JP6695558B1 - Antibacterial surface treatment method and antibacterial member - Google Patents

Abstract

An antibacterial surface treatment method capable of imparting an antibacterial (or sterilization, sterilization) effect to the surface of a member by forming numerous dimple-shaped minute recesses on the surface of the member, and an antibacterial (or sterilization, sterilization) ) An antibacterial member having an effect is provided. An antibacterial surface treatment method according to the present invention is characterized by imparting an antibacterial action to the surface of a member by forming numerous dimple-shaped minute recesses on the surface of the member. Further, the antibacterial member according to the present invention is characterized in that the surface of the member is provided with an antibacterial action by forming innumerable dimple-shaped minute concave portions on the surface of the member. [Selection diagram] Figure 1

Description

  TECHNICAL FIELD The present invention relates to a technique of imparting an antibacterial action or a bacterium growth suppressing action (an antibacterial effect or a bacterium growth suppressing effect) to a member surface by performing a treatment for forming a myriad of minute recesses on a member.

  Conventionally, edible powders such as wheat flour, corn starch, potato starch, matcha powder, cocoa powder, powdered sugar and curry powder, and powders such as pharmaceutical powders (powdered medicines) have been classified (or classified) by screening. , Handling containers such as hoppers and transport parts such as shooters and conveyors.

  These powders grow on the surface of members such as sieves, storage containers and transport parts, and grow into relatively large lumps, leading to defective discharge (hopper) and clogging (flue). However, this is one of the causes of a decrease in production efficiency and an increase in defective products.

  Therefore, the inventors of the present invention repeated various studies and experiments, and based on the results, the applicant of the present application, in Patent Document 2, performed fine particle peening treatment (WPC treatment) to obtain powder. A technique has been proposed in which the adhesion of powder can be suppressed by forming a plurality of minute recesses (minute dimples) on the surface of a member that contacts the body (hereinafter, also referred to as a powder contact member).

JP-A 06-273318 Patent No. 6416151

  Here, in order to explore the possibility of applying the surface modification technique by forming dimple-shaped fine irregularities to various fields, the applicant of the present application has proposed that Various approaches have been taken, such as confirming the action and effect of forming innumerable minute irregularities on the surface in various fields, and in the process, the inventors of the present invention have obtained new findings that were not known until now. Obtained.

  Heretofore, the effects that have been known as the effects of forming a plurality (innumerable) of dimple-shaped minute recesses are the suppression of adhesion of powder or sticky substances, and the formation of innumerable minute unevenness in the sliding portion. By doing so, it functions as an oil reservoir to reduce sliding resistance and suppress wear, and the effect discovered this time is a completely different effect that cannot be predicted from these.

  The knowledge is that an infinite number (a plurality) of dimple-shaped minute concave portions are randomly formed on the surface of the member, and an antibacterial (or sterilization or sterilization) effect can be produced.

  The present invention has been made in view of the above-mentioned circumstances, and has a plurality of (innumerable) dimple-shaped minute recesses on the surface of the member to have an antibacterial (or sterilization, sterilization) effect on the surface of the member. It is an object of the present invention to provide an antibacterial surface treatment method which can be applied, and an antibacterial member having an antibacterial (or sterilization) effect.

Therefore, the antibacterial surface treatment method according to the present invention,
There are countless dimple-shaped minute recesses on the surface of the member that come into contact with bacteria, the maximum value of the uneven pitch is 7.3 μm or less and the minimum value is 0.4 μm or more, and the maximum depth of the recesses is It is characterized in that the surface of the member is given an antibacterial effect by forming minute recesses having a value of 1.0 μm or less and a minimum value of 0.04 μm or more by a projection process of projecting a shot material.

Further, the antibacterial member according to the present invention,
A de Inpuru like minute recess formed in innumerable by a projection process of projecting shots, the minimum value is less than or equal to the maximum value of the unevenness pitch 7.3μm is at 0.4μm or more, the depth of the recess in Rukoto comprising a surface in contact with the bacteria member having fine recesses is and minimum 0.04μm or more in the 1.0μm or less the maximum value of the, that gave an antimicrobial effect on the surface of the member Characterize.

