Antibacterial resin molding

Abstract

To provide a novel antibacterial resin molded article and a method for forming the same. SOLUTION: The antibacterial resin molded article has a plurality of nanospikes protruding from the resin surface, and is obtained by treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma.

Description

[Technical Field]

[0001] The present invention relates to an antibacterial resin molded article and a method for forming the same. [Background technology]

[0002] Existing antibacterial technologies include direct use of antibacterial agents (antibacterial sprays containing alcohol, wet paper, etc.) and mixed use (photocatalytic TiO2 and antibacterial Ag). + They are mainly classified into two types: antibacterial agents (antibacterial agents containing antibacterial agents, etc.) and antibacterial agents containing antibacterial agents (antibacterial agents containing antibacterial agents, etc.). The former is highly effective but does not last as long because it uses a volatile liquid. The latter has a long-lasting effect, but is not as effective as the former. It requires technology to mix the antibacterial substance into the base material, and the antibacterial effect of the antibacterial substance lasts for about several years. Also, because it is mixed in, it is difficult to use photocatalytic TiO2 or antibacterial Ag. + The utilization efficiency of antibacterial substances such as the active species generated from the photocatalyst and antibacterial Ag is low. + Not only is it ineffective against bacteria that are resistant to it, but there is also concern that it could lead to the emergence of resistant bacteria.

[0003] The present invention relates to a technology for imparting antibacterial properties to a resin molded article that is independent of the shape of the base material, by applying biomimetics (biological simulation technology). Biomimetics is a technology that artificially imitates the diverse functions of living organisms in nature. The surface of the cicada's wings has minute irregularities of a few hundred nanometers, which are known to have excellent antibacterial properties. The mechanism of this antibacterial effect has not been fully elucidated, but one theory is that this irregular structure damages bacteria, causing them to leak body fluids and die, resulting in the antibacterial properties. These dead bacteria act as food to attract new bacteria, which are then killed by the microscopic structure as they feed. This cycle of antibacterial properties is expected to occur. Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, methods for forming fine protrusions on a substrate surface, such as by imprinting or reactive ion beam etching, have been known, but a method for forming nanospikes on a thermoplastic resin surface by treating the surface of the resin containing a solvent with atmospheric pressure plasma has not been known. [Means for solving the problem]

[0005] The present invention provides an antibacterial resin molded article having a novel antibacterial surface. Specifically, the present invention relates to an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, which is obtained by treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma.

[0006] The present invention further relates to an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, which is obtained by treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma and then closing the pores in the resin.

[0007] The present invention further relates to an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, which is obtained by treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma and then annealing the article, using annealing as a method for closing pores in the resin.

[0008] In one embodiment of the invention, the nanospikes have a pitch of 10-1000 nm and a height of 20-300 nm. In one embodiment of the invention, the tip angle of the nanospikes is 80 degrees or less.

[0009] In one embodiment of the present invention, the thermoplastic resin is selected from the group consisting of polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polyethyl methacrylate, polypropyl methacrylate, polyvinylidene fluoride, polystyrene, poly-α-methylstyrene, poly-4-methylstyrene, polyvinylphenol, polybenzyl methacrylate, and polycyclohexyl methacrylate.

[0010] In one embodiment of the invention, the solvent is selected from the group consisting of ethyl lactate, xylene, toluene, NMP (N-methyl-2-pyrrolidone), DMF (N,N-dimethylformamide), DMAc (dimethylacetamide), PGMEA (propylene glycol monomethyl ether acetate).

[0011] The present invention further relates to a method for forming an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, which comprises treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma.

[0012] The present invention further relates to a method for forming an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, which comprises treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma and then closing the pores in the resin.

[0013] The present invention further relates to a method for forming an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, which comprises treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma and then annealing the surface.

