KR20020082246A - Process for Preparing High-Quality Hanji - Google Patents

Abstract

PURPOSE: A process of preparing Korean paper by mixing microorganism cellulose with paper mulberry, or coating a Korean paper surface with a microorganism cellulose suspension shortly after the paper making process is provided, thereby producing Korean paper improved in tensile strength, burst index, smoothness, etc.. CONSTITUTION: About 1 to 30%(w/w) of microorganism cellulose produced from microorganism is mixed with mulberry(Broussonetia kazinoki Sieb.) or 0.1 to 50g/L microorganism cellulose suspension is coated on a Korean paper surface in an amount of 10 to 1,000ml per 1m¬2 Korean paper shortly after the paper making process. The microorganism is Acetobacter such as Acetobacter xylinum BRC21(KFCC-11270), Rhizobium or Agrobacterium.

Description

Process for Preparing High-Quality Hanji

The present invention relates to a manufacturing method of high-quality Hanji. More specifically, the present invention relates to a method for producing high quality Korean paper with improved various physical properties by mixing mulberry fiber and microbial cellulose, which is the main raw material of the production of Korean paper, and an advanced Korean paper manufactured by the electric method.

Hanji manufacturing technology, which was introduced in China, has been developed into Hanji's original grassland method to suit our climate. The traditional method of making Hanji is a laborious and complicated process, and it is divided into eight main processes: making-boiling-washing and sun-tapping-tapping-paper-making (drainage) -watering-drying-trimming.

The main ingredient of Hanji is paper mulberry, which is steamed to make the bark peel off well. Peeled bark of this dried mulberry tree becomes white skin. Soak well-dried white skin soaked in clear water for one or two days. Cut the white skin into proper size, put it with lye in a pot and boil it for 4-5 hours. The lye is then washed and sun-bleached from the boiled raw material. The tea is picked by hand from the finished raw material after washing and bleaching, and then the batter is put on top of the stone and beated for 40 to 60 minutes with a bat to beat the mulberry fiber. Put the raw material from which fiber is completely loosened into a bucket and stir with a round stick to mix well with water and perform the dissociation process. After that, add the mulberry sap to the completely loose raw material and stir well again so that the fibers maintain a constant concentration throughout. Next, immerse your feet in a paper container filled with paper, or papermaking, and shake the paper back and forth to float the paper. Traditional papermaking method of Hanji is uni-knit, but recently, twin-knit, which is an improved grassing method, is used. The foot on which the wetland is placed is transferred from the foot to the sheet one by one, and the wetland is piled up with a paddle and pressed to remove moisture. Trimming is one of the finishing methods of Hanji. First, apply a thin rice paste on the surface of the paper, which is shaped like red bean or treadmill, with thin rice paste on the surface, several tens of sheets, and tapping hundreds of times, making the paper dense and smooth, increasing strength and gloss. As described above, the traditional papermaking method using only the mulberry fibers as a main raw material to produce a variety of hanji with only one mulberry fiber, the quality was excellent.

In recent years, the production of the papermaking technology has been partially improved to improve the papermaking process. In other words, when boiling white skin, chemicals such as sodium carbonate, sodium hydroxide, and sodium sulfate are used instead of lye. However, when boiled with a strong alkaline chemicals such as sodium hydroxide, there is a problem that the fiber itself is damaged, loses gloss, decreases strength and yield, and damages lipids of Hanji. In the bleaching of raw materials, it is performed by chemicals, such as bleaching powder, sodium hypochlorite, and sodium chlorite. In addition, the beating process is also carried out using a mechanical knife-type beater, the dissociation process is also carried out using a screw, and polyacrylamide or polyethylene oxide is used instead of the kneading after dissociation. In the drying method after papermaking, the paper is laid out on a dry plate made of iron plate heated with steam, and the trimming process also uses an actuator or a motor. While this modern process has the advantage of lowering the production cost of the product and enabling mass production, it is possible to add other pulp fibers in addition to Doc fiber and to a large amount of chemicals to reduce the manufacturing cost and shorten the manufacturing time. As a result, the disadvantages of excessive deterioration and decomposition of cellulose fibers, weakening the strength of Hanji, lowering tensile strength and tearing strength, and deteriorating physical properties of Hanji Oil. However, since the conventional methods require excessive production cost and production period, efforts have been made to solve the disadvantages of the improved method.

Therefore, the need to develop a method that can overcome the shortcomings of the improved Hanji manufacturing method has emerged constantly.

Therefore, the present inventors have diligently researched to develop a method for improving the properties of Hanji. As a result, microbial cellulose produced by microorganisms is mixed with mulberry fibers or the surface of Hanji is coated with a suspension of electric microbial cellulose immediately after the papermaking process. In this case, it was confirmed that the physical properties such as tensile strength, tear index, tear index, smoothness, and air permeability of the hanji can be significantly improved, thereby completing the present invention.

