TECHNICAL FIELD
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The present invention relates to a barrier red algae fiber, and more specifically, to a barrier red algae fiber, a method for preparing the same, and a barrier coated paper and a barrier sheet comprising the same.
BACKGROUND
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Ordinary 'paper' is composed of entangled pulp fibers, so there are many spaces, allowing oxygen and water vapor to easily pass through. In other words, there is no barrier property that can prevent moisture, oxygen, and other substances from penetrating from the outside. Therefore, most packaging papers are treated with a barrier coating, and the most widely used method is to laminate polyethylene (PE), and latex coating is also being considered. Although these materials are excellent in terms of providing moisture resistance, they have the disadvantage of being difficult to biodegrade and not environmentally friendly because they are petrochemical carbon compounds. Therefore, it is urgent to discover new natural materials that can replace petrochemical raw materials and expand their uses.
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Therefore, many efforts are being made to obtain barrier properties that were previously provided by petrochemical raw materials such as polyethylene from eco-friendly materials, and cellulose, a representative eco-friendly material, can be broken down into cellulose nanofibrils (CNF), at the nanometer (nm) scale, which are considered a strong candidate for replacing petrochemical raw materials and enhancing the barrier properties of packaging materials. Cellulose nanofibrils are natural organic polymers that can be sustainably produced and are biodegradable, and are generally less than 100 nm in width and several µm in length. These cellulose nanofibers are known to have a very large aspect ratio, high specific surface area, and excellent strength properties. In addition, cellulose nanofibers are easy to prepare into films due to the strong hydrogen bonds formed between nanofibers when dried. Film-formed cellulose nanofibers are expected to be utilized as an eco-friendly barrier property-enhancing material in the packaging paper field because they can provide strong barrier properties against oxygen and liquids. However, the nanocellulose currently used is wood-derived nanocellulose, which has poor dehydration properties. Therefore, there is an urgent need to develop a biodegradable barrier material with even better dehydration and oxygen barrier properties.
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Meanwhile, red algae contain phycoerythrin and phycocyanin in addition to chlorophyll, giving them a reddish or purplish hue. They live in relatively deep water compared to other algae, are relatively small in size, and come in a wide variety of about 4,000 species. Red algae have a wider range of habitats than green algae and brown algae, growing naturally from shallow waters to deep waters where sunlight reaches. Red algae contain a lot of fibers called root-like fibers among seaweeds, and these fibers are composed of a diameter of several microns and are of an almost constant size in all red algae. In addition, red algae fibers have excellent whiteness and opacity, and the bonding ability between red algae fibers is also excellent. The crystallinity of red algae fibers is similar to that of cellulose fibers, and in particular, the thermal properties of bleached red algae fibers are superior to those of cellulose fibers. Red algae include laver, Gelidium, Gracilaria, Codium, Hypnea, Acanthopeltis, Chondrus, Polysiphonia, Bostrychia, Enteromorpha, Lithophyllum, Lithothamnion, and Grateloupia, among others. The inner gel extracts of red algae are all used as food additives, health supplements, and agar materials.
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As a technology related to barrier films,
Korean Patent Publication No. 1999-0034085 discloses a method for preparing a film as a substitute for cellophane using carrageenan biopolymer and a composition thereof, and
Korean Registered Patent No. 1770227 discloses a method for preparing a composition for an antifouling and moisture-proof barrier coating and a method for preparing an antifouling and moisture-proof barrier film using the same. However, a barrier coating method using the biodegradable seaweed fiber of the present invention, a barrier sheet comprising seaweed fiber, and a paper which is barrier-coated with seaweed fiber have not yet been disclosed.
DISCLOSURE
TECHNICAL PROBLEM
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The present invention has been made in response to the above-mentioned needs, thus the purpose of the present invention is directed to providing a barrier red algae fiber having excellent oxygen barrier properties and dehydration properties during a coating process, a method for preparing the same, and a barrier coated paper and a barrier sheet comprising the same.
TECHNICAL SOLUTION
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To achieve the above objects, the present invention provides a barrier red algae fiber comprising oval red algae fibers having a cross-sectional major axis length of 50 to 500 µm.
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According to an exemplary embodiment of the present invention, the fiber wall thickness of the oval red algae fibers may be 50 to 500 nm.
