Stainless steel composite panel with polyethylene sheet having antibacterial and antifungal properties

Abstract

The present invention relates to a stainless steel composite panel formed on a substrate layer of a structure, characterized by comprising: a plate-shaped plate of a certain thickness made of stainless steel material; an adhesive film; and a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties. The above-described polyethylene sheet is a sheet with excellent antibacterial properties and improved mechanical properties such as surface hardness and tensile strength, configured to suppress surface damage and deformation of the stainless steel panel caused by the external environment. Accordingly, the durability and structural stability of the stainless steel panel are improved, and hygiene and maintenance efficiency in humid environments are enhanced. The present invention can be applied to various structures, including steel structures as well as concrete structures such as water tanks and storage tanks, thereby contributing to the extension of the lifespan of the structures.

Description

Technology Field

[0001] The present invention relates to a stainless steel composite panel comprising a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties. Background Technology

[0002] Concrete structures are installed on building rooftops, underground spaces, and ground levels to accommodate and regulate various equipment, water, or storage media, and are also widely utilized as auxiliary structures for industrial and commercial facilities. When these concrete structures are exposed to moisture, humidity, and chemical environments for extended periods, there is a risk of cracking, spalling, and delamination due to corrosion of internal reinforcing steel, which can simultaneously compromise structural stability and hygiene. Accordingly, reinforcing the concrete surface with stainless steel panels is generally adopted as a measure to ensure the durability and hygiene of the structures.

[0003] Stainless steel panels serve as a protective layer for concrete structures based on their excellent corrosion resistance and mechanical strength. However, when directly exposed to the external environment, surface scratching, local deformation, or deterioration of joints may occur due to temperature changes, humid environments, repetitive cleaning operations, and continuous loading. In particular, when stainless steel panels exceeding a certain area are applied with a relatively thin thickness, bending deformation is likely to occur due to local or long-term loads, potentially reducing the structural stability and lifespan of the panels.

[0004] In addition, the surface of stainless steel panels may become contaminated or susceptible to the proliferation of microorganisms such as bacteria and mold in environments where wet conditions are repeated. This increases the burden of maintenance in storage facilities or spaces requiring hygiene. Therefore, there is a need for an additional protective layer that can protect the panels from external impacts, friction, and environmental factors while maintaining the original structural functions of the stainless steel panels, and simultaneously improve hygiene and durability during long-term use.

[0005] Polyethylene sheets are lightweight and possess excellent water and chemical resistance, allowing them to maintain stable physical properties even in humid environments. Furthermore, through a laminated structure with stainless steel panels, they can function as a protective layer that disperses external loads and impacts to suppress deformation of the panels. In particular, if the polyethylene sheets achieve a certain level of hardness, their resistance to scratches, indentations, and repeated loading is enhanced, which can effectively reduce surface damage and long-term deformation of the stainless steel panels.

[0006] In addition, if the polyethylene sheet possesses antibacterial and antifungal properties, it can continuously maintain surface hygiene by inhibiting the growth of bacteria and mold that are prone to occurring in humid environments, and it can also contribute to shortening cleaning cycles and reducing maintenance costs. Therefore, polyethylene sheets attached to stainless steel panels are required to go beyond a simple protective film and serve as a functional protective layer that comprehensively improves structural stability, durability, and hygiene by simultaneously satisfying sufficient hardness and antibacterial and antifungal properties.

[0007] Korean Registered Patent Publication No. 10-1713499 is cited as a similar prior art document regarding this. Prior art literature

[0008] Korean Patent Publication No. 10-1713499 (Publication Date: Feb. 28, 2017) The problem to be solved

[0009] The objective of the present invention is to provide a stainless steel composite panel comprising a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties.