After all, the main object of the present invention is to provide a method for producing high-quality Hanji with improved physical properties using microbial cellulose.

Another object of the present invention is to provide a high-quality paper made by the electric method.

The manufacturing method of the advanced hanji of the present invention, in the manufacturing method of the hanji comprising the main raw material making, boiling, washing and sunburning, tapping, paper making (papermaking), draining, drying and trimming process, the main raw material making process or papermaking It is characterized by mixing the cellulose produced by the microorganisms in the process with the mulberry fibers or by coating with a suspension of electric microbial cellulose immediately after the papermaking process: the microorganisms are genus Acetobacter , genus Rhizobium or Agro. Agrobacterium genus microorganism, preferably Acetobacter genus microorganism, most preferably acetobacter xylium BRC21 (KFCC-11270). In addition, the microbial cellulose is preferably mixed with the mulberry fiber in a solid content of 1 to 30% (w / w), and when coated with a coating of 0.1 to 50g / l microbial cellulose suspension of 10 to 1000ml per square meter desirable.

The microbial cellulose used in the present invention is a cellulose produced by microorganisms, in particular, Acetobacter genus microorganisms. The primary structure of cellulose produced by microorganisms is beta 1 and 4 glucans (β-1, 4 glucan), which have the same chemical composition and molecular structure as cellulose of higher plants, but have different microstructures. Microbial cellulose is produced in the form of a gel in culture in a pure state. When the gel-like microorganism cellulose is observed under an electron microscope, very fine fibrils are sparsely entangled and have a three-dimensional network structure.

Since microcrystalline cellulose fibrils have high crystallinity, the Young's modulus is 16-18 GPa, which is very high, and can be a high strength, high elastic material (the Young's modulus is a numerical value indicating the rigidity of the material). When the gel-like microbial cellulose is washed with an alkaline solution and a bleach, the Young's modulus is increased by 30 GPa, and the microbial cellulose sheet is known to have the strongest Young's modulus among the organic sheet. On the other hand, the Young's modulus of ordinary species or polyethylene sheet is generally about 1 to 3 GPa. The average length of the fiber of the mulberry is 8.72mm and the average fiber width is 23.3㎛, whereas the thickness of microbial cellulose is only 20 ~ 50nm, which is only 1/1000 of the wood pulp. Its surface area is larger than cellulose, and thus its water holding power is large, and it is strongly bound by hydrogen bonds. Hydrogen bonds between microbial cellulose fibrils are broken when mechanical shearing force is applied in a mixer, etc. in water, so that they can be uniformly dispersed in fibrous form and become a slurry, so that they can be made of paper like ordinary pulp.

As described above, the microbial cellulose has excellent binder (binder) properties because of its high water retention, adsorptivity, and comprehensiveness, and can be used for high strength paper production, high tensile strength sheet production, and nonwoven fabric production.

A strain producing the cellulose is acetonitrile bakteo (Acetobacter) genus, Rhizopus emptying (Rhizobium) genus, and Agrobacterium (Agrobacterium) into the like is known, that in the production yield the best microorganism is aerobic and gram-negative acetonitrile bakteo jailri It is anium ( Acetobacter xylinum ). When acetobacter xylium is cultured with glucose as a substrate, cellulose is produced on the surface of the culture solution in a gel form. For mass production of microbial cellulose, shaking culture is more economical than static culture. However, in general, acetobacter xylnium is a yield that is often lower than the political culture because the cultivation of the cellulose produced by the shear force in the shaking culture is often generated. The present inventors mass-produced using acetobacter xylium BRC21 (KFCC-11270) which is genetically stable in nature and excellent in cellulose productivity.

In order to mix the microbial cellulose with the mulberry fibers or to coat the surface of the hanji with the suspension of the electric microbial cellulose immediately after the papermaking process, it must first be purified, bleached, and uniformly dispersed with fibrils in a slurry state. After recovering the cellulose gel from the stationary culture solution, it is immersed in a sodium hydroxide solution for several hours or a day to remove the cells inside the gel. Alkaline treated gels are washed several times with sufficient water, and then bleached and washed with an oxidizing agent such as sodium hypochlorite. Purified and bleached microbial cellulose gel is uniformly dispersed in fibrous form using a mixer equipped with a high speed rotary blade. Dispersed microbial cellulose is very water-retaining, it is preferable to add sufficient water when grinding.

On the other hand, when the microbial cellulose is produced by shaking culture, since the cellulose fibrils are produced in a dispersed state or aggregated state in the culture medium, not in a gel state, the culture solution is centrifuged to recover and wash the cellulose, and then the same treatment as described above is performed.

