JP2019118798A - Interdental cleaning tool - Google Patents

Abstract

An object of the present invention is to provide an interdental cleaning tool having a core base portion, particularly a cleaning portion, which is hard to break during interdental cleaning, has good durability, and is excellent in insertability into the interdental portion. The interdental cleaning tool includes an elongated shaft-shaped core base portion, and inserts the core base portion into the interdental portion to clean the interdental portion, wherein the core base portion is , a resin composition containing a thermoplastic resin and an inorganic filler, wherein the thermoplastic resin has a weight average molecular weight of 400,000 or more, preferably a weight average molecular weight of 400,000 or more, and a number average molecular weight of 78,000. An interdental cleaning tool that is the above. [Selection drawing] Fig. 1

Description

  The present invention relates to an interdental cleaner.

 The interdental cleaning tool is widely used to prevent dental caries and periodontal disease, for example, by removing food plaque caught in the interdental area and plaque that causes tartar, which tends to adhere mainly to the roots of teeth. It is used. As an interdental cleaning tool, for example, an elongated shaft-like core base portion, a handle base portion continuously connected to one end of the core base portion, and a soft portion covering the surface of the core base portion The interdental cleaning tool provided has been put to practical use (see Patent Documents 1 to 3). Hold the handle base of the interdental cleaning tool with your finger, insert the core base covered with the soft part into the interdental part, and reciprocate mainly in the axial direction to make plaque and food cake Remove and massage gums and gums to relieve inflammation.

Patent No. 4236571 Patent No. 3002668 gazette Japanese Patent Publication No. 2001-506514

  In the conventional interdental cleaning tool including the interdental cleaning tool described in Patent Documents 1 to 3, the core base portion is made of synthetic resin, and the soft portion in direct contact with the interdental portion is made of synthetic resin It is common to be composed of soft elastomers. Thermoplastic resins are mainly used as the synthetic resin constituting the core substrate portion from the viewpoint of mechanical properties, flexibility, mass productivity and the like. Moreover, in order to further improve the mechanical property of a thermoplastic resin, the resin composition which mix | blended the inorganic filler which has predetermined | prescribed shapes, such as fibrous form and flake shape, may be used. Hereinafter, the core base portion and the soft portion covering the surface thereof are collectively referred to as a “cleaning portion”.

  As a reason for improving the mechanical properties of the synthetic resin that constitutes the core base portion, for example, it can be mentioned that the elongated shaft-shaped core base portion is easily broken due to the force applied to the cleaning portion at the time of interdental cleaning. For example, when the cleaning portion is inserted into the interdental portion, a large compressive force acts on the axial direction of the cleaning portion. In addition, when cleaning the molars (especially molars) and the interdental area on the back of the front teeth on the mandible side, the cleaning section inserted into the interdental area has its middle part from the tip to the axial center of the interdental cleaning tool Because a large bending force acts on the cleaning portion, the cleaning portion is moved in and out in a curved state of 60 ° to 90 °. For this reason, even in the core base portion made of a synthetic resin having high mechanical properties, breakage of the core base portion and the cleaning portion, deformation without recovery, and the like occur relatively frequently at the time of interdental cleaning.

  Heretofore, it has been recognized that since the core base portion is formed into an extremely thin diameter that can be inserted into the interdental portion, the core base portion apparently has sufficient flexibility and elasticity. And, in order to prevent the core base portion from being broken, it has been considered necessary to increase the mechanical strength of the synthetic resin constituting the core base portion rather than the enhancement of the flexibility and elasticity. . For this reason, as a measure to prevent the core base portion from being broken, it has been mainly practiced to form the core base portion with a resin composition obtained by adding an inorganic filler such as glass fiber to a synthetic resin such as polypropylene resin. The

  The inventors focused on the viscosity of the synthetic resin as a property leading to the flexibility and elasticity of the synthetic resin, contrary to the conventional technical common sense, in the research process of preventing breakage of the core base portion, and the viscosity of the synthetic resin Further studies have been conducted on the relationship between the and the breakage of the core substrate portion.

  An object of the present invention is to provide an interdental cleaning tool which is hard to break at the time of cleaning between teeth, has good durability, and is excellent in insertability into the interdental region.

Means of Solving the Problems The present invention provides, as a preferred embodiment, the following interdental cleaner of (1) to (10).
(1) An interdental cleaning tool comprising an elongated shaft-like core base part and inserting the core base part into the interdental part to clean the interdental part, wherein the core base part is thermoplastic An interdental cleaner comprising a resin composition containing a resin and an inorganic filler, wherein the weight average molecular weight of the thermoplastic resin is 400,000 or more.
(2) The interdental cleaner of (1), wherein the thermoplastic resin has a weight average molecular weight of at least 400,000 and a number average molecular weight of at least 78,000.
(3) The interdental cleaning tool according to the above (1) or (2), wherein the thermoplastic resin has a weight average molecular weight of 420,000 or more and a number average molecular weight of 80000 or more (4) The thermoplastic resin is an olefin The interdental cleaning tool according to any one of the above (1) to (3), which is at least one selected from the group consisting of a system resin, a polyamide system resin, and a polyester system resin.
(5) The interdental cleaning tool according to any one of the above (1) to (4), wherein the thermoplastic resin is an olefin resin and the olefin resin is a propylene resin. .
(6) The interdental cleaning tool according to any one of (1) to (5), further including a handle base portion connected to one end of the core base portion.
(7) The interdental cleaning tool according to any one of (1) to (6), further comprising a soft part made of a material softer than the resin composition and covering the surface of the core base part.
(8) The interdental cleaning tool according to any one of the above (1) to (7), wherein the resin composition further comprises an elastomer compatible with a thermoplastic resin.
(9) The interdental space according to (8), wherein the elastomer is at least one thermoplastic elastomer (TPE) selected from the group consisting of styrenic elastomers, olefinic elastomers, vinyl chloride elastomers, and amide elastomers. Cleaning tool.
(10) Any one of the above (1) to (9), wherein the inorganic filler is at least one selected from the group consisting of fibrous inorganic fillers, flaky inorganic fillers, and particulate inorganic fillers. Interdental cleaning tool.