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In addition, the oval red algae fibers may be included in 50 wt% or more of the total weight of the barrier red algae fiber.
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In addition, the barrier red algae fiber is formed by red algae, and the red algae may comprise one or more selected from Eucheuma cottonii, Eucheuma spinosum and Gracilaria.
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In addition, the present invention provides a method for preparing a barrier red algae fiber, comprising: (1) adding 1,000 to 3,000 parts by weight of water to 100 parts by weight of a mixture of 0.1 to 5.0 wt% of sulfuric acid and 95 to 99.9 wt% of red algae, reacting the mixture at 60 to 120°C for 1 to 5 hours to remove carrageenan or agar and obtaining a remaining red algae residue; and (2) adding 400 to 600 parts by weight of water and 0.5 to 5.0 parts by weight of a bleaching agent to 100 parts by weight of the red algae residue obtained at above (1), adjusting pH between 3 and 5, and then reacting the red algae residue at 60 to 95°C for 0.5 to 5 hours to bleach and wash it, thereby obtaining the barrier red algae fiber.
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According to an exemplary embodiment of the present invention, the bleaching agent may be one or more selected from chlorine dioxide, sodium hypochlorite, chlorine, ozone and oxygen.
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In addition, the present invention provides a barrier coated paper comprising, a paper; and a barrier coating layer containing the barrier red algae fiber, which is coated on at least a portion of a surface of the paper.
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According to an exemplary embodiment of the present invention, the barrier coating layer may further comprise a polymer, and the barrier coating layer may comprise 10 to 99 wt% of the polymer and 1 to 90 wt% of the barrier red algae fiber.
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In addition, the polymer may comprise one or more selected from PVA (Poly vinyl alcohol), starch, nanocellulose, chitin, PLLA (Poly-L-Lactic Acid), sc-PLA (Stereo Complex Polylactic Acid), PHB (Poly-(3-hydroxy buthyrate)), PBS (Poly Butylene Succinate), PCA (Polycaprolactone) and PGA (Poly glycolic acid).
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In addition, the barrier coating layer may have a basis weight of 1 to 100 g/m2.
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In addition, the barrier coating layer further may comprise one or more selected from PAM (Poly amidoamine), a wet strength agent and a hydrophobic agent.
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In addition, the wet strength agent may comprise one or more of epoxy emulsion and epichlorohydrin, and the hydrophobic agent comprises one or more selected from AKD (alkyl ketene dimer), ASA (alkenyl succinic acid) and rosin.
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In addition, the prevent invention provides a barrier sheet comprising the barrier red algae fiber.
ADVANTAGEOUS EFFECTS
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To achieve the above objects, a barrier red algae fiber of the present invention, a method for preparing the same, and a barrier coated paper and a barrier sheet comprising the same have oxygen barrier properties and dehydration properties during a coating process that are superior to those of conventional wood-derived nanocellulose.
BRIEF DESCRIPTION OF THE DRAWING
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- FIG. 1 shows a flow chart of the biodegradable barrier coating method of the present invention.
- FIG. 2 shows an electron microscope photograph of Eucheuma cottonii fibers (A), the results of confirming the thickness of Eucheuma cottonii fibers by scanning probe microscopy (B), and cylindrical nanocellulose of wood cellulose (C), A shows the fiber thickness of 200 nm, in which two fiber walls of about 100 nm each overlap, B shows the surface height of the sample holder, and C shows that wood cellulose is cylindrical rather than oval and that the width of the fibrils is about 100 nm.
- FIG. 3 compares Eucheuma cottonii fiber and cellulose fiber, where (A) shows the XRD patterns of Eucheuma cottonii fiber and cellulose (softwood fiber), which is a bleached pulp from coniferous trees, and (B) shows the HPLC analysis results of sugar content (fructose, glucose, and xylose) in Eucheuma cottonii fiber and cellulose.
BEST MODES FOR CARRYING OUT THE INVENTION
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Hereinafter, with reference to the attached drawings, exemplary embodiments of the present invention will be described in detail so that persons of ordinary skill in the art can easily practice the present invention. The present invention may be implemented in various different forms and is not limited to the exemplary embodiments described herein. In the drawings, in order to clearly describe the present invention, parts that are not related to the description are omitted, and the same reference numerals are added to the same or similar components throughout the specification.