[0010] The present invention aims to apply to the surface of a stainless steel panel reinforcing a concrete structure to suppress damage and deformation of the panel surface and improve long-term durability. It also aims to improve the hygiene of the stainless steel composite panel by suppressing contamination and microbial growth that may occur in a humid environment. Furthermore, it aims to simultaneously secure structural stability and maintenance efficiency of the stainless steel panel by applying a polyethylene sheet with improved mechanical properties, such as surface hardness and tensile strength, as a protective layer. means of solving the problem

[0011] The present invention relates to a stainless steel panel formed on a substrate layer of a structure, wherein

[0012] Plate-shaped plate of a certain thickness made of stainless steel;

[0013] Adhesive film; and

[0014] The present invention relates to a stainless steel composite panel characterized by including a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties. The polyethylene sheet is a sheet having antibacterial properties and improved mechanical properties such as surface hardness and tensile strength, and is characterized by being able to suppress surface damage and deformation of the stainless steel panel caused by the external environment, improving the durability and structural stability of the stainless steel panel, and having an effect on hygiene and maintenance efficiency in a humid environment.

[0015] The above stainless steel composite panel may have the plate-shaped plate installed on the substrate layer of the structure, the adhesive film laminated on the substrate layer of the structure, and the polyethylene sheet laminated on the adhesive film.

[0016] The above polyethylene sheet may comprise polyethylene resin; polyolefin elastomer; and antibacterial-antifungal agent.

[0017] The above polyethylene resin may be linear low-density polyethylene.

[0018] The above polyolefin elastomer may have a melt index of 4.30 to 5.70 g / 10 min and a density of 0.868 to 0.873 g / cm³.

[0019] The above antibacterial-antifungal agent may be modified sulfur.

[0020] The above organic-inorganic reinforcing agent may include nanocellulose, titanium dioxide, and a modified compatibilizer.

[0021] The above-mentioned modified compatibilizer may be a polyolefin-based modified resin containing polar functional groups.

[0022] The substrate layer of the above structure may be concrete or steel. Effects of the invention

[0023] The present invention relates to a stainless steel composite panel comprising a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties. By applying a polyethylene sheet with improved antibacterial properties and mechanical properties as a protective layer to the outer surface of a stainless steel panel reinforcing a concrete structure, damage and deformation of the stainless steel panel surface caused by the external environment can be effectively suppressed. Accordingly, bending deformation, surface deterioration, and joint damage of the stainless steel panel are reduced, thereby improving the long-term durability and stability of the structure.

[0024] In addition, the antibacterial properties of the polyethylene sheet inhibit the adhesion of contaminants and the growth of microorganisms that may occur in humid environments, thereby effectively improving the hygiene of structures requiring hygienic management, such as water tanks or storage tanks. As a result, the cleaning and maintenance cycle is extended, and cost savings can also be expected.

[0025] In addition, polyethylene sheets with improved mechanical properties, such as surface strength and tensile strength, protect the stainless steel panels, thereby mitigating panel deformation caused by local or repetitive loads and supplementing structural rigidity. As a result, it is possible to extend the overall lifespan of the laminated structure composed of concrete structures and stainless steel composite panels and improve maintenance efficiency. Specific details for implementing the invention

[0026] A stainless steel composite panel containing a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties according to the present invention will be described in detail below. The drawings presented below are provided as examples to ensure that the concept of the present invention is sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the concept of the present invention. Unless otherwise defined, technical and scientific terms used herewith have the meaning commonly understood by those skilled in the art to which this invention pertains, and descriptions of known functions and configurations that could unnecessarily obscure the essence of the present invention are omitted in the following description and accompanying drawings.

[0027] One aspect of the present invention relates to a stainless steel composite panel formed on a substrate layer of a structure, characterized by comprising: a plate-shaped plate of a certain thickness made of stainless steel material; an adhesive film; and a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties.

[0028] The above stainless steel composite panel may have the plate-shaped plate installed on the substrate layer of the structure, the adhesive film laminated on the substrate layer of the structure, and the polyethylene sheet laminated on the adhesive film.

[0029] The above-described polyethylene sheet is an antibacterial sheet with improved mechanical properties, such as surface hardness and tensile strength, configured to suppress surface damage and deformation of the stainless steel panel caused by the external environment. Accordingly, the wear resistance, scratch resistance, durability, and structural stability of the stainless steel panel are improved, and hygiene and maintenance efficiency in humid environments are enhanced. The present invention can be applied to various structures, including steel structures as well as concrete structures such as water tanks and storage tanks, thereby contributing to the extension of the lifespan of the structures.