In the present specification, both the number average molecular weight and the weight average molecular weight are polystyrene equivalent values measured by GPC (gel permeation chromatography) method of polystyrene standard. For this measurement, for example, using a GPC apparatus and a GPC column, detection with a differential refractometer under the conditions of measurement solvent: o-dichlorobenzene, oven temperature: 135 ° C., sample concentration: 0.2% (w / v) It is done by doing. As a GPC apparatus, brand name: HLC-8121GPC / HT (made by Tosoh Co., Ltd.) and brand name; Prominence GPC system (made by Shimadzu Corp.) can be used, for example. Moreover, as a GPC column, brand name: Shodex GPC HT-806M (made by Showa Denko KK) can be used, for example.

  The interdental cleaning tool according to the present invention is resistant to breakage of the core base portion during interdental cleaning, has good durability, and is excellent in insertability into the interdental portion.

It is drawing which shows typically the external appearance of one form of the interdental cleaning tool of this embodiment. It is drawing which shows typically the external appearance of the other form of the interdental cleaning tool of this embodiment. It is a side view which shows the test method of the fatigue test in a bending fatigue test. It is a side view which shows the test method of the cantilever bending test in a bending fatigue test. It is a graph which shows the result of a bending fatigue test.

  The interdental cleaning tool according to the present embodiment has a long, narrow, shaft-like core base part inserted into the interdental part to clean it, and the core base part is a thermoplastic resin having a weight average molecular weight of 400,000 or more. It is comprised from the resin composition containing resin and an inorganic filler. That is, in the present embodiment, a resin composition containing a thermoplastic resin having a weight average molecular weight of 400,000 or more and an inorganic filler is used as a material constituting the core base portion. The interdental cleaning tool according to the present embodiment is not particularly limited as long as it has the core base portion, and various conventionally known modes can be adopted.

  For example, the interdental cleaning tool according to the first embodiment includes the core base portion. For example, the proximal end of the core base portion may be gripped with a finger. If the proximal end side of the core base portion is gripped with fingers, the tip end portion of the core base portion can be easily inserted into and removed from the interdental portion. Further, the core base portion may be provided with a shaft-like or plate-like support portion provided with an insertion mechanism capable of attaching and detaching the proximal end of the core base portion. Here, the support portion may have the same shape and dimensions as the handle base portion described later except that a mechanism (or structure) capable of attaching and detaching the proximal end of the core base portion is provided. The mechanism (or structure) is, for example, a hole into which the proximal end of the core base portion is inserted, a fitting mechanism, a screw mechanism, or the like. In the fitting mechanism and the screw mechanism, both of the proximal end of the core base portion and the mechanism provided on the support portion have predetermined structures.

  The interdental cleaning tool of the second embodiment has a core base portion and a handle base portion connected to one end of the core base portion. The interdental cleaning tool of the third embodiment has a core base portion, a handle base portion connected to one end of the core base portion, and a soft portion that covers the surface of the core base portion. The interdental cleaning tool according to the fourth embodiment includes a core base portion, a handle base portion continuously connected to one end of the core base portion, a soft portion covering the surface of the core base portion, and a soft portion surface And one or more projections projecting outward from the projection. The soft part has a single or a plurality of protrusions on the surface, for example, from the viewpoint of enhancing the cleaning function of the interdental part and the massage function of the gingival part. The protrusion is preferably made of the same material as the soft portion from the viewpoint of ease of molding and the like. When a plurality of protrusions are provided, the arrangement may be regular or irregular, and the three-dimensional shape of the protrusions may be the same or different. In the interdental cleaning tool of the third and fourth embodiments, the soft portion can cover a part or the whole of the surface of the core base portion. Moreover, in the interdental cleaning tool of the fourth embodiment, the protrusion may be provided on the entire surface of the soft part, or may be provided on part of the soft part such as the tip that reciprocates the interdental part. The interdental cleaner of the present invention is not limited to the first to fourth embodiments, and may include the form of a conventionally known interdental cleaner.

  The core base portion, the core base portion coated with the soft portion, and the core base portion coated with the soft portion having projections on the surface are all inserted into the interdental portion, and reciprocated in the axial direction By moving it, it has a function to remove food plaques and plaques which are pinched between interdental parts, and a function to massage the gums. Hereinafter, the core base portion covered with the soft portion or the soft portion having the protruding portion is also referred to as a “cleaning portion”. The core base portion or the cleaning portion is supported by holding the handle base portion with fingers. In a state where the handle base portion is gripped with a finger, the core base portion or the cleaning portion is inserted into the interdental portion, and the interdental portion is cleaned by reciprocating in the axial direction to perform gum massage.

