Wet wipe with sterilizing power, and method for manufacturing same

Abstract

The present invention relates to a wet wipe with sterilizing power, which uses an eco-friendly material, and a method for manufacturing same. The method for manufacturing the wet wipe with sterilizing power, according to one embodiment of the present invention, comprises the steps of: a) providing pulp; b) preparing an impregnation liquid to be impregnated into the pulp; and c) impregnating the pulp with the impregnation liquid, thereby manufacturing a wet wipe, wherein the impregnation liquid can include a photocatalyst, a natural preservative and purified water.

Description

Wet tissue with sterilizing power and method for manufacturing the same

[0001] The present invention relates to a wet tissue having a sterilizing effect and a method for manufacturing the same, and more specifically, to provide a wet tissue having a sterilizing effect and a method for manufacturing the same, which is biodegradable, harmless to the human body, and is made by impregnating environmentally friendly pulp with a photocatalyst having a sterilizing effect by photoactivity and a natural preservative of natural origin.

[0002] Wet tissues are moistened tissues that can be used to wipe the user's hands and face regardless of location. Recently, they have also been widely used to wipe the skin of infants and toddlers when changing diapers or for cleaning purposes.

[0003] Because wet wipes are soaked in liquid, even if they are sterilized during the manufacturing process, they are susceptible to the growth of bacteria and mold when exposed to air. Therefore, disinfectants are added to wet wipes. Because of this, wet wipes have been the subject of constant controversy over their chemical composition. In 2014, an article reporting that some wet wipes contained the toxic substance "cetrimonium bromide" led to a large-scale product return crisis. In 2016, an article reporting that wet wipes containing humidifier disinfectant ingredients were on the market sparked another debate over the harmful effects of wet wipes. Consequently, interest in natural antibacterial substances, particularly plant extracts with proven biosafety and antibacterial activity, is growing.

[0004] Furthermore, with environmental issues emerging as a global social issue, microplastics derived from synthetic fibers are particularly a hot topic. Concerns are growing over the fact that wet wipes, made mostly of polyester fibers, are not recyclable and must be disposed of through incineration or landfill.

[0005] Accordingly, interest in the fiber materials and antibacterial additives of wet tissues, the use of which is rapidly increasing every year, is increasing, and research on safer and more environmentally friendly wet tissues is needed.

[0006] [Prior Art Literature]

[0007] [Patent Document]

[0008] (Patent Document 0001) Republic of Korea Patent Publication No. 10-1555341

[0009] Despite environmental concerns, the wet tissue market continues to grow rapidly, and the risks posed by microorganisms like viruses and bacteria have exploded since the COVID-19 pandemic. Furthermore, due to increased concerns about personal hygiene, including fine dust and the spread of COVID-19, the wet tissue market is expected to grow by over 30% annually as of 2021. Despite the expansion of the wet tissue market, environmental issues and controversies surrounding its harmful effects on the human body persist. These include environmental concerns related to microplastics and waste generated from plastic materials, and the potential harm to the human body caused by preservatives. To address these environmental and human health concerns, we plan to develop a wet tissue using a less harmful photocatalyst.

[0010] Accordingly, the problem to be solved by the present invention is to provide a wet tissue and a method for manufacturing the same, which is biodegradable, harmless to the human body, and has a sterilizing effect, by impregnating environmentally friendly pulp with a photocatalyst having a sterilizing effect by photoactivity and a natural preservative of natural origin.

[0011] Other objects and advantages of the present invention will become more apparent from the detailed description, claims and drawings below.

[0012] A method for manufacturing a wet tissue having a sterilizing power according to one embodiment of the present invention for achieving the above-described problem comprises the steps of: a) providing pulp; b) preparing an impregnation liquid to be impregnated into the pulp; and c) manufacturing a wet tissue by impregnating the pulp with the impregnation liquid, wherein the impregnation liquid may include a photocatalyst, a natural preservative, and purified water.

[0013] A method for manufacturing a wet tissue having a sterilizing power according to an exemplary embodiment of the present invention can form an embossing having a plurality of concave and convex shapes on the surface of the pulp in step a).

[0014] A method for manufacturing a wet tissue having a sterilizing power according to an exemplary embodiment of the present invention is such that the photocatalyst of the impregnating liquid is a metal oxide or titanium dioxide combined with a metal catalyst.