[0030] The following describes each component of a polyethylene sheet according to an example of the present invention in more detail.

[0031] The above polyethylene sheet may comprise polyethylene resin; polyolefin elastomer; and antibacterial-antifungal agents and organic-inorganic reinforcing agents.

[0032] As the base resin for the polyethylene sheet, low-density polyethylene (LDPE) may be used, and more preferably, linear low-density polyethylene (LLDPE) with a melt index of 1.9 to 2.1 g / 10 min (2.16 kg) and a density of 0.915 to 0.925 g / cm³ (23°C) is used to impart flexibility and tear performance to the sheet. Linear low-density polyethylene having the above properties has superior tensile strength compared to general low-density polyethylene and is characterized by excellent toughness, heat resistance, and cold resistance. Therefore, a polyethylene sheet containing the above polyethylene resin can have excellent resistance to environmental stress cracking.

[0033] The above polyolefin elastomer is intended to impart impact resistance, heat resistance, and cold resistance to polyethylene sheets, and specifically may be an ethylene-1-octene copolymer. The above ethylene-1-octene copolymer has a glass transition temperature (Tg) in the range of -80 to -55 ℃, and by combining ethylene with relatively long octene chains, the degree of crystallinity is lowered and the flexibility of the polymer chains is increased, thereby imparting rubber-like flexibility and impact resistance even at low temperatures. The above ethylene-1-octene copolymer has a melt index of 4.30 to 5.70 g / 10 min (2.16 kg) and a density of 0.868 to 0.873 g / cm³ (23 ℃). Since it has a lower density than general polyethylene, it can be used to manufacture lightweight sheets. It also has high flexibility and impact strength even in low-temperature environments, and has a high self-elongation rate, so when contained in polyethylene sheets, it has the effect of improving elongation.

[0034] The polyolefin elastomer may be included in an amount of 80 to 120 parts by weight relative to 100 parts by weight of the polyethylene resin. If the amount is less than 80 parts by weight, a problem with low elongation may occur, and if the amount exceeds 120 parts by weight, the basic mechanical properties as a sheet may be impaired, such as tensile strength being impaired.

[0035] The above antimicrobial-antifungal agent and organic-inorganic reinforcing agent are intended to enhance antimicrobial-antifungal properties and mechanical performance, and may first be included in a masterbatch, after which the masterbatch is included in a polyethylene sheet composition. Specifically, the masterbatch may be prepared in the form of pellets from a masterbatch composition comprising an antimicrobial-antifungal agent, an organic-inorganic reinforcing agent, and a masterbatch base resin.

[0036] The above antibacterial and antifungal agent may be modified sulfur. Generally, sulfur possesses the ability to inhibit bacteria and fungi due to its physiological toxicity; additionally, when added to materials such as polymers or rubber, it can form intermolecular cross-links, thereby improving the elasticity, resilience, heat resistance, and chemical resistance of the material. The modified sulfur used in the present invention is also a widely used functional antibacterial and antifungal agent that can provide antibacterial properties when used in concrete or cement-based building structure compositions.

[0037] However, using ordinary sulfur has the disadvantage that some of it participates in polymer cross-linking, which can lead to a relative decrease in antibacterial effect. To overcome this, modified sulfur is added so that it has a higher cross-linking strength compared to ordinary sulfur, thereby providing an improved antibacterial and antifungal effect.

[0038] Specifically, the modified sulfur above can be obtained by melt-mixing 0.1 to 100 weight% of a dicyclopentadiene-based modifier and 0.01 to 200 weight% of heterocyclic amines or alkylamines with respect to 100 weight% of sulfur at 120 to 160°C to obtain liquid modified sulfur, and then cooling the mixture to obtain the modified sulfur. This is included in the masterbatch composition of the present invention, and furthermore, the polyethylene sheet containing it has improved antibacterial and antifungal properties, allowing for flexibility while simultaneously providing waterproof and antibacterial functions, and can be easily applied to stainless steel composite panels of concrete structures.