  The inventors of the present invention, in the process of preventing breakage of the core substrate portion, among thermoplastic resins having a weight average molecular weight of 400,000 or more, preferably a weight average molecular weight of 400,000 or more and a number average molecular weight of 78,000. The above-noted matter is focused not only on mechanical properties and rigidity but also on viscosity, as compared with thermoplastic resins of relatively low molecular weight. Then, as a result of further researches, the present inventors made it possible to prevent the core base portion formed into a specific shape of a shaft having an extremely thin diameter from breaking of the core base portion. It was found that it is important not only to have mechanical properties and rigidity but also to have a predetermined viscosity or more. That is, the durability of the core substrate as a very thin shaft against the compressive force of the synthetic resin from the tip direction of the core substrate and the bending force from the direction perpendicular to the axial direction of the core substrate. It became clear from the research of the present inventors that the fracture resistance is improved by

  The viscosity here is not tackiness, and is considered to be, for example, a characteristic such as viscoelasticity that raises the threshold when the core substrate breaks in the direction intersecting the axial direction. As a result of using a thermoplastic resin having a weight average molecular weight of 400,000 or more, the interdental cleaning tool of the present embodiment does not substantially impair the insertability of the core base portion into the interdental portion, the core base portion It is possible to significantly reduce breakage during interdental cleaning, and the durability is improved.

  The core base portion is considered to have apparently sufficient flexibility and / or elasticity because it is formed by molding a thermoplastic resin into an elongated shaft shape. In the conventional core base portion, the compressive force from the tip end direction of the core base portion or the bending force from the direction perpendicular to the axial direction of the core base portion is easily or easily broken when externally applied. It has been considered that the core base portion has the above-mentioned apparent elasticity and / or flexibility, so that the threshold value of mechanical characteristics that can withstand these forces is low. And in order to raise the said threshold value, adding inorganic fillers, such as glass fiber, to a thermoplastic resin, and raising mechanical strength is performed. That is, it has been considered that there is no particular correlation between the flexibility and elasticity of the material constituting the core base portion and the bending resistance of the core base portion. However, according to the studies of the present inventors, it has been found that not only the mechanical properties of the material constituting the core base portion but also the flexibility, elasticity and viscosity are involved in the bending resistance of the core base portion.

  The details of the interdental cleaning tool of the present embodiment are as follows. The structure of the core base portion and the material constituting the core base portion will be described.

  The elongated shaft-like core base portion is a member common to the interdental cleaner in the first to fourth embodiments and the other embodiments. For example, as shown in FIG. 1, the core base material portion of the present embodiment has a form in which the axis extends substantially straightly (for example, an inter-I-tooth cleaning tool), a form in which the axis is curved from the middle to the tip As shown in the figure, the entire shaft is curved from the root (hereinafter also referred to as “base end”) connected to the handle base portion to the distal end (for example, curved interdental cleaning tool), predetermined from the middle of the shaft Formed into a linear shape (for example, an L-shaped interdental cleaning tool) with a taper angle, a form with a tapered tip, a gradually tapering shape that decreases in diameter toward the tip The form includes a form in which the diameter is gradually increased from the middle part of the core base to the side held by the finger with the finger or to the side of the support or the handle base. The interdental cleaner shown in FIGS. 1 and 2 is included in the interdental cleaner of the third embodiment.

  The core base portion is formed in an elongated shaft shape and contains a thermoplastic resin having a weight average molecular weight of 400,000 or more (hereinafter sometimes referred to simply as “thermoplastic resin” unless otherwise specified), and an inorganic filler, It consists of a resin composition (A) which may contain an elastomer. Furthermore, the resin composition (A) can contain the well-known additive contained in the thermoplastic resin composition for interdental cleaning tools.

  The thermoplastic resin in the resin composition (A) has a weight average molecular weight of 400,000 or more, and preferably a weight average molecular weight of 400,000 or more, and a number average molecular weight from the viewpoint of the bending resistance of the core substrate portion. The molecular weight is 78,000 or more, more preferably the weight average molecular weight is 420,000 or more, and the number average molecular weight is 80000 or more, still more preferably the weight average molecular weight is 450,000 or more, and the number average molecular weight is 85,000 or more It is. In addition, although the upper limit of a weight average molecular weight and a number average molecular weight can be made into the value which can be injection-molded, respectively, if an example is given, a weight average molecular weight is 600,000 or less or 650,000 or less, and a number average molecular weight is It is less than 120,000 or less than 150,000.

  As the thermoplastic resin, any thermoplastic resin commonly used in the field of interdental cleaning tools can be used without particular limitation as long as the thermoplastic resin has a weight average molecular weight of 400,000 or more, and, for example, olefin resin and polyamide resin And polyester resins, polymethyl methacrylate, cellulose propionate, thermoplastic polyurethane resins, polycarbonate resins, polyacetal resins, ABS (acrylonitrile butadiene styrene) resins and the like, and one or two of them may be mentioned. You can use the above. Among these thermoplastic resins, those having a predetermined weight average molecular weight or a predetermined weight average molecular weight and a predetermined number average molecular weight may be selected and used. The number average molecular weight and / or the weight average molecular weight can be easily adjusted by those skilled in the art, for example, by selecting the degree of polymerization, the monomer component, the polymerization method and the like.

  Among the above-mentioned thermoplastic resins, from the viewpoint of improving the bending resistance of the core base portion, the molding processability, the mechanical properties and the like, it is selected from the group consisting of olefin resins, polyamide resins and polyester resins. Or at least one of the foregoing is preferred, and an olefin resin is more preferred. Specific examples of the olefin-based resin include, for example, propylene-based polymers (homopolymers, random copolymers, block copolymers), ethylene-based polymers (homopolymers, random copolymers, block copolymers) and the like. Moreover, as a specific example of polyester-type resin, saturated polyester-type resin, such as a polyethylene terephthalate, a polybutylene terephthalate, a polytrimethylene terephthalate, polycyclohexylene dimethylene terephthalate, is mentioned, for example.

