JP4816224B2 - Standard test piece for antibacterial test, manufacturing method thereof, and antibacterial test method - Google Patents

Description

  The present invention relates to a standard test piece that exhibits antibacterial activity for antibacterial tests with a certain effect, a method for producing the same, and an antibacterial test method.

  In recent years, so-called “antibacterial processed products” such as antibacterial paints, antibacterial films and sheets, antibacterial toiletries, antibacterial kitchen utensils, and antibacterial electrical products have become widespread in the demand for a more comfortable living environment. Yes. The antibacterial processed product is obtained by applying antibacterial processing to a substrate made of plastic, metal, ceramics, paint, or the like in order to suppress bacterial growth on the product surface. For antibacterial processing, inorganic antibacterial agents containing metals such as silver, copper and zinc, natural antibacterial agents such as hinokitiol and chitosan, and antibacterial agents such as organic antibacterial agents such as pyridine and imidazole are used. ing.

  As a standard for evaluating the antibacterial effect of these antibacterial processed products, in Japan, in accordance with the antibacterial product guidelines announced by the Ministry of Economy, Trade and Industry (formerly the Ministry of International Trade and Industry) Life-related new functional processed product round-table conference, Antibacterial processed product-Antibacterial test method / antibacterial effect ”is specified. In this standard, Staphylococcus aureus and Escherichia coli are inoculated into antibacterial processed products and unprocessed products, and after culturing them, the difference in the logarithmic value of the number of each viable cell is the antibacterial activity value. It is a standard for evaluating the antibacterial effect of antibacterial processed products based on this antibacterial activity value.

  In addition, antibacterial tests were added to the accreditation category in the testing company accreditation system (JNLA) based on the Industrial Standardization Act, and laboratory accreditation in this field was started.

  Antibacterial processed products are beginning to spread widely not only in Japan but also in Asia and Europe and America. Under such circumstances, standards for antibacterial processed products are required to be stepped up from national standards (JIS Z 2801: 2000) to international standards (ISO standards), and ISO standardization is actually being promoted. If you can build a system (One-Stop-Testing) that can accept data obtained from reliable laboratories that meet international standards in the international market all over the world, antibacterial processed products at home and abroad Significance in the market is enormous.

  For this purpose, a standard test piece for a stable antibacterial test capable of expressing a certain antibacterial activity value is indispensable for a testing institution having a certain technical level.

  Patent Document 1 describes a standard test piece for antibacterial test. This standard test piece for antibacterial test is a standard test piece for antibacterial test formed by forming an antibacterial water soluble resin layer containing a water soluble resin and a water soluble antibacterial agent on a plastic film. When the antibacterial test of JIS Z 2801 is conducted using this standard test piece for antibacterial test, if all the water-soluble resin and water-soluble antibacterial agent are dissolved in the test bacterial solution, all antibacterial components contribute to the antibacterial action. Therefore, it is considered that the antibacterial effect can be evaluated accurately and with high reproducibility.

  However, in reality, since the water-soluble resin does not necessarily dissolve uniformly in the bacterial solution, there is a problem that some antibacterial components remain held in the water-soluble resin, which leads to variations in the antibacterial effect.

In Patent Document 2, a first binding layer is formed on a substrate surface, specifically bound to the first compound, and a second binding composed of a second compound in which each molecule can hold a certain amount of antibacterial component. An antibacterial test standard piece comprising a layer and the antibacterial component held in an exposed state for each molecule of the second compound is shown in claim 1. Furthermore, claim 2 shows that the substrate has a hydrophobic surface, the first compound is a sterol, and the second compound is a sterol-binding protein.
In the present invention, sterol-binding protein binds on sterol to form a layer of protein, and is considered to be arranged in a constant amount per unit area. However, it is not confirmed that an accurate and high reproducibility can be obtained. The antibacterial test standard piece has a problem that it is expensive and difficult to mass-produce because it uses so-called biotechnology.