[0039] It is preferable to include the above modified sulfur in an amount of 3 to 5 parts by weight per 100 parts by weight of the masterbatch base resin to provide compatibility with the components of the masterbatch composition and excellent antimicrobial properties. Less than 3 parts by weight results in weak antimicrobial and antifungal properties, while more than 5 parts by weight may impair the physical properties of the polyethylene sheet.

[0040] The above organic-inorganic reinforcing agent comprises an organic reinforcing agent and an inorganic reinforcing agent; specifically, nanocellulose may be used as the organic reinforcing agent and titanium dioxide as the inorganic reinforcing agent. Additionally, the above organic-inorganic reinforcing agent may include a modifying compatibilizer to functionalize the organic reinforcing agent and the inorganic reinforcing agent to facilitate application to a polyethylene sheet.

[0041] The above nanocellulose is an eco-friendly material derived from nature, is harmless to the human body, lightweight, and possesses characteristics such as transparent optical properties and a low coefficient of thermal expansion. In particular, it has high strength and elastic modulus, allowing it to be applied in various fields and provide excellent tensile strength. Furthermore, it has the advantage of possessing various functionalities by being able to be modified to be hydrophilic or hydrophobic by utilizing the reactivity of hydroxyl groups (-OH) present on the surface. It can be compatible with the components of the masterbatch composition within a range of 1 to 3 parts by weight per 100 parts by weight of the masterbatch base resin, and can subsequently provide excellent tensile strength to polyethylene sheets.

[0042] The titanium dioxide mentioned above is included as a functional inorganic reinforcing agent to improve the appearance uniformity, shape stability, and long-term durability of the polyethylene sheet attached to the stainless steel panel. It can improve the surface hardness of the polyethylene sheet, and enhance scratch resistance and wear resistance, thereby facilitating the manufacturing process and contributing to the durability of the composite panel. The durability and weather resistance of the polyethylene sheet are excellent when included in a range of 15 to 25 parts by weight per 100 parts by weight of the masterbatch base resin.

[0043] The above-mentioned modifying compatibilizer may be a polyolefin-based modified resin containing polar functional groups, and specifically, may be one or more selected from maleic anhydride-grafted polyethylene, acrylic acid-grafted polyethylene, and glycidyl methacrylate-grafted polyethylene. More preferably, maleic anhydride-grafted polyethylene (PE-g-Ma) having a melt index of 0.5 to 3 g / 10 min (2.16 kg) and a density of 0.91 to 0.93 g / cm³ (23°C) may be used. The above-mentioned polyolefin-based modified resin containing polar functional groups provides polar functional groups, such as carboxyl or hydroxyl groups, to polyethylene that is originally non-polar, thereby inducing interaction with polar functional groups that may be present on the surface of the organic and inorganic reinforcing agents, which can improve the compatibility between the components. Additionally, by including the above-mentioned modifying compatibilizer, a mutually complementary effect of elongation and tensile strength is provided, allowing both physical properties to be improved simultaneously. It is desirable to include the above-mentioned modified compatibilizer in an amount of 2 to 5 parts by weight per 100 parts by weight of the masterbatch base resin, as this modifies the surface of the organic reinforcing agent and the inorganic reinforcing agent to improve compatibility.

[0044] The masterbatch containing the above antibacterial-antifungal agent and organic-inorganic reinforcing agent may include a masterbatch base resin in addition to the above components. The masterbatch base resin may be linear low-density polyethylene (LLDPE), specifically having a melt index of 0.9 to 1.3 g / 10 min (2.16 kg) and a density of 0.921 to 0.925 g / cm³ (23°C). It is preferable to use the linear low-density polyethylene in powder or pellet form, as this provides excellent processability and resistance to yellowing. Since the masterbatch base resin uses polyethylene with the same components as the base resin of the polyethylene sheet composition, uniform mixing with the resin can be achieved during extrusion.

