KR20210127342A - Method for manufacturing a microfibrillated cellulose using a household blender - Google Patents

Abstract

The present invention relates to a method for manufacturing microfibrillated cellulose (MFC) of cellulose using a household blender, wherein the microfibrillated cellulose (MFC) manufactured according to the manufacturing method of the present invention can be industrially used more usefully as the manufacturing process is simplified when compared to the prior art because the household blender is used in a physical treatment process. The method for manufacturing the microfibrillated cellulose comprises a step of blending the cellulose with the household blender.

Description

{Method for manufacturing a microfibrillated cellulose using a household blender}

The present invention relates to a method for producing microfibrillated cellulose (MFC) using a home blender.

Cellulose is the most common natural polymer on the planet found not only in most plants such as trees, cotton, and hemp, but also in animals with dry epidermis, such as mussels and mussels. It is a high molecular polysaccharide having a linear structure through 1-4 glucosidic bonds, and has a molecular weight of 4.6×10 ⁵ to 1.7×10 ⁶ . Cellulose is a structural unit that forms the skeleton of plants. It is a major component of the cell membrane of all higher plant cells, and plays a key role in maintaining high strength of plants, especially wood. Cellulose molecules having an effective diameter of about 6 to 7 Å are regular and strongly bound through hydrogen bonds to form microfibrillated or nanofibrillated celluloses with a diameter of 2 to 5 nm. and these fibers make up the cell membranes of plants.

Recently, as a new functional material, fibrillar cellulose has been used in various applications due to its chemical, physical and optical advantages. From the past, it has been commercializing biopolymer composite material additives for car body applications, barrier films for food and electronic devices, cosmetics additives, and cement additives. , flexible display substrate materials, flexible solar cell materials, electronic device encapsulants, optical devices, drug delivery, etc., the scope of application is expanding in high value-added fields.

Methods for producing such fibrillar cellulose include acid-hydrolysis, electrospinning, bacterial culture, and mechanical-physical methods. In particular, the mechanical-physical method is evaluated as the most promising technology in terms of physical properties and mass production. have.

It is an object of the present invention to provide a method for preparing fibrillar cellulose as part of a method for increasing the surface area of cellulose.

In order to achieve the above object, the present invention provides a method for producing microfibrillated cellulose comprising the step of blending the cellulose with a household blender.

In addition, the step of blending the cellulose is characterized in that the fibers of the cellulose are fibrillated through the homogenization of the cellulose sample.

In addition, the step of blending the hardwood bleached pulp (Ladelholze Bleached Kraft Pulp) is characterized in that the blending (blending) for 40 to 160 minutes.

Microfibrillated cellulose (MFC) prepared according to the manufacturing method of the present invention can be used more usefully industrially because the manufacturing process is simplified compared to the prior art because a household blender is used in the physical treatment process.

1 is a diagram showing the water retention value according to the physical treatment (blending) time of hardwood bleached pulp (LBKP).
2 is a diagram showing the results of the sedimentation test according to the physical treatment (blending) time of the hardwood bleached pulp (LBKP).
Figure 3 is a diagram showing the binding force of cellulose and Carbohydrate binding module protein according to the physical treatment (blending) time of hardwood bleached pulp (LBKP).
4 is a scanning electron microscope (SEM) analysis photograph of LBKP that has not been blended.
5 is a scanning electron microscope (SEM) analysis photograph of LBKP blended for 40 minutes.
6 is a scanning electron microscope (SEM) analysis photograph of LBKP blended for 80 minutes.
7 is a scanning electron microscope (SEM) analysis photograph of LBKP blended for 120 minutes.
8 is a scanning electron microscope (SEM) analysis photograph of LBKP blended for 160 minutes.

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

The present invention provides a method for producing microfibrillated cellulose comprising the step of blending the cellulose with a household blender.

Specifically, using a household blender, the cellulose substrate, broadleaf bleached pulp (Ladelholze Bleached Kraft Pulp), was mixed with 32000 to 42000 RPM, specifically 37000 RPM for 40 to 160 minutes, specifically 80 to 160 minutes, more specifically 160 It may include; blending (blending) for minutes to fibrillation (fibrillation).

The cellulose substrate refers to a substrate having a cellulose content of 70% (w/v) or more, and specifically, may be hardwood bleached pulp, but is not limited thereto.

In order to fibrillate existing wood kraft pulp, complex processes such as pulverization super friction, high pressure homogenization, cryogenic grinding, extrusion and steam explosion are required, whereas the present invention uses wood kraft pulp to produce microfibrillated cellulose. Because a home blender is used for manufacturing, the manufacturing process is simplified and it can be used more usefully industrially.