  According to the present invention, by forming a plurality (innumerable) of dimple-shaped minute recesses on the surface of a member, an antibacterial surface treatment method capable of imparting an antibacterial (or sterilization, sterilization) effect to the surface of the member, and An antibacterial member having an antibacterial (or sterilization or sterilization) effect can be provided.

7 is a list showing antibacterial properties (presence / absence of antibacterial effect) due to different treatment contents for forming innumerable dimple-shaped minute recesses on the surface of the member according to the embodiment of the present invention. It is a figure which shows the 3D image and surface roughness of the surface of the sample (1) which used for the antibacterial test which concerns on embodiment same as the above. It is a figure which shows the 3D image and surface roughness of the surface of the sample (2) which used for the antibacterial test which concerns on embodiment same as the above. It is a figure which shows the 3D image and surface roughness of the surface of the sample (3) which used for the antibacterial test which concerns on embodiment same as the above. It is a figure which shows the 3D image and surface roughness of the surface of the sample (4) which used for the antibacterial test which concerns on embodiment same as the above. (A) is a list showing the average unevenness pitch (spacing of the convex portions) and the antibacterial activity value (antibacterial effect) of the samples (1) to (5) used for the same antibacterial test sample, and (B) is the horizontal axis. Is the average unevenness pitch (space between convexes), and the vertical axis shows the antibacterial activity value (R). (A) is a figure which shows an example of the measurement data (surface shape data) of the uneven pitch (interval of convex parts) of sample (2), and (B) is the uneven pitch (interval of convex parts) of sample (3). It is a figure which shows an example of the measurement data (surface shape data) of. (A) is a figure which shows an example of the measurement data (surface shape data) of the uneven pitch (interval of convex parts) of the sample (4), and (B) is the uneven pitch (interval of convex parts) of the sample (5). It is a figure which shows an example of the measurement data (surface shape data) of. It is a list which shows an example of the measured recessed part (convex part) pitch, measured recessed part depth, and surface roughness of the samples (2)-(5) used for the same antibacterial test sample. It is a list which shows the pitch of a minute recessed part (convex part) of a sample (1), (3), and (4) which provided the same antibacterial test sample, a depth, and a microbial propagation test result (antibacterial test result). It is a list showing the shot material particle size, the antibacterial activity value, and the antibacterial effect when the samples (1) to (5) used as the same antibacterial test sample are surface-treated.

  Hereinafter, an embodiment according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described below.

  As described above, the applicants of the present application have contacted with the object to be processed in order to explore the possibility of applying the surface modification technique by forming the dimples (dents, substantially concave spherical surfaces) to various fields. Various approaches have been taken in various fields to confirm the action and effect of forming innumerable minute recesses on the surface of a member to be treated (contact member to be treated). In the process of such an approach, the present inventors Obtained new knowledge that was not previously known.

  In addition, in the present embodiment, the member is a member (contact target contact member) with which the processing target contacts (for example, storage, storage, transportation, sliding, sieving, stirring equipment, cooking bowl, cooking equipment, surgical equipment). The present invention is not limited to members that come into contact with objects to be subjected to various treatments including medical instruments and the like), and can be applied to members that have antibacterial properties (antibacterial members).

Specifically, in the process of the approach, a member (test piece) in which dimple-shaped minute recesses were formed innumerably on the surface was subjected to an antibacterial activity evaluation test (Japanese Industrial Standard JIS Z 2801: 2010), It was found that a member (sample or test piece) having innumerable minute recesses formed on its surface has a high antibacterial action (or sterilizing action, sterilizing action).
This finding is a function and effect which has not been heretofore known with respect to a member in which numerous dimple-shaped minute recesses are formed on the surface, and as described above, it is a function and effect which cannot be predicted from the findings so far.

The test was conducted at the Kanagawa Prefectural Industrial Technology Research Institute.
As a test method, an antibacterial activity evaluation test by a film adhesion method was performed on samples (test pieces) having different surface treatments (surface textures).