[0014] In the antibacterial resin molding of the present invention, it is believed that the tips of the multiple nanospikes damage the surface of bacteria that come into contact with the resin molding, thereby killing the bacteria. [Brief explanation of the drawings]

[0015] [Figure 1] Flow diagram showing nanospike formation by atmospheric pressure plasma treatment [Figure 2] Diagram showing pore sealing by annealing treatment [Figure 3] View of the upper electrode of the plasma irradiation device from below [Figure 4] Cross-sectional view of plasma irradiation device [Figure 5] AFM observation of the cross-sectional contour of the nanospike [Figure 6] Graph showing the relationship between the number of plasma exposures and surface roughness [Figure 7]Graph showing the change in contact angle due to annealing treatment DETAILED DESCRIPTION OF THE INVENTION

[0016] As used herein, the term "thermoplastic resin" refers to a resin that softens when heated to its glass transition temperature or melting point. In this specification, the term "atmospheric pressure plasma" refers to non-thermal equilibrium plasma that is generated under atmospheric pressure. As used herein, the term "antibacterial" refers to both killing microorganisms such as viruses, fungi, molds, yeasts, and bacterial spores, and inactivating them to inhibit their growth. Furthermore, in this specification, the above-mentioned microorganisms such as viruses, fungi, molds, yeasts, and bacterial spores may be collectively referred to as "bacteria." In this specification, the term "nanospike" refers to a protrusion of nano-order size with a sharp tip, which differs from the broad definition of nanospikes that includes cylindrical protrusions. In this specification, the term "pores" refers to voids in a resin with diameters on the order of nanometers that are formed by evaporation of a solvent and that are interconnected.

[0017] In the present invention, as will be described in detail later, pores are formed by evaporation of the solvent in the resin, and during plasma treatment, a plasma jet penetrates the resin through these pores and scrapes the resin, forming nanospikes. Closing the pores after plasma treatment improves antibacterial properties, so such treatment is recommended. Annealing is the most common method for closing the pores, but other known methods can also be used.

[0018] In this specification, the term "annealing treatment" refers to a treatment for removing residual stress in a resin molded product by applying heat, and in the present invention, annealing treatment is performed to close pores formed by evaporation of the solvent.

[0019] The thermoplastic resin used in the present invention may be any known resin that can be dissolved or swollen by a suitable solvent. Non-limiting examples of thermoplastic resins include polyethylene (including linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and high-density polyethylene (HDPE)), polypropylene, other polyolefin resins, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), perfluoroethylenepropene copolymer (FEP), polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVDC), non-aromatic polyamides (including nylon 6, nylon 66, and nylon 12), non-aromatic polyimides, polyacetal (POM), polyurethane, ethylene-vinyl alcohol copolymer (EVOH), polyvinyl chloride (PVC), acrylic polymers, ethylene-vinyl acetate copolymer (EVA), polylactic acid (PLA), polycaprolactone (PCL), and polyglycolic acid (PGA). These include terpolymers (including polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polybutylene naphthalate (PBN), etc.), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), semi-aromatic polyamides, fully aromatic polyamides, semi-aromatic polyimides, fully aromatic polyimides, polystyrene (PS), acrylonitrile-styrene copolymers (AS), acrylonitrile-butadiene-styrene copolymers (ABS), polycarbonate (PC), polyarylate (PAR), polyphenylene ether (PPE), polyphenolic resins, and aromatic epoxy resins; and rubbers such as isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), ethylene-propylene rubber (EPM), and other thermoplastic elastomers (including SEBS, SBS, and SEPS, etc.).Examples of suitable thermoplastic resins include polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polyethyl methacrylate, polypropyl methacrylate, polyvinylidene fluoride, polystyrene, poly-α-methylstyrene, poly-4-methylstyrene, polyvinylphenol, polybenzyl methacrylate, and polycyclohexyl methacrylate.

[0020] The molded article of the present invention may optionally contain additives to adjust its properties depending on the application. Examples of such additives include known fillers, lubricants, plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weatherproofing agents, antistatic agents, antioxidants, and colorants (dyes, pigments). These additives can be used in optimal combinations as long as they do not impair the effects of the present invention. Depending on the application and requirements, other additives may also be used, such as organic substances (including other polymers) and inorganic substances such as metal nanoparticles.

[0021] The resin molded article of the present invention may be a mixture of two or more resins. The molded article may also be combined with other materials, for example, by forming a thermoplastic resin film on another substrate to form the molded article.

