Antibacterial resin composition

Abstract

According to the present invention, an antimicrobial resin composition contains a urethane resin, a lubricant, and, as antimicrobial agents, a hindered phenol derivative, a hindered amine derivative, and a benzotriazole derivative.

Description

Technical Field

[0001] The present disclosure relates to an antibacterial resin composition.

Background Art

[0002] Recently, due to the increasing trend towards cleanliness, there has been an increasing number of resin products being subjected to antibacterial treatment, particularly in products that are touched by a large number of unspecified users. Examples of antibacterial treatment methods include, for example, a method of kneading and dispersing an antibacterial agent in a resin, a method of applying an antibacterial coating to the resin surface, etc. Since an antibacterial agent can be kneaded into a resin during a resin molding process such as injection molding or extrusion molding, the method of kneading and dispersing an antibacterial agent in a resin is often implemented.

[0003] Conventional antibacterial agents are roughly classified into inorganic and organic antibacterial agents. Examples of inorganic antibacterial agents include those in which metal ions such as silver, zinc, and copper are supported on zeolite, silica gel, glass, calcium phosphate, etc. Examples of organic antibacterial agents include alcohol-based, thiazoline-based, imidazole-based, etc. Inorganic antibacterial agents have good heat resistance and weather resistance of antibacterial agent-containing resin products, but physical properties such as mechanical strength decrease, and due to containing metal ions, there are concerns about resin discoloration and the impact on the ecosystem due to mass consumption. Organic antibacterial agents do not reduce the mechanical strength of the product, but have drawbacks in heat resistance and weather resistance. Also, inorganic and organic antibacterial agents are costly. Therefore, it has been considered to use materials that are not normally used for antibacterial purposes as antibacterial agents.

[0004] For example, Japanese Patent Application Laid-Open No. 2008-31092 (Patent Document 1) discloses a resin molded article in which a hindered phenol derivative is blended as an antibacterial agent in a resin. Since the resin molded article is excellent in compatibility, moldability, thermal stability, safety, etc. between the resin and the antibacterial agent, it is also described that antibacterial resin molded articles and antibacterial articles excellent in moldability, transparency, thermal stability, safety, etc. are provided.

[0005] Furthermore, Japanese Patent Publication No. 10-265585 (Patent Document 2) discloses a resin molded article in which a hindered amine-based substance is compounded with a polyacetal resin as an antibacterial agent. It is also stated that this resin molded article maintains its mechanical properties while exhibiting excellent antifungal and antibacterial properties. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2008-31092 [Patent Document 2] Japanese Patent Application Publication No. 10-265585 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, as described in Patent Document 1, when a hindered phenol derivative is incorporated into a urethane resin, the hindered phenol derivative does not easily precipitate on the resin surface, and sufficient antibacterial properties cannot be obtained.

[0008] Furthermore, as described in Patent Document 2, when hindered amine substances are incorporated into urethane resin, it is common practice to add a lubricant to the urethane resin to improve the fluidity of the resin composition, moldability such as release properties from molds, and surface properties such as scratch resistance. However, the bleeding of the lubricant onto the resin surface inhibits the antibacterial properties, preventing sufficient antibacterial activity from being achieved.

[0009] Thus, even when hindered phenol derivatives or hindered amine-based substances are individually incorporated into urethane resins, sufficient antibacterial properties cannot be obtained.

[0010] This disclosure has been made in view of the above-mentioned problems, and aims to provide an antibacterial resin composition that has excellent antibacterial properties in a urethane resin containing a lubricant. [Means for solving the problem]

[0011] An antimicrobial resin composition containing a urethane resin, a lubricant, and a hindered phenol derivative, a hindered amine derivative, and a benzotriazole derivative as antimicrobial agents. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide an antibacterial resin composition that has excellent antibacterial properties in a urethane resin containing a lubricant. [Modes for carrying out the invention]

[0013] The embodiments of this disclosure will be described below.

