JP4021595B2 - fishing rod - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fishing rod capable of maintaining excellent water repellency over a long period of time.
[0002]
[Prior art]
Conventionally, for example, in Japanese Patent Application Laid-Open No. 5-268858, a resin layer in which fluorine resin particles are mixed in a resin having a high adhesion made of a urethane resin or an acrylic resin and firmly adhered to a soot tube is provided on the inner surface of the soot tube. A formed through rod is disclosed.
[0003]
Japanese Patent Laid-Open No. 5-268858 discloses an intermediate fishing rod in which an epoxy resin containing fluorine resin fine particles and silicon resin fine particles is applied on a cored bar, and then a prepreg is wound, and pressure heating and firing are performed. Yes.
[0004]
[Problems to be solved by the invention]
However, all of the above-described conventional techniques use a resin having high adhesion such as urethane resin, acrylic resin, epoxy resin, etc. as the binder resin of the coating material to be applied. Even if mixed, such a resin could not provide high water repellency. That is, the contact angle of these resins with water was as small as less than 120 ° and the water repellency was low.
[0005]
Further, as in the former prior art (JP-A-5-268858), it is difficult to form irregularities on the surface of the resin layer simply by mixing particles in the resin, and the latter prior art (JP-A-5-268858). In the case of No. Gazette), the surface of the coating layer was smoothed by the metal core due to the production method, and the surface of the epoxy resin did not become uneven. Therefore, the water repellency could not be increased from the surface shape.
[0006]
The present invention has been made in order to solve such problems. The object of the present invention is to improve the water repellency of the portion of the surface of the rod tube that contacts the fishing line, and to prevent the fishing line from adhering to the rod tube and the occurrence of fishing line resistance. It is an object of the present invention to provide a fishing rod capable of reducing the above.
[0007]
Another object of the present invention is to provide a fishing rod that improves durability and enables long-term use.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, fine water-repellent particles are mixed in the water-repellent resin on the inner peripheral surface of a soot tube formed by winding a prepreg impregnated with a synthetic resin in a reinforcing fiber. The ratio of the water-repellent particles on the surface of the water-repellent film is larger than the ratio of the water-repellent particles on the side of the tub tube, and the water-repellent particles are mixed in the water-repellent film. The ratio is more than 30% (area ratio of the cross section) and not more than 70%, and the surface of the water-repellent coating has minute irregularities formed by a collection of the minute water-repellent particles and the particle diameter of the minute water-repellent particles. Provided is a fishing rod characterized by having finer irregularities deeper than that.
[0009]
As described above, the fishing rod of the present invention is characterized in that a water-repellent film having a fine uneven surface formed by mixing water-repellent particles in a water-repellent resin is formed on the surface. Examples of the water-repellent resin include a fluorine-based resin and a silicon-based resin. Although other materials can be used as the water repellent resin, it is preferable to use a material having a surface property with a water contact angle of 130 ° or more, preferably 140 ° or more.
[0010]
The water-repellent particles include tetrafluoroethylene resin, tetrafluoroethylene resin-hexafluoropolypropylene copolymer resin, trifluorinated ethylene chloride resin, vinyl fluoride resin, vinylidene tetrafluoride resin, tetrafluoroethylene. -Perfluoroalkyl vinyl ether copolymer resin, fluorinated ethylene resin-ethylene copolymer resin, ethylene-trifluoroethylene copolymer resin, and other silicon oxide and silicon resins.
[0011]
Further, the surface of the water repellent coating has a fine irregular surface deeper than the particle size of the water repellent particles.
As described above, the surface of the water-repellent coating containing a water-repellent resin and water-repellent particles and having a fine uneven surface has a contact angle of water droplets of 130 ° or more, preferably 140 ° or more, particularly preferably 150 to 180 °. It has a very high super water repellency.
[0012]
A fine uneven surface deeper than the particle size of the water-repellent particles can be formed by increasing the amount of the solvent on the surface when the water-repellent coating is formed and volatilizing the solvent. Alternatively, as will be described later, it is also possible to form by mixing wear-resistant particles having a particle diameter larger than that of the water-repellent particles.
