Method for preparing filler for papermaking by using mixed solution of organic fiber and inorganic compound and application of filler

Abstract

The invention relates to a method for manufacturing a filler for papermaking by using a mixed solution of organic fibers and inorganic compounds and application of the filler. The paper comprising the filler for papermaking manufactured by the manufacturing method of the present invention has greatly improved bulk compared to the paper using the existing ground calcium carbonate filler, and thus exhibits excellent fracture length and excellent smoothness. Because of having the above-mentioned characteristics, high-quality paper can be produced even when a greater amount of filler is used with specific gravity calcium carbonate, thereby improving economic efficiency, reducing the amount of organic fibers used, and achieving energy saving in the drying process.

Description

Technical Field

[0001] This invention relates to a method for preparing paper fillers using a mixed solution of organic fibers and inorganic compounds, and its uses. Background Technology

[0002] The raw materials used to manufacture printing paper include wood pulp, fillers, and other additives. Wood pulp is used as the primary raw material, followed by fillers, which are also present in relatively high amounts. Fillers are used to improve paper qualities such as opacity, brightness, and printability. However, because fillers are cheaper than wood pulp, they can also potentially lead to cost savings by replacing wood pulp.

[0003] Recently, in the paper industry, the rising prices of both pulp raw materials and oil have made the development of technologies for the efficient use of fillers a crucial issue. These fillers should be cheaper than pulp and offer advantages in terms of drying load. However, their use is limited by drawbacks such as hindering the formation of interfiber hydrogen bonds and reducing the tensile strength and stiffness of paper. Various solutions have been explored to overcome these problems. To increase filler content while preventing a decrease in paper strength, several technologies have been developed and applied, including fiber-filler composites, preflocculation, lumen loading, and mixed calcium carbonate.

[0004] For example, preflocculation technology refers to the process of forming stable preflocculated particles of a specified size by mixing calcium carbonate with ionomers to cause the calcium carbonate particles to aggregate and then creating strong eddies. These preflocculated particles are used as raw materials for papermaking, and when paper is manufactured by adding preflocculated particles to papermaking raw materials, paper with higher tensile strength than paper using ordinary calcium carbonate can be produced. However, the application of such paper is limited because the bulk is not increased.

[0005] As prior art for manufacturing paper filling materials, Korean Patent Publication No. 2009-0040682 discloses a method for manufacturing paper using a filler with amphoteric polyacrylamide for pre-flocculation; Korean Patent Publication No. 2005-0023824 discloses a method for manufacturing paper using cationic starch; and Korean Patent Publication No. 2015-1510313 discloses a method for manufacturing mixed calcium carbonate, in which calcium carbonate and calcium compounds are pre-flocculated using an ionomer, and then carbon dioxide is injected to cause the calcium carbonate and the newly generated calcium carbonate to entangle and aggregate. However, the method of the present invention for preparing paper filling materials using a mixed solution of organic fibers and inorganic compounds, and its application, have not yet been disclosed. Summary of the Invention

[0006] The problem the invention aims to solve The present invention has been developed in response to needs such as those described above, and provides a method for preparing paper fillers using a mixed solution of organic fibers and inorganic compounds, and its use therein. The invention is completed by demonstrating that paper made using fillers prepared by the filler preparation method of the present invention has superior bulk and breaking length compared to paper made by conventional preparation methods.

[0007] means for solving problems To achieve the above objectives, the present invention provides a method for preparing a filler for papermaking, the method comprising the following steps: (1) preparing a mixed aqueous solution containing an inorganic compound with an average size of 0.1 µm to 10 µm and fibrous fibrils with an average width of 5 nm to 10 µm in a weight ratio of 1:5 to 100, and having a solid content of 1 wt% to 60 wt%; (2) adding an ionomer to the mixed aqueous solution and stirring to form a preflocculate; and (3) adding 10 parts by weight to 1000 parts by weight of a calcium compound relative to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution forming the preflocculate, and then injecting carbon dioxide at 10°C to 80°C until the pH is maintained at 7.0 ± 1.0, to prepare the filler for papermaking.

[0008] According to an embodiment of the present invention, step (1) may include: (1-1) preparing a mixed solution with a solid content of 1 wt% to 60 wt% by mixing organic fibers with inorganic compounds at a weight ratio of 1:5 to 100 and then adding water; and (1-2) preparing a mixed aqueous solution by grinding the mixed solution, the mixed aqueous solution containing inorganic compounds with an average size of 0.1 µm to 10 µm and fiber fibrils with an average width of 5 nm to 10 µm at a weight ratio of 1:5 to 100, and having a solid content of 1 wt% to 60 wt%.

[0009] In addition, the inorganic compound may be selected from one or more of 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.

[0010] Furthermore, the calcium carbonate may be selected from one or more of round calcium carbonate (GCC) and precipitated calcium carbonate (PCC).

[0011] In addition, the fibrous fibrils may comprise one or more fibrous fibrils selected from cellulose and chitin.

[0012] Furthermore, the ionic polymer may be selected from one or more of anionic polymers and cationic polymers.

[0013] Furthermore, the anionic polymer may be selected from one or more of polysaccharides, proteins, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives, epoxy acrylates, polyesters, polyurethanes, polyester acrylates, polyether acrylates, polyolefin dispersions, polyamides, vinyl copolymers, and polyacrylates.

[0014] Furthermore, the cationic polymer may be selected from one or more of polyamide amine-epiohalo alcohol polymers, polyalkyl diallylamine-epiohalo alcohol polymers, polyethyleneimine, polyacrylamide, polyamine, polyethyleneamine, and cationic starch.

[0015] Furthermore, in step (2), the amount of the added ionic polymer can be 0.01 parts by weight to 10 parts by weight of one or more ionic polymers relative to 100 parts by weight of the mixed aqueous solution.

[0016] In addition, in step (3), the calcium compound may be selected from one or more of calcium oxide, calcium hydroxide, calcium sulfate and calcium phosphate.

[0017] Furthermore, the present invention provides a papermaking filler having multiple fiber fibrils with an average width of 5 nm to 10 µm in the central region, and the fibrils being arranged in the shape of metal carbonates. The papermaking filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonates (this filler is referred to below as HFCC (hybrid flexible calcium carbonate)).

