JP6380240B2 - Interdental cleaning tool - Google Patents

Description

  The present invention relates to an interdental cleaning tool.

  Interdental cleaning tools are widely used to prevent tooth decay and periodontal disease, for example, by removing food traps between teeth and plaque that causes tartar that tends to adhere to the roots of teeth. It has been. The interdental cleaning tool includes, for example, a base material portion made of a synthetic resin and a soft portion made of an elastomer, and the base material portion is provided at a handle base material portion to be a handle and a tip portion of the handle base material portion. It has a long and thin shaft-shaped core substrate portion that is continuously provided, and the soft portion has a cleaning soft portion that covers the distal end side of the core substrate portion, and the distal end side of the core substrate portion and the cleaning soft portion The resin interdental cleaning tool which uses as a cleaning part has been put into practical use (see, for example, Patent Documents 1 to 3). Such an interdental cleaning tool is configured to remove plaque and food waste by inserting the cleaning part between the teeth, and to reduce inflammation of the gums by massaging the root of the tooth at the cleaning part Has been.

  As a manufacturing method of the resin interdental cleaning tool, a synthetic resin is supplied to the first molding space of the first mold to mold the base material part, and the obtained base material part is used as the second molding of the second mold. A manufacturing method is widely used in which a soft part is molded by loading the space and supplying an elastomer to the second molding space. Usually, synthetic resin is supplied to the plurality of first molding spaces using a first mold having a plurality of first molding spaces and a second mold having the same number of second molding spaces as the first molding spaces. Forming a primary molded product in which a plurality of base material portions are connected by a runner portion, loading the primary molded product into a second molding space, and supplying an elastomer to the plurality of second molding spaces. The interdental cleaning tool is molded simultaneously.

  When the elastomer is supplied to the second molding space, the mold structure is simplified and the elastomer is relatively highly viscous, and the region corresponding to the tip side of the cleaning soft portion in the second molding space is filled with the elastomer. Considering that defects are likely to occur, a gate is usually arranged in a region corresponding to the tip side of the core base material portion of the base material portion loaded in the second molding space, and the core is formed in the second molding space. Elastomer is supplied from the distal end side of the base material portion toward the proximal end side.

  When the elastomer is supplied as described above, the opening area of the gate cannot be increased, the injection pressure cannot be increased, and the elastomer injection pressure around the core substrate near the gate varies. Therefore, the core base material portion is curved to the side where the injection pressure is low, and a molding defect occurs in that the tip side of the core base material portion is not sufficiently covered with the elastomer. Moreover, the elastomer is heated to near the melting temperature of the core base material part in order to improve its fluidity and adhesion to the core base material part, and the core base material part softens and deforms due to the heat of the elastomer. Since it becomes easy, a core base material part deform | transforms even if there is slight variation in injection pressure.

  In view of such a problem, a pair of positioning members that are disposed opposite to each other in a direction substantially perpendicular to the primary molded product in a region where the cleaning soft portion in the second molding space is molded, and are supported so as to be close to and away from each other. A method of manufacturing an interdental cleaning tool using a second mold provided with a plurality of holding pins for use has been proposed (see Patent Document 4). According to this second mold, by bending the pair of holding pins on at least the front and back surfaces of the core base material portion, the core base material portion is curved by contact with the high injection pressure or the elastomer. And the deformation can be prevented and the cleaning soft part can be formed almost accurately on the tip side of the core base part. Moreover, patent document 4 discloses the resin composition containing a synthetic resin, glass fiber, and talc as a material of a base material part.

Japanese Patent No. 4236571 Japanese Patent No. 3002668 Special table 2001-506514 gazette International Publication No. 2013/176297

  When the cleaning unit is inserted between the teeth, a large compression force acts in the axial direction. Also, during interdental cleaning of molars, in particular molars and the back side of the front teeth, etc., it is necessary to insert the cleaning part between the teeth and put it in and out with the curved part from the tip part to the intermediate part. A large bending load acts on the part. For this reason, even if the synthetic resin constituting the base material portion has relatively high mechanical properties, the core base material portion and thus the cleaning portion will break during the interdental cleaning, and non-recoverable deformation is likely to occur. In addition to shortening the service life of the interdental cleaning tool, there is a risk of damaging the oral cavity due to sudden breakage during use.

  In addition, when a base material part is shape | molded using super engineering plastics, such as polyether sulfone, as a synthetic resin, a core base material part will be easy to bend and the breakage of a cleaning part can be prevented. However, high injection temperature is essential for super engineering plastic molding, and cooling time after injection molding becomes long. Therefore, productivity of interdental cleaning tools decreases, and material costs are high. There is a problem that the cost becomes considerably high.

  Further, according to the research of the present inventor, in the manufacturing method of Patent Document 4, the core base material portion and the holding pins for positioning the core base material portion are provided in the second mold when the cleaning soft portion is molded. A recess is likely to be formed at the contact position, the cross-sectional area of the core base material portion is reduced at the position of the recess, the stress generated in the core base material portion is increased, and there is a recess at a site where high stress is concentrated. In this case, local elongation and compression are likely to occur in the recess of the core base material, and the core base near the axial position where the recess is formed due to bending stress acting during interdental insertion or interdental cleaning of the cleaning unit. The point which a material part bends was discovered.

  The reason why the concave portion is formed on the surface of the core base material part in the manufacturing method of Patent Document 4 is that the manufacturing method shortens the molding time and imparts good fluidity and adhesion to the base material part to the elastomer. Therefore, although the second mold is heated to a relatively high temperature, the shortening of the molding time may cause a difference in molding shrinkage of the core base material portion made of synthetic resin. The tip of the holding pin changes because the way of contact with the part changes, and the contact with the high temperature elastomer causes thermal expansion of the core base part and vibration of the core base part when the elastomer is supplied. Bite into the core base material portion, and it is estimated that a concave portion is formed in the core base material portion.

  An object of the present invention is to provide an interdental cleaning tool that can effectively prevent the core base material part and hence the cleaning part from being broken during interdental insertion of the cleaning part and during interdental cleaning by the cleaning part. It is.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that, in the interdental cleaning tool having a recess on the surface of the core base material portion, for example, as a material for the base material portion, a synthetic resin and a fibrous filler And a filler selected from plate-like fillers, a relatively high rigidity resin composition is used, and mechanical properties such as the elastic modulus of the resin composition and the core base material of the holding pin in the second molding space By appropriately combining the depth adjustment method of the core base material concave portion such as the contact pressure with respect to the core, by setting the maximum depth of the concave portion formed on the surface of the core base material portion within a predetermined range, Decrease in mechanical properties of the core base material due to a decrease in the cross-sectional area, and local elongation and compression inside the core base material due to the presence of recesses in the stress-concentrated part, and a large bending load acts Even when the core substrate part and the cleaning part are broken (broken) It found that can significantly prevent the raw, and have completed the present invention.

  That is, this invention provides the interdental cleaning tool of following (1)-(6).

  (1) A base material portion made of a synthetic resin and a soft portion made of an elastomer covering at least a part of the base material portion, the base material portion having a handle base material portion serving as a handle, and a handle base material portion An elongated shaft-shaped core base material portion connected to the tip of the core base material portion, and the soft portion has at least a cleaning soft portion covering the core base material portion, and the core base material portion and the cleaning soft portion And an interdental cleaning tool comprising a cleaning part for interdental cleaning, wherein the base material part is a resin composition in which at least one selected from a fibrous filler and a plate-like filler is added to a synthetic resin. The cleaning part has a first side part and a second side part, penetrates the cleaning soft part in each of the first side part and the second side part, and the maximum depth of the surface of the core base material part Two or more cleaning part recesses connected to the core base part recesses having a thickness of 0.01 mm to 0.085 mm are spaced apart in the axial direction of the cleaning part. Interdental cleaner, wherein the door.

  In addition, the maximum depth of a core base-material part recessed part means the largest distance among the shortest distances from the outer surface to the bottom face of the opening part of a core base-material part recessed part. That is, as shown in FIG. 22, the center line in the depth direction of the core base material recess 14a (core base) passes through the center P1 of the opening of the cleaning recess 14 and the center P2 of the bottom of the cleaning recess 14. A surface that includes DL of the material portion recess space and is parallel to the center line CL of the core base material portion 12 is defined as a reference surface BS, and the core base material portion is defined by a cut surface CS parallel to the reference surface BS. When it is assumed that the concave portions 14a are sequentially cut, the core base portion concave portion 14a is obtained from a line segment UL connecting the front end T and the rear end B at the cut surface CS of the opening of the core base portion concave portion 14a. This means the maximum length of all the cut surfaces among the lengths of the center line DLa that extends in parallel to the line segment DL in the depth direction. Moreover, the 1st side part and 2nd side part of a cleaning part are one side half part of the outer peripheral surface of the cleaning part shape | molded by one metal mold | die in the 2nd metal mold | die which forms a cleaning part, and the other side. It means the remaining half on one side of the outer peripheral surface of the cleaning part formed by a mold.

According to the interdental cleaning tool of the above (1), the core substrate is used in spite of constituting the substrate portion using a resin composition containing a synthetic resin and a filler having a specific shape, as in the prior art. The part has a core base part recess having a maximum depth of 0.01 mm to 0.085 mm, so that the core base part has high mechanical properties while being difficult to bend and easily break, and a part where stress tends to concentrate The local elongation or compression inside the core base material portion generated by the presence of the concave portion is alleviated, and by using the resin composition, the core base material portion in the concave portion and the periphery thereof is used. Reduction in mechanical properties such as rigidity due to reduction in cross-sectional area is suppressed.
Therefore, if the interdental cleaning tool of (1) is used, during interdental insertion of the cleaning unit, or during interdental cleaning in which the cleaning unit inserted between the teeth is reciprocated and moved up and down, especially the back side of the molar teeth and lower anterior teeth Even if it is between teeth, the breakage (break) of a core base material part and a cleaning part can be prevented effectively, and the service life of an interdental cleaning tool can be extended.

  Here, the maximum cross-sectional area of the core base material portion at the position corresponding to the core base material portion recess is the 55.0 to 99.99 of the cross-sectional area of the core base material portion at the position adjacent to the core base material recess. It is preferable to set to 6%, and it is a more preferable embodiment to set to 80.0-97.9%. If comprised in this way, the stress concentration in a core base-material part recessed part will be decreased, and the breakage of the core base-material part at the time of insertion between teeth and the cleaning between teeth can be prevented much more effectively.

