JP2013087921A - Manufacturing method for antibacterial gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for an antibacterial gasket, that dispenses with a post-treatment such as a brushing process, preventing formation of unevenness on a rubber surface in the antibacterial gasket containing antibacterial agents in the material, that secures a sealing property and has a high antibacterial agent density on the rubber surface, thus exhibiting excellent antibacterial effects.SOLUTION: A tubular molded product is formed using a molding material prepared by adding antibacterial particles to a rubber material and kneading it. The molded product is provided with a skin layer hard to contain antibacterial particles on the surface and with fastening margin for each gasket on the inner and outer circumferential surfaces. Then, the molded product is cut in the direction crossing with the center axis to manufacture a gasket. At this time, the antibacterial particles are exposed by the cutting on the axis end surface of the gasket, while the antibacterial particles are not exposed by the remaining of the skin layer on the inner and outer circumferential surfaces of the gasket as a sealing surface with the fastening margin.

Description

  The present invention relates to a gasket according to a sealing technique, and more particularly to a method for manufacturing an antibacterial gasket. The antibacterial gasket of the present invention is used, for example, in the fields of housing equipment, home appliances, food processing equipment, or medical equipment.

  In recent years, awareness of hygiene and cleanliness have increased, and nosocomial infections caused by MRSA and food poisoning caused by pathogenic E. coli have become major social problems. With such a background, antibacterial properties are being imparted to various products, and there is an increasing demand for imparting antibacterial properties to seal products.

  For example, gaskets are often used as seal products for food and beverage production machines, cooking utensils, household watering products, health appliances, medical instruments, etc., and most of the gasket materials are rubber (including elastomers, the same applies hereinafter) In order to prevent bacterial growth and slimming, a gasket having antibacterial properties is preferable.

  Antibacterial properties are obtained by including an antibacterial agent in the product material. There are various types of antibacterial agents depending on their characteristics, effects, and applications, but they are roughly classified into inorganic and organic types depending on the material. Further, as the inorganic antibacterial agent, silver-based inorganic particles in which silver is supported on ceramic particles are generally used.

  The antibacterial gasket is usually formed by adding antibacterial agent particles to a rubber material and then kneading and dispersing. As the molding method, compression molding or injection molding is usually employed. Generally, in the molding of rubber, a skin layer is formed on the surface of a molded product by heat and pressure during molding. In the skin layer, the proportion of rubber becomes very large, and inorganic particles such as fillers are buried inside the molded product. For this reason, when adding functionality to rubber by adding functional fillers such as high thermal conductivity and high electrical conductivity, there is a problem that the surface thermal conductivity and electrical conduction are hindered due to this skin layer. Yes (Patent Document 1).

  Similarly, the antibacterial rubber to which particles of an inorganic antibacterial agent are added also has a problem that the concentration of the antibacterial agent on the rubber surface becomes very low due to this skin layer, and the antibacterial effect is not exhibited. On the other hand, if a large amount of the inorganic antibacterial agent is added, the concentration of the antibacterial agent on the rubber surface is increased to some extent, but the function as a gasket such as strength and sealability may be impaired. For this reason, the antibacterial effect is enhanced by increasing the concentration of the antibacterial agent by increasing the concentration of the antibacterial agent by carrying out a brushing process on the rubber surface after the addition is limited to an appropriate amount. Examples of the brushing process include buffing, shot blasting, and paper finishing (Patent Documents 2 and 3).

  However, when these brushing treatments are performed, irregularities are formed on the rubber surface, so that the sealing performance of the gasket may be deteriorated, and such post-treatment after molding causes an increase in manufacturing cost.

  On the other hand, in the case of organic antibacterial agents, the antibacterial agent concentration on the rubber surface is relatively high because the antibacterial agent moves from the inside to the surface by bleed out. However, there is a possibility that the organic antibacterial agent may elute into water or a sealing object. For this reason, since an elution component may touch or be taken in to a human body, use of an organic type antibacterial agent is not preferable.

  From the above, in the antibacterial rubber gasket using an inorganic antibacterial agent, there is no post-treatment such as a brushing treatment, so that no irregularities are formed on the rubber surface, and the sealing property can be secured. On the other hand, a gasket having a high antibacterial agent concentration on the rubber surface and capable of exhibiting an excellent antibacterial effect is desired.

JP 2002-57254 A JP-A-8-104863 JP 2000-1229029 A

  In view of the above points, the present invention eliminates the need for post-treatment such as a brushing treatment in an antibacterial gasket containing an antibacterial agent in the material, so that no irregularities are formed on the rubber surface, thereby ensuring a sealing property. Furthermore, an object of the present invention is to provide a method for producing an antibacterial gasket, which is capable of exhibiting a high antibacterial agent concentration on the rubber surface and thus exhibiting an excellent antibacterial effect.