[0018] Furthermore, the present invention provides a method for manufacturing paper, the method comprising the following steps: (1) mixing 1 wt% to 60 wt% of the above-mentioned papermaking filler (HFCC) and 40 wt% to 99 wt% of beaten natural pulp or recycled pulp; and (2) adding the mixture of step (1) into a papermaking machine to manufacture paper.

[0019] Furthermore, the present invention provides a method for manufacturing paper with an ultra-high filler content in which inorganic materials account for more than 50 wt% of the total weight, the method comprising the following steps: (1) mixing 50 wt% to 99 wt% of the above-mentioned papermaking filler (HFCC) and 1 wt% to 40 wt% of beaten natural pulp or recycled pulp, and adding 1 wt% to 30% of an ionomer for strength enhancement; and (2) adding the mixture of step (1) into a papermaking machine to manufacture paper.

[0020] Furthermore, the present invention provides a method for manufacturing a composite material, the method comprising the following steps: (1) mixing 50 wt% to 99 wt% of the above-mentioned papermaking filler (HFCC) and 1 wt% to 50 wt% of beaten natural pulp or recycled pulp; (2) adding the mixture of step (1) into a papermaking machine to manufacture a sheet in the form of paper; and (3) after step (2), manufacturing the composite material by impregnating, spraying or curtain coating 50 parts by weight to 5000 parts by weight of a synthetic polymer or a biodegradable polymer relative to 100 parts by weight of the manufactured sheet.

[0021] Furthermore, the present invention provides a method for manufacturing stone paper, the method comprising the following steps: (1) mixing 50 wt% to 99 wt% of the above-mentioned papermaking filler with 1 wt% to 50 wt% of beaten natural pulp or recycled pulp; (2) adding the mixture of step (1) into a papermaking machine to manufacture a sheet in the form of paper; and (3) after step (2), manufacturing the stone paper by coating or impregnating a synthetic polymer or a biodegradable polymer with a weight of 1 to 50 parts by weight relative to 100 parts by weight of the manufactured sheet.

[0022] Furthermore, the present invention provides a paper formed by comprising a filler having multiple fibrous fibrils with an average width of 5 nm to 10 µm in the central region of the filler and being shaped as metal carbonate disposed on the fibrous fibrils, and the filler comprising 1 vol% to 20 vol% of the fibrous fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0023] In this case, the paper may contain 1 wt% to 60 wt% of the filler (HFCC).

[0024] Furthermore, the present invention provides an ultra-high filler content paper, which is formed by including a filler, wherein the central region of the filler contains multiple fiber fibrils with an average width of 5 nm to 10 µm and are in the shape of metal carbonate disposed on the fiber fibrils, and the filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0025] In this case, the ultra-high filler content paper may contain filler (HFCC) in an amount of 50 wt% or more based on the total weight of the ultra-high filler content paper.

[0026] Furthermore, the present invention provides a composite material formed by comprising a filler having multiple fibrous fibrils with an average width of 5 nm to 10 µm in the central region of the filler and being shaped as metal carbonate disposed on the fibrous fibrils, and the filler comprising 1 vol% to 20 vol% of the fibrous fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0027] Furthermore, the present invention provides a stone paper formed by comprising a filler having multiple fibrous fibrils with an average width of 5 nm to 10 µm in the central region of the filler and being shaped as metal carbonate disposed on the fibrous fibrils, and the filler comprising 1 vol% to 20 vol% of the fibrous fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0028] Invention Effects This invention relates to a method for preparing papermaking fillers using a mixed solution of organic fibers and inorganic compounds, and its applications. Paper containing the filler prepared according to the method of this invention exhibits significantly improved bulk compared to paper using conventional heavy calcium carbonate fillers, thus demonstrating excellent breaking length and smoothness. Utilizing these properties, high-quality paper can be produced even when using a larger amount of filler than heavy calcium carbonate, resulting in excellent economic feasibility, reduced organic fiber usage, and lower drying energy consumption. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the process of manufacturing paper using papermaking fillers prepared according to the present invention.

[0030] Figure 2 This is a comparison chart 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 invention.

[0031] Figure 3 These are electron microscope images showing the carbon dioxide reaction stage in step 3 of Example 1 of the present invention. Figure 3 a shows the initial state of the carbon dioxide reaction. Figure 3 b shows the intermediate state of the carbon dioxide reaction, and Figure 3 c is Figure 3 Electron micrograph of the final form of carbon dioxide reaction of α. Detailed Implementation

[0032] The present invention relates to a method for preparing a paper filling material (HFCC), the method comprising the following steps: (1) preparing a mixed aqueous solution containing an inorganic compound with an average size of 0.1 µm to 10 µm and fibrous fibrils with an average width of 5 nm to 10 µm in a weight ratio of 1:5 to 100, and having a solid content of 1 wt% to 60 wt%; (2) adding an ionomer to the mixed aqueous solution and stirring to form a preflocculation; and (3) adding 10 to 1000 parts by weight of a calcium compound relative to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution forming the preflocculation, and then injecting carbon dioxide at 10°C to 80°C until the pH is maintained at 7.0 ± 1.0, to prepare the paper filling material.

[0033] In this case, step (1) can also be performed by a method including the following steps: 1) preparing a separate mixed aqueous solution containing an inorganic compound with an average size of 0.1µm to 10µm and a fiber fibrils with an average width of 5nm to 10µm in a weight ratio of 1:5 to 100, or 2) preparing it by mixing an inorganic compound with an average size of 0.1µm to 10µm and a fiber fibrils with an average width of 5nm to 10µm in a weight ratio of 1:5 to 100, or 3) mixing and grinding organic fibers with inorganic compounds to prepare a mixed aqueous solution having the same size and weight ratio.

[0034] According to an embodiment of the present invention, step (1) may include: (1-1) preparing a mixed solution by mixing organic fibers with an inorganic compound and then adding water; and (1-2) preparing a mixed aqueous solution by grinding the mixed solution, the mixed aqueous solution comprising an inorganic compound with an average size of 0.1µm to 10µm and fiber fibrils with an average width of 5nm to 10µm in a weight ratio of 1:5 to 100, and having a solid content of 1wt% to 60wt%.