[0015] A method for manufacturing a wet tissue having a sterilizing power according to an exemplary embodiment of the present invention is characterized in that the metal oxide may include any one metal element selected from the group consisting of W, Mo, Cr, Re, Ir, Ta, Hf, Fe, Ni, Cu, Zn, Mn, Y, Zr, Sn, V, Bi, Sr, Ca, Nb, K, Na, Li, and combinations thereof.

[0016] A method for manufacturing a wet tissue having a sterilizing power according to an exemplary embodiment of the present invention is characterized in that the metal catalyst is one selected from the group consisting of Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, and combinations thereof.

[0017] A method for manufacturing a wet tissue having a sterilizing power according to an exemplary embodiment of the present invention is characterized in that the natural preservative of the impregnating liquid is a plant extract selected from the group consisting of lavender, grapefruit, green tea, lemongrass, tea tree, manuka, eucalyptus, rosemary, lime, lemon, and peppermint.

[0018] According to another embodiment of the present invention for achieving the above-mentioned problem, a wet tissue may include an impregnating liquid containing a photocatalyst, a natural preservative, and purified water, and pulp impregnated with the impregnating liquid.

[0019] A wet tissue having a sterilizing power according to an exemplary embodiment of the present invention is a wet tissue in which the photocatalyst of the impregnating liquid is a metal oxide or titanium dioxide combined with a metal catalyst.

[0020] A wet tissue having a sterilizing power according to an exemplary embodiment of the present invention may include a metal oxide selected from the group consisting of W, Mo, Cr, Re, Ir, Ta, Hf, Fe, Ni, Cu, Zn, Mn, Y, Zr, Sn, V, Bi, Sr, Ca, Nb, K, Na, Li, and combinations thereof.

[0021] A wet tissue having a sterilizing power according to an exemplary embodiment of the present invention, wherein the metal catalyst is any one selected from the group consisting of Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, and combinations thereof.

[0022] A wet tissue having a sterilizing power according to an exemplary embodiment of the present invention, wherein the titanium dioxide combined with the metal catalyst has a sterilizing effect against methicillin-resistant Staphylococcus aureus or Escherichia coli.

[0023] According to the present invention, a wet tissue and a method for manufacturing the same can be provided, which are biodegradable, harmless to the human body, and have a sterilizing effect by impregnating environmentally friendly pulp with a photocatalyst having a sterilizing effect by photoactivity and a natural preservative of natural origin.

[0024] Figure 1 is a flowchart showing a method for manufacturing a wet tissue according to an embodiment of the present invention.

[0025] Figure 2 shows the results of an experiment on the sterilizing effect of a wet tissue manufactured according to an embodiment of the present invention.

[0026] Figure 3 shows the sterilizing effect of a photocatalyst included in a wet tissue manufactured according to an embodiment of the present invention on E. coli.

[0027] Figure 4 shows the sterilizing effect of a photocatalyst included in a wet tissue manufactured according to an embodiment of the present invention against methicillin-resistant Staphylococcus aureus (MRSA).

[0028] Figure 5 shows the results of a chemical safety test of a photocatalyst included in a wet tissue manufactured according to an embodiment of the present invention.

[0029] The advantages and features of the present invention, and the methods for achieving them, will become clear with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Specific details for implementing the present invention will be described in detail with reference to the attached drawings. Regardless of the drawings, the same reference numerals refer to the same components, and "and / or" includes each and all combinations of one or more of the mentioned items.

[0030] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms, unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0031] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those of ordinary skill in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0032] Hereinafter, a wet tissue having a sterilizing power and a method for manufacturing the same according to an embodiment of the present invention will be described.

[0033] FIG. 1 is a flowchart showing a method for manufacturing a wet tissue according to an embodiment of the present invention, FIG. 2 shows the results of an experiment on the sterilizing effect of a wet tissue manufactured according to an embodiment of the present invention, FIG. 3 shows the sterilizing effect of a photocatalyst included in a wet tissue manufactured according to an embodiment of the present invention against E. coli, FIG. 4 shows the sterilizing effect of a photocatalyst included in a wet tissue manufactured according to an embodiment of the present invention against methicillin-resistant Staphylococcus aureus (MRSA), and FIG. 5 shows the results of a chemical safety test of a photocatalyst included in a wet tissue manufactured according to an embodiment of the present invention.

