Method for manufacturing paper-making filler using mixed solution of organic fiber and inorganic compound and use thereof

Abstract

The present disclosure relates to a method for manufacturing a paper-making filler using a mixed solution of an organic fiber and an inorganic compound, and a use thereof. The paper including the paper-making filler manufactured by the manufacturing method according to the present disclosure has greatly improved bulk compared to paper using an existing ground calcium carbonate filler, thus exhibiting excellent breaking length and superior smoothness. With such characteristics, high-quality paper can be produced even when using a larger amount of filler than ground calcium carbonate, thereby enhancing economic efficiency, reducing the amount of organic fiber used, and achieving energy savings in drying.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of PCT / KR2024 / 009859, filed Jul. 10, 2024, which claims the benefit of foreign priority from Korean Patent Application No. 10-2024-0089038 filed Jul. 5 2024 and Korean Patent Application No. 10-2023-0092212 filed Jul. 17, 2023, the entire contents of each of which are incorporated herein by reference.FIELD

[0002] The present disclosure relates to a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound, and a use thereof.BACKGROUND

[0003] The raw materials used for manufacturing printing paper include wood pulp, fillers, and other additives. Among these, wood pulp is used as the main raw material, and next, the content of the filler is high. The filler is also used to improve paper qualities such as opacity, brightness, and printability, but because the price of the filler is lower compared to wood pulp, a cost-saving effect can also be expected due to the replacement of pulp.

[0004] Recently, in the paper industry, as the price of not only pulp raw materials but also oil is on an increasing trend, the development of technology for the efficient utilization of fillers, which are not only cheaper than pulp but also advantageous compared to pulp in terms of drying load, can be said to be a very important task. However, because these fillers have disadvantages such as hindering the formation of hydrogen bonds between fibers and reducing the tensile strength and stiffness of the paper, the use of fillers has been limited. To overcome problems such as the above, various measures have been sought. To prevent a decrease in paper strength while increasing the filler content, many technologies such as a mixture of pulp and filler (fiber-filler composite), preflocculation, lumen loading, and hybrid calcium carbonate have been developed and have also been applied.

[0005] For example, the pre-flocculation technology refers to a technology that forms stabilized preflocs having a uniform size by mixing calcium carbonate and an ionic polymer to cause the calcium carbonate particles to form aggregates, and then forming a strong vortex. These preflocs are used as a raw material for papermaking, and when paper is manufactured by adding the preflocs to the raw material for papermaking, paper having a higher tensile strength than paper using ordinary calcium carbonate can be manufactured. However, its use is being limited because the bulk does not increase.

[0006] As conventional technologies for manufacturing a filler for papermaking, Korean Laid-open Patent Publication No. 2009-0040682 discloses a method for manufacturing paper to which filler pre-flocculation using amphoteric polyacrylamide is applied; Korean Laid-open Patent Publication No. 2005-0023824 discloses a method for manufacturing paper using a cationic starch; and Korean Laid-open Patent Publication No. 2015-1510313 discloses a method for manufacturing hybrid calcium carbonate in which calcium carbonate and a calcium compound are pre-flocculated with an ionic polymer, and then carbon dioxide is injected to cause the calcium carbonate and newly generated calcium carbonate to aggregate. However, a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound of the present disclosure and a use thereof have not yet been disclosed.SUMMARY

[0007] In one embodiment, the present disclosure provides a method for preparing a filler for papermaking, comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.

[0008] In another embodiment, the present disclosure provides a method for preparing a filler for papermaking, comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.DETAILED DESCRIPTION

[0009] The present disclosure has been devised in response to needs such as those described above, and the present disclosure provides a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound, and a use thereof, and the present disclosure was completed by confirming that paper manufactured using the filler prepared by the filler preparation method of the present disclosure has superior bulk and breaking length compared to paper manufactured by a conventional preparation method.

[0010] To achieve the above object, the present disclosure provides a method for preparing a filler for papermaking, comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.

[0011] According to an Example of the present disclosure, the step (1) may comprise: (1-1) a step of preparing a mixed solution having a solids content of 1 to 60 wt % by mixing organic fibers and an inorganic compound in a weight ratio of 1:5 to 100, and then adding water; and (1-2) a step of preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %, by grinding the mixed solution. In addition, the inorganic compound may be one or more selected from calcium carbonate (CaCO3), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), magnesium carbonate (MgCO3), gypsum, kaolin, calcined clay, talc, perlite, diatomaceous earth, zinc carbonate, lithium carbonate, magnesium hydroxide, and aluminum trihydrate.

[0012] In addition, the calcium carbonate may be one or more selected from ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC).

[0013] In addition, the fiber fibril may comprise one or more selected from cellulose and chitin.

[0014] In addition, the ionic polymer may be one or more selected from an anionic polymer and a cationic polymer.

[0015] In addition, the anionic polymer may be one or more selected from a polysaccharide, a protein, polyvinyl alcohol, polyvinyl acetate, a cellulose derivative, epoxy acrylate, polyester, polyurethane, polyester acrylate, polyether acrylate, a polyolefin dispersion, polyamide, a vinyl copolymer, and polyacrylate.

[0016] In addition, the cationic polymer may be one or more selected from a polyamidoamine-epihalohydrin polymer, a polyalkyldiallylamine-epihalohydrin polymer, polyethyleneimine, polyacrylamide, polyamine, polyvinylamine, and a cationic starch.

[0017] In addition, in the step (2), the amount of the ionic polymer added may be 0.01 to 10 parts by weight of one or more kinds of ionic polymers with respect to 100 parts by weight of the mixed aqueous solution.

[0018] In addition, in the step (3), the calcium compound may be one or more selected from calcium oxide, calcium hydroxide, calcium sulfate, and calcium phosphate.

[0019] In addition, the present disclosure provides a filler for papermaking, wherein a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region, and a metal carbonate has a shape in which it is disposed on the fiber fibrils, the filler for papermaking comprising 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate (this filler is hereinafter referred to as hybrid flexible calcium carbonate (HFCC)).

[0020] In addition, the present disclosure provides a method for manufacturing paper, comprising the steps of: (1) mixing 1 to 60 wt % of the above-described filler for papermaking (HFCC); and 40 to 99 wt % of beaten natural pulp or recycled pulp; and (2) introducing the mixture of the step (1) into a paper machine to manufacture paper.

[0021] In addition, the present disclosure provides a method for manufacturing ultra-high-filler-content paper, in which an inorganic material is 50 wt % or more of the total weight, the method comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking (HFCC); and 1 to 40 wt % of beaten natural pulp or recycled pulp; and adding 1 to 30% of an ionic polymer for strength enhancement; and (2) introducing the mixture of the step (1) into a paper machine to manufacture the paper.

[0022] In addition, the present disclosure provides a method for manufacturing a composite, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking (HFCC); and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the composite by impregnating, spraying, or performing curtain coating with 50 to 5000 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0023] In addition, the present disclosure provides a method for manufacturing stone paper, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the stone paper by coating or impregnating with 1 to 50 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0024] In addition, the present disclosure provides a paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate. In this case, the paper may comprise 1 to 60 wt % of the filler (HFCC).

[0025] In addition, the present disclosure provides ultra-high-filler-content paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0026] In this case, the ultra-high-filler-content paper may comprise the filler (HFCC) in an amount of 50 wt % or more based on the total weight of the ultra-high-filler-content paper.

[0027] In addition, the present disclosure provides a composite formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0028] In addition, the present disclosure provides a stone paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.Fiber Fibrils

[0029] In one embodiment, the present disclosure provides a method for manufacturing a papermaking filler using chitin fibril and paper including the papermaking filler manufactured thereby, and more specifically, to a method for manufacturing a papermaking filler using chitin fibril and paper including the papermaking filler manufactured thereby and the calcium compound.

[0030] In one embodiment, the present disclosure provides a method for manufacturing a papermaking filler comprising chitin fibrils converted from calcium carbonate and calcium carbonate by injecting carbon dioxide into a mixture after manufacturing the mixture, and a method for manufacturing paper using the same. paper using the papermaking filler manufactured by the method of the present disclosure has excellent strength properties compared to ground calcium carbonate or ground calcium carbonate pre-agglomerates, which are fillers mainly used in the related art, in strength properties such as bulk, hot-cutting, and flexural rigidity. when compared to wood nanocellulose, chitin, which is marine waste rather than wood pulp, is used, and has similar strength, but has the advantage of consuming much less energy required to manufacture chitin fibrils of the present disclosure than energy required to manufacture nanocellulose.

[0031] In one embodiment, the present disclosure provides a method for preparing a papermaking filler using chitin fibrils and paper including the papermaking filler prepared thereby, and the preparation of a filler using chitin fibrils or nano chitin fibrils according to the present disclosure can be a method for preparing a very excellent filler. Specifically, the present disclosure has completed the present disclosure by preparing a mixture of nano chitin fibrils and a calcium compound, injecting carbon dioxide into the mixture and reacting the mixture with the calcium compound to prepare a filler for papermaking, and preparing paper using the same, confirming that the strength properties such as bulk, hot-cutting, and bending rigidity of the prepared paper are excellent, and the energy required to prepare chitin fibrils of the present disclosure is much less than the energy required to prepare nanocellulose, which is a filler mainly used in the related art, thereby completing the present disclosure.

[0032] In one embodiment, the present disclosure provides a manufacturing method of the filler for the paper manufacture including the following steps: (1) manufacturing a mixture of chitin fibril and a calcium compound by adding 100 to 5000 parts by weight of water and 5 to 100 parts by weight of the calcium compound with respect to 1 part by weight of chitin fibril; and (2) the step of converting to the calcium carbonate the calcium compound the carbon dioxide is injected under the temperature condition of 10~80° C. into the mixture of the calcium compound and the chitin fibril manufactured from above statement step (1), wherein in step (1), the chitin fibril fibrillates chitin by using the refiner, grinder, super mass collider, disperser (homogenizer) or the super fluidizer; or in step (1), chitin fibril is treated with at least one acid selected from acetic acid, sulfuric acid, nitric acid, phosphoric acid, lactic acid, and citric acid to have a ph of 2 to 5, and then chitin is fibrillated using a refiner, a grinder, a super mass collider, a homogenizer, or a super fluidizer.

[0033] In step (1), the chitin fibril is preferably chitin fibril obtained by fibrillating chitin using a refiner, a grinder, a super mass collider, a homogenizer, or a super fluidizer after adding 1 to 10 parts by weight of any one selected from carboxymethyl cellulose (CMC), methyl cellulose, carrageenan, codonopsislanceolata, a cationic polymer, and an anionic polymer with respect to 100 parts by weight of chitin, but is not limited thereto.

[0034] As the cationic polymer, a polymer such as a polyamidoamine-epihalohydrin polymer, apolyalkyldiallylamine-epihalohydrin polymer, polyethyleneimine, polyacrylamide, polyamine, polyvinylamine, and cationic starch may be used.

[0035] As the anionic polymer, polysaccharides, proteins, polyvinyl alcohol, polyvinyl acetate, cellulosederivatives, epoxy acrylate, polyester, polyurethane, polyester acrylate, polyether acrylate, polyolefindispersions, polyamides, vinyl copolymers, polyacrylates, and the like may be used.

[0036] Here, examples of the polysaccharide include agar, sodium alginate, and modified starch (carboxymethylated starch, hydroxyethylated starch, oxidized starch, and the like), and the cationic polymer and the anionic polymer are not limited as long as calcium carbonate can be easily attached to the chitin fibril raw material.

[0037] The chitin is preferably α-chitin or β-chitin, but is not limited thereto. The chitin fibril may have an average width of preferably 1 μm or less, more preferably 10 to 1000 nm, even more preferably 10 to 100 nm, but is not limited thereto. In the present disclosure, according to the TAPPI standard definition, when the width of chitin fibril is 100 nm or less, it is named ‘nano chitin fibril. In addition, the present disclosure relates to a papermaking filler prepared by the method for preparing the papermaking filler.

[0038] Moreover, the present disclosure comprises the step of: (1) beating the pulp so that for the freeness, 100~500 Canadian Standard Freeness (CSF) be; and

[0039] (2) mixing the filler for the paper manufacture and the pulp beaten in step (1). The present disclosure relates to a method for manufacturing paper including the same.

[0040] In step (2) of the paper preparation method, it is preferable to further administer 0.05 to 0.5 parts by weight of the cationic polyacrylamide to the filler and the pulp based on 100 parts by weight of the dry weight of the filler and the pulp, but the present disclosure is not limited thereto.

[0041] The pulp may be natural pulp or recycled pulp, and is preferably a mixture of bleached conifer pulp and bleached broadleaf pulp, but is not limited thereto.

[0042] In the paper preparation method, the filler and the pulp are preferably mixed in a weight ratio of 1 to90:99 to 10, more preferably 30 to 50:70 to 50, and most preferably 30:70 or 50:50, but are not limited thereto.

[0043] In addition, the present disclosure relates to paper manufactured by the method for manufacturing the paper.

[0044] The present disclosure relates to a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound, and a use thereof, wherein paper comprising the filler for papermaking prepared by the preparation method according to the present disclosure has a greatly improved paper bulk compared to paper using a conventional ground calcium carbonate filler, has the effect of possessing an excellent breaking length, and comes to have a characteristic of excellent smoothness. By using these characteristics, it becomes possible to make paper of excellent quality even when using a larger amount of the filler than ground calcium carbonate, and therefore, the economic feasibility is excellent, and the effects of reducing the amount of organic fibers used and reducing drying energy can be obtained.BRIEF DESCRIPTION OF DRAWINGS

[0045] FIG. 1 is a process flowchart schematically showing a process of manufacturing paper using the filler for papermaking prepared according to the present disclosure.

[0046] FIG. 2 is a comparison of the bulk (A), breaking length (B), and internal bond strength (C) of the papers prepared in Examples 4 to 9 and Comparative Examples 1 to 4 of the present disclosure.

[0047] FIG. 3A and FIG. 3B are electron micrographs showing the timing of the carbon dioxide reaction in step 3 of Example 1 of the present disclosure, wherein FIG. 3A shows an initial state of the carbon dioxide reaction, FIG. 3B shows an intermediate state of the carbon dioxide reaction, and FIG. 3C is FIG. 3A is an electron micrograph of a final form of the carbon dioxide reaction.

[0048] FIG. 4A, FIG. 4B, and FIG. 4C provide results of confirming the bulk, flexural rigidity, and hot-cutting of paper, respectively, prepared in examples and comparative examples of the present disclosure.METHODS FOR PREPARING A FILLER FOR PAPERMAKING

[0049] The present disclosure relates to a method for preparing a filler for papermaking (HFCC), comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.

[0050] In this case, the step (1) may also be performed by a method comprising: 1) preparing a separate mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100; 2) preparing by mixing an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100; or 3) mixing organic fibers and an inorganic compound and grinding to prepare a mixed aqueous solution having the same size and weight ratio.

[0051] According to an Example of the present disclosure, the step (1) may comprise: (1-1) a step of preparing a mixed solution by mixing organic fibers and an inorganic compound, and then adding water; and (1-2) a step of preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %, by grinding the mixed solution.

[0052] In this case, in the step (1-1), the organic fibers and the inorganic compound may be mixed in a weight ratio of 1:5 to 100, and the mixed solution may have a solids content of 1 to 60 wt %. In the step (1-2), the step of grinding the mixed solution of organic fibers and the inorganic compound not only reduces the size of the inorganic compound to an appropriate level, but also, as the organic fibers are fibrillated with low energy by friction with the inorganic compound in a strong alkaline state due to hydration of the inorganic compound, energy consumption in the preparation of the organic fiber fibrils can be greatly reduced compared to a method of separately preparing and using microfibrils or nanofibrils. The grinding is preferably performed using a grinder or a ball mill, but is not limited thereto.

[0053] In the steps (2) and (3), preflocs are prepared using the inorganic compound and the organic fiber fibrils that were mixed together, and by reacting in water through a method of adding calcium oxide thereon and injecting carbon dioxide, a metal carbonate is made to adhere to the surface of the preflocs, whereby a robust and elongated metal carbonate can be prepared.

[0054] In the present disclosure, preflocculation means changing the inorganic compound particles and the organic fiber fibrils into an aggregate by treating them with coagulants and a flocculant.

[0055] The stirring of the step (2) is preferably performed at 500 to 5,000 rpm; if stirring is performed at less than 500 rpm, a problem arises in that the physical properties of the paper deteriorate because the size of the aggregate particles formed is very large when paper is manufactured using them, and if stirring is performed at more than 5,000 rpm, a problem arises in that it is not effective because the particle size becomes too small.

[0056] The particle size of the preflocs formed in the step (2) may be 1 to 100 μm.

[0057] If the particle size of the preflocs formed in the step (2) is less than 1 μm, there is a problem that there is no effect of improving the physical properties of paper manufactured using them because the size of the preflocs is very small, and if it exceeds 100 μm, there is a problem that it is difficult for the filler to be uniformly distributed when manufacturing paper using them.

[0058] The inorganic compound may comprise one or more selected from calcium carbonate (CaCO3), calcium oxide (CaO), calcium hydroxide (Ca(OH) 2), magnesium carbonate (MgCO3), gypsum, kaolin, calcined clay, talc, perlite, diatomaceous earth, zinc carbonate, lithium carbonate, magnesium hydroxide, and aluminum trihydrate, and may preferably comprise a metal carbonate comprising one or more selected from calcium carbonate, magnesium carbonate, aluminum carbonate, lithium carbonate, and zinc carbonate, and more preferably may be calcium carbonate, but is not limited thereto.

[0059] The calcium carbonate is preferably one or more selected from ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC), but is not limited thereto, and the fiber fibril preferably comprises one or more selected from cellulose and chitin, but is not limited thereto.

[0060] The ionic polymer is preferably one or more ionic polymers selected from an anionic polymer and a cationic polymer, but is not limited thereto.