[0035] In this case, in step (1-1), organic fibers and inorganic compounds can be mixed in a weight ratio of 1:5 to 100, and the mixed solution can have a solid content of 1 wt% to 60 wt%.

[0036] In steps (1-2), the grinding of the mixed solution of organic fibers and inorganic compounds not only reduces the size of the inorganic compounds to an appropriate level, but also, due to the strongly alkaline state formed by the hydration of the inorganic compounds, allows the organic fibers to achieve fibrillation with low energy through friction with the inorganic compounds. Therefore, compared with methods that prepare and use microfibers or nanofibers separately, the energy consumption for preparing organic fiber fibrils can be greatly reduced. Preferably, the grinding is performed using a grinding mill or a ball mill, but it is not limited to these methods.

[0037] In steps (2) and (3), a preflocculated material is prepared by mixing inorganic compounds with organic fiber fibrils, and by reacting it in water with calcium oxide and carbon dioxide, metal carbonates are attached to the surface of the preflocculated material, thereby producing a strong and long metal carbonate.

[0038] In this invention, preflocculation refers to the process of treating inorganic compound particles and organic fiber fibrils with coagulants and flocculants to turn them into aggregates.

[0039] Preferably, the stirring in step (2) is carried out at 500 rpm to 5000 rpm; if the stirring is carried out at less than 500 rpm, the following problem exists: when paper is made using the formed aggregate particles, the physical properties of the paper deteriorate because the size of the formed aggregate particles is very large; and if the stirring is carried out at more than 5000 rpm, the effect is poor because the particle size becomes too small.

[0040] The particle size of the preflocculated material formed in step (2) can be from 1µm to 100µm.

[0041] If the particle size of the preflocculated material formed in step (2) is less than 1µm, the following problems exist: because the size of the preflocculated material is very small, it does not have the effect of improving the physical properties of the paper made using the preflocculated material; and if the particle size exceeds 100µm, there is a problem that the filler is difficult to distribute evenly when the paper is made using the preflocculated material.

[0042] The inorganic compound may include 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 preferably may include a metal carbonate, which includes one or more metal carbonates 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.

[0043] Preferably, the calcium carbonate is one or more calcium carbonates selected from heavy calcium carbonate (GCC) and light calcium carbonate (PCC), but not limited thereto; and preferably, the fibrous fibrils include one or more fibrous fibrils selected from cellulose and chitin, but not limited thereto.

[0044] Preferably, the ionic polymer is one or more ionic polymers selected from anionic polymers and cationic polymers, but is not limited thereto.

[0045] Preferably, the anionic polymer is one or more anionic polymers selected from polysaccharides, proteins, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives, epoxy acrylates, polyesters, polyurethanes, polyester acrylates, polyether acrylates, polyolefin dispersions, polyamides, vinyl copolymers, and polyacrylates, but is not limited thereto. Preferably, the cationic polymer is one or more cationic polymers selected from polyamide amine-epimerized alcohol polymers, polyalkyl diallylamine-epimerized alcohol polymers, polyethyleneimine, polyacrylamide, polyamine, polyethyleneamine, and cationic starch, but is not limited thereto.

[0046] Preferably, the amount of ionic polymer added in step (2) is 0.01 to 10 parts by weight relative to 100 parts by weight of the mixed aqueous solution, and more preferably, 0.1 to 0.3 parts by weight, but not limited thereto.

[0047] In step (3), preferably, the calcium compound is one or more calcium compounds selected from calcium oxide, calcium hydroxide, calcium sulfate and calcium phosphate, and more preferably, calcium oxide or calcium hydroxide, but not limited thereto.

[0048] When using the calcium hydroxide as a calcium compound, calcium hydroxide prepared by reacting sodium hydroxide with calcium chloride can be used. That is, since calcium hydroxide can be formed by reacting sodium hydroxide with calcium chloride, calcium carbonate can be formed by reacting with carbon dioxide even without directly adding calcium hydroxide.

[0049] In step (3), the calcium contained in the calcium compound component is dissolved in a diluted solution forming a preflocculated material in the form of a salt such as calcium hydroxide, and calcium carbonate can be synthesized by carbonation reaction by injecting carbon dioxide into the solution. In this case, it is preferable to allow the carbon dioxide to react until the pH of the diluted solution typically reaches 7.0, and the reaction must continue until the injected carbon dioxide no longer reacts. Furthermore, in step (3), the temperature at which the diluted solution reacts by injecting carbon dioxide is preferably between 10°C and 80°C.

[0050] Furthermore, the present invention provides a paper filler wherein a central region contains multiple fiber fibrils with an average width of 5 nm to 10 µm, and the fibrils are arranged in the shape of metal carbonates disposed on the fiber fibrils. The filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonates.

[0051] Because the filler is shaped like a metal carbonate atom set on the fiber fibrils, when paper containing this filler is formed, the paper bulk is significantly improved, the paper has excellent breaking length, and the paper has a greater advantage in terms of smoothness. Furthermore, because the filler meets the content range of the fiber fibrils and the metal carbonate, when paper containing this filler is formed, the paper bulk is significantly improved, the paper has excellent breaking length, and the paper has a greater advantage in terms of smoothness.

[0052] Furthermore, the present invention provides a method for manufacturing paper, the method comprising the following steps: (1) mixing 1 wt% to 60 wt% of the above-mentioned papermaking filler (HFCC) and 40 wt% to 99 wt% of beaten natural pulp or recycled pulp; and (2) adding the mixture of step (1) into a papermaking machine to manufacture paper.

[0053] Furthermore, the present invention provides a method for manufacturing ultra-high filler content paper, the method comprising the following steps: (1) mixing 50 wt% to 99 wt% of the above-mentioned papermaking filler with 1 wt% to 50 wt% of beaten natural pulp or recycled pulp, and adding 1 wt% to 30% of an ionomer for strength enhancement; and (2) manufacturing ultra-high filler content paper with inorganic materials accounting for 50 wt% or more of the total weight by adding the mixture of step (1) into a papermaking machine.