[0013]
The thickness of the water-repellent coating can be arbitrarily set within a range of 1 μm to 100 μm, and is particularly preferably 3 μm to 20 μm. When providing a projection for the fishing line guide, it is formed to a thickness that exposes the top of the projection, and the fishing line is received at the top of the abrasion-resistant projection to prevent wear of the water-repellent coating. I can do it.
[0014]
It is preferable that the water-repellent particles mixed in the water-repellent resin have not only a single shape and size but also two or more different shapes and sizes. By using water-repellent particles having various shapes and sizes, the uneven shape on the surface of the water-repellent coating can be made complicated, thereby further improving the water repellency.
[0015]
It is preferable to make the ratio of the water-repellent particles on the surface of the water-repellent coating larger than the ratio of the water-repellent particles on the side of the tubule. This is because the physical properties of the material, such as the difference in specific gravity between the water-repellent resin and the water-repellent particles, the centrifugal force is used when forming the coating, or the water-repellent resin with different water-repellent particle content is used. This can be achieved by coating multiple times.
Thus, by increasing the ratio of the water-repellent particles on the surface of the water-repellent coating to the side of the tub tube, the water repellency of the surface of the water-repellent coating can be further increased, and the resin as the binder is the tub tube. By increasing the number on the side, it is possible to relatively improve the adhesion to the soot tube.
[0016]
The water-repellent coating can be formed of a plurality of layers, but it is preferable to form a single layer or a plurality of layers that are integrally heat-cured simultaneously. This is because even a water repellent coating can prevent delamination.
[0017]
The mixing ratio of the water-repellent particles in the water-repellent coating is preferably more than 30% (cross-sectional area ratio), and more preferably in the range of 40 to 70%. Thereby, the protrusion of water-repellent particles can be increased, and a highly water-repellent surface can be obtained.
[0018]
In order to make the surface of the water-repellent coating a fine irregular surface deeper than the particle size of the water-repellent particles, the wear-resistant particles can be mixed into the water-repellent coating. In this case, by forming the wear-resistant particles so as to protrude from the surface of the water-repellent coating, even if the fishing line comes into contact with the surface of the water-repellent coating, early wear of the water-repellent coating can be prevented.
[0019]
The size of the wear-resistant particles is not particularly limited, but is preferably larger than the size of other particles contained in the water-repellent film, for example, the water-repellent particles. As a result, a plurality of types of particles having different sizes protrude to form a complex uneven surface composed of fine unevenness and fine unevenness. Note that the amount of the wear-resistant particles is preferably smaller than the amount of the water-repellent particles.
[0020]
Thus, by forming a complex uneven surface on the surface of the water repellent coating, the durability of the coating can be improved and the water repellency can be further improved. In particular, when the water-repellent particles and the wear-resistant particles have different properties such as materials, it is possible to form an uneven surface to which characteristics according to the properties are added.
[0021]
The mixing ratio of the wear-resistant particles is not particularly limited, but 1 wt% or more, usually 3 to 30 wt% is appropriate.
[0022]
A spiral projection made of an abrasion-resistant material can be provided on the surface of the soot tube. This spiral projection functions as a fishing line guide.
[0023]
In the fishing rod of the present invention, the water-repellent coating is formed by spray coating, dipping (after removing the coating liquid, removing unnecessary parts), brush coating, etc. It can also be carried out by winding the prepreg, winding an FR prepreg thereon, and heat-molding it by a conventional method. It is also possible to form using a plating method.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a fishing rod according to an embodiment of the present invention will be described with reference to the accompanying drawings. Examples of the fishing rod of the present invention include, for example, a parallel rod, an anti-parallel rod, an inlay rod, a swing rod, a through rod, a fishing rod having an outer guide, and a fishing rod without an outer guide (such as ayu rod). Maru)).
[0025]
FIG. 1 shows a through-type swing rod as an example of the fishing rod of the present invention. The fishing rod is composed of a main rod tube 2, a middle rod tube 6 joined to the former rod tube 2 via a joint portion 4, and a tip rod joined to the middle rod tube 6 via a joint portion 8. It consists of a tube 10. In FIG. 1, a fishing rod having a plurality of middle rods 6 is shown. However, the present invention is not limited to this, and a fishing rod having one middle rod 6 may be used. Moreover, although the fishing rod which has several rods was shown in FIG. 1, it is not limited to this, The fishing rod comprised only with one rod can be sufficient.