The term “pulp” used in the present invention refers to a collection of fibers constituting plants. Classification by raw material is first divided into wood pulp and non-wood pulp, wood pulp is further divided into softwood pulp (NP) and hardwood pulp (LP), and non-wood pulp is straw pulp and bagasse pulp. pulp), reed pulp, bamboo pulp, bast fiber pulp, rag pulp, and cotton pulp. In general, the pulp is peeled (debarking) step; a chipping step; screening step; And, it is produced through a pulping step. The pulping includes mechanical pulping and a chemical pulping method. In the present invention, kraft pulp using kraft pulping is used among chemical pulping methods.

The term "kraft pulp" used in the present invention refers to a manufacturing method using sodium sulfide (Na2S) and sodium hydroxide (NaOH) as pharmaceuticals during pulp production is called a kraft method, and refers to pulp produced using the kraft method. In the kraft method, pulping is possible regardless of the species, and high-strength pulp is produced.

"Bleached hardwood pulp" used in the present invention is a pulp produced by using hardwood as a species, and is also called hardwood or short-fiber pulp. Compared to softwood pulp, the fibers are shorter and the average fiber length is about 1 mm. It is characterized by having conduits and flexible cells in addition to wood fibers.

In addition, the blending refers to a physical treatment, and through homogenization of the sample, fibers having a long and intact fibrous structure of cellulose are converted into fibers of various sizes from fine threads or ribbons to fibers such as broad sheets. It may mean to deform the fibers to be fibrillated.

The fibrillation is to measure the water retention value of cellulose, check the sedimentation degree to check whether the assembly is formed, check the binding of cellulose and Ct CBD3 protein, or fiber saturation point), it is possible to indirectly confirm whether the surface area, which is a basic characteristic of fibrillation, has increased.

The water retention value is related to the binding force of the fibers and the cellulose surface area, and as more fibers are defibrillated, water retention increases. Therefore, it can be determined whether the surface area of cellulose is increased in the macroscale according to the water retention value.

The degree of sedimentation (sedimentation) can be confirmed through a sedimentation test, and the visible deposited layer exists as individual fibers or is entangled or incompletely separated fibers that interact with other fibers to form an assembly and visually fibers that can be observed. Therefore, it is possible to determine whether the surface area of cellulose is increased at the macro-scale according to the height of the settling of the fibers.

The C t CBD3 protein is known to be attached to the crystalline form of cellulose including CBM1, CBM2a, CBM3, CBM5, and CBM10, which are surface-binding-carbohydrate-binding modules. As the fibrillation progresses, the surface area of the cellulose increases and thus the C t CBD3 protein binding rate increases. Therefore, depending on the degree of binding of C t CBD3 protein, it can be determined whether the surface area is increased at the nanoscale of cellulose.

The fiber saturation point refers to a state in which the wood cells have absorbed the maximum amount of moisture, and as fibrillation proceeds, the swelling action of the cellulose fibers proceeds, resulting in a micropore volume (micropore volume). ) rather than the macropore volume. Therefore, it can be determined whether the surface area increases in the macroscale according to the accessible surface area according to the swelling action.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the following examples are only intended to embody the contents of the present invention, and the present invention will not be limited thereby.

<Example 1> Component Analysis of Hardwood Bleached Pulp

First, HPLC analysis was performed to analyze the components of the hardwood bleached pulp.

The method of Laboratory Analytical Procedure provided by the US Department of Energy's Renewable Energy Laboratory (Department of Energy, Nation Renewable Energy Laboratory) was referred to. After reacting hardwood bleached pulp (dry content 0.3 g) with 3 mL of 72% (w/w) sulfuric acid at 30°C for 1 hour, transfer it to a serum bottle, add 84 mL of distilled water to dilute it to 4%, and then at 121°C for an additional 1 hour. reacted. After the reaction was completed, the sample was separated from the solid using a filter, and the supernatant was neutralized to pH 6-8 with calcium carbonate. The neutralized hardwood bleached pulp was subjected to HPLC analysis. The glucan content means glucose, that is, the cellulose content.

The results are shown in Table 1. As a result of analysis of the components of hardwood bleached pulp, the content of Glucan, Xylan, Galactan, and Mannan was 69.4 % (w/v), 19.9 % (w/v), and 7 % (w/), respectively. v), 3.5 % (w/v). These results mean that the cellulose content of hardwood bleached pulp (LBKP) is about 70% (w/v). That is, it indirectly proves that a substrate containing 70% or more of cellulose is used for the production of micronized cellulose.

ingredient Glucan Xylan Galactan Mannan Content % (w/v) 69.4±0.3 19.9±0.4 7.0±0.2 3.5±0.1

<Example 2> Preparation of microfibrillated cellulose

Hardwood bleached pulp (LBKP) was blended using a home blender Vitamix TNC5200 blender (vitamix, japan) at 37000 RPM for 40, 80, 120 and 160 minutes, respectively, to prepare microfibrillated cellulose.