[0061] The anionic polymer is preferably one or more selected from a polysaccharide, a protein, polyvinyl alcohol, polyvinyl acetate, a cellulose derivative, epoxy acrylate, polyester, polyurethane, polyester acrylate, polyether acrylate, a polyolefin dispersion, polyamide, a vinyl copolymer, and polyacrylate, but is not limited thereto. The cationic polymer is preferably one or more selected from a polyamidoamine-epihalohydrin polymer, a polyalkyldiallylamine-epihalohydrin polymer, polyethyleneimine, polyacrylamide, polyamine, polyvinylamine, and a cationic starch, but is not limited thereto.

[0062] The amount of the ionic polymer added in the step (2) is preferably 0.01 to 10 parts by weight of the ionic polymer with respect to 100 parts by weight of the mixed aqueous solution, and more preferably 0.1 to 0.3 parts by weight of the ionic polymer, but is not limited thereto.

[0063] In the step (3), the calcium compound is preferably one or more calcium compounds selected from calcium oxide, calcium hydroxide, calcium sulfate, and calcium phosphate, and more preferably is calcium oxide or calcium hydroxide, but is not limited thereto.

[0064] In a case where calcium hydroxide is used as the calcium compound, calcium hydroxide prepared by reacting sodium hydroxide and calcium chloride may be used. That is, because calcium hydroxide can be formed by reacting sodium hydroxide and calcium chloride, calcium carbonate can be formed by reacting with carbon dioxide even without directly adding calcium hydroxide.

[0065] In the step (3), the calcium contained in the calcium compound component is dissolved in the form of a salt such as calcium hydroxide in the diluted solution in which the preflocs are formed, and calcium carbonate can be synthesized through a carbonation reaction by injecting carbon dioxide thereinto. In this case, it is preferable to react the carbon dioxide until the pH of the diluted solution generally reaches 7.0, and it is necessary to carry out the reaction until the injected carbon dioxide no longer reacts. In addition, in the step (3), the temperature for reacting the diluted solution by injecting carbon dioxide is preferably 10 to 80° C.

[0066] In addition, the present disclosure provides a filler for papermaking, wherein a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region, and a metal carbonate has a shape in which it is disposed on the fiber fibrils, the filler comprising 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0067] As the filler has a structure in which the metal carbonate is disposed on the fiber fibrils, when forming paper comprising the same, the bulk of the paper is greatly improved, it has an excellent breaking length, and it may be more advantageous in terms of having excellent smoothness. In addition, as the filler satisfies the content range of the fiber fibrils and the metal carbonate, when forming paper comprising the same, the bulk of the paper is greatly improved, it has an excellent breaking length, and it may be more advantageous in terms of having excellent smoothness.

[0068] In addition, the present disclosure provides a method for manufacturing paper, comprising the steps of: (1) mixing 1 to 60 wt % of the above-described filler for papermaking (HFCC); and 40 to 99 wt % of beaten natural pulp or recycled pulp; and (2) introducing the mixture of the step (1) into a paper machine to manufacture paper.

[0069] In addition, the present disclosure provides a method for manufacturing ultra-high-filler-content paper, in which an inorganic material is 50 wt % or more of the total weight, the method comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; and adding 1 to 30% of an ionic polymer for strength enhancement; and (2) manufacturing the ultra-high-filler-content paper by introducing the mixture of the step (1) into a paper machine.

[0070] In addition, the present disclosure provides a method for manufacturing a composite, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the composite by performing impregnation, spraying, and / or curtain coating with 50 to 5000 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0071] The composite is a material that exhibits new characteristics different from previous materials by combining two or more materials of different characteristics, and the difference from a synthetic material is that the constituent components are still separated and unchanged. The composite can replace metal instruments or metal sheets in airplanes or automobiles, and its uses, such as for cell phone cases, tennis rackets, golf clubs, industrial pipes or tanks, are endless, and continuous development of applications is being carried out. In the present disclosure, as a synthetic polymer or a biodegradable polymer is added to the metal carbonate, it is characterized in that high strength and dimensional stability are enhanced, and it can be used for various applications.

[0072] In addition, the present disclosure provides a method for manufacturing stone paper, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the stone paper by coating or impregnating with 1 to 50 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0073] Although the stone paper uses the name ‘paper’, it is something that can replace paper or plastic. The stone paper is robust, and although it has waterproof properties, it has a characteristic of decomposing in a short time like a biodegradable plastic after use; it can be processed into various forms and can be folded, and its printability is superior to that of ordinary paper.

[0074] Currently manufactured stone papers have a density of 1.0 or more and thus have the disadvantage of being heavy when making books or printed materials, but the stone paper using the metal carbonate manufactured in the present disclosure has a density of 1.0 or less and thus can be comparable to ordinary paper, and as it has high hydrophobicity, high-grade printability, and biodegradability, it is an inexpensive material that can replace non-degradable plastics or paper that uses wood.

[0075] In addition, the present disclosure provides a paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate. In this case, the paper may comprise 1 to 60 wt % of the filler (HFCC).

[0076] In addition, the present disclosure provides ultra-high-filler-content paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0077] In this case, the ultra-high-filler-content paper comprises the filler (HFCC) in an amount of 50 wt % or more based on the total weight of the ultra-high-filler-content paper.

[0078] In addition, the present disclosure provides a composite characterized in that the composite is formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0079] In addition, the present disclosure provides a stone paper characterized in that the stone paper is formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0080] As the paper and the ultra-high-filler-content paper use the filler (HFCC), the bulk is greatly improved, they have an excellent breaking length, and they may be more advantageous in terms of having excellent smoothness.

[0081] In addition, as the filler satisfies the weight range of the fiber fibrils and the metal carbonate, it may be more advantageous in terms of manufacturing a biocomposite and a stone paper.EXAMPLES

[0082] Hereinafter, the present disclosure will be described in more detail using Examples. It is apparent to a person having ordinary skill in the art to which the present disclosure pertains that these Examples are only for describing the present disclosure more specifically, and the scope of the present disclosure is not limited by them.Example 1. Preparation 1 of Filler for Papermaking

[0083] Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of calcium oxide (CaO. Taekyung Industrial. Diameter about 10 μm) to 200 ml of water.

[0084] The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm.

[0085] Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the calcium oxide and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium oxide was 3.1 μm, and the average width of the organic fibers was about 678 nm.

[0086] Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of calcium oxide and organic fiber fibrils after the ball mill treatment was finished, 0.1 parts by weight of a cationic polymer, polyacrylamide (PAM, Ciba Chemical Korea), was added to impart a weak cationic property, and thereafter, in a state where a vortex was formed, with respect to 100 parts by weight of total solids, 0.1 parts by weight of an anionic polymer, a micropolymer (Eka Chemical Korea), was added so that the overall zeta potential, that is, the charge, maintained neutrality. Here, the precise amount of ionic polymer added was based on the zeta potential. Thereafter, the diluted solution was stirred at a rotation speed of 2,000 rpm for 10 minutes to form preflocs.

[0087] Step 3: After the step 2, after additionally adding 5 g of calcium oxide to the mixed aqueous solution, the filler for papermaking was prepared by continuously injecting carbon dioxide into the diluted solution while stirring at 2000 rpm at 30° C. until the pH reached 7.0. Here, the reaction endpoint was also set as the point at which the injection rate and the discharge rate of carbon dioxide became equal.

[0088] In this case, a total amount of 45 g of calcium oxide reacted to form 80 g of precipitated calcium carbonate, thereby forming a filler attached to 2 g of cellulose fibrils (cellulose fibrils: precipitated calcium carbonate=1:40).Example 2. Preparation 2 of Filler for Papermaking

[0089] Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of ground calcium carbonate (GCC, Omyakorea Co., Ltd. Diameter 5 μm or more) to 200 ml of water. The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm. Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the ground calcium carbonate and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium carbonate was 3.2 μm, and the average width of the organic fibers was about 825 nm.

[0090] Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of ground calcium carbonate and organic fiber fibrils after the ball mill treatment was finished, 0.1 parts by weight of a cationic polymer, polyacrylamide (PAM, Ciba Chemical Korea), was added to impart a weak cationic property, and thereafter, in a state where a vortex was formed, with respect to 100 parts by weight of total solids, 0.1 parts by weight of an anionic polymer, a micropolymer (Eka Chemical Korea), was added so that the overall zeta potential, that is, the charge, maintained neutrality. Here, the precise amount of ionic polymer added was based on the zeta potential.

[0091] Thereafter, the diluted solution was stirred at a rotation speed of 2,000 rpm for 10 minutes to form ground calcium carbonate-cellulose fibril preflocs.

[0092] Step 3: After adding 22.5 g of calcium oxide to the preflocs formed in the step 2 under a vortex of 2,000 rpm at 30° C., the filler for papermaking was prepared by continuously injecting carbon dioxide into the diluted solution until the pH reached 7.0. Here, the reaction endpoint could also be set as the point at which the injection rate and the discharge rate of carbon dioxide became equal. In this case, 40 g of ground calcium carbonate and 40 g of newly generated precipitated calcium carbonate formed a filler (HFCC) attached to the surface of the cellulose fibrils.Example 3. Preparation 3 of Filler for Papermaking

[0093] Step 1-1: A diluted mixture was prepared by adding 5.6 g of the calcium oxide used in step 1-1 of Example 1, 30 g of the ground calcium carbonate used in step 1-1 of Example 2, and 2 g of organic fibers to 200 ml of water.

[0094] Step 1-2: Grinding was performed using a ball mill as in step 1-2 of Example 2. After grinding, the average width of the cellulose fibrils was confirmed to be 782 nm.

[0095] Step 2: Preflocs were formed in the same manner as in step 2 of Example 2.

[0096] Step 3: In the same manner as step 3 of Example 2, to make the total amount of calcium oxide 22,5 g, 16.9 g of calcium oxide, excluding the 5.6 g of calcium oxide added in the step 1-1, was additionally added so that the total amount of calcium oxide became 22.5 g, and the filler was prepared by injecting carbon dioxide into the ground calcium carbonate at 30° C. to attach it to the cellulose fibrils together with newly generated precipitated calcium carbonate. The reason for adding the calcium oxide in divided portions in this manner is to maintain an alkaline state during the ball mill treatment to aid in the fibrillation of the organic fibers.Example 4. Preparation 1 of Paper Comprising Filler for Papermaking

[0097] Step 1: As pulp for making paper, bleached softwood pulp and bleached hardwood pulp were mixed at a ratio of 2:8, and after performing beating so that the freeness became 500 ml CSF (Canadian Standard Freeness), the filler for papermaking prepared in Example 1 and the pulp were mixed at a weight ratio of 25:75.

[0098] Step 2: Using the filler for papermaking and the pulp mixed in the step 1, paper having a basis weight of 60 g / m2 was manufactured according to a paper testing method (ISO 5269 / 1) (FIG. 1).Example 5. Preparation 2 of Paper Comprising Filler for Papermaking

[0099] Paper was manufactured under the same conditions as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 1 and the pulp were mixed at a weight ratio of 35:65.Example 6. Preparation 3 of Paper Comprising Filler for Papermaking

[0100] Paper was manufactured under the same conditions as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 2 was used.Example 7. Preparation 4 of Paper Comprising Filler for Papermaking

[0101] Paper was manufactured in the same manner as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 2 and pulp were mixed at a weight ratio of 35:65.Example 8. Preparation 5 of Paper Comprising Filler for Papermaking

[0102] Paper was manufactured by performing in the same manner as in Example 4, except that the filler for papermaking used in step 1 of Example 4 was the filler for papermaking prepared in Example 3.Example 9. Preparation 6 of Paper Comprising Filler for Papermaking

[0103] Paper was manufactured in the same manner as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 3 and pulp were mixed at a weight ratio of 35:65.Comparative Example 1

[0104] Step 1: As pulp for manufacturing paper, bleached softwood pulp and bleached hardwood pulp were mixed at a ratio of 2:8, and beating was performed so that the freeness became 500 ml CSF (Canadian Standard Freeness).

[0105] Step 2: Ground calcium carbonate (GCC, Omyakorea Co., Ltd. 2 to 3 μm) as a filler and the pulp beaten in the step 1 were mixed at a weight ratio of 25:75, and paper having a basis weight of 60 g / m2 was manufactured according to a paper testing method (ISO 5269 / 1).Comparative Example 2

[0106] Paper was manufactured under the same conditions as in the Comparative Example 1, with the exception that in step 2 of the Comparative Example 1, the filler and the pulp were mixed at a weight ratio of 35:65.Comparative Example 3

[0107] Paper was manufactured under the same conditions as in the Comparative Example 1, with the exception that in step 2 of the Comparative Example 1, precipitated calcium carbonate (PCC, manufactured by Artone Paper. About 1.5 μm) was used instead of ground calcium carbonate.Comparative Example 4

[0108] Paper was manufactured under the same conditions as in the Comparative Example 1, with the exceptions that in step 2 of the Comparative Example 1, precipitated calcium carbonate (PCC, manufactured by Artone Paper. About 1.5 μm) was used instead of ground calcium carbonate, and the filler and the pulp were mixed at a weight ratio of 35:65.

[0109] The GCC filler used in the Comparative Examples 1 and 2 was a filler mainly used in a general wood-free paper factory, and the PCC filler used in the Comparative Examples 3 and 4 is a high-grade filler used to increase bulk and brightness more than GCC.Experimental Example 1. Analysis of Paper Characteristics

[0110] To analyze the characteristics of the paper manufactured comprising the filler for papermaking according to the present disclosure, the following experiments were conducted.(1) Analysis of Bulk and Breaking Length of Paper

[0111] To evaluate the effectiveness of the papers prepared in Examples and Comparative Examples according to the present disclosure, the bulk and breaking length of the prepared papers were analyzed. The basis weight of the paper prepared in Examples 4-9 and Comparative Examples 1 to 4 was 60 g / m2. In addition, the bulk and breaking length were analyzed. The bulk was obtained by measuring the density of the paper (unit g / cm3) and then taking the reciprocal (bulk unit cm3 / g). The breaking length (unit km) is a value obtained by dividing the tensile strength (unit kN / m) by the basis weight of the paper, and as a value that eliminates the influence of the deviation of the basis weight in the comparison of tensile strength, it can be said to be a more reliable value in the comparison of strength.

[0112] As a result, as shown in Table 1 below, the bulk of the paper prepared with GCC (ground calcium carbonate) in Comparative Example 1 and Comparative Example 2 was 1.71 and 1.68, respectively, which was much lower than the bulk of the paper prepared in Examples 4 to 9, which was 1.86 to 1.92, and this leads to a very large difference in thickness and bending stiffness, which are important physical properties of actual paper. In particular, since bending stiffness is proportional to the third power of the paper thickness, a very large difference in bending stiffness occurs (Table 1).

[0113] Since the bending stiffness decreases when the filler content is increased, this is an important reason why the filler content cannot be increased, but it was confirmed that the filler according to the present disclosure exhibits a very high bending stiffness (bending stiffness of Examples 4 to 9 was 550 to 680; bending stiffness of Comparative Examples 1 and 2 was 150 to 250).

[0114] The bulk of the paper prepared using PCC (precipitated calcium carbonate) in Comparative Examples 3 and 4 was 1.84 and 1.83, respectively, which can exhibit a higher bulk than ground calcium carbonate, and it can be seen that it exhibits a bulk value similar to the bulk of Examples 4 to 9.

[0115] However, it can be confirmed that precipitated calcium carbonate (PCC) has a very low tensile strength compared to Examples 4 to 9 (Table 1 and FIG. 2).

[0116] In addition, as shown in Table 1 below, the breaking length of the paper manufactured using ground calcium carbonate (GCC) in Comparative Example 1 and Comparative Example 2 was shown to be 2.18 when 25% of filler was added, and 1.84 when 35% was added. The breaking length of the paper manufactured in Examples 4 to 9 was shown to be 3.13 to 3.53 when 25% of filler was added, and 3.07 to 3.14 when 35% of filler was added, and thus, compared to Comparative Examples 1 to 2, it was confirmed that the breaking length of Examples 4 to 9 of the present disclosure was significantly higher under the same filler content.

[0117] In the case of the breaking length of paper manufactured using precipitated calcium carbonate (PCC), it was 1.88 when 25% of filler was added and 1.65 when 35% was added, which was lower under the same filler content than in the case of Examples 4 to 9 or even in the case of Comparative Example 1 and Comparative Example 2 using ground calcium carbonate (GCC). Accordingly, it could be confirmed that the paper manufactured using the filler for papermaking according to the present disclosure has high bulk and breaking length. FIG. 2 compared the bulk, breaking length, and internal bond strength when 25% and 35% of filler were added. It was confirmed that the bulk, breaking length, and internal bond strength of Examples 4 to 9 were all higher than in the case of using ground calcium carbonate or precipitated calcium carbonate as a filler.(2) Analysis of Brightness and Smoothness of Paper

[0118] To evaluate the effectiveness of the papers prepared in Examples and Comparative Examples according to the present disclosure, the brightness and smoothness of the prepared papers were analyzed. Specifically, the brightness analysis was measured using the ISO 2470 method, which is a method for measuring paper brightness, and the smoothness was measured using the Bekk smoothness method TAPPI T479 cm-99.

[0119] As a result, as disclosed in Table 1 below, Comparative Example 1 and Comparative Example 2 used ground calcium carbonate, and the brightness showed an average of 86.3%. Comparative Example 3 and Comparative Example 4 used precipitated calcium carbonate, and showed an average brightness of 88.8%. That is, precipitated calcium carbonate showed a significantly higher brightness than ground calcium carbonate. The average brightness of Examples 4 and 5 was 88.5%, which was higher than in the case of ground calcium carbonate and was at a level similar to that of precipitated calcium carbonate. However, the average brightness of Examples 6 and 7 was 87.3%, which was lower than in the case of using only precipitated calcium carbonate. The average brightness of Examples 8 and 9 was 88.8%, which was at a level similar to the brightness of precipitated calcium carbonate, and it was judged that this result was due to the effect of precipitated calcium carbonate being mainly synthesized and attached to the filler surface of Examples 8 and 9. It was judged that the case of Examples 6 and 7 was due to a significant amount of ground calcium carbonate being included.