(2) The above-mentioned (1), wherein the plurality of core base part recesses on the first side and the plurality of core base part recesses on the second side are arranged facing each other across the core base part. Interdental cleaning tool.
According to the interdental cleaning tool of the above (2), by disposing the core base part concave part of the first side part and the core base part concave part of the second side part through the core base part, It has the effect of alleviating local elongation and compression in and around the core base material due to stress concentration while minimizing the deterioration of the mechanical properties of the core base material portion around the core base material recess. This further increases the level of the cleaning part.

(3) The shaft portion covered with the cleaning soft portion of the core base material portion is composed of a distal end side core body and a proximal end side core body connected thereto, and the diameter of the distal end side core body is 0.4 mm to 0.6 mm. The interdental cleaning tool according to (1) or (2) above, wherein the diameter of the proximal-side core body is 0.8 mm to 2 mm.
According to the interdental cleaning tool of (3) above, even if the shaft portion (tip side core body) covered with the cleaning soft part of the core base material part is relatively thin as in the above range, the interdental Since the breakage of the cleaning portion is effectively prevented at the time of insertion or interdental cleaning, the service life can be extended while improving the operability.

(4) The interdental cleaning tool according to any one of (1) to (3), wherein the fibrous filler is at least one selected from the group consisting of glass fiber, wollastonite, and potassium titanate fiber.
According to the interdental cleaning tool of the above (4), by using the specific fibrous filler as a filler to be added to the resin composition constituting the base material portion, the base material portion, particularly the core base material portion. Mechanical properties can be easily enhanced. Moreover, the said fibrous filler is comparatively preferable also from the surface of the safety | security with respect to a human body. The fibrous filler has an aspect ratio (fiber length / fiber diameter) of usually 2 or more, preferably 5 or more, more preferably 10 or more, and a dimension of micron order or millimeter order, preferably micron order. It is an inorganic compound.

(5) The interdental cleaning tool according to any one of (1) to (4), wherein the plate-like filler is at least one selected from the group consisting of glass flakes, mica, talc, and clay.
According to the interdental cleaning tool of the above (5), by using the specific plate-like filler as the filler to be added to the resin composition constituting the base portion, the base portion, particularly the core base portion. Can improve the mechanical properties. Moreover, the said plate-shaped filler is preferable also from the surface of the safety | security with respect to a human body, or a price. The plate-like filler is a more effective filler than the fibrous filler from the viewpoint of improving the flexibility of the core base material portion. The plate-like filler is an inorganic compound having a plate-like shape, a scale-like shape, or a flake-like shape and having a dimension on the order of microns.

(6) The interdental cleaning tool according to any one of (1) to (5) above, wherein the blending amount of the filler is 10 to 50% by weight of the total amount of the resin composition.
According to the interdental cleaning tool of (6) above, the base material portion in the molding step using the first mold is obtained by using a resin composition in which the filler is blended in an amount of 10 to 50% by weight of the total amount of the resin composition. While maintaining a high level of moldability, it is very easy to adjust the maximum depth of the core substrate recess in the molding process using the second mold to the above specified range. It is possible to improve the performance.

(7) The interdental cleaning tool according to any one of (1) to (6), wherein the synthetic resin is a thermoplastic resin having a melting point of 150 ° C. or higher.
According to the interdental cleaning tool of (7) above, the productivity of the interdental cleaning tool can be improved by shortening the molding time of the base material portion, particularly the cooling time after molding, thereby improving the production efficiency, and consequently the teeth. The manufacturing cost of the interim cleaning tool can be reduced. In addition, from the viewpoint of further enhancing the effect, among thermoplastic resins having a melting point of 150 ° C. or higher, a thermoplastic resin in which at least a part is crystalline is more preferable.

  According to the interdental cleaning tool of the present invention, during interdental insertion and interdental cleaning, especially when inserting interdental or interdental cleaning on the back side of the molar or mandibular anterior teeth or interdental cleaning, the core substrate part and thus the cleaning part bend ( Breakage) can be effectively prevented.

It is a front view which shows typically the structure of an interdental cleaning tool coupling body. It is a schematic diagram which shows the structure of the principal part of the interdental cleaning tool coupling body shown in FIG. 1, (a) is a front view, (b) is a side view. It is a front view which expands and shows typically the connection part vicinity of an interdental cleaning tool coupling body. It is sectional drawing in the IV-IV cut surface line | wire shown in FIG. It is a schematic diagram which expands and shows the cleaning part of 1st Embodiment, (a) is a front view, (b) is a side view. It is sectional drawing in the VI-VI cut surface line shown to Fig.5 (a). It is a front view which expands and shows typically the composition of the cleaning part of a 2nd embodiment. It is sectional drawing of the cleaning part shown in FIG. It is sectional drawing which shows typically the structure of the cleaning part of 3rd Embodiment. It is sectional drawing which shows typically the structure of the cleaning part of 4th Embodiment. It is a schematic diagram which expands and shows the structure of the cleaning part of 5th Embodiment, (a) is a front view, (b) is a side view. It is sectional drawing in the XII-XII cut surface line shown to Fig.11 (a). It is a front view which expands and shows the structure of the cleaning part of 6th Embodiment. It is sectional drawing in the XIV-XIV cut surface line shown in FIG. It is a schematic diagram for demonstrating the shaping | molding method of the base material part by a 1st metal mold | die. It is a schematic diagram for demonstrating the shaping | molding method of the soft part by a 2nd metal mold | die. It is an expansion schematic diagram for demonstrating the shaping | molding method of the soft part by a 2nd metal mold | die, (a) shows the state immediately before shaping | molding of the soft part by a 2nd metal mold | die, (b) is the softness by a 2nd metal mold | die. The state immediately after molding of the part is shown. It is a schematic diagram for demonstrating the structure of the principal part of the 2nd metal mold | die of other embodiment. It is a schematic diagram for demonstrating the structure of the principal part of the 2nd metal mold | die of another embodiment. It is a schematic diagram for demonstrating the structure of the principal part of the 2nd metal mold | die of another embodiment. (A)-(c) is a schematic diagram for demonstrating the edge part shape of the holding pin of another embodiment. It is a schematic diagram for demonstrating the depth of a core base-material part recessed part.

<Interdental cleaning tool>
The interdental cleaning tool of the present invention includes a handle base material portion serving as a handle and a long and thin shaft-shaped core base material portion continuously provided on the distal end side of the handle base material portion, and a base material made of a specific resin composition And a soft part including a cleaning soft part made of an elastomer and covering the tip side of the core base part, and a cleaning soft part covering the tip side of the core base part And a cleaning part. In addition, in the interdental cleaning tool of the present invention, the cleaning portion has a plurality of cleaning portion recesses on the first and second side portions, respectively, and the cleaning portion recess penetrates the cleaning soft portion and the core base material portion. It is characterized by being connected to a core base part recess having a maximum surface depth of 0.01 mm to 0.085 mm (0.01 mm or more and 0.085 mm or less).

  As described above, the interdental cleaning tool of the present invention combines the material characteristics and the structural characteristics so that the interdental insertion of the cleaning part, especially the molars and the lower front of the lower jaw, is performed. This prevents the core base material part and therefore the cleaning part from being broken at the time of cleaning or interdental cleaning. First, the material which comprises a base material part and a soft part as a material characteristic is demonstrated in detail.

  The resin composition constituting the base material portion includes a synthetic resin and at least one filler selected from the group consisting of a fibrous filler and a plate-like filler. By including the specific filler, the mechanical properties (rigidity, etc.) and heat resistance of the resin composition are improved, and even if the base material portion, particularly the core base material portion is exposed to a high temperature in the second mold, the core base Since the degree of expansion, melting, or softening of the material portion is reduced, the maximum depth of the concave portion of the core base material generated by the contact of the holding pin with the core base material portion is prevented from becoming very large. Adjustment of the thickness becomes easy. The maximum depth of the core substrate recess can be adjusted, for example, by appropriately selecting the type of synthetic resin, the type of filler, the blending amount, and the like. Furthermore, the maximum depth of the core substrate recess can be finely adjusted by appropriately selecting the diameter, area, shape, contact pressure, etc. of the core substrate contact surface of the holding pin, for example.

  As the synthetic resin, a synthetic resin commonly used in the field of interdental cleaning tools can be used without particular limitation, for example, polypropylene, polybutylene terephthalate, polyethylene, polyethylene terephthalate, polyamide, polycyclohexylene dimethylene terephthalate, saturated polyester resin, Examples thereof include thermoplastic resins such as polymethyl methacrylate, cellulose propionate, thermoplastic polyurethane, polyamide, polycarbonate, and ABS (acrylonitrile / butadiene / styrene) resin. Among these thermoplastic resins, a thermoplastic resin having a melting point of 150 ° C. or higher such as polypropylene, polybutylene terephthalate, and polyamide is preferable from the viewpoint of preventing the cleaning portion from being bent. From the viewpoint, a thermoplastic resin such as polypropylene and polybutylene terephthalate having a melting point of 150 ° C. or higher and at least a part of which is crystalline is more preferable, and polypropylene is more preferable. Polypropylene is particularly preferable because it has a low molding temperature, can shorten the cycle time and improve productivity, and has a small thermal load on the molding equipment. When a thermoplastic resin having a melting point of 150 ° C. or higher is used as the thermoplastic resin in the resin composition, it is possible to shorten the molding time of the base material portion, particularly the cooling time, and increase the production efficiency. As a result, the interdental cleaning tool The productivity of the interdental cleaning tool can be reduced. A thermoplastic resin can be used individually by 1 type or in combination of 2 or more types as needed.

  Of the fillers, the fibrous filler is not particularly limited, but glass fiber, wollastonite, potassium titanate fiber, etc. can be preferably used from the viewpoint of safety and availability to the human body, and the price is taken into account. Then, glass fiber and wollastonite are more preferable, and glass fiber is more preferable. A fibrous filler can be used individually by 1 type or in combination of 2 or more types. The fibrous filler is preferable to the plate-like filler from the viewpoint of improving the mechanical properties of the base material portion, particularly the core base material portion (particularly the axial rigidity of the core base material portion).

Further, the plate-like filler is not particularly limited, but from the viewpoint of safety to human body and availability, glass flakes, mica, talc, clay, etc. can be preferably used, mica, talc, etc. are more preferable, talc is further preferable. A plate-shaped filler can be used individually by 1 type or in combination of 2 or more types. The plate-like filler is preferable to the fibrous filler from the viewpoint of improving the flexibility of the core base material portion.
Various commercial products can also be used as the fibrous filler and the plate-like filler.