  Among the above-mentioned olefin resins, a propylene polymer (or a propylene resin) is more preferable from the viewpoint of preventing the breakage of the core base portion and the cleaning portion, the molding processability and the economy, and the melting point Is more preferably 150.degree. C. or more and at least a part of which is crystalline. The propylene-based polymer is particularly preferable because the molding temperature is low, the cycle time can be shortened to improve the productivity, and the heat load on the molding equipment is small. When a thermoplastic resin having a melting point of 150 ° C. or more is used as the material of the interdental cleaning tool, the molding time of the intermediate molded product (core base and the handle base connected to it) is shortened, particularly the cooling time after molding Production efficiency can be improved. As a result, it is possible to improve the productivity of the interdental cleaning tool of the present embodiment, reduce the production cost, and the like.

  The propylene-based polymer (or propylene-based resin) contains at least one selected from the group consisting of homopolymers (propylene homopolymers), random copolymers and block copolymers, as described above. The random copolymer is a copolymer of propylene and a compound copolymerizable therewith, and includes, for example, a copolymer of propylene and an α-olefin. The copolymer of propylene and an α-olefin is, for example, a copolymer of propylene and ethylene and / or an α-olefin having 4 to 12 carbon atoms, which contains 50% by weight or more of a structural unit derived from propylene. And preferably a propylene-ethylene random copolymer. As a block copolymer, a propylene ethylene block copolymer etc. are mentioned, for example. Similarly, the ethylene-based polymer is a homopolymer of ethylene, a random copolymer of ethylene and an α-olefin having 4 to 12 carbon atoms, a block copolymer and the like.

  As the inorganic filler in the resin composition (A), a fibrous inorganic filler (hereinafter also referred to as "fibrous filler"), a flaky inorganic filler (hereinafter also referred to as "flaky filler"), and granules At least one selected from the group consisting of inorganic fillers (hereinafter also referred to as "particulate fillers") can be preferably used. The shapes of these inorganic fillers can be identified by microscopic observation with a scanning electron microscope.

  The fibrous filler is an inorganic compound having a long dimension (long dimension) in one direction. The shape is called a columnar or whisker shape other than fibrous, and the length dimension is in the order of mm to μm, and the diameter of the fiber is mainly in the order of μm. The aspect ratio (fiber length / fiber diameter) of the fibrous filler is preferably 2 or more, more preferably 5 or more, and still more preferably 10 or more. The fibrous filler is not particularly limited, but glass fibers, wollastonite, titanium dioxide fibers, potassium titanate fibers and the like can be preferably used from the viewpoint of safety and availability for the human body, and further, the viewpoint of price etc. In consideration, glass fibers and wollastonite are more preferable, and glass fibers are more preferable. The fibrous filler is preferable to the flaky filler from the viewpoint of enhancing the rigidity of the core base portion, in particular, the rigidity in the axial direction of the core base portion. The fibrous fillers may be used alone or in combination of two or more.

  The flaky filler is an inorganic compound having a thin dimension (thickness dimension) in one direction. The shape is also called scale-like or plate-like in addition to flaky shape, and the dimension is on the order of μm. The flaky filler is not particularly limited, but in view of safety to human body, availability, etc., for example, glass flakes, mica, clay, talc and the like are preferable, clay and talc are more preferable, and talc is more preferable. The flaky filler can be used singly or in combination of two or more.

  The particulate filler is an inorganic compound having a regular shape such as a substantially spherical shape or a substantially elliptical shape, or an irregular shape, which does not belong to a fibrous or flaky shape by microscopic observation. Although the dimension is in the range of μm order to mm order, it is preferable to have the dimension of μm order when applied to the core base portion of the present embodiment. The particulate filler is not particularly limited, and examples thereof include calcium carbonate, barium sulfate, silica, fused silica, zeolite, aluminum hydroxide, titanium oxide and the like. The particulate filler may be used alone or in combination of two or more.

  As a preferable form of an inorganic filler, single use of a fibrous filler, combined use with a fibrous filler and a flaky filler, etc. are mentioned. When the fibrous filler is used alone, the bending resistance of the core base portion or the cleaning portion is remarkably improved by the cooperation of the fibrous filler and the thermoplastic resin having a predetermined weight average molecular weight. In the combined use of the fibrous filler and the flaky filler, since the orientation directions of the fibrous filler and the flaky filler in the core base portion are different, the core can be selected by appropriately selecting the ratio of use thereof. In some cases, mechanical properties and flexibility (elasticity) of the base portion can be made compatible at a high level, which may contribute to the improvement of the bending resistance of the core base portion. Specific examples of the combined use include, for example, combined use of glass fiber and talc, and the like.

  In the resin composition (A), the content of the inorganic filler is not particularly limited. For example, 5 to 40% by weight, 10 to 40% by weight, and 20 to 40% by weight of the total amount of the thermoplastic resin and the inorganic filler % Or 25 to 38% by weight, with the balance being thermoplastic resin. When the content of the inorganic filler is within the above range, the bending resistance of the core base portion is improved by the cooperation with the thermoplastic resin. If the content of the inorganic filler is too small, the insertability of the core base to the interdental part may be reduced, and the improvement of the bending resistance of the core base may be insufficient. . When the content of the inorganic filler is too large, the dispersibility of the inorganic filler in the resin composition (A) may be reduced, and the local reduction in the bending resistance may occur in the core base portion. In the present invention, a commercially available compound in which an inorganic filler such as glass fiber is blended with a thermoplastic resin having a number average molecular weight of 400,000 or more can be used.