[0014] Embodiment 1. <Antibacterial resin composition> The antibacterial resin composition of this embodiment contains a urethane resin, a lubricant, and antibacterial agents: a hindered phenol derivative (antibacterial agent A), a hindered amine derivative (antibacterial agent B), and a benzotriazole derivative (antibacterial agent C). Hereinafter, the hindered phenol derivative may simply be referred to as "antibacterial agent A," the hindered amine derivative as "antibacterial agent B," and the benzotriazole derivative as "antibacterial agent C."

[0015] In this embodiment, the antibacterial resin composition contains the above-mentioned antibacterial agents A to C, thereby achieving excellent antibacterial properties that are not affected by the lubricant. Each component will be described in detail below.

[0016] (urethane resin) The antibacterial resin composition of this embodiment is obtained by dispersing a lubricant and an antibacterial agent in a urethane resin. There are no particular restrictions on the urethane resin, and examples include thermoplastic urethane resins and thermosetting urethane resins. Examples of these resins include ether-based urethane resins, ester-based urethane resins, and carbonate-based urethane resins, and thermoplastic ether-based urethane resins are preferred from the viewpoint of excellent environmental resistance such as water resistance and weather resistance. These urethane resins may be used individually or in appropriate combinations of two or more as a polymer blend.

[0017] (Lubricant) The antibacterial resin composition of this embodiment contains a lubricant. By containing a lubricant, the fluidity of the urethane resin is improved, and the moldability is enhanced. There is no particular limitation on the lubricant. For example, fatty acid esters, higher alcohols, polyhydric alcohols, glycerin esters, sorbitan esters, fatty acids, fatty acid amides, oil-based waxes, etc. can be mentioned, and fatty acid amides are preferred. This is because fatty acid amides have low compatibility with the urethane resin and can improve the mold release property by depositing on the resin surface, and can smooth and reduce the friction of the surface of the molded product. These lubricants may be used alone or in appropriate combinations of two or more.

[0018] The content of the lubricant in this embodiment is 0.05 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the urethane resin. When the content of the lubricant is less than 0.05 parts by weight, the fluidity of the antibacterial resin composition, the moldability such as the mold release property from the mold, and the surface properties such as scratch resistance cannot be improved. When the content of the lubricant exceeds 20 parts by weight, the fluidity of the antibacterial resin composition becomes too good, and there is a risk that the moldability deteriorates, such as the urethane resin dripping.

[0019] (Hindered phenol derivative (Antibacterial agent A)) The antibacterial agent A contained in the antibacterial resin composition of this embodiment has a structure represented by the following chemical formula 1 in the molecule.

[0020] [Chemical formula] <s

[0021] In the above chemical formula 1, R is a hydrogen atom or an alkyl group.

[0022] As the antibacterial agent A used in this embodiment, known hindered phenol derivatives can be used. The antibacterial agent A of this embodiment can be roughly classified into two types: a first hindered phenol derivative antibacterial agent (antibacterial agent A1) with excellent compatibility with urethane resin and a second hindered phenol derivative antibacterial agent (antibacterial agent A2) with excellent solubility in lubricants, and contains at least one kind of antibacterial agent A1 and antibacterial agent A2 respectively.

[0023] As the antibacterial agent A1, it is preferably at least one selected from the group consisting of (1) pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], (2) thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], (3) N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], (4) 2,4-dimethyl-6-(1-methylpentadecyl)phenol, (5) calcium diethyl bis[[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate], (6) ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], (7) hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], (8) 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1, 3, 5-triazin-2-ylamino)phenol.

[0024] Antimicrobial agent A2 includes (9) dibutylhydroxytoluene, (10) octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, (11) 3,3',3”,5,5',5”-hexa-tert-butyl-a,a',a”-(mesitylene-2,4,6-triyl)tri-p-cresol, (12) 4,6-bis(octylthiomethyl) (13)1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, (14)1,3,5-Tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione Preferably, it is at least one selected from the group consisting of lyon, (15) 2,6-di-tert-butyl-4-methylphenol, (16) 2,2'-methylenebis(4-methyl-6-tert-butylphenol), (17) 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), (18) 4,4'-thiobis(3-methyl-6-tert-butylphenol), (19) 3,9-bis[2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro(5,5)undecane, and (20) 1,1,3-tris-(2-methyl-4-hydroxy-5-tert-butyl-phenyl)-butane.