[0022] The solvent used in the present invention can be appropriately selected depending on the resin used, and selecting a suitable solvent is a matter that can be easily done by those skilled in the art. Examples of suitable solvent combinations for suitable resins include xylene for polyethylene, xylene for polypropylene, ethyl lactate or N-methyl-2-pyrrolidone (NMP) for polymethyl methacrylate, ethyl lactate for polyethyl methacrylate, ethyl lactate for polypropyl methacrylate, N,N-dimethylformamide (DMF) or dimethylacetamide (DMAc) for polyvinylidene fluoride, ethyl lactate or propylene glycol monomethyl ether acetate (PGMEA) for polystyrene, ethyl lactate or PGMEA for poly-α-methylstyrene, ethyl lactate or PGMEA for poly-4-methylstyrene, ethyl lactate for polyvinylphenol, xylene for polybenzyl methacrylate, and xylene for polycyclohexyl methacrylate.

[0023] The amount of solvent is preferably 10-40 wt %, more preferably 15-30 wt %, of the total weight of the resin composition to be formed. For example, when spin-coating, if the amount of solvent is too large, the solution will fly off due to centrifugal force during spin-coating, and the entire surface will not be coated evenly. On the other hand, if the amount of solvent is too small, the composition will not spread well during spin-coating, and the entire surface will not be coated evenly. Furthermore, in known thermoplastic resin molding methods such as solution casting, the appropriate solvent amount is considered to be in the above range from the viewpoints of workability and the quality of the molded product. Furthermore, the viscosity of the resin composition is preferably 0.5-400 cP, more preferably 5-50 cP.

[0024] The shape of the molded article is not particularly limited and can be selected as desired depending on the application. For example, the molded article can be in the form of a film, sheet, plate, bag, tube, fiber, mesh, a predetermined shape, or an amorphous solid body. The resin may be molded after undergoing antibacterial treatment, or the antibacterial treatment may be performed after molding.

[0025] In the following, an example in which a thermoplastic resin is applied to a substrate will be described, but the antibacterial surface of the molded article of the present invention can be obtained by similar procedures in other molding methods.

[0026] After applying a solvent-containing resin to a substrate, it is preferable to heat the resin to evaporate the solvent and quickly form pores on the surface of the resin film. However, since pores can also be formed by drying at room temperature, heating is not an essential condition.

[0027] This is shown in Figure 1. In the diagram on the left, when the solvent shown by the black circles in the resin film evaporates due to heating or other reasons, traces of the evaporated solvent remain as pores shown by the white lines. Nanospikes are formed by blowing a plasma jet from a hole into the interior of the film, as indicated by the arrow in the center of Figure 1. Simply put, a plasma jet is a gas flow of charged particles that can be blown into the interior if the pores are connected like mole holes. In doing so, the surface of the resin and the sides of the pores are scraped away, as shown in the diagram on the right side of Figure 1, and the remaining parts are thought to become nanospikes.

[0028] In the present invention, atmospheric pressure plasma treatment is performed by applying a high voltage to an electrode while flowing helium (He) and oxygen (O) to generate atmospheric pressure plasma, which is then brought into contact with the resin surface. The helium flow rate is preferably 0.3-20 L / min, more preferably 0.5-10 L / min, and most preferably 0.7-5.0 L / min. The oxygen flow rate is preferably 1-300 mL / min, more preferably 1-200 mL / min, and most preferably 1-100 mL / min. Note that in this specification, flow rates are indicated at 0°C and 1 atmosphere. The ratio of oxygen to helium (oxygen gas flow rate / helium gas flow rate) is 0.27-5%, preferably 0.27-3.3%, for example, 4 sccm / 1500 sccm to 50 / 1500 sccm.

[0029] Power density is preferably 25-2000W / cm 3 , more preferably 50-1000W / cm 3, most preferably 100 to 700 W / cm 3 is. In the present invention, plasma processing is performed at atmospheric pressure, so the frequency of the applied power is on the order of MHz, which makes it possible to avoid the risk of deformation or damage to the object to be processed due to dielectric heating.

[0030] In the present invention, the term nanospike refers to a protrusion having a size on the order of nano-size and a sharp tip. The distance between the apexes of the nanospikes is referred to herein as the nanospike pitch, and is preferably 10-1000 nm, more preferably 50-500 nm, more preferably 100-200 nm.

[0031] The height from the thermoplastic resin surface is preferably 20-300 nm, more preferably 30-200 nm, more preferably 50-150 nm. The ratio of the base diameter to the height is preferably 0.1-1.0, more preferably 0.2-0.75, more preferably 0.25-0.5. The base of the nanospike refers to the plane parallel to the resin surface at the lowest point of the nanospike determined by the AFM image, and the height refers to the distance from the base to the highest point of the nanospike.