  Moreover, in this invention, a fibrous filler and a plate-shaped filler can also be used together. In this combined use, by appropriately selecting the use ratio of the fibrous filler and the plate-like filler, the core base material portion is maintained while maintaining the flexibility of the core base material portion so that the core base material portion is not easily broken. Therefore, the deterioration of the mechanical properties of the core base material portion around the concave portion due to the formation of the concave portion of the core base material portion can be compensated. Specific examples of the combined use include, for example, combined use of glass fiber and talc. In the combined use of glass fiber and talc, for example, by using more talc than glass fiber, it is possible to simultaneously maintain the flexibility of the core base material and improve the mechanical properties.

  In the above resin composition, the use ratio of the synthetic resin and the filler is not particularly limited. However, in the manufacturing method of the interdental cleaning tool using the first and second molds, the base in the process using the first mold is used. From the viewpoint of easily adjusting the maximum depth of the concave portion of the core base material portion to the predetermined range in the process using the second mold while maintaining the molding processability of the material portion at a high level, The blending amount is preferably 10 to 50% by weight of the total amount of the resin composition, more preferably 20 to 45% by weight of the total amount of the resin composition, and further preferably 25 to 40% by weight of the total amount of the resin composition. If the blending amount of the filler is less than 10% by weight, the mechanical properties of the base material portion, particularly the core base material portion, may be insufficient, and it becomes difficult to adjust the maximum depth of the core base material recess, There is a tendency that folding around the concave portion of the base material portion is likely to occur. On the other hand, if the blending amount of the filler exceeds 50% by weight, it tends to be difficult to maintain the flexibility of the core base material part to the extent that the breakage can be prevented.

  Examples of the elastomer constituting the soft part include thermoplastic elastomers such as styrene, olefin, and polyamide, nylon elastomers such as 6 nylon, 6-6 nylon, 6-10 nylon, and 6-12 nylon, and silicon rubber. Thermosetting elastomers such as urethane rubber, fluoro rubber, natural rubber, and synthetic rubber can be used. In particular, a material having compatibility with the synthetic resin material constituting the base portion is preferable. For example, when the base portion is made of polypropylene, the soft portion is preferably made of a polyolefin-based elastomer or a styrene-based elastomer. .

Next, structural features of the interdental cleaning tool 1 will be described with reference to the drawings.
As shown in FIG. 1 to FIG. 6, the interdental cleaning tool 1 is provided with a cleaning part 2 for interdental cleaning and a handle part 3 as a handle when distinguished by its function. A base material portion 10 made of a synthetic resin and a soft portion 20 made of an elastomer are provided. As shown in FIGS. 1 to 3, the interdental cleaning tool 1 is manufactured in the form of an interdental cleaning tool coupling body 5 formed by connecting a plurality of interdental cleaning tools 1 in a detachable manner in parallel. A user cuts off the interdental cleaning tool 1 in order from the one side of the interdental cleaning tool connector 5 and sequentially uses it. In addition, in FIG. 1, although the 10 interdental cleaning tools 1 were connected in parallel and the interdental cleaning tool coupling body 5 was comprised, the connection number of the interdental cleaning tools 1 can be set arbitrarily.

(Base material part)
The base material portion 10 is configured to include a resin composition containing a specific filler, preferably a thermoplastic resin composition, and as shown in FIGS. Handle base material portion 11, an elongated shaft-shaped core base material portion 12 provided continuously with the tip end portion of handle base material portion 11, and a connecting portion 13 for detachably connecting adjacent handle base material portions 11. ing.

  The handle base material portion 11 is formed in a flat and slender plate shape, but any shape other than the flat and slender plate shape, for example, a cross-sectional shape is circular as long as it is a shape that can be easily picked with fingers and cleaned between teeth. It can also be formed into an oval shape (elliptical, oval, rounded rectangle, oval, oval, cocoon, etc.), a rod shaped like a teardrop or polygon. The distal end portion of the handle base material portion 11 is configured so as to narrow toward the core base material portion 12 side, and is smoothly connected to the core base material portion 12. The handle base material portion 11 can be set to any size as long as it is easy to clean between the teeth by picking with a finger. In the handle base material portion 11 shown in FIGS. 1 and 2, for example, the length L1 is 10 mm. The width W1 is set to 4 mm to 10 mm, and the thickness t1 of the grip portion is set to 1.0 mm to 2.0 mm. As described above, since the handle base material portion 11 is thin, when the base material portion 10 is molded, it is possible to reduce dimensional variations due to the shrinkage of the handle base material portion 11 and to prevent sinking. The poor loading of the base material part 10 to the second molds 40 and 41 for forming the part 20 can be prevented.

  The core base material portion 12 is formed in a substantially straight and elongated shaft shape, and the handle base material portion 11 and the core base material portion 12 are arranged in substantially the same axis, and the core base material portion 12 and the handle base material portion 11 are arranged. Are arranged in the same plane. An exposed portion 12a that is exposed to the outside is formed on the gripping portion side of the core base material portion 12, and a core body 12b that can be inserted between teeth is formed on the tip side portion of the core base material portion 12 by being covered with an elastomer. The core base material portion 12 is formed in a gently tapered shape that decreases in diameter as it goes to the tip side.

  The length L2 of the exposed portion 12a of the core base material portion 12 from the end point of the round (curved portion) on the side surface of the distal end portion of the handle base material portion 11 configured to be narrow to the base end portion of the covering portion 21a of the soft portion 20 Is set to, for example, 10 mm to 50 mm, preferably 10 mm to 25 mm in consideration of operability, and the length L3 of the cleaning soft portion 21 is set to, for example, 12 mm to 22 mm in consideration of cleanability between the teeth. ing.

  The angle θ1 formed by the taper shape of the outer surface of the core base material portion 12 with respect to the center line of the core base material portion 12 is set to 0.2 ° to 1.5 ° in consideration of the insertability between teeth. . The diameter of the tip side portion of the core body 12b is set to 0.4 mm to 0.6 mm, and the diameter of the base end portion of the core body 12b is set to 0.8 mm to 2.0 mm. In the present invention, since the diameters of the proximal end side and the distal end side of the core main body 12b are set thin as described above, the operability and handleability of the interdental cleaning tool 1 can be improved. The combination of the resin composition and the core base part recess having the maximum depth within a predetermined range can remarkably prevent the cleaning part 2 from being broken during interdental insertion and interdental cleaning. The cross-sectional shape of the core base material portion 12 is preferably a circular shape from the viewpoint of interdental insertion, relaxation of stress concentration, and the like, but may be an oval shape, a teardrop shape, a polygonal shape, or the like. Further, the diameter D of the curved end portion of the distal end portion of the covering portion 21a of the cleaning soft portion 21 is set to 0.5 to 1.2 mm, and the distal end side portion of the core body 12b is at least 5 mm or more from the distal end portion of the core body 12b. It is comprised so that it can insert reliably between teeth.

  However, the angle θ1 formed by the taper shape of the core base material portion 12 is set to the same angle θ1 over the entire length of the core base material portion 12, but continuously or stepwise as it goes to the tip side of the core base material portion 12. It can also be set to be smaller. Alternatively, the exposed portion 12a may be formed in a shaft shape having the same diameter over the entire length, and only the core body 12b may be formed in a gently tapered shape that decreases in diameter toward the distal end side. Further, it is possible to omit the exposed portion 12a and connect the core body 12b directly to the handle base material portion 11.

  In the present embodiment, the present invention is applied to the I-type interdental cleaning tool 1 in which the center line extending in the longitudinal direction of the handle base material portion 11 and the axis of the core base material portion 12 are arranged in substantially the same axis. However, the present invention can also be applied to an interdental cleaning tool in which the center line of the handle base material portion 11 and the axis of the core base material portion 12 are arranged in an arbitrary positional relationship. The present invention can also be applied to an interdental cleaning tool in which the center line and the axis of the core base material portion 12 are arranged in parallel at an interval, and the center line of the handle base material portion 11 is the axis of the core base material portion 12. On the other hand, for example, the present invention can be applied to a so-called L-shaped interdental cleaning tool 1 provided at an angle of 120 °.

  As shown in FIGS. 2 to 4, the connecting portion 13 is integrally formed with the handle base material portion 11 between the adjacent handle base material portions 11, and the base end side and the tip end side of the handle base material portion 11 are formed. One pair is provided at intervals in the longitudinal direction. The connecting portion 13 is elongated in the length direction of the handle base material portion 11 and is formed in a trapezoidal shape (isosceles trapezoidal shape in FIG. 3) in a front view. The number of the connecting portions 13 can be arbitrarily set, and it is possible to provide only one. However, when configured as such, the connection strength of the adjacent base material portions 10 is sufficient when the interdental cleaning tool 1 is manufactured. After the base material portion 10 is molded, the connecting portion 13 is broken when the mold is opened, the base material portion 10 is broken, the soft portion 20 cannot be formed, or the connecting portion 13 is bent. Thus, the base material part 10 cannot be loaded at an appropriate position in the second molding space 42 (see FIG. 16) for forming the soft part 20, and a molding defect may occur. It is preferable to provide two or more at intervals in the length direction.

  The cross section of the connecting portion 13 is formed in a trapezoidal shape or a triangular shape (in FIG. 4, an isosceles trapezoidal shape or an isosceles triangular shape), and as shown by a virtual line in FIG. Bending the cleaning tool 1 in the direction of overlapping each other, concentrating the bending force on the boundary portion 13a, and the arcuate side surface 11a of the side edge of the handle base material portion 11 contacting the outer surface of the connecting portion 13, By applying a large force in the direction of pulling away from the boundary portion 13a according to the principle of leverage, the interdental cleaning tool 1 can be cleanly separated without significant deformation of the connecting portion 13 in the boundary portion 13a. It is configured. However, the shape of the connecting portion 13 is arbitrary as long as it can be easily and cleanly separated by bending the adjacent interdental cleaning tool 1 in the direction of overlapping each other with the connecting portion 13 as the center. It can be formed in the shape of

  Moreover, when adding a fiber material to the synthetic resin material which comprises the base material part 10, a fiber material is orientated so that the length direction may turn into the direction along the length direction of the base material part 10. Preferably, the bending strength of the base member 10 and the buckling strength with respect to the axial direction can be improved, and the core base member 12 can be folded or seated when the interdental cleaning tool 1 is used. Bending can be effectively prevented.

