extracting cellulose raw materials exhibiting low energy characteristics, a method for producing cellulose microfibers including the same, and an apparatus for producing cellulose microfibers, and more specifically, to improve energy consumption by using a sublimable material. The present invention relates to a method for pulverizing cellulose raw materials, a method for producing cellulose microfibers including the same, and an apparatus for producing cellulose microfibers, and cellulose microfibers produced according to the above method.

Nanotechnology (NT) is a technique of obtaining desired characteristics by using the unique characteristics of nano-sized particles. In order to solve environmental problems of polymer compounds based on conventional fossil fuels, interest in environmentally friendly polymers is increasing along with research of nanotechnology. As a representative example of environmentally friendly polymers, interest in cellulose is steadily increasing.

Cellulose is one of the most common polymers in nature. Thus, cellulose has advantages in terms of supply, and reproduction is also possible. In addition, cellulose has the advantage of being easily biodegradable compared to the polymer compound synthesized from crude oil.

Cellulose consists of successive bonds of two glucoses, or cellobioses, connected by β- (1-4) bonds. The number of bonds is expressed in degrees of polymerization (DP). About 10,000 and about 15,000 for cotton. The degree of polymerization is related to the length of the cellulose chains and these cellulose chains form a structure in the cell wall, called microfibril. Microfibrils are the smallest units of cellulose nanomaterials that can be physically or chemically isolated and are about 4-5 nm wide. Nanocellulose is a generic term for nm or diameter in diameter and is commonly called CNF (Cellulose Nanofibers) or MFC (Microfibrillated Cellulose). The microfibrils are arranged and clustered helically in the axial direction to form a microfibril bundle, in which the microfibrils, or part of the chain, are amorphous regions.

On the other hand, the method of isolating a cellulose raw material is largely divided into a chemical process, a biological process, and a physical process. The chemical process is a concept that collectively refers to a process of chemically dissociating a glycoside bond constituting a cellulose polymer by adding an acid catalyst or the like. When the cellulose is hydrolyzed by an acid, the above-mentioned amorphous region is hydrolyzed faster than the crystalline region. Therefore, when cellulose is hydrolyzed under appropriate conditions, it is possible to obtain a whisker-shaped cellulose nanocrystal mainly composed of the crystalline region. have. These cellulose nanocrystals have no defects, have an elastic modulus of about 150 GPa, and have excellent acid resistance, and thus may be used as composite materials and composite materials for medical engineering.

In the chemical process, however, a strong acid catalyst such as sulfuric acid is usually used for the purpose of improving the water dispersibility of a cellulose raw material or the like. Process risks, difficulties in separation and washing after hydrolysis, and environmental problems from wastewater treatment can be the limitations of mass production. In addition, sulfuric acid groups may be substituted on the surface of the cellulose nanocrystals during the hydrolysis process, and the sulfuric acid groups may cause deterioration of physical properties of cellulose fibers.

Biological processes, on the other hand, use bacteria that can break down the glycoside bonds of cellulose. The biological process has the advantage that it is particularly easy to produce cellulose microfibers in a bottom-up manner by uniform decomposition of cellulose by bacteria. However, the cost of culturing and maintaining bacteria is considerable, and the yield is not high, there is a limit that industrial production is limited.

Unlike chemical and biological processes, physical processing is a concept that collectively refers to a process of inducing isolation of cellulose by projecting external force on cellulose. Examples of physical processes include high intensity sonication, high pressure refiner treatment, grinder treatment, high pressure homogenizer treatment and the like. The physical process is simple compared to other processes, and has the characteristics that the formation of the α-anomer is limited and that the cellulose microfibers contain crystalline and amorphous relatively uniformly and thus have improved physical properties.

However, the conventional physical process had a critical limitation that about 70,000KWh of energy was consumed when producing 1 ton of cellulose microfibers. For example, when the high pressure homogenizer is used, the energy consumption may be realized under a pressure condition of 3,000 bar, and heat generated instantaneously in the process of homogenization may be 250 ° C. (for example, 270 ° C. in Korean Patent No. 10-1992492). Temperature conditions). In particular, when the homogenization is performed at a high temperature of 250 ℃ or more, unnecessary carbonization of the cellulose raw material may occur.

