JP2005103184A - Toothbrush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothbrush capable of visually displaying the degraded state of bristles before the bristles are torn or bent under repeated use, regardless of the open state of bristle tips in the toothbrush using PTT (polytrimethylene terephthalate) bristles. <P>SOLUTION: This toothbrush using the PTT bristles for a part or the whole of bristles inserted in a head part insertion face. The PTT bristle 10 is formed in double or triple sheath core structure comprising a core part 11 and sheath parts 12, 13, for instance. A region different in color or depth of color is formed in at least a part of the cross section of the PTT bristle 10 so that the color or depth of color of the bristle surface, or the area of the part different in color or depth of color taking up the bristle surface, is changed by wear caused by repeated use. Further, a boundary part changed in color or depth of color is set to a depth of 1-7.5% of a bristle radius from the bristle surface, and the region different in color or depth of color exists within 3 mm at least from the bristle tip. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toothbrush using a brush made of polytrimethylene terephthalate (PTT) resin.

  Generally, a synthetic resin such as nylon resin (6-12 nylon, 6-10 nylon) or polybutylene terephthalate (PBT) resin is used for the brush of a toothbrush, and some natural hair such as pig hair is used. Is still used.

  In contrast, recently, a toothbrush using a monofilament (hereinafter referred to as PTT hair) made of polytrimethylene terephthalate (PTT) resin as a polyester resin excellent in durability of a toothbrush flocked portion (see Patent Documents 1 to 3). However, since the raw material is expensive, a toothbrush in which PTT hair is implanted is not commercially available at present. However, in recent years, inexpensive raw materials have been supplied, and toothbrushes in which PTT hairs have been implanted have come to a practical level in terms of cost. The PTT resin is sometimes called a polypropylene terephthalate (PPT) resin because of its molecular structure.

  On the other hand, if the brush color changes due to the wear of the brush and the toothbrush replacement time can be informed, the pork is used for the brush and some or all of the pork is colored or unbleached or the degree of bleaching is adjusted. A toothbrush (see Patent Document 4) that can be discolored or faded by brushing, saliva, or toothbrushing. The brush is a multi-layer composite polymer structure with at least two layers of different colors, and each layer The color density of the colored portion changes due to the use of a toothbrush (see Patent Document 5) having a color difference value ΔE of 3 or more and the brush constituting the material, and the color of the colored portion or the change in the color density is a brush. A toothbrush that acts as a signal to notify the wear of the brush (see Patent Document 6), the brush cross section has at least a three-layer structure, the outermost layer is a transparent layer, and the inner layer has a color and / or color And toothbrush bristles were the brush that the colored layer consisting of two layers different (see Patent Document 7) are known of.

JP-A-8-173244 (full description, drawings) International Publication No. 01/75200 pamphlet (full description and drawings) Japanese translation of PCT publication No. 2001-511379 (full description, drawings) Japanese Utility Model Publication No. 56-92518 (full description, drawings) Japanese Utility Model Publication No. 59-77430 (full description, drawings) Japanese Laid-Open Patent Publication No. 2-152406 (the full description and drawings) Japanese Unexamined Patent Publication No. Hei 6-277118 (full description and drawings)

  The present inventors conducted an experiment on the opening durability of the hair in a toothbrush. Thickness on toothbrush handle in which circular flocking holes with a diameter of 1.6 mm are arranged in the head part (tip 2 holes + 3 holes x 7 rows, vertical hole pitch: 2.6 mm, horizontal hole pitch; 2.2 mm) Using a brass metal piece (flat wire) of 0.25 mm and brushing about 19 brushes (monofilaments) with a diameter of 0.203 mm (8 mils) in three folds per hole, Fabricate toothbrushes that are cut flat with a cutter so that the length (hair length from the head flocking surface) is 9.5 mm, and fix these toothbrushes to a model durability tester, and the opening durability of the brushes by brushing Was measured.

  In addition, as a brush material, three types of PTT hair, PBT hair, and nylon hair (6-12 nylon) are prepared, and PTT hair having a hot water shrinkage (JIS L 1013: 1999) of 0.2% is used. For PBT hair and nylon hair (6-12 nylon), general-purpose products generally used for toothbrushes were used.