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The barrier red algae fiber according to the present invention is implemented by comprising oval red algae fibers.
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In this case, the oval red algae fibers have an oval shape as shown in FIG. 2.
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In addition, the oval red algae fibers may have a cross-sectional major axis length of 50 to 500 µm, and preferably, a cross-sectional major axis length of 60 to 450 µm. If the cross-sectional major axis length of the oval red algae fibers is less than 50 µm, the dehydration property may be reduced during the coating process, and if the cross-sectional major axis length of the oval red algae fibers exceeds 500 µm, the oxygen barrier property may be reduced.
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Meanwhile, the term "major axis" used in the present invention refers to the axis having the longest length in a cross section.
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In addition, the fiber wall thickness of the oval red algae fibers may be 50 to 500 nm, and preferably, the fiber wall thickness may be 60 to 450 nm. If the fiber wall thickness of the oval red algae fibers is less than 50 nm, the dehydration property may be reduced during the coating process, and if the fiber wall thickness of the oval red algae fibers exceeds 500 nm, the oxygen barrier property may be reduced.
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In addition, the oval red algae fibers may be included in 50 wt% or more of the total weight of the barrier red algae fiber, preferably 60 wt% or more of the total weight of the barrier red algae fiber, and more preferably 70 wt% or more of the total weight of the barrier red algae fiber. If the oval red algae fibers are included in less than 50 wt% of the total weight of the barrier red algae fiber, the oxygen barrier property and the dehydration property during the coating process may deteriorate.
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In addition, the barrier red algae fiber according to the present invention is prepared by comprising: (1) adding 1,000 to 3,000 parts by weight of water to 100 parts by weight of a mixture of 0.1 to 5.0 wt% of sulfuric acid and 95 to 99.9 wt% of red algae, reacting the mixture at 60 to 120°C for 1 to 5 hours to remove carrageenan or agar and obtaining a remaining red algae residue; and
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(2) adding 400 to 600 parts by weight of water and 0.5 to 5.0 parts by weight of a bleaching agent to 100 parts by weight of the red algae residue obtained at above (1), adjusting pH between 3 and 5, and then reacting the red algae residue at 60 to 95°C for 0.5 to 5 hours to bleach and wash it, thereby obtaining the barrier red algae fiber.
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In this case, it is preferable that the red algae comprise one or more selected from Eucheuma cottonii, Eucheuma spinosum and Gracilaria, but is not limited thereto.
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In addition, it is preferable that the bleaching agent is one or more selected from chlorine dioxide, sodium hypochlorite, chlorine, ozone and oxygen, more preferably chlorine dioxide or sodium hypochlorite, and even more preferably chlorine dioxide, which may be more advantageous in achieving the purpose of the present invention.
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In addition, the present invention provides barrier coated paper comprising, a paper; and a barrier coating layer containing the barrier red algae fiber, which is coated on at least a portion of a surface of the paper.
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In this case, the barrier coating layer may further comprise a polymer, and the barrier coating layer comprises 10 to 99 wt% of the polymer and 1 to 90 wt% of the barrier red algae fiber. As the polymer and the barrier red algae fiber satisfy the above content range, it may be more advantageous in achieving the purpose of the present invention.
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The polymer preferably comprises one or more selected from among PVA (Poly vinyl alcohol), starch, nanocellulose, chitin, PLLA (Poly-L-Lactic Acid), sc-PLA (Stereo Complex Polylactic Acid), PHB (Poly-(3-hydroxy buthyrate)), PBS (Poly Butylene Succinate), PCA (Poly caprolactone) and PGA (Poly glycolic acid), but is not limited thereto.
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Meanwhile, the barrier coating layer can be formed by mixing the polymer and the barrier red algae fiber and coating the paper surface.
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In this case, before mixing the polymer and the barrier red algae fiber, mixing hydrogen peroxide and the barrier red algae fiber, adjusting pH, and then heat-treating to perform secondary bleaching.
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In this case, the secondary bleaching can be performed by mixing 0.5 to 5.0 wt% of hydrogen peroxide and 95 to 99.5 wt% of the barrier red algae fiber, the pH may be adjusted to a range of 10 to 13, and the heat treatment can be carried out at a temperature of 60 to 95°C for 0.5 to 5 hours.