[0054] Furthermore, the present invention provides a method for manufacturing a composite material, the method comprising the following steps: (1) mixing 50 wt% to 99 wt% of the above-mentioned papermaking filler with 1 wt% to 50 wt% of beaten natural pulp or recycled pulp; (2) adding the mixture of step (1) into a papermaking machine to manufacture a sheet in the form of paper; and (3) after step (2), manufacturing the composite material by impregnation, spraying and / or curtain coating of a synthetic polymer or a biodegradable polymer in the amount of 50 parts by weight to 5000 parts by weight relative to 100 parts by weight of the manufactured sheet.

[0055] The composite material is a material that exhibits novel properties different from existing materials by combining two or more materials with different characteristics. The difference between this composite material and synthetic materials is that its constituent components remain separate and unchanged. This composite material can replace metal instruments or metal sheets in aircraft or automobiles, and it has limitless applications in areas such as mobile phone cases, tennis rackets, golf clubs, industrial pipes, or storage tanks, with its applications constantly being developed. In this invention, due to the addition of synthetic or biodegradable polymers to the metal carbonate, the composite material is characterized by enhanced high strength and dimensional stability and can be used in a wide variety of applications.

[0056] Furthermore, the present invention provides a method for manufacturing stone paper, the method comprising the following steps: (1) mixing 50 wt% to 99 wt% of the above-mentioned papermaking filler with 1 wt% to 50 wt% of beaten natural pulp or recycled pulp; (2) adding the mixture of step (1) into a papermaking machine to manufacture a sheet in the form of paper; and (3) after step (2), manufacturing the stone paper by coating or impregnating a synthetic polymer or a biodegradable polymer in the form of 1 to 50 parts by weight relative to 100 parts by weight of the manufactured sheet.

[0057] Although stone paper is called "paper," it is a substitute for paper or plastic. Stone paper is strong and, while waterproof, it decomposes quickly like biodegradable plastic after use. Stone paper can be processed into various shapes and folded, and its printability is superior to ordinary paper.

[0058] Currently manufactured stone paper has a density of 1.0 or greater, which results in a heavier weight when used to make books or printing materials. However, the stone paper made using metal carbonates in this invention has a density of 1.0 or less, making it comparable to ordinary paper. Furthermore, due to its high hydrophobicity, high printability, and biodegradability, this stone paper is an inexpensive alternative to non-degradable plastics or wood-based paper.

[0059] Furthermore, the present invention provides a paper formed by comprising a filler, wherein a plurality of fiber fibrils with an average width of 5 nm to 10 µm are present in the central region of the filler and are in the shape of metal carbonate disposed on the fiber fibrils, and wherein the filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0060] In this case, the paper may contain 1 wt% to 60 wt% filler (HFCC).

[0061] Furthermore, the present invention provides an ultra-high filler content paper, which is formed by including a filler, wherein the central region of the filler contains multiple fiber fibrils with an average width of 5 nm to 10 µm and are in the shape of metal carbonate disposed on the fiber fibrils, and wherein the filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0062] In this case, the ultra-high filler content paper contains 50 wt% or more of filler (HFCC) based on the total weight of the ultra-high filler content paper.

[0063] Furthermore, the present invention provides a composite material characterized in that the composite material is formed by comprising a filler, wherein the central region of the filler contains multiple fibrous fibrils with an average width of 5 nm to 10 µm and are in the shape of metal carbonate disposed on the fibrous fibrils, and wherein the filler comprises 1 vol% to 20 vol% of the fibrous fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0064] Furthermore, the present invention provides a stone paper characterized in that the stone paper is formed by comprising a filler, wherein the central region of the filler contains multiple fiber fibrils with an average width of 5 nm to 10 µm and are in the shape of metal carbonate disposed on the fiber fibrils, and wherein the filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

[0065] Because this paper and ultra-high filler content paper use filler (HFCC), the bulk is greatly improved. This paper and ultra-high filler content paper have excellent breaking length and they are more advantageous in terms of excellent smoothness.

[0066] Furthermore, since the filler meets the weight range of the fibrous fibrils and metal carbonates, it has a greater advantage in the manufacture of biocomposite materials and stone paper. Specific Implementation The present invention will now be described in more detail using embodiments. It will be apparent to those skilled in the art that these embodiments are merely for more specific description of the invention, and that the scope of the invention is not limited by these embodiments.

[0068] Example 1. Preparation of fillers for papermaking Step 1-1 A mixed solution was prepared by adding 2g of organic fiber and 40g of calcium oxide (CaO, produced by Taekyung Industrial., with a diameter of approximately 10µm) to 200ml of water.

[0069] Organic fibers were produced by beating bleached hardwood chemical pulp to a standard freeness of 200 ml CSF. The average width of the pulp was confirmed to be approximately 15.5 µm.

[0070] Step 1-2 The mixed solution prepared in step 1-1 was placed in a ball mill and processed for 1 hour. After ball milling, the size of the calcium oxide and the width of the organic fiber fimbriae were measured using an electron microscope. The results confirmed that the average diameter of the calcium oxide was 3.1 µm and the average width of the organic fibers was approximately 678 nm.

[0071] Step 2After ball milling, 0.1 parts by weight of polyacrylamide (cationic polymer) (PAM, Ciba Chemical Korea) was added relative to 100 parts by weight of the total solids in the aqueous solution of calcium oxide and organic fiber fibrils to impart weak cationicity. Subsequently, under vortex conditions, 0.1 parts by weight of a micropolymer (anionic polymer) (Eka Chemical Korea) was added relative to 100 parts by weight of the total solids to maintain an overall zeta potential (i.e., charge) neutral. The precise amount of ionic polymer added here is based on the zeta potential. The diluted solution was then stirred at 2000 rpm for 10 minutes to form a pre-flocculated solution.

[0072] Step 3 Following step 2, after adding an additional 5g of calcium oxide to the mixed aqueous solution, carbon dioxide was continuously injected into the diluted solution while stirring at 2000rpm at 30°C until the pH reached 7.0, thus preparing the papermaking filler. Here, the reaction endpoint was also set at the point where the carbon dioxide injection rate and emission rate became equal.

[0073] In this case, a total of 45g of calcium oxide reacted to form 80g of light calcium carbonate, which in turn formed a filler attached to 2g of cellulose fibrils (cellulose fibrils: light calcium carbonate = 1:40).