The test conditions are as shown below.
Test strain: Escherichia coli NBRC3972 strain Inoculum concentration: 3.3 × 10 ⁵ CFU / mL
Bacterial fluid inoculum: 0.4mL
Test area: 40 × 40 mm square Covering film: Esculinica pack L, manufactured by Sekisui Chemical Co., Ltd. Test temperature: 35 ° C.
Test time: 8 hours
A microbial medium sheet for coliforms (manufactured by JNC Co.) was used for measuring the viable cell count.
The viable cell count was measured by washing the sample with 9.6 mL of sterile physiological saline and measuring the viable cell count concentration in the washed-out solution.

As a result, as shown in FIG. 1, the sample (1) “SUS304 # 400 untreated” was No. 1-No. In the lot of No. ³ , the viable cell count concentration of E. coli (CFU / mL) is in the range of 4.0 × 10 ^{3 to} 1.7 × 10 ⁴ . In addition, "SUS304 # 400 untreated" is a stainless steel plate made of SUS304 whose surface is polished and finished with a P400 buff, and the surface has a gloss close to a mirror surface, as shown in FIG. Streak-like grooves are observed. For reference, the surface has a surface roughness Ra = 0.031 μm and a surface roughness Rz = 0.364 μm. The pitch of the streaks (streak grooves) is about 0.4 to 0.8 μm, and the depth is about 0.05 μm, although they are not dimple-shaped minute recesses.
Samples (2) to (5) described later are obtained by subjecting this sample (1) to various surface treatments.

  In addition, the measurement values of the 3D image, the surface roughness Ra, and the surface roughness Rz in the present embodiment, including those described below, are based on the actual surface property measurement data, and the shape measurement laser manufactured by KEYENCE Co., Ltd. It was acquired using a microscope VK-X100.

The sample (2) “SUS304 # 400 MW” had No. 3 as shown in FIG. 4 to No. In the lot of No. 6, the viable cell count concentration (CFU / mL) of E. coli was in the range of 3.7 × 10 ^{1 to} 4.0 × 10 ² , which was lower than that of sample (1). Against antibacterial effect).
In addition, "SUS304 # 400 MW" is obtained by subjecting the sample (1) to a surface treatment (microdimple treatment) for forming a dimple-shaped minute concave portion, and the surface of a stainless steel plate material made of SUS304 is ( A polishing medium FGB (Fuji glass beads) manufactured by Fuji Manufacturing Co., Ltd. with a medium (shot material) having a particle number 400 (center particle diameter is ≤53 μm) together with compressed air of about 1 / number (for example 0.3) MPa. Projection processing (projection processing) for projecting is performed. The fine concavo-convex forming process (micro dimple process) for performing such projection processing is referred to as MW here.
In addition, as shown in FIG. 3, innumerable relatively large dimple-shaped concave portions are randomly formed on the surface after this treatment. For reference, the surface has a surface roughness Ra = 0.263 μm and a surface roughness Rz = 2.285 μm.

  The sample (3) "SUS304 # 400 P43" was tested as No. 3 as shown in FIG. 7-No. In the 9 lots, the viable cell count concentration (CFU / mL) of E. coli is all less than 1 (<1), and E. coli is sterilized or sterilized.

The sample (3) "SUS304 # 400 P43" was obtained by subjecting the sample (1) to a surface treatment (microdimple treatment) for forming dimple-shaped minute recesses. Eye media (brand name "Fuji Random (Carborundum)", grain number C # 400 (maximum particle diameter 75 μm or less, particle diameter at cumulative height 50% point 30.0 ± 2.0 μm) SiC (silicon carbide) ) Is jetted from the jet nozzle together with compressed air of about 1 / several (for example, 0.3) MPa, and projection processing (hereinafter also referred to as projection processing) is performed on the surface to be processed (the surface of the sample, the surface of the member).
Next, for example, the second type of media (trade name "Fuji Random (Carborundum)", grain number C # 3000 (maximum particle diameter 13 μm or less, particle diameter at cumulative height 50% point 4.0 ± 0.5 μm) ) SiC (silicon carbide)) was subjected to projection processing (projection processing) on the surface to be processed together with compressed air of about 1 / s (for example, 0.4) MPa.
The fine concavo-convex forming process (micro dimple process) in which the above-described media having different specifications are divided into two stages and subjected to the projection process is referred to as P43 here.
As shown in FIG. 4, the sample (3) has an infinite number of dimple-shaped minute recesses formed randomly on the surface. For reference, the surface has a surface roughness Ra = 0.252 μm and a surface roughness Rz = 3.238 μm.