[0034] Referring to FIG. 1, a method for manufacturing a wet tissue having a sterilizing power according to an embodiment of the present invention includes a) a step of providing pulp (S10), b) a step of preparing an impregnating solution to be impregnated into the pulp (S20), and c) a step of manufacturing a wet tissue by impregnating the pulp into the impregnating solution (S30), wherein the impregnating solution may include a photocatalyst, a natural preservative, and purified water.

[0035] First, in order to manufacture wet tissues, pulp, which can be considered the main body of the wet tissue, is provided (S10).

[0036] Here, natural pulp can be used as the pulp for the wet tissue fabric, or environmentally friendly recycled waste materials can also be used. Recyclable materials that can be used as the wet tissue pulp of the present invention include waste toilet paper, waste shredded pulp, waste cotton pulp, waste wood pulp, and waste recycled pulp. Natural pulp is preferably used as the pulp. Unless otherwise specified, the pulp used in the present invention is assumed to be natural pulp. Natural pulp has the advantage of being biodegradable and easy to recycle. Coniferous trees can be used as the raw material for natural pulp.

[0037] The pulp can be cut into appropriate sizes for manufacturing wet tissues. Furthermore, the pulp weight can be selected from a range of 40GSM (Gram Per Square Meter) to 75GSM, depending on the intended use of the wet tissue and the needs of the consumer.

[0038] If the pulp weight is less than 40 GSM, the tensile strength and wet strength may decrease rapidly, which may deteriorate the physical properties of wet tissues manufactured with the pulp. In other words, when wet tissues are used, they may be weak and flimsy for the user to handle and may not have satisfactory strength.

[0039] When the pulp weight exceeds 75 GSM, tensile strength and wet strength increase dramatically, potentially reducing processability when manufacturing wet tissues. Furthermore, wet tissues can be stiff and uncomfortable for users.

[0040] Meanwhile, in step a), an additional step of forming an embossing having a plurality of concave and convex impressions on the surface of the pulp may be performed. The embossing may be formed by introducing the prepared pulp into an embossing roller and pressing it.

[0041] More specifically, the prepared pulp is fed into an embossing roller. At this time, the embossing roller is driven to rotate so that, for example, the leading edge of a single layer of pulp is pressed, thereby forming an embossing having a plurality of concave and convex impressions with a depth of 0.5 to 1.0 mm on the surface of the pulp.

[0042] Embossing rollers are provided as a pair, arranged vertically, one having protruding projections and the other having recessed portions corresponding to the shape of the protruding projections, and are rotated while interlocked with each other. As the protruding projections are accommodated in the recessed portions, embossing is formed in the pulp. In this case, the embossing rollers can form embossing at a temperature of 200°C to 300°C. Pulp with embossing formed by the above method can be prepared and provided.

[0043] Next, an impregnating liquid to be impregnated into the pulp is prepared (S20).

[0044] The impregnating agent is intended to provide moisture and functionality to the pulp, and may include purified water and a functional material. The impregnating agent used in the method for manufacturing wet tissues according to an embodiment of the present invention may include a photocatalyst, a natural preservative, and purified water.

[0045] Here, the photocatalyst can impart antibacterial and sterilizing properties to the wet tissues being manufactured. The photocatalyst can generate active oxygen when exposed to light, and these active oxygen molecules can provide antibacterial and sterilizing properties.

[0046] The wet tissue according to an embodiment of the present invention may have antibacterial and sterilizing properties through a photocatalyst that is relatively harmless to the human body, rather than having antibacterial and sterilizing properties through existing chemical substances (typically chlorine compounds).

[0047] Here, the photocatalyst may be a metal oxide or titanium dioxide combined with a metal catalyst.

[0048] The metal oxide may include any one metal element selected from the group consisting of W, Mo, Cr, Re, Ir, Ta, Hf, Fe, Ni, Cu, Zn, Mn, Y, Zr, Sn, V, Bi, Sr, Ca, Nb, K, Na, Li, and combinations thereof. When the metal oxide is exposed to light, electrons are excited to a conduction band higher than the band gap, and active oxygen may be generated on the surface of the metal oxide. Accordingly, the wet tissue according to an embodiment of the present invention may have a sterilizing effect and an antibacterial effect.

[0049] Meanwhile, the photocatalyst of the impregnating solution may be titanium dioxide combined with a metal catalyst, in addition to a metal oxide.