[0045] The masterbatch containing the above antimicrobial-antifungal agent and organic-inorganic reinforcing agent may be mixed with 3 to 5 parts by weight of the antimicrobial-antifungal agent, 16 to 38 parts by weight of the organic-inorganic reinforcing agent, and 2 to 5 parts by weight of the modified compatibilizer relative to 100 parts by weight of the masterbatch base resin in the masterbatch composition, and specifically, the organic-inorganic reinforcing agent may be included in an amount of 1 to 3 parts by weight of the organic reinforcing agent and 15 to 25 parts by weight of the inorganic reinforcing agent. In addition, additives such as pigments, dispersants, fluidity improvers, antioxidants, and heat stabilizers may be further included, and the components and their contents may be used without limitation as long as they are within the conventional range in the art.

[0046] The above masterbatch composition can be placed in a kneader and kneaded, and then the aged dough-like composition can be manufactured into a pellet-shaped masterbatch with a size of about 2 to 5 mm through a melt injection molding process using a twin-screw extruder and mixed into a polyethylene sheet composition. The mixing ratio may include 2 to 10 parts by weight per 100 parts by weight of the polyethylene resin, and within this range, a polyethylene sheet with excellent cold resistance and flexibility can be manufactured.

[0047] The substrate layer of the structure of the stainless steel composite panel of the present invention, which includes such a polyethylene sheet, may be concrete or steel, and can be installed for structural reinforcement in various structures.

[0048] The above stainless steel composite panel may be formed by laminating an adhesive film onto a plate-shaped plate formed on a substrate layer of a structure, and then laminating the polyethylene sheet. The adhesive film may form an adhesive layer by applying an adhesive, and the adhesive may be an adhesive such as epoxy, ethylene vinyl acetate, or polyurethane, but is not limited to any adhesive commonly used in the industry.

[0049] Hereinafter, a stainless steel composite panel containing a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties according to the present invention will be described in more detail through examples. However, the following examples are merely for reference to explain the present invention in detail, and the present invention is not limited thereto and can be implemented in various forms.

[0050] Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as generally understood by one of the art to which the present invention pertains. The terms used in the description herein are merely for the purpose of effectively describing specific embodiments and are not intended to limit the present invention.

[0052] 1. Test of physical properties of polyethylene sheets according to polyolefin elastomer content

[0054] Masterbatch Preparation

[0055] First, 20 g of titanium dioxide and 2 g of nanocellulose were mixed, and 4 g of maleic anhydride-grafted polyethylene (density 0.92 g / cm³, melt index 0.5~3 g / 10 min) was mixed. Subsequently, 4 g of modified sulfur and 6 g of pigment were mixed, and the mixture was stirred with 100 g of LLDPE 1 (Lotte Chemical, density 0.924 g / cm³, melt index 1.2 g / 10 min) to prepare a masterbatch composition. The masterbatch compositions were each fed into an extruder and extruded and cut at 150~170°C to produce the masterbatch in pellet form.

[0057] Polyethylene Sheet Manufacturing

[0058] A polyethylene sheet composition was prepared by stirring 1,000 g of LLDPE 2 (DL Chemical, density 0.920 g / cm³, melt index 2.0 g / 10 min), 1,000 g of ethylene-1-octene copolymer (LG Chem, density 0.872 g / cm³, melt index 5.24 g / 10 min), and 50 g of the above masterbatch. The composition was fed into an extruder, the temperature was sequentially raised from 110 to 180°C until melting occurred, and then extruded into a sheet shape at 50°C to produce a polyethylene sheet. In addition, polyethylene sheets were prepared by varying the polyolefin elastomer content as shown in Table 1.

[0059] (Weight portion) LLDPE 2 Polyolefin elastomer Masterbatch Preparation Example 1 100 75 5 Preparation Example 2 100 100 5 Preparation Example 3 100 125 5

[0061] <Evaluation of Physical Properties>

[0062] The polyethylene sheets of Manufacturing Examples 1 to 3 above were cut into plate shapes, and tensile strength and elongation were measured according to the test standard of KS M ISO 527-2:2013, durometer hardness was measured according to the test standard of KS M ISO 868:2004, and tensile strength, yield strength, and elongation were measured according to the test standard of KS B 0802:2004 (No. 5 test specimen). Adhesion strength was measured according to the test standard of KS M 4624:2016, specifically the adhesion strength with a two-component epoxy adhesive, and the results according to the above test items are shown in Table 2 below.