  Here, conventionally, in the projection processing in which a fine-grained medium (shot material) is projected to form dimple-shaped minute recesses, a surface roughness Ra = 0.252 μm and a surface roughness Rz = 3.238 μm It is difficult to form recesses (roughness pitch (distance between adjacent protrusions) of the sample (3) in the range of about 1.7 to 7.3 μm and recessed depth range of about 0.2 to 1.0 μm). However, through experiments and research conducted by the present inventors, media (shot materials) having different specifications are divided into two stages and projection processing is performed, so that very small dimple-shaped concave portions are formed even in stainless materials. It became possible to form innumerable randomly.

  The sample (4) "SUS304 # 400 PT1" had No. 3 as shown in FIG. 10-No. In the 12 lots, like the sample (3), the viable cell count concentration (CFU / mL) of Escherichia coli was all less than 1 (<1), and Escherichia coli was sterilized or sterilized.

The sample (4) “SUS304 # 400 PT1” was obtained by subjecting the sample (1) to a surface treatment (microdimple treatment) for forming dimple-shaped minute recesses. Tungsten carbide powder manufactured by Co., Ltd., symbol WC-10 (particle size: 0.70 to 1.19 μm) is jetted from a jet nozzle together with compressed air of about 1 / number (for example, 0.4) MPa, and a surface to be processed The projection processing was performed on.
The minute concavo-convex forming process (micro-dimple process) for performing such projection processing is referred to as PT1 here.
As shown in FIG. 5, the sample (4) has a large number of dimple-shaped minute recesses formed randomly on the surface. For reference, the surface has a surface roughness Ra = 0.042 μm and a surface roughness Rz = 0.689 μm.

  Here, conventionally, in the projection processing in which a fine-grained medium (shot material) is projected to form a dimple-shaped minute concave portion, a surface roughness Ra of 0.042 μm and a surface roughness Rz of about 0.689 μm are used. It is possible to form recesses (roughness pitch (distance between adjacent protrusions) of the sample (4) is approximately 0.4 to 1.0 μm, and depth of recesses is approximately 0.04 to 0.17 μm). However, through experiments and research conducted by the present inventors, by using a medium (shot material) having a large specific gravity of about tungsten carbide or more, a myriad of very small dimple-shaped minute recesses can be formed even on stainless steel materials. It can now be formed randomly.

As shown in FIG. 1, the sample (5) “SUS304 # 400 WS” had No. 13-No. In 15 lots, the viable cell count concentration (CFU / mL) of E. coli was in the range of 1.0 × 10 ^{2 to} 8.9 × 10 ² , which was lower than that of sample (1) (in E. coli). Against antibacterial effect).
The “SUS304 # 400 WS” is obtained by subjecting the sample (1) to a surface treatment (microdimple treatment) for forming dimple-shaped minute recesses, and specifically, a general product manufactured by IKK Shot Co., Ltd. A shot (steel shot) TSH-60 for for blasting is projected at a projection pressure of 1 / number (for example, about 0.04) MPa, and then # 2000 diamond powder is projected at a pressure of 1 / number (for example, 0). A process of projecting at MPa was applied.
As the # 20000 diamond powder, for example, a medium for polishing abrasive grains, that is, an elastic body (so-called rubber) as a carrier, in which diamond with a particle size of 0.5 to 1.0 μm is kneaded, is processed. It is possible to use a medium in which the rubber, which is an elastic body, is deformed when jetted toward the surface and collided, so that the hard diamond powder can sink into the surface of the mating material to form a fine recess.
The fine concavo-convex forming process (micro dimple process) for performing such projection processing is referred to as WS here.