  This model durability tester is fixed on a corrugated metal plate so that the flocked surface of the toothbrush head part faces in parallel, and is wiped in a direction perpendicular to the corrugated wave in warm water at 35 ° C. The test conditions were as follows: while applying a load of 300 g per toothbrush head, brushing was performed up to 10,000 times at a brushing speed of 150 rpm and a brushing stroke of 40 mm, and the hair at the flocked part was opened at 5,000 times and 10,000 times. The rate was measured.

  Here, the open ratio of the hair is the difference between the width of the flocked portion at the tip of the hair before the brushing (perpendicular to the longitudinal direction of the handle) and the width of the flocked portion after the brushing test. Divided by part width and expressed in%.

  As a result of the experiment, as shown in Table 1, it was confirmed that the PTT hair was extremely excellent in the hair opening durability (the hair opening was small) as compared with the PBT hair and the nylon hair.

  Thus, the toothbrush using the PTT bristles is excellent in the opening durability of the bristles as a toothbrush because of the excellent property of bending recovery of the PTT bristles. In fact, when a toothbrush using PTT bristles is continuously used, it can be realized that the opening durability of the bristles is very excellent as compared with conventionally used nylon bristles and PBT bristles. However, if used over a long period of time, depending on the brushing method and how to apply the force at the time of brushing, even if the opening of the hair is not recognized, the tip of the hair wears down and the cleaning function as a toothbrush decreases. Also comes out. In that case, if only the opening of the hair is used as a guideline for the replacement timing of the toothbrush, the toothbrush whose cleaning function has deteriorated will continue to be used forever, and the oral cleaning as expected by the user is sufficient. It becomes impossible to do.

  Moreover, since the PTT hair is very excellent in the opening durability of the hair, there are cases where it is used more times (for example, twice or more) than conventional nylon hair and PBT hair. As a result, force continues to be applied repeatedly to the brush, and some of the brush may be torn or broken even though the tip is not so open.

  On the other hand, as a technique for displaying the replacement timing due to wear of the hair ends, Patent Document 4 (Japanese Utility Model Laid-Open No. 56-92518), Patent Document 5 (Japanese Utility Model Laid-Open No. 59-77430), and No. 152406, JP-A-6-277118, and the like, but were supposed to be pork which is a natural material as a material, and nylon which has been mainly used as a toothbrush brush as a synthetic material. In addition, the polyester material is partially mentioned in these publications, and although the type is not particularly limited, it has practically good physical properties for a toothbrush and is industrially available at the time of filing. PBT resin or polyethylene terephthalate (PET) resin was assumed.

  Synthetic fibers such as nylon and PBT are softer than teeth, so if they are used repeatedly continuously, they will be scraped off by the abrasive in the dentifrice, but on the other hand, the force of repeated bending during brushing is added. The bristles gradually bend and open to the outside. The prior art is a technique that combines these bending characteristics and color changes due to wear of the hair tips.

  Nylon hair, PBT hair, and even PET hair have different physical and chemical properties such as the influence of the ingredients in tooth and dentifrice (especially abrasives) depending on the characteristics of each material. However, the opening characteristics of the hair after repeated brushing did not show a clear difference between nylon and actual use.

  On the other hand, PTT hair which is extremely excellent in the opening durability of the hair has not been sufficiently studied, and the hair itself actually wears and deteriorates despite the fact that the hair does not open (bend), and accordingly the hair In some cases, the cleaning ability could not be maintained, such as lowering the waist strength.

  In recent years, since the PTT hair has become a level of practical use as a toothbrush hair in terms of quality and cost, the present inventors have examined the above problems, and as a result, display deterioration of the toothbrush function for the PTT hair. Developed technology.

  The present invention provides a toothbrush that uses a PTT bristle and can visually indicate the state of deterioration of the brush before it is torn or broken by repeated use, regardless of the open state of the tip. It is intended to do.

  In order to achieve the above object, the invention of claim 1 is a toothbrush using PTT bristle for a part or all of the brush planted on the head planting surface, and the cross-section of at least a part of the PTT bristle is colored. Alternatively, areas with different color intensities are formed, and the color or color density of the brush surface changes due to wear due to repeated use, or the area of the color or color intensity on the brush surface changes. It is what you do.