(Soft part)
As shown in FIGS. 1 to 6, the soft portion 20 is made of an elastomer, is integrally formed with the base material portion 10, and includes a cleaning soft portion 21 that is externally mounted on the core base material portion 12. However, as the soft portion 20, it is also possible to provide an annular insertion restricting portion for restricting insertion between teeth at the proximal end portion of the core body 12b, or to provide a non-slip portion on the handle base portion 11. . The insertion restricting portion and the non-slip portion can be formed independently of the cleaning soft portion 21, but the mold structure becomes complicated, so that the insertion restricting portion and the anti-slip portion are formed so as to continue to the base of the cleaning soft portion 21. Is preferred.

  The cleaning soft portion 21 includes a covering portion 21a covered by the core base material portion 12 and a plurality of cleaning protrusion portions 21b formed on the covering portion 21a so as to protrude outward at intervals in the length direction. Have.

  If the thickness of the covering portion 21a is too thick, it is necessary to reduce the diameter of the core body 12b covered with the covering portion 21a, so that the mechanical characteristics (rigidity) of the cleaning portion 2 during insertion between the teeth is greatly reduced. In addition, Karman vortices are likely to occur during molding of the cleaning soft portion 21 and may be greatly affected by the Karman vortex. Since it cannot be filled, it is not preferable. For this reason, it is preferable to set the thickness of the covering portion 21a to 0.1 mm to 0.2 mm.

  The cleaning protrusions 21b are formed at intervals in the length direction of the covering portion 21a, and are disposed at intervals in the circumferential direction of the covering portion 21a. More specifically, a pair of cleanings projecting from the covering portion 21a to one side of the mold opening / closing direction in the circumferential direction of the covering portion 21a so as to be molded by the second molds 40 and 41 described later. Projecting portion 21b, a pair of cleaning projecting portions 21b projecting from the covering portion 21a to the other side in the mold opening and closing direction, and projecting from the covering portion 21a to one side along the mating surfaces 40a and 41a. There are a total of six types of cleaning protrusions 21b, one cleaning protrusion 21b and one cleaning protrusion 21b protruding from the covering portion 21a to the other side along the mating surfaces 40a and 41a. A plurality of types of cleaning protrusions 21b of a kind are formed at intervals in the length direction of the covering portion 21a. However, the cleaning protrusions 21b can be formed in an arrangement pattern other than those described above. For example, a set of four cleaning protrusions 21b projecting outward in a cross shape from the covering part 21a is pivoted. It is also possible to provide an interval in the direction.

The cross-sectional area, length, number, and arrangement interval of the base end portion of the cleaning projection 21b can be arbitrarily set, but the base end portion of the cleaning projection 21b is considered in consideration of moldability and cleanability. the cross-sectional area of ^preferably set to about 0.03 mm 2 1.5 mm ^2, the length of the cleaning projections 21b is preferably set to approximately 0.5 mm to 2.0 mm, cleaning projections The number of 21b is preferably set to 20 to 100, and the arrangement interval of the cleaning projections 21b is preferably set to 0.5 mm to 1.5 mm. Moreover, although the cone-shaped thing was employ | adopted as the projection part 21b for cleaning, the flat taper-shaped thing flat in an axial direction is also employable. Furthermore, as the cross-sectional shape of the cleaning projection 21b, an arbitrary cross-sectional shape such as an oval shape, a teardrop shape, or a polygon shape can be adopted in addition to a circular shape.

  By the way, when the soft portion 20 is molded, the core base material portion 12 is positioned in the central portion of the second molding space 42 by a plurality of holding pins 50 to 52 provided in the second molds 40 and 41 as will be described later. Cleaning to form a core base part recess 14a in the core base part 12 through the covering part 21a at a position corresponding to the holding pin in the cleaning part 2 of the interdental cleaning tool 1 for holding. A partial recess 14 is formed. The core base part recess 14a is softened when the relatively high temperature base part 10 immediately after being molded by the first molds 30 and 31 is exposed to the heat of the elastomer filled in the second molds 40 and 41. The tip of the holding pin comes into contact with the softened core base material portion 12.

  As shown in FIG. 6, the maximum depth d of the core base part recess 14 a from the outer peripheral surface of the core base part 12 is determined when the cleaning part 2 is inserted between the teeth or during interdental cleaning by the cleaning part 2. In order to prevent a large concentration of stress from occurring at the position where the core base material recess 14a is formed when a bending stress is applied to the cleaning part 2, the core base material part 12 is prevented from being bent. The range is set to 085 mm. In addition, when the resin composition which comprises the core base material part 12 contains a fibrous filler as a filler, especially glass fiber, it is the maximum depth from a viewpoint of balance of maintenance of a flexibility and improvement of a mechanical characteristic (rigidity). The thickness d is preferably 0.01 mm to 0.04 mm, more preferably 0.01 mm to 0.035 mm. When the resin composition includes a plate-like filler, particularly talc, the flexibility is maintained. And the maximum depth d is preferably 0.03 mm to 0.08 mm, more preferably 0.04 mm to 0.07 mm, from the viewpoint of balance between improvement of mechanical properties (rigidity). The maximum cross-sectional area of the core base material portion 12 at the position corresponding to the core base material portion recess 14a is 55% to 99% of the cross-sectional area of the core base material portion 12 at the position adjacent to the core base material portion recess 14a. .6 %%, preferably 80 to 97.9%, the stress concentration in the core base part recess 14a is reduced, and the core base part 12 is bent during insertion or cleaning between teeth. It is comprised so that can be prevented more effectively.

  The front shape of the cleaning portion recess 14 is formed in the same shape as the pin tip shape of the holding pin, for example, by forming the pin tip shape into a circular shape, an oval shape, a teardrop shape, a multi-shape such as a square or a rectangle, etc. The front shape of the recess 14 for cleaning can be made substantially the same shape. The oval shape includes, for example, shapes such as an oval, an oval, a rounded rectangle, a bowl, an oval, a chicken egg, and a rice bran. Polygonal shapes include squares, rectangles, and pentagons or more. The plurality of cleaning portion recesses 14 provided in the interdental cleaning tool 1 can be formed in the same shape, or can be mixed in any combination of different shapes depending on the distance from the tip of the cleaning portion 2 and the like. You can also.

  When the cleaning unit recess 14 is formed in an elongated shape such as an oval shape, a teardrop shape, or a rectangle, the rectangular cleaning unit recess 14A is adjacent in the circumferential direction as in the cleaning unit 2A shown in FIG. It is preferable to form between the cleaning protrusions 21b such that the longitudinal direction is the axial direction of the cleaning portion 2A. If comprised in this way, the width | variety of 14 A of cleaning part recessed parts will be narrowed, the holding | maintenance property of the holding | maintenance pin with respect to the core base material part 12 will be ensured sufficiently, reducing the width | variety of a holding | maintenance pin. Since the stress which generate | occur | produces in the position which provided this can be relieved, it is preferable.

  As shown in FIG. 6, the bottom surface of the core base portion recess 14a of the cleaning portion recess 14 is preferably formed of a flat surface in a direction orthogonal to the depth direction of the core base portion recess 14a. Like the core base part recess 14Ba of the cleaning part recess 14B shown, it is configured by an arc surface along the outer surface of the core base part 12, or like the core base part recess 14Ca of the cleaning part recess 14C shown in FIG. In addition, it can be constituted by two inclined surfaces having an isosceles triangular shape with a raised central portion.

The opening area of Shinmotozai section recess 14a is can be arbitrarily ^set, 0.08mm ^{2 ~0.35mm 2,} it is preferable that preferably set to 0.1mm ² ~0.25mm ^2. Further, the total area of Shinmoto material portion recess 14a formed in one interdental cleaner 1 is preferably set to 0.9mm ² ~1.3mm ^2. The opening area of the core base material recess 14a can be set to the same size, but is preferably set to be smaller as the core base material recess 14a on the tip side of the core base material 12 is smaller. The opening area of the core base material recess 14a refers to the core exposed in the core base material recess 14a with respect to the plane orthogonal to the center line DL (see FIG. 22) in the depth direction of the core base material recess 14a. It means the area surrounded by the projected figure of the boundary line between the base material part 12 and the cleaning soft part 21.

  A plurality of the cleaning unit recesses 14 are provided on the first side and the second side of the cleaning unit 2 at intervals in the axial direction of the cleaning unit 2. Here, the first side portion and the second side portion of the cleaning unit 2 are a part of the cleaning unit 2 molded by the second mold 40 and a part of the cleaning unit 2 molded by the second mold 41. This means the front surface side half and the back surface side half of the cleaning unit 2 corresponding to the front surface side and the back surface side of the flat handle base material portion 11.

  In the cleaning part 2 shown in FIGS. 5 and 6, the first side part and the second side part cleaning part recesses 14 face each other across the core base material part 12 and the depth direction is the second mold 40. A pair of cleaning portion recesses 14 arranged so as to be in the mold opening / closing direction of 41 and facing each other is set as one set, and three sets of cleaning portion recesses 14 are provided at intervals in the axial direction of the cleaning unit 2. It has been. It is preferable that the number of sets of the cleaning portion recesses 14 is two or more, preferably three or more. Thus, the bending stress which acts on the cleaning part 2 at the time of the insertion between teeth or the cleaning between teeth can be disperse | distributed by comprising the number of groups of the cleaning part recessed part 14 to 3 sets or more or 4 sets or more. In addition, as will be described later, by securing the holdability of the core base material portion 12 by the holding pins 50 to 52, by reducing the depth of the core base material portion recess 14a, it is locally large during interdental cleaning. It is possible to effectively prevent the core base material portion 12 from being bent due to the bending stress.

  The arrangement intervals of the cleaning unit recesses 14 with respect to the axial direction of the cleaning unit 2 may all be set to the same interval, but some or all of them may be set to different intervals. For example, the arrangement interval can be increased as it goes to the front end side of the cleaning unit 2. With this configuration, the arrangement space of the cleaning projection 21 b with respect to the front end side of the cleaning unit 2 can be increased. Since it becomes easy to ensure, it is preferable.