[0050] Titanium dioxide combined with the above metal catalyst can be manufactured as follows.

[0051] That is, a) preparing a raw material-titanium dioxide in which anatase phase and rutile phase are mixed, b) producing titanium dioxide by roasting the raw material-titanium dioxide, c) forming a mixed solution by mixing the titanium dioxide, solvent, and metal catalyst, and then hydrothermally synthesizing the mixed solution to produce a catalyst complex, d) washing the catalyst complex, centrifuging the washing treatment solution containing the catalyst complex to obtain the washed catalyst complex, and e) drying the obtained catalyst complex. Here, drying can be performed by freeze-drying.

[0052] Titanium dioxide combined with a metal catalyst, which is a photocatalyst having a sterilizing power according to an embodiment of the present invention, excites electrons in the conduction band of visible light to the valence band, and the generated charge pairs move to the interface to cause electron transfer, and generate active oxygen such as OH radicals on the surface, which can have the effect of killing and sterilizing microorganisms.

[0053] Conventional titanium dioxide has a short duration of photoactive effect due to rapid recombination of electron-hole pairs, but titanium dioxide combined with a metal catalyst according to an embodiment of the present invention can increase the duration of photoactive effect by delaying the time for excited electrons to recombine because the metal catalyst in the material acts as an electron sink.

[0054] Here, the metal catalyst of the titanium dioxide combined with the metal catalyst, which is a photocatalyst according to an embodiment of the present invention, may be any one selected from the group consisting of Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, and combinations thereof.

[0055] The impregnating solution may contain natural preservatives. These preservatives may be included to prevent deterioration and quality deterioration of the wet wipes. Furthermore, the fragrance contained in the natural preservatives can impart a subtle fragrance to the wet wipes, providing a refreshing feeling to users when using them.

[0056] The natural preservative can be any one selected from the group consisting of lavender, grapefruit, green tea, lemongrass, tea tree, manuka, eucalyptus, rosemary, lime, lemon, and peppermint. Here, grapefruit extract has a bactericidal effect, thyme has an antibacterial effect, lemongrass has antibacterial and antiseptic effects, tea tree has antibacterial and antibacterial effects, chamomile has anti-inflammatory and antiseptic effects, manuka has an antibacterial effect, eucalyptus has an antibacterial effect, stevia has antioxidant, bactericidal, and antiseptic effects, rosemary has bactericidal, antibacterial, and antioxidant effects, lavender has bactericidal, anti-inflammatory, and antiseptic effects, peppermint has bactericidal, anti-inflammatory, and antiseptic effects, vitamin tree has antioxidant and antibacterial effects, lime has an antibacterial effect, and lemon has an antibacterial effect.

[0057] Sterilized primary to secondary distilled water can be used as purified water.

[0058] Meanwhile, for 100 wt% of the impregnating liquid, it may contain 40 wt% to 60 wt% of a photocatalyst, 5 wt% to 10 wt% of a natural preservative, and the remainder of purified water. If the content of the photocatalyst is less than 40 wt%, the sterilizing power of the wet tissue may be reduced. If the content of the photocatalyst exceeds 60 wt%, the sterilizing power is enhanced, but the content of purified water becomes relatively small, so the amount of moisture supplied to the wet tissue may be reduced. If the content of the natural preservative is less than 5 wt%, the preservative, sterilization, and antibacterial effects of the wet tissue may be reduced. If the content of the natural preservative exceeds 10 wt%, the content of the photocatalyst becomes relatively small, so the sterilizing and antibacterial power of the wet tissue may be reduced.

[0059] Next, the pulp is impregnated with the prepared impregnating solution to manufacture a wet tissue (S30).

[0060] The pulp prepared in step a) is impregnated with the impregnating solution prepared in step b) to complete the manufacture of wet tissues. After the pulp is sufficiently impregnated with the impregnating solution, it is lifted out and the current step is performed. Impregnation can be performed for approximately 1 to 20 minutes, and the impregnation time can be adjusted depending on the basis weight of the pulp. Impregnation can be performed at room temperature.

[0061] The wet tissue according to an embodiment of the present invention is a wet tissue containing natural pulp that does not contain microplastics and is biodegradable, making it an environmentally friendly material.