Thus, in order to improve the limitations of the physical process, a method of performing a physical process after chemical pretreatment, a method of performing a physical process after biological pretreatment, and the like have been proposed. However, in the above-described manner, the limitations specific to the chemical process or the biological process and the limitations of the physical process may be simultaneously expressed.

Korea Patent Registration No. 10-1992492

 I. Siro, Cellulose, pp. 459-494, 2010.

The present invention was developed to overcome the limitations of the prior art as described above, and an object of the present invention is to provide a method for dissociation and extraction of cellulose raw materials with low energy characteristics.

It is also an object of the present invention to provide a method for producing cellulose microfibers which can be carried out at low temperature.

Another object of the present invention is to provide an apparatus for producing cellulose microfibers, in which the method for dissociating and extracting the cellulose raw material and the method for producing cellulose microfibers are performed.

MEANS TO SOLVE THE PROBLEM The present inventors came to devise the invention containing the following structures as a result of researching in order to solve the above-mentioned subject. Specifically, in the present specification, a cellulose raw material and a swelling agent are mixed to swell the cellulose raw material; And a second step of adding a sublimable substance to the swollen cellulose raw material.

In the pulverization method of each cellulosic raw material of the present invention, the swelling agent is distilled water, and the sublimable material includes at least one material selected from the group consisting of dry ice, liquid nitrogen, liquid helium, liquid neon, and liquid argon. desirable.

In the method for crushing the cellulose raw materials of the present invention, the sublimable substance is more preferably dry ice.

In addition, in the grinding method of each cellulose raw material of the present invention, it is more preferable that the first step and the second step are performed at a temperature condition of 1 ° C or more and 100 ° C or less.

In addition, in the pulverization method of each cellulose raw material of the present invention, it is more preferable that the first step and the second step are performed at a temperature condition of 1 ° C or more and 10 ° C or less.

On the other hand, the present specification is a step of preparing a cellulose raw material, which is ground in accordance with any one of the cellulose raw material grinding method of dissociation and extraction method of each cellulose raw material of the present invention; Synthesizing cellulose microfibers through a physical process from the milled cellulose raw material; And stabilizing the cellulose microfibers by projecting ultrasonic waves onto the cellulose microfibers.

In the method for producing each of the cellulose microfibers of the present invention, in the physical process, it is preferable that the dissociated and extracted cellulose raw material is contained in the microchannel, and the dissociated and extracted cellulose raw material is flowed at a rotational speed of 1000 rpm or more. .

In the pulverization method of each of the cellulose raw materials of the present invention, it is preferable that the length of the short axis is between 1 μm and 100 μm.

Further, in the pulverizing method of the cellulose raw materials of the present invention, it is more preferable that the microchannel has a short axis length of 10 µm or more and 20 µm or less.

On the other hand, the present specification further discloses a cellulose microfiber, prepared according to the method for producing each cellulose microfiber of the present invention.

On the other hand, the present specification includes a stirrer, and a pressure controller, the cellulose raw material is crushed, homogenizing unit; A pressurizing unit for pressurizing the pulverized cellulose raw material obtained in the homogenizing unit to induce the synthesis of cellulose microfibers; And a stabilizing unit for projecting ultrasonic waves onto cellulose microfibers.

In addition, in each of the cellulose microfiber manufacturing apparatus of the present invention, the pressurizing portion, at least one or more microchannels, in which the pulverized cellulose raw material is stored or passed; And at least one rotor positioned inside the microchannel and rotating the pulverized cellulose raw material to impart shear force to the pulverized cellulose raw material.

By employing the above-described means, the present invention can be easily pulverized cellulose raw material under low temperature conditions by utilizing the expansion pressure of the sublimable material, as a result can minimize the carbonization and energy consumption of the cellulose raw material.

In addition, the manufacturing method of the cellulose microfiber of the present invention is significantly reduced energy consumed in the preparation of the cellulose raw material, it is possible to implement a low-energy process.

In addition, the apparatus for producing cellulose microfibers of the present invention can provide advantages in terms of commercial production of cellulose microfibers by allowing the general manufacturing process of cellulose microfibers to be performed through a simple structure.

The terminology used herein is for the purpose of describing particular examples only. Thus, for example, singular forms include plural forms unless the context clearly requires them to be singular. In addition, the terms "comprise" or "include" as used in the present application are used to clearly indicate that there exists a feature, step, function, component, or combination thereof described in the specification, and other features. It should be noted that it is not intended to preliminarily exclude the presence of elements, steps, functions, components, or combinations thereof.