[0074] Example 2. Preparation of fillers for papermaking 2 Step 1-1 A mixed solution was prepared by adding 2g of organic fiber and 40g of heavy calcium carbonate (GCC, Omyakorea Co., Ltd., with a diameter of 5µm or larger) to 200ml of water.

[0075] Organic fibers were used after the bleached hardwood chemical pulp was beaten to a standard freeness of 200 ml CSF. The average width of the pulp was confirmed to be approximately 15.5 µm.

[0076] Step 1-2 The mixed solution prepared in step 1-1 was placed in a ball mill and processed for 1 hour. After ball milling, the size of the heavy calcium carbonate and the width of the organic fiber fimbriae were measured using an electron microscope. The results confirmed that the average diameter of the calcium carbonate was 3.2 µm and the average width of the organic fibers was approximately 825 nm.

[0077] Step 2After ball milling, 0.1 parts by weight of polyacrylamide (cationic polymer) (PAM, Ciba Chemical Korea) was added relative to 100 parts by weight of the total solids in the aqueous solution of the mixture of heavy calcium carbonate and organic fiber fibrils to impart weak cationicity. Subsequently, under vortex conditions, 0.1 parts by weight of a micropolymer (anionic polymer) (Eka Chemical Korea) was added relative to 100 parts by weight of the total solids to maintain an overall zeta potential (i.e., charge) neutral. The precise amount of ionic polymer added here is based on the zeta potential.

[0078] The diluted solution was then stirred at 2000 rpm for 10 minutes to form a heavy calcium carbonate-cellulose fibrillary preflocculation.

[0079] Step 3 22.5 g of calcium oxide was added to the preflocculated material formed in step 2 under vortex conditions at 30°C and 2000 rpm. Paper filling material was then prepared by continuously injecting carbon dioxide into the diluted solution until the pH reached 7.0. Here, the reaction endpoint can also be set as the point where the carbon dioxide injection rate equals the emission rate. In this case, 40 g of heavy calcium carbonate and 40 g of newly generated light calcium carbonate formed a filler (HFCC) attached to the surface of the cellulose fibrils.

[0080] Example 3. Preparation of fillers for papermaking 3 Step 1-1 A diluted mixture was prepared by adding 5.6g of calcium oxide used in step 1-1 of Example 1, 30g of heavy calcium carbonate used in step 1-1 of Example 2, and 2g of organic fiber to 200ml of water.

[0081] Step 1-2 As in steps 1-2 of Example 2, grinding was performed using a ball mill. After grinding, the average width of the cellulose fibrils was confirmed to be 782 nm.

[0082] Step 2 Preflocculation was formed in the same manner as in step 2 of Example 2.

[0083] Step 3In the same manner as step 3 of Example 2, to achieve a total calcium oxide content of 22.5 g, in addition to the 5.6 g of calcium oxide added in step 1-1, an additional 16.9 g of calcium oxide was added to bring the total calcium oxide content to 22.5 g. The filler was prepared by injecting carbon dioxide into the heavy calcium carbonate at 30°C, allowing it to adhere to the cellulose fibrils along with the newly generated light calcium carbonate. The reason for adding calcium oxide in portions in this way is to maintain an alkaline state during ball milling to facilitate the fibrillation of the organic fibers.

[0084] Example 4. Preparation of paper containing papermaking fillers 1 Step 1 As a pulp for papermaking, bleached softwood pulp and bleached hardwood pulp are mixed at a ratio of 2:8, and after beating to achieve a freeness of 500 ml CSF (Canadian Standard Freenes), the papermaking filler prepared in Example 1 is mixed with the pulp at a weight ratio of 25:75.

[0085] Step 2 Using the papermaking filler and pulp mixed in step 1, paper with a basis weight of 60 g / m² was manufactured according to paper test method (ISO 5269 / 1). Figure 1 ).

[0086] Example 5. Preparation of paper containing papermaking fillers 2 Except that in step 1 of Example 4, the papermaking filler prepared in Example 1 was mixed with the pulp at a weight ratio of 35:65, the paper was manufactured under the same conditions as in Example 4.

[0087] Example 6. Preparation of paper containing papermaking fillers 3 Except for the use of the papermaking filler prepared in Example 2 in step 1 of Example 4, paper was manufactured under the same conditions as in Example 4.

[0088] Example 7. Preparation of paper containing papermaking fillers 4 Except that in step 1 of Example 4, the paper was manufactured in the same manner as in Example 4, except that the papermaking filler prepared in Example 2 was mixed with the pulp at a weight ratio of 35:65.

[0089] Example 8. Preparation of paper containing papermaking fillers 5 Except that the papermaking filler used in step 1 of Example 4 is the papermaking filler prepared in Example 3, paper is manufactured in the same manner as in Example 4.

[0090] Example 9. Preparation of paper containing papermaking fillers 6 Except that in step 1 of Example 4, the paper was manufactured in the same manner as in Example 4, except that the papermaking filler prepared in Example 3 was mixed with the pulp at a weight ratio of 35:65.

[0091] Comparative Example 1. Step 1 As pulp for papermaking, bleached softwood pulp and bleached hardwood pulp were mixed in a ratio of 2:8 and beating was performed to achieve a freeness of 500 ml CSF (Canadian standard freeness).

[0092] Step 2 Heavy calcium carbonate (GCC, Ausnutria Korea Ltd., 2µm to 3µm) as filler was mixed with the pulp beaten in step 1 at a weight ratio of 25:75, and paper with a basis weight of 60 g / m² was produced according to the paper test method (ISO 5269 / 1).

[0093] Comparative Example 2. Except that in step 2 of Comparative Example 1, the filler and pulp were mixed at a weight ratio of 35:65, the paper was manufactured under the same conditions as in Comparative Example 1.

[0094] Comparative Example 3. Except for the following differences, the paper was manufactured under the same conditions as in Comparative Example 1: In step 2 of Comparative Example 1, light calcium carbonate (PCC, manufactured by Artone Paper, approximately 1.5 µm) was used instead of heavy calcium carbonate.

[0095] Comparative Example 4. Except for the following differences, the paper was manufactured under the same conditions as in Comparative Example 1: In step 2 of Comparative Example 1, light calcium carbonate (PCC, manufactured by Artone Paper, approximately 1.5µm) was used instead of heavy calcium carbonate, and the filler and pulp were mixed at a weight ratio of 35:65.