[0062] Most commercially available natural pulp wet tissues are made of rayon, but the rayon manufacturing process itself can cause environmental pollution, which can be a fatal drawback. A wet tissue according to an embodiment of the present invention is a wet tissue material made of 100% natural paper pulp. Furthermore, it contains a natural preservative that is less harmful to the human body and has long-lasting sterilization properties. Therefore, even if a source of contamination is exposed after opening the wet tissue, it can self-sterilize, eliminating concerns about potential harm to the human body. Furthermore, a wet tissue according to an embodiment of the present invention may include a photocatalyst that can sterilize and disinfect even under sunlight or fluorescent light.

[0063] Hereinafter, the present invention will be described in more detail through examples and experimental examples. These examples and experimental examples are intended solely to illustrate the present invention more specifically. It will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples and experimental examples, in accordance with the gist of the present invention.

[0064] Example 1: Preparation of a photocatalyst (titanium dioxide combined with a metal catalyst) included in wet tissues

[0065] 10g of raw material-titanium dioxide was prepared by mixing 8.5g of anatase phase and 1.5g of rutile phase. The prepared raw material-titanium dioxide was washed with 1L of triple-distilled water, and then filtered using a filter paper to wash and filter the raw material-titanium dioxide. The washed raw material-titanium dioxide was roasted in a temperature atmosphere of 500℃.

[0066] Titanium dioxide was prepared by calcining raw material - titanium dioxide. A mixed solution was prepared by mixing 5 g of the prepared titanium dioxide, 0.21 g of zinc powder as a cocatalyst, and 0.005 g of ethanol as a solvent. The prepared mixed solution was subjected to hydrothermal synthesis in an atmosphere at a temperature of 150°C for 5 hours, thereby preparing 4.5 g of a catalyst complex. After washing 4.5 g of the catalyst complex with 500 ml of sterilized, triple-distilled water, the washing solution was centrifuged in a centrifuge at a speed of 3,000 rpm for 15 minutes to obtain a washed catalyst complex.

[0067] Afterwards, 4.3 g of the catalyst complex was freeze-dried at -80°C for 24 hours to finally manufacture a photocatalyst according to the present invention.

[0068] Example 2: Preparation of wet tissues

[0069] Natural pulp was prepared using coniferous wood cut to a size of 0.5 m wide and 0.5 m long. The basis weight of the natural pulp was 50 gsm.

[0070] Meanwhile, 50 g of the photocatalyst (zinc-titanium dioxide combined catalyst) manufactured in Example 1, 7 g of lavender as a natural preservative, and 43 g of purified water as a solvent were prepared, mixed, and stirred for 1 hour to prepare an impregnation solution. The stirring was performed at room temperature.

[0071] After impregnating the prepared natural pulp in the prepared impregnation solution for 10 minutes, wet tissues were finally manufactured.

[0072] Experimental Example 1: Sterilizing Effect of Wet Tissues

[0073] Escherichia coli (E. coli, KCTC 2571) as a strain 10 7After disinfection using the wet tissue manufactured in Example 2 on a cultured specimen containing cfu / mL, visible light (Fig. 2A) and ultraviolet light (Fig. 2B) were irradiated. As a result, it was observed that the above strains were sterilized in the specimens disinfected with the wet tissue manufactured in Example 2 and irradiated with light (visible light / ultraviolet light). The results are shown in Fig. 2.

[0074] Experimental Example 2: Sterilization effect of the photocatalyst of Example 1 against E. coli

[0075] Referring to FIG. 3, it was confirmed that when disinfected with the photocatalyst of Example 1 included in the wet tissue of the present invention, the indicator bacteria, E. coli, were sterilized by 99.999%. Accordingly, it was confirmed that the wet tissue according to the example of the present invention to which the photocatalyst of Example 1 was applied had a sterilizing effect against E. coli.

[0076] Experimental Example 3: Sterilization effect of the photocatalyst of Example 1 against methicillin-resistant Staphylococcus aureus (MRSA)

[0077] The antibacterial effect against methicillin-resistant Staphylococcus aureus (MRSA) was measured.

[0078] The strain used was MRSA (Staphylococcus aureus subsp. Aureus) ATCC 33591. The concentration of the inoculum (CFU / mL) was 7.2*10 5 (MRSA) and the inoculation volume was 150㎕.