JP 2002-95497 A JP 2006-14709 A

  This invention is made | formed in view of the conventional situation, Comprising: It aims at providing the standard test piece and test method for antimicrobial test which can express an antimicrobial effect correctly and with sufficient reproducibility.

As a result of intensive studies, the inventor kneaded an inorganic antibacterial agent into a resin and molded it, and then used the one obtained by removing the surface of the molded product, thereby accurately and reproducibly in the antibacterial test. The inventors have found that the antibacterial effect can be expressed well and have completed the present invention. That is, the present invention
(1) A standard test piece for an antibacterial test characterized by performing surface peeling treatment of a molded product in which an inorganic antibacterial agent is kneaded into a resin,
(2) The antibacterial test standard test piece according to (1), wherein the inorganic antibacterial agent is an inorganic antibacterial agent containing silver,
(3) The antibacterial test standard test piece according to the above (2), wherein the silver-containing inorganic antibacterial agent is silver-supported zirconium phosphate.
(4) Any one of the above (1) to (3), wherein the resin is one or more selected from polyethylene, polypropylene, vinyl chloride, ABS resin, nylon, polyester, polystyrene, polyacetal, and polycarbonate. Standard test piece for antibacterial test
(5) The standard test piece for antibacterial test according to any one of (1) to (4), wherein the surface of the molded product is peeled off by 0.1 to 500 μm,
(6) The standard test for antibacterial test according to (5), wherein the method of surface peeling treatment of the molded article is one or more selected from sandpaper peeling, buff peeling, sandblast peeling, and surface cutting peeling. Is a piece,
(7) A method for producing a standard test piece for an antibacterial test characterized in that an inorganic antibacterial agent is kneaded into a resin and molded, and then the surface of the molded product is subjected to surface peeling treatment.
(8) A method for performing an antibacterial test using the antibacterial test standard test piece according to any one of (1) to (6).

  The standard test piece for antibacterial test of the present invention can exhibit an antibacterial effect accurately and reproducibly in the antibacterial test. Moreover, it is inexpensive and easy to manufacture. Therefore, the antibacterial test standard specimen of the present invention is useful as an antibacterial test standard in the test company certification system and as a standard test piece for antibacterial tests toward the establishment of international standards for antibacterial tests. is there.

Hereinafter, the present invention will be described in detail.
In the present invention, since the antibacterial agent is kneaded into the resin and molded, the antibacterial agent is required to have heat resistance. Therefore, an inorganic antibacterial agent is used in the present invention. As the inorganic antibacterial agent, those containing an antibacterial metal such as silver, copper and zinc are known, but those containing silver having high antibacterial performance and high safety are preferable. Examples of silver-containing inorganic antibacterial agents include silver-supported zeolite, silver-supported zirconium phosphate, silver-supported calcium silicate, silver-supported titanium oxide, silver-containing hydroxyapatite, silver-containing calcium phosphate, and silver-containing glass. Zeolite, silver-supported zirconium phosphate, silver-supported calcium silicate, and silver-containing calcium phosphate are preferred, and silver-supported zirconium phosphate is particularly preferred. Silver-supported zirconium phosphate has the characteristics of low hygroscopicity, uniform particle size, and high heat resistance, so it is most suitable as an antibacterial agent used in this application. From Toagosei Co., Ltd. Sold under the trade name.

  The resin used in the present invention is not particularly limited, and may be any of natural resin, semi-synthetic resin, and synthetic resin. Specific resins include polyethylene, polypropylene, vinyl chloride, ABS resin, nylon, polyester, polyvinylidene chloride, polyamide, polystyrene, polyacetal, polycarbonate, acrylic resin, fluorine resin, polyurethane elastomer, polyester elastomer, melamine resin, urea resin. , Plastics such as ethylene tetrafluoride resin, unsaturated polyester resin, epoxy resin, urethane resin and phenol resin. Among these, a thermoplastic resin is preferable from the viewpoint of easy molding, and polyethylene, polypropylene, vinyl chloride, ABS resin, nylon, polyester, polystyrene, polyacetal, and polycarbonate are particularly preferable.