[0120] It could be seen that the paper comprising HFCC, which is the filler for papermaking according to the present disclosure, has superior bulk, breaking length, and bending stiffness than in the case of ground calcium carbonate or precipitated calcium carbonate, and has a characteristic in that brightness and smoothness are maintained.TABLE 1Results of Paper Characteristic AnalysisInternalBondBendingFiller:PulpBreakingTensileStrengthStiffnessType ofType ofMixingBrightnessBulkLengthStrengthSmoothness*(lbfft / (GurleyPaperFillerRatio(%)(cc / g)(km)(kN / m)(sec)in2 × 1000)unit)Example 4Example 125:7588.81.893.452.0312.375.8652.4Example 5Example 135:6588.11.913.131.8413.871.5565.3Example 6Example 225:7587.41.863.131.8515.777.2621.5Example 7Example 235:6587.21.863.071.8115.574.3548.6Example 8Example 325:7588.81.883.532.0814.874.3635.8Example 9Example 335:6588.91.893.141.8513.272.1568.2ComparativeGCC25:7586.21.712.181.2813.468.5245.6Example 1ComparativeGCC35:6586.31.681.841.0812.765.2168.2Example 2ComparativePCC25:7588.61.841.881.1114.566.3235.6Example 3ComparativePCC35:6589.11.831.650.9515.862.5142.8Example 4(3) Evaluation of Shape and Composition of Filler

[0121] With respect to the filler for papermaking prepared in Examples 1 to 3, by observing through an electron microscope during the intermediate process of filler formation, the process of calcium carbonate attaching and forming on the central region of a plurality of fiber fibrils could be confirmed, and this is shown in FIG. 3. As seen in FIG. 3, when calcium carbonate is formed on the fiber fibrils, it can be seen that a plurality of fiber fibrils is involved, and when sufficient calcium carbonate is attached, the appearance of the fiber fibrils is no longer visible. As a result, it was confirmed that the filler for papermaking prepared in Examples 1 to 3 has a plurality of fiber fibrils present in a central region, and has a shape in which calcium carbonate is attached to the fiber fibrils.

[0122] Also, the fiber fibril and metal carbonate content were measured using the standard method TAPPI T211 om-02 (Ash in wood, pulp and paperboard: combustion at 525° C.). That is, from a filler sample using the prepared calcium carbonate metal salt, moisture was removed at 105° C., and after measuring the total weight (A), it was treated again at 525° C. for 1 hour and then cooled to measure its weight (B). At this time, the calcium carbonate remains as it is, but all of the fiber fibrils are removed as water and carbon dioxide. The value (A-B) is the weight of the fiber fibrils, and B becomes the weight of the calcium carbonate.

[0123] In addition, the content of fiber fibrils and metal carbonate within the filler prepared in Examples 1 to 3 was measured, and the results are shown in Table 2 below. The specific gravity of calcite-form calcium carbonate is 2.7, and the specific gravity of cellulose is known to be 1.5.

[0124] Therefore, if the weights of the calcium carbonate and the fiber fibrils are known, their volume can be calculated.TABLE 2FiberCalciumFiberCalciumFibrilCarbonateFibrilCarbonateItem(wt %)(wt %)(vol %)(vol %)Example 13.296.85.694.4Example 24.295.87.392.7Example 33.896.26.693.4

[0125] As can be seen in Table 2 above, it could be seen that Examples 1 to 3 according to the present disclosure satisfy the content range of fiber fibrils and metal carbonate according to the present disclosure, and accordingly, it can be seen that effects of improved bulk and excellent breaking length and smoothness, as in Table 1 above, can all be expressed simultaneously.<Preparation of Ultra-High-Filler-Content Paper>

[0126] Step 1: As pulp for making ultra-high-filler-content paper, bleached softwood pulp and bleached hardwood pulp were mixed at a ratio of 5:5, and after performing beating so that the freeness became 300 ml CSF (Canadian Standard Freeness), the filler for papermaking prepared in Example 1 and pulp were mixed at a weight ratio of 60:40, and this was referred to as ‘ultra-high-filler-content paper 1’ stock. Also, the filler for papermaking and pulp were mixed at a weight ratio of 70:30, and this was referred to as ‘ultra-high-filler-content paper 2’ stock.

[0127] Step 2: To each of the ‘ultra-high-filler-content paper 1’ stock and ‘ultra-high-filler-content paper 2’ stock mixed in the step 1, 5 wt % of epoxy resin relative to the solids content was added, and paper having a basis weight of 60 g / m2 was manufactured according to a paper testing method (ISO 5269 / 1). The physical properties of the manufactured ultra-high-filler-content paper are shown in Table 3 in comparison with the physical properties of Comparative Example 2. The content of the filler included in the paper was calculated by comparing the remaining solids with the initial paper weight after reacting the paper at 525° C. for 1 hour, and is shown as ash content in Table 3. The bulk, breaking length, and smoothness of the ultra-high-filler-content paper to which 50% or more of filler was added were significantly superior to those of Comparative Example 2. Therefore, it was confirmed that the filler prepared in Example 1 can be used for the preparation and use of ultra-high-filler-content paper.TABLE 3Comparison of Physical Properties of Ultra-High-Filler-Content PaperFiller:PulpAshBreakingTensileType ofType ofMixingContentBrightnessBulkLengthStrengthSmoothness*PaperFillerRatio(wt %)(%)(cc / g)(km)(kN / m)(sec)Ultra-high-Example60:4057.588.81.982.451.4342.3filler-content1paper 1Ultra-high-Example70:3066.789.12.102.131.2544.8filler-content1paper 2ComparativeGCC35:6533.286.31.681.841.0812.7Example 2Preparation Example 2: Preparation of Composite

[0128] Step 1: To prepare a sheet for making a biocomposite, after performing beating on bleached softwood pulp so that the freeness became 300 ml CSF (Canadian Standard Freeness), it was mixed with the filler for papermaking prepared in Example 1 at a weight ratio of 10:90 (beaten bleached softwood pulp: filler of Example 1), and to this stock, 8 wt % of epoxy resin relative to the solids content was added to prepare a paper specimen having a basis weight of 80 g / m2 according to a paper testing method (ISO 5269 / 1).

[0129] Step 2: After melting PLA at 220 to 240° C., curtain coating was performed at 350 g / m2 on the paper prepared in step 1 to prepare a ‘biocomposite’. For comparison, a sheet was prepared with only PLA at 430 g / m2 without a paper specimen, and was referred to as ‘biocomposite PLA’.

[0130] The temperature of the nozzle was maintained at 240° C. In the case of the paper specimen, coating was performed with the temperature raised to 100° C., a vacuum plate was applied to the side opposite to where the coating was performed, and a vacuum of 0.6 atm was maintained to adjust for effective internal penetration of the PLA.

[0131] Step 3: The biocomposite was completed after smoothing the surface of the paper specimen, into which the PLA had sufficiently penetrated, using a roller.

[0132] The weight and density of the prepared biocomposite were measured at room temperature, the PLA content was calculated, and the content of calcium carbonate was measured by measuring the weight after treating at 525° C. for 3 hours. In addition, the tensile strength was measured and is shown in Table 4.TABLE 4Physical Properties of BiocompositeAshBasisTensileElonga-PLAType ofType ofContentWeightStrengthtionContentPaperFiller(wt %)(g / m2)(MPa)(%)(wt %)BiocompositeExam-17.2433.334.72.381.5ple 1Biocomposite00.1430.00.00.0100.0PLA

[0133] In Table 4, because the Biocomposite PLA was very brittle, it was impossible to measure the tensile strength. On the other hand, the Biocomposite recorded an elongation, which is the strain at the point of fracture by tensile force, of 2.3%. As the Biocomposite PLA recorded an elongation of 0.0, it did not exhibit any tensile stress at all. The tensile strength of the Biocomposite was recorded as 34.7 MPa, and thus it was not significantly different from a general PLA composite.Preparation Example 3: Preparation of Stone Paper

[0134] Step 1: To prepare a sheet for making stone paper, after performing beating on bleached softwood pulp so that the freeness became 300 ml CSF (Canadian Standard Freeness), it was mixed with the filler for papermaking prepared in Example 1 at a weight ratio of 10:90 (beaten bleached softwood pulp: filler of Example 1), and to this stock, 8 wt % of epoxy resin relative to the solids content was added to prepare a paper specimen having a basis weight of 80 g / m2 according to a paper testing method (ISO 5269 / 1).

[0135] Step 2: After melting HDPE having a density of 0.935 g / cm3 at 200 to 220° C., curtain coating was performed in an amount of 20 g / m2 on the paper prepared in step 1. At this time, with the temperature of the paper specimen raised to 100° C., a vacuum plate of 0.6 atm was applied to the side opposite to the surface where the coating was performed to adjust for effective internal penetration of the HDPE.

[0136] Step 3: The ‘stone paper’ was completed after smoothing the surface of the paper specimen, into which the HDPE had sufficiently penetrated, using a roller.

[0137] The weight and density of the prepared stone paper were measured at room temperature, the HDPE content was calculated, and the content of calcium carbonate was measured by measuring the weight after treating at 525° C. for 1 hour. In addition, the tensile strength was measured and is shown in Table 5.TABLE 5Comparison of Physical Properties of Stone PaperAshBasisTensileHDPEType ofType ofContentWeightDensityStrengthContentPaperFiller(wt %)(g / m2)(cc / g)(kN / m)(wt %)Stone PaperExample73.2101.30.8852.4618.51ComparativeGCC33.260.20.5951.080.0Example 2Preparation Example 1. Preparation of Chitin Fibril Raw Material

[0138] Beta-Chitin was added to a super mass colloider and passed through the super mass colloider three times repeatedly to prepare chitin fibrils, and it was confirmed with an electron microscope that the prepared chitin fibrils had an average width of 1 μm or less.Preparation Example 2. Preparation of Nanokitin Fibril Raw Material

[0139] Beta-chitin was added to a super mass colloider and passed through the super masscolloider nine times repeatedly to prepare nano chitin fibrils, and it was confirmed by electron microscopy that the average width of the prepared nanochitin fibrils was 100 nm or less. The fibrillation energy required to prepare β-chitin into nanochitin fibrils was measured at 3 mwh / ton.Preparation Example 3. Preparation of Acid-Treated Chitin Fibril Raw Material

[0140] After β-chitin was treated with acetic acid at pH 3 for 24 hours, it was put into a super mass colloider and passed once to prepare chitin fibrils, and it was confirmed by electron microscopy that the average width of the prepared fibrils was 1 μm or less.Manufacturing Example 4. Preparation of Acid-Treated Nanochitin Fibril Raw Material

[0141] After β-chitin was treated with acetic acid at pH 3 for 24 hours, it was put into a super mass colloiderand passed twice repeatedly to prepare nanochitin fibrils, and it was confirmed with an electron microscope that the prepared fibrils had an average width of 100 nm or less.Example 11. Preparation of Papermaking Filler 11(1) Based on 1 part by weight of chitin fibril prepared in preparation example 11, 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to prepare a mixture.

[0143] (2) while stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare filler 11 for papermaking having a weight ratio of chitin fibril:calcium carbonate of 1:80.Example 12. Preparation of Papermaking Filler 12(1) 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to 1 part by weight of the nanochitin fibril prepared in preparation example 12 to prepare a mixture.

[0145] (2) while stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxidewas converted into calcium carbonate (CaCO3) to prepare filler 12 for papermaking having a weight ratioof nanochitin fibril: calcium carbonate of 1:80.Example 13. Preparation of Papermaking Filler 13(1) Based on 1 part by weight of chitin fibril prepared in preparation example 3, 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to prepare a mixture.

[0147] (2) While stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare filler 13 for papermaking having a weight ratio of chitin fibril:calcium carbonate of 1:80.Example 14. Preparation of Papermaking Filler 14(1) 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to 1 part by weight of the nanochitin fibril prepared in preparation example 4 to prepare a mixture.

[0149] (2) While stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare filler 14 for papermaking having a weight ratio of nanochitin fibril:calcium carbonate of 1:80.Example 15. Preparation of Paper Comprising Pulp and Filler 11 for Paper Making Mixed at a Weight Ratio of 30:70(1) Bleached coniferous pulp and bleached broadleaf pulp for paper preparation were mixed at a weight ratio of 2:8 to prepare a beaten pulp having a freeness of 500 Canadian Standard Freeness (CSF).

[0151] (2) The papermaking filler 1 prepared in example 11 and the pulp beaten in step (1) were mixed at a weight ratio of 30:70.

[0152] (3) Paper was prepared according to a paper test method (ISO 5269 / 1) using a papermaking filler and pulp mixed at a weight ratio of 30:70 after step (2).

[0153] At this time, in order to improve the retention rate of the filler as a whole, 0.1 parts by weight of cationic polyacrylamide (PAM, Korean Ciba Chemical Co., Ltd.) was administered as a retention agent based on 100 parts by weight of the dry weight of the furnish (filler and pulp).Example 16. Preparation of Paper Comprising Pulp and Filler 11 for Papermaking Mixed at a Weight Ratio of 50:50

[0154] Paper was prepared in the same manner as in example 15, except that the papermaking filler 11 prepared in example 11 and the pulp were mixed in a weight ratio of 50:50 in step (2) of example 15.Example 17. Preparation of Paper Comprising Pulp and Filler 12 for Papermaking Mixed at a Weight Ratio of 30:70

[0155] Paper was prepared in the same manner as in example 15, except that the papermaking filler 12 and the pulp prepared in example 12 were mixed in a weight ratio of 30:70 in step (2) of example 5.Example 18. Preparation of Paper Comprising Pulp and Filler 12 for Papermaking Mixed at a Weight Ratio of 50:50

[0156] Paper was prepared in the same manner as in example 15, except that in step (2) of example 15, the papermaking filler 12 and the pulp prepared in example 12 were mixed at a weight ratio of 50:50.Example 19. Preparation of Paper Comprising Pulp and Filler 13 for Paper Making Mixed at a Weight Ratio of 30:70

[0157] Paper was prepared in the same manner as in example 15, except that the papermaking filler 13 and the pulp prepared in example 13 were mixed in a weight ratio of 30:70 in step (2) of example 15.Example 20. Preparation of Paper Comprising Pulp and Filler 13 for Papermaking Mixed at a Weight Ratio of 50:50

[0158] Paper was prepared in the same manner as in example 15, except that the papermaking filler 13 and the pulp prepared in example 13 were mixed in a weight ratio of 50:50 in step (2) of example 15.Example 21. Preparation of Paper Comprising Pulp and Filler 14 for Papermaking Mixed at a Weight Ratio of 30:70

[0159] Paper was prepared in the same manner as in example 15, except that the papermaking filler 14 and the pulp prepared in example 14 were mixed in a weight ratio of 30:70 in step (2) of example 15.Example 22. Preparation of Paper Comprising Pulp and Filler 14 for Papermaking Mixed at a Weight Ratio of 50:50

[0160] Paper was prepared in the same manner as in example 115, except that the papermaking filler 4 and the pulp prepared in example 14 were mixed in a weight ratio of 50:50 in step (2) of example 15.Comparative Example 11. Manufacture of Paper Using Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 30:70(1) As a pulp for making paper, bleached conifer pulp and bleached broadleaf pulp were mixed at a weight ratio of 2:8 to prepare pulp beaten to have a freeness of 500 CSF.

[0162] (2) Grond calcium carbonate (GCC) having an average particle diameter of 2 μm and the pulp beaten instep (1) were mixed at a weight ratio of 30:70.

[0163] (3) After step (2), paper was prepared according to the paper test method (iso 5269 / 1) using guround calcium carbonate (GCC) and pulp mixed at a weight ratio of 30:70.

[0164] At this time, in order to improve the retention rate of the filler as a whole, cationic polyacrylamide (PAM, Ciba Chemical Korea) as a retention agent was administered in an amount of 0.1% based on the dry weight of the furnish.Comparative Example 12. Manufacture of Paper Using Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 50:50

[0165] Paper was prepared in the same manner as in comparative example 11, except that ground calcium carbonate (GCC) having an average particle diameter of 2 μm and pulp were mixed in a weight ratio of 50:50 in step (2) of comparative example 11.Comparative Example 13. Preparation of Ground Calcium Carbonate Preaggregates(1) A dilution was prepared by mixing 50 g of ground calcium carbonate (GCC) and 500 ml of water.

[0167] (2) Polyacrylamide (PAM, Ciba Chemical, Korea), which is a cationic polymer, was added to the diluent prepared in step (1) to provide an overall zeta potential, that is, a cationic property having a weak charge, and while forming a vortex, a micro polymer (aka chemical, korea), which is an anionic polymer, was added to maintain the overall zeta potential, that is, a neutral charge. Here, the exact amount of the ionic polymer added was based on the zeta potential.

[0168] (3) After step (2), the diluted solution prepared in step (1) was stirred at a rotation speed of 2,000 rpm for 10 minutes to prepare a 35-40 μm ground calcium carbonate pre-aggregate.Comparative Example 14. Manufacture of Paper Using Pre-Aggregate of Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 30:70(1) As pulp for making paper, bleached conifer pulp and bleached broadleaf pulp were mixed at a ratio of 2:8 to prepare pulp beaten to have a freeness of 500 CSF.

[0170] (2) The ground calcium carbonate (GCC) preaggregate prepared in comparative example 3 and pulp were mixed at a weight ratio of 30:70.

[0171] (3) After step (2), paper was prepared according to the paper test method (iso 5269 / 1) using the GCC pre-aggregate and pulp mixed in step 1.