[0032] The nanospikes preferably have a shape such that the diameter in a cross section parallel to the thermoplastic resin surface decreases monotonically in the height direction. In the present invention, the tip angle of the nanospike is preferably 80 degrees or less, more preferably 70 degrees or less, and even more preferably 60 degrees or less. In this specification, the tip angle of the nanospike refers to the smallest angle at which the outline of a cross section containing the apex of the nanospike intersects with the resin surface. The tip angle can be determined by extracting a cross section from an AFM image and observing the tip angle.

[0033] The following four conditions are thought to be the main factors that contribute to the sharpness of the nanospike tips. 1) Density and pore distribution of residual solvent, plasma lighting power, and irradiation time 2) Drying conditions (temperature and time) that determine the density of the residual solvent (it is better to collect on the surface of the film) 3) The concentration and viscosity of the solvent (compatibility with the solvent) and drying conditions determine the pore size distribution. 4) Plasma lighting power, which affects the rate of plasma decomposition

[0034] Also, the power affects the strength of the jet, so a higher power is preferable, but if the power is too high, the temperature will rise too much, causing the microstructure to soften or decompose. Experimentally, high power and short irradiation times give good results.

[0035] It is believed that the height of the nanospikes can be increased by delivering the jet deep into the pores in a short time without increasing the surface temperature. The number of nanospikes per unit area is 1-10,000 / mm, calculated based on the distance between the apexes of the preferred nanospikes described above. 2 , preferably 4-400 / mm 2 , more preferably 25-100 / mm 2 In order to obtain a suitable antibacterial property, it is preferable that the nanospikes are densely packed in a certain area.

[0036] The area in which the nanospikes are formed may be the entire resin surface or a part of the resin surface.

[0037] As mentioned above, the film thickness decreases as the resin is scraped away by the plasma jet. Since the shallower film thickness is the area where the pores are concentrated, it is preferable to reduce the number of plasma treatments, for example, 6 to 8 times, and the irradiation time per treatment is also short.

[0038] During this abrasive reaction (known as plasma etching in semiconductor processes), the film is softened by heat, and heat is taken away by the decomposition and vaporization of the solvent near the surface, which is expected to have the effect of suppressing the temperature rise of the film (local heating by plasma). In summary, it is thought that a combination of the "abrasive reaction caused by the plasma penetrating" and the "effect of the heat of vaporization when the solvent evaporates" results in the formation of a microstructure in a shallow layer on the surface.

[0039] The changes caused by annealing are shown in Figure 2. By performing an operation to close pores, such as annealing, the residual stress in the resin is eliminated, the pores inside the resin are sealed, and the connections between the pores, like mole holes, are closed.

[0040] The surface of a molded product that has only been plasma treated is hydrophilic, but when it is annealed, the surface properties change to water repellency. In terms of surface shape, the height of the nanospikes appears to be slightly lower and the tips appear to be sharper on an AFM.

[0041] When a water droplet is dropped onto the surface, there is air between the droplet and the microstructure, but if the pores are not blocked, the air can escape through the "mole tunnel" to areas where there are no water droplets, and the water droplets can seep into the gaps in the microstructure by capillary action. Therefore, the resin film surface that has only been treated with plasma has what is known as ultra-nanohydrophilicity.

[0042] When the pores are sealed by annealing and the mole tunnels are blocked, there is no escape route for the air, and the trapped air can repel water droplets, which is thought to make the material water-repellent.

[0043] Suitable annealing conditions vary depending on the type of resin, but can be easily determined by a person skilled in the art. For example, the conditions can be determined by measuring the contact angle to provide the desired properties.

[0044] The molded article of the present invention has antibacterial properties against a wide variety of bacteria. Antibacterial properties are determined by inoculating bacteria and measuring the number of viable bacteria immediately after inoculation and 24 hours after inoculation according to the method described in JIS Z 2801 (2012). If the number of viable bacteria is significantly reduced compared to an untreated reference sample, it is determined to have antibacterial properties.

[0045] These molded articles may have antibacterial properties imparted to at least a portion of their surface, but may also have antibacterial properties imparted to the entire surface. When it is possible to predict the parts that may come into contact with bacteria during use, or the parts that may come into contact with food, medicines, or living organisms, it is sufficient to impart antibacterial properties to at least those parts. These molded articles may have antibacterial properties imparted to their outer surface, or, when they have a bag-like or tubular shape, may have antibacterial properties imparted to their inner surface.