  In the present invention, the amount of the inorganic antibacterial agent for kneading the resin into the resin is preferably 0.05 to 3% by weight, more preferably 0.1 to 2% by weight. Within this range, the antibacterial activity is stably expressed, which is preferable.

  By removing the surface of the molded product, the standard test piece for antibacterial test of the present invention can be obtained. The peeling treatment is to peel the surface of the molded product with a thickness of 0.1 to 500 μm, and preferably with a thickness of 0.3 to 300 μm.

  Examples of the surface peeling treatment method include sandpaper peeling, buff peeling, grinding, sandblasting, surface cutting, and laser processing. Of these, sandpaper polishing, buffing, sandblasting, and / or surface cutting are preferred in the present invention. In addition, the sandpaper here also includes a fine polishing film called a wrapping film, in addition to what is usually sold as sandpaper.

Hereinafter, the meaning and mechanism of the surface peeling treatment will be described in detail.
When an inorganic antibacterial agent is kneaded into a resin and molded, the surface of the molded product is in a special state. That is, the surface of the inorganic antibacterial agent present in the vicinity of the resin surface is often covered with a thin resin layer. This thin resin layer cannot be confirmed by simply performing observation with a scanning electron microscope, but it can be confirmed by changing the acceleration voltage. In the scanning electron microscope observation, highly accelerated electrons reach not only the resin surface but also the inside of the resin, so that the inorganic antibacterial agent present inside the resin is also visually recognized. Since the reaching distance to the inside of the resin becomes longer as the acceleration voltage of electrons increases, for example, the inorganic antibacterial agent is visually recognized when observed at an acceleration voltage of 15 kV, and the inorganic antibacterial agent is not observed when observed at 5 kV. It can be confirmed that the agent is not cueed on the resin surface, that is, the surface of the inorganic antibacterial agent is covered with a thin resin layer.

  In order for a molded product in which an inorganic antibacterial agent is kneaded into a resin to exhibit antibacterial performance, it is necessary that the inorganic antibacterial agent is cued from the surface of the molded product. However, since the surface of the molded product is in a special state as described above, even if molding is performed under the same conditions, a slight difference in conditions at that time, that is, a slight difference in water content, a slight molding machine temperature, It is difficult to produce a molded product that exhibits stable antibacterial performance due to differences in resin lots and the like.

  However, if the antibacterial agent is kneaded uniformly, the inside is uniform, and if the thin resin layer on the surface of the molded product is eliminated, stable antibacterial performance can be expressed. In JIS Z 2801, since a 50 mm square test piece is usually used, uniformity in a microscopic region is not necessary, and it is only necessary to be uniform at an area level of 50 mm square.

The size of the abrasive grain of the sandpaper used for the sandpaper peeling of the present invention is not particularly limited, but # 500 to # 10,000 is preferable, more preferably # 800 to 5,000, and further preferably # 1,000. ~ 3,000. This sandpaper peeling method may hold the sandpaper in the hand and polish it a predetermined number of times, but in order to reduce variation due to the polishing work, the sandpaper is fixed to a polishing machine and rotated at a constant speed, In addition, a method of pressing the resin piece to be polished with a constant load for a predetermined time is preferable.
Although it is the degree of sandpaper peeling, it is only necessary to eliminate the thin resin layer on the surface of the molded product, but since the optimum conditions of the prepared test pieces are different, if the optimum sand paper peeling conditions are selected for each test piece, Good.
As long as the surface of the molded product can be peeled at the above-mentioned thickness, any abrasive grain of the sandpaper used for the peeling treatment may be used. For example, it can be carried out by performing a peeling operation 3 to 50 times with a weight of 1 to 30 kg on a 25 cm ² molded article using a sandpaper of # 1000.

The buff peeling is a method in which the surface of a metal product or a resin product is peeled off with a polishing cloth called buff. As a buffing method, a fixed buffing machine is used for buffing the object to be polished in hand, a buffing machine is held in the hand and the object to be buffed is peeled off, or continuously. For example, a formula buff peeling method may be used. Among these, the continuous buff peeling method is preferable in order to reduce variation due to the buff peeling work.
Although it is the degree of buff peeling, it is only necessary to eliminate the surface of the molded product with the thickness described above, but since the optimum conditions for the prepared test pieces are different, it is only necessary to select the optimum buff peeling conditions for each test piece. .