[0172] At this time, in order to improve the retention rate of the filler as a whole, 0.1% of cationic polyacrylamide (PAM, Ciba Chemical Korea) was administered as a retention agent based on the dry weight of the furnish.Comparative Example 15. Manufacture of Paper Using Pre-Aggregate of Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 50:50

[0173] In step (2) of comparative example 14, a paper was prepared in the same manner as in comparative example 14, except that the ground calcium carbonate (GCC) preaggregate prepared in comparative example 13 and the pulp were mixed at a weight ratio of 50:50.Comparative Example 16. Preparation of Nanocellulose Filler for Papermaking Having Weight Ratio of Wood Nanocellulose:Calcium Carbonate of 1:40(1) In order to prepare wood nanocellulose, bleached broad-leaved pulp was beaten so that the freeness was 100 CSF (at this time, the beating energy was 185 kwh / ton), and this was put back into a super mass colloider and repeatedly passed through the super mass colloider 30 times to prepare nanocellulose having an average width of fibrils of 100 nm or less. At this time, it was confirmed that the required fibrillation energy was 17 mwh / ton, and the average width of fibrillation was confirmed by electron microscopy.

[0175] (2) 1000 parts by weight of water and 22.5 parts by weight of calcium oxide were added to 1 part by weight of the nanocellulose prepared in step (1) to prepare a mixture of nanocellulose and calcium oxide.

[0176] (3) While stirring the mixture of nanocellulose and calcium oxide at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare a nanocellulose filler for papermaking having a weight ratio of nanocellulose:calcium carbonate of 1:40.Comparative Example 17. Manufacture of Paper Using Nanocellulose Filler and Pulp Mixed in Weight Ratio of 30:70(1) As pulp for making paper, bleached conifer pulp and bleached broadleaf pulp were mixed at a ratio of 2:8 to prepare pulp beaten to have a freeness of 500 CSF.

[0178] (2) the nanocellulose filler prepared in comparative example 16 and the pulp were mixed at a weight ratio of 30:70.

[0179] (3) After step (2), paper was prepared according to the paper test method (iso 5269 / 1) using the nanocellulose filler and pulp mixed in step (1). At this time, in order to improve the retention rate of the filler as a whole, 0.1% of cationic polyacrylamide (pam, ciba chemical korea) was administered as a retention agent based on the dry weight of the furnish.Comparative Example 18. Manufacture of Paper Using Nanocellulose and Pulp Mixed in Weight Ratio of 50:50

[0180] In step (1) of comparative example 17, a paper was prepared in the same manner as in comparative example 17, except that the nanocellulose filler prepared in comparative example 6 and the pulp were mixed at a weight ratio of 50:50.Experimental Example 1. Characteristic Analysis of Paper

[0181] In order to analyze the properties of paper prepared by including the papermaking filler according to the present disclosure, the following experiments were performed.(1) Bulk Analysis of Paper

[0182] In order to evaluate the effectiveness of the papers prepared in examples 5 to 12 and comparative examples 11, 12, 14, 15, 17 and 18 according to the present disclosure, the bulk of the prepared papers was analyzed. In the present disclosure, bulk refers to the volume per unit mass obtained by dividing the thickness by the basis weight.

[0183] As a result, as shown in Table 6 and FIG. 4, comparative example 11, which is a paper using general ground calcium carbonate as a filler and manufactured in a weight ratio of 30:70, exhibited a bulk of 1.51 cm3 / g, and comparative example 2, which is a paper using general ground calcium carbonate as a filler and manufactured in a weight ratio of 50:50, exhibited a bulk of 1.34 cm3 / g.

[0184] In addition, comparative example 14, which is paper in which the ground calcium carbonate pre-aggregate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 30:70, exhibited a bulk of 1.48 cm3 / g, and comparative example 15, which is paper in which the ground calcium carbonate pre-aggregate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 50:50, exhibited a bulk of 1.28 cm3 / g.

[0185] Meanwhile, comparative example 17, which is a paper prepared by using the filler of comparative example 16 in which the filler and the pulp were prepared at a weight ratio of 30:70 using the filler of comparative example 16 suggesting a method of preparing the filler by using the in-situ carbonation method on the nanocellulose of the wood pulp, exhibited a bulk of 1.72 cm3 / g, and comparative example 18, which is a paper prepared by using the filler and the pulp at a weight ratio of 50:50, exhibited a bulk of 1.74 cm3 / g. From these results, it was confirmed that paper using wood nanocellulose as a filler showed high bulk.

[0186] In the case of examples 15 and 17 in which the papermaking filler comprising chitin fibrils and nanochitin fibrils according to the present disclosure prepared in examples 11 and 12 and the pulp were paper prepared at a weight ratio of 30:70, the bulk was 1.70 and 1.72 cm3 / g, respectively, and in the case of examples 16 and 18 in which the papermaking filler comprising chitin fibrils and nanochitin fibrils according to the present disclosure prepared in examples 11 and 12 and the pulp were paper prepared at a weight ratio of 50:50, the bulk was 1.75 and 1.76 cm3 / g, respectively.

[0187] The papermaking filler comprising chitin fibrils and nanochitin fibrils prepared by the acetic acid pretreatment according to the present disclosure prepared in examples 13 and 14 and the pulp of example 9 and example 11, which are paper prepared at a weight ratio of 30:70, showed bulks of 1.72 and 1.72 cm3 / g, respectively. In the case of examples 20 and 21, in which the papermaking filler comprising chitin fibrils and nanochiitin fibrils according to the present disclosure prepared in examples 3 and 4 and the pulp were paper prepared in a weight ratio of 50:50, the bulk was 1.78 and 1.79 cm3 / g, respectively.

[0188] As described above, it was confirmed that the paper using the filler made of chitin fibrils or nanochitin fibrils according to the present disclosure not only had a high bulk as the filler made of nanocellulose, but also had a higher bulk even though the content of the filler was increased from 30% to 50%.

[0189] On the other hand, when ground calcium carbonate or ground calcium carbonate preagglomerates were included, the bulk tended to decrease significantly, unlike chitin fibrils, as the content of the filler increased.(2) Comparison of Manufacturing Energy of Nanocellulose and Nanochitin Fibril

[0190] In the process of preparing the wood nanocellulose in comparative example 6, the energy (185 kwh / ton) of beating the bleached broad-leaved pulp so that the freeness reached 100 CSF and the energy of turning the super mass colloider 30 times were 17 mwh / ton. in preparation example 2 for preparing the nanochitin fibrils of the present disclosure in contrast, the beating energy was not required, and the energy required to prepare the nanochitin fibrils was confirmed to be 3 mwh / ton by turning the super mass colloider 9 times. The difference in energy required to prepare nanocellulose and nanochitin fibrils was 5 times or more, and the nanocellulose additionally required more energy to be at the bleached broadleaf pulp to 100 CSF (Table 7). Therefore, the manufacturing cost of the nanocellulose is greatly increased, and the price of the filler manufactured by the in-situ carbonation method of the nanocellulose is inevitably significantly increased. Furthermore, wood nanocellulose is inevitably seen as more eco-friendly in that it cuts and uses wood, while chitin uses marine waste(3) Hot-Cutting Analysis of Paper

[0191] In order to evaluate the effectiveness of the papers prepared in the examples according to the present disclosure and the comparative examples, the hot-cutting of the prepared papers was analyzed, and the results are shown in Table 6 and FIG. 4.

[0192] The hot-cutting is a kind of display method indicating the tensile strength of paper, the hot-cutting refers to the length of paper at the time of breaking when the end of a test piece obtained by cutting paper to a specified size is fixed and the load is gradually increased to one end and pulled, and was measured according to iso 1924-2 test standard.

[0193] As a result, as shown in Table 6, in the case of comparative example 11, which is a paper using general ground calcium carbonate as a filler and manufactured at a weight ratio of 30:70 of the filler and pulp, a hot-cutting length of 2.89 km was shown, and in the case of comparative example 12, which is a paper using general ground calcium carbonate as a filler and manufactured at a weight ratio of 50:50 of the filler and pulp, a hot-cutting length of 1.22 km was shown.

[0194] In addition, comparative example 14, which is a paper in which the ground calcium carbonate pre-agglomerate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 30:70, exhibited a hot-cutting length of 3.02 km, and comparative example 15, which is a paper in which the ground calcium carbonate pre-agglomerate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 50:50, exhibited a hot-cutting length of 1.38 km.

[0195] On the other hand, in the case of comparative example 17, which is a paper in which the filler and the pulp were prepared at a weight ratio of 30:70 using the filler of comparative example 6 which suggested a method of preparing the filler by using an in-situ carbonation method on the nanocellulose of the wood pulp, the hot-cutting length was 3.35 km, and in the case of comparative example 18, which is a paper in which the filler and the pulp were prepared at a weight ratio of 50:50, the hot-cutting length was 1.64 km. That is, it was confirmed that the filler using wood nanocellulose also showed high hot-cutting on paper.

[0196] Meanwhile, in the case of examples 15 and 17 in which the papermaking filler including chitin fibrils and nanochitin fibrils according to the present disclosure prepared in examples 11 and 12 and the pulp were manufactured at a weight ratio of 30:70, respectively, hot-molding was 3.18 and 3.38 km, and in the case of examples 16 and 18 in which the papermaking filler including chitin fibrils and nanochitin fibrilsand the pulp were manufactured at a weight ratio of 50:50 according to the present disclosure prepared in examples 11 and 12, respectively, hot-molding was 1.60 and 1.86 km.

[0197] In addition, the papermaking filler including chitin fibrils and nanochitin fibrils prepared by the acetic acid pretreatment according to the present disclosure prepared in examples 13 and 14 and the pulp of example 19 and example 11, which are paper prepared at a weight ratio of 30:70, showed hot-cutting lengths of 3.01 and 3.15 km, respectively. In the case of example 10 and example 12, in which the papermaking filler comprising chitin fibrils and nanochitin fibrils according to the present disclosure prepared in example 13 and example 14 and the pulp were prepared in a weight ratio of 50:50, respectively, hot-molding was 1.35 and 1.55 km.

[0198] It was confirmed that the paper in which the filler made of chitin fibrils or nanochitin fibrils according to the present disclosure was used as a filler for papermaking had excellent hot-cutting like the filler made of nanocellulose. In particular, it can be seen that example 17 and example 18, in which nanochitin fibrils were prepared and used without chemical treatment, showed the highest hot-cutting length under the same calcium carbonate. In general, it is common for the hot-cutting length to decrease as the bulk increases, but it is difficult to see a case in which the bulk has a high hot-cutting length at the same time, such as a case in which chitin fibrils and nanochitin fibrils are used and a case in which nanocellulose is used. These characteristics can be said to be the characteristics of fillers using chitin fibrils and nanochitin fibrils.(4) Flexural Rigidity Analysis of Paper

[0199] Flexural rigidity is an essential property for white paper, but in order to increase flexural rigidity, there was no clear method other than increasing the basis weight of paper. The flexural stiffness of the paper is usually proportional to the three squares of the bulk of the paper and the first square of the hot-cutting. The paper prepared with the papermaking filler including chitin fibrils and nanochitin fibrils suggested in the present disclosure is expected to have a much larger bulk and a large hot-cutting length compared to the paper prepared with ground calcium carbonate, and thus the flexural rigidity is expected to be significantly increased, and there are significant differences in Table 6. As a paper containing 30% of a filler using chitin fibril, example 5, example 17, example 19, and example 11 showed a flexural rigidity of 50% or more compared to comparative example 11 in which heavy calcium carbonate was used or comparative example 14 in which a pre-aggregate of ground calcium carbonate was used, and particularly, when 50% of calcium carbonate was included, an increase in flexural rigidity showed an increase of 30% to 50% or more. Even when a filler containing nanocellulose was used, high flexural rigidity was shown as in the case of using chitin fibril. Table 6.TABLE 7Result of confirming the bulk, hot-cutting, and flexural rigidity of the paperprepared in the examples and comparative examples of the present disclosureBreakingFlexuralCalciumType ofBulkLengthRigidityCarbonatefillerFiller:Pulp(cm3 / g)(km)(Gurley unit)(%)Example 5Example 1130:701.703.18625.729.8Example 6Example 1150:501.751.60352.249.8Example 7Example 1230:701.723.38647.931.1Example 8Example 1250:501.761.86403.849.9Example 9Example 1330:701.723.01615.930.5Example 10Example 1350:501.781.35405.249.2Example 11Example 1430:701.723.15653.229.5Example 12Example 1450:501.791.55398.250.8ComparativeGCC30:701.502.89425.730.8Example 11ComparativeGCC50:501.341.22219.450.1Example 12ComparativeComparative30:701.483.02418.231.5Example 14Example 3ComparativeComparative50:501.281.38208.050.4Example 15Example 3ComparativeComparative30:701.723.35632.130.5Example 17Example 6ComparativeComparative50:501.741.64389.249.8Example 18Example 6TABLE 7Comparison of energy for manufacturingof nanochitin fibrils and nanocellulosevalley beatingsuper mass colloider fibrillatedenergy (kwh / ton)energy (mwh / ton)Nanochitin Fibril03Nanocellulose18517

Examples

example 1

Preparation 1 of Filler for Papermaking

[0083]Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of calcium oxide (CaO. Taekyung Industrial. Diameter about 10 μm) to 200 ml of water.

[0084]The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm.

[0085]Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the calcium oxide and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium oxide was 3.1 μm, and the average width of the organic fibers was about 678 nm.

[0086]Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of calcium oxide and organic fiber fibrils after the ball mill treatment was fin...

example 2

Preparation 2 of Filler for Papermaking

[0089]Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of ground calcium carbonate (GCC, Omyakorea Co., Ltd. Diameter 5 μm or more) to 200 ml of water. The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm. Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the ground calcium carbonate and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium carbonate was 3.2 μm, and the average width of the organic fibers was about 825 nm.

[0090]Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of ground calcium carbonate and organic fiber fibrils after the ...

example 3

Preparation 3 of Filler for Papermaking

[0093]Step 1-1: A diluted mixture was prepared by adding 5.6 g of the calcium oxide used in step 1-1 of Example 1, 30 g of the ground calcium carbonate used in step 1-1 of Example 2, and 2 g of organic fibers to 200 ml of water.

[0094]Step 1-2: Grinding was performed using a ball mill as in step 1-2 of Example 2. After grinding, the average width of the cellulose fibrils was confirmed to be 782 nm.

[0095]Step 2: Preflocs were formed in the same manner as in step 2 of Example 2.

[0096]Step 3: In the same manner as step 3 of Example 2, to make the total amount of calcium oxide 22,5 g, 16.9 g of calcium oxide, excluding the 5.6 g of calcium oxide added in the step 1-1, was additionally added so that the total amount of calcium oxide became 22.5 g, and the filler was prepared by injecting carbon dioxide into the ground calcium carbonate at 30° C. to attach it to the cellulose fibrils together with newly generated precipitated calcium carbonate. The re...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of PCT / KR2024 / 009859, filed Jul. 10, 2024, which claims the benefit of foreign priority from Korean Patent Application No. 10-2024-0089038 filed Jul. 5 2024 and Korean Patent Application No. 10-2023-0092212 filed Jul. 17, 2023, the entire contents of each of which are incorporated herein by reference.FIELD

[0002] The present disclosure relates to a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound, and a use thereof.BACKGROUND

[0003] The raw materials used for manufacturing printing paper include wood pulp, fillers, and other additives. Among these, wood pulp is used as the main raw material, and next, the content of the filler is high. The filler is also used to improve paper qualities such as opacity, brightness, and printability, but because the price of the filler is lower compared to wood pulp, a cost-saving effect can also be expected due to the replacement of pulp.

[0004] Recently, in the paper industry, as the price of not only pulp raw materials but also oil is on an increasing trend, the development of technology for the efficient utilization of fillers, which are not only cheaper than pulp but also advantageous compared to pulp in terms of drying load, can be said to be a very important task. However, because these fillers have disadvantages such as hindering the formation of hydrogen bonds between fibers and reducing the tensile strength and stiffness of the paper, the use of fillers has been limited. To overcome problems such as the above, various measures have been sought. To prevent a decrease in paper strength while increasing the filler content, many technologies such as a mixture of pulp and filler (fiber-filler composite), preflocculation, lumen loading, and hybrid calcium carbonate have been developed and have also been applied.

[0005] For example, the pre-flocculation technology refers to a technology that forms stabilized preflocs having a uniform size by mixing calcium carbonate and an ionic polymer to cause the calcium carbonate particles to form aggregates, and then forming a strong vortex. These preflocs are used as a raw material for papermaking, and when paper is manufactured by adding the preflocs to the raw material for papermaking, paper having a higher tensile strength than paper using ordinary calcium carbonate can be manufactured. However, its use is being limited because the bulk does not increase.

[0006] As conventional technologies for manufacturing a filler for papermaking, Korean Laid-open Patent Publication No. 2009-0040682 discloses a method for manufacturing paper to which filler pre-flocculation using amphoteric polyacrylamide is applied; Korean Laid-open Patent Publication No. 2005-0023824 discloses a method for manufacturing paper using a cationic starch; and Korean Laid-open Patent Publication No. 2015-1510313 discloses a method for manufacturing hybrid calcium carbonate in which calcium carbonate and a calcium compound are pre-flocculated with an ionic polymer, and then carbon dioxide is injected to cause the calcium carbonate and newly generated calcium carbonate to aggregate. However, a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound of the present disclosure and a use thereof have not yet been disclosed.SUMMARY

[0007] In one embodiment, the present disclosure provides a method for preparing a filler for papermaking, comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.

[0008] In another embodiment, the present disclosure provides a method for preparing a filler for papermaking, comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.DETAILED DESCRIPTION

[0009] The present disclosure has been devised in response to needs such as those described above, and the present disclosure provides a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound, and a use thereof, and the present disclosure was completed by confirming that paper manufactured using the filler prepared by the filler preparation method of the present disclosure has superior bulk and breaking length compared to paper manufactured by a conventional preparation method.