  In order to achieve the above object, an antibacterial gasket manufacturing method according to claim 1 of the present invention forms a tubular molded article using a molding material obtained by adding and kneading antibacterial agent particles to a rubber material. The tubular molded article has a skin layer on the surface of which the antibacterial agent particles are unlikely to be contained, and has an inner peripheral surface and an outer peripheral surface with fastening portions for each gasket. A gasket is manufactured by cutting in a direction perpendicular to the central axis, and at this time, the antibacterial agent particles are exposed to the axial end surface of the gasket by the cutting, while the sealing surface is provided with the tightening margin. The antibacterial agent particles are not exposed on the inner and outer peripheral surfaces of the gasket due to the remaining skin layer.

  Moreover, the manufacturing method of the antibacterial gasket according to claim 2 of the present invention is characterized in that, in the manufacturing method according to claim 1, the tightening margin for each gasket is formed as a mountain shape having an arcuate cross section. To do.

  In the manufacturing method of the present invention having the above configuration, first, a tubular molded product is molded using a molding material obtained by adding and kneading antibacterial agent particles to a rubber material. The tubular molded product has a skin layer on its surface that hardly contains antibacterial particles. Moreover, the tubular molded product is provided with a tightening margin for each gasket on its inner and outer peripheral surfaces. As the tightening margin, for example, this is formed as a mountain shape with an arc cross section.

  Next, a gasket is manufactured by cutting the tubular molded product in a direction perpendicular to the central axis. When the molded product is cut, a large amount of antibacterial agent particles contained in the molded product are exposed on the cut surface, so that a surface portion having a high concentration of the antibacterial agent is formed. In the present invention, the cut surface is an axial end surface of the gasket, and the axial end surface of the gasket is a surface portion where the concentration of the antibacterial agent is high. Further, the axial end surface of the gasket is not a sealing surface but a surface that contacts water or a sealing object. Therefore, since the surface in contact with the water or the sealing object is a surface portion where the concentration of the antibacterial agent is high, an excellent antibacterial effect is exhibited.

  On the other hand, the inner peripheral surface and the outer peripheral surface of the gasket are not cut and remain as they are molded, and the skin layer remains. Therefore, the antibacterial agent particles are hardly exposed and the antibacterial effect is low. However, the inner and outer peripheral surfaces of this gasket are the surfaces to be sealed with fastening margins, and are in close contact with the mating material such as the flange when the gasket is mounted. Is small. Therefore, there is no problem even if the concentration of the antibacterial agent is low and the antibacterial effect is small.

  Therefore, according to the present invention, an excellent antibacterial effect is exhibited.

  In the production method of the present invention, the molded product is cut, but no post-treatment such as brushing is performed. Therefore, unevenness is formed on the rubber surface by post-treatment such as brushing, and the sealing performance of the gasket is not impaired. Further, even if the smoothness of the rubber surface is impaired in the cutting step, the cut surface is the end surface in the axial direction of the gasket, and the end surface in the axial direction is not the seal surface, so that the sealing performance is not affected.

  On the other hand, as described above, the inner peripheral surface and the outer peripheral surface of the gasket which is the sealing surface are left as they are without being cut, the skin layer remains, and the smooth state is maintained. Further, the inner peripheral surface and the outer peripheral surface of the gasket are provided with a fastening margin portion, and the fastening margin portion is in close contact with a mating member such as a flange.

  Therefore, according to the present invention, an excellent sealing effect is exhibited.

  The present invention has the following effects.

  As described above, according to the present invention, both an excellent antibacterial effect and an excellent sealing effect are exhibited. Therefore, in accordance with the intended purpose of the present invention, in the antibacterial gasket containing the antibacterial agent in the material, it is not necessary to perform a post-treatment such as a brushing process, so that no irregularities are formed on the rubber surface and a sealing property is ensured. In addition, an antibacterial gasket can be provided that has a high antibacterial agent concentration on the rubber surface and can exhibit an excellent antibacterial effect.

(A) is sectional drawing of the gasket manufactured by the manufacturing method based on the Example of this invention, (B) is a top view of the gasket Sectional view of a tubular molded product molded during the manufacturing process Sectional view showing the mounting state of the gasket

  The present invention includes the following embodiments.