  According to a second aspect of the present invention, in the toothbrush according to the first aspect, when viewed in a cross section perpendicular to the long axis of the brush, the boundary where the color or the color intensity changes is 1-7 of the brush radius from the brush surface. It is characterized by a depth of 5%.

  According to a third aspect of the present invention, in the toothbrush according to the first or second aspect, the regions having different colors or color densities are present within at least 3 mm from the tip of the brush.

  According to the invention of claim 1, since the PTT hair is used as the brush to be implanted, it has excellent durability against the opening of the toothbrush tip, and the high cleaning effect by brushing the tip of the conventional nylon hair or PBT hair Can be maintained over a long period of time, and the PTT hair has regions with different colors or color densities, and the color or color density of the brush surface changes due to wear due to repeated use, or the brush Since the area of the part with different color or color density on the surface is changed, it is possible to visually display the deterioration of the cleaning function due to the deterioration of the brush itself without depending on the openness of the hair tip. The user can easily be notified of the replacement timing of the toothbrush.

  According to the invention of claim 2, since the boundary portion where the color or the color density changes is set to a depth of 1 to 7.5% of the brush radius from the brush surface, the toothbrush is replaced before the brush breakage or the like occurs. Can tell the time.

  According to the invention of claim 3, since the regions having different colors or color densities are located within 3 mm from the tip of the brush where the brush is most likely to be worn, the replacement time of the toothbrush is more reliable and sensitive. I can inform you.

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, the example of the PTT hair of the core sheath structure used with the toothbrush of this invention is shown.
FIG. 1A shows an example of a PTT hair 10 having a double core sheath structure in which a core portion 11 and a sheath portion 12 having different colors or color densities are arranged concentrically, and FIG. 1B shows a color or dark color. An example of the PTT hair 10 having a triple core sheath structure in which the core portion 11, the first sheath portion 12, and the second sheath portion 13 of different thicknesses are arranged concentrically, FIG. An example of a PTT hair 10 having a double core sheath structure in which different core portions 11 and sheath portions 12 are eccentric, FIG. 1 (d) shows the core portion 11 by further increasing the eccentricity in the PTT hair of FIG. 1 (c). Examples of the PTT hair 10 having a double core sheath structure in which a part of the PTT hair 10 is exposed are shown.

  In the case of a double core sheath structure as shown in FIGS. 1A, 1C, and 1D, by changing the color of the core portion 11 and the sheath portion 12 or the intensity of the color, the wear is reduced to the core portion 11. When it is reached, the color or intensity of the color will change, indicating that it is time to replace the toothbrush. In the case of this double-core sheath structure, it is preferable that the outer sheath portion 12 is colored or the color of the outer sheath portion 12 is darkened because the contrast of the wear change is easily obtained.

  Moreover, when it is set as the triple core sheath structure like FIG.1 (b), about any 1 or 2 or all of the core part 11, the 1st sheath part 12, and the 2nd sheath part 13, the color or By changing the color intensity, it is possible to inform when the toothbrush is to be replaced. For example, if the color or color intensity of all of the core part 11, the first sheath part 12, and the second sheath part 13 is changed, the first color or the color when the wear reaches the first sheath part 12 is changed. A change in the color intensity appears, so that a notice is given that the time for replacement is approaching, and when the wear reaches the core 11, the color or color intensity changes again. You can be informed that a reasonable replacement time has been reached. The outermost second sheath portion 13 is a transparent layer, and the outermost transparent second layer 13 is changed by changing the color or color density of the inner core portion 11 and the first sheath portion 12. The sheath portion 13 can act as a protective layer for the brush, and the wear can be displayed by the inner core portion 11 and the first sheath portion 12. In the case of this triple-core sheath structure, it is preferable to color the portion of the first sheath 12 sandwiched therebetween or to darken the color because the contrast of the change in wear is easily obtained.

  In order to make the PTT hair 10 having the above structure, for example, a colorant may be added to the resin of the target layer and the color or color density may be changed during spinning by coextrusion. In order to prepare after processing, for example, a laser coloring dye is previously contained in the resin, and after spinning by the above co-extrusion, the laser coloring dye is partially irradiated with laser light to obtain a color or color of a specific region. You can change the density.