In other words, by using microbial cellulose as an additive in the production of hanji, the quality of hanji can be remarkably improved.

The microbial cellulose dispersed in the slurry state is mixed with mulberry fibers during the main raw material making process or with mulberry fibers before papermaking. At this time, the addition amount of the microbial cellulose can be mixed with the mulberry fiber in various ratios in the range of 30% or less based on the solid content, depending on the characteristics of the Korean paper to be produced, it is most preferably mixed less than 10%. In addition, even when the surface of the hanji is coated with a suspension of the microbial cellulose immediately after the papermaking process, the amount of the microbial cellulose added is 10 to 1000 ml per 1 m 2 of the microbial cellulose suspension of 0.1 to 50 g / L depending on the characteristics of the hanji to be produced. It is preferable to coat with. As such, when the microbial cellulose is mixed with the mulberry fiber, the Young's modulus is high and the fine cellulose is distributed among the relatively thick mulberry fibers, which enhances the binding between the fibers by hydrogen bonding, thereby increasing the strength of the Korean paper. In particular, the strength characteristics of Korean paper mixed with microbial cellulose under high humidity conditions were better.

Hereinafter, the present invention will be described in more detail with reference to the following examples. These examples are only for illustrating the present invention in more detail, it will be apparent to those of ordinary skill in the art that the scope of the present invention is not limited by these examples in accordance with the gist of the present invention. .

Example 1 Preparation of Hanji Mixed with Microbial Cellulose

HS medium supplemented with 2% glucose with Acetobacter xylinum BRC21 (KFCC-11270) as a carbon source (glucose 20.0 g / l, yeast extraction 5.0 g / l, bactopeptone 5.0 g / l, sodium phosphate 2.7 g / l, citric acid 1.15 g / l). That is, 100 ml HS medium was dispensed into a 500 ml Erlenmeyer flask and sterilized for 15 minutes at 120 ° C., and then inoculated with Acetobacter xylium BRC21 and incubated at 30 rpm at 150 rpm for 7 days in a large shake incubator. After incubation, the cellulose gel formed on the flask was collected, washed with tap water, immersed in 5% sodium hydroxide solution for 24 hours, and washed several times until alkali was completely removed. The cellulose gel was then immersed in 1% sodium hypochlorite solution overnight and washed until no chlorine odor was present. Then, the cellulose gel (about 99% of water) was put in a blender with the same volume of water and ground at a speed of 15000 rpm to uniformly disperse the cellulose fibrils.

In order to examine the effects of mixing microbial cellulose in the papermaking process, 0, 2, 4 or 6% of the microbial cellulose was added to the mulberry fiber at a solid content ratio. That is, the white bark of the mulberry was dried and cooked with 5% (w / v) sodium hydroxide solution at 80 ° C. for 2 hours at room temperature, followed by 7 hours using 8% (w / v) sodium hypochlorite bleach. Bleached for a while. Subsequently, the beating process is performed using a knife-type beater, the dissociation process is performed using a screw, and the microbial cellulose is made to 0%, 2%, 4%, or 6% (w / w) to the bleached pulps. Fibrils were mixed and 0.03% polyacrylamide dispersant (concentration 0.03%) was added to prepare a stock. Electric paper was made with twin feet using a foot with a diameter of 1.2 mm and a foot size of 135.5 cm × 95.5 cm, and pressed using a jack press, and then the iron plate drying rack was pressed. After drying one by one using a motor, the trimming process was performed by using a motor to manufacture hanji. Tensile strength, tear strength and burst strength of each previously manufactured paper were tested according to KS regulations (see Table 1).

Comparison of Properties of Hanji Sample Number Tensile strength (kgf) Tear index Burst index Remarks Landscape Portrait Landscape Portrait One 2.31 2.41 1.92 2.99 2.30 0% microbial cellulose compounding ratio 2 2.43 2.51 2.13 3.32 2.74 Microbial cellulose compounding ratio 2% 3 2.90 3.03 2.32 3.62 3.01 Microbial cellulose compounding ratio 4% 4 3.12 3.26 2.44 3.80 3.57 Microbial cellulose compounding ratio 6% 5 0.85 1.22 0.56 0.70 1.4 Hanji purchased on the market

As shown in Table 1, the tensile strength was significantly increased as the mixing ratio of the microbial cellulose increased.

Tensile strength is greatly influenced by the strength of fiber, fiber length, and the quantity and quality of the bond between fibers. This phenomenon is because the microbial cellulose is about 1/1000 thinner than the fiber, so the fiber surface area is increased and the fiber surface is increased. The increase in the inter-fiber bond due to the increase in the hydrogen bond by the hydroxyl group of the cellulose molecule exposed to. In addition, the fact that the strength of the microbial cellulose fibril itself is considered to be a factor. In addition, the tensile strength measurements of all the samples appeared to be higher in the longitudinal direction than in the transverse direction, which is presumably because the samples were made of so-called double twins and mainly shaken only in the front-back direction in the material.