[0063] (Test method) KS M ISO 527-2 : 2013 KS M ISO 868 : 2004 KS M 4624 : 2016 (Test Items) Tensile strength (MPa) Growth rate (%) Durometer Hardness (Type A) Adhesion strength (MPa) Preparation Example 1 12.5 355 97 0.6 Preparation Example 2 13.2 361 99 0.8 Preparation Example 3 12.9 362 97 0.8

[0065] 2. Testing of antibacterial-antifungal and physical properties of polyethylene sheets according to masterbatch composition

[0067] Polyethylene Sheet Manufacturing

[0068] Since the polyethylene sheet of Manufacturing Example 2 above has excellent physical properties, the content of LLDPE 2 and polyolefin elastomer was fixed, but the polyethylene sheet was manufactured by varying the amount of the composition as shown in Table 3 below when manufacturing the masterbatch.

[0069] (Weight portion) Masterbatch LLDPE 1 titanium dioxide nanocellulose PE-g-Ma Modified sulfur Example 1 100 20 2 4 3 Example 2 (=Preparation Example 2) 100 20 2 4 4 Example 3 100 20 2 4 5 Comparative Example 1 100 20 2 4 7 Comparative Example 2 100 20 2 4 1 Comparative Example 3 100 20 2 1 4 Comparative Example 4 100 20 0.5 4 4 Comparative Example 5 100 10 2 4 4 Comparative Example 6 100 30 2 4 4

[0071] <Evaluation of Antimicrobial Properties>

[0072] The polyethylene sheets of Example 2 and Comparative Examples 1 and 2 were cut into plate shapes, and Staphylococcus aureus and Klebsiella pneumoniae were injected at 30±0.5℃ according to the test standard of KS K 0693. The antibacterial properties were evaluated by measuring the concentration of the remaining bacteria after 24 hours, and the results are shown in Table 4 below.

[0073] (Test Items) Staphylococcus aureus Klebsiella pneumoniae Initial concentration (CFU / mL) Concentration after 24 hours (CFU / mL) Bacteria reduction rate (%) Initial concentration (CFU / mL) Concentration after 24 hours (CFU / mL) Bacteria reduction rate (%) Example 2 1.5×10 5 < 10 99.9 2.5×10 5 < 10 99.9 Comparative Example 1 1.5×10 5 < 10 99.9 2.5×10 5 < 10 99.9 Comparative Example 2 1.5×10 5 4.0×10 5 - 2.5×10 5 2.9×10 5 -

[0075] <Evaluation of Antifungal Properties>

[0076] The Halo test (ASTMG-21) method was applied to the polyethylene sheet of Example 2 above, and the growth of fungal strains (mixed strains) was observed at 35°C, and the results are shown in Table 5 below. Aspergillus niger ATCC 9642, Penicillium pinophilum ATCC 11797, and Chaetomium globosum ATCC 6205 were used as the mixed strains.

[0077] (Time elapsed) 1 week later 2 weeks later 3 weeks later 4 weeks later Example 2 0 0 0 0

[0078] * 0: No bacterial growth detected in the sample.

[0080] <Evaluation of Physical Properties>

[0081] The polyethylene sheets of Examples 1, 2, and 3 and Comparative Examples 1, 3, 4, 5, and 6 were cut into plate shapes and tested according to the physical property test items, and the results are shown in Table 6 below.

[0082] (Test method) KS M ISO 527-2 : 2013 KS M ISO 868 : 2004 KS M 4624 : 2016 (Test Items) Tensile strength (MPa) Growth rate (%) Durometer Hardness (Type A) Adhesion strength (MPa) Example 1 13.1 360 98 0.8 Example 2 (=Preparation Example 2) 13.2 361 99 0.8 Example 3 13.2 360 99 0.8 Comparative Example 1 12.5 355 98 0.7 Comparative Example 3 12.6 358 98 0.8 Comparative Example 4 12.3 350 97 0.7 Comparative Example 5 12.4 357 89 0.8 Comparative Example 6 11.9 336 99 0.7

[0084] Referring to Tables 3 to 6 above, the polyethylene sheet of Example 2 of the present invention, containing modified sulfur, showed a bacterial reduction rate of 99.9% or higher, and was found to have excellent antifungal properties as no mold growth was confirmed. In Comparative Example 2, the modified sulfur was less than 3 parts by weight, and bacteria were observed. Although Comparative Example 1 showed excellent antibacterial and antifungal properties, the tensile strength and elongation were reduced in the physical properties test, indicating that the appropriate content of modified sulfur is 3 to 5 parts by weight.