[0096] The GCC filler used in Comparative Examples 1 and 2 is a filler mainly used in general wood-free paper mills, while the PCC filler used in Comparative Examples 3 and 4 is an advanced filler used to further improve bulk and brightness compared to GCC.

[0097] Experimental Example 1. Analysis of Paper Properties The following experiments were conducted to analyze the properties of paper made containing the papermaking filler according to the present invention.

[0098] (1) Analysis of paper bulk and breaking length To evaluate the effectiveness of the paper prepared in the embodiments and comparative examples according to the present invention, the bulk and breaking length of the prepared paper were analyzed. The basis weight of the paper prepared in Examples 4-9 and Comparative Examples 1-4 was 60 g / m². Furthermore, the bulk and breaking length were analyzed. Bulk was obtained by measuring the density of the paper (in g / cm³) and taking its reciprocal (bulk in cm³ / g). Breaking length (in km) is the value obtained by dividing the tensile strength (in kN / m) by the basis weight of the paper. It is a value that eliminates the influence of basis weight deviation in the comparison of tensile strength, and the breaking length can be considered a more reliable value in the comparison of strength.

[0099] As shown in Table 1 below, the bulk of the paper prepared with GCC (heavy 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 (1.86 to 1.92). This resulted in 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 cube of the paper thickness, the difference in bending stiffness was very large (Table 1).

[0100] Since the flexural stiffness decreases as the filler content increases, which is an important reason why the filler content cannot be increased, the filler according to the present invention has been shown to exhibit very high flexural stiffness (the flexural stiffness of Examples 4 to 9 is 550 to 680; the flexural stiffness of Comparative Examples 1 and 2 is 150 to 250).

[0101] The bulk of the paper prepared using PCC (light calcium carbonate) in Comparative Examples 3 and 4 was 1.84 and 1.83, respectively. This paper can exhibit a higher bulk than that of heavy calcium carbonate, and it can be seen that the paper exhibits a bulk value similar to that of Examples 4 to 9.

[0102] However, it can be confirmed that, compared with Examples 4 to 9, light calcium carbonate (PCC) has a very low tensile strength (Table 1 and ...). Figure 2 ).

[0103] Furthermore, as shown in Table 1 below, the breaking length of the paper manufactured using heavy calcium carbonate (GCC) in Comparative Examples 1 and 2 is shown to be 2.18 when 25% filler is added and 1.84 when 35% filler is added. The breaking length of the paper manufactured in Examples 4 to 9 is shown to be 3.13 to 3.53 when 25% filler is added and 3.07 to 3.14 when 35% filler is added. Therefore, compared with Comparative Examples 1 to 2, it is confirmed that the breaking length of Examples 4 to 9 of the present invention is significantly higher at the same filler content.

[0104] In the case of the tearing length of paper made using light calcium carbonate (PCC), the tearing length is 1.88 when 25% filler is added, and 1.65 when 35% filler is added. Under the same filler content, the tearing length is lower than that of Examples 4 to 9, or even lower than that of Comparative Examples 1 and 2 using heavy calcium carbonate (GCC).

[0105] Therefore, it can be confirmed that paper prepared using the papermaking filler according to the present invention has high bulk and breaking length. Figure 2 The bulk, breaking length, and internal bond strength were compared when 25% and 35% filler were added. It was confirmed that the bulk, breaking length, and internal bond strength of Examples 4 to 9 were all higher than those using heavy or light calcium carbonate as filler.

[0106] (2) Analysis of paper brightness and smoothness To evaluate the effectiveness of the paper prepared in the embodiments and comparative examples according to the present invention, the brightness and smoothness of the prepared paper were analyzed. Specifically, the brightness analysis was performed using the ISO 2470 method (a method for measuring the brightness of paper), and the smoothness was measured using the Bekk smoothness method (TAPPI T479 cm-99).

[0107] As a result, as disclosed in Table 1 below, Comparative Examples 1 and 2 used heavy calcium carbonate, and the brightness was shown as an average of 86.3%. Comparative Examples 3 and 4 used light calcium carbonate, and the average brightness was shown to be 88.8%. That is, light calcium carbonate showed a significantly higher brightness than heavy calcium carbonate. The average brightness of Examples 4 and 5 was 88.5%, which was higher than that of heavy calcium carbonate and at a similar level to that of light calcium carbonate. However, the average brightness of Examples 6 and 7 was 87.3%, which was lower than that of using only light calcium carbonate. The average brightness of Examples 8 and 9 was 88.8%, which was at a similar level to that of light calcium carbonate, and this result was determined to be due to the effect of light calcium carbonate being mainly synthesized and adhering to the filler surface of Examples 8 and 9. It was determined that the cases of Examples 6 and 7 were due to the inclusion of a large amount of heavy calcium carbonate.

[0108] It can be seen that paper containing HFCC (which is a paper filling material according to the present invention) has superior bulk, breaking length and bending stiffness compared to the case of heavy calcium carbonate or light calcium carbonate, and has the characteristics of maintaining brightness and smoothness.

[0109] [Table 1] Results of paper property analysis

[0110] (3) Evaluation of the shape and composition of the packing For the papermaking fillers prepared in Examples 1 to 3, observation using an electron microscope during the intermediate process of filler formation confirmed the attachment and formation of calcium carbonate on the central region of multiple fibrils, and this process... Figure 3 As shown in [the image / document]. Figure 3 As observed, when calcium carbonate forms on the fibrils, multiple fibrils are visible, and when sufficient calcium carbonate adheres, the shape of the fibrils becomes invisible. This confirms that the paper filling materials prepared in Examples 1 to 3 have multiple fibrils in the central region, and are shaped such that calcium carbonate is attached to the fibrils.

[0111] In addition, the content of fiber fibrils and metal carbonates was measured using the standard method TAPPI T211 om-02 (Ash in wood, pulp and paperboard: combustion at 525°C). Specifically, moisture was removed from the filler sample using the prepared calcium carbonate metal salt at 105°C, and after measuring the total weight (A), the filler sample was treated at 525°C for 1 hour, then cooled to measure the weight of the filler sample (B). At this point, the calcium carbonate remained unchanged, but all fiber fibrils were removed as water and carbon dioxide. The value (AB) represents the weight of the fiber fibrils, with B representing the weight of the calcium carbonate.