(1) Inorganic antibacterial agent particles are added and kneaded to rubber, and then compression molding or injection molding is performed to obtain a molded product. The molded product has a cylindrical shape. Furthermore, the outer cylinder surface and the inner cylinder surface are composed of a plurality of arc-shaped peaks. The outer diameter / inner diameter and length of the cylinder, and the number and shape of the peaks vary depending on the use conditions and the sealing object. However, the shape of the adjacent mountain, the outer cylinder surface, and the inner cylinder surface is the same. Furthermore, the tops of the peaks and the bottoms of the valleys of the outer cylinder surface and the inner cylinder surface coincide with each other in a plane perpendicular to the length direction of the cylinder. Thereby, the ring obtained by the subsequent cutting process has a symmetrical shape with respect to the axis and the surface.

(2) A cutting process is performed on the valley of the molded product. Examples of the cutting method include a water jet, a press, and a rotary cutter. The rubber rings obtained by cutting are used as antibacterial rubber gaskets, except for both end faces of the cylinder. Since there is no scrap other than both end faces of the cylinder, there are very few parts to be discarded. Since the cut surface is a portion that was inside the rubber at the time of molding, the concentration of the antibacterial agent is high and the antibacterial effect is also high. Further, since the cut surface does not become a seal surface, even when the inorganic antibacterial agent particles are exposed or the surface smoothness is deteriorated by punching, the airtightness is not affected. On the other hand, the mountain-shaped surface, which is the surface during molding, is largely crushed due to strain caused by the compressive load at the time of sealing, and becomes a contact surface to the flange, etc., so the area in contact with water and the object to be sealed is very large Small. Therefore, even when the concentration of the antibacterial agent is low and the antibacterial effect is low, there is no problem.

(3) The manufactured gasket is as follows.
(3-1) An antibacterial gasket molded using a molding material obtained by adding and kneading antibacterial agent particles to a rubber material, and the sealing surface that is in close contact with the mating material at the time of use is not cut during the manufacturing process. The antibacterial agent particles are not exposed by providing a skin layer, and the antibacterial agent particles are exposed by cutting the surface other than the sealing surface that comes into contact with the sealing fluid at the time of manufacture. Antibacterial gasket.
(3-2) The antibacterial gasket according to the item (3-1), wherein an interference portion is provided on the seal surface, and the skin layer is provided on a surface of the interference portion. Gasket.
(3-3) The antibacterial gasket according to the item (3-2), wherein the fastening portion is formed as a mountain shape having an arc cross section.

  Next, embodiments of the present invention will be described with reference to the drawings.

  The manufacturing method according to the embodiment is to manufacture an antibacterial gasket (also referred to as an antibacterial gasket) 11 shown in FIGS. 1 (A) and 1 (B). This gasket 11 is an inorganic antibacterial agent for a rubber material. Is formed into a ring shape using a molding material added and kneaded with particles, and the cross-sectional shape thereof is rectangular (molded based on a rectangular shape), and antibacterial agent particles are respectively formed on the inner peripheral surface and outer peripheral surface thereof. Has a hard to contain skin layer. Further, the gasket 11 is formed as seal surfaces 12 and 13 for bringing the inner peripheral surface and the outer peripheral surface including the skin layer into close contact with the mating members 21 and 22 (see FIG. 3) such as flanges. The fastening margins 14 and 15 each having a mountain shape with a circular arc cross section are integrally provided. Therefore, the skin layer is provided on the surface of the fastening margins 14 and 15. On the other hand, the end surfaces in the axial direction of the gasket 11 are cut surfaces 16 and 17 cut in a direction perpendicular to the central axis 0, respectively, and no skin layer is provided on the cut surfaces 16 and 17, so that the antibacterial agent Many particles are exposed. The gasket 11 is a radial type gasket because the inner and outer peripheral surfaces thereof are the sealing surfaces 12 and 13. In FIGS. 1 and 3, a portion of the cross section of the gasket 11 containing a large amount of inorganic antibacterial particles is indicated with a number of dots on the figure, whereas the antibacterial agent A portion where the particles are hardly contained (including the skin layer) is shown without dots.

  When manufacturing the gasket 11 having the above structure, first, a tubular molded product shown in FIG. 2 is formed by compression molding or injection molding using a molding material obtained by adding and kneading inorganic antibacterial agent particles to a rubber material at a predetermined ratio. 1 is molded. Next, the tubular molded product 1 is cut for each gasket 11 in a direction perpendicular to the central axis 0, thereby producing the gasket 11 shown in FIG. The cutting method is a water jet method, a press method, a rotary cutter method, or the like. In any case, the cutting is performed at a valley portion between the peaks according to the cross-sectional shape of the fastening margins 14 and 15. No post-processing such as brushing is performed.