[0085] Comparative Example 3 contained less than 2 parts by weight of a modifying compatibilizer, and although the elongation was excellent, the tensile strength was not improved, so the complementary effect of the physical properties was negligible. Comparative Example 4, containing 0.5 parts by weight of the above nanocellulose, had a tensile strength that decreased to 12.3 MPa.

[0086] It can be confirmed that Comparative Example 5 contains less than 15 parts by weight of titanium dioxide, resulting in a significantly reduced hardness. Comparative Example 6 contains more than 25 parts by weight of titanium dioxide, which has excellent hardness but reduced tensile strength and elongation, confirming that when titanium dioxide is included in amounts of 15 to 25 parts by weight, the hardness can be 98 or higher.

[0087] Accordingly, the polyethylene sheet of the present invention comprises a polyethylene resin; a polyolefin elastomer; and an antimicrobial-antifungal agent and an organic-inorganic reinforcing agent; wherein the polyolefin elastomer is included in an amount of 80 to 120 parts by weight per 100 parts by weight of polyethylene resin, and the antimicrobial-antifungal agent and the organic-inorganic reinforcing agent may be included as a masterbatch prepared from a composition comprising an antimicrobial-antifungal agent and an organic-inorganic reinforcing agent. The masterbatch may comprise 2 to 10 parts by weight per 100 parts by weight of polyethylene resin.

[0088] In particular, when the above composition contains 1 to 3 parts by weight of an organic reinforcing agent, 15 to 25 parts by weight of an inorganic reinforcing agent, and 2 to 5 parts by weight of a modifying compatibilizer relative to 100 parts by weight of a masterbatch base resin, it can be seen that various physical properties are simultaneously improved, such as a tensile strength of 13.1 MPa or higher, an elongation of 360% or higher, a durometer hardness of 98 or higher, and an adhesion strength of 0.8 MPa or higher. In addition, it was confirmed that the antibacterial and antifungal properties are excellent when the above composition contains 3 to 5 parts by weight of an antibacterial and antifungal agent.

[0089] Although the present invention has been described above through specific details and limited embodiments, this is provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

[0090] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

Claim 1 A stainless steel composite panel formed on a substrate layer of a structure, comprising: a plate-shaped plate of a certain thickness made of stainless steel material; an adhesive film; and a polyethylene sheet having excellent surface hardness and antibacterial-antifungal properties, comprising 2 to 10 parts by weight of a masterbatch composition containing 80 to 120 parts by weight of a polyolefin elastomer and an antibacterial-antifungal agent and an organic-inorganic reinforcing agent per 100 parts by weight of linear low-density polyethylene resin; wherein the masterbatch composition comprises 3 to 5 parts by weight of modified sulfur as the antibacterial-antifungal agent, 1 to 3 parts by weight of nanocellulose, 15 to 25 parts by weight of titanium dioxide, and 2 to 5 parts by weight of a modified compatibilizer as the organic-inorganic reinforcing agent, per 100 parts by weight of linear low-density polyethylene resin as the masterbatch base resin. Claim 2 delete Claim 3 delete Claim 4 A stainless steel composite panel according to claim 1, characterized in that the polyolefin elastomer has a melt index of 4.30 to 5.70 g / 10 min and a density of 0.868 to 0.873 g / cm³. Claim 5 delete Claim 6 delete Claim 7 A stainless steel composite panel according to claim 1, characterized in that the modification compatibilizer is a polyolefin-based modified resin containing polar functional groups. Claim 8 A stainless steel composite panel according to claim 1, characterized in that the substrate layer of the structure is concrete or steel.