Grinding is a method of peeling the surface using a grindstone such as a grinder. Examples of the grinding method include a method of grinding a molded product by holding it against a fixed buffing machine, a method of grinding a molded product by holding a grinding machine in hand, and the like.
Although it is the degree of grinding, it is only necessary to eliminate the surface of the molded product with the thickness described above. However, since the optimum conditions of the prepared specimens are different, it is only necessary to select the optimum grinding conditions for each specimen. .

Sand blasting is a method of performing a peeling process by spraying abrasive grains onto a molded product at a high speed. As a sandblasting method, a fixed sandblasting machine is used to carry out sandblasting with a molded product in hand, a method for sandblasting a molded product with a sandblasting machine in hand, or continuous sandblasting. Methods and the like. Of these, a continuous sandblasting method is preferred in order to reduce variation due to sandblasting operations.
Although it is the degree of sandblasting, it is only necessary to eliminate the surface of the molded product with the thickness described above, but since the optimum conditions of the prepared test pieces are different, it is only necessary to select the optimum sandblasting conditions for each test piece .

  Surface cutting is a method of cutting the surface of a molded product with a constant thickness or by setting a thickness after cutting. Any thickness may be used as long as the surface of the molded product can be eliminated with the thickness described above.

  The laser processing method is a method of peeling the surface by scanning the surface of the molded product with a laser. Lasers range from weak to powerful enough to penetrate the molded product instantaneously. For the purpose of eliminating a thin resin layer on the molded product surface, a laser of about 1 to 5 W is preferable.

  Among these methods, in the method using an abrasive and an abrasive, the abrasive and the abrasive may remain on the surface after the surface of the molded product is peeled off. If these have no antibacterial performance, they will not affect the standard test pieces for antibacterial testing, but if they affect the antibacterial performance to some extent, they will cause variation. Moreover, if the inorganic antibacterial agent kneaded into the molded product is detached after the surface peeling treatment of the molded product and remains on the surface, it causes variation. Therefore, it is necessary to reliably remove the remaining abrasive grains, abrasive, and inorganic antibacterial agent particles completely detached from the molded product. Examples of the method include wiping the surface with a liquid such as air blow or alcohol, washing in a liquid such as alcohol, or ultrasonic cleaning in a liquid such as alcohol, and the like.

According to JIS Z 2801, regarding the “antibacterial effect”, “the antibacterial effect of the antibacterial processed product has an antibacterial activity value obtained by the test method of this standard of 2.0 or more. A numerical value exceeding 2.0 may be used. " Therefore,
The set value of the antibacterial activity value as the standard test piece for the antibacterial test is preferably 2 or more and 3 or less.

  In addition, in the explanation of the same JIS, there is a description that “in general, there is a possibility that a one-digit difference (1 in logarithmic value) may occur in counting the number of bacteria on an agar plate medium”. is there. Therefore, it is desirable that the standard deviation of the repetition error of the antibacterial activity value is about 0.5 or less as the standard test piece for the antibacterial test.

<Example>
Hereinafter, the present invention will be described more specifically, but the present invention is not limited thereto. In addition,% is weight%.

A low density polyethylene (LDPE) resin masterbatch containing 10% of silver-supported zirconium phosphate (Novalon AG300 manufactured by Toagosei Co., Ltd.) was prepared.
Using this masterbatch and polypropylene (PP) resin as the dilution resin, an inorganic antibacterial agent is used in the injection molding machine so that the content of the inorganic antibacterial agent is 0.15, 0.20, and 0.25%. An agent-containing test piece was prepared. The size of the test piece is 50 mm × 50 mm × 2 mm.
The surface of the test piece was peeled 10 times each in the vertical and horizontal directions with # 1,000 sandpaper, and then air blown to remove the peeled piece.
The above operation was performed three times on different days (referred to as A, B, and C).
An antibacterial test was conducted according to JIS Z 2801, and the results are shown in Table 1 (hereinafter, the antibacterial test is based on JIS Z 2801).
Moreover, the antibacterial property test was similarly implemented about what was not sandpaper peeling-processed, and it was set as the comparative example. The results are shown in Table 1.