[0010] To achieve the above object, the present disclosure provides a method for preparing a filler for papermaking, comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.

[0011] According to an Example of the present disclosure, the step (1) may comprise: (1-1) a step of preparing a mixed solution having a solids content of 1 to 60 wt % by mixing organic fibers and an inorganic compound in a weight ratio of 1:5 to 100, and then adding water; and (1-2) a step of preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %, by grinding the mixed solution. In addition, the inorganic compound may be one or more selected from calcium carbonate (CaCO3), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), magnesium carbonate (MgCO3), gypsum, kaolin, calcined clay, talc, perlite, diatomaceous earth, zinc carbonate, lithium carbonate, magnesium hydroxide, and aluminum trihydrate.

[0012] In addition, the calcium carbonate may be one or more selected from ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC).

[0013] In addition, the fiber fibril may comprise one or more selected from cellulose and chitin.

[0014] In addition, the ionic polymer may be one or more selected from an anionic polymer and a cationic polymer.

[0015] In addition, the anionic polymer may be one or more selected from a polysaccharide, a protein, polyvinyl alcohol, polyvinyl acetate, a cellulose derivative, epoxy acrylate, polyester, polyurethane, polyester acrylate, polyether acrylate, a polyolefin dispersion, polyamide, a vinyl copolymer, and polyacrylate.

[0016] In addition, the cationic polymer may be one or more selected from a polyamidoamine-epihalohydrin polymer, a polyalkyldiallylamine-epihalohydrin polymer, polyethyleneimine, polyacrylamide, polyamine, polyvinylamine, and a cationic starch.

[0017] In addition, in the step (2), the amount of the ionic polymer added may be 0.01 to 10 parts by weight of one or more kinds of ionic polymers with respect to 100 parts by weight of the mixed aqueous solution.

[0018] In addition, in the step (3), the calcium compound may be one or more selected from calcium oxide, calcium hydroxide, calcium sulfate, and calcium phosphate.

[0019] In addition, the present disclosure provides a filler for papermaking, wherein a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region, and a metal carbonate has a shape in which it is disposed on the fiber fibrils, the filler for papermaking comprising 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate (this filler is hereinafter referred to as hybrid flexible calcium carbonate (HFCC)).

[0020] In addition, the present disclosure provides a method for manufacturing paper, comprising the steps of: (1) mixing 1 to 60 wt % of the above-described filler for papermaking (HFCC); and 40 to 99 wt % of beaten natural pulp or recycled pulp; and (2) introducing the mixture of the step (1) into a paper machine to manufacture paper.

[0021] In addition, the present disclosure provides a method for manufacturing ultra-high-filler-content paper, in which an inorganic material is 50 wt % or more of the total weight, the method comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking (HFCC); and 1 to 40 wt % of beaten natural pulp or recycled pulp; and adding 1 to 30% of an ionic polymer for strength enhancement; and (2) introducing the mixture of the step (1) into a paper machine to manufacture the paper.

[0022] In addition, the present disclosure provides a method for manufacturing a composite, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking (HFCC); and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the composite by impregnating, spraying, or performing curtain coating with 50 to 5000 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0023] In addition, the present disclosure provides a method for manufacturing stone paper, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the stone paper by coating or impregnating with 1 to 50 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0024] In addition, the present disclosure provides a paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate. In this case, the paper may comprise 1 to 60 wt % of the filler (HFCC).

[0025] In addition, the present disclosure provides ultra-high-filler-content paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0026] In this case, the ultra-high-filler-content paper may comprise the filler (HFCC) in an amount of 50 wt % or more based on the total weight of the ultra-high-filler-content paper.

[0027] In addition, the present disclosure provides a composite formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0028] In addition, the present disclosure provides a stone paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.Fiber Fibrils

[0029] In one embodiment, the present disclosure provides a method for manufacturing a papermaking filler using chitin fibril and paper including the papermaking filler manufactured thereby, and more specifically, to a method for manufacturing a papermaking filler using chitin fibril and paper including the papermaking filler manufactured thereby and the calcium compound.

[0030] In one embodiment, the present disclosure provides a method for manufacturing a papermaking filler comprising chitin fibrils converted from calcium carbonate and calcium carbonate by injecting carbon dioxide into a mixture after manufacturing the mixture, and a method for manufacturing paper using the same. paper using the papermaking filler manufactured by the method of the present disclosure has excellent strength properties compared to ground calcium carbonate or ground calcium carbonate pre-agglomerates, which are fillers mainly used in the related art, in strength properties such as bulk, hot-cutting, and flexural rigidity. when compared to wood nanocellulose, chitin, which is marine waste rather than wood pulp, is used, and has similar strength, but has the advantage of consuming much less energy required to manufacture chitin fibrils of the present disclosure than energy required to manufacture nanocellulose.

[0031] In one embodiment, the present disclosure provides a method for preparing a papermaking filler using chitin fibrils and paper including the papermaking filler prepared thereby, and the preparation of a filler using chitin fibrils or nano chitin fibrils according to the present disclosure can be a method for preparing a very excellent filler. Specifically, the present disclosure has completed the present disclosure by preparing a mixture of nano chitin fibrils and a calcium compound, injecting carbon dioxide into the mixture and reacting the mixture with the calcium compound to prepare a filler for papermaking, and preparing paper using the same, confirming that the strength properties such as bulk, hot-cutting, and bending rigidity of the prepared paper are excellent, and the energy required to prepare chitin fibrils of the present disclosure is much less than the energy required to prepare nanocellulose, which is a filler mainly used in the related art, thereby completing the present disclosure.

[0032] In one embodiment, the present disclosure provides a manufacturing method of the filler for the paper manufacture including the following steps: (1) manufacturing a mixture of chitin fibril and a calcium compound by adding 100 to 5000 parts by weight of water and 5 to 100 parts by weight of the calcium compound with respect to 1 part by weight of chitin fibril; and (2) the step of converting to the calcium carbonate the calcium compound the carbon dioxide is injected under the temperature condition of 10~80° C. into the mixture of the calcium compound and the chitin fibril manufactured from above statement step (1), wherein in step (1), the chitin fibril fibrillates chitin by using the refiner, grinder, super mass collider, disperser (homogenizer) or the super fluidizer; or in step (1), chitin fibril is treated with at least one acid selected from acetic acid, sulfuric acid, nitric acid, phosphoric acid, lactic acid, and citric acid to have a ph of 2 to 5, and then chitin is fibrillated using a refiner, a grinder, a super mass collider, a homogenizer, or a super fluidizer.

[0033] In step (1), the chitin fibril is preferably chitin fibril obtained by fibrillating chitin using a refiner, a grinder, a super mass collider, a homogenizer, or a super fluidizer after adding 1 to 10 parts by weight of any one selected from carboxymethyl cellulose (CMC), methyl cellulose, carrageenan, codonopsislanceolata, a cationic polymer, and an anionic polymer with respect to 100 parts by weight of chitin, but is not limited thereto.

[0034] As the cationic polymer, a polymer such as a polyamidoamine-epihalohydrin polymer, apolyalkyldiallylamine-epihalohydrin polymer, polyethyleneimine, polyacrylamide, polyamine, polyvinylamine, and cationic starch may be used.

[0035] As the anionic polymer, polysaccharides, proteins, polyvinyl alcohol, polyvinyl acetate, cellulosederivatives, epoxy acrylate, polyester, polyurethane, polyester acrylate, polyether acrylate, polyolefindispersions, polyamides, vinyl copolymers, polyacrylates, and the like may be used.

[0036] Here, examples of the polysaccharide include agar, sodium alginate, and modified starch (carboxymethylated starch, hydroxyethylated starch, oxidized starch, and the like), and the cationic polymer and the anionic polymer are not limited as long as calcium carbonate can be easily attached to the chitin fibril raw material.

[0037] The chitin is preferably α-chitin or β-chitin, but is not limited thereto. The chitin fibril may have an average width of preferably 1 μm or less, more preferably 10 to 1000 nm, even more preferably 10 to 100 nm, but is not limited thereto. In the present disclosure, according to the TAPPI standard definition, when the width of chitin fibril is 100 nm or less, it is named ‘nano chitin fibril. In addition, the present disclosure relates to a papermaking filler prepared by the method for preparing the papermaking filler.

[0038] Moreover, the present disclosure comprises the step of: (1) beating the pulp so that for the freeness, 100~500 Canadian Standard Freeness (CSF) be; and

[0039] (2) mixing the filler for the paper manufacture and the pulp beaten in step (1). The present disclosure relates to a method for manufacturing paper including the same.

[0040] In step (2) of the paper preparation method, it is preferable to further administer 0.05 to 0.5 parts by weight of the cationic polyacrylamide to the filler and the pulp based on 100 parts by weight of the dry weight of the filler and the pulp, but the present disclosure is not limited thereto.

[0041] The pulp may be natural pulp or recycled pulp, and is preferably a mixture of bleached conifer pulp and bleached broadleaf pulp, but is not limited thereto.

[0042] In the paper preparation method, the filler and the pulp are preferably mixed in a weight ratio of 1 to90:99 to 10, more preferably 30 to 50:70 to 50, and most preferably 30:70 or 50:50, but are not limited thereto.

[0043] In addition, the present disclosure relates to paper manufactured by the method for manufacturing the paper.

[0044] The present disclosure relates to a method for preparing a filler for papermaking using a mixed solution of organic fibers and an inorganic compound, and a use thereof, wherein paper comprising the filler for papermaking prepared by the preparation method according to the present disclosure has a greatly improved paper bulk compared to paper using a conventional ground calcium carbonate filler, has the effect of possessing an excellent breaking length, and comes to have a characteristic of excellent smoothness. By using these characteristics, it becomes possible to make paper of excellent quality even when using a larger amount of the filler than ground calcium carbonate, and therefore, the economic feasibility is excellent, and the effects of reducing the amount of organic fibers used and reducing drying energy can be obtained.BRIEF DESCRIPTION OF DRAWINGS

[0045] FIG. 1 is a process flowchart schematically showing a process of manufacturing paper using the filler for papermaking prepared according to the present disclosure.

[0046] FIG. 2 is a comparison of the bulk (A), breaking length (B), and internal bond strength (C) of the papers prepared in Examples 4 to 9 and Comparative Examples 1 to 4 of the present disclosure.

[0047] FIG. 3A and FIG. 3B are electron micrographs showing the timing of the carbon dioxide reaction in step 3 of Example 1 of the present disclosure, wherein FIG. 3A shows an initial state of the carbon dioxide reaction, FIG. 3B shows an intermediate state of the carbon dioxide reaction, and FIG. 3C is FIG. 3A is an electron micrograph of a final form of the carbon dioxide reaction.

[0048] FIG. 4A, FIG. 4B, and FIG. 4C provide results of confirming the bulk, flexural rigidity, and hot-cutting of paper, respectively, prepared in examples and comparative examples of the present disclosure.METHODS FOR PREPARING A FILLER FOR PAPERMAKING

[0049] The present disclosure relates to a method for preparing a filler for papermaking (HFCC), comprising the steps of: (1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %; (2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and (3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs were formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0±1.0.

[0050] In this case, the step (1) may also be performed by a method comprising: 1) preparing a separate mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100; 2) preparing by mixing an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100; or 3) mixing organic fibers and an inorganic compound and grinding to prepare a mixed aqueous solution having the same size and weight ratio.

[0051] According to an Example of the present disclosure, the step (1) may comprise: (1-1) a step of preparing a mixed solution by mixing organic fibers and an inorganic compound, and then adding water; and (1-2) a step of preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm and fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100, and having a solids content of 1 to 60 wt %, by grinding the mixed solution.

[0052] In this case, in the step (1-1), the organic fibers and the inorganic compound may be mixed in a weight ratio of 1:5 to 100, and the mixed solution may have a solids content of 1 to 60 wt %. In the step (1-2), the step of grinding the mixed solution of organic fibers and the inorganic compound not only reduces the size of the inorganic compound to an appropriate level, but also, as the organic fibers are fibrillated with low energy by friction with the inorganic compound in a strong alkaline state due to hydration of the inorganic compound, energy consumption in the preparation of the organic fiber fibrils can be greatly reduced compared to a method of separately preparing and using microfibrils or nanofibrils. The grinding is preferably performed using a grinder or a ball mill, but is not limited thereto.

[0053] In the steps (2) and (3), preflocs are prepared using the inorganic compound and the organic fiber fibrils that were mixed together, and by reacting in water through a method of adding calcium oxide thereon and injecting carbon dioxide, a metal carbonate is made to adhere to the surface of the preflocs, whereby a robust and elongated metal carbonate can be prepared.

[0054] In the present disclosure, preflocculation means changing the inorganic compound particles and the organic fiber fibrils into an aggregate by treating them with coagulants and a flocculant.

[0055] The stirring of the step (2) is preferably performed at 500 to 5,000 rpm; if stirring is performed at less than 500 rpm, a problem arises in that the physical properties of the paper deteriorate because the size of the aggregate particles formed is very large when paper is manufactured using them, and if stirring is performed at more than 5,000 rpm, a problem arises in that it is not effective because the particle size becomes too small.

[0056] The particle size of the preflocs formed in the step (2) may be 1 to 100 μm.

[0057] If the particle size of the preflocs formed in the step (2) is less than 1 μm, there is a problem that there is no effect of improving the physical properties of paper manufactured using them because the size of the preflocs is very small, and if it exceeds 100 μm, there is a problem that it is difficult for the filler to be uniformly distributed when manufacturing paper using them.

[0058] The inorganic compound may comprise one or more selected from calcium carbonate (CaCO3), calcium oxide (CaO), calcium hydroxide (Ca(OH) 2), magnesium carbonate (MgCO3), gypsum, kaolin, calcined clay, talc, perlite, diatomaceous earth, zinc carbonate, lithium carbonate, magnesium hydroxide, and aluminum trihydrate, and may preferably comprise a metal carbonate comprising one or more selected from calcium carbonate, magnesium carbonate, aluminum carbonate, lithium carbonate, and zinc carbonate, and more preferably may be calcium carbonate, but is not limited thereto.

[0059] The calcium carbonate is preferably one or more selected from ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC), but is not limited thereto, and the fiber fibril preferably comprises one or more selected from cellulose and chitin, but is not limited thereto.

[0060] The ionic polymer is preferably one or more ionic polymers selected from an anionic polymer and a cationic polymer, but is not limited thereto.

[0061] The anionic polymer is preferably one or more selected from a polysaccharide, a protein, polyvinyl alcohol, polyvinyl acetate, a cellulose derivative, epoxy acrylate, polyester, polyurethane, polyester acrylate, polyether acrylate, a polyolefin dispersion, polyamide, a vinyl copolymer, and polyacrylate, but is not limited thereto. The cationic polymer is preferably one or more selected from a polyamidoamine-epihalohydrin polymer, a polyalkyldiallylamine-epihalohydrin polymer, polyethyleneimine, polyacrylamide, polyamine, polyvinylamine, and a cationic starch, but is not limited thereto.

[0062] The amount of the ionic polymer added in the step (2) is preferably 0.01 to 10 parts by weight of the ionic polymer with respect to 100 parts by weight of the mixed aqueous solution, and more preferably 0.1 to 0.3 parts by weight of the ionic polymer, but is not limited thereto.

[0063] In the step (3), the calcium compound is preferably one or more calcium compounds selected from calcium oxide, calcium hydroxide, calcium sulfate, and calcium phosphate, and more preferably is calcium oxide or calcium hydroxide, but is not limited thereto.

[0064] In a case where calcium hydroxide is used as the calcium compound, calcium hydroxide prepared by reacting sodium hydroxide and calcium chloride may be used. That is, because calcium hydroxide can be formed by reacting sodium hydroxide and calcium chloride, calcium carbonate can be formed by reacting with carbon dioxide even without directly adding calcium hydroxide.

[0065] In the step (3), the calcium contained in the calcium compound component is dissolved in the form of a salt such as calcium hydroxide in the diluted solution in which the preflocs are formed, and calcium carbonate can be synthesized through a carbonation reaction by injecting carbon dioxide thereinto. In this case, it is preferable to react the carbon dioxide until the pH of the diluted solution generally reaches 7.0, and it is necessary to carry out the reaction until the injected carbon dioxide no longer reacts. In addition, in the step (3), the temperature for reacting the diluted solution by injecting carbon dioxide is preferably 10 to 80° C.

[0066] In addition, the present disclosure provides a filler for papermaking, wherein a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region, and a metal carbonate has a shape in which it is disposed on the fiber fibrils, the filler comprising 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0067] As the filler has a structure in which the metal carbonate is disposed on the fiber fibrils, when forming paper comprising the same, the bulk of the paper is greatly improved, it has an excellent breaking length, and it may be more advantageous in terms of having excellent smoothness. In addition, as the filler satisfies the content range of the fiber fibrils and the metal carbonate, when forming paper comprising the same, the bulk of the paper is greatly improved, it has an excellent breaking length, and it may be more advantageous in terms of having excellent smoothness.

[0068] In addition, the present disclosure provides a method for manufacturing paper, comprising the steps of: (1) mixing 1 to 60 wt % of the above-described filler for papermaking (HFCC); and 40 to 99 wt % of beaten natural pulp or recycled pulp; and (2) introducing the mixture of the step (1) into a paper machine to manufacture paper.

[0069] In addition, the present disclosure provides a method for manufacturing ultra-high-filler-content paper, in which an inorganic material is 50 wt % or more of the total weight, the method comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; and adding 1 to 30% of an ionic polymer for strength enhancement; and (2) manufacturing the ultra-high-filler-content paper by introducing the mixture of the step (1) into a paper machine.