[0025] Among these, (1) is more preferred as antibacterial agent A1 and (9) as antibacterial agent A2 in this embodiment, from the viewpoint of having excellent compatibility with urethane resin and lubricant.

[0026] (Hindered amine derivative (antibacterial agent B)) The antibacterial agent B contained in the antibacterial resin composition of this embodiment has a structure represented by the following chemical formula 2 in its molecule.

[0027] [ka]

[0028] In the above chemical formula 2, R is a hydrogen atom, an alkyl group, or an ether group.

[0029] As the antibacterial agent B used in this embodiment, known hindered amine derivatives can be used, including (1) bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, (2) poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6, 6- (3) Mixed esterified product of 1,2,3,4-butanetetracarboxylic acid, 2,2,6,6-tetramethyl-4-piperidinol, and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, (4) Tetrakis( It is preferable that the antibacterial agent B used in this embodiment is at least one selected from the group consisting of (5) 1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, (6) tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, and (6) bis[2,2,6,6-tetramethyl-1-(octyloxy)piperidine-4-yl] decandioate. Among these, (1) is more preferred as the antibacterial agent B used in this embodiment from the viewpoint of excellent compatibility with urethane resin.

[0030] (Benzotriazole derivative (antibacterial agent C)) The antibacterial agent C contained in the antibacterial resin composition of this embodiment has a structure represented by the following chemical formula 3 in its molecule.

[0031] [ka]

[0032] As the antibacterial agent C used in this embodiment, known benzotriazole derivatives can be used, including (1) 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, (2) 2-(2H-benzotriazole-2-yl)-4-methylphenol, (3) 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, (4) 2-(5-chloro-2H-benzotriazole-2-yl)-6-(1,1-dimethyl It is preferable that the antimicrobial agent C used in this embodiment is at least one selected from the group consisting of (5) 2,2-methylene-bis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl))phenol, (6) the reaction product of methyl 3-(3-(2H-2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl)propionate and PEG300, and (7) 2-(2H-benzotriazol-2-yl)-4-methyl-6-dodecylphenol. Among these, (1) is more preferred as the antimicrobial agent C used in this embodiment from the viewpoint of having excellent heat resistance.

[0033] (Antibacterial agents A-C) Antimicrobial agents A and C are thought to exhibit antimicrobial activity by denaturing enzyme proteins and inhibiting respiration, while antimicrobial agent B exhibits antimicrobial activity by disrupting cell membranes and cell walls. Furthermore, antimicrobial agents A1 and B are thought to have excellent compatibility with urethane resin and are therefore less likely to precipitate on the surface of the urethane resin, while antimicrobial agent A2 is easily soluble in lubricants, and antimicrobial agent C tends to bleed. Therefore, it is thought that the effect of antimicrobial agents A2 and C dissolved in the lubricant causes antimicrobial agents A1 and B, which are easily soluble in urethane resin, to precipitate and accumulate on the surface of the urethane resin, resulting in the expression of the above-mentioned antimicrobial activity against bacteria. Accordingly, it is preferable to select and add at least one of each of antimicrobial agents A1, A2, B, and C to the antimicrobial resin composition of this embodiment.

[0034] The total content of antibacterial agents A1, A2, B, and C in this embodiment is 0.2 to 20 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of urethane resin. If the total content of antibacterial agents A1, A2, B, and C is less than 0.2 parts by weight, sufficient antibacterial properties cannot be imparted to the antibacterial resin composition. If the total content of antibacterial agents A1, A2, B, and C exceeds 20 parts by weight, the physical properties of the antibacterial resin composition will deteriorate, which is undesirable, and since each antibacterial agent is more expensive than the resin, it is also undesirable from a cost standpoint. Furthermore, the individual content of antibacterial agents A1, A2, B, and C in this embodiment is 0.05 to 5 parts by weight, preferably 0.12 to 2.5 parts by weight, per 100 parts by weight of urethane resin.