In FIG. 2, the example of the PTT bristle of the sea island structure used with the toothbrush of this invention is shown.
FIG. 2A shows an example of the PTT hair 20 having a sea-island structure in which an island 22 having a substantially elliptical cross section is formed inscribed in the outer edge of the sea 21 in the sea 21 having a circular cross-section. ) Is an example of a PTT hair 20 having a sea-island structure in which four island portions 22 are arranged at equal intervals, and (c) is a PTT hair having a sea-island structure in which two island portions 22 are slightly projected from the outer peripheral surface of the sea portion 21. Examples of hairs 20 are shown. In the case of the PTT hair 20 having the sea-island structure, it is generally preferable to color the island portion 22 or to darken the color because the wear change contrast is easily obtained. The PTT hair 20 having the sea-island structure can also be made in the same manner as the PTT hair 10 having the core-sheath structure described above.

  As will be apparent from the examples described later, in the PTT hairs 10 and 20 shown in FIG. 1 and FIG. 2, the sheath portions 12 and 13 or island portions serving as boundary portions where the color or color intensity changes. The depth d of 22 is 1 to 7.5% of the brush radius from the brush surface, preferably 1 to 5% when viewed in a cross section perpendicular to the long axis of the brush. . If it is set within this range, it is possible to notify the time for replacement of the toothbrush before the brush easily breaks due to wear.

  Moreover, in the above example, an example in which the PTT hair provided with regions having different colors or color depths is realized by the core-sheath structure or the sea-island structure, but is not limited to this structure. It can also be obtained by spinning a brush having a single structure made of PTT resin and dyeing it from the outer surface of the brush to a predetermined depth d.

  FIG. 3 shows an example of a toothbrush according to the present invention produced using the PTT bristles 10 and 20 shown in FIG. In the drawing, the blacked out portions are regions having different colors or color densities.

  FIG. 3A shows that the PTT hair 10 (20) is used for all the brushes implanted in the toothbrush head portion 31, and each PTT hair has a color or a dark color over the entire length from the proximal end portion to the distal end portion. It is an example when the area | region from which length differs is provided. In this case, all the brushes in one hair bundle may be composed of the PTT hairs 10 (20) having areas with different colors or color densities, or have areas with different colors or color densities. Normal PTT hair that is not present may be mixed.

  FIGS. 3B to 3D show an example in which the PTT hair 10 (20) is used only for some of the hair bundles planted in the toothbrush head portion 31. FIG. is there. Thus, when giving a wear display function only to some hair bundles, the place which uses PTT hair 10 (20) is the front-end | tip part (FIG.3 (b)), rear-end part (FIG.3) of a head part, for example. (C)), side portions (FIG. 3 (d)), center portion, and the like are determined according to the specifications of the toothbrush, but usually, the tip portion, the side portions, the rear end portion, etc. are desirable because the wear display is easy to see. The hair bundle using the PTT hair 10 (20) is not limited to one bundle, and may be a plurality of bundles, for example, in units of columns or rows.

  FIG. 4 shows still another example of the toothbrush according to the present invention produced using the PTT bristles 10 and 20 shown in FIG. FIG. 4A shows a case where the PTT hair 10 (20) is used for three hair bundles on the tip side, and a region having a different color or color density is given only to the tip portion of the hair tip (the blacked-out portion). FIG. 4B shows an example in which a region having a different color or color density is provided at a position slightly below the tip of the hair tip, and FIG. 4C shows the color or color density in each hair bundle. Each example shows a case where different regions are changed step by step.

  The position of the PTT bristle where the color or the color intensity is different is determined according to the specification of the toothbrush, but as shown in FIG. 4, at least the tip of the brush tip It is desirable to be included within 3 mm.

  That is, in the past, a brushing method such as a roll method using a brush belly has been the mainstream as a toothbrushing method, but in recent years it is lighter using a hair tip according to the situation of each tooth. Brushing the hair with the force of brushing has become the mainstream. For this reason, it is preferable to set so that there is a region having a different color or color density within 3 mm from the bristle end portion, preferably at least 3 mm from the bristle tip.