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Meanwhile, the barrier coating layer may have a basis weight of 1 to 100 g/m2.
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In addition, the barrier coating layer may further comprise one or more selected from PAM (Poly amidoamine), a wet strength agent, and a hydrophobic agent. The wet strength agent may comprise one or more selected from epoxy emulsion, and epichlorohydrin, and the hydrophobic agent may comprise one or more selected from AKD (alkyl ketene dimer), ASA (alkenyl succinic acid), and rosin, but is not limited thereto.
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Meanwhile, the present invention provides a barrier sheet comprising the barrier red algae fiber.
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The barrier coating layer may be formed solely of the barrier red algae fiber, or may be formed by comprising a predetermined polymer and the barrier red algae fiber.
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According to an exemplary embodiment of the present invention, the barrier sheet may further comprise a polymer, and in this case, the barrier sheet may comprise 10 to 99 wt% of the polymer and 1 to 90 wt% of the barrier red algae fiber described. When the polymer and the barrier red algae fiber satisfy the above content range, it may be more advantageous to achieve the purpose of the present invention.
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The polymer preferably comprises one or more selected from PVA (Poly vinyl alcohol), starch, nanocellulose, chitin, PLLA (Poly-L-Lactic Acid), sc-PLA (Stereo Complex Polylactic Acid), PHB (Poly-(3-hydroxy buthyrate)), PBS (Poly Butylene Succinate), PCA (Poly caprolactone) and PGA (Poly glycolic acid), but is not limited thereto.
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Meanwhile, before mixing the polymer with the barrier red algae fiber, hydrogen peroxide and the barrier red algae fiber can be mixed, followed by pH adjustment and heat treatment to perform secondary bleaching.
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In this case, the secondary bleaching can be performed by mixing 0.5 to 5.0 wt% of hydrogen peroxide and 95 to 99.5 wt% of the barrier red algae fiber, the pH may be adjusted to a range of 10 to 13, and the heat treatment can be carried out at a temperature of 60 to 95°C for 0.5 to 5 hours.
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Meanwhile, the barrier sheet may have a basis weight of 1 to 100 g/m2.
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In addition, the barrier sheet may further comprise one or more selected from PAM (Poly amidoamine), a wet strength agent, and a hydrophobic agent. The wet strength agent may comprise one or more selected from epoxy emulsion, and epichlorohydrin, and the hydrophobic agent may comprise one or more selected from AKD (alkyl ketene dimer), ASA (alkenyl succinic acid), and rosin, but is not limited thereto.
MODES FOR CARRYING OUT THE INVENTION
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Hereinafter, the present invention will be described in more detail through examples. The following examples specially illustrate the present invention, and it is obvious to those persons of ordinary skill in the art that the scope of the present invention is not limited by following examples.
[Example]
Example 1-1. Preparation of barrier red algae fiber (Eucheuma cottonii fiber)
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Eucheuma cottonii fiber (barrier red algae fiber) was prepared by the preparation method according to the flow chart disclosed in FIG. 1.
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a. 300 g of dried Eucheuma cottonii, a red algae fiber, was added to 6,000 g of water so that the weight ratio was 20:1 (water: Eucheuma cottonii), and then 0.3 wt% of sulfuric acid was added based on the weight ratio of Eucheuma cottonii. After that, the temperature was increased for 30 minutes and the reaction was performed at 100°C for 3 hours, and then carrageenan was sufficiently extracted using a 200-mesh screen, and the remaining residue was referred to as 'Eucheuma cottonii residue (red algae residue)'.
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b. After adjusting the weight ratio of the water:Eucheuma cottonii residue to 5:1, chlorine dioxide was added at 2 wt% based on the dry weight of the Eucheuma cottonii residue, and the pH was adjusted to 3.5 with acetic acid. After that, the reaction was performed at a temperature of 90°C for 1 hour and 30 minutes to bleach the Eucheuma cottonii residue, and the washed material was referred to as 'Eucheuma cottonii fiber (barrier red algae fiber)'.