[0026]
In the fishing rod shown in FIG. 1, the main rod tube 2 is provided with a gripping portion 14 to which a reel 12 is detachably attached, and the fishing line 16 fed from the reel 12 is provided on the main rod tube 2. After being introduced into the main rod pipe 2 via the fishing line introduction guide 18, it is fed out from the tip of the tip rod pipe 10 via the intermediate rod pipe 6.
[0027]
Further, a top guide 20 is detachably attached to the tip of the tip rod tube 10, and the fishing line 16 is smoothly and stably sent out from the tip of the tip rod tube 10 by the top guide 20. .
[0028]
In such a fishing rod, the frictional resistance of the fishing line 16 is reduced on the inner peripheral surfaces of the main rod tube 2, the middle rod tube 6, and the tip rod tube 10, respectively, and excellent water repellency is maintained over a long period of time. A water-repellent coating is applied to keep it going.
[0029]
In the following description, the frictional resistance of the fishing line 16 is reduced on the inner peripheral surfaces of the main rod tube 2, the middle rod tube 6 and the tip rod tube 10 to maintain excellent water repellency over a long period of time. The case where a water repellent film is applied will be described. In addition, since the water repellent coating applied to the inner peripheral surface of the main rod tube 2, the middle rod tube 6, and the tip rod tube 10 is the same, in the following description, as an example, The case where a water repellent film for reducing the frictional resistance of the fishing line 16 and maintaining excellent water repellency over a long period of time is applied to the peripheral surface will be described.
[0030]
FIG. 2 shows a partially cut-away cross-sectional view of a midline fishing rod main body formed by winding a prepreg sheet in which a reinforcing fiber is impregnated with a synthetic resin. As shown in FIG. 2, a spiral projection 24 as a fishing line guide is formed on the inner peripheral surface of the rod body 22.
[0031]
FIG. 3 is a cross-sectional view showing the structure of the inner peripheral surface of the soot tube main body 22 according to one embodiment of the present invention. As shown in FIG. 3, the soot tube main body 22 has a three-layer structure of an inner layer 22a, an intermediate layer 22b, and an outer layer 22c. The inner layer 22a and the outer layer 22 are composed of a carbon circumferential fiber layer, a glass scrim cloth layer (woven fabric layer), a carbon axial fiber layer, or a combination thereof, and the intermediate layer 22b is an axial fiber layer or a tilted fiber layer. It is composed of layers mainly composed of
[0032]
As shown in FIG. 3, a plurality of protrusions 24 having a predetermined height are formed on the inner peripheral surface of the soot tube main body 22 at a predetermined pitch, and a water-repellent resin containing minute water-repellent particles. A water repellent coating 28 made of is fixed. In addition, it is preferable that the super water-repellent coating 28 has a complex uneven surface having not only “fine unevenness” but also “minute unevenness” having a depth smaller than that.
[0033]
In the present embodiment, “fixing” means forming the water-repellent coating 28 by, for example, painting (liquid, powder, etc.), printing, winding of a prepreg or a resin film, vapor deposition, plating, or other adhesion. Means. Further, “water repellency” means that the contact angle of water droplets is at least 130 degrees, preferably 140 degrees or more, and more preferably 150 degrees to 180 degrees.
[0034]
The plurality of protrusions 24 are preferably made of an abrasion resistant material. Usable wear-resistant materials include, for example, fiber reinforced resins using ceramic fibers, carbon fibers, glass fibers, etc., those using organic fibers such as PET, aramid, PTFE, PE, etc., or synthetic fibers A resin film, a thread, a ceramic material (ring shape), or the like can be used. Further, the height of the protrusions 24 is preferably set in the range of 0.1 to 1 mm, and preferably 0.2 to 0.6 mm. Moreover, it is preferable to set the pitch of the some projection part 24 in the range of 2-20 mm, preferably 3-10 mm. However, when forming on the outside of the soot tube, it may be as described above, but 1 to 10 protrusions per soot tube may be used.
[0035]
The water-repellent coating 28 is fixed over a region between the plurality of protrusions 24, and the thickness thereof is set to be smaller than the height of the protrusions. In this case, the thickness of the water-repellent coating 28 is set in the range of 1 to 100 μm, preferably 3 to 20 μm.