<Example 3> Confirmation of microfibrillation of cellulose

3-1. Determination of water retention value

In order to check whether the hardwood bleached pulp (LBKP) is microfibrillated, the water retention value of each of the samples of Example 2, that is, microfibrillated cellulose, was measured.

The water retention value (WRV) is the ratio of the percentage of water contained in the sample after centrifugation with force and time to the dry weight of the sample. Put a 70㎛ nylon cap on the 50 mL tube and cover the membrane filter with a 0.2㎛ pore size. The sample was filled on top and placed in a centrifuge. After centrifugation at 4 °C with a relative centrifugal force (RCF) of 900 g for 30 min, the samples were weighed. After that, it was dried in a dry oven at 80 °C for 24 hours and dried at 103 °C until all moisture was removed. Water retention was calculated using Equation 1 below. W _wet is the weight of the sample after centrifugation, and W _dry is the dry weight of the sample.

1 is a graph showing the water retention value according to the physical treatment (blending) time of hardwood bleached pulp (LBKP). As a negative control (0 min), untreated hardwood bleached pulp (LBKP) was used, and as a positive control, Borreggard MFC was used.

As shown in FIG. 1 , the water retention power of the control group without blending was 89% (w/w), and the water retention power of the experimental group blended for 40 minutes was 374% (w/w). It was confirmed that the cellulose sample blended for more than 40 minutes of the present invention had a significantly higher water retention power than 280% (w/w), which is the water retention power of general fibrillar cellulose. In particular, it was confirmed that the sample blended for 80 minutes or more maintained a high water retention of 400% (w/w) or more. These results mean that microfibrillated cellulose was formed from hardwood bleached pulp (LBKP) by blending the cellulose substrate, hardwood bleached pulp (LBKP).

3-2. sedimentation test

In order to check whether the hardwood bleached pulp (LBKP) has microfibrillation, a sedimentation test of each of the samples of Example 2, that is, microfibrillated cellulose, was performed.

Experiments were carried out at 0.0005 g/mL, 0.001 g/mL, 0.002 g/mL, and 0.004 g/mL. The degree of precipitation is a method that can confirm the dispersion stability of the MFC suspension. After making hardwood bleached pulp (LBKP) samples at a concentration of 0.05% 0.1% 0.2% 0.4% with a total volume of 10 mL, they were thoroughly mixed before the sedimentation test. And it was left for 48 hours to allow the precipitate to settle. After the cellulose fibers were completely submerged, the height of the sediment was measured. The results are shown in FIG. 4 . The visible precipitated layer refers to fibers that can be visually observed by forming an assembly when the cellulose fibers are microfibrillated and the separated fibers interact with other fibers.

2 is a graph showing the results of the sedimentation test according to the physical treatment (blending) time of the hardwood bleached pulp. Here, x-axis: Hs (height of sedimentation)/Ho (height before sedimentation), y-axis: means concentration.

As shown in FIG. 2 , it can be confirmed that the Hs/Ho value is significantly increased in the samples subjected to blending (40 minutes, 80 minutes, 120 minutes, and 160 minutes). Since there is a difference in the Hs/Ho values depending on the presence or absence of blending, it can be seen that the microfibrillation of the fibers is increased when the physical treatment is performed. In particular, among the samples of Example 2, the samples blended for 80, 120, and 160 minutes showed a higher sedimentation height at the same concentration than the positive control group (Borreggard MFC) at the same concentration. These results indicate that microfibrillated cellulose was formed from hardwood bleached pulp (LBKP) by blending.

In addition, the degree of suspension retention can also be confirmed through sedimentation test data. Suspension stability increases with higher Hs/Ho values. It can be seen that the suspension stability of the sample blended for 160 minutes is the highest, indicating that it has superior stability than the positive control (Borreggard MFC).

3-3. Ct CBD3 protein binding force measurement

In order to check whether the hardwood bleached pulp (LBKP) has microfibrillation, the Ct CBD3 protein binding force of each of the samples of Example 2, that is, microfibrillated cellulose, was measured.

Binding experiments were performed by adding 200 μg/mL of Ct CBD3 to the substrate for 1 mg of fibrillar cellulose. The substrate and protein were reacted with a total of 500 μL of 50 mM potassium phosphate buffer (pH 7.0) at 4 °C for 30 minutes. After reacting Ct CBD3 with the substrate, the supernatant was separated by centrifugation at 13,000 rpm and 4°C for 10 minutes. The amount of protein remaining in the supernatant without binding to the substrate through BCA was measured. The results are shown in FIG. 3 .