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In Example 1 of the present invention, it was confirmed from the XRD results and sugar analysis results of the Eucheuma cottonii fiber that the Eucheuma cottonii is composed of cellulose (FIG. 3), and 'cellulose fiber' can also be obtained from the remaining solid content after extracting agar from Gracilaria.
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The prepared barrier red algae fiber contained 80 wt% of oval red algae fibers having a cross-sectional major axis length of 50 to 500 µm and a fiber wall thickness of 50 to 500 nm.
Example 1-2
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Prepared in the same manner as in Example 1-1, except that Eucheuma cottonii was changed to Gracilaria to prepare a barrier red algae fiber. The prepared barrier red algae fiber contained 70 wt% of oval red algae fibers having a cross-sectional major axis length of 50 to 500 µm and a fiber wall thickness of 50 to 500 nm.
Comparative Example 2-1
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Prepared in the same manner as in Example 1-1, except that red algae Eucheuma cottonii was changed to red algae Gelidium to prepare a barrier red algae fiber. The prepared barrier red algae fiber was a cylindrical fiber having a major axis length of 500 to 800 µm and a fiber thickness of 1,000 to 2,200 nm.
Comparative Example 2-2
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Nanocellulose was prepared by passing 1.5% concentration of hardwood bleached pulp through a super masscolloidor 60 times, and the obtained nanocellulose was a cylindrical fiber with a major axis of 8.2 µm and a fiber width of 35.2 nm.
Preparation Examples 1-1 to 1-2 and Comparative Preparation Examples 1-1 to 1-2. Preparation of Barrier Sheets
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Using the fibers prepared in Example 1-1, Example 1-2, Comparative Example 2-1, and Comparative Example 1-2, a barrier sheet having a basis weight of 10 g/m2 and 10 g per square meter was prepared on a cellulose acetate membrane (0.45 µm pore size, HYUNDAI MICRO, Republic of Korea) filter.
Experimental Example 1: Oxygen permeability (OP) and dehydration analysis
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For the barrier sheets prepared in Preparation Example 1-1 to 1-2 and Comparative Preparation Examples 1-1 to 1-2, oxygen permeability (OP) was measured. The oxygen transmission rate was measured using an ultra-precision oxygen analyzer (OX-TRAN Model 2, MOCON, USA) at 23°C, 1 atm, and 0 relative humidity for 24 hours. In order to compensate for the barrier sheet thickness, the oxygen permeability was calculated by dividing the oxygen transmission rate by the sheet thickness.
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In addition, the dehydration was analyzed by measuring the time it took until dehydration no longer occurred when a 5 g/m2 barrier sheet was prepared by applying the same vacuum pressure on a cellulose acetate membrane (0.45 µm pore size, HYUNDAI MICRO, Republic of Korea) filter.
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The results are shown in Table 1 below.
[Table 1] | Sample | OP(oxygen permeability) Cm3·µm/m2·day·atm | Dehydration time(seconds) |
| Preparation Example 1-1 | 95 | 30.4 |
| Preparation Example 1-2 | 129 | 37.8 |
| Comparative Preparation Example 1-1 | 1237 | 42.6 |
| Comparative Preparation Example 1-2 | 234 | 342.1 |
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As shown in the Table 1, Preparation Examples 1-1 and 1-2, which all satisfy the major axis length, fiber wall thickness, and content of the oval red algae fiber of the present invention, have significantly lower oxygen permeability than Comparative Preparation Example 1-1, which exceeds the cross-sectional major axis length and the fiber wall thickness range and uses cylindrical fibers, and have significantly faster dehydration times than Comparative Preparation Example 1-2, which falls below the cross-sectional major axis length and the fiber wall thickness range and uses cylindrical fibers.
Preparation Example 2. Coating 5g of Eucheuma cottonii Fiber on a coated base paper
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60 wt% of the Eucheuma cottonii fibers prepared n Example 1-1 and 40 wt% of PVA (polyvinyl alcohol) were mixed, and then coated on a coated base paper (coated base paper supplied by a domestic M paper company with a basis weight of 50 g/m2. Hereinafter, coated base paper) using a coating bar so that the weight of the coating layer became 5 g per square meter on a dry basis, and then dried.