[0070] In addition, the present disclosure provides a method for manufacturing a composite, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the composite by performing impregnation, spraying, and / or curtain coating with 50 to 5000 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0071] The composite is a material that exhibits new characteristics different from previous materials by combining two or more materials of different characteristics, and the difference from a synthetic material is that the constituent components are still separated and unchanged. The composite can replace metal instruments or metal sheets in airplanes or automobiles, and its uses, such as for cell phone cases, tennis rackets, golf clubs, industrial pipes or tanks, are endless, and continuous development of applications is being carried out. In the present disclosure, as a synthetic polymer or a biodegradable polymer is added to the metal carbonate, it is characterized in that high strength and dimensional stability are enhanced, and it can be used for various applications.

[0072] In addition, the present disclosure provides a method for manufacturing stone paper, comprising the steps of: (1) mixing 50 to 99 wt % of the above-described filler for papermaking and 1 to 50 wt % of beaten natural pulp or recycled pulp; (2) introducing the mixture of the step (1) into a paper machine to manufacture a paper-form sheet; and (3) after the step (2), manufacturing the stone paper by coating or impregnating with 1 to 50 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

[0073] Although the stone paper uses the name ‘paper’, it is something that can replace paper or plastic. The stone paper is robust, and although it has waterproof properties, it has a characteristic of decomposing in a short time like a biodegradable plastic after use; it can be processed into various forms and can be folded, and its printability is superior to that of ordinary paper.

[0074] Currently manufactured stone papers have a density of 1.0 or more and thus have the disadvantage of being heavy when making books or printed materials, but the stone paper using the metal carbonate manufactured in the present disclosure has a density of 1.0 or less and thus can be comparable to ordinary paper, and as it has high hydrophobicity, high-grade printability, and biodegradability, it is an inexpensive material that can replace non-degradable plastics or paper that uses wood.

[0075] In addition, the present disclosure provides a paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate. In this case, the paper may comprise 1 to 60 wt % of the filler (HFCC).

[0076] In addition, the present disclosure provides ultra-high-filler-content paper formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0077] In this case, the ultra-high-filler-content paper comprises the filler (HFCC) in an amount of 50 wt % or more based on the total weight of the ultra-high-filler-content paper.

[0078] In addition, the present disclosure provides a composite characterized in that the composite is formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0079] In addition, the present disclosure provides a stone paper characterized in that the stone paper is formed comprising a filler, wherein the filler has a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region and a metal carbonate is disposed on the fiber fibrils, and wherein the filler comprises 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

[0080] As the paper and the ultra-high-filler-content paper use the filler (HFCC), the bulk is greatly improved, they have an excellent breaking length, and they may be more advantageous in terms of having excellent smoothness.

[0081] In addition, as the filler satisfies the weight range of the fiber fibrils and the metal carbonate, it may be more advantageous in terms of manufacturing a biocomposite and a stone paper.EXAMPLES

[0082] Hereinafter, the present disclosure will be described in more detail using Examples. It is apparent to a person having ordinary skill in the art to which the present disclosure pertains that these Examples are only for describing the present disclosure more specifically, and the scope of the present disclosure is not limited by them.Example 1. Preparation 1 of Filler for Papermaking

[0083] Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of calcium oxide (CaO. Taekyung Industrial. Diameter about 10 μm) to 200 ml of water.

[0084] The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm.

[0085] Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the calcium oxide and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium oxide was 3.1 μm, and the average width of the organic fibers was about 678 nm.

[0086] Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of calcium oxide and organic fiber fibrils after the ball mill treatment was finished, 0.1 parts by weight of a cationic polymer, polyacrylamide (PAM, Ciba Chemical Korea), was added to impart a weak cationic property, and thereafter, in a state where a vortex was formed, with respect to 100 parts by weight of total solids, 0.1 parts by weight of an anionic polymer, a micropolymer (Eka Chemical Korea), was added so that the overall zeta potential, that is, the charge, maintained neutrality. Here, the precise amount of ionic polymer added was based on the zeta potential. Thereafter, the diluted solution was stirred at a rotation speed of 2,000 rpm for 10 minutes to form preflocs.

[0087] Step 3: After the step 2, after additionally adding 5 g of calcium oxide to the mixed aqueous solution, the filler for papermaking was prepared by continuously injecting carbon dioxide into the diluted solution while stirring at 2000 rpm at 30° C. until the pH reached 7.0. Here, the reaction endpoint was also set as the point at which the injection rate and the discharge rate of carbon dioxide became equal.

[0088] In this case, a total amount of 45 g of calcium oxide reacted to form 80 g of precipitated calcium carbonate, thereby forming a filler attached to 2 g of cellulose fibrils (cellulose fibrils: precipitated calcium carbonate=1:40).Example 2. Preparation 2 of Filler for Papermaking

[0089] Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of ground calcium carbonate (GCC, Omyakorea Co., Ltd. Diameter 5 μm or more) to 200 ml of water. The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm. Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the ground calcium carbonate and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium carbonate was 3.2 μm, and the average width of the organic fibers was about 825 nm.

[0090] Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of ground calcium carbonate and organic fiber fibrils after the ball mill treatment was finished, 0.1 parts by weight of a cationic polymer, polyacrylamide (PAM, Ciba Chemical Korea), was added to impart a weak cationic property, and thereafter, in a state where a vortex was formed, with respect to 100 parts by weight of total solids, 0.1 parts by weight of an anionic polymer, a micropolymer (Eka Chemical Korea), was added so that the overall zeta potential, that is, the charge, maintained neutrality. Here, the precise amount of ionic polymer added was based on the zeta potential.

[0091] Thereafter, the diluted solution was stirred at a rotation speed of 2,000 rpm for 10 minutes to form ground calcium carbonate-cellulose fibril preflocs.

[0092] Step 3: After adding 22.5 g of calcium oxide to the preflocs formed in the step 2 under a vortex of 2,000 rpm at 30° C., the filler for papermaking was prepared by continuously injecting carbon dioxide into the diluted solution until the pH reached 7.0. Here, the reaction endpoint could also be set as the point at which the injection rate and the discharge rate of carbon dioxide became equal. In this case, 40 g of ground calcium carbonate and 40 g of newly generated precipitated calcium carbonate formed a filler (HFCC) attached to the surface of the cellulose fibrils.Example 3. Preparation 3 of Filler for Papermaking

[0093] Step 1-1: A diluted mixture was prepared by adding 5.6 g of the calcium oxide used in step 1-1 of Example 1, 30 g of the ground calcium carbonate used in step 1-1 of Example 2, and 2 g of organic fibers to 200 ml of water.

[0094] Step 1-2: Grinding was performed using a ball mill as in step 1-2 of Example 2. After grinding, the average width of the cellulose fibrils was confirmed to be 782 nm.

[0095] Step 2: Preflocs were formed in the same manner as in step 2 of Example 2.

[0096] Step 3: In the same manner as step 3 of Example 2, to make the total amount of calcium oxide 22,5 g, 16.9 g of calcium oxide, excluding the 5.6 g of calcium oxide added in the step 1-1, was additionally added so that the total amount of calcium oxide became 22.5 g, and the filler was prepared by injecting carbon dioxide into the ground calcium carbonate at 30° C. to attach it to the cellulose fibrils together with newly generated precipitated calcium carbonate. The reason for adding the calcium oxide in divided portions in this manner is to maintain an alkaline state during the ball mill treatment to aid in the fibrillation of the organic fibers.Example 4. Preparation 1 of Paper Comprising Filler for Papermaking

[0097] Step 1: As pulp for making paper, bleached softwood pulp and bleached hardwood pulp were mixed at a ratio of 2:8, and after performing beating so that the freeness became 500 ml CSF (Canadian Standard Freeness), the filler for papermaking prepared in Example 1 and the pulp were mixed at a weight ratio of 25:75.

[0098] Step 2: Using the filler for papermaking and the pulp mixed in the step 1, paper having a basis weight of 60 g / m2 was manufactured according to a paper testing method (ISO 5269 / 1) (FIG. 1).Example 5. Preparation 2 of Paper Comprising Filler for Papermaking

[0099] Paper was manufactured under the same conditions as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 1 and the pulp were mixed at a weight ratio of 35:65.Example 6. Preparation 3 of Paper Comprising Filler for Papermaking

[0100] Paper was manufactured under the same conditions as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 2 was used.Example 7. Preparation 4 of Paper Comprising Filler for Papermaking

[0101] Paper was manufactured in the same manner as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 2 and pulp were mixed at a weight ratio of 35:65.Example 8. Preparation 5 of Paper Comprising Filler for Papermaking

[0102] Paper was manufactured by performing in the same manner as in Example 4, except that the filler for papermaking used in step 1 of Example 4 was the filler for papermaking prepared in Example 3.Example 9. Preparation 6 of Paper Comprising Filler for Papermaking

[0103] Paper was manufactured in the same manner as in Example 4, except that in step 1 of Example 4, the filler for papermaking prepared in Example 3 and pulp were mixed at a weight ratio of 35:65.Comparative Example 1

[0104] Step 1: As pulp for manufacturing paper, bleached softwood pulp and bleached hardwood pulp were mixed at a ratio of 2:8, and beating was performed so that the freeness became 500 ml CSF (Canadian Standard Freeness).

[0105] Step 2: Ground calcium carbonate (GCC, Omyakorea Co., Ltd. 2 to 3 μm) as a filler and the pulp beaten in the step 1 were mixed at a weight ratio of 25:75, and paper having a basis weight of 60 g / m2 was manufactured according to a paper testing method (ISO 5269 / 1).Comparative Example 2

[0106] Paper was manufactured under the same conditions as in the Comparative Example 1, with the exception that in step 2 of the Comparative Example 1, the filler and the pulp were mixed at a weight ratio of 35:65.Comparative Example 3

[0107] Paper was manufactured under the same conditions as in the Comparative Example 1, with the exception that in step 2 of the Comparative Example 1, precipitated calcium carbonate (PCC, manufactured by Artone Paper. About 1.5 μm) was used instead of ground calcium carbonate.Comparative Example 4

[0108] Paper was manufactured under the same conditions as in the Comparative Example 1, with the exceptions that in step 2 of the Comparative Example 1, precipitated calcium carbonate (PCC, manufactured by Artone Paper. About 1.5 μm) was used instead of ground calcium carbonate, and the filler and the pulp were mixed at a weight ratio of 35:65.

[0109] The GCC filler used in the Comparative Examples 1 and 2 was a filler mainly used in a general wood-free paper factory, and the PCC filler used in the Comparative Examples 3 and 4 is a high-grade filler used to increase bulk and brightness more than GCC.Experimental Example 1. Analysis of Paper Characteristics

[0110] To analyze the characteristics of the paper manufactured comprising the filler for papermaking according to the present disclosure, the following experiments were conducted.(1) Analysis of Bulk and Breaking Length of Paper

[0111] To evaluate the effectiveness of the papers prepared in Examples and Comparative Examples according to the present disclosure, the bulk and breaking length of the prepared papers were analyzed. The basis weight of the paper prepared in Examples 4-9 and Comparative Examples 1 to 4 was 60 g / m2. In addition, the bulk and breaking length were analyzed. The bulk was obtained by measuring the density of the paper (unit g / cm3) and then taking the reciprocal (bulk unit cm3 / g). The breaking length (unit km) is a value obtained by dividing the tensile strength (unit kN / m) by the basis weight of the paper, and as a value that eliminates the influence of the deviation of the basis weight in the comparison of tensile strength, it can be said to be a more reliable value in the comparison of strength.

[0112] As a result, as shown in Table 1 below, the bulk of the paper prepared with GCC (ground calcium carbonate) in Comparative Example 1 and Comparative Example 2 was 1.71 and 1.68, respectively, which was much lower than the bulk of the paper prepared in Examples 4 to 9, which was 1.86 to 1.92, and this leads to a very large difference in thickness and bending stiffness, which are important physical properties of actual paper. In particular, since bending stiffness is proportional to the third power of the paper thickness, a very large difference in bending stiffness occurs (Table 1).

[0113] Since the bending stiffness decreases when the filler content is increased, this is an important reason why the filler content cannot be increased, but it was confirmed that the filler according to the present disclosure exhibits a very high bending stiffness (bending stiffness of Examples 4 to 9 was 550 to 680; bending stiffness of Comparative Examples 1 and 2 was 150 to 250).

[0114] The bulk of the paper prepared using PCC (precipitated calcium carbonate) in Comparative Examples 3 and 4 was 1.84 and 1.83, respectively, which can exhibit a higher bulk than ground calcium carbonate, and it can be seen that it exhibits a bulk value similar to the bulk of Examples 4 to 9.

[0115] However, it can be confirmed that precipitated calcium carbonate (PCC) has a very low tensile strength compared to Examples 4 to 9 (Table 1 and FIG. 2).

[0116] In addition, as shown in Table 1 below, the breaking length of the paper manufactured using ground calcium carbonate (GCC) in Comparative Example 1 and Comparative Example 2 was shown to be 2.18 when 25% of filler was added, and 1.84 when 35% was added. The breaking length of the paper manufactured in Examples 4 to 9 was shown to be 3.13 to 3.53 when 25% of filler was added, and 3.07 to 3.14 when 35% of filler was added, and thus, compared to Comparative Examples 1 to 2, it was confirmed that the breaking length of Examples 4 to 9 of the present disclosure was significantly higher under the same filler content.

[0117] In the case of the breaking length of paper manufactured using precipitated calcium carbonate (PCC), it was 1.88 when 25% of filler was added and 1.65 when 35% was added, which was lower under the same filler content than in the case of Examples 4 to 9 or even in the case of Comparative Example 1 and Comparative Example 2 using ground calcium carbonate (GCC). Accordingly, it could be confirmed that the paper manufactured using the filler for papermaking according to the present disclosure has high bulk and breaking length. FIG. 2 compared the bulk, breaking length, and internal bond strength when 25% and 35% of filler were added. It was confirmed that the bulk, breaking length, and internal bond strength of Examples 4 to 9 were all higher than in the case of using ground calcium carbonate or precipitated calcium carbonate as a filler.(2) Analysis of Brightness and Smoothness of Paper

[0118] To evaluate the effectiveness of the papers prepared in Examples and Comparative Examples according to the present disclosure, the brightness and smoothness of the prepared papers were analyzed. Specifically, the brightness analysis was measured using the ISO 2470 method, which is a method for measuring paper brightness, and the smoothness was measured using the Bekk smoothness method TAPPI T479 cm-99.

[0119] As a result, as disclosed in Table 1 below, Comparative Example 1 and Comparative Example 2 used ground calcium carbonate, and the brightness showed an average of 86.3%. Comparative Example 3 and Comparative Example 4 used precipitated calcium carbonate, and showed an average brightness of 88.8%. That is, precipitated calcium carbonate showed a significantly higher brightness than ground calcium carbonate. The average brightness of Examples 4 and 5 was 88.5%, which was higher than in the case of ground calcium carbonate and was at a level similar to that of precipitated calcium carbonate. However, the average brightness of Examples 6 and 7 was 87.3%, which was lower than in the case of using only precipitated calcium carbonate. The average brightness of Examples 8 and 9 was 88.8%, which was at a level similar to the brightness of precipitated calcium carbonate, and it was judged that this result was due to the effect of precipitated calcium carbonate being mainly synthesized and attached to the filler surface of Examples 8 and 9. It was judged that the case of Examples 6 and 7 was due to a significant amount of ground calcium carbonate being included.

[0120] It could be seen that the paper comprising HFCC, which is the filler for papermaking according to the present disclosure, has superior bulk, breaking length, and bending stiffness than in the case of ground calcium carbonate or precipitated calcium carbonate, and has a characteristic in that brightness and smoothness are maintained.TABLE 1Results of Paper Characteristic AnalysisInternalBondBendingFiller:PulpBreakingTensileStrengthStiffnessType ofType ofMixingBrightnessBulkLengthStrengthSmoothness*(lbfft / (GurleyPaperFillerRatio(%)(cc / g)(km)(kN / m)(sec)in2 × 1000)unit)Example 4Example 125:7588.81.893.452.0312.375.8652.4Example 5Example 135:6588.11.913.131.8413.871.5565.3Example 6Example 225:7587.41.863.131.8515.777.2621.5Example 7Example 235:6587.21.863.071.8115.574.3548.6Example 8Example 325:7588.81.883.532.0814.874.3635.8Example 9Example 335:6588.91.893.141.8513.272.1568.2ComparativeGCC25:7586.21.712.181.2813.468.5245.6Example 1ComparativeGCC35:6586.31.681.841.0812.765.2168.2Example 2ComparativePCC25:7588.61.841.881.1114.566.3235.6Example 3ComparativePCC35:6589.11.831.650.9515.862.5142.8Example 4(3) Evaluation of Shape and Composition of Filler

[0121] With respect to the filler for papermaking prepared in Examples 1 to 3, by observing through an electron microscope during the intermediate process of filler formation, the process of calcium carbonate attaching and forming on the central region of a plurality of fiber fibrils could be confirmed, and this is shown in FIG. 3. As seen in FIG. 3, when calcium carbonate is formed on the fiber fibrils, it can be seen that a plurality of fiber fibrils is involved, and when sufficient calcium carbonate is attached, the appearance of the fiber fibrils is no longer visible. As a result, it was confirmed that the filler for papermaking prepared in Examples 1 to 3 has a plurality of fiber fibrils present in a central region, and has a shape in which calcium carbonate is attached to the fiber fibrils.

[0122] Also, the fiber fibril and metal carbonate content were measured using the standard method TAPPI T211 om-02 (Ash in wood, pulp and paperboard: combustion at 525° C.). That is, from a filler sample using the prepared calcium carbonate metal salt, moisture was removed at 105° C., and after measuring the total weight (A), it was treated again at 525° C. for 1 hour and then cooled to measure its weight (B). At this time, the calcium carbonate remains as it is, but all of the fiber fibrils are removed as water and carbon dioxide. The value (A-B) is the weight of the fiber fibrils, and B becomes the weight of the calcium carbonate.