[0112] Furthermore, the contents of fibrous fibrils and metal carbonates in the fillers prepared in Examples 1 to 3 were measured, and the results are shown in Table 2 below. The specific gravity of calcite-type calcium carbonate is 2.7, and the specific gravity of cellulose is known to be 1.5. Therefore, if the weights of calcium carbonate and fibrous fibrils are known, their volumes can be calculated.

[0113] [Table 2]

[0114] As can be seen from Table 2 above, all of the embodiments 1 to 3 of the present invention meet the content range of the fiber fibrils and metal carbonates according to the present invention. Therefore, it can be seen that, as shown in Table 1 above, the effects of improved bulk and excellent breaking length and smoothness can all be simultaneously manifested.

[0115] <Preparation Example: Preparation of Paper with Ultra-High Filler Content> Step 1As the pulp used to prepare ultra-high filler content paper, bleached softwood pulp and bleached hardwood pulp were mixed at a ratio of 5:5. After beating to achieve a freeness of 300 ml CSF (Canadian standard freeness), the papermaking filler prepared in Example 1 was mixed with the pulp at a weight ratio of 60:40, and this was referred to as "ultra-high filler content paper 1" pulp. Furthermore, the papermaking filler was mixed with the pulp at a weight ratio of 70:30, and this was referred to as "ultra-high filler content paper 2" pulp.

[0116] Step 2 Epoxy resin at a content of 5 wt% relative to the solids was added to each raw material of the "Ultra-high filler content paper 1" and "Ultra-high filler content paper 2" mixed in step 1, and paper with a basis weight of 60 g / m² was produced according to the paper test method (ISO 5269 / 1). The physical properties of the produced ultra-high filler content paper are shown in Table 3 and compared with those of Comparative Example 2. The filler content 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 in Table 3 as ash content. The ultra-high filler content paper with 50% or more filler added has significantly better bulk, breaking length, and smoothness than that of Comparative Example 2. Therefore, it is confirmed that the filler prepared in Example 1 can be used in the preparation and use of ultra-high filler content paper.

[0117] [Table 3] - Comparison of physical properties of ultra-high filler content paper

[0118] <Preparation Example 2: Preparation of Composite Materials> Step 1: To prepare sheets for use in the production of biocomposite materials, after beating bleached softwood pulp to a freeness of 300 ml CSF (Canadian standard freeness), it was mixed with the paper filler prepared in Example 1 at a weight ratio of 10:90 (beaten bleached softwood pulp: filler from Example 1), and epoxy resin at a relative solids content of 8 wt% was added to the paper stock to prepare paper samples with a basis weight of 80 g / m² according to paper testing method (ISO 5269 / 1).

[0119] Step 2: After melting PLA at 220°C to 240°C, curtain coating was applied to the paper prepared in Step 1 at a rate of 350 g / m² to prepare a "biocomposite material". For comparison, a sheet was prepared using only PLA at a rate of 430 g / m² without the paper sample, and this sheet was referred to as "biocomposite PLA". The nozzle temperature was maintained at 240°C. In the case of the paper sample, coating was performed at a temperature increased to 100°C, and a vacuum plate was applied to the side opposite to the coating side, and the vacuum was maintained at 0.6 atm to achieve effective internal penetration of PLA.

[0120] Step 3: After smoothing the surface of the paper sample where PLA has been fully penetrated using a roller, the bio-composite material is completed.

[0121] The weight and density of the prepared biocomposite material were measured at room temperature, the PLA content was calculated, and the calcium carbonate content was determined by measuring the weight after treatment at 525°C for 3 hours. Furthermore, the tensile strength was measured and is shown in Table 4.

[0122] [Table 4] -Physical properties of biocomposite materials

[0123] In Table 4, the tensile strength of the bio-composite PLA was not measurable due to its high brittleness. Instead, the elongation of the bio-composite was recorded as 2.3%, which represents the strain at the fracture point caused by tensile stress. Since the elongation of the bio-composite PLA was recorded as 0.0, it did not exhibit any tensile stress at all. The tensile strength of the bio-composite was recorded as 34.7 MPa, which is not significantly different from that of ordinary PLA composites.

[0124] <Preparation Example 3: Preparation of Stone Paper> Step 1 To prepare sheets for stone paper production, bleached softwood pulp was beaten to a freeness of 300 ml CSF (Canadian standard freeness), and then mixed with the papermaking filler prepared in Example 1 at a weight ratio of 10:90 (beaten bleached softwood pulp: filler from Example 1). Epoxy resin at a weight of 8 wt% relative to the solids content was added to the pulp, and paper samples with a basis weight of 80 g / m² were prepared according to paper testing method (ISO 5269 / 1).

[0125] Step 2: After melting high-density polyethylene (HDPE) with a density of 0.935 g / cm³ at 200°C to 220°C, apply it as a curtain coating on the paper prepared in Step 1 at a rate of 20 g / m². At this point, with the paper sample temperature raised to 100°C, apply a 0.6 atm vacuum plate to the side opposite the coating surface to achieve effective internal penetration of the HDPE.

[0126] Step 3: After smoothing the surface of the paper sample where HDPE has fully penetrated, the "stone paper" is completed.

[0127] The weight and density of the prepared stone paper were measured at room temperature, the HDPE content was calculated, and the calcium carbonate content was determined by weighing after treatment at 525°C for 1 hour. In addition, the tensile strength was measured and is shown in Table 5.

[0128] [Table 5] - Comparison of the physical properties of stone paper

[0129] Although embodiments of the present invention have been described above, the technical concept of the present invention is not limited to the embodiments presented in this specification. Those skilled in the art who understand the technical concept of the present invention will be able to easily propose other embodiments within the same technical concept by adding, changing, deleting, or adding constituent elements, and these embodiments will also fall within the technical concept of the present invention.