On the other hand, unless defined otherwise, all terms used herein are to have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Accordingly, unless specifically defined herein, a particular term should not be construed in an excessively ideal or formal sense.

In the description herein, "low energy" means that all or part of the process proceeds effectively with only a small amount of energy projection as compared to the prior art in the art. In the area of the physical treatment method or the physical dissociation and extraction method on which the present invention is based, energy of about 20 KJ / mol is usually consumed to isolate or dissociate and extract the cellulose raw material. Therefore, the production method of the present invention as a low energy method means that can be implemented by supplying energy of about 20 KJ / mol effectively at low temperature without loss.

In the description of the present specification, the "cellulose raw material" includes the following materials. However, the present invention is not limited thereto, and a person of ordinary skill in the art may freely select the food for the purpose. Illustratively, microcrystalline cellulose, microbial cellulose, cellulose derived from marine or other invertebrates, mechanically produced wood pulp, chemical (dissolving) pulp, natural biomass: Other cellulose II sources such as cellulosic artificial fibers such as plant fibers, stems or hulls) and tire cords and mercerised cellulose and the like.

In addition, the cellulose raw material includes a derivative in a range that does not contradict the technical means of the present invention. As an example of the cellulose derivative of the present invention, for example, carboxylated derivatives, oxidized derivatives, esterified derivatives and the like can be considered. On the other hand, the cellulose raw material of the present invention may be provided in powder form.

Specifically, as a preferred cellulose raw material, cellulose fibers derived from wood pulp, or cellulosic biomass fibers can be considered. As an example of wood pulp, fibers from ground wood, fibers from recycled or secondary wood pulp can be considered. Both soft and hardwoods are allowed. However, bleaching of wood pulp is not a key issue.

In the description herein, "swelling agent" acts to disrupt the interaction between the crystals present in the interior of the cellulose raw material, to dissociate at least some of the bonds in the crystals, or the interactions between the crystals and the bonds within the crystals. A generic term is a substance that performs all of at least some of the breakdown. That is, in the practice of the present invention, the use of a swelling agent does not mean complete solvation of the cellulose raw material.

In addition, this invention limits the temperature conditions as mentioned later. In addition, in the practice of the present invention, the swelling agent is particularly preferably distilled water. For example, coagulation of distilled water, which is a swelling agent, needs to be limited because it can lead to non-uniform isolation of cellulose raw materials.

However, one of ordinary skill in the art may further add one or more of the swelling agents described below to promote swelling of the cellulose raw material within the scope of not impairing the core of the technical idea of the present invention. Examples of swelling agents having the properties described above include alkali metal oxides, alkali metal hydroxides (eg, potassium hydroxide, lithium hydroxide), alkaline earth metal oxides, alkaline earth metal hydroxides, alkali silicates, alkali aluminates. (alkali aluminates), alkali carbonates, alkali thiocyanates, alkaline earth thiocyanates, alkali halides (e.g. chlorides, fluorides, bromide) Aliphatic hydrocarbon amines, amines including lower aliphatic amines (eg trimethylamine, triethylamine), cupriethylenediamine, ammonia, ammonium hydroxide; Tetramethyl ammonium hydroxide; Trimethylbenzylammonium hydroxide; Lithium chloride; Tertiary amine oxides (e.g., N-methyl morpholine N-oxide), ionic liquids (e.g., 1-ethyl-3-methyl) Imidazolium acetate (1-ethyl-3-methylimidazolium acetate), urea and mixtures thereof, zinc ammonium complex, zinc chloride, copper ammonium complex, silver ammonium Silver ammonium complexes, strontium hydroxide, barium hydroxide, and the like or mixtures thereof may be considered.

As used herein, the term "sublimable material" includes both materials that sublimate directly from solid to gas and materials that vaporize from liquid to gas. As an example of the sublimable material as described above, dry ice or the like that sublimation occurs can be considered, and liquid nitrogen, liquid helium, liquid neon, liquid argon, etc., in which vaporization occurs can be considered.