An LDPE resin master batch containing 10% of a silver-supporting zeolite (Fuji Chemical Co., Ltd., Bactekiller BM-502FC) was prepared.
Using this masterbatch and LDPE resin as the dilution resin, the inorganic antibacterial agent content is 1.0, 1.2, 1.4, and 1.8% with an injection molding machine. An antibacterial agent-containing test piece was prepared. The size of the test piece is 50 mm × 50 mm × 2 mm.
The surface of the test piece was peeled 10 times each in the vertical and horizontal directions with # 1000 sandpaper, then air blown to remove the peeled piece, and an antibacterial test was conducted. The results are shown in Table 2.

A PP resin test piece was prepared in the same manner as in Example 1, subjected to sandblast peeling treatment under the following conditions, and the peeled surface was wiped with ethanol.
On another day, a PP resin test piece was prepared in the same manner as in Example 1, and the sandblast peeling treatment was performed under the same conditions. The test piece was immersed in ethanol and subjected to ultrasonic cleaning for 1 minute to remove the peeled piece. These test pieces were subjected to antibacterial tests, and the results are shown in Table 3.
○ Sandblast peeling conditions 1) Abrasive grains (White Alandom) # 220
2) Injection pressure 0.35 MPa
3) Processing time 10 seconds

  A PP resin test piece was prepared in the same manner as in Example 1, and a buff peeling treatment was performed. The state where the entire surface was peeled uniformly by visual observation was defined as the end point. The test piece was immersed in ethanol and subjected to ultrasonic cleaning for 1 minute to remove the peeled piece. An antibacterial test of these test pieces was performed. The results are shown in Table 4.

  A PP resin test piece was produced in the same manner as in Example 1 (inorganic antibacterial agent addition amount was 2.0%), and surface cutting was performed so that the thickness after cutting was 1.8 mm. The test piece was immersed in ethanol and subjected to ultrasonic cleaning for 1 minute to remove the peeled piece. Antibacterial tests of these test pieces were conducted at three different test institutions. The results are shown in Table 5.

  The standard test piece for antibacterial test of the present invention can exhibit antibacterial activity with good reproducibility, so it can be used as a standard for antibacterial test in the testing company certification system, and antibacterial for the establishment of international standards for antibacterial tests. It can be used as a standard test piece for sex testing.

Claims (8)

  A standard test piece for antibacterial test characterized by performing surface peeling treatment of a molded product in which an inorganic antibacterial agent is kneaded into a resin.   The standard test piece for antibacterial test according to claim 1, wherein the inorganic antibacterial agent is an inorganic antibacterial agent containing silver.   The standard test piece for antibacterial test according to claim 2, wherein the silver-containing inorganic antibacterial agent is silver-supported zirconium phosphate.   The antibacterial test standard according to any one of claims 1 to 3, wherein the resin is one or more selected from polyethylene, polypropylene, vinyl chloride, ABS resin, nylon, polyester, polystyrene, polyacetal, and polycarbonate. Test pieces.   The standard test piece for antibacterial tests according to any one of claims 1 to 4, wherein the surface of the molded article is peeled off by 0.1 to 500 µm.   The standard test piece for an antibacterial test according to claim 5, wherein the method of surface peeling treatment of the molded product is one or more selected from sandpaper peeling, buff peeling, sandblast peeling, and surface cutting peeling.   A method for producing a standard test piece for antibacterial test, which comprises kneading an inorganic antibacterial agent into a resin and molding the resin, and then performing a surface peeling treatment on the molded product.   A method for performing an antibacterial test using the standard test piece for an antibacterial test according to any one of claims 1 to 6.