Claims

1. A method for preparing fillers for papermaking, characterized in that, The method includes the following steps: (1) Prepare a mixed aqueous solution, wherein the mixed aqueous solution contains an inorganic compound with an average size of 0.1 µm to 10 µm and a fibrous fibril with an average width of 5 nm to 10 µm in a weight ratio of 1:5 to 100, and the mixed aqueous solution has a solid content of 1 wt% to 60 wt%. (2) Adding an ionic polymer to the mixed aqueous solution and stirring to form a preflocculated material; and (3) To prepare the paper filler, 10 to 1000 parts by weight of calcium compound are added relative to 100 parts by weight of the inorganic compound contained in the mixed aqueous solution forming the preflocculate, and then carbon dioxide is injected at 10°C to 80°C until the pH is maintained at 7.0 ± 1.

0.

2. The method for preparing paper filling material according to claim 1, characterized in that, Step (1) includes: (1-1) A mixed solution with a solid content of 1 wt% to 60 wt% is prepared by mixing organic fibers with inorganic compounds at a weight ratio of 1:5 to 100, followed by the addition of water; and (1-2) The mixed aqueous solution is prepared by grinding the mixed solution, the mixed aqueous solution containing inorganic compounds with an average size of 0.1µm to 10µm and fibrous fibrils with an average width of 5nm to 10µm in a weight ratio of 1:5 to 100, and having a solid content of 1wt% to 60wt%.

3. The method for preparing paper filling material according to claim 1, characterized in that, The inorganic compound is selected from one or more of calcium carbonate, calcium oxide, calcium hydroxide, magnesium carbonate, gypsum, kaolin, calcined clay, talc, perlite, diatomaceous earth, zinc carbonate, lithium carbonate, magnesium hydroxide, and aluminum trihydrate.

4. The method for preparing paper filling material according to claim 3, characterized in that, The calcium carbonate is selected from one or more of heavy calcium carbonate and light calcium carbonate.

5. The method for preparing paper filling material according to claim 1, characterized in that, The fibrous fibrils include one or more selected from cellulose and chitin.

6. The method for preparing paper filling material according to claim 1, characterized in that, The ionic polymer is selected from one or more of anionic polymers and cationic polymers.

7. The method for preparing paper filling material according to claim 6, characterized in that, The anionic polymer is selected from one or more of polysaccharides, proteins, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives, epoxy acrylates, polyesters, polyurethanes, polyester acrylates, polyether acrylates, polyolefin dispersions, polyamides, vinyl copolymers, and polyacrylates.

8. The method for preparing paper filling material according to claim 6, characterized in that, The cationic polymer is selected from one or more of polyamide amine-epiohalo alcohol polymers, polyalkyl diallylamine-epiohalo alcohol polymers, polyethyleneimine, polyacrylamide, polyamine, polyethyleneamine, and cationic starch.

9. The method for preparing paper filling material according to claim 1, characterized in that, In step (2), the amount of one or more ionic polymers added is from 0.01 parts by weight to 10 parts by weight relative to 100 parts by weight of the mixed aqueous solution.

10. The method for preparing paper filling material according to claim 1, characterized in that, In step (3), the calcium compound is selected from one or more of calcium oxide, calcium hydroxide, calcium sulfate and calcium phosphate.

11. A filler for papermaking, characterized in that, The central region of the papermaking filler contains multiple fiber fibrils with an average width of 5 nm to 10 µm, and these fibrils are arranged in the shape of metal carbonates. The papermaking filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

12. A method for manufacturing paper, characterized in that, The method includes the following steps: (1) A mixture of 1 wt% to 60 wt% of the papermaking filler according to claim 11 and 40 wt% to 99 wt% of beaten natural or recycled pulp; and (2) Add the mixture from step (1) into a paper machine to produce paper.

13. A method for manufacturing paper with ultra-high filler content, characterized in that, The method includes the following steps: (1) Mixing 50 wt% to 99 wt% of the papermaking filler according to claim 11 with 1 wt% to 50 wt% of beaten natural pulp or recycled pulp, and adding 1 wt% to 30% of an ionomer for strength enhancement; and (2) The mixture from step (1) is added to a paper machine to manufacture the ultra-high filler content paper, wherein the inorganic material in the manufactured ultra-high filler content paper accounts for 50 wt% or more of its total weight.

14. A method for manufacturing composite materials, characterized in that, The method includes the following steps: (1) Mixing 50 wt% to 99 wt% of the papermaking filler according to claim 11 with 1 wt% to 40 wt% of beaten natural pulp or recycled pulp; and (2) The mixture from step (1) is added to a paper machine to produce sheets of paper; and (3) After step (2), the composite material is manufactured by coating or impregnating 50 to 5000 parts by weight of a synthetic polymer or a biodegradable polymer relative to 100 parts by weight of the manufactured sheet.

15. A method for manufacturing stone paper, characterized in that, The method includes the following steps: (1) Mixing 50 wt% to 99 wt% of the papermaking filler according to claim 11 with 1 wt% to 50 wt% of beaten natural pulp or recycled pulp; (2) The mixture from step (1) is added to a paper machine to produce sheets in the form of paper; and (3) After step (2), the stone paper is manufactured by coating or impregnating it with a synthetic polymer or a biodegradable polymer in a ratio of 1 to 50 parts by weight relative to 100 parts by weight of the manufactured sheet.

16. A type of paper, characterized in that, The paper is formed by including a filler, wherein the central region of the filler contains multiple fibrous fibrils with an average width of 5 nm to 10 µm, and the fibrils are shaped as metal carbonates disposed on the fibrous fibrils. The filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

17. A paper with ultra-high filler content, characterized in that, The ultra-high filler content paper is formed by including filler, wherein the central region of the filler contains multiple fibrous fibrils with an average width of 5 nm to 10 µm, and these fibrils are shaped as metal carbonates disposed on the fibrous fibrils. The filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate. Inorganic materials account for 50 wt% or more of the total weight of the paper.

18. A composite material, characterized in that, The composite material is formed by including a filler, wherein the central region of the filler contains multiple fibrous fibrils with an average width of 5 nm to 10 µm, and the fibrils are shaped as metal carbonates disposed on the fibrous fibrils. The filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

19. A type of stone paper, characterized in that, The stone paper is formed by including a filler, wherein the central region of the filler contains multiple fibrous fibrils with an average width of 5 nm to 10 µm, and the fibrils are shaped as metal carbonates disposed on the fibrous fibrils. The filler comprises 1 vol% to 20 vol% of the fiber fibrils and 80 vol% to 99 vol% of the metal carbonate.

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