  The pair of cleaning portion recesses 14 are preferably arranged in a face-to-face manner, but within a range that partially overlaps in the circumferential direction, that is, within a range of the length of the cleaning unit recess 14 with respect to the axial direction of the cleaning unit 2. It can also be provided at a position shifted in the axial direction. Moreover, as shown in FIG. 6, although it is preferable to arrange | position the cleaning part recessed part 14 of a 1st side part, and the cleaning part recessed part 14 of a 2nd side part on the same axis line form, cleaning of the cleaning part 2D shown in FIG. As in the case of the concave portion 14D, the center line of the cleaning portion concave portion 14D on the first side and the central line of the cleaning portion concave portion 14D on the second side are shifted in parallel by a certain distance in the radial direction of the cleaning portion 2D. In this way, the cleaning portion recess 14D can be formed.

  Moreover, the arrangement | positioning position of the cleaning part recessed part 14 with respect to the cleaning part 2 can also be comprised as follows. However, the cleaning part recesses 14E and 14F and the core base part recesses 14Ea and 14Fa are different from the cleaning part recess 14 and the core base part recess 14a only in the formation position with respect to the cleaning part 2, and the front shape and depth A sheath opening area can be comprised similarly to the cleaning part recessed part 14 and the core base part recessed part 14a.

  1) Like the cleaning part recess 14E and the core base part recess 14Ea of the cleaning part 2E shown in FIGS. 11 and 12, counting from the cleaning part recess 14E on the first side part and the corresponding tip of the cleaning part 2E. The cleaning portion recesses 14E on the same second side can be formed at intervals in the axial direction of the cleaning portion 2E so as not to overlap in the circumferential direction of the cleaning portion 2E. In FIG. 11, the cleaning portion recess 14 </ b> E on the second side is disposed at a substantially central portion between the adjacent cleaning portion recesses 14 </ b> E on the first side, but the tip between the adjacent cleaning portion recesses 14 </ b> E on the first side. It can also comprise so that the cleaning part recessed part 14E of a 2nd side part may be arrange | positioned in the position biased to the side or the base end side. In addition, the cleaning unit recesses 14E on the first side and the cleaning unit recesses 14E on the second side are spaced apart from each other in the circumferential direction of the cleaning unit 2E in the axial direction of the cleaning unit 2E. The cleaning portion recess 14E on the first side and the corresponding cleaning portion recess 14E on the same second side counted from the tip of the cleaning portion 2E can be cleaned. It can also be formed with an interval in the axial direction of the cleaning part 2E so as not to overlap in the circumferential direction of the part 2E. Further, the number of the cleaning part recesses 14E on the first side part and the number of the cleaning part recesses 14E on the second side part are preferably the same number, but can also be different, for example, cleaning the first side part. The number of the concave portions 14E can be made one less than the number of the cleaning portion concave portions 14E on the second side portion.

  In this way, the core base portion recesses 14Ea are alternately formed on the first side portion and the second side portion of the core base portion 12, and a pair of core bases are formed at the same position in the axial direction of the core base portion 12. Since it can prevent that a material part recessed part is formed, the cross-sectional area of the core base material part 12 in the position corresponding to the core base material part recessed part 14Ea can be enlarged, and generation | occurrence | production of the bending of the core base material part 12 can be prevented. Further, when the core portion 12 is bent between the holding pins 50A to 52A (see FIG. 18) when the soft portion 20 is molded, the depth of the core portion recess 14Ea is hardly increased, and the core substrate is not formed. The cross-sectional area of the core base material portion 12 at the position corresponding to the partial recess 14Ea is increased, so that the core base material portion 12 can be prevented from being broken. Furthermore, since the distance between the holding pins 50A to 52A of the second mold 40 and the holding pins 50A to 52A of the second mold 41 with respect to the length direction of the core base 12 is shortened, the core base is stable. It becomes possible to hold it with good performance.

  2) Like the cleaning part concave part 14F and the core base part recessed part 14Fa of the cleaning part 2F shown in FIGS. 13 and 14, the second mold 40 is formed in a face-to-face manner with the core base part 12F interposed therebetween, The first side cleaning portion recess 14F and the core base portion recess 14Fa and the second side cleaning portion recess 14F so as to form an angle θ2 in the circumferential direction with respect to the mold opening / closing direction of 41 (see FIG. 20). And the core base-material recessed part 14Fa can also be arrange | positioned. However, the cleaning part recesses 14F and 14 on the first side and the second side part can also be formed shifted in the axial direction, similarly to the cleaning part recess 14E.

  In the cleaning unit 2F shown in FIG. 13, only the second set of cleaning unit recesses 14 from the tip of the cleaning unit 2 shown in FIG. 5 is replaced with the cleaning unit recess 14F, and the first and third ones from the tip of the cleaning unit 2F The individual is composed of the cleaning unit recess 14 arranged so that the depth direction is the mold opening / closing direction of the second molds 40 and 41, but one or a plurality of sets of cleaning unit recesses at arbitrary positions in the cleaning unit 2 14 can be replaced with a cleaning portion recess 14F.

  When the angle θ2 exceeds 60 °, the holding pins 62 (see FIG. 20) provided in the adjacent cleaning soft part molding portions 46 may interfere with each other, and therefore, the angle θ2 is 60 ° or less, preferably 45 ° or less. It is preferable to set. In addition, a concave portion for cleaning can be formed with an angle θ2 on the opposite side across a line segment in the mold opening / closing direction passing through the center of the cleaning portion 2F, or a plurality of types having different angles θ2 with respect to the cleaning portion 2F. A cleaning unit recess can also be provided.

  As described above, when the cleaning portion recess 14F is provided at a position at an angle θ2 with respect to the mold opening / closing direction, when the plurality of cleaning protrusions 21b protruding outward are formed on the cleaning soft portion 21, The degree of freedom of the layout of the cleaning projection 21b can be improved. In other words, the cleaning portion recess 14F is formed by the holding pin that holds the core base material portion 12 in the center portion of the second forming space 42, and the position of the holding pin 62 is set to the formation position of the cleaning protrusion 21b. Since it can be adjusted in the length direction and the circumferential direction with respect to the second molding space 42 so as not to interfere with each other, the degree of freedom of the layout of the cleaning projections 21b can be improved. Further, since the handle base material portion 11 is configured to be flat, when the handle base material portion 11 is picked by a finger and the space between the molars is cleaned, the cleaning portion 2 is substantially perpendicular to the surface including the handle base material portion 11. In the plane of (mold opening / closing direction), as shown by the phantom line in FIG. 2, the cleaning unit recess 14 </ b> F has a depth direction that forms an angle θ <b> 2 with respect to the mold opening / closing direction. Since it is arrange | positioned, it can prevent effectively that the core base material part 12F bend | folds starting from the cleaning part recessed part 14F.

<Manufacturing method>
Next, the manufacturing method of an interdental cleaning tool is demonstrated.
As shown in FIGS. 15 to 17, this interdental cleaning device manufacturing method is a base material for manufacturing the base material portion 10 by filling the first molding space 32 of the first mold 30, 31 with a synthetic resin material. After the part molding step and the base material part 10 molded by the first molds 30, 31 are loaded into the second molding space 42 of the second molds 40, 41, the second molding space 42 is filled with an elastomer material. And a soft part forming step for forming the soft part 20. The first molds 30 and 31 correspond to the first mold and the second mold of the first mold, respectively, and the second molds 40 and 41 correspond to the first mold and the second mold of the second mold, respectively. To do.

(Base part molding process)
In the base material portion molding step, as shown in FIG. 15, the base material portion 10 is manufactured by filling the first molding space 32 of the first molds 30 and 31 with a synthetic resin material. More specifically, as the first molds 30 and 31, a plurality of first molding spaces 32 composed of a core base material portion molding portion 32a and a handle base material portion molding portion 32b are formed in parallel, and adjacent handle bases are formed. A pair of connecting portion molding portions 35 communicating with the material portion molding portion 32 b are formed, and a runner 33 is formed on the proximal end side of the plurality of first molding spaces 32, and a plurality of first portions are formed through the gate 34. By using the molding space 32 communicating with the runner 33 and supplying the synthetic resin material to the runner 33, the plurality of first molding spaces 32 are filled into the plurality of first molding spaces 32 through the gates 34. 10 will be molded simultaneously. Then, a primary molded product 10 </ b> A having a plurality of base material portions 10, runner portions 37, gate portions 36, and connecting portions 13 is manufactured. In addition, although the base material part 10 can also be shape | molded one by one, while shape | molding the several base material part 10 simultaneously, productivity can be improved and the shape | molded runner part 37 is hold | maintained. It is preferable because a plurality of substrate parts 10 can be transferred simultaneously and workability can be improved. The gate 34 is formed on the base end portion of the first forming space 32 opposite to the core base portion forming portion 32a, more preferably, the core base portion forming the first forming space 32 than the connecting portion forming portion 35. If it is the base end side opposite to the portion 32a, it can be formed at an arbitrary position. However, if a side gate is formed as the gate 34 at the base end portion of the first molding space 32, the second die 40 is formed. , 41 when the primary molded product 10A is loaded, it is preferable because the risk of the gate portion 36 of the primary molded product 10A being sandwiched between the second molds 40, 41 can be reduced. In addition, a hot runner can be provided in the first mold 30, 31 in place of the runner 33 made of a cold runner. However, the first mold 30, 31 is large and the manufacturing cost is high. It is preferable to provide a runner 33 made of a cold runner. Further, since the plurality of base material parts 10 can be connected with stability by the runner part 37, when the primary molded product 10A is transferred to the second molds 40 and 41, the handling property of the primary molded product 10A can be improved. preferable. Further, if a pin gate having a cylindrical shape or a spindle shape and having a diameter of 0.1 to 1.5 mm is adopted as the gate 34, a cold runner can be adopted, and the molded product can be made compact by narrowing the interval between the gates 34. It is preferable because it is possible.

(Soft part molding process)
In the soft part molding step, as shown in FIGS. 16 and 17, after the primary molded product 10A molded by the first molds 30 and 31 is loaded into the second molding space 42 of the second molds 40 and 41, The soft material 20 is formed by filling the second molding space 42 with an elastomer material, and the interdental cleaning tool connector 5 in which a plurality of interdental cleaning tools 1 are arranged in parallel is obtained.