In the description of the present specification, "dissociation and extraction method" means a method of isolating a cellulose raw material. In particular, the pulverization method of the present invention means that the bonds and interactions mainly between cellulose polymers are dissociated and relaxed, not dissociated bonds (ie, glycoside bonds) inside the polymer compound. On the other hand, it can be understood that the dissociation and extraction method of the present invention is mainly carried out by a physical process (ie, imposing an external force).

Hereinafter, the dissociation and extraction method of the cellulose raw material of the present invention will be described in more detail. The present specification is a cellulose raw material and a swelling agent is mixed, the first step of swelling the cellulose raw material; And a second step of adding a sublimable substance to the swollen cellulose raw material.

On the other hand, the first step of the present invention is preferably carried out at a temperature condition of more than 1 ℃ to less than 10 ℃. For example, when it is carried out at a temperature of less than 1 ℃, distilled water which is a swelling agent may be solidified. In contrast, when carried out at a temperature of 10 ° C or less, it is possible to enjoy the advantage that the hydrolysis of the glycoside bonds is substantially limited.

In particular, at a temperature of approximately 4 ° C., the volume per unit mole of distilled water as a swelling agent is minimized, so that the largest number of water molecules can penetrate the cellulose raw material. As a result, the dehydration of distilled water penetrated into the cellulose raw material in the addition step of the sublimable substance described later can be maximized, and the cellulose raw material can be more uniformly ground.

In the pulverization method of each cellulosic raw material of the present invention, the swelling agent is distilled water, and the sublimable material includes at least one material selected from the group consisting of dry ice, liquid nitrogen, liquid helium, liquid neon, and liquid argon. desirable. In particular, in the pulverization method of each cellulose raw material of the present invention, the sublimable substance is more preferably dry ice from the viewpoint of supply and storage.

Hereinafter, dry ice is described as a sublimable substance. However, this description does not necessarily mean that the sublimable material of the present invention is dry ice.

On the other hand, dry ice is added to the cellulose raw material in which the swelling agent has penetrated. The weight ratio of cellulose: water: dry ice is 98: 2: 1.2. At this time, in order to achieve uniform dispersion of the dry ice, the cellulose raw material and the dry ice are stirred at high speed. There is no particular limitation on the type of stirrer, but it may be considered to use a mixer that rotates at high speed.

For example, the mixer may mix the cellulose raw material and dry ice at a rotation speed of 500 rpm or more to 5000 rpm or less. However, a person skilled in the art may adjust the rotation speed so that the cellulose material infiltrated with the swelling agent and dry ice can be properly mixed in consideration of the characteristics of the cellulose raw material, the temperature of the swelling agent, the amount of dry ice added, and the like.

On the other hand, dry ice in contact with the cellulose raw material rapidly absorbs heat and sublimes. By sublimation, dry ice increases its volume by more than 800 times and exerts a strong expansion pressure on the cellulose raw material. In addition, by absorbing the heat generated by the high-speed rotation during the sublimation process, the temperature inside the cellulose microfiber manufacturing apparatus of the present invention can be maintained at 10 ℃ or less.

This means that the second step of the present invention is carried out under cold-high pressure conditions. In particular, by enabling the grinding of the cellulose raw material under low temperature conditions, the grinding process of the cellulose raw material of the present invention can minimize the unnecessary carbonization and recrystallization of the cellulose raw material, the formation of α-anomer.

In addition, the distilled water absorbed by the cellulose raw material decomposes at high speed, disrupts the interaction between crystals of the cellulose raw material, and dissociates the bond between the cellulose fibers or the bond inside the cellulose fiber. As a result, the cellulose raw material is isolated. In particular, when distilled water sufficiently infiltrates the cellulose raw material, uniform isolation of the cellulose raw material can be expected.

On the other hand, as described above, the pulverization process of the cellulose raw material of the present invention is carried out under low temperature-high pressure conditions. In particular, it is realized by sublimation of dry ice uniformly mixed with the cellulose raw material. Sublimation of dry ice causes shear force, impact force, etc. to be applied to a cellulose raw material more than one direction. As a result, the cellulose raw material is more densely pulverized, and the diameter and thickness of the pulverized cellulose raw material can be more uniformly reduced. That is, it can be understood that the homogenization of the cellulose raw material is made.