Preparation Example 3. Coating 10 g of Eucheuma cottonii fiber on a coated base paper
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60 wt% of the Eucheuma cottonii fibers prepared in Example 1-1 and 40 wt% of PVA (polyvinyl alcohol) were mixed, and then coated on a coated base paper using a coating bar so that the weight of the coating layer became 10 g per square meter on a dry basis, and then dried.
Comparative Preparation Example 2. Preparation of hardwood bleached pulp barrier sheet 1
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Hardwood bleached pulp was refined using a valley beater until it reached the Canadian standard freeness of 510 ml, and a barrier sheet of 20 g per square meter was prepared using the same method as Preparation Example 1-1.
Comparative Preparation Example 3. Preparation of hardwood bleached pulp barrier sheet 2
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Hardwood bleached pulp was refined using a valley beater until it reached the Canadian standard freeness of 95 ml, and a barrier sheet of 20 g per square meter was prepared using the same method as Preparation Example 1-1.
Comparative Preparation Example 4. Preparation of Microfibrils and Nanocellulose
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Using the refined hardwood fibers of Comparative Preparation Example 3 and additionally repeating the refining 20 times using a super masscolloidor, cylinder-shaped microfibrils (cellulose microfibril. CMF) having a fibril length of 25.5 µm and an average fibril width of 185 nm were prepared.
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In addition, using the refined hardwood fibers of Comparative Preparation Example 3 and additionally repeating the refining 60 times using a super masscolloidor, cylinder-shaped nanocellulose (cellulose nano-fibrils, CNF) having a fibril length of 7.6 µm and an average fibril width of 45 nm were prepared.
Comparative Preparation Example 5. Preparation of a barrier sheet 10 g per square meter using CMF
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A barrier sheet 10 g per square meter was prepared on nanofilter using the CMF prepared in Comparative Preparation Example 4.
Comparative Preparation Example 6. Preparation of a barrier sheet 10 g per square meter using CNF
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A barrier sheet 10 g per square meter was prepared on a nanofilter using the CNF prepared in Comparative Preparation Example 4.
Comparative Preparation Example 7. Coating 10 g of CMF on a coated base paper
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After mixing 60 wt% of the dried CMF prepared in Comparative Preparation Example 4 and 40 wt% of PVA (polyvinyl alcohol), the coating layer was coated on the coated base paper using a coating bar so that the weight of the coating layer became 10 g per square meter on a dry basis, and then dried.
Comparative Preparation Example 8. Coating 10 g of CNF on a coated base paper
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60 wt% of the dried CNF prepared in Comparative Preparation Example 4 and 40 wt% of PVA (polyvinyl alcohol) were mixed, and then coated on the coated base paper using a coating bar so that the weight of the coating layer became 10 g per square meter on a dry basis, and then dried.
Comparative Preparation Example 9. Preparation of film
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In an extruder (Multi-Layer T-die Extrusion Film Production Line, Hankook EM, Korea), PLA (stereoisomer of 1.2-1.6% D-isomer lactide (PLA-4032D) and an average molecular weight of 220 kDa) was heated at 160 ~ 180°C, and then a film of 10 g per square meter was prepared.
Comparative Preparation Example 10. Coated Base Paper
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Coated base paper of 50 g per square meter was supplied from a domestic company M and used.
Experimental Example 2. Analysis of oxygen permeability (OP)
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The components of the Preparation Examples 1-1, 2, 3 and Comparative Preparation Examples 2 to 10 and their oxygen permeability were measured (measured using the oxygen permeability measurement method of Experimental Example 1).
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Table 2 shows the results of the oxygen permeability (OP) of the film. Considering that the oxygen permeability of PVDC (polyvinylidene chloride), a polymer barrier film with excellent oxygen permeability, is 10 to 300 cm
3·
µm/m
2· day· atm, it was determined that biodegradable materials, Eucheuma cottonii fiber (Preparation Example 1-1) and CNF (Comparative Preparation Example 6), could function as excellent oxygen gas barriers, and in contrast, the hardwood fiber (Comparative Preparation Example 2, Comparative Preparation Example 3) barrier sheets that underwent a lot of refining and PLA (Comparative Preparation Example 9) films had very high oxygen permeability, and it was confirmed that CMF (Comparative Preparation Example 5) also did not function as an excellent barrier.