[0123] In addition, the content of fiber fibrils and metal carbonate within the filler prepared in Examples 1 to 3 was measured, and the results are shown in Table 2 below. The specific gravity of calcite-form calcium carbonate is 2.7, and the specific gravity of cellulose is known to be 1.5.

[0124] Therefore, if the weights of the calcium carbonate and the fiber fibrils are known, their volume can be calculated.TABLE 2FiberCalciumFiberCalciumFibrilCarbonateFibrilCarbonateItem(wt %)(wt %)(vol %)(vol %)Example 13.296.85.694.4Example 24.295.87.392.7Example 33.896.26.693.4

[0125] As can be seen in Table 2 above, it could be seen that Examples 1 to 3 according to the present disclosure satisfy the content range of fiber fibrils and metal carbonate according to the present disclosure, and accordingly, it can be seen that effects of improved bulk and excellent breaking length and smoothness, as in Table 1 above, can all be expressed simultaneously.<Preparation of Ultra-High-Filler-Content Paper>

[0126] Step 1: As pulp for making ultra-high-filler-content paper, bleached softwood pulp and bleached hardwood pulp were mixed at a ratio of 5:5, and after performing beating so that the freeness became 300 ml CSF (Canadian Standard Freeness), the filler for papermaking prepared in Example 1 and pulp were mixed at a weight ratio of 60:40, and this was referred to as ‘ultra-high-filler-content paper 1’ stock. Also, the filler for papermaking and pulp were mixed at a weight ratio of 70:30, and this was referred to as ‘ultra-high-filler-content paper 2’ stock.

[0127] Step 2: To each of the ‘ultra-high-filler-content paper 1’ stock and ‘ultra-high-filler-content paper 2’ stock mixed in the step 1, 5 wt % of epoxy resin relative to the solids content was added, and paper having a basis weight of 60 g / m2 was manufactured according to a paper testing method (ISO 5269 / 1). The physical properties of the manufactured ultra-high-filler-content paper are shown in Table 3 in comparison with the physical properties of Comparative Example 2. The content of the filler included in the paper was calculated by comparing the remaining solids with the initial paper weight after reacting the paper at 525° C. for 1 hour, and is shown as ash content in Table 3. The bulk, breaking length, and smoothness of the ultra-high-filler-content paper to which 50% or more of filler was added were significantly superior to those of Comparative Example 2. Therefore, it was confirmed that the filler prepared in Example 1 can be used for the preparation and use of ultra-high-filler-content paper.TABLE 3Comparison of Physical Properties of Ultra-High-Filler-Content PaperFiller:PulpAshBreakingTensileType ofType ofMixingContentBrightnessBulkLengthStrengthSmoothness*PaperFillerRatio(wt %)(%)(cc / g)(km)(kN / m)(sec)Ultra-high-Example60:4057.588.81.982.451.4342.3filler-content1paper 1Ultra-high-Example70:3066.789.12.102.131.2544.8filler-content1paper 2ComparativeGCC35:6533.286.31.681.841.0812.7Example 2Preparation Example 2: Preparation of Composite

[0128] Step 1: To prepare a sheet for making a biocomposite, after performing beating on bleached softwood pulp so that the freeness became 300 ml CSF (Canadian Standard Freeness), it was mixed with the filler for papermaking prepared in Example 1 at a weight ratio of 10:90 (beaten bleached softwood pulp: filler of Example 1), and to this stock, 8 wt % of epoxy resin relative to the solids content was added to prepare a paper specimen having a basis weight of 80 g / m2 according to a paper testing method (ISO 5269 / 1).

[0129] Step 2: After melting PLA at 220 to 240° C., curtain coating was performed at 350 g / m2 on the paper prepared in step 1 to prepare a ‘biocomposite’. For comparison, a sheet was prepared with only PLA at 430 g / m2 without a paper specimen, and was referred to as ‘biocomposite PLA’.

[0130] The temperature of the nozzle was maintained at 240° C. In the case of the paper specimen, coating was performed with the temperature raised to 100° C., a vacuum plate was applied to the side opposite to where the coating was performed, and a vacuum of 0.6 atm was maintained to adjust for effective internal penetration of the PLA.

[0131] Step 3: The biocomposite was completed after smoothing the surface of the paper specimen, into which the PLA had sufficiently penetrated, using a roller.

[0132] The weight and density of the prepared biocomposite were measured at room temperature, the PLA content was calculated, and the content of calcium carbonate was measured by measuring the weight after treating at 525° C. for 3 hours. In addition, the tensile strength was measured and is shown in Table 4.TABLE 4Physical Properties of BiocompositeAshBasisTensileElonga-PLAType ofType ofContentWeightStrengthtionContentPaperFiller(wt %)(g / m2)(MPa)(%)(wt %)BiocompositeExam-17.2433.334.72.381.5ple 1Biocomposite00.1430.00.00.0100.0PLA

[0133] In Table 4, because the Biocomposite PLA was very brittle, it was impossible to measure the tensile strength. On the other hand, the Biocomposite recorded an elongation, which is the strain at the point of fracture by tensile force, of 2.3%. As the Biocomposite PLA recorded an elongation of 0.0, it did not exhibit any tensile stress at all. The tensile strength of the Biocomposite was recorded as 34.7 MPa, and thus it was not significantly different from a general PLA composite.Preparation Example 3: Preparation of Stone Paper

[0134] Step 1: To prepare a sheet for making stone paper, after performing beating on bleached softwood pulp so that the freeness became 300 ml CSF (Canadian Standard Freeness), it was mixed with the filler for papermaking prepared in Example 1 at a weight ratio of 10:90 (beaten bleached softwood pulp: filler of Example 1), and to this stock, 8 wt % of epoxy resin relative to the solids content was added to prepare a paper specimen having a basis weight of 80 g / m2 according to a paper testing method (ISO 5269 / 1).

[0135] Step 2: After melting HDPE having a density of 0.935 g / cm3 at 200 to 220° C., curtain coating was performed in an amount of 20 g / m2 on the paper prepared in step 1. At this time, with the temperature of the paper specimen raised to 100° C., a vacuum plate of 0.6 atm was applied to the side opposite to the surface where the coating was performed to adjust for effective internal penetration of the HDPE.

[0136] Step 3: The ‘stone paper’ was completed after smoothing the surface of the paper specimen, into which the HDPE had sufficiently penetrated, using a roller.

[0137] The weight and density of the prepared stone paper were measured at room temperature, the HDPE content was calculated, and the content of calcium carbonate was measured by measuring the weight after treating at 525° C. for 1 hour. In addition, the tensile strength was measured and is shown in Table 5.TABLE 5Comparison of Physical Properties of Stone PaperAshBasisTensileHDPEType ofType ofContentWeightDensityStrengthContentPaperFiller(wt %)(g / m2)(cc / g)(kN / m)(wt %)Stone PaperExample73.2101.30.8852.4618.51ComparativeGCC33.260.20.5951.080.0Example 2Preparation Example 1. Preparation of Chitin Fibril Raw Material

[0138] Beta-Chitin was added to a super mass colloider and passed through the super mass colloider three times repeatedly to prepare chitin fibrils, and it was confirmed with an electron microscope that the prepared chitin fibrils had an average width of 1 μm or less.Preparation Example 2. Preparation of Nanokitin Fibril Raw Material

[0139] Beta-chitin was added to a super mass colloider and passed through the super masscolloider nine times repeatedly to prepare nano chitin fibrils, and it was confirmed by electron microscopy that the average width of the prepared nanochitin fibrils was 100 nm or less. The fibrillation energy required to prepare β-chitin into nanochitin fibrils was measured at 3 mwh / ton.Preparation Example 3. Preparation of Acid-Treated Chitin Fibril Raw Material

[0140] After β-chitin was treated with acetic acid at pH 3 for 24 hours, it was put into a super mass colloider and passed once to prepare chitin fibrils, and it was confirmed by electron microscopy that the average width of the prepared fibrils was 1 μm or less.Manufacturing Example 4. Preparation of Acid-Treated Nanochitin Fibril Raw Material

[0141] After β-chitin was treated with acetic acid at pH 3 for 24 hours, it was put into a super mass colloiderand passed twice repeatedly to prepare nanochitin fibrils, and it was confirmed with an electron microscope that the prepared fibrils had an average width of 100 nm or less.Example 11. Preparation of Papermaking Filler 11(1) Based on 1 part by weight of chitin fibril prepared in preparation example 11, 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to prepare a mixture.

[0143] (2) while stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare filler 11 for papermaking having a weight ratio of chitin fibril:calcium carbonate of 1:80.Example 12. Preparation of Papermaking Filler 12(1) 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to 1 part by weight of the nanochitin fibril prepared in preparation example 12 to prepare a mixture.

[0145] (2) while stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxidewas converted into calcium carbonate (CaCO3) to prepare filler 12 for papermaking having a weight ratioof nanochitin fibril: calcium carbonate of 1:80.Example 13. Preparation of Papermaking Filler 13(1) Based on 1 part by weight of chitin fibril prepared in preparation example 3, 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to prepare a mixture.

[0147] (2) While stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare filler 13 for papermaking having a weight ratio of chitin fibril:calcium carbonate of 1:80.Example 14. Preparation of Papermaking Filler 14(1) 1000 parts by weight of water and 45 parts by weight of calcium oxide (CaO) were added to 1 part by weight of the nanochitin fibril prepared in preparation example 4 to prepare a mixture.

[0149] (2) While stirring the mixture obtained in step (1) at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare filler 14 for papermaking having a weight ratio of nanochitin fibril:calcium carbonate of 1:80.Example 15. Preparation of Paper Comprising Pulp and Filler 11 for Paper Making Mixed at a Weight Ratio of 30:70(1) Bleached coniferous pulp and bleached broadleaf pulp for paper preparation were mixed at a weight ratio of 2:8 to prepare a beaten pulp having a freeness of 500 Canadian Standard Freeness (CSF).

[0151] (2) The papermaking filler 1 prepared in example 11 and the pulp beaten in step (1) were mixed at a weight ratio of 30:70.

[0152] (3) Paper was prepared according to a paper test method (ISO 5269 / 1) using a papermaking filler and pulp mixed at a weight ratio of 30:70 after step (2).

[0153] At this time, in order to improve the retention rate of the filler as a whole, 0.1 parts by weight of cationic polyacrylamide (PAM, Korean Ciba Chemical Co., Ltd.) was administered as a retention agent based on 100 parts by weight of the dry weight of the furnish (filler and pulp).Example 16. Preparation of Paper Comprising Pulp and Filler 11 for Papermaking Mixed at a Weight Ratio of 50:50

[0154] Paper was prepared in the same manner as in example 15, except that the papermaking filler 11 prepared in example 11 and the pulp were mixed in a weight ratio of 50:50 in step (2) of example 15.Example 17. Preparation of Paper Comprising Pulp and Filler 12 for Papermaking Mixed at a Weight Ratio of 30:70

[0155] Paper was prepared in the same manner as in example 15, except that the papermaking filler 12 and the pulp prepared in example 12 were mixed in a weight ratio of 30:70 in step (2) of example 5.Example 18. Preparation of Paper Comprising Pulp and Filler 12 for Papermaking Mixed at a Weight Ratio of 50:50

[0156] Paper was prepared in the same manner as in example 15, except that in step (2) of example 15, the papermaking filler 12 and the pulp prepared in example 12 were mixed at a weight ratio of 50:50.Example 19. Preparation of Paper Comprising Pulp and Filler 13 for Paper Making Mixed at a Weight Ratio of 30:70

[0157] Paper was prepared in the same manner as in example 15, except that the papermaking filler 13 and the pulp prepared in example 13 were mixed in a weight ratio of 30:70 in step (2) of example 15.Example 20. Preparation of Paper Comprising Pulp and Filler 13 for Papermaking Mixed at a Weight Ratio of 50:50

[0158] Paper was prepared in the same manner as in example 15, except that the papermaking filler 13 and the pulp prepared in example 13 were mixed in a weight ratio of 50:50 in step (2) of example 15.Example 21. Preparation of Paper Comprising Pulp and Filler 14 for Papermaking Mixed at a Weight Ratio of 30:70

[0159] Paper was prepared in the same manner as in example 15, except that the papermaking filler 14 and the pulp prepared in example 14 were mixed in a weight ratio of 30:70 in step (2) of example 15.Example 22. Preparation of Paper Comprising Pulp and Filler 14 for Papermaking Mixed at a Weight Ratio of 50:50

[0160] Paper was prepared in the same manner as in example 115, except that the papermaking filler 4 and the pulp prepared in example 14 were mixed in a weight ratio of 50:50 in step (2) of example 15.Comparative Example 11. Manufacture of Paper Using Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 30:70(1) As a pulp for making paper, bleached conifer pulp and bleached broadleaf pulp were mixed at a weight ratio of 2:8 to prepare pulp beaten to have a freeness of 500 CSF.

[0162] (2) Grond calcium carbonate (GCC) having an average particle diameter of 2 μm and the pulp beaten instep (1) were mixed at a weight ratio of 30:70.

[0163] (3) After step (2), paper was prepared according to the paper test method (iso 5269 / 1) using guround calcium carbonate (GCC) and pulp mixed at a weight ratio of 30:70.

[0164] At this time, in order to improve the retention rate of the filler as a whole, cationic polyacrylamide (PAM, Ciba Chemical Korea) as a retention agent was administered in an amount of 0.1% based on the dry weight of the furnish.Comparative Example 12. Manufacture of Paper Using Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 50:50

[0165] Paper was prepared in the same manner as in comparative example 11, except that ground calcium carbonate (GCC) having an average particle diameter of 2 μm and pulp were mixed in a weight ratio of 50:50 in step (2) of comparative example 11.Comparative Example 13. Preparation of Ground Calcium Carbonate Preaggregates(1) A dilution was prepared by mixing 50 g of ground calcium carbonate (GCC) and 500 ml of water.

[0167] (2) Polyacrylamide (PAM, Ciba Chemical, Korea), which is a cationic polymer, was added to the diluent prepared in step (1) to provide an overall zeta potential, that is, a cationic property having a weak charge, and while forming a vortex, a micro polymer (aka chemical, korea), which is an anionic polymer, was added to maintain the overall zeta potential, that is, a neutral charge. Here, the exact amount of the ionic polymer added was based on the zeta potential.

[0168] (3) After step (2), the diluted solution prepared in step (1) was stirred at a rotation speed of 2,000 rpm for 10 minutes to prepare a 35-40 μm ground calcium carbonate pre-aggregate.Comparative Example 14. Manufacture of Paper Using Pre-Aggregate of Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 30:70(1) As pulp for making paper, bleached conifer pulp and bleached broadleaf pulp were mixed at a ratio of 2:8 to prepare pulp beaten to have a freeness of 500 CSF.

[0170] (2) The ground calcium carbonate (GCC) preaggregate prepared in comparative example 3 and pulp were mixed at a weight ratio of 30:70.

[0171] (3) After step (2), paper was prepared according to the paper test method (iso 5269 / 1) using the GCC pre-aggregate and pulp mixed in step 1.

[0172] At this time, in order to improve the retention rate of the filler as a whole, 0.1% of cationic polyacrylamide (PAM, Ciba Chemical Korea) was administered as a retention agent based on the dry weight of the furnish.Comparative Example 15. Manufacture of Paper Using Pre-Aggregate of Ground Calcium Carbonate and Pulp Mixed at a Weight Ratio of 50:50

[0173] In step (2) of comparative example 14, a paper was prepared in the same manner as in comparative example 14, except that the ground calcium carbonate (GCC) preaggregate prepared in comparative example 13 and the pulp were mixed at a weight ratio of 50:50.Comparative Example 16. Preparation of Nanocellulose Filler for Papermaking Having Weight Ratio of Wood Nanocellulose:Calcium Carbonate of 1:40(1) In order to prepare wood nanocellulose, bleached broad-leaved pulp was beaten so that the freeness was 100 CSF (at this time, the beating energy was 185 kwh / ton), and this was put back into a super mass colloider and repeatedly passed through the super mass colloider 30 times to prepare nanocellulose having an average width of fibrils of 100 nm or less. At this time, it was confirmed that the required fibrillation energy was 17 mwh / ton, and the average width of fibrillation was confirmed by electron microscopy.

[0175] (2) 1000 parts by weight of water and 22.5 parts by weight of calcium oxide were added to 1 part by weight of the nanocellulose prepared in step (1) to prepare a mixture of nanocellulose and calcium oxide.

[0176] (3) While stirring the mixture of nanocellulose and calcium oxide at a speed of 300 rpm and blowing carbon dioxide (CO2), the mixture was continuously reacted until the pH of the mixture reached 7.0, and calcium oxide was converted into calcium carbonate (CaCO3) to prepare a nanocellulose filler for papermaking having a weight ratio of nanocellulose:calcium carbonate of 1:40.Comparative Example 17. Manufacture of Paper Using Nanocellulose Filler and Pulp Mixed in Weight Ratio of 30:70(1) As pulp for making paper, bleached conifer pulp and bleached broadleaf pulp were mixed at a ratio of 2:8 to prepare pulp beaten to have a freeness of 500 CSF.

[0178] (2) the nanocellulose filler prepared in comparative example 16 and the pulp were mixed at a weight ratio of 30:70.

[0179] (3) After step (2), paper was prepared according to the paper test method (iso 5269 / 1) using the nanocellulose filler and pulp mixed in step (1). At this time, in order to improve the retention rate of the filler as a whole, 0.1% of cationic polyacrylamide (pam, ciba chemical korea) was administered as a retention agent based on the dry weight of the furnish.Comparative Example 18. Manufacture of Paper Using Nanocellulose and Pulp Mixed in Weight Ratio of 50:50

[0180] In step (1) of comparative example 17, a paper was prepared in the same manner as in comparative example 17, except that the nanocellulose filler prepared in comparative example 6 and the pulp were mixed at a weight ratio of 50:50.Experimental Example 1. Characteristic Analysis of Paper

[0181] In order to analyze the properties of paper prepared by including the papermaking filler according to the present disclosure, the following experiments were performed.(1) Bulk Analysis of Paper

[0182] In order to evaluate the effectiveness of the papers prepared in examples 5 to 12 and comparative examples 11, 12, 14, 15, 17 and 18 according to the present disclosure, the bulk of the prepared papers was analyzed. In the present disclosure, bulk refers to the volume per unit mass obtained by dividing the thickness by the basis weight.