  First, the second molds 40 and 41 used in the soft part molding step will be described. The second molds 40 and 41 include a plurality of base material parts of the primary molded product 10A molded by the first molds 30 and 31. A plurality of second molding spaces 42 are formed at positions corresponding to 10, and fitting spaces 43, 44, 45 that fit the runner portion 37, the plurality of gate portions 36, and the connecting portion 13 of the primary molded product 10 </ b> A are provided. Is formed. Between the second molds 40, 41 and the base material part 10, a cleaning soft part molding part 46 surrounding the core base material part 12 is formed as a second molding space 42. Gates 47 are formed on the mating surfaces 40a and 41a with the second molds 40 and 41 on the front end side of the cleaning soft portion molding portion 46, respectively. The gate 47 is connected to a common runner 48 formed in the second molds 40, 41, and the elastomer material is supplied from the common runner 48 to the plurality of second molding spaces 42 through the plurality of gates 47. Has been. The diameter of the gate 47 is preferably set to 0.1 mm or more and 1.0 mm or less.

  The second molds 40 and 41 have a pair of distal-end-side holding pins 50 and a pair of intermediate-portions held in correspondence with the distal-end side portion, intermediate portion, and proximal-end portion of the cleaning soft portion molding portion 46, respectively. A pin 51 and a pair of base end side holding pins 52 are provided in a face-to-face manner, and these three sets of holding pins 50 to 52 are substantially orthogonal to the mating surfaces 40a and 41a of the second molds 40 and 41, respectively. In other words, the second metal molds 40 and 41 are provided so as to be movable in the mold opening and closing direction, and the core base material part 12 of the base material part 10 has these three sets of holding pins 50 to 50 as shown in FIG. 52 by projecting the tip of 52 into the cleaning soft part molding part 46 and sandwiching the core base material part 12 between the tip parts of the holding pins 50 to 52 of each set, It is configured to be positioned and held with high accuracy in the central portion.

  By the way, when the elastomer material is filled into the cleaning soft portion molding portion 46, the core base material portion 12 is exposed to the high temperature elastomer material and softens, and the tip of the holding pins 50 to 52 causes the core base material portion 12 to be softened. A core base material recess 14a is formed on the outer peripheral surface. The core base part recess 14a is formed when the cleaning part 2 is inserted into the interdental space or when the cleaning part 2 performs interdental cleaning when a bending stress acts on the cleaning part 2. In order to prevent the core base material part 12 from being broken due to a large stress concentration, the maximum depth d of the core base part recess 14a is set to the holding pins 50 to the core base material part 12. By adjusting the length of 52, it is set to 0.01 mm or more and 0.085 mm or less, preferably 0.01 mm or more and 0.065 mm or less.

  In addition, the cross-sectional areas of the cross-sections orthogonal to the axial direction of the tip portions of the holding pins 50 to 52 are substantially the same as each other, Small compared to the cross-sectional area. The intermediate portion holding pin 51 and the proximal end side holding pin 52 are substantially the same or configured so that the intermediate portion holding pin 51 is larger than the proximal end side holding pin 52. That is, since the passage area of the distal end portion of the cleaning soft portion molding portion 46 is reduced, the flow resistance of the elastomer material is set as small as possible by reducing the cross-sectional area of the distal end side holding pin 50 as much as possible. Suppressing the influence of the Karman vortex that is sometimes generated is preferable because it is possible to prevent defective filling of the elastomer material into the cleaning soft part molding portion 46 and to prevent excessive melting of the core base material portion 12. However, it is also possible to provide a plurality of intermediate holding pins 51 at intervals in the axial direction. In the present embodiment, the cross-sectional shape of the tip of the holding pins 50 to 52 is circular, but in order to further suppress the influence of Karman vortices during molding, in the length direction of the cleaning soft part molding part 46 It is also possible to form an elongated oval shape, a teardrop shape, a rectangular shape, or the like.

Tip-side holding pin 50 is provided in the range of 3mm toward the distal end 46a of the cleaning soft portion forming portion 46 toward the proximal end, a cross-sectional area is set to 0.03mm ² ~0.3mm ² Yes. The intermediate portion holding pin 51 is provided within a range of ± 10% of the length of the cleaning portion 2 in the axial direction around the middle point between the distal end side holding pin 50 and the proximal end side holding pin 52, and its cross-sectional area. It is set to 0.12mm ² ~1.2mm ^2. Further, the proximal retaining pin 52 is set from the proximal end of the cleaning soft portion molding portion 46 provided in the range of 6mm toward the distal end side, a cross-sectional area to 0.1mm ² ~1.1mm ² Has been. By setting these, it is expected that not only the core base material portion 12 is fixed during molding, but also the influence of Karman vortices generated during molding on the molded body is prevented.

  The front end surface of the holding pins 50 to 52 that contacts the core base material portion 12 is configured as a flat surface orthogonal to the axial direction of the holding pins 50 to 52 as shown in FIG. Like the holding pin 60 shown in (b), it is configured by an arcuate surface along the outer peripheral surface of the core base material portion 12 or is connected in an isosceles triangular shape like the holding pin 61 shown in FIG. It is also possible to configure with a pair of inclined surfaces, and when configured in this way, the contact area between the core base material portion 12 and the holding pins 60 and 61 is set large, This is preferable because the depth can be set shallow, the core base material portion 12 can be held in the center of the second molding space 42 with high accuracy, and the holdability of the core base material portion 12 can be improved. In addition, holding pins having different tip end surface shapes can be used in any combination.

  The pair of distal end side holding pins 50, the pair of intermediate portion holding pins 51, and the pair of proximal end side holding pins 52 are arranged in a face-to-face manner on the same axis line with the core base material part 12 interposed therebetween. At least one set of the holding pins 50 to 52 is shifted in the length direction of the cleaning soft part molding portion 46 by, for example, a length of 0.1 to 1.0 times the diameter of the proximal holding pin 52. Can be arranged. If the pair of holding pins 52 are arranged so as to be shifted in the longitudinal direction of the cleaning soft part forming portion 46 in this way, when the core base material portion 12 is held between the holding pins 52, Since the area of the holding pin 52 to be crimped is effectively increased, the core base material portion 12 can be held more firmly. Moreover, it can be expected to prevent the Karman vortex generated during molding from affecting the molded body.

  In the soft part forming step, as shown in FIG. 17 (a), a pair of front ends as shown in FIG. 17 (b) with the primary molded product 10A loaded in the second forming space 42 and the mold closed. The side holding pin 50, the pair of intermediate portion holding pins 51, and the pair of base end side holding pins 52 are projected into the cleaning soft portion molding portion 46, and these three sets of holding pins 50 to 52 are used. An elastomer material is injected and supplied to a plurality of gates 47 through a common runner 48 while holding the core base material portion 12, and the elastomer material is filled into the cleaning soft portion molding portion 46. At this time, the core base material portion 12 is softened by the heat of the elastomer material, and the core base material portion concave portion 14a is formed by the tip portions of the holding pins 50 to 52. The maximum depth of the core base material portion concave portion 14a is formed. Since d is set to 0.01 mm or more and 0.085 mm or less, preferably 0.01 mm or more and 0.065 mm or less, cleaning is performed when the cleaning unit 2 is inserted between the teeth or during interdental cleaning by the cleaning unit 2. When bending stress is applied to the portion 2, it is possible to prevent the core base material portion 12 from being broken due to a large stress concentration at the position where the core base material recess 14 a is formed. Further, since the cross-sectional area of the holding pin 50 is set smaller than the cross-sectional area of the holding pins 51 and 52, filling of the elastomer material from the distal end portion of the cleaning soft portion molding portion 46 to the proximal end side is performed. The contact area between the holding pins 50 to 52 and the core base material portion 12 can be increased while keeping the core base material portion 12 with high stability while being prevented from being inhibited as much as possible by 50 to 52, and the injection pressure varies somewhat. Even if it occurs, it is possible to prevent the bending of the core base material portion 12 and to accurately mold the cleaning soft portion 21 made of an elastomer material.

  Thus, after covering the base portion 10 with the soft portion 20, the runner portion 37 and the gate portion 36 made of synthetic resin are removed, and the runner portion 55 made of an elastomer formed by the runner 48 and the gate 47 and The interdental cleaning tool 1 is obtained by removing the gate portion 56.

  In addition, the arrangement | positioning position of the holding pins 50-52 with respect to the 2nd metal mold | dies 40 and 41 can also be comprised as follows.

  3) Like the holding pins 50A to 52A of the second molds 40 and 41 shown in FIG. 18, hold the holding pins 50A to 52A of the second mold 40 from the tip of the corresponding soft part molding part 46 for cleaning. The spacing in the center line direction of the cleaning soft portion molding portion 46 is set so as not to overlap the circumferential direction of the cleaning soft portion molding portion 46 with respect to the holding pins 50A to 52A of the second second mold 41 counted. It can be formed open. In FIG. 18, the adjacent holding pins 50 </ b> A to 52 </ b> A in the second mold 40 are arranged in the approximate center between the holding pins 50 </ b> A to 52 </ b> A of the second mold 41. The holding pins 50A to 52A of the second mold 40 may be arranged at positions deviated toward the front end side or the base end side between 50A to 52A. In addition, cleaning is performed so that all the holding pins 50A to 52A of the second mold 40 and all the holding pins 50A to 52A of the second mold 41 do not overlap in the circumferential direction of the cleaning soft part molding portion 46. It can also be formed with an interval in the length direction of the soft part molding part 46 for use, the same as the specific holding pin of the second mold 40 and the corresponding tip from the tip of the soft part molding part 46 for cleaning The holding pins of the second second mold 41 can also be formed at intervals in the length direction of the cleaning soft part molding part 46 so as not to overlap in the circumferential direction of the cleaning soft part molding part 46. Furthermore, the number of holding pins of the second mold 40 and the number of holding pins of the second mold 41 are preferably the same number, but can also be different, for example, as shown in FIG. One holding pin 52A of the mold 40 can be omitted, and the number of holding pins of the second mold 40 can be made one less than the number of holding pins of the second mold 41.

  As described above, when the holding pins 50A to 52A of the first mold 40 are arranged so as to be shifted in the axial direction with respect to the holding pins 50A to 52A of the second mold 41, compared to the case where the holding pins are arranged facing each other, Since the cross-sectional area of the core base material portion 12 at the position corresponding to the core base material portion recess 14Ea is increased, it is possible to prevent the core base material portion 12 from being broken. Further, when the soft core portion 21 for cleaning is molded, the core base material portion 12 is also bent between the holding pins 50A to 52A. The cross-sectional area of the core base material portion 12 at a position corresponding to 14Ea is increased, and the occurrence of breakage of the core base material portion 12 can be prevented. Furthermore, since the interval between the holding pins 50A to 52A with respect to the length direction of the core base material portion 12 is substantially shortened, the core base material portion 12 can be held with good stability.