Sample (6) “SUS304 # 700 untreated” (conventional product) was No. 16-No. In the 18 lots, the viable cell count concentration (CFU / mL) of E. coli was in the range of 5.1 × 10 ^{3 to} 9.1 × 10 ³ , which was similar to that of the sample (1). Is becoming
In addition, "SUS304 # 700 untreated" is a stainless steel plate made of SUS304 whose surface is polished and finished with a P700 buff, and the surface is a quasi-mirror finish with a high reflectance (streak-like). Some polishing eyes remain).
Samples (7) to (10) described below are obtained by subjecting this sample (6) to various surface treatments.

The sample (7) “SUS304 # 700 MW” had No. 3 as shown in FIG. 19-No. In the 21 lots, the viable cell count concentration (CFU / mL) of E. coli was in the range of 3.2 × 10 ^{2 to} 3.7 × 10 ² , which was lower than that of sample (1) and sample (6). (It has an antibacterial effect against Escherichia coli).
The sample (7) “SUS304 # 700 MW” is a sample obtained by subjecting the sample (6) to the MW treatment.

The sample (8) “SUS304 # 700 P43” was tested as No. 2 as shown in FIG. 22-No. In the 24 lots, the viable cell count concentration (CFU / mL) of E. coli is in the range of less than 1 (<1) to 1.5 × 10 ² , and E. coli is sterilized or sterilized.
The sample (8) “SUS304 # 700 P43” is the sample (6) which has been subjected to the fine concavo-convex forming process (microdimple process) of the P43 process.

Sample (9) “SUS304 # 700 PT1” was No. 25-No. In 27 lots, the viable cell count concentration (CFU / mL) of E. coli is in the range of less than 1 (<1) to 1.8 × 10 ¹ , and E. coli is sterilized or sterilized.
The sample (9) "SUS304 # 700 PT1" is a sample obtained by subjecting the sample (6) to the micro unevenness forming process (microdimple process) of the PT1.

The sample (10) “SUS304 # 700 WS” is No. 13-No. In 15 lots, the viable cell count concentration (CFU / mL) of E. coli is in the range of 9.1 × 10 ^{1 to} 2.4 × 10 ² , which is lower than that of the sample (1). Against antibacterial effect).
The sample (10) "SUS304 # 700 WS" is a sample obtained by subjecting the sample (6) to the WS treatment.

Here, when the above experimental results are summarized, the characteristics shown in FIG. 6 were obtained.
The table shown in FIG. 6 (A) shows the average uneven pitch (spacing between adjacent convex portions) (μm) and the antibacterial activity value of a sample (test piece) obtained by subjecting SUS304 # 400 to each microdimple treatment as an example. It represents.

The antibacterial activity value (R) is obtained by the following calculation formula (specified by JIS).
R = (Ut-U0)-(At-U0) = Ut-At
R: antibacterial activity value U0: logarithmic value of viable cell count (live cell count) immediately after inoculation of unprocessed test piece Ut: average of logarithmic value of viable cell count 24 hours after unprocessed test piece ( However, this time it is calculated after 8 hours, not after 24 hours)
At: average value of logarithmic value of viable cell count of the surface-treated test piece after 24 hours (however, this time, not after 24 hours but after 8 hours)
The unprocessed test piece corresponds to the sample (1) in FIG. 1, and the surface-treated processed test piece corresponds to the samples (2) to (5).

  JIS stipulates that an antibacterial activity value (R) is 2.0 or more (99% or more kill rate) to have an antibacterial effect, and in the above experimental results, sample (3) "SUS304 # 400 P43" Then, it can be defined that two of sample (4) "SUS304 # 400 PT1" have an antibacterial effect.

  However, for sample (2) "SUS304 # 400 MW" and sample (5) "SUS304 # 400 WS", the antibacterial activity value (R) is less than 2, but it is set on the vertical axis of FIG. 6 (B). When the antibacterial activity value (R) is 0, it is the state of the so-called untreated test piece (sample (1)). Compared with the case of "when 0 = untreated", the sample (2) " It is considered that a certain degree of antibacterial effect is expected for SUS304 # 400 MW ”and Sample (5)“ SUS304 # 400 WS ”.