[0035] Furthermore, the antibacterial resin composition of this embodiment may be used as a high-concentration product, i.e., a masterbatch. When the antibacterial resin composition of this embodiment is a masterbatch, the total content of antibacterial agents A1, A2, B, and C is preferably 1 to 70 parts by weight per 100 parts by weight of urethane resin. If the total content of antibacterial agents A1, A2, B, and C is less than 1 part by weight, the dilution ratio will be low and not economical when diluted with a resin without antibacterial agents. Also, if the total content of antibacterial agents A1, A2, B, and C exceeds 70 parts by weight, the dissolution or dispersion of each antibacterial agent may be insufficient when diluted with a diluting resin. Furthermore, when the antibacterial resin composition of this embodiment is a masterbatch, the content of each antibacterial agent A1, A2, B, and C is more preferably 1 to 30 parts by weight per 100 parts by weight of urethane resin.

[0036] (Other antibacterial agents) The antibacterial resin composition of this embodiment may also be used with conventional antibacterial agents added. Conventional antibacterial agents are broadly classified into inorganic and organic antibacterial agents. Examples of inorganic antibacterial agents include those on which metal ions such as silver, zinc, and copper are supported, such as zeolite, silica gel, glass, and calcium phosphate, while examples of organic antibacterial agents include alcohol-based, thiazoline-based, and imidazole-based agents. These conventional antibacterial agents may be used individually or in appropriate combinations of two or more.

[0037] (Coloring agent) Since the antibacterial resin composition of this embodiment may require coloring, it may contain a coloring agent as long as it does not hinder the purpose of this disclosure. Examples of coloring agents include organic pigments, inorganic pigments, extender pigments, dyes, etc. These coloring agents may be used individually or in appropriate combinations of two or more.

[0038] (Other additives) Other additives that can be used in this embodiment include flame retardants, ultraviolet absorbers, antioxidants, light stabilizers, antistatic agents, crosslinking agents, and different resins, as long as they do not hinder the purpose of this disclosure. These additives may be used individually or in combination of two or more as appropriate.

[0039] Furthermore, fibrous or plate-shaped fillers such as inorganic, organic, or metallic materials, or powdered or granular fillers, may be added, provided that they do not significantly degrade the performance of the antibacterial resin composition. These may be used individually or in appropriate combinations of two or more types.

[0040] <Method for producing antibacterial resin composition> The method for producing the antibacterial resin composition of this embodiment is not particularly limited, and known equipment and manufacturing methods commonly used for conventional resin composition production can be employed. For example, predetermined amounts of lubricant, each antibacterial agent, and additives added as needed are mixed with a urethane resin and kneaded. The kneading method can be, for example, by using a physical blend such as melt kneading, solvent cast blend, latex blend, or polymer complex. Examples of equipment used for the above kneading include Banbury mixers, kneaders, kneader-ruders, single-screw extruders, and multi-screw extruders. The kneading temperature is not particularly limited, but is usually in the range of 150 to 250°C.

[0041] The antibacterial resin composition of this embodiment can be obtained by molding the composition kneaded as described above using an injection molding machine, extrusion molding machine, blow molding machine, inflation molding machine, compression molding machine, rotational molding machine, or the like.

[0042] <Application> The antibacterial resin composition of this embodiment can be applied to all applications where urethane resin is normally used. Examples include industrial parts (ball joints, rollers, dust covers, gaskets, gears, hammers, grease covers, hoses, tubes, belt conveyors, handrails, etc.), sports and leisure parts (snow chains, sports shoes, ski boots, etc.), various containers (food containers, cosmetic containers, pharmaceutical containers, etc.), automobile parts (vehicle interior parts, etc.), home appliances (air conditioners, jet towels, refrigerators, etc.), electrical equipment parts (switch buttons, etc.), stationery, toys, furniture (clothing storage products, etc.), and daily necessities (kitchenware, bath products, etc.). It can be used particularly suitably in applications where antibacterial properties are considered necessary. Specifically, for example, it is suitable for applications in areas that come into contact with human hands, such as cosmetic containers, pharmaceutical containers, design parts of home appliances, remote controls, switches, switch buttons of electrical equipment parts, handles of stationery such as ballpoint pens, vehicle interior parts of automobiles (inside handles, shift knob buttons, etc.), and escalator handrails. [Examples]