  4) Like the holding pins 62 of the second molds 40 and 41 shown in FIG. 20, the axial direction is opposite to the mold opening / closing direction of the second molds 40 and 41 with the core base material 12 interposed therebetween. The holding pins 62 of the first mold 40 and the holding pins 62 of the second mold 41 may be arranged so as to make an angle θ2 in the circumferential direction. However, the holding pins 62 on the first side and the second side can also be formed shifted in the length direction of the cleaning soft portion molding portion 46, similarly to the holding pins 50A to 52A of FIG.

  For example, only the second set of holding pins from the tip of the cleaning soft part molding part 46 is replaced with the holding pin 62, and the first and third parts from the tip of the cleaning soft part molding part 46 are in the axial direction. Can be constituted by holding pins arranged so as to be in the mold opening / closing direction of the second molds 40, 41, but one or a plurality of sets of holding pins at arbitrary positions in the cleaning soft part molding portion 46 are held pins. It can also be replaced with 62.

  When the angle θ2 exceeds 60 °, it may interfere with the holding pin 62 provided in the adjacent cleaning soft part molding portion 46, and therefore it is preferably set to 60 ° or less, preferably 45 ° or less. The second molds 40 and 41 may be provided with a plurality of types of holding pins 62 having different angles θ2.

  As described above, when the holding pin 62 is provided at a position at an angle θ2 with respect to the mold opening / closing direction, the cleaning soft portion 21 is formed with a plurality of cleaning protrusions 21b protruding outward. The degree of freedom of the layout of the projections 21b for use can be improved. That is, the holding pin 62 is formed by the holding pin 62 that holds the core base material portion 12 at the central portion of the cleaning soft portion forming portion 46, and the position of the holding pin 62 is formed by the cleaning protrusion 21b. Since the cleaning soft portion molding portion 46 can be adjusted in the length direction and the circumferential direction so as not to interfere with the position, the degree of freedom of the layout of the cleaning projection 21b can be improved. Further, since the handle base material portion 11 is configured to be flat, when the handle base material portion 11 is picked by a finger and the space between the molars is cleaned, the cleaning portion 2 is substantially perpendicular to the surface including the handle base material portion 11. The holding base 62 is arranged so as to form an angle θ2 with respect to the opening and closing direction of the die, but the core substrate formed by the holding pin 62 is curved in the (die opening and closing direction) plane. It is possible to effectively prevent the core base material portion 12 from being broken starting from the partial recess 14Fa.

(Test Example 1)
This test example shows that the depth of the core base material recess can be changed by selecting the material constituting the base material. First, a model in which a steel pin having a diameter of 0.5 mm and a hemispherical tip is point-contacted with a load of 1 N on the surface of a plate-like sample of the same size and thickness made of materials having different elastic moduli shown in Table 1. Then, the amount of dent at the time of steel pin point contact of each plate-like sample in the model was determined using analysis software (trade name: SolidWorks Simulation, manufactured by SOLIDWARKS).
The elastic moduli of the resin compositions A to D shown below are tensile test results based on JISK 7161. The results are shown in Table 1. From Table 1, it is clear that the amount of dents when pressed by a pin differs depending on the material. Note that the load value of the steel pin employed in this test example is different from the contact pressure of the holding pin on the base material portion in the second mold when the interdental cleaning tool of the present invention is manufactured.

Resin composition A: Polypropylene 80% by weight, glass fiber 20% by weight
Resin composition B: polypropylene 70% by weight, glass fiber 30% by weight
Resin composition C: polypropylene 60% by weight, talc 40% by weight
Resin composition D: 70% by weight of polypropylene, 30% by weight of talc

(Test Example 2)
Next, an evaluation test of the interdental cleaning tool will be described.
As the interdental cleaning tool, a base material part made of the resin composition shown in Table 2 is manufactured on polypropylene, and the thickness of the covering part made of polystyrene elastomer is about 0 on the surface of the core body of the core base material part in the base material part. Examples 1 to 5 having a core base part recess having the maximum depth shown in Table 2 with the same configuration as the interdental cleaning tool 1 shown in FIG. ~ 2 interdental cleaning tools were prepared. In addition, the comparative example 1 used the polypropylene simple substance which does not contain a filler.

In addition, the interdental cleaning tool obtained above has a total length of 48 mm, a handle base material portion size of 15 mm (maximum width length) × 6.5 mm, and a cleaning portion 2 length size and diameter of 15 mm and 0.65 mm, respectively. The cleaning protrusion is provided with a cleaning protrusion in which cleaning protrusions are arranged in four directions. Further, in the first side portion and the second side portion of the cleaning portion, a total of three opening recesses (corresponding to the core base material recesses, hereinafter the same) were formed at intervals of about 5 mm in the axial direction. The opening area of the recess was about 0.20 mm ² .

  Further, as Comparative Example 3, an interdental cleaning tool having the same shape and dimensions as Example 1 was prepared, except that the same resin composition and polystyrene-based elastomer as Example 1 were used and no opening recess was provided.

  Using a compression tester (trade name: Autograph, manufactured by Shimadzu Corporation), the cleaning part of the interdental cleaning tool of Examples 1 to 5 and Comparative Examples 1 to 3 obtained above was inserted at an insertion angle of 50. It was inserted between the teeth of the first and second molars of the jaw model (Nissin Co., Ltd.) at an insertion speed of 200 mm / min. This insertion test was performed three times, and the state of the cleaning part of each interdental cleaning tool was visually observed and evaluated according to the following criteria. The results are shown in Table 2.

[Evaluation criteria]
Yes; In the three insertion tests, although the cleaning part was not broken (broken), the deformation of the cleaning part was recognized even once.
Impossible; fold (break) of the cleaning part was observed even once in the three insertion tests.

  From Table 2, a resin composition containing a filler selected from a fibrous filler and a plate-like filler is used, and the maximum depth of the core substrate recess formed in the core substrate portion is adjusted to a predetermined range. It can be seen that the cleaning part can be prevented from being bent during interdental insertion, and when the fibrous filler is used, the maximum depth of the core base part recess is within a predetermined range. In order to prevent the cleaning portion from being broken, adjusting the maximum depth of the concave portion of the core base material portion to a depth within a predetermined range when a plate-like filler is used. It turns out that it is effective.

In addition, the interdental cleaning tool of this invention contains the following modifications.
5) If there is a cleaning part recess that forms a core base part recess having a maximum depth of 0.01 mm or more and 0.085 mm or less and other recesses, a specific or all first side part including that is included. The cleaning portion recesses and the corresponding second side cleaning portion recesses can be formed at an interval in the axial direction of the cleaning portion so as not to overlap in the circumferential direction of the cleaning portion. If comprised in this way, at the time of shaping | molding of a soft part, a core base part recessed part will be alternately formed in the 1st side part and 2nd side part of a core base part, and it will be in the same position of the axial direction of a core base part. Since it is possible to prevent a pair of core base part recesses from being formed, the cross-sectional area of the core base part at the position corresponding to the core base part recesses is increased to prevent the core base part from being broken. it can. Moreover, since the core base material portion can be prevented from being deepened even when the core base material portion is bent between the holding pins during molding of the soft portion, the position corresponding to the core base material portion recess As a result, the cross-sectional area of the core base material portion becomes larger, and the occurrence of breakage of the core base material portion can be prevented. Furthermore, since the interval between the holding pins with respect to the length direction of the core base material portion is substantially shortened, the core base material portion can be stably held. In addition, in this specification, the cleaning part recessed part of the 2nd side part corresponding to the cleaning part recessed part of the 1st side part means the same cleaning part recessed part counted from the front-end | tip of a cleaning part.

  6) The first side and the second side including the cleaning part concave part forming the core base part concave part having a maximum depth of 0.01 mm or more and 0.085 mm or less and the other concave parts, if any. A central line segment in the depth direction passing through the center of at least one set of cleaning section recesses among a plurality of sets of cleaning section recesses paired with the section in the mold opening / closing direction of the mold for molding the cleaning soft section On the other hand, it can also be formed with an angle in the circumferential direction of the cleaning part. If comprised in this way, when forming the some cleaning projection part which protrudes outward in the soft part for cleaning, the freedom degree of arrangement | positioning layout of this projection part for cleaning can be improved. That is, the cleaning portion recess is formed by the holding pin that holds the core base material portion in the center portion of the second molding space, but the position of the holding pin does not interfere with the formation position of the cleaning protrusion. Since it can adjust to a length direction and a circumferential direction with respect to 2nd shaping | molding space, the freedom degree of arrangement | positioning layout of this cleaning projection part can be improved.

  7) At least one of the plurality of cleaning portion recesses including a cleaning portion recess that forms a core base portion recess having a maximum depth of 0.01 mm to 0.085 mm and other recesses. One can also be formed in an elongated shape elongated in the axial direction of the cleaning portion. When the diameter of the concave portion of the cleaning portion is reduced, the holding pin forming the concave portion of the cleaning portion is reduced in diameter, the contact area of the holding pin with respect to the core base material portion is reduced, and the concave portion of the core base material portion tends to be deepened. Stress concentration is likely to occur at the position where the material portion recess is provided. When configured as in the present invention, the width of the concave portion of the cleaning portion is reduced, and the width of the holding pin is reduced, thereby improving the degree of freedom of the layout of the cleaning projections and holding the core base portion. It is preferable because the contact area of the pins can be increased to reduce the depth of the core base portion recess, and the stress concentration at the position where the core base portion recess is provided can be effectively prevented.

  8) At least one of a fiber material and talc can be added to the synthetic resin material constituting the base material portion. By comprising in this way, the strength rigidity with respect to the bending stress of a core base-material part can be improved, and the insertion property of the cleaning part with respect to between teeth can be improved. Moreover, since the rigidity of the core base material portion can be increased, the depth of the recess formed in the core base material portion is difficult to increase, and the occurrence of stress concentration at the position where the core base material recess is provided is prevented. However, it is preferable.