[0046] The molded article of the present invention can be used alone, but can also be used as a composite material by integrating it with another substrate by fusion or adhesion, etc. The other substrate can be, for example, a resin, a metal, a ceramic, a glass, etc., and can be selected depending on the application.

[0047] The molded articles of the present invention are effective in eliminating, reducing cell survival, and reducing cell growth and / or proliferation of a wide range of cells, including both prokaryotic and eukaryotic cells, particularly Gram-positive and Gram-negative bacterial cells (including spores), plant cells (such as algae), animal cells, marine and aquatic cells, fungal cells (such as yeast), protist cells, helminth cells, and other microbial cells such as protozoa, archaea, rotifers, and planarians. Virus-infected cells may also be eliminated in accordance with the present invention. The present invention is particularly applicable to the elimination of cells or microorganisms, such as algae, molds, and fungi, particularly those that pose a threat to human or animal health. Specific examples of pathogenic and non-pathogenic cells or microorganisms that may be eliminated in accordance with the present invention include, but are not limited to, Pseudomonas aeruginosa, Pseudomonas fluorescens, Escherichia coli, Branhamella catarrhalis, Planococcus maritimus, Staphylococcus aureus, and Bacillus subtilis. In particular, because cell wall structure is one of the key determinants of cell stiffness and consequent sensitivity to mechanoresponsive surfaces, regardless of cell morphology or phylogenetic affiliation, the surface of the molded body of the present invention is expected to be lethal to other prokaryotic microorganisms with similar cell wall structures.

[0048] The resin molded articles can be used in a wide range of applications, including packaging, building equipment, home appliances, electronic devices and their peripherals, automotive parts, various coatings, medical equipment, agricultural products, stationery, and personal accessories. Examples of the above-mentioned building facilities include toilets and toilet seats, bathroom vanities, water and sewage pipes, foot mats, interior materials, and items that are touched by people on a daily basis, such as door handles, handrails, and switches. Examples of such home appliances include rice cookers, microwave ovens, refrigerators, irons, hair dryers, air conditioners, and air purifiers. Examples of the electronic devices and their peripherals include laptops, smartphones, tablets, digital cameras, medical electronic devices, POS systems, printers, televisions, mice and keyboards, etc. Examples of the above automotive parts include steering wheels, seats, shift levers, and various types of piping. Examples of such packaging include packaging for medicines, food, and the like. Examples of such coatings include coatings for walls, floors and ceilings of factories, operating rooms, storage facilities and shipping containers. Examples of the medical devices include forceps, syringes, stents, artificial blood vessels, catheters, wound dressings, scaffolding materials for tissue engineering, and adhesion barriers. Examples of the agricultural products include stretch films for agricultural greenhouses. Examples of the body accessories include clothing including outerwear and underwear, hats, shoes, gloves, diapers, napkins and storage bags thereof. The resin molded article can also be used to kill bacteria contained in building facilities, personal accessories, tableware, beverages, foodstuffs, etc. by contacting the molded article with the building facilities, personal accessories, tableware, beverages, foodstuffs, etc.

[0049] Example The present invention will be described in detail below with reference to examples. Polymer film preparation conditions The polymer used was polymethyl methacrylate (PMMA; MW = 15,000, manufactured by Sigma-Aldrich). PMMA was dissolved in ethyl lactate (Kanto Chemical Co., Ltd., Shika Grade 1) at a concentration of 30 wt%. The mixture was stirred at 600 rpm and 25°C for 3 hours. This solution was spin-coated onto a glass substrate (1 mm thick) at 1800 rpm for 24 seconds, and then baked in an oven at 100°C for 1 minute to produce a PMMA film approximately 5 μm thick.

[0050] Plasma treatment Plasma treatment was carried out using the plasma irradiation device shown in Figures 3 and 4. In the figures, A is the support and B is the upper electrode. The source gas used for plasma generation was a mixture of He (1500 ml / min) and O2 (60 ml / min). This gas was introduced into the upper electrode unit (length: 32 mm, width: 52 mm). The distance between the sample substrate and the upper electrode was 0.7 mm, and the distance between the upper electrode and the stage (lower electrode) was 1.7 mm. RF power of 120 W at 27.12 MHz was supplied between the upper and lower electrodes to generate atmospheric pressure low-temperature plasma. Each irradiation lasted for 5 seconds. A 15-second cooling period was then allowed before a second irradiation. Twelve irradiations were performed, each consisting of a 5-second irradiation and a 15-second cooling period.