  That is, according to the present embodiment, as shown in FIG. 3, FIG. 4, FIG. 5, etc., the micro-dimple treatment is performed on the surface of the member to form dimples (dents, substantially concave spherical surfaces) in the form of minute recesses. By forming innumerable randomly, it is possible to produce an antibacterial, sterilizing or bactericidal effect (action) on the surface.

  Surface shape data obtained by observing the concave-convex pitch (interval between convex portions) of the minute concave portions of the sample (2) “SUS304 # 400 MW” is shown in FIG. 7 (A). As shown in FIG. 9, the concave-convex pitch (interval between convex portions) range (μm) of the sample (2) is about 20 to 35 μm, and the average concave-convex pitch (interval between convex portions) is about 25.7 μm. The depth range of the recess is about 0.6 to 0.9 μm, and the average depth of the recess is about 0.77 μm.

Further, FIG. 7B shows surface shape data obtained by observing the uneven pitch of the minute recesses of the sample (3) "SUS304 # 400 P43". As shown in FIG. 9, the concavo-convex pitch (interval between convex portions) range (μm) of the sample (3) was about 1.7 to 7.3 μm, and the average concavo-convex pitch (interval between convex portions) was 3.56 μm. It becomes a degree. The depth range of the recess is about 0.2 to 1.0 μm, and the average depth of the recess is about 0.51 μm.
Note that, as shown in FIG. 10, the actually measured distance between the convex portions of the minute irregularities is in the range of approximately 1.7 to 7.3 μm, and the depth of the concave portions is in the range of approximately 0.2 to 1.0 μm. there were.

In addition, FIG. 8A shows surface shape data obtained by observing the uneven pitch of the minute recesses of the sample (4) "SUS304 # 400 PT1". As shown in FIG. 9, the concave-convex pitch (interval between convex portions) range (μm) of the sample (4) was about 0.4 to 1.0 μm, and the average concave-convex pitch (interval between convex portions) was 0.72 μm. It becomes a degree. The depth range of the recess is about 0.04 to 0.17 μm, and the average depth of the recess is about 0.10 μm.
In addition, as shown in FIG. 10, the measured intervals of the convex and concave portions of the minute unevenness are in the range of about 0.4 to 1.0 μm, and the depth is in the range of about 0.04 to 0.17 μm. It was

  Further, FIG. 8B shows surface shape data obtained by observing the uneven pitch of the minute recesses of the sample (5) "SUS304 # 400 WS". As shown in FIG. 9, the concave-convex pitch (interval between convex portions) range (μm) of the sample (5) is about 81 to 183 μm, and the average concave-convex pitch (interval between convex portions) is about 124.4 μm. Further, the depth range of the recess is about 1.5 to 4.6 μm, and the average depth of the recess is about 3.10 μm.

  By the way, the sample (1) and the samples (3), (4), etc. are not so different in uneven pitch (distance between convex portions or concave portions) and depth, but the samples (3), (4) It has a very remarkable antibacterial or sterilization effect.

  Although this is a point where detailed analysis is awaited, the dimple-shaped minute recesses formed by the micro-dimple treatment are formed by grinding or lapping the surface of the stainless steel member (sample) like the sample (1). Unlike the formed recesses (recesses (streaks, grooves) whose bottoms extend continuously in a streak pattern), each recessed part in which the surface of the member is cut into a dimple shape by ejected media (shot material particles) It is considered that one of the reasons is that adjacent concave portions are independently formed in innumerable random numbers by being partitioned (divided or defined) by peripheral convex portions.

  That is, according to the data provided by the Tokyo Metropolitan Institute of Health and Safety, the size of E. coli (O157, O111, etc.) is 1.1 to 1.5 μm (horizontal dimension) × 2.0 to 6 It is about 0.0 μm (length), and Escherichia coli is unable to move and move freely because it gets stuck in the minute concave portion formed by the microdimple treatment or climbs on the convex portion and die. It is possible to predict that an antibacterial effect (effect) will occur due to the rotational movement of the flagella, which grows relatively long in a state in which such movement / motion is restricted, and self-damage to death. ..