  As described above, the depth d of the boundary where the color or color density changes due to wear is 1 to 7.5% of the brush radius from the brush surface when viewed in a cross section perpendicular to the brush long axis. Depth, preferably 1-5%, but considering the toothbrush specifications and the effect on brush wear due to the flocking position, set it to an appropriate depth d within the above range. It is preferable to adjust the display sensitivity according to the purpose.

  For example, in the case of a toothbrush with a large flocked portion, the burden on individual brushes due to one brushing is small, wear of the hair tip is less likely to occur, and a small flocked portion has the opposite tendency. In addition, “toe polishing” and “heel polishing” may be performed. In that case, the toe part (front end part) and the heel part (rear end part) of the tip of the hair tip are within the same toothbrush flocking part. Wear tends to occur.

  The PTT hair used in the present invention can be used for a toothbrush in the form and combination as described below, and may be used for all brushes implanted in the toothbrush head portion, or a part of the hair bundle (for example, flocking) The outer peripheral part, the front end side, the central part or the rear end side of the part) or a part of the brushes in the hair bundle. It only has to be able to recognize the change.

  As the main material of the brush, a PTT resin is used, and a material having characteristics described in, for example, Patent Document 1 and Patent Document 3 is used. In particular, the one having a hot water shrinkage (JIS L 1013: 1999) of 0 to 0.4%, more preferably 0 to 0.3% may be used.

  When the cross section of the brush has a core-sheath structure as shown in FIG. 1 or a sea-island structure as shown in FIG. 2, not only PTT resin but also commonly used polyamide resins (eg, nylon 6-12, nylon 6-6) 10 and 12 nylon, etc.), polyester resin (eg, polybutylene terephthalate, polyethylene terephthalate, etc.), hard resin such as polypropylene resin, or a composite filament combined with soft resin such as thermoplastic elastomer, but durability of PTT resin In order to make use of the properties, it is preferable that all layers or all sea portions and island portions are made of PTT resin, and the coloring of each portion is selected according to the toothbrush specifications.

  As for the coloring of the resin that constitutes the brush, it can be used as it is (transparent), transparent pigmented or dyed pigments, or opaque colored (including white) brushes, etc. It is appropriately selected in consideration of the degree of change, the merchandise of the appearance of the toothbrush, and the like. Further, if necessary, two or more of them may be used in combination in units of hair bundles or in units of brushes in the hair bundle.

  As described above, as described above, the resin itself is colored when the brush (filament) is spun, or the laser coloring dye is added and laser irradiation is performed after spinning, or after spinning or accompanying the spinning process. Can be colored from the brush surface. In addition, the state of a cut piece (hair bundle having a brush length of about 25 to 35 mm) before flocking to the toothbrush head portion, or after flocking to the head portion, only the tip portion of the brush or the entire brush can be colored. .

  It can also be modified within a range that does not significantly impair the characteristics of the brush, and contains heat and light stabilizers, flame retardants, fillers, surface lubricants, antistatic agents, bactericidal materials (antibacterial materials), etc. Furthermore, other hard resins and elastomers may be appropriately blended or applied.

  For spinning, whether it is a single structure or a composite structure such as a core-sheath structure or a sea-island structure, a commonly used spinning method may be used, and the used brush resin is melted or used as a solvent. It melts into a fluidized state, and this is extruded from the spinneret pores prepared to have the desired cross-sectional configuration into a gas or liquid, cooled and solidified, made into an unstretched brush, and then steamed in a hot water bath. A method in which the film is stretched or relaxed in a bath and then wound around a desired bobbin or the like is suitable. If necessary, surface treatment can be performed with a finishing agent such as an antistatic agent or a lubricant in the process.

  Furthermore, the brush after spinning is bundled by a predetermined number depending on the manufacturing method of the toothbrush and wound into a spool, or is cut to a certain length through a normal spinning process, and is linearly several cm to 10 cm. In order to further reduce the residual strain of the brush after being bundled to a certain diameter and wound with paper or film, offline heat treatment can be performed at 60 ° C. to 160 ° C. for several minutes to several days, for example.