3 is a graph showing the binding force of cellulose and Ct CBD3 protein according to the physical treatment (blending) time of hardwood bleached pulp.

As shown in FIG. 3 , there is a difference in the binding rate of Ct CBD3 protein depending on the presence or absence of blending, which is a physical pretreatment step, so it can be seen that the microfibrillation of the fibers is increased when the physical treatment is performed. In particular, the sample blended for 120 minutes had the highest Ct CBD3 protein binding capacity. Fibrillation was confirmed through the physical pretreatment step of hardwood bleached pulp (LBKP), and this result means that microfibrillated cellulose was formed from hardwood bleached pulp (LBKP) by blending.

3-4. Accessible surface area measurement at fiber saturation point

In order to check whether or not the hardwood bleached pulp (LBKP) has microfibrillation, the accessible surface area of each of the samples of Example 2, that is, microfibrillated cellulose, was measured.

Dextran T2000 and Dextran T6 were used in the experiment. Dextran T2000 has about 56nm stokes diameter (Macropore volume) and is larger than the fiber wall, so it does not penetrate into the fiber wall. Therefore, only the water outside the fiber dilutes the dextran solution. Dextran T6 has about 3.6 nm stokes diameter (Micropore volume). Although it can penetrate into the fiber, it has a characteristic that it cannot penetrate into the fibril. Therefore, when the water in the fiber expands and comes out of the fibril, the Dextran solution is diluted. Prepare 0.1 g pulp (considering dry content) to 10% pulp concentration. Add 4.375 mL of 2% Dextran solution and react for 1 hour in a rotational mixer at 100 rpm. After 1 hour, centrifugation was performed at 3000 G for 15 minutes to prepare a supernatant, and the prepared supernatant was filtered with a 0.45 μm syringe filter and detected with an HPLC RI detector. According to Equation 2, each pore volume can be known in consideration of the concentration of dextran before and after addition to the pulp, the weight of dry fiber, and the amount of water in the pulp. After obtaining the pore volume (V ₅₆ nm , V _{3.6 nm} ), the value of the accessible surface area is calculated according to Equation 3 below. The results are shown in Table 2.

V : pore volume

W _dex : mass of dextran solution

W _water : mass of water in the sample

W _pulp : dry weight of the sample

CAC: cellulose accessibility to cellulase

V _56nm : Dextran T2000 pore volume

V _3.6nm : Dextran T6 pore volume

As shown in Table 2, it was confirmed that there was a large difference in the value of the accessible surface area according to the presence or absence of blending. In addition, in a sample subjected to blending for 80 minutes or more, a value similar to that of the control group, Borreggard MFC, was shown. These results indicate that microfibrillated cellulose was formed from hardwood bleached pulp (LBKP) by blending.

Processing time (min) 0 40 80 120 160 Borreggard MFC surface area
(Swelling Volume) 1295 2005 2435 2362 2412 2348

<Example 4> Scanning electron microscope (SEM) analysis

SEM analysis of the sample according to the blending time of the cellulose sample was performed. It can be seen that the longer the blending processing time from 0 minutes to 160 minutes, the more fibrils are generated. The results are shown in FIGS. 4 to 8 .

4 to 8, the cellulose sample (0 min) not subjected to the blending treatment has a cellulose fiber bundle structure and shows a long and intact fibrous shape. On the other hand, fibers are separated from cellulose that has been blended for 40 minutes to form fibrils or micronized fibers in a range of 29 nm to 16 nm. Accordingly, it can be confirmed that the cellulose is microfibrillated.

As described above, although specific embodiments of the present invention have been described in detail, those skilled in the art who understand the spirit of the present invention may add, change, delete, etc. other components within the scope of the same spirit, and other degenerate inventions However, other embodiments included within the scope of the present invention may be easily proposed. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention. should be interpreted as

Claims (4)

A method for producing microfibrillated cellulose, comprising the step of blending the cellulose with a household blender.
According to claim 1,
The step of blending the cellulose with a home blender is characterized in that the fibrillated fibers of the cellulose through the homogenization of the cellulose sample, microfibrillated cellulose (microfibrillated cellulose) manufacturing method.
According to claim 1,
The step of blending the cellulose with a home blender is characterized in that the blending (blending) for 40 to 160 minutes, microfibrillated cellulose (microfibrillated cellulose) manufacturing method.
Determining that the fibrillated if the water retention power of the cellulose calculated using the following Equation 1 is 280% (w/w) or more; Alternatively, if the pore volume (V) is calculated using Equation 2 below, and the calculated pore volume (V) is substituted in Equation 3 below, the accessible surface area (CAC) value of the cellulose is 2000 or more. A method of confirming fibrillation of cellulose, including the step of determining that it is fibrillated:
[Equation 1]

;

[Equation 2]

;

[Equation 3]

.

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