  The elastomer which is an optional component contained in the resin composition (A) is not particularly limited, and styrene-based, olefin-based, vinyl chloride-based, polyamide-based thermoplastic elastomer (TPE), silicone-based, urethane-based, The thermosetting elastomers, such as a fluorine-type, etc. are mentioned. In particular, an elastomer compatible with the thermoplastic resin in the resin composition (A) constituting the core base portion is preferable, and an elastomer compatible with the olefin resin is more preferable. The elastomer compatible with the olefin resin is preferably the above-described thermoplastic elastomer, more preferably a styrene-based or olefin-based elastomer, and still more preferably a styrene-based elastomer. The elastomer can be used singly or in combination of two or more.

  The content of the elastomer in the resin composition (A) is an amount by which the bending resistance of the core base portion is improved according to the type of the thermoplastic resin and the inorganic filler, each content, the type of the elastomer itself, and the like. It may be selected appropriately and is not particularly limited. When the content of the elastomer is an appropriate amount, the above-described effects of the present embodiment (improvement of the bending resistance of the core base portion, remarkable improvement of the feeling of use, occurrence of warpage in the core base portion equivalent portion of the intermediate molded product) And the like) can be obtained. When the content of the elastomer is too small, the improvement of the bending resistance of the core substrate by the addition of the elastomer becomes insufficient, and when the content of the elastomer is too large, to the interdental part of the core substrate or the cleaning part There is a tendency for the insertability and the feeling of use of the Therefore, it is easy to select the content of the elastomer by preliminary experiments and the like.

  As a specific example of the content of the elastomer, for example, in the resin composition of one embodiment containing a propylene-based polymer, a thermoplastic elastomer and a glass fiber, the total amount of the propylene-based polymer and the glass fiber is 100 parts by weight The blending amount of the thermoplastic elastomer can be 30 parts by weight or less, 25 parts by weight, 20 parts by weight or less, 15 parts by weight or less, or 10 parts by weight or less. Since the elastomer is an optional component, there is no need to set the lower limit. For example, the lower limit is 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 3 It may be in parts by weight or 5 parts by weight. In addition, these numerical ranges may be applicable also when using inorganic fillers other than a propylene polymer and thermoplastic resins having a number average molecular weight of 400,000 or more and / or glass fibers.

  In this embodiment, a thermoplastic resin having a number average molecular weight of less than 78000, which is compatible with a thermoplastic resin having a number average molecular weight of 78000 or more, as long as the bending resistance of the core base portion is not impaired Can be contained in

  The axial dimension (diameter) and the length dimension of the core base portion of the present embodiment are not particularly limited, but from the viewpoint of facilitating the operation of the interdental cleaning tool as a whole, for example, the axial dimension (diameter) is 0.3 mm The length dimension is selected from the range of -2 mm or 0.4 mm to 2 mm, and selected from the range of 20 to 75 mm or 20 to 50 mm. Moreover, in the form which made the front-end | tip part of the core base material part tapered, the axial dimension of a front-end | tip part is selected from the range of 0.3 mm-0.6 mm, for example, Axial dimensions other than a front-end part are 0.8 mm-2 mm Select from the range. When the core substrate portion curves from the middle or the root, the angle (a virtual axis when assuming that the core substrate portion extends linearly, and a position at which the vertical line lowered to the virtual axis in the curved portion is the longest An angle formed by a straight line connecting the boundary positions of the core base portion and the handle base portion in the imaginary axis can be appropriately selected according to the design of the interdental cleaning tool.

  The handle base portion used in the interdental cleaning tool according to the second to fourth embodiments and the other embodiments holds the core base portion while supporting the core base portion while holding the handle base portion with a finger. It is inserted into the interdental area for cleaning. Therefore, from the viewpoint of the bonding strength between the handle base portion and the core base portion, the handle base portion is preferably integrally molded with the core base portion. The handle base integrally molded with the core base portion The material portion is composed of the resin composition (A) as in the core substrate portion. However, the present invention is not limited to this, and the handle base portion may be made of a resin material other than the resin composition (A). In the present specification, the core base portion and the handle base portion may be collectively referred to as a base portion.

  The three-dimensional shape of the handle base portion of the present embodiment may be a shape that is commonly used in the field of interdental cleaning tools, as long as the shape can be easily grasped with a finger. is there. The cross-sectional shape of the shaft-like handle base portion is, for example, circular, oval (elliptical, oval, rounded rectangular, oval, oval, wedge, etc.), teardrop, polygon, rounded A square etc. are mentioned. The length dimension of the handle base portion in the axial direction (axial direction of the core base portion), the length dimension in the width direction perpendicular to the axial direction, and the thickness dimension are not particularly limited. 10 mm to 25 mm, length dimension in the width direction of 4 mm to 10 mm, thickness dimension (axis diameter dimension in the case of an axial shape) of 0.5 mm to 3 mm can be appropriately selected.

  The soft portion used in the interdental cleaning tool of the third to fourth embodiments and the other embodiments has, for example, a tip portion inserted into the surface of at least a portion of the core base portion or the interdental portion of the core base portion And is made of a material softer than the resin composition (A) (hereinafter also referred to simply as "soft material"). The soft material is not particularly limited. For example, the first form comprising a resin composition (A) in which the content of the elastomer is increased and the content of the inorganic filler is decreased, for example, from a mixture of a thermoplastic resin and an elastomer And the fourth form consisting of a single type or two or more types of elastomer, the fourth form consisting of a single type or two or more types of rubber, and the fifth form consisting of a mixture of an elastomer and a rubber. Here, as the rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, isoprene rubber, peptile rubber, ethylene propylene rubber, acrylonitrile butadiene rubber, silicone rubber, fluoro rubber, acrylic rubber, urethane rubber, polysulfide rubber, chlorinated butyl rubber, Examples thereof include synthetic rubber such as shrimp chlorohydrin rubber and natural rubber.