[0036]
As shown in FIG. 3, the water-repellent coating 28 is thinnest at the top 28 a of the protrusion 24, thickest at the base 28 b of the protrusion 24, and has an average thickness in a region 28 c between the protrusions 24. Show.
[0037]
The water-repellent coating 28 is formed by using a water-repellent resin such as a fluorine resin or a silicone resin in which water-repellent particles 26 such as fluororesin particles are dispersed and mixed. When the prepreg sheet is wound to form the tubule body 22, the water-repellent resin mixture is fixed to the prepreg sheet in advance, so that the tubule body 22 is completed and the tubule body 22 is completed. It is formed on the inner peripheral surface of the main body 22.
[0038]
The minute uneven surface of the water-repellent coating 28 is formed by combining a convex portion formed by a collection of a plurality of water-repellent particles bonded by a binder and a concave portion formed between the convex portions. In this case, the concept of “micro” refers to the microscopicity that allows the air that has entered the concave portion of the minute unevenness to be held in the concave portion and that the water droplet does not enter the concave portion. As a specific example, when the water-repellent coating 28 is viewed on a plane, the number of combinations of concave portions and convex portions is 100 or more or 1000 in terms of unit area (for example, 1 mm ² ). As mentioned above, Preferably, it means that 5000-1 million pieces or more are formed. In other words, the concept of “small” means that the height difference between the concave portion and the convex portion is 10 μm or less, preferably 0.1 to 5 μm, and between the concave portion and the convex portion. It means that the pitch W is set to 10 μm or less, preferably 0.1 to 5 μm.
[0039]
Further, the fine uneven surface of the water-repellent coating 28 is an uneven surface deeper than the particle size of the fine water-repellent particles, and the concept of “fine” in this case is that air that has entered the concave portion of the fine concave portion is in the concave portion. It is held so fine that water droplets do not enter the recesses. As a specific example, when the super water-repellent coating is viewed on a plane, the number of combinations of recesses and projections is the unit area. It means that 10 or more or 100 or more, preferably 1000 to 500,000 or more are formed per (for example, 1 mm ² ). In other words, the concept of “fine” means that the height difference between the concave and convex portions is 10 μm or less, preferably 0.2 to 5 μm, and between the concave and convex portions. It means that the pitch is set to 100 μm or less, preferably 0.2 to 5 μm.
[0040]
If the water-repellent particles 26 are densely arranged on the side of the tubule body 22, the adhesion (adhesion) area between the tubule body 22 and the water-repellent coating 28 is reduced. Since the fixing property (adhesiveness) of the water-repellent coating 28 may be lowered, the water-repellent particles 26 are preferably concentrated on the surface side of the water-repellent coating 28 and in the vicinity thereof.
[0041]
Thus, by concentrating the water-repellent particles 26 on the surface side of the water-repellent coating 28 and in the vicinity thereof, the boundary surface between the tub tube main body 22 and the water-repellent coating 28 has little or no water-repellent particles 26. Therefore, the area of adhesion (adhesion) between the tub tube main body 22 and the water repellent coating 28 can be increased. As a result, it is possible to improve the fastness (adhesion) of the water repellent coating 28 to the soot tube main body 22.
[0042]
As described above, according to the present embodiment, the plurality of protrusions 24 are formed at a predetermined pitch, and the water-repellent coating 28 having a minute uneven surface is formed in a region between the plurality of protrusions 24. By providing, it is possible to provide a fishing rod that can reduce the frictional resistance of the fishing line 16 and can maintain excellent water repellency for a long period of time. That is, for example, even when seawater, water, etc. are covered with the fishing rod {in this embodiment, the inner peripheral surface of the middle rod tube 6 (the rod tube body 22)}, water droplets and the like are quickly removed by the minute uneven surface S. Therefore, it is possible to prevent water droplets or the like from adhering to the water repellent coating 28. That is, when water droplets or the like adhere to the water repellent coating 28, the fishing line 16 is attracted to the water repellent coating 28 by the water droplets or the like, and the contact state between the fishing line 16 and the water repellent coating 28 increases. However, the presence of minute uneven surfaces can prevent water droplets or the like from adhering to the water-repellent coating 28, so that the contact of the fishing line 16 with the water-repellent coating 28 can be reduced and the yarn resistance can be reduced. It is possible to protect the water-repellent coating 28 by reducing the contact of the fishing line.
