Barrier Red Algae Fiber, Manufacturing Method Therefor, and Barrier Coated Paper and Barrier Sheet Comprising Same

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.

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.

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 um 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.

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,andamong others. The inner gel extracts of red algae are all used as food additives, health supplements, and agar materials.

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.

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.

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.

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.

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.

In addition, the barrier red algae fiber is formed by red algae, and the red algae may comprise one or more selected fromand

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.

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.

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.

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.

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).

In addition, the barrier coating layer may have a basis weight of 1 to 100 g/m.

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.

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.

In addition, the prevent invention provides a barrier sheet comprising the barrier red algae fiber.

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.

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.

The barrier red algae fiber according to the present invention is implemented by comprising oval red algae fibers.

In this case, the oval red algae fibers have an oval shape as shown in.

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.

Meanwhile, the term “major axis” used in the present invention refers to the axis having the longest length in a cross section.

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.

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.

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

(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.

In this case, it is preferable that the red algae comprise one or more selected fromandbut is not limited thereto.

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.

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.

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.

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.

Meanwhile, the barrier coating layer can be formed by mixing the polymer and the barrier red algae fiber and coating the paper surface.

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.

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.

Meanwhile, the barrier coating layer may have a basis weight of 1 to 100 g/m.

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.

Meanwhile, the present invention provides a barrier sheet comprising the barrier red algae fiber.

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.

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.

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.

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.

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.

Meanwhile, the barrier sheet may have a basis weight of 1 to 100 g/m.

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.

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.

fiber (barrier red algae fiber) was prepared by the preparation method according to the flow chart disclosed in.

a. 300 g of drieda red algae fiber, was added to 6,000 g of water so that the weight ratio was 20:1 (water:), and then 0.3 wt % of sulfuric acid was added based on the weight ratio ofAfter 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 ‘residue (red algae residue)’.