  The manufacturing method of the interdental cleaning tool of the present invention includes a base part made of a resin composition containing a synthetic resin and a specific filler, and a soft part made of an elastomer covering at least a part of the base part. The base material portion has a handle base material portion and an elongated shaft-shaped core base material portion connected to the tip end portion of the handle base material portion, and the soft portion is a soft cleaning material that covers the core base material portion. A method of manufacturing an interdental cleaning tool that has at least a portion, a handle base portion that forms a handle portion as a handle, and a core base portion and a cleaning soft portion that form an interdental cleaning portion. In addition, the resin composition is supplied to the first molding space of the first mold, and the base material part molding step for molding the base material part, and the base material part molded in the base material part molding process, the soft part The first mold and the second mold of the second mold are loaded in the second molding space of the second mold for molding the mold and spaced apart in the length direction of the second molding space. Each of the holding pins provided with two or more pins is brought into contact with the core base material portion, and an appropriate load is applied to the core base material portion so that the core base material portion is substantially at the center of the soft part for cleaning. The soft part which fills the elastomer in the second molding space and molds the soft part while forming the core base part recess having the maximum depth of 0.01 mm or more and 0.085 mm or less in the core base part. A molding process.

  In the manufacturing method of this interdental cleaning tool, since the maximum depth of the core base part recess formed in the core base part is set to 0.01 mm or more and 0.085 mm or less, 2 The core base material portion can be stably held with respect to the appropriate position in the molding space, the molding accuracy of the interdental cleaning tool can be improved, and the core base material portion is crossed at the formation position of the core base material recess. Sufficient area can be secured to prevent stress concentration at the portion, and the core base material can be prevented from being bent during insertion between teeth or during interdental cleaning. Note that the maximum depth of the concave portion of the core base material portion can be adjusted by adjusting the length of the holding pin or by adjusting the length of the holding pin in addition to adjusting the load applied to the core base material portion by the holding pin tip as described above. It can be adjusted to a desired depth by exchanging it with a different one.

  Here, the maximum cross-sectional area of the core base material portion at the position corresponding to the core base material portion recess is 55% to 99.6% of the cross-sectional area of the core base material portion at a position adjacent to the core base material recess. It is preferable to set to 80.0% to 97.9%, and it is a more preferable embodiment. If comprised in this way, the stress concentration in a core base-material part recessed part will be decreased, and the breakage of the core base-material part at the time of insertion between teeth and the cleaning between teeth can be prevented much more effectively.

  In a preferred embodiment, the first mold holding pin and the second mold holding pin of the second mold are provided in a face-to-face manner with the core base material portion interposed therebetween. Here, the term “face-to-face” means that a straight line connecting portions where the tip portions of the holding pins to be in contact with each other passes through the vicinity of the axial center of the core base material portion. In this case, the core base material portion can be held with high stability by the plurality of holding pins with respect to the central portion of the second molding space.

  In a preferred embodiment, at least one of the first mold and the second mold of the second mold is provided with three or more holding pins. If comprised in this way, since the 3 or more cleaning part recessed part is formed in the at least one side part of the 1st side part and 2nd side part of a cleaning part with a holding pin, it is the interdental produced by this manufacturing method. The cleaning tool can disperse and absorb the bending stress acting on the cleaning part at the time of insertion between teeth or between teeth at three or more cleaning part positions where the cleaning part recesses are formed. It is possible to effectively prevent the core base material from being bent due to the large bending stress. In addition, when three or more holding pins are provided, the contact area of the holding pins with respect to the core base material portion can be increased, and the vibration of the core base material portion during molding of the soft portion can be suppressed. Since it can suppress that depth becomes deep, since generation | occurrence | production of the stress concentration of the position of the core base-material recessed part at the time of interdental cleaning can be prevented effectively, it is preferable. In addition, the 1st type | mold and 2nd type | mold holding pin in a 2nd metal mold | die can also be set to the same number, and can also be set to a different number. When the first-type holding pins and the second-type holding pins are arranged facing each other, they are set to the same number. However, the first-type holding pins and the second-type holding pins are arranged in the second molding space. When the arrangement positions are shifted in the length direction, the number of both can be set differently. For example, the number of holding pins can be reduced by only one for the first type than for the second type. it can.

  The interval between the holding pins with respect to the length direction of the second molding space is preferably substantially the same, but may be set so as to become narrower toward the distal end side of the second molding space.

  It is also a preferred embodiment that the area of the tip of the holding pin located at the most tip of the cleaning part is set to be substantially the same as or smaller than the area of the tip of the holding pin at other positions. That is, the passage area of the second molding space for molding the cleaning soft portion becomes narrower toward the tip side. For this reason, by reducing the area of the tip of the holding pin as in the present invention, the cross-sectional area of the entire holding pin can also be reduced, so that the passage area can be set as large as possible, and the flow resistance of the elastomer material can be reduced as much as possible. In addition to being able to be set small, it is possible to further suppress the influence of Karman vortex moldings and holding pins that occur in the vicinity of each holding pin, to improve the holding of the core base material part, and the elastomer material to the soft part molding part for cleaning Filling failure can be prevented.

  In addition, it is also possible to provide the above-described method for manufacturing an interdental cleaning tool according to the present invention by arbitrarily combining the following configurations.

  9) The elastomer material can be filled from the distal end side of the second molding space, or the elastomer material can be filled from the proximal end side of the second molding space.

  10) In the case where there is a holding pin that forms a concave portion of the core base material having a maximum depth of 0.01 mm or more and 0.085 mm or less and other holding pins, All the holding pins of the first mold and the corresponding holding pins of the second mold are formed at intervals in the length direction of the second molding space so as not to overlap in the circumferential direction of the second molding space. You can also. When comprised in this way, a core base part recessed part is alternately formed in the 1st side part and 2nd side part of a core base material part, and a pair of core base material is the same position of the axial direction of a core base material part. Since it can prevent that a part recessed part is formed, the cross-sectional area of the core base part in the position corresponding to a core base part recessed part can be enlarged, and generation | occurrence | production of the bending of a core base part can be prevented. In addition, since the core base material portion can be prevented from being deepened by bending the core base material portion between the holding pins when the soft portion is molded, The cross-sectional area of the core base material portion at the corresponding position is increased, and the occurrence of breakage of the core base material portion can be prevented. Furthermore, since the interval between the holding pins with respect to the length direction of the core base material portion is substantially shortened, the core base material portion can be stably held. In addition, the 2nd type | mold holding pin corresponding to a 1st type | mold holding pin means the same holding pin counted from the front-end | tip of 2nd shaping | molding space, for example.

  11) When there is a holding pin that forms a core base portion recess having a maximum depth of 0.01 mm or more and 0.085 mm or less and other holding pins, including the holding pin, the first mold in the second mold, A center line segment of at least one holding pin of the plurality of sets of holding pins paired with the second die is arranged in the circumferential direction of the second molding space with respect to the die opening / closing direction of the second die. It can also be formed at an angle. If comprised in this way, when forming the some cleaning projection part which protrudes outward in the soft part for cleaning, the freedom degree of arrangement | positioning layout of this projection part for cleaning can be improved. In other words, the soft portion is molded with the core base material portion held at the central portion of the second molding space by the plurality of holding pins, but the position of the holding pin does not interfere with the forming position of the cleaning protrusion. Thus, since it can adjust to a length direction and a circumferential direction with respect to 2nd shaping | molding space, the freedom degree of arrangement | positioning layout of this cleaning projection part can be improved.

  12) At least one of a fiber material and talc can be added to the synthetic resin material constituting the substrate portion. By comprising in this way, the strength rigidity with respect to a stress can be improved at the bending of a core base-material part. In addition, since the rigidity of the core base material portion can be increased, it is preferable to reduce the depth of the core base material recess to prevent the occurrence of stress concentration at the position where the core base material recess is provided.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and it goes without saying that the configuration can be appropriately changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Interdental cleaning tool 2, 2A, 2D, 2E, 2F Cleaning part 5 Interdental cleaning tool coupling body 10 Base material part 10A Primary molded article 11 Handle base material part 12, 12F Core base material part 13 Connection part 14, 14A, 14B, 14C, 14D, 14E, 14F Cleaning part recess 14a, 14Aa, 14Ba, 14Ca, 14Ea, 14Fa Core base part recess 20 Soft part 21 Cleaning soft part 21a Covering part 21b Cleaning protrusion 30, 40, 41 Gold Mold 32, 42 Molding space 32a Core base part molding part 32b Handle base part molding part 33, 48 Runner 34, 47 Gate 35 Connecting part molding part 36, 56 Gate part 37, 55 Runner part 43 Fitting space 46 For cleaning Soft part molding part 50, 50A, 51, 51A, 52, 52A, 60, 61, 62 Holding pin 100 Synthetic resin

Claims (6)

A base part made of a synthetic resin, and a soft part made of an elastomer covering at least a part of the base part,
The base material part has a handle base material part to be a handle, and an elongated shaft-shaped core base material part connected to a tip part of the handle base material part,
The soft part has at least a soft part for cleaning that covers the core base part,
An interdental cleaning tool comprising a cleaning part for interdental cleaning with the core base material part and the soft cleaning part,
The synthetic resin constituting the base material part is a resin composition containing a synthetic resin and at least one selected from a fibrous filler and a plate-like filler, and the cleaning part includes a first side part and a first side part. 2 side portions, each of the first side portion and the second side portion penetrating the soft portion for cleaning, and having a maximum depth of 0.01 mm to 0.085 mm on the surface of the core base material portion. the cleaning portion recess leading to Shinmotozai portion recess, at intervals in the axial direction of the cleaning unit possess two or more,
The shaft portion covered with the cleaning soft part of the core base part is composed of a distal-side core body and a proximal-side core body connected thereto, and the diameter of the distal-side core body is 0.4 mm to 0.6 mm. , and the and interdental cleaning tool the diameter of the proximal-side core body and said 0.8mm~2mm der Rukoto.   The plurality of core base part recesses on the first side and the plurality of core base part recesses on the second side are respectively arranged in a face-to-face manner with the core base part interposed therebetween. The interdental cleaning tool according to 1. The interdental cleaning tool according to claim 1 or 2 , wherein the fibrous filler is at least one selected from the group consisting of glass fiber, wollastonite, and potassium titanate fiber. The interdental cleaning tool according to any one of claims 1 to 3 , wherein the plate-like filler is at least one selected from the group consisting of glass flakes, mica, talc, and clay. The interdental cleaning tool according to any one of claims 1 to 4 , wherein a blending amount of the filler is 10 to 50% by weight of the total amount of the resin composition. The interdental cleaning tool according to any one of claims 1 to 5 , wherein the synthetic resin is a thermoplastic resin having a melting point of 150 ° C or higher.

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