  As the PTT hair used in the toothbrush of the present invention, the concentric double-core sheath structure (see FIG. 1 (a)) spun by coextrusion is easy to control the thickness of the sheath portion 12, and the color Changes are also easy to clarify, which is preferable. Moreover, as a combination of coloring, the sheath 12 can be colored, and the core 11 can be natural (non-colored), white or other colored, or vice versa. Considering the magnitude of the color change, the sheath 12 is preferably colored in a dark color such as blue, or a color with strong hiding power, and the core 11 is colored in a natural, white, or light color. It is preferable that the contrast of the change is obtained.

  The brush thickness is 3 to 12 mil (0.08 to 0.31 mm), preferably 5 to 11 mil (0.13 to 0.28 mm) from the viewpoint of usability, cleaning function and durability. Usually, the diameter is the same in one brush except for the rounded ends, but it may be twisted at a certain pitch toward the long axis of the brush, or wave processing or crimp processing may be added. In the vicinity of the root portion of the hair bundle, it may be in the form of tapered hair (for example, the diameter of the tip portion is 0.01 to 0.08 mm) whose diameter gradually decreases toward the brush tip with the above-mentioned brush thickness. Further, the tip shape of the brush portion may be processed into a spatula shape, a scraper shape, a spherical shape, or the like. In this way, when the cross-sectional diameter of the hair tip is changed, the formation of the color or the region having a different color density may be performed by a coloring process after the shape processing.

  The cross-sectional shape of the brush is usually circular as shown in FIG. 1 and FIG. 2, but it includes an ellipse, a triangle, a quadrangle, a pentagon, a hexagon, and the like with non-uniform side lengths. Various polygons, and shapes that are partially uneven, such as star shapes, three-leaf and four-leaf clover shapes, may be straight lines, curves, or indefinite shapes that combine straight lines and curves. An arbitrary shape is selected according to the shape, but a circular cross section is most preferable in terms of physical strength.

  The cross-sectional shape of the hair bundle is usually circular, but it is not necessarily circular, and may be an indeterminate shape combining polygons such as triangles and squares and straight lines and / or curves according to the design of the flocked portion. Good. In particular, in the case of flat line flocking, these bundles of irregular shapes and thin wall hole flocking can be combined to form a linear or curved apparently continuous hair bundle group.

  The bristles bundled with the brushes do not have to be made of the same brush diameter or color. For example, 6 mil (0.152 mm) and 7 mil (0.178 mm) or 6 mil and 8 mil (0. 203 mm) hair can be combined as appropriate in consideration of appearance, usability, cleaning feeling, cleaning effect and the like. Further, different brush materials may be combined, or may be combined with a rubber-like brush or chip such as silicon or elastomer.

  The thickness of the bundle of hair bundles (or the diameter of the flocked hole) is generally a circle with a diameter of 1 mm to 2.5 mm, but the flock of one brush unit or a diameter smaller than 1 mm, or 2 A hair bundle having a diameter exceeding 5 mm or a hole diameter is also used, and in a general arrangement, the distance between hair bundle roots (or between holes) is between 0.3 mm to 1.5 mm between hair bundles (between holes). Arranged at a distance.

  In the case of a hair bundle having a circular cross section, the hair bundle is usually arranged in a lattice shape or a zigzag shape, and 2 to 6 rows in the handle width direction (3 to 3 as the maximum width of the flocked portion on the head flocked surface). About 13 mm), and 4 to 12 rows (about 5 to 35 mm as the maximum length of the flocked portion on the head flocking surface) are arranged in the handle length direction, but a combination of the hair bundle cross-sectional shape, size and arrangement Can be appropriately selected according to the intended cleaning function.

  As a method for flocking a brush or a bunch of hair to a flocking surface of the head part, a conventional method can be used. For example, a bunch of hair using a flat wire (a retaining member such as brass, stainless steel, resin, biodegradable resin). A flat wire type flocking method in which the hair is folded in two, an in-mold type flocking method in which one end of the hair bundle is bonded by means of heat or the like, and the head portion resin is filled and fixed in a state where the bonded portion is in the mold ( For example, see Japanese Patent Application Laid-Open No. 61-268208 and Japanese Patent Publication No. 9-512724, and a heat fusion type flocking method in which one end of the hair bundle and the head portion are melt-bonded by means of heat or the like (for example, No. 60-241404) can be used.