  The tubular molded product 1 shown in FIG. 2 is obtained by taking a large number of gaskets 11 (13 in the figure). Further, the molded article 1 contains antibacterial particles inside, but the surface thereof is hard to contain antibacterial particles over the entire surface (inner peripheral surface, outer peripheral surface and both axial end surfaces). Has a skin layer. Moreover, the molded product 1 is provided with the fastening margin parts 14 and 15 which show the mountain shape of the cross-section circular arc shape for every gasket 11 on the inner peripheral surface and outer peripheral surface, respectively. Further, the molded product 1 has annular burrs 2 formed at both ends in the axial direction.

  When the tubular molded article 1 shown in FIG. 2 is cut in a direction perpendicular to the central axis 0, a large amount of antibacterial agent particles contained in the molded article 1 are exposed on the cut surfaces 16 and 17 and thus exposed to the surface. A gasket surface portion having a high concentration of the antibacterial agent is formed, and the cut surfaces 16 and 17 are end surfaces in the axial direction of the gasket 11. Therefore, the axial end surface of the gasket 11 is a surface portion having a high concentration of the antibacterial agent. Further, as shown in the mounting state diagram of FIG. 3, the axial end surface of the gasket 11 is not a sealing surface in close contact with the mating members 21 and 22 but a surface that contacts water or a sealing object. Therefore, since the surface in contact with the water or the sealing object is a surface portion where the concentration of the antibacterial agent is high, an excellent antibacterial effect is exhibited. On the other hand, the inner peripheral surface and the outer peripheral surface of the gasket 11 are not cut and are left as they are molded, so that the skin layer remains. Therefore, the antibacterial agent particles are hardly exposed and the antibacterial effect is low. However, the inner peripheral surface and the outer peripheral surface of the gasket 11 are the surfaces that are provided with the tightening margins 14 and 15 to be the seal surfaces 12 and 13, and are in close contact with the mating members 21 and 22 when the gasket 11 is mounted. The area in contact with water and the sealing object is very small. For this reason, there is no problem even if the concentration of the antibacterial agent is low and the antibacterial effect is small. Therefore, an excellent antibacterial effect is exhibited by the above.

  In the manufacturing method according to the embodiment, as described above, the cutting process of the molded product 1 is performed, but no post-processing such as a brushing process is performed. Therefore, unevenness is formed on the rubber surface by post-treatment such as brushing, and the sealing performance of the gasket 11 is not impaired. Even if the smoothness of the rubber surface may be impaired in the cutting process, the cutting surfaces 16 and 17 are the axial end surfaces of the gasket 11 and the axial end surfaces are not sealing surfaces. Will not affect. On the other hand, the inner peripheral surface and the outer peripheral surface of the gasket 11 that are used as the seal surfaces 12 and 13 are not cut and remain as they are molded, and the skin layer remains, thus maintaining a smooth state. Further, the inner peripheral surface and the outer peripheral surface of the gasket 11 are provided with fastening margins 14 and 15, and the fastening margins 14 and 15 are in close contact with the mating members 21 and 22 with a predetermined surface pressure. Therefore, an excellent sealing effect is exhibited by the above.

  Therefore, according to the said manufacturing method, the antimicrobial gasket 11 which exhibits both the outstanding antimicrobial effect and the outstanding sealing effect can be manufactured.

DESCRIPTION OF SYMBOLS 1 Molded product 2 Burr part 11 Gasket 12, 13 Sealing surface 14, 15 Fastening margin 16, 17 Cut surface 21, 22 Opposing material 0 Center axis

Claims (2)

A tubular molded product is molded using a molding material obtained by adding and kneading antibacterial agent particles to a rubber material. At this time, the tubular molded product has a skin layer on the surface of which the antibacterial agent particles are hardly contained. In addition, the inner peripheral surface and the outer peripheral surface are provided with a tightening margin for each gasket,
Next, a gasket is manufactured by cutting the tubular molded product in a direction perpendicular to the central axis thereof, and at this time, the antibacterial agent particles are exposed by the cutting on the axial end surface of the gasket, A method for producing an antibacterial gasket, characterized in that the antibacterial agent particles are not exposed by the skin layer remaining on an inner peripheral surface and an outer peripheral surface of the gasket which are provided with a fastening portion and serve as a sealing surface. In the manufacturing method of Claim 1,
The manufacturing method of the antibacterial gasket characterized by shape | molding the fastening allowance part for every said gasket as a mountain shape of cross-sectional arc shape.

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