[0183] As a result, as shown in Table 6 and FIG. 4, comparative example 11, which is a paper using general ground calcium carbonate as a filler and manufactured in a weight ratio of 30:70, exhibited a bulk of 1.51 cm3 / g, and comparative example 2, which is a paper using general ground calcium carbonate as a filler and manufactured in a weight ratio of 50:50, exhibited a bulk of 1.34 cm3 / g.

[0184] In addition, comparative example 14, which is paper in which the ground calcium carbonate pre-aggregate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 30:70, exhibited a bulk of 1.48 cm3 / g, and comparative example 15, which is paper in which the ground calcium carbonate pre-aggregate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 50:50, exhibited a bulk of 1.28 cm3 / g.

[0185] Meanwhile, comparative example 17, which is a paper prepared by using the filler of comparative example 16 in which the filler and the pulp were prepared at a weight ratio of 30:70 using the filler of comparative example 16 suggesting a method of preparing the filler by using the in-situ carbonation method on the nanocellulose of the wood pulp, exhibited a bulk of 1.72 cm3 / g, and comparative example 18, which is a paper prepared by using the filler and the pulp at a weight ratio of 50:50, exhibited a bulk of 1.74 cm3 / g. From these results, it was confirmed that paper using wood nanocellulose as a filler showed high bulk.

[0186] In the case of examples 15 and 17 in which the papermaking filler comprising chitin fibrils and nanochitin fibrils according to the present disclosure prepared in examples 11 and 12 and the pulp were paper prepared at a weight ratio of 30:70, the bulk was 1.70 and 1.72 cm3 / g, respectively, and in the case of examples 16 and 18 in which the papermaking filler comprising chitin fibrils and nanochitin fibrils according to the present disclosure prepared in examples 11 and 12 and the pulp were paper prepared at a weight ratio of 50:50, the bulk was 1.75 and 1.76 cm3 / g, respectively.

[0187] The papermaking filler comprising chitin fibrils and nanochitin fibrils prepared by the acetic acid pretreatment according to the present disclosure prepared in examples 13 and 14 and the pulp of example 9 and example 11, which are paper prepared at a weight ratio of 30:70, showed bulks of 1.72 and 1.72 cm3 / g, respectively. In the case of examples 20 and 21, in which the papermaking filler comprising chitin fibrils and nanochiitin fibrils according to the present disclosure prepared in examples 3 and 4 and the pulp were paper prepared in a weight ratio of 50:50, the bulk was 1.78 and 1.79 cm3 / g, respectively.

[0188] As described above, it was confirmed that the paper using the filler made of chitin fibrils or nanochitin fibrils according to the present disclosure not only had a high bulk as the filler made of nanocellulose, but also had a higher bulk even though the content of the filler was increased from 30% to 50%.

[0189] On the other hand, when ground calcium carbonate or ground calcium carbonate preagglomerates were included, the bulk tended to decrease significantly, unlike chitin fibrils, as the content of the filler increased.(2) Comparison of Manufacturing Energy of Nanocellulose and Nanochitin Fibril

[0190] In the process of preparing the wood nanocellulose in comparative example 6, the energy (185 kwh / ton) of beating the bleached broad-leaved pulp so that the freeness reached 100 CSF and the energy of turning the super mass colloider 30 times were 17 mwh / ton. in preparation example 2 for preparing the nanochitin fibrils of the present disclosure in contrast, the beating energy was not required, and the energy required to prepare the nanochitin fibrils was confirmed to be 3 mwh / ton by turning the super mass colloider 9 times. The difference in energy required to prepare nanocellulose and nanochitin fibrils was 5 times or more, and the nanocellulose additionally required more energy to be at the bleached broadleaf pulp to 100 CSF (Table 7). Therefore, the manufacturing cost of the nanocellulose is greatly increased, and the price of the filler manufactured by the in-situ carbonation method of the nanocellulose is inevitably significantly increased. Furthermore, wood nanocellulose is inevitably seen as more eco-friendly in that it cuts and uses wood, while chitin uses marine waste(3) Hot-Cutting Analysis of Paper

[0191] In order to evaluate the effectiveness of the papers prepared in the examples according to the present disclosure and the comparative examples, the hot-cutting of the prepared papers was analyzed, and the results are shown in Table 6 and FIG. 4.

[0192] The hot-cutting is a kind of display method indicating the tensile strength of paper, the hot-cutting refers to the length of paper at the time of breaking when the end of a test piece obtained by cutting paper to a specified size is fixed and the load is gradually increased to one end and pulled, and was measured according to iso 1924-2 test standard.

[0193] As a result, as shown in Table 6, in the case of comparative example 11, which is a paper using general ground calcium carbonate as a filler and manufactured at a weight ratio of 30:70 of the filler and pulp, a hot-cutting length of 2.89 km was shown, and in the case of comparative example 12, which is a paper using general ground calcium carbonate as a filler and manufactured at a weight ratio of 50:50 of the filler and pulp, a hot-cutting length of 1.22 km was shown.

[0194] In addition, comparative example 14, which is a paper in which the ground calcium carbonate pre-agglomerate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 30:70, exhibited a hot-cutting length of 3.02 km, and comparative example 15, which is a paper in which the ground calcium carbonate pre-agglomerate prepared in comparative example 13 was used as a filler and the filler and pulp were prepared at a weight ratio of 50:50, exhibited a hot-cutting length of 1.38 km.

[0195] On the other hand, in the case of comparative example 17, which is a paper in which the filler and the pulp were prepared at a weight ratio of 30:70 using the filler of comparative example 6 which suggested a method of preparing the filler by using an in-situ carbonation method on the nanocellulose of the wood pulp, the hot-cutting length was 3.35 km, and in the case of comparative example 18, which is a paper in which the filler and the pulp were prepared at a weight ratio of 50:50, the hot-cutting length was 1.64 km. That is, it was confirmed that the filler using wood nanocellulose also showed high hot-cutting on paper.

[0196] Meanwhile, in the case of examples 15 and 17 in which the papermaking filler including chitin fibrils and nanochitin fibrils according to the present disclosure prepared in examples 11 and 12 and the pulp were manufactured at a weight ratio of 30:70, respectively, hot-molding was 3.18 and 3.38 km, and in the case of examples 16 and 18 in which the papermaking filler including chitin fibrils and nanochitin fibrilsand the pulp were manufactured at a weight ratio of 50:50 according to the present disclosure prepared in examples 11 and 12, respectively, hot-molding was 1.60 and 1.86 km.

[0197] In addition, the papermaking filler including chitin fibrils and nanochitin fibrils prepared by the acetic acid pretreatment according to the present disclosure prepared in examples 13 and 14 and the pulp of example 19 and example 11, which are paper prepared at a weight ratio of 30:70, showed hot-cutting lengths of 3.01 and 3.15 km, respectively. In the case of example 10 and example 12, in which the papermaking filler comprising chitin fibrils and nanochitin fibrils according to the present disclosure prepared in example 13 and example 14 and the pulp were prepared in a weight ratio of 50:50, respectively, hot-molding was 1.35 and 1.55 km.

[0198] It was confirmed that the paper in which the filler made of chitin fibrils or nanochitin fibrils according to the present disclosure was used as a filler for papermaking had excellent hot-cutting like the filler made of nanocellulose. In particular, it can be seen that example 17 and example 18, in which nanochitin fibrils were prepared and used without chemical treatment, showed the highest hot-cutting length under the same calcium carbonate. In general, it is common for the hot-cutting length to decrease as the bulk increases, but it is difficult to see a case in which the bulk has a high hot-cutting length at the same time, such as a case in which chitin fibrils and nanochitin fibrils are used and a case in which nanocellulose is used. These characteristics can be said to be the characteristics of fillers using chitin fibrils and nanochitin fibrils.(4) Flexural Rigidity Analysis of Paper

[0199] Flexural rigidity is an essential property for white paper, but in order to increase flexural rigidity, there was no clear method other than increasing the basis weight of paper. The flexural stiffness of the paper is usually proportional to the three squares of the bulk of the paper and the first square of the hot-cutting. The paper prepared with the papermaking filler including chitin fibrils and nanochitin fibrils suggested in the present disclosure is expected to have a much larger bulk and a large hot-cutting length compared to the paper prepared with ground calcium carbonate, and thus the flexural rigidity is expected to be significantly increased, and there are significant differences in Table 6. As a paper containing 30% of a filler using chitin fibril, example 5, example 17, example 19, and example 11 showed a flexural rigidity of 50% or more compared to comparative example 11 in which heavy calcium carbonate was used or comparative example 14 in which a pre-aggregate of ground calcium carbonate was used, and particularly, when 50% of calcium carbonate was included, an increase in flexural rigidity showed an increase of 30% to 50% or more. Even when a filler containing nanocellulose was used, high flexural rigidity was shown as in the case of using chitin fibril. Table 6.TABLE 7Result of confirming the bulk, hot-cutting, and flexural rigidity of the paperprepared in the examples and comparative examples of the present disclosureBreakingFlexuralCalciumType ofBulkLengthRigidityCarbonatefillerFiller:Pulp(cm3 / g)(km)(Gurley unit)(%)Example 5Example 1130:701.703.18625.729.8Example 6Example 1150:501.751.60352.249.8Example 7Example 1230:701.723.38647.931.1Example 8Example 1250:501.761.86403.849.9Example 9Example 1330:701.723.01615.930.5Example 10Example 1350:501.781.35405.249.2Example 11Example 1430:701.723.15653.229.5Example 12Example 1450:501.791.55398.250.8ComparativeGCC30:701.502.89425.730.8Example 11ComparativeGCC50:501.341.22219.450.1Example 12ComparativeComparative30:701.483.02418.231.5Example 14Example 3ComparativeComparative50:501.281.38208.050.4Example 15Example 3ComparativeComparative30:701.723.35632.130.5Example 17Example 6ComparativeComparative50:501.741.64389.249.8Example 18Example 6TABLE 7Comparison of energy for manufacturingof nanochitin fibrils and nanocellulosevalley beatingsuper mass colloider fibrillatedenergy (kwh / ton)energy (mwh / ton)Nanochitin Fibril03Nanocellulose18517

Examples

example 1

Preparation 1 of Filler for Papermaking

[0083]Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of calcium oxide (CaO. Taekyung Industrial. Diameter about 10 μm) to 200 ml of water.

[0084]The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm.

[0085]Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the calcium oxide and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium oxide was 3.1 μm, and the average width of the organic fibers was about 678 nm.

[0086]Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of calcium oxide and organic fiber fibrils after the ball mill treatment was fin...

example 2

Preparation 2 of Filler for Papermaking

[0089]Step 1-1: A mixed solution was prepared by adding 2 g of organic fibers and 40 g of ground calcium carbonate (GCC, Omyakorea Co., Ltd. Diameter 5 μm or more) to 200 ml of water. The organic fibers were used after beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. It was confirmed that the average width of the pulp was about 15.5 μm. Step 1-2: The mixed solution prepared in the step 1-1 was placed in a ball mill and treated for 1 hour. After the ball mill treatment was finished, the sizes of the ground calcium carbonate and the width of the organic fiber fibrils were measured with an electron microscope. As a result, it was confirmed that the average diameter of the calcium carbonate was 3.2 μm, and the average width of the organic fibers was about 825 nm.

[0090]Step 2: With respect to 100 parts by weight of total solids in the mixed aqueous solution of ground calcium carbonate and organic fiber fibrils after the ...

example 3

Preparation 3 of Filler for Papermaking

[0093]Step 1-1: A diluted mixture was prepared by adding 5.6 g of the calcium oxide used in step 1-1 of Example 1, 30 g of the ground calcium carbonate used in step 1-1 of Example 2, and 2 g of organic fibers to 200 ml of water.

[0094]Step 1-2: Grinding was performed using a ball mill as in step 1-2 of Example 2. After grinding, the average width of the cellulose fibrils was confirmed to be 782 nm.

[0095]Step 2: Preflocs were formed in the same manner as in step 2 of Example 2.

[0096]Step 3: In the same manner as step 3 of Example 2, to make the total amount of calcium oxide 22,5 g, 16.9 g of calcium oxide, excluding the 5.6 g of calcium oxide added in the step 1-1, was additionally added so that the total amount of calcium oxide became 22.5 g, and the filler was prepared by injecting carbon dioxide into the ground calcium carbonate at 30° C. to attach it to the cellulose fibrils together with newly generated precipitated calcium carbonate. The re...

Claims

1. A method for preparing a filler for papermaking of claim 12, comprising the steps of:(1) preparing a mixed aqueous solution comprising an inorganic compound having an average size of 0.1 to 10 μm, the mixed aqueous solution having a solids content of 1 to 60 wt %;(2) adding an ionic polymer to the mixed aqueous solution and stirring to form preflocs; and(3) preparing the filler for papermaking by, with respect to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution in which the preflocs are formed, adding 10 to 1000 parts by weight of a calcium compound, and then injecting carbon dioxide at 10 to 80° C. until a pH is maintained at 7.0=1.0.

2. The method of claim 1, wherein step (1) further comprises fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100 of fiber fibrils:inorganic compound.

3. The method of claim 1,wherein the step (1) comprises:(1-1) preparing a mixed solution having a solids content of 1 to 60 wt % by mixing organic fibers and an inorganic compound in a weight ratio of 1:5 to 100, and then adding water; and(1-2) preparing the mixed aqueous solution, which comprises the inorganic compound having an average size of 0.1 to 10 μm and the fiber fibrils having an average width of 5 nm to 10 μm in a weight ratio of 1:5 to 100 of fiber fibrils: inorganic compound and has a solids content of 1 to 60 wt %, by grinding the mixed solution.

4. The method of claim 1, wherein the inorganic compound is one or more selected from calcium carbonate (CaCO3), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), magnesium carbonate (MgCO3), gypsum, kaolin, calcined clay, talc, perlite, diatomaceous earth, zinc carbonate, lithium carbonate, magnesium hydroxide, and aluminum trihydrate.

5. The method of claim 3, wherein the calcium carbonate is one or more selected from ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC).

6. The method of claim 1, wherein the fiber fibril comprises one or more selected from cellulose and chitin.

7. The method of claim 1, wherein the ionic polymer is one or more selected from an anionic polymer and a cationic polymer.

8. The method of claim 6, wherein the anionic polymer is one or more selected from a polysaccharide, a protein, polyvinyl alcohol, polyvinyl acetate, a cellulose derivative, epoxy acrylate, polyester, polyurethane, polyester acrylate, polyether acrylate, a polyolefin dispersion, polyamide, a vinyl copolymer, and polyacrylate.

9. The method of claim 6, wherein the cationic polymer is one or more selected from a polyamidoamine-epihalohydrin polymer, a polyalkyldiallylamine-epihalohydrin polymer, polyethyleneimine, polyacrylamide, polyamine, polyvinylamine, and a cationic starch.

10. The method of claim 1, wherein in the step (2), an amount of the ionic polymer added is 0.01 to 10 parts by weight of one or more ionic polymers with respect to 100 parts by weight of the mixed aqueous solution.

11. The method of claim 1, wherein in the step (3), the calcium compound is one or more selected from calcium oxide, calcium hydroxide, calcium sulfate, and calcium phosphate.

12. A filler for papermaking having a structure in which a plurality of fiber fibrils having an average width of 5 nm to 10 μm are present in a central region, and metal carbonate is disposed on the fiber fibrils, and comprising 1 to 20 vol % of the fiber fibrils and 80 to 99 vol % of the metal carbonate.

13. A method for manufacturing paper, comprising the steps of:(1) mixing 1 to 60 wt % of the filler for papermaking according to claim 12; and 40 to 99 wt % of beaten natural pulp or recycled pulp; and(2) introducing the mixture of step (1) into a paper machine to manufacture paper.

14. A method for manufacturing ultra-high-filler-content paper in which an inorganic material is 50 wt % or more of a total weight thereof, the method comprising the steps of:(1) mixing 50 to 99 wt % of the filler for papermaking according to claim 12, and 1 to 50 wt % of beaten natural pulp or recycled pulp, and adding 1 to 30% of an ionic polymer for strength enhancement; and(2) introducing the mixture of step (1) into a paper machine to manufacture the ultra-high-filler-content paper.

15. A method for manufacturing a composite, comprising the steps of:(1) mixing 50 to 99 wt % of the filler for papermaking according to claims Apr. 4, 2012, and 1 to 40 wt % of beaten natural pulp or recycled pulp; and(2) introducing the mixture of step (1) into a paper machine to manufacture a paper-form sheet; and(3) after step (2), manufacturing the composite by coating or impregnating the manufactured sheet with 50 to 5000 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

16. A method for manufacturing stone paper, comprising the steps of:(1) mixing 50 to 99 wt % of the filler for papermaking according to claim 12 and 1 to 50 wt % of beaten natural pulp or recycled pulp;(2) introducing the mixture of step (1) into a paper machine to manufacture a paper-form sheet; and(3) after step (2), manufacturing the stone paper by coating or impregnating the manufactured sheet with 1 to 50 parts by weight of a synthetic polymer or a biodegradable polymer with respect to 100 parts by weight of the manufactured sheet.

17. A paper formed comprising a filler of claim 12.

18. Ultra-high-filler-content paper formed comprising a filler of claim 12,wherein an inorganic material is 50 wt % or more of a total weight of the paper.

19. A composite formed comprising a filler of claim 12.

20. A stone paper formed comprising a filler of claim 12.

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