[Table 2] | Oxygen permeability of Barrier sheet or film |
| Sample | type | form | OP(oxygen permeability) cm3·µm/m2 ·day·atm |
| Preparation Example 1-1 | Eucheuma cottonii fiber | Barrier sheet 10g/m2 | 95 |
| Comparative Preparation Example 2 | Hardwood pulp 510ml CSF | Barrier sheet 20g/m2 | > 10,000 |
| Comparative Preparation Example 3 | Hardwood pulp 95ml CSF | Barrier sheet 20g/m2 | > 10,000 |
| Comparative Preparation Example 5 | CMF | Barrier sheet 10g/m2 | 487 |
| Comparative Preparation Example 6 | CNF | Barrier sheet 10g/m2 | 153 |
| Comparative Preparation Example 9 | PLA | film 10g/m2 | 17,792 |
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Table 3 shows that when Eucheuma cottonii fiber (Preparation Example 3) and CNF were coated on the coated base paper (Comparative Preparation Example 8) to 10 g/m
2, it could act as an excellent oxygen barrier like a PVDC film. However, when a small amount of Eucheuma cottonii fiber was coated, it showed slightly higher oxygen permeability than PVDC, as in Preparation Example 2. In contrast, CMF (Comparative Preparation Example 7) still showed significantly higher oxygen permeability than PVDC.
[Table 3] | Oxygen permeability after coating on 50 g/m2 of coated base paper |
| Sample | type | form | OP(oxygen permeability) cm3·µm/m2 ·day·atm |
| Preparation Example 2 | Eucheuma cottonii fiber, PVA | coating 5g/m2 | 318 |
| Preparation Example 3 | Eucheuma cottonii fiber, PVA | coating 10g/m2 | 56 |
| Comparative Preparation Example 7 | CMF, PVA | coating 10g/m2 | 855 |
| Comparative Preparation Example 8 | CNF, PVA | coating 10g/m2 | 128 |
| Comparative Preparation Example 10 | Chemical pulp coated base paper | 50g/m2 | >10,000 |
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As described above, it was confirmed that Eucheuma cottonii fiber and CNF can act as excellent oxygen barriers. However, in order to prepare CNF, not only must bleached wood pulp be prepared first, but also a lot of energy must be invested to prepare nanocellulose. In contrast, Eucheuma cottonii fiber has the advantage of requiring less energy because it can be prepared with a simple bleaching process.
Experimental Example 3. Dehydration Analysis
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In order to apply biodegradable films or coating materials as packaging materials, water must be used as a medium. However, if the dehydration speed of the water used as a medium is delayed, not only will the preparation speed be slowed down when preparing the film, but it will also be difficult to coat at a high concentration. Therefore, it was confirmed whether the dehydration was excellent.
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The dehydration experiment was measured as the time required until dehydration no longer occurred when a barrier sheet having a weight of 5 g/m2 was prepared under the same vacuum pressure on a cellulose acetate membrane (0.45 µm pore size, HYUNDAIMICRO, Republic of Korea) filter.
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As the results of the dehydration analysis are disclosed in Table 4, CMF (Comparative Preparation Example 5) or CNF (Comparative Preparation Example 6) dehydrated very slowly, so there is a high possibility that product production will inevitably be disrupted unless special equipment or a lot of drying energy is used.
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On the other hand, Eucheuma cottonii Fiber has a dehydration property similar to those of hardwood pulp that has undergone extensive refining, so it was confirmed that it can be prepared using existing papermaking machines, achieving high productivity and reduced drying energy consumption.
[Table 4] | Dehydration characteristics of biodegradable barrier raw materials |
| Sample | reference | Dehydration time(seconds) |
| Eucheuma cottonii fiber | Preparation Example 1-1 | 30.4 |
| Hardwood pulp 95 ml CSF | Comparative Preparation Example 3 | 29.4 |
| CMF | Comparative Preparation Example 5 | 189.5 |
| CNF | Comparative Preparation Example 6 | 243.7 |
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Although one example of the present invention has been described above, the spirit of the present invention is not limited to the example presented in this specification, and those skilled in the art who understand the spirit of the present invention will be able to easily suggest other examples by adding, changing, deleting, or adding components within the scope of the same spirit, but this will also be considered to fall within the spirit of the present invention.