The tear strength in tearing a paper in one direction is called tear strength, which is strongly influenced by the degree of fiber stabilization and orientation because the strength is formed by the strength of the individual fibers and the bonding force between the fibers. The samples were arranged in the transverse direction and showed a high tear strength in the longitudinal direction, and increased as the mixing ratio of microbial cellulose increased. As a characteristic of Hanji that cannot be seen in the sun, it is easy to tear at first, but it is difficult to continue tearing the torn place. This is due to the unique fiber structure of the long mulch fibers. As shown in Table 1, even when the mixing ratio of the microbial cellulose is small, it exhibits considerable resistance, indicating that the microbial cellulose further enhanced the inter-fiber cross-linking. In addition, even when the fibers are in the same orientation and not in the cross-orientation, it is considered that the deadlock is significantly increased by the action of the microbial cellulose. The fact that the control commercial product is much lower than the sample product is due to the difference in the characteristics of the wood pulp of the mulberry fiber, which is presumably due to the mixing of the wood pulp.

Burst strength is the strength at the moment of bursting as pressure increases on the surface of a certain area of paper. As shown in Table 1, as the mixing ratio of the microbial cellulose increases, it showed a tendency similar to tensile strength and tear strength, and it was found that the increase rate of the burst strength increased.

Example 2 Preparation of Hanji Coated with Microbial Cellulose

In the same manner as in Example 1, water was added to the cultured, purified and bleached microbial cellulose fibrils and suspended at a concentration of 1% (w / v) to obtain a microbial cellulose suspension. On the other hand, except that the microbial cellulose fibrils were not mixed during the production of the paper, 500 ml of the microbial cellulose suspension was uniformly coated per 1 m 2 of the Korean paper prepared in the same manner as in Example 1 and the paper-making paper. Tensile strength, tear strength, tear strength, smoothness and air permeability of Hanji prepared by the following dehydration, drying and trimming processes were tested according to KS regulations (see Table 2).

Comparison of Properties of Hanji Coated with Microbial Cellulose Sample Number Tensile strength (kgf) Tear index Burst index Smoothness (sec) Air permeability (sec) Remarks One 2.36 2.46 2.30 1.02 2.5 100% Korean paper mulberry (sample 1 in table 1) 2 2.41 2.66 2.21 3.21 3.2 Microbial Cellulose Coating Sample

As shown in Table 2, by coating microbial cellulose fibrils on the surface of the paper, the overall physical properties of the paper was improved, especially smoothness was significantly improved. Hanji is not a smooth paper compared to the original paper, but smoothness is the texture of the paper. It is one of the important factors that influence the relationship between the handwriting and printability of paper. By coating microbial cellulose fibrils on the surface of Hanji, the microbial cellulose fills the attack between the mulberry fibers and binds the mulch fibers on the surface by hydrogen bonding.

As described and demonstrated in detail in the above, the present invention provides a high-quality Hanji prepared by the method and the electric method for producing a high-quality Hanji by improving the physical properties by mixing the doc fiber and microbial cellulose, which is the main raw material of the paper. The manufacturing method of the high-quality Hanji of the present invention includes a process of mixing the cellulose produced by the microorganisms with the mulberry fiber during the main raw material making process or the papermaking process, or coating the surface of the hanji with an electric microbial cellulose suspension immediately after the papermaking process. According to the present invention, when using microbial cellulose, it will be possible to manufacture high-quality Hanji with improved physical properties and surface properties such as tensile strength, rupture strength.

Claims (6)

In the manufacturing method of Hanji, including the process of making, boiling, washing and sun-burning, tapping, papermaking, draining, drying, and trimming the main raw material, the cellulose produced by the microorganisms during the main raw material making process or the papermaking process A method for producing high-quality Korean paper, characterized in that the surface of the paper is coated with a suspension of electric microbial cellulose immediately after mixing or papermaking. The method of claim 1, Microorganisms may be from the genus Acetobacter , Rhizobium , or Agrobacterium ( Agrobacterium ) is characterized in that the microorganism Manufacturing method of high quality Hanji. The method of claim 2, The microorganism of the genus Acetobacter is acetobacter xylium BRC21 (KFCC -11270) characterized in that Manufacturing method of high quality Hanji. The method of claim 1, Microbial cellulose has a solid content of 1 to 30% (w / w) Characterized by mixing Manufacturing method of high quality Hanji. The method of claim 1, 10 to 1 m 2 of suspension of 0.1 to 50 g / l of microbial cellulose Characterized in that the coating with 1000ml Manufacturing method of high quality Hanji. High-quality Hanji prepared by the method of claim 1.