[0043] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0044] <Examples 1-3, Comparative Examples 1-12> (Preparation of simulated antibacterial urethane resin sheets) Each component in the proportions shown in Table 1 was mixed with urethane resin, and the mixture was kneaded at 210°C for 2 minutes using a tabletop small mixer (DSM Xplore MC15). Then, antibacterial urethane resin sheets (hereinafter referred to as "resin sheets") of Examples 1-3 and Comparative Examples 1-12 were manufactured using a tabletop injection molding machine (DSM Xplore IM12). The basic conditions for injection molding were a cylinder temperature of 210°C, a mold temperature of 50°C, and an injection pressure of 7 MPa.

[0045] The components shown in Table 1 are as follows:

[0046] Urethane resin: Thermoplastic polyether urethane (TPU) (BASF, Elastran 1190ATR) Lubricant: Fatty acid amide Antimicrobial agent A1: Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] Antimicrobial agent A2: Dibutylhydroxytoluene Antimicrobial agent B: Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate Antimicrobial agent C: 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol

[0047] <Antibacterial Testing> The following antibacterial tests were performed on each resin sheet of Examples 1-3 and Comparative Examples 1-12 in accordance with JIS Z 2801:2012 (film adhesion method).

[0048] Each of the above antibacterial urethane resin sheets (50 mm x 50 mm) was placed in a sterile petri dish. 0.4 ml of pre-culture solution with adjusted viable cell counts was inoculated onto the sample surface, and the surface was covered with polyethylene film (40 mm x 40 mm). After incubation at 35°C for 24 hours, the bacteria were washed off with SCDLP medium, and the viable cell count was measured by the pour plate method. The results are shown in Table 1. Nutrientpros liquid medium diluted 1 / 20 (Staphylococcus aureus) was used as the nutrient for the inoculum, and compared with the unadded sample, samples with an antibacterial activity value of 2.0 or higher using the JIS-specified calculation formula were judged as "A" (antibacterial) and samples with a value less than 2.0 were judged as "B" (not antibacterial). The unadded sample was the same as the thermoplastic polyether urethane (TPU) described above. Staphylococcus aureus (NBRC 12732) was used as the test strain.

[0049] [Table 1]

[0050] As shown in Table 1, the resin sheets in Examples 1-3 contain all of the antibacterial agents A1, A2, B, and C, and therefore possess antibacterial properties.

[0051] On the other hand, Comparative Example 1 does not have antibacterial properties because no antibacterial agent is added at all. Comparative Examples 2-4, 6, and 7 do not have antibacterial properties because they each contain antibacterial agents A-C individually. Comparative Example 5 has antibacterial properties, but does not contain a lubricant, so it has poor moldability. Comparative Examples 8-11 contain two or three types of each antibacterial agent, but do not contain all of antibacterial agents A1, A2, B, and C, so they do not have antibacterial properties. Comparative Example 12 has a silver-based antibacterial agent added, but does not have antibacterial properties due to the effect of the lubricant.

[0052] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims and not by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included.

Claims

1. It contains a urethane resin, a lubricant, and antibacterial agents including a hindered phenol derivative, a hindered amine derivative, and a benzotriazole derivative. An antimicrobial resin composition in which the hindered phenol derivatives are pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and dibutylhydroxytoluene.

2. The antimicrobial resin composition according to claim 1, wherein the hindered amine derivative is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

3. The antimicrobial resin composition according to claim 1 or claim 2, wherein the benzotriazole derivative is 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol.

4. The antibacterial resin composition according to claim 1 or claim 2, wherein the urethane resin comprises at least one selected from the group consisting of ether-based urethane resins, ester-based urethane resins, and carbonate-based thermoplastic urethane resins.

5. The antimicrobial resin composition according to claim 1 or claim 2, wherein the lubricant is a fatty acid amide.

6. The antibacterial resin composition according to claim 1 or claim 2, comprising 0.05 to 20 parts by weight of the lubricant and 0.2 to 20 parts by weight of the antibacterial agent per 100 parts by weight of the urethane resin.

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