  The thermoplastic resin used in the soft material of the second embodiment is at least one member selected from the thermoplastic resin contained in the resin composition (A), or an olefin resin and a polyamide resin, or an olefin resin, or It is a propylene-based polymer. The elastomer is an elastomer contained in the resin composition (A), an elastomer requiring compatibility with a thermoplastic resin, an elastomer having compatibility with an olefin resin, a styrenic elastomer, an olefin elastomer, a vinyl chloride elastomer, At least one thermoplastic elastomer selected from the group consisting of amide based elastomers, or styrenic elastomers.

  The elastomer used in the third and fifth embodiments of the soft material is not particularly limited, and may be a styrene-based, olefin-based, vinyl chloride-based, polyamide-based thermoplastic elastomer (TPE), silicone-based, urethane-based, The thermosetting elastomers, such as a fluorine-type, etc. are mentioned.

  In the interdental cleaning tools of the third to fourth embodiments, when the core base portion is made of the resin composition (A1) containing an elastomer, the elastomer contained in the soft material of the first to third and fifth embodiments is The elastomer different from the elastomer in the resin composition (A1) can be an elastomer softer than the elastomer in the resin composition (A1). By configuring in this manner, the hardness (softness at the time of use) of the surface of the soft part is independently emphasized, and the feeling of use becomes further excellent.

  The soft portion made of the soft material of the first to fifth embodiments may cover the entire surface of the core base portion, but may cover a predetermined region from the tip portion to the middle portion of the core base portion. preferable. Specifically, for example, it is preferable to cover the range of 10 mm to 25 mm or 12 mm to 22 mm from the tip of the core base portion with the soft portion. The thickness of the soft portion is selected, for example, from the range of 0.05 mm to 0.5 mm, 0.1 mm to 0.3 mm, or 0.1 mm to 0.2 mm.

Further, in the soft section which is made of the first to fifth (or third or fourth) soft materials and has a plurality of protrusions standing on the surface, which is used for the interdental cleaning tool of the fourth embodiment, A plurality of projections are provided spaced apart from each other in the longitudinal direction and the circumferential direction of the soft portion. Sectional area of the soft portion surface of the protrusion, for ^example, selected from the range of 0.03 mm 2 1.5 mm ^2. The height of the projection from the surface of the soft portion is, for example, selected from the range of 0.5 mm to 4.0 mm. The number of protrusions in the soft portion is, for example, selected from the range of 20 to 100, but may be smaller or larger than the above range. The distance between one protrusion and the other protrusion adjacent thereto is selected from, for example, the range of 0.5 mm to 1.5 mm, but may be smaller or larger than the range described above. The three-dimensional shape of the protrusion is not particularly limited, and examples thereof include a conical shape, a pyramidal shape, a cylindrical shape, a prismatic shape, and an axially flat plate shape and a tapered shape. Moreover, as a cross-sectional shape of a projection part, circular shape, oval shape, teardrop shape, polygonal shape etc. are mentioned.

  Further, the soft part of another form covers the entire surface of the core base part, and the side of the core base part connected to the handle base part is a coated soft part having no protrusion on the surface, A protruding soft portion having a protrusion on the surface can be made from the end opposite to the handle base portion to the tip of the core base portion. The soft part of this form can be used for the interdental cleaning tool of the 3rd-4th embodiment.

  As described above, in the interdental cleaning tool of the present embodiment, at least the core base portion is made of the resin composition (A), and the structural features of the core base portion and the interdental cleaning tool are particularly good. There is no limitation. As a specific example of the interdental cleaning tool, the interdental cleaning tool 1 or 2 shown in FIGS. The interdental cleaning tools 1 and 2 respectively include core base portions 10A and 10B made of the resin composition (A), and handle base portions 11A and 11B connected to one end of the core base portions 10A and 10B. Between teeth of 4th Embodiment which has soft part 12A, 12B which coat | covers the surface of core base-material part 10A, 10B, and several projection part 13A, 13B which protrudes outward from the soft part 12A, 12B surface. It is a cleaning tool. In any of the interdental cleaning tools, since the core base portions 10A and 10B are made of the resin composition (A), the bending resistance of the core base portions 10A and 10B is significantly improved, and the interdental teeth It is also excellent in insertability. The interdental cleaning tool 1 has a core base portion 10A extending in one direction, and the interdental cleaning tool 2 has a core base portion 10B that curves and extends.

  The interdental cleaning tool of this embodiment is manufactured, for example, by two-color molding using the resin composition (A) and the first and second dies for forming the conventional interdental cleaning tool. More specifically, for example, the resin composition (A) is melt-kneaded, and the obtained melt-kneaded product is supplied into the first molding die to form an intermediate molded product (for example, the core base portion and the like) An interdental cleaning tool according to a second embodiment of the present invention, which comprises a handle base portion, and the intermediate molded product is mounted in a second molding die, if necessary, in any of the first to fourth embodiments. By supplying the melt-kneaded product of the soft material into the second molding die, the interdental cleaner of the third to fourth embodiments having the soft portion on the surface of the core base portion can be obtained. In addition, when obtaining the interdental cleaning tool of 1st-2nd embodiment, it is not necessary to implement 2-color shaping | molding, and it can manufacture also by 1-time shaping | molding.