[0079] The test environment was conducted at a temperature of 36.0°C to 38.0°C, and the experiment was conducted on test specimens that were injected with a photocatalyst and control specimens that were not injected. The test and control specimens were irradiated with UV light at an intensity of 0.25 mW / cm2. The results are shown in Table 1 and Figure 4 below.

[0080] Test item Test method Test result Initial concentration (CFU / mL) Concentration after 4 hours of exposure (CFU / mL) After UV irradiation After dark storage Antibacterial test: MRSA Control KS L ISO 27447: 20093.5*10 5 2.7*105 2.9*10 5 Test piece 3.5*10 5 <102.1*10 5

[0081] Referring to Table 1 and Figure 4, it was found that the photocatalyst of the present invention has an excellent sterilizing effect due to photoactivity.

[0082] Experimental Example 4: Safety Experiment

[0083] The photocatalyst of Example 1 was subjected to chemical safety testing by the Korea Testing & Research Institute for Chemical Industry. The results are shown in Figure 5. As a result of the safety testing, the photocatalyst of Example 1 was deemed safe. Therefore, it was confirmed that the photocatalyst of Example 1 is chemically safe even when applied to daily necessities. Therefore, wet tissues according to the present invention containing the photocatalyst may not cause any harmful effects due to the photocatalyst.

[0084] While the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but can be manufactured in various different forms. Those skilled in the art will understand that the present invention can be implemented in other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood to be illustrative in all respects and not restrictive.

Claims

1. a) Step of providing pulp; b) a step of preparing an impregnating liquid to be impregnated into the pulp; and c) a step of manufacturing a wet tissue by impregnating the pulp with the impregnating liquid, The above impregnation liquid is a method for manufacturing a wet tissue having a sterilizing power, which contains a photocatalyst, a natural preservative, and purified water.

2. In paragraph 1, A method for manufacturing a wet tissue having sterilizing power, further comprising, in step a), forming an embossing having a plurality of concave and convex shapes on the surface of the pulp.

3. In paragraph 1, A method for manufacturing a wet tissue having a sterilizing power, characterized in that the photocatalyst of the impregnating liquid is titanium dioxide combined with a metal oxide or a metal catalyst.

4. In paragraph 3, A method for manufacturing a wet tissue having a sterilizing power, characterized in that the metal oxide comprises any one metal element selected from the group consisting of W, Mo, Cr, Re, Ir, Ta, Hf, Fe, Ni, Cu, Zn, Mn, Y, Zr, Sn, V, Bi, Sr, Ca, Nb, K, Na, Li, and combinations thereof.

5. In paragraph 3, A method for manufacturing a wet tissue having a sterilizing power, wherein the metal catalyst is any one selected from the group consisting of Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, and combinations thereof.

6. In paragraph 1, A method for manufacturing a wet tissue having a sterilizing power, characterized in that the natural preservative of the impregnating liquid is a plant extract selected from the group consisting of lavender, grapefruit, green tea, lemongrass, tea tree, manuka, eucalyptus, rosemary, lime, lemon, and peppermint.

7. A wet tissue having sterilizing power manufactured by the manufacturing method of paragraph 1.

8. Impregnation solution containing photocatalyst, natural preservative and purified water; and A wet tissue having a sterilizing power, comprising pulp impregnated with the above impregnating liquid.

9. In paragraph 8, A wet tissue having a sterilizing power, characterized in that the photocatalyst of the impregnating liquid is titanium dioxide combined with a metal oxide or a metal catalyst.

10. In paragraph 9, A wet tissue having a sterilizing power, characterized in that the metal oxide comprises any one metal element selected from the group consisting of W, Mo, Cr, Re, Ir, Ta, Hf, Fe, Ni, Cu, Zn, Mn, Y, Zr, Sn, V, Bi, Sr, Ca, Nb, K, Na, Li, and combinations thereof.

11. In paragraph 9, A wet tissue having a sterilizing power, wherein the metal catalyst is any one selected from the group consisting of Ag, Au, Pt, Ru, Ir, Os, Rh, Pd, W, Mo, Cr, Re, Zn, Mn, Y, Zr, Ni, Cu, Fe, and combinations thereof.

12. In paragraph 9, A wet tissue having a sterilizing power, characterized in that the titanium dioxide combined with the above metal catalyst has a sterilizing effect against methicillin-resistant Staphylococcus aureus or Escherichia coli.

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