  The size of Salmonella is 0.7-1.5 μm (horizontal dimension) × 2.0-5. As with Escherichia coli, a member having innumerable minute irregularities formed on the surface thereof by the microdimple treatment according to the present embodiment is also used for bacteria having a size of 0 μm (length) and similar sizes. Is considered to have antibacterial or sterilizing and bactericidal effects.

  That is, the antibacterial member in which the number of dimple-shaped minute recesses is formed on the surface by the microdimple treatment according to the present embodiment is applied to “general bacteria such as Escherichia coli and Salmonella, which are gram-negative bacteria with flagella” Considered possible.

  As described above, according to the present embodiment, the bottom of the concave portion is not formed on the surface of the stainless steel member by the microdimple process, instead of the concave portion (straight line, groove) extending in a linear shape. By forming an infinite number of minute recesses, which are defined by the bottom and the protrusions and are formed independently of each other, an antibacterial or sterilizing or bactericidal effect (or bacterial growth) against bacteria such as E. coli. (Suppressive effect).

  That is, according to the present embodiment, by forming a plurality (innumerable) of dimple-shaped minute concave portions on the surface of the member by the microdimple treatment, the surface of the member is given an antibacterial (or sterilization, sterilization) effect. It is possible to provide an antibacterial surface treatment method and an antibacterial member having an antibacterial (or sterilization, sterilization) effect (or a bacteriostatic growth suppressing effect).

   In particular, as shown in FIGS. 6 (A) and 6 (B), as shown in samples (3) and (4), the average concavo-convex pitch (distance between convex portions) (μm) of the dimple-shaped minute concavities and convexities is set. , 3.56 (≈4.0) μm or less, or in the range of 0.72 (≈0.7) to 3.56 (≈4.0) μm, or 0.72 (≈0.7) μm By forming it at a level of less than or equal to a higher level, a higher antibacterial or sterilization / bactericidal effect (or bacteriostatic effect) can be produced on the surface of the member.

  Further, as shown in FIG. 10, as in Samples (3) and (4), the measured unevenness pitch (distance between convexes) (μm) of the dimple-shaped minute unevenness was 7.3 (≈8.0). ) Or less, or in the range of 0.4 to 7.3 (≈8.0) μm, or 0.4 μm or less, a higher antibacterial or sterilization / sterilization effect ( Alternatively, the effect of inhibiting bacterial growth can be produced. At this time, the depth of the recess can be about 1.0 μm or less, or about 0.04 to 1.0 μm, or about 0.04 μm or less.

Further, as shown in FIG. 11, the degree of formation of minute recesses formed by the size of the media (shot material) used for the micro-dimple treatment (such as pitch of recesses, entrance diameter and depth of recesses) is Since it is determined to some extent, the presence or absence of antibacterial or sterilization or bactericidal effect (or bacteriostatic effect) can be arranged to some extent by the size such as the particle size of the medium (shot material) used for the microdimple treatment.
That is, according to the present embodiment, in consideration of the results shown in FIGS. 11, 5, 10 and the like, as in the samples (3, (4)), the shot material has a particle size of about 3 μm or less, or It is considered that an antibacterial effect, a sterilization effect, or a bactericidal effect (or an effect of suppressing bacterial growth) can be produced within a range of about 3 μm or about 1 μm or less.

  Here, in the fine concavo-convex forming process (micro dimple process) according to the present embodiment, a member such as a contact member to be processed by ejecting the media (shot material, abrasive particles) as described above by a known ejection device. This can be done by colliding with the surface of.

  For example, a blast device can be used as the injection device, and as an example of the blast device, for example, "PNEUMA BLASTER" (model: SC series, SG series, etc.) manufactured by Fuji Manufacturing Co., Ltd. can be used. it can. Further, for example, those described in JP-A-2019-25584 can be used.