In addition, in the grinding method of each cellulose raw material of the present invention, it is more preferable that the first step and the second step are performed at a temperature condition of 1 ° C or more and 100 ° C or less. When carried out at a temperature of less than 1 ° C, distilled water, which is a swelling agent, may solidify. Conversely, when carried out at temperatures above 100 ° C., unnecessary hydrolysis of glycoside bonds may occur significantly. As a result, a decrease in the physical properties of the cellulose microfibers may be caused by the formation of the α-anomer.

In view of minimizing the problems as described above, it is preferable that the first and second steps are performed at a temperature condition of 1 ° C or more and 50 ° C or less, and preferably performed at a temperature condition of 1 ° C or more and 20 ° C or less. More preferably, it is most preferably carried out at a temperature condition of more than 1 ℃ to less than 10 ℃. In particular, when carried out at a temperature of less than 10 ℃ can enjoy the advantage that the hydrolysis of the glycoside bonds is virtually limited.

On the other hand, it should be noted that the cellulose raw material grinding method of the present invention, more precisely, the use of a sublimable substance (dry ice), makes it possible to uniformly grind the cellulose raw material under low temperature conditions of 10 ° C or lower. That is, the pulverization method of the cellulose raw material of the present invention may be performed at a temperature of 100 ° C. or less, but may provide additional advantages as described above. However, it is an advantage of the present invention that it can be performed at a low temperature. It should not be.

On the other hand, the present specification is a step of preparing a cellulose raw material, which is ground in accordance with any one of the cellulose raw material grinding method of the cellulose raw material grinding method of the present invention; Synthesizing cellulose microfibers through a physical process from the milled cellulose raw material; And stabilizing the cellulose microfibers by projecting ultrasonic waves onto the cellulose microfibers.

In the manufacturing method of each of the cellulose microfibers of the present invention, the physical process is a method in which dissociated and extracted cellulose raw material is contained in the microchannel, and the rotor is displaced and extracted by high speed movement of the rotor inside the microchannel. It is preferable to flow at a rotational speed of rpm or more. In the pulverization method of each of the cellulose raw materials of the present invention, it is preferable that the length of the short axis is between 1 μm and 100 μm.

On the other hand, the micro channel may include two conical members (for example, upper and lower surfaces, or left and right surfaces) installed in the same axis. For example, one member is fixed (stator) and the other is rotated at high speed (rotor). Fine unevenness may be formed on the outer surfaces of the stator and the rotor. The rotor rotates at high speed and exerts shear and impact forces on the ground cellulose raw material and causes cavitation. As a result, the pulverized cellulose raw material is primarily microfibers.

For example, the rotation speed of the rotor may be at least 1000 rpm. By satisfying the above-mentioned rotational speed, the temperature rise of the cellulose raw material ground throughout the manufacturing process of the cellulose microfibers is limited to 100 ° C. or less, and the physical properties of the cellulose microfibers due to side reactions can be prevented.

Further, in the pulverizing method of the cellulose raw materials of the present invention, it is more preferable that the microchannel has a short axis length of 10 µm or more and 20 µm or less. The smaller the shorter length of the microchannel, the lower the yield of the cellulose fine fibers. On the contrary, the greater the shorter length of the microchannel, the more uniform the fiberization of the pulverized cellulose raw material. Therefore, it is preferable to satisfy the above range in view of harmonizing yield and obtaining of uniform microfibers.

On the other hand, the present specification further discloses a cellulose microfiber, prepared according to the method for producing each cellulose microfiber of the present invention. The method for producing microfibers of the present invention does not require the addition of an acid catalyst, and is a low temperature process using a sublimable material that is virtually free of reactivity. Thus, no substituents are introduced into the cellulose microfibers, the functional groups of the cellulose are not oxidized or reduced, and carbonization is limited. As a result, unintended deterioration in thermal stability, deterioration in physical properties and the like from the cellulose microfibers of the present invention are limited.

On the other hand, the present specification includes a stirrer, and a pressure controller, the cellulose raw material is crushed, homogenizing unit; A pressurizing unit for pressurizing the pulverized cellulose raw material obtained in the homogenizing unit to induce the synthesis of cellulose microfibers; And a stabilizing unit for projecting ultrasonic waves onto cellulose microfibers.