  When fixing the hair bundle or brush to the toothbrush head part, the packing factor should be 60 to 100% for good hair standing, excellent appearance and excellent hair opening durability, and efficient hair tip Since it can be used, it can be set as a toothbrush with a high cleaning effect. Furthermore, in the case where the toothbrush head is a toothbrush made of a soft resin such as a thermoplastic soft resin or a silicone resin, a good toothbrush similar to the above should be obtained if the packing factor is 60 to 120%. Can do.

  Here, the packing factor is a value obtained by dividing the sum of the cross-sectional areas of one to a plurality of brushes fixed to the flocked hole by the flocked hole cross-sectional area in the case of the flat-wire type flocking method and the heat fusion type flocking method. Is multiplied by 100 and expressed in%. However, in the case of the flat wire type flocking method, the cross-sectional area of the flocked hole is a value excluding the area viewed from above the flocked hole of the flat line existing in the flocked hole. Also, in the case of in-mold type flocking method, and when the flocked hole is not formed in the head part in advance by the heat fusion type flocking method, instead of the flocked hole cross-sectional area, the hair bundle is fixed when fixing to the head part. Alternatively, the hole cross-sectional area of the jig for holding the brush is used as the flocked hole cross-sectional area and divided.

  The angle of the hair bundle or brush to be planted does not necessarily have to be perpendicular to the head surface of the head part, for example, the head part flocking in which the hair bundle is implanted for the purpose of enhancing the scraping effect in a specific direction. In some cases, the hair is implanted with an inclination of about 15 to 20 degrees with respect to the surface.

  As for the hair cutting shape of the flocked portion, generally flat cutting with a uniform plane, mountain cutting with a top, step cutting with changing the brush length (hair length) stepwise, and the like are appropriately selected. This hair cutting portion can be the entire flocked surface, a unit of hair bundle, or a combination of various shapes by means of a cutter shape or a plurality of hair cutting steps. Usually, the tip of each brush has its tip rounded. When the hair cutting process is not performed as in the case of tapered hair, the tip rounding process can be omitted.

  The brush length (hair length from the head flocked surface) is appropriately selected in consideration of the feeling of use and the cleaning effect, but is generally 8 to 12 mm for adults and 6 to 10 mm for children. .

  The material of the toothbrush handle including the head portion is preferably a thermoplastic resin having a flexural modulus of 500 to 3000 MPa (JIS K7203), polyolefin (polypropylene, polyethylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, etc.). , Polycarbonate (including blends with polyester), polyarylate (including blends with polyester), polyoxymethylene resin, AS resin, ABS resin, cellulose propionate, polyamide, polyurethane, PMMA resin, etc. However, polypropylene is preferable from the viewpoint of price and workability.

  Moreover, it can also be set as a multicolor molded handle by combining these resins, thermoplastic elastomers (olefin type, styrene type, urethane type, nylon type, etc.), and silicon resin. Furthermore, by constituting with two or more kinds of materials having different elastic moduli, part or all of the toothbrush handle including the head portion can be made flexible. In addition, when importance is attached to transparency, for example, PCTA resin, which is a kind of polyester manufactured by Eastman, USA, is preferable from the viewpoint of cost and dentifrice resistance.

  The thickness of the toothbrush head part is 2 to 5 mm as the thickness of the tip part, and the width is about 0.5 to 1.3 mm as the edge width of the head part to the width of the hair bundle or brushed part. It is the width added to.

Below, the result of the use test of the toothbrush using PTT hair is shown.
Toothbrush using PTT bristles with a diameter of 0.204 mm and 23 flocking holes with a diameter of 1.6 mm (2 tips + 3 holes × 7 rows, vertical hole pitch: 2.6 mm, horizontal hole pitch; 2.3 mm) A hair bundle of an average of 19 brushes on the head is folded in half with a brass flat wire and planted, and the brush length (hair length from the head planting surface) is cut into 9.0 mm, then the brush The bristles were rounded to prepare a toothbrush using PTT bristles. This was used by 20 panelists in the usual manner until they reached the state of a toothbrush that they thought was the time for replacement.