[0043]
FIG. 4 is a cross-sectional view showing a water-repellent coating 28 formed on the inner peripheral surface of the soot tube main body 22 according to another embodiment of the present invention, enlarged 1,000 to 20,000 times. . In this example, the water-repellent coating 28 contains the wear-resistant particles 30 in addition to the water-repellent particles 26. As the wear resistant particles 30, silica, alumina, glass, SiC, stainless steel, or the like can be used.
[0044]
As the wear-resistant particles 30, particles having a particle diameter larger than the particle diameter of the water-repellent particles 26 contained in the water-repellent film 28 and smaller than the film thickness of the water-repellent film 28 can be used. The particle size of the water repellent particles 26 is, for example, 0.1 μm to 1 μm, and the particle size of the wear resistant particles 30 is, for example, 0.2 μm to 5 μm.
[0045]
Therefore, the water-repellent coating 28 contains the small-diameter water-repellent particles 26 and the large-diameter wear-resistant particles 30 in the water-repellent resin as a binder, and as a result, a surface where the large and small particles are combined. I will provide a. In other words, a comparatively smooth micro uneven surface is formed by the small-diameter water-repellent particles 26, and a surface in which the large-diameter wear-resistant particles 30 protrude from the surface is obtained.
[0046]
In the water-repellent coating 28 having the structure shown in FIG. 4, the ratio of the water-repellent resin to the total amount of the coating is preferably, for example, less than 60 or 50% by weight. By using the amount of the water-repellent resin in such a range, the surface of the water-repellent coating 28 can be easily and deeply formed.
[0047]
FIG. 5 shows various shapes of the wear-resistant particles 30 used in the water-repellent coating 28 shown in FIG. 5A shows a spherical shape, FIG. 5B shows an elliptical shape, FIG. 5C shows a columnar shape, and FIG. 5D shows a shape having a recess or a hole on the surface.
[0048]
The wear-resistant particles 30 preferably have a smooth shape with no corners or irregularities on the surface, and surface polishing is preferably performed to obtain such a surface. In addition, in order to improve the separability from other particles, for example, water-repellent particles, to improve adhesion to the binder, or to impart water repellency to the surface, the wear-resistant particles 30 may be coated. Is possible. Moreover, you may form a recessed part and a hole in the surface for the same reason.
[0049]
FIG. 6 is a cross-sectional view showing an inner surface portion of a soot tube body according to still another embodiment of the present invention. In this embodiment, the high adhesion layer 32 is formed between the inner surface of the soot tube main body and the water repellent coating 28, and the ratio of the water repellent particles 26 in the water repellent coating 28 is larger than that on the soot tube main body 22 side. It is relatively increased on the surface side of the water repellent coating 28.
[0050]
The high adhesion layer 32 is provided to roughen the inner surface of the soot tube body 22 and improve the adhesion of the water repellent coating 28. Examples of the material constituting the high adhesion layer 32 include an acrylic resin, an epoxy resin, a polyurethane resin, and a silicone resin. Note that this highly adhesive layer is not necessarily provided. Instead of providing the high adhesion layer 32, the inner surface of the soot tube main body 22 may be roughened, or the water repellent coating 28 may be directly coated.
[0051]
In the water-repellent coating 28 according to this embodiment, as described above, the ratio of the water-repellent particles 26 is relatively larger on the surface side of the water-repellent coating 28 than on the side of the tub tube main body 22. That is, the amount of the binder is relatively increased on the side of the soot tube main body 22. Therefore, it is possible to further improve the adhesion between the inner surface of the soot tube main body 22 or the high adhesion layer 32 and the water-repellent coating 28. Further, by increasing the ratio of the water-repellent particles 26 on the surface side, the water repellency of the surface of the water-repellent coating 28 can be further increased.
[0052]
Such a water-repellent coating 28 in which the ratio of the water-repellent particles 26 is increased on the surface side can be formed by utilizing, for example, the specific gravity difference between the water-repellent particles and the binder. That is, it is possible to adjust the ratio of the water-repellent particles 26 to be increased on the surface side using a centrifugal force in a curing stage such as heat curing or photocuring of the film, or in the previous stage.