Further, in the apparatus for producing cellulose microfibers of the present invention, there is no particular limitation on the kind of the stirrer, but it is possible to use a mixer that rotates at a high speed. The stirrer mixes the cellulose raw material (especially in the form in which the swelling agent is absorbed) and dry ice. The rotation speed of the stirrer may be between 500 rpm and 5000 rpm. If the rotational speed is less than 500 rpm, uniform mixing of the cellulose raw material and dry ice may not be made. On the contrary, when the rotation speed is 5000 rpm or more, an excessive amount of dry ice must be added to maintain the temperature condition of 100 ° C. or less, and the yield of cellulose microfibers per hour can be significantly reduced.

In addition, in the manufacturing apparatus of the cellulose microfiber of the present invention, the pressure control unit serves to control the expansion pressure generated when the sublimable material is in contact with the cellulose raw material. In particular, the pressure control unit may include a container for limiting the outflow of the expansion pressure, a nozzle installed on one surface of the container to maintain a constant pressure. The nozzle may discharge some or all of the sublimed material (vaporized material) from the inside to the outside.

Meanwhile, the homogenization unit of the present invention may further include a reservoir capable of storing and releasing a sublimable material. A sublimable material may be located in the reservoir, and the reservoir may be opened and closed in the direction of the stirrer. In particular, after the homogenizer is closed, the sublimable material that was located inside the reservoir can be dropped into the stirrer. As a result, external outflow due to sublimation or vaporization of the sublimable material is limited, so that high pressure conditions inside the homogenization part can be effectively realized.

After the cellulose raw material is pulverized in the homogenizing part, the pulverized cellulose raw material is transferred to the pressing part. In order to minimize contact with the atmosphere, a connecting portion for transferring the pulverized cellulose raw material to the pressing portion may be formed between the homogenizing portion and the pressing portion.

In other words, the connecting portion enables material movement between the homogenizing portion and the pressing portion. In addition, a door capable of adjusting the opening and closing manually or automatically may be formed at the connection part of the connection part and the homogenizer. The door is preferably closed when the stirrer is in operation, and is preferably opened when the pulverized cellulose raw material is moved.

In addition, in each of the cellulose microfiber manufacturing apparatus of the present invention, the pressurizing portion, at least one or more microchannels, in which the pulverized cellulose raw material is stored or passed; And at least one rotor positioned inside the microchannel and rotating the pulverized cellulose raw material to impart shear force to the pulverized cellulose raw material.

On the other hand, in the manufacturing apparatus of the cellulose microfiber of the present invention, the pressing portion may include one or more microchannels. The cellulose raw material ground in the microchannel may be filled. In addition, two or more microchannels may be located parallel to each other.

On the other hand, it is preferable that the length of a short axis is 1 micrometer or more and 100 micrometers or less, and it is more preferable that the length of a short axis is 10 micrometers or more and 20 micrometers or less. The smaller the shorter length of the microchannel, the lower the yield of the cellulose fine fibers. On the contrary, the greater the shorter length of the microchannel, the more uniform the fiberization of the pulverized cellulose raw material. Therefore, it is preferable to satisfy the above range in view of harmonizing yield and obtaining of uniform microfibers.

The pulverized cellulose raw material is preferably flown at a rotational speed of 1000 rpm or more inside the micro channel. By satisfying the above-mentioned rotational speed, the temperature rise of the pulverized cellulose raw material is limited, and the physical properties of the cellulose fine fibers due to side reactions can be prevented.

On the other hand, in order to achieve the above-described rotational speed, it is possible to consider a method in which the micro flow path is integrated. In addition, the micro channel may include two conical members (for example, upper and lower surfaces, or left and right surfaces) installed in the same axis. For example, one member is fixed (stator) and the other is rotated at high speed (rotor). Fine unevenness may be formed on the outer surfaces of the stator and the rotor. The rotor rotates at high speed and exerts shear and impact forces on the ground cellulose raw material and causes cavitation. As a result, the pulverized cellulose raw material is primarily microfibers.

On the other hand, in the manufacturing apparatus of the cellulose microfiber of the present invention, the stabilization unit may further include an ultrasonic wave generator for projecting the ultrasonic waves to the cellulose microfibers. In addition, the ultrasonic generator is immersed in the cellulose microfibers can effectively deliver the ultrasonic wave to the core of the cellulose microfibers. In particular, according to the delivery of ultrasonic waves, the microfiberization is further promoted and completed, so that the homogenization of the cellulose microfibers can proceed further.