[0051] Annealing The plasma-irradiated substrates were then annealed (120°C for 5 days). The surface shapes before and after each surface treatment were observed with an atomic force microscope (AFM), and the contact angles of the surfaces were measured with an automatic contact angle meter. The film thickness before annealing was 4.78 μm, but after annealing it was 4.50 μm. The decrease in film thickness is thought to be due to the closure of pores in the resin.

[0052] result Figure 5 shows the cross-sectional profile of the nanospikes observed by AFM. It can be seen that nanospikes with heights of approximately 100-200 nm and sharp tips are continuously formed.

[0053] The upper part of Figure 6 shows AFM images that demonstrate the changes in surface shape due to plasma exposure and annealing. The lower part of Figure 6 shows a graph that shows the relationship between the number of plasma exposures and surface roughness. It can be seen that plasma exposure results in the formation of nanospike structures, and that annealing reduces the resin film thickness.

[0054] The upper part of Figure 7 shows the change in contact angle due to plasma exposure and annealing treatment. The lower part of Figure 7 shows a graph showing the relationship between the number of plasma exposures and the contact angle after annealing treatment. There is no significant change in the contact angle depending on the number of plasma exposures, but it can be seen that in all cases the contact angle increases due to annealing treatment.

[0055] The antibacterial test was carried out under the following conditions. Antibacterial Testing Temperature: 35℃±1℃ Bacterial species: Escherichia NBRC 3972 Initial bacterial count: 3.7×10 5 CFU (Measurement of viable bacteria count) Media used: Standard agar medium Immediately after inoculation and 24 hours after inoculation, the viable cell count was measured according to the method described in JIS Z 2801 (2012). Evaluation was carried out on a sample that had undergone only plasma treatment (Example 1) and a sample that had undergone plasma treatment and annealing treatment (Example 2).

[0056] As a comparative example, a plastic bag (stomacher bag) for bacterial testing manufactured by Organo Corporation was cut into 5 x 5 cm pieces and used as an untreated PE sheet (Comparative Example 1). Also, a PMMA sheet (manufactured by Hikari Corporation, A000-3S) before plasma treatment was used as Comparative Example 2.

[0057] The results are shown below. Sample Bacteria count Example 1 2.7 x 10 6 Example 2 <10 Comparative Example 1 8.1 × 10 6 Comparative Example 2 9.3 × 10 6

[0058] It was shown that good antibacterial properties were obtained in the examples of the present invention.

Claims

1. An antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, obtained by treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma.

2. An antibacterial resin molded body having multiple nanospikes protruding from the resin surface, obtained by treating the surface of a solvent-containing thermoplastic resin molded body with atmospheric pressure plasma and then closing the pores in the resin.

3. An antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, obtained by treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma and then annealing it.

4. 4. The antibacterial resin molding according to claim 1, wherein the nanospikes have a pitch of 10 to 1000 nm and a height of 20 to 300 nm.

5. 5. The antibacterial resin molding according to claim 1, wherein the nanospikes have a tip angle of 80 degrees or less.

6. The thermoplastic resin is selected from the group consisting of polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polyethyl methacrylate, polypropyl methacrylate, polyvinylidene fluoride, polystyrene, poly-α-methylstyrene, poly-4-methylstyrene, polyvinylphenol, polybenzyl methacrylate, and polycyclohexyl methacrylate. The antibacterial resin molded article according to any one of claims 1 to 5.

7. The antibacterial resin molded article according to any one of claims 1 to 6, wherein the solvent is selected from the group consisting of ethyl lactate, xylene, toluene, NMP (N-methyl-2-pyrrolidone), DMF (N,N-dimethylformamide), DMAc (dimethylacetamide), and PGMEA (propylene glycol monomethyl ether acetate).

8. A method for forming an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, comprising treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma.

9. A method for forming an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, comprising treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma and then closing the pores in the resin.

10. A method for forming an antibacterial resin molded article having a plurality of nanospikes protruding from the resin surface, comprising treating the surface of a solvent-containing thermoplastic resin molded article with atmospheric pressure plasma and then annealing the surface.

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