[0053]
It is also possible to make the water-repellent particles 26 float on the surface due to the difference in surface tension. Alternatively, a paint having a small proportion of the water-repellent particles 26 may be applied, a paint having a large proportion of the water-repellent particles may be applied on the semi-cured resin layer, and the inner and outer layers may be cured by heating.
[0054]
As described above, in the present invention, in order to further improve the water repellency of the water-repellent coating 28, the water-repellent particles 26 are mixed into the water-repellent coating 28, thereby forming the protrusions 24 and the wear-resistant particles 30. On the uneven surface of the water-repellent coating 28, fine uneven portions are formed by the water-repellent particles 26.
[0055]
That is, the water-repellent particles 26 become convex portions, and the gaps between the water-repellent particles 26 become concave portions.
[0056]
The method of forming the water-repellent film 28 using such water-repellent particles 26 is, for example, by preliminarily fixing a water-repellent material mixture (synthetic resin) in which the water-repellent particles 26 are dispersed and mixed to a prepreg sheet. After the prepreg sheet is wound to form the tub tube main body 22, the water repellent material mixture is subjected to heat treatment to expose the water repellent particles 26, and as a result, the gap between the water repellent particles 26 and the water repellent particles 26. A minute uneven surface corresponding to the combination shape is formed.
[0057]
As another method for forming a film, for example, after the tub tube main body 22 is completed, a water-repellent material mixture in which the water-repellent particles 26 are dispersed and mixed is laminated (sprayed and painted) on the inner peripheral surface of the tub tube main body 22. The water repellent material mixture may be subjected to heat treatment.
[0058]
Although the above embodiment demonstrated the example which formed all the water-repellent coatings on the inner surface of a soot tube, this invention is applicable similarly also when forming a water-repellent coating on the outer surface of a soot tube. The formation of the water-repellent coating may be performed on the whole or a part of the tub tube, or may be applied to all the nodes using only one tub tube.
[0059]
【The invention's effect】
As described above in detail, according to the present invention, since a water-repellent film in which water-repellent particles are mixed with a water-repellent resin is used and the surface thereof is formed on an uneven surface, A surface is obtained, and adhesion of water droplets can be effectively prevented. As a result, it is possible to prevent the fishing line from adhering to the surface of the rod tube due to water droplets and increasing the fishing line resistance.
[Brief description of the drawings]
FIG. 1 is a diagram showing the overall configuration of an example of a fishing rod according to the present invention.
FIG. 2 is a partially cut-away cross-sectional view showing a midline fishing rod main body according to the present invention.
FIG. 3 is a cross-sectional view showing the structure of the inner peripheral surface of a soot tube main body according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of the repellent formed on the inner peripheral surface of the soot tube main body according to another embodiment of the present invention. Sectional drawing which expands and shows an aqueous film.
FIG. 5 is a view showing the shapes of various water-repellent particles.
FIG. 6 is an enlarged cross-sectional view showing a water-repellent coating formed on the inner peripheral surface of a soot tube body according to still another embodiment of the present invention.
[Explanation of symbols]
6 ... Middle pipe 22 ... Steel pipe body 24 ... Projection 26 ... Water-repellent particles 28 ... Water-repellent coating 30 ... Abrasion-resistant particles 32 ... High adhesion layer

Claims (3)

A water-repellent coating formed by mixing minute water-repellent particles in a water-repellent resin is formed on the inner peripheral surface of a soot tube formed by winding a prepreg impregnated with a synthetic resin into a reinforcing fiber, and the surface of the water- repellent coating The ratio of the water-repellent particles in is higher than the ratio of the water-repellent particles on the side of the tubule, the mixing ratio of the water-repellent particles in the water-repellent coating is more than 30% (area ratio of the cross section), 70 %, And the surface of the water-repellent coating has minute irregularities made of a collection of the minute water-repellent particles and minute irregularities deeper than the particle diameter of the minute water-repellent particles. . 2. The fishing rod according to claim 1 , wherein the water-repellent coating is mixed with a smaller amount of wear-resistant particles having a larger particle size than the water-repellent particles. 3. The fishing rod according to claim 1, wherein the fine irregularities on the surface of the water repellent coating are complex irregularities in which a plurality of types of particles having different sizes protrude from the surface.

Images