  In the interdental cleaning tool according to the present embodiment (the first to fourth embodiments and the other embodiments), for example, a plurality of interdental cleaning tools, in which a plurality of interdental cleaning tools are releasably connected one by one in the width direction It may be in the form of a collection of cleaning tools, or it may be in a form in which a plurality of interdental cleaning tools are stored in a container or a bag in a disjointed state (individually independent state).

(Test Example 1)
An evaluation test of the interdental cleaning tool was conducted.
[Preparation of interdental cleaning tool]
A polypropylene resin having the following number average molecular weight and weight average molecular weight was prepared.
(A) Weight average molecular weight 458000, number average molecular weight 87700
(B) Weight average molecular weight 565000, number average molecular weight 111000
(C) weight average molecular weight 427000, number average molecular weight 85000
(D) Weight average molecular weight 406000, number average molecular weight 85200
(E) Weight average molecular weight 349000, number average molecular weight 73200
(F) Weight average molecular weight 397000, number average molecular weight 75 900

  Dry blending of each of the above polypropylene resins (a) to (f) and glass fiber or talc as an inorganic filler, the content of glass fiber or talc is 15 to 30% by weight of the whole, and the balance is as described above A resin composition which is a polypropylene resin having predetermined weight average molecular weight and number average molecular weight was produced.

  Using each resin composition obtained, the length of 48 mm, the dimension of the handle base portion is 15 mm (maximum width) × 6.5 mm, and the side of the core base portion connected to the handle base portion is the first shaft portion The second shaft portion is from the end of the first shaft portion on the side away from the handle substrate portion to the tip of the core substrate portion. The dimensions of the first shaft portion are 18 mm in length and 1.2 mm in diameter. The second shaft portion had a tapered shape in which the diameter gradually decreased toward the tip end, and the diameter of the tip portion was 0.45 mm. The polystyrene-based elastomer was coated over the entire circumference of the core base portion to form a soft portion having a thickness of 0.2 mm. In addition, a protrusion was not formed in the part which covers the 1st axial part of a soft part, but several projections (cone-shaped 1 mm in height) were provided in the part which covers a 2nd axial part. Thus, the interdental cleaning tool of the third embodiment was produced.

Each obtained interdental cleaning tool was subjected to the following evaluation test. The test results are shown in Table 1.
[90 ° bendable number of times test]
(1) The handle base portion of the interdental cleaning tool is held between a pair of fixing tools, and the interdental cleaning tool is vertically supported so that the tip of the cleaning section faces upward in the vertical direction. Let the root of the cleaning part be the fulcrum of bending.
(2) Bending the tip of the cleaning portion in one direction by 90 ° and maintaining for 3 seconds. This operation is one count.
(3) After returning the front end of the cleaning unit, bend it in the other direction by 90 ° and maintain it for 3 seconds. This operation is one count. In addition, it adjusts so that one direction of (2) and the other direction here may become substantially on a straight line.
(4) The operations of (2) and (3) are alternately repeated to count the number of counts until the cleaning unit breaks or is not returned.
(5) This test is carried out ten times, the count number of each time is arithmetically averaged, and the value obtained by rounding off the second decimal place is shown in Table 1. In Table 1, Mw represents a weight average molecular weight, and Mn represents a number average molecular weight. Moreover, let polypropylene resin be PP resin.

[Vertical bending test strength]
The interdental cleaning tool and the compression jig are disposed such that the tip of the cleaning portion of each interdental cleaning tool obtained is directed upward, and the front end vertically contacts the compression jig. Then, a compression test was performed with an autograph (manufactured by Shimadzu Corporation) at a compression speed of 10 mm / min to measure the maximum strength when the cleaning portion was torn and broken. In the test, five samples were measured at each level, and the arithmetic mean value was taken as the vertical bending strength of the interdental cleaning tool. The results are shown in Table 1.

[Bending fatigue test]
The bending fatigue property of the cleaning part was evaluated by the following test. After applying the fatigue test of the following (A) to each inter-tooth cleaning tool obtained in Examples 1-5 and Comparative Examples 1-4, the cantilever bending test of the following (B) was implemented.

(A) Fatigue test (1) A model of the fatigue test shown in FIG. 3 was prepared. Install a testing machine 30, install a shallow jig storage case 35 with a bottom open at the top below the testing machine 30, and place three cylindrical jigs with a diameter of 10 mm on the bottom of the jig storage case 35. The teeth were held side by side and fixed, and an interdental model 33 was produced. The handle base portion 21 of the interdental cleaning tool 20 is held and fixed by the two lower ends 32 of the tester 30, and the tip of the cleaning portion 22 of the interdental cleaning tool 20 to the lower end 32 of the tester 30. The interdental cleaning tool 20 is suspended in the vertical direction so that the length of the cleaning part 22 is 35 mm and the area 5 mm from the tip of the cleaning part 22 abuts on the cylindrical jig 31 in the middle of the interdental model 33 .
(2) The tester 30 was rotated to the left in the drawing to fix the interdental cleaning tool 20 at the position A at 45 ° left with respect to the vertical direction.
(3) After rotating the interdental cleaning tool 20 from the position A to the position B at 45 ° right in the vertical direction by rotating it from the state of (2) to the right in the drawing, rotate the tester 30 to the left in the drawing, The interdental cleaning tool 20 was returned to position A. The movement from position A to position B and position B to position A of the interdental cleaning tool 20 was one cycle, and was repeated a predetermined number of times. The rotational speed of the tester 30 was 30 ± 3 cycles / minute.