  Appearance observation of the brush roots of the collected toothbrush and the hair tips of each PTT hair at a position 3 mm below the tip of the hair bundle at each of the tip, center and rear ends of the head flocking surface The brush diameter was measured with a thickness gauge. Table 2 shows the result of rearranging the measurement results in the order in which the diameters of the brush tips were reduced.

  Similarly, the results obtained using PTT hair having a diameter of 0.152 mm are shown in Table 3.

  As is apparent from the results of Tables 2 and 3, the brush roots are broken when the brush tip diameter is reduced from 7.5% to 5%. Therefore, in PTT hair, if it is possible to display a change in the tip state with a thickness within 7.5%, more preferably within 5% of the tip brush diameter, physical deterioration such as a broken root of the brush occurs. It was found that the toothbrush replacement time can be displayed before doing this.

  On the other hand, if the sensitivity is too high so that the change in the tip state is displayed while the brush is still worn slightly, the indication of toothbrush replacement will appear before the brush is still degraded, so at least use It is desirable to set so as to display a change in the state of the hair tip after it becomes thinner by 1% or more than the previous brush diameter.

  From the above results, in the toothbrush of the present invention, when the depth d (see FIGS. 1 and 2) of the boundary portion where the color or the color density changes is viewed in a cross section perpendicular to the brush long axis. The depth from the brush surface is 1 to 7.5% of the brush radius, more preferably 1 to 5% of the brush radius.

The example of the PTT hair used with the toothbrush of this invention is shown, (a) is an expanded sectional view of the PTT hair of a double core sheath structure, (b) is an expanded sectional view of the PTT hair of a triple core sheath structure, (c) ) Is an enlarged cross-sectional view of the eccentric PTT hair having a double core sheath structure, and (d) is an enlarged cross sectional view of the PTT hair having a double core sheath structure in which a part of the core portion is exposed. The other example of the PTT hair used with the toothbrush of this invention is shown, (a) is an expanded sectional view of the PTT hair of the sea island structure which has one island part which contact | connected the outer periphery of the sea part, (b) is an island part. 4 is an enlarged cross-sectional view of PTT hair having a sea-island structure in which four are arranged at equal intervals, and FIG. 5C is an enlarged cross-sectional view of PTT hair having a sea-island structure in which island portions are projected from the outer peripheral surface of the sea portion. FIG. 3 shows an embodiment of a toothbrush according to the present invention produced using the PTT bristles of FIG. 1 or FIG. 2, wherein (a) is a schematic side view of a toothbrush having a wear display function over the entire length of the brush; ) Is a schematic side view of a toothbrush in which only the hair bundle on the front end side of the head portion is provided with a wear display function, and (c) is a schematic view of a toothbrush in which only the hair bundle on the rear end side of the head portion is provided with a wear display function. Side view (d) is a schematic side view of a toothbrush having a wear display function only on the hair bundle near the center of the head portion. FIG. 3 shows another embodiment of the toothbrush according to the present invention produced using the PTT bristles of FIG. 1 or FIG. 2, wherein (a) is a schematic side view of a toothbrush provided with a wear display display function at the tip of the bristles. FIG. 4B is a schematic side view of a toothbrush provided with a wear display function at a position slightly below the tip of the bristles, and FIG. 5C is a schematic side view of the toothbrush in which the position of the wear display function portion is changed stepwise. It is.

Explanation of symbols

10 PTT hair having a core-sheath structure 11 Core part 12 Sheath part (first sheath part)
13 Second sheath portion 20 PTT hair having sea island structure 21 Sea portion 22 Island portion 31 Toothbrush head portion 32 Normal brush

Claims (3)

  A toothbrush using PTT hair for part or all of the brush planted on the head surface, and forming a region having a different color or color intensity on a cross section of at least a part of the PTT hair. A toothbrush characterized in that the color or color density of the brush surface changes due to repeated wear, or the area of the portion of the color or color density that occupies the brush surface changes.   The boundary where the color or the color intensity changes when viewed in a cross section perpendicular to the brush long axis is at a depth of 1 to 7.5% of the brush radius from the brush surface. The toothbrush according to 1. The toothbrush according to claim 1 or 2, wherein the regions having different colors or color densities are present at least within 3 mm from the tip of the brush.

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