  More specifically, as an injection device for injecting injection particles toward the surface of a member, a known blasting device (blasting device) for injecting an abrasive (fine particles) together with a compressed gas (air, argon, nitrogen, etc.) Processing device) can be used.

The blasting device (blasting device) is a suction-type blasting device that injects abrasives by using the negative pressure generated by the injection of compressed gas, and the abrasives that drop from the abrasives tank are compressed gas. Gravity-type blasting device that injects and injects compressed gas into the tank in which the abrasive is put, and the abrasive flow from the abrasive tank is added to the compressed gas flow from the separately supplied compressed gas supply source. There are commercially available direct pressure blasting devices that combine and inject, and blower blasting devices that inject the above direct pressure compressed gas flow onto the gas flow generated by the blower unit. Any of these can be used for jetting the above-mentioned jet granules.
Further, a water jet that jets shots at high pressure together with a liquid such as water can also be used.

  By the way, in the present embodiment, the dimple-shaped minute recesses are formed innumerably randomly by the micro-dimple treatment, but the present invention is not limited to this, and the surface of the member such as the contact member to be treated is chemically By performing polishing (chemical etching), a plurality (a large number) of minute concave portions can be formed at random. For chemical polishing (chemical etching), for example, it is assumed that an acidic chemical such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid or the like and iron (III) chloride are prepared in an aqueous solution at an arbitrary ratio and used.

  Further, by subjecting the surface of a member such as the contact member to be treated to an argon bombardment treatment, it is possible to form a plurality (a large number) of irregularities of submicron or less on the contact surface at random.

  The antibacterial member according to the present invention can be applied to, for example, a processing target contact member with which a processing target contacts, and in that case, for example, storage, storage, transportation, sliding, sieving, stirring equipment, cooking balls, for cooking It can be applied to members used for various processes including instruments, surgical instruments, medical instruments and the like.

  Further, the antibacterial member according to the present invention is not limited to the contact member to be treated as described above, and is a vehicle handle (grip portion of a strap), other handles or handles, a door knob. It is applicable to any member such as a handle, a toilet seat, or any other member that is touched by humans or animals, or any member that randomly forms a large number of dimple-shaped minute recesses for the purpose of antibacterial (or bacterial growth suppression).

  Further, the antibacterial effect (bacterial growth suppression effect) by the microdimple treatment according to the present embodiment is, for example, in the case of a stainless material, the surface finish specifications such as # 400, # 700, 2B of the base material before the treatment. Regardless of which, it is considered that the same effect can be obtained with any of them, so that the present invention can be applied to any stainless steel material.

  The antibacterial member according to the present invention can be a resin member, and the material thereof is not particularly limited. For example, ceramics can be used, and in the case of a metal member, it can be made of metal (alloy) such as iron, aluminum, or titanium.

  The present invention is not limited to the above-described embodiments of the invention, and various modifications can be made without departing from the scope of the invention.

  INDUSTRIAL APPLICABILITY The present invention can provide an antibacterial (or sterilization, sterilization) effect on the surface of a member by forming a large number of dimple-shaped minute recesses on the surface of the member, which is useful in the industrial field where hygiene is a problem. Yes available.

Claims (2)

There are countless dimple-shaped minute recesses on the surface of the member that come into contact with bacteria, the maximum value of the uneven pitch is 7.3 μm or less and the minimum value is 0.4 μm or more, and the maximum depth of the recesses is An antibacterial feature characterized by imparting an antibacterial action to the surface of a member by forming a minute recess having a value of 1.0 μm or less and a minimum value of 0.04 μm or more by a projection process of projecting a shot material. Surface treatment method. A de Inpuru like minute recess formed in innumerable by a projection process of projecting shots, the minimum value is less than or equal to the maximum value of the unevenness pitch 7.3μm is at 0.4μm or more, the depth of the recess in Rukoto comprising a surface in contact with the bacteria member having fine recesses is and minimum 0.04μm or more in the 1.0μm or less the maximum value of the, that gave an antimicrobial effect on the surface of the member Characteristic antibacterial member.