(B) Cantilever bending test The test apparatus 40 shown in FIG. 4 was used. The test apparatus 40 includes a fixing jig 41, a fulcrum jig 42, and a pressing device 43. The fixing jig 41 is provided upright on the support plate 50, and supports the interdental cleaning tool 20 in the horizontal direction so that the cleaning portion 22 of the interdental cleaning tool 20 is exposed. The fulcrum jig 42 is a square pillar-shaped member whose cross-sectional view in the longitudinal direction orthogonal to the width direction is a triangular shape whose acute angle is an acute angle. The fulcrum jig 42 has its apex (or ridge line = sharp angled tip) 51 abuts on the lower surface at a position 7 mm from the tip of the cleaning portion 22 of the interdental cleaning tool 20 fixed by the fixing jig 40. As such, they are provided to project from the support plate 50. The pressing device 43 is supported by a support member (not shown) so as to move up and down, and presses the position 3 mm from the top of the cleaning portion 22 of the interdental cleaning tool 20 fixed by the fixing jig 41 from above The pressure applied to 22 is provided to be able to be displayed as a numerical value. In this test, the descent speed of the pressure device 43 was 20 mm / min.

The inter-tooth cleaning tool 20 (hereinafter referred to as the "implemented item") for which the inter-tooth cleaning tool 20 (hereinafter referred to as the "un-performed item") of the above-mentioned fatigue test is not implemented 4), the pressure immediately before the cleaning part 22 breaks or bends unrecoverably (load pressure on the cleaning part 22 by the pressurizing device 43) is measured, and the cleaning The strength of the part 22 was used. And the intensity | strength maintenance factor (%) with respect to the unimplemented goods of the implemented goods was computed from the following formula. In addition, for the practical product, the strength retention rate was determined for each of the above (i) and (3) implemented three, five and ten times, and the results are shown as a graph in FIG. 5, and The results of those carried out 10 times are shown in Table 1 below.
Strength maintenance ratio of the implemented product (%) = (Strength of the implemented product / Strength of the unimplemented product) × 100

[Bearing resistance and interdental insertability by repeated use]
Ten expert panelists evaluated the bending resistance and the interdental insertability by repeated use of the interdental cleaning tools thus obtained to the entire intraoral area of the oral cavity. The evaluation criteria by each expert paneler are as follows.

<Evaluation criteria for breakage resistance by repeated use>
... ... 5 or more times of repeated use ... ... 3 to 4 times of repeated use × ... Break at 1 time use

<Evaluation criteria for interdental insertability>
... ... No occurrence of bending at the time of insertion with 10 panelists ○ ... 3 or less occurrence of bending at the time of insertion with 10 panelists × ... 5 or more occurrence of bending at the time of insertion with 10 panelists

  It can be seen from Table 1 that when a polypropylene resin (PP resin) having a weight average molecular weight of less than 400,000 is used, the bending resistance of the core base portion, particularly the cleaning portion, is very low. When a polypropylene resin having a weight average molecular weight of 400,000 or more is used, the bending strength in the vertical direction (N) and the number of times of 90 ° bending (times) are obtained in addition to the significant improvement in the bending resistance. It can be seen that the respective properties such as the bending fatigue property of the cleaning portion and the interdental insertability are improved, and in particular, the improvement of the interdental insertability is remarkable.

1, 2, 20 interdental cleaning tool 10A, 10B core base 11A, 11B, 21 handle base 12A, 12B soft part 13A, 13B protrusion 22 cleaning part 30 tester 31 cylindrical jig 32 lower end of tester Part 33 Interdental model 35 Jig storage case 40 Testing device 41 Fixing jig 42 Support jig 43 Pressurizer 50 Support plate 51 Support jig apex (tip)

Claims (10)

An interdental cleaning tool comprising an elongated shaft-like core base part, and inserting the core base part into an interdental part to clean the interdental part,
The interdental cleaning tool, wherein the core base portion is made of a resin composition containing a thermoplastic resin and an inorganic filler, and the weight average molecular weight of the thermoplastic resin is 400,000 or more.   The interdental cleaning tool according to claim 1, wherein the thermoplastic resin has a weight average molecular weight of 400,000 or more and a number average molecular weight of 78,000 or more.   The interdental cleaning tool according to claim 1 or 2, wherein the thermoplastic resin has a weight average molecular weight of 420,000 or more and a number average molecular weight of 80000 or more.   The interdental cleaning tool according to any one of claims 1 to 3, wherein the thermoplastic resin is at least one selected from the group consisting of an olefin resin, a polyamide resin, and a polyester resin.   The interdental cleaning tool according to any one of claims 1 to 4, wherein the thermoplastic resin is an olefin resin and the olefin resin is a propylene resin.   The interdental cleaning tool according to any one of claims 1 to 5, further comprising a handle base portion connected to one end of the core base portion.   The interdental cleaning tool according to any one of claims 1 to 6, further comprising a soft portion which is made of a material softer than the resin composition and covers the surface of the core base portion.   The interdental cleaning tool according to any one of claims 1 to 7, wherein the resin composition further comprises an elastomer compatible with the thermoplastic resin.   The interdental cleaning according to claim 8, wherein the elastomer is at least one thermoplastic elastomer (TPE) selected from the group consisting of styrenic elastomers, olefinic elastomers, vinyl chloride elastomers, and amide elastomers. Equipment.   The tooth according to any one of claims 1 to 9, wherein the inorganic filler is at least one selected from the group consisting of fibrous inorganic fillers, flaky inorganic fillers, and particulate inorganic fillers. Cleaning tool between.

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