{Example and Evaluation}

Hereinafter, with reference to the embodiments will be described in more detail with respect to what is claimed by the present specification. However, the embodiments and the like presented in the present specification may be modified in various ways by those skilled in the art and may have various forms, and the description of the present specification is not limited to the present disclosure but the present invention. All equivalents and alternatives falling within the spirit and scope of this document should be included.

Example 1 Dissociation of Cellulose Raw Material

Microcrystalline cellulose powder (Sigma Aldrich) was added to the stirrer and distilled water was stirred and mixed. The weight ratio of cellulose powder (in contrast, cellulose raw material) to distilled water was approximately 1 to 49. The temperature inside the stirrer was kept at 4 ° C. After the cellulose raw material and the distilled water were sufficiently mixed, the homogenization part was sealed and the cellulose raw material was stirred at about 2000 rpm. Dry ice was added to the stirring cellulose raw material to achieve a pressure condition of about 2,000 bar. The stirring time was about 10 minutes. In the grinding process of the cellulose raw material, the temperature inside the homogenization unit was maintained between about 4 ° C to 8 ° C. As a result, carbonized traces could not be found from the pulverized cellulose raw material.

On the other hand, the energy consumed to obtain the dissociated cellulose raw material was found to be about 21,000 KWh / t. This energy consumption is about one third of that of the conventional cellulose raw material grinding process.

Example 2: Microfiberization of Milled Cellulose Raw Material

The pulverized cellulose raw material was moved to the inside of the micro oil in the press section. The rotor installed inside the micro channel rotates at a speed of 1,500 rpm and realizes a pressure condition of about 2,500 bar. On the other hand, the cellulose raw material dissociated and extracted in the microchannel was microfiber for about 8 minutes. As the above process is repeated, more fine cellulose fibers can be obtained, and the cellulose fine fibers having a static viscosity of 20,000 cps can be obtained after 20 times.

Comparative Example 1

Referring to Comparative Document 1, it may be confirmed that energy of up to 70,000 KWh / t is typically consumed in order to manufacture cellulose microfibers through a physical process. Typically at least 60,000 KWh / t of energy is consumed for grinding (or homogenizing) the cellulosic raw material.

Comparative Example 2

In the same manner as in Example 1, dry ice was not added separately, and the cellulose raw material was stirred at 4,000 rpm or more. The internal temperature of the homogenizer was about 260 ° C. As a result, carbonized traces were found from the pulverized cellulose raw material.

In summary, the cellulose raw material grinding method of the present invention has advantages in view of low energy consumption, simple structure, easy supply of raw materials, and the like, compared to the conventional method. In addition, the method for producing a cellulose microfiber of the present invention has the advantage that side reactions such as carbonization of cellulose microfibers, introduction of substituents, etc. are suppressed by performing the entire process at a low temperature. As a result, the cellulose microfibers produced according to the method for producing cellulose microfibers of the present invention can be seen that the decrease in tensile strength is not observed, and maintains a uniform quality.

Claims (12)

A first step in which the cellulose raw material and the swelling agent are mixed to swell the cellulose raw material; And
And a second step of adding a sublimable material to the swollen cellulose raw material while stirring.
The swelling agent is distilled water, the sublimable material is dry ice,
The first step and the second step is performed at a temperature condition of more than 1 ℃ to less than 10 ℃,
The stirring of the second step is performed at a rotational speed of 500 rpm or more to 5000 rpm or less, dissociation and extraction method of the cellulose raw material.
delete delete delete delete Preparing a cellulose raw material according to the method for dissociating and extracting cellulose raw material of claim 1;
Synthesizing cellulose microfibers through a physical process from the dissociated and extracted cellulose raw materials; And
And stabilizing cellulose microfibers by projecting ultrasonic waves onto the cellulose microfibers.
The method of claim 6,
In the physical process, the pulverized cellulose raw material is contained in the fine flow path, and the pulverized cellulose raw material is flowed at a rotational speed of 1000 rpm, a method for producing cellulose microfibers.
The method of claim 7, wherein
The microchannel is a method for producing a cellulose microfiber, the length of the short axis is between 1 μm or more and 100 μm or less.
The method of claim 8,
The micro-channel is a method of producing a cellulose microfiber, the length of the short axis is between 10 μm or more and 20 μm or less.
Cellulose microfibers produced according to the method for producing a cellulose microfiber of claim 8.
delete delete