KR102319783B1 - Toothbrush - Google Patents

Abstract

Prevents hair breakage and hair splitting when the toothbrush is used repeatedly over a long period of time. The toothbrush 1 has a handle body 10 and a head portion 20 extending from the tip of the handle body 10, and a plurality of bristles 21 of a plurality of bristles 21a are implanted in the head portion 20, , all or part of the bristles 21a are made of polybutylene terephthalate filaments, and the filaments have a zero shear viscosity at 240° C. in the range of 200 to 300 Pa·s, and elongation at break per unit area. is less than 2600%.

Description

toothbrush {TOOTHBRUSH}

The present invention relates to toothbrushes.

This application claims priority based on Japanese Patent Application No. 2013-262893 for which it applied to Japan on December 19, 2013, The content is used here.

For the prevention of periodontal disease, it is important to remove the jig from the cervical region. Therefore, in order to improve the cleaning property of the cervical part by a toothbrush, especially a periodontal pocket, what made the so-called tapered bristles with sharpened bristles as bristle, or the thing using fine bristles may be used as a toothbrush (patent document 1).

Japanese Patent No. 3145213

By the way, when a toothbrush was used repeatedly over a long period of time, the bristle|brush that the bristles are said to be bent in the vicinity of a hair-transplantation surface may generate|occur|produce. In particular, this problem was remarkable when polyester-type resin was used as a raw material of bristles. Moreover, the uprightness of bristle|bristle fell and it may generate|occur|produce that the area|region surrounded by the outermost all bristles spreads compared with the time of non-use in planar view.

Then, this invention makes it a subject to prevent the hair breakage at the time of repeatedly using a toothbrush over a long term, and hair spreading.

The toothbrush according to the embodiment of the present invention has a handle body and a head portion extending from the tip of the handle body, and in the toothbrush having a plurality of bristles in the head portion, all or part of the plurality of bristles is a filament containing polybutylene terephthalate as a constituent material, the filament having a zero shear viscosity at 240°C in the range of 200 to 300 Pa·s, and the elongation at break per unit area obtained by the following formula (1) is less than 2600%.

Elongation at break per unit area (%) = Elongation at break (%) / cross-sectional area (mm2) (1)

In addition, the elongation at break is a value measured using a tensile tester under measurement conditions of a measurement temperature of 25° C. and a tensile rate of 20 mm/min. The cross-sectional area is the cross-sectional area of the thickest part to be described later.

In addition, the toothbrush according to another embodiment of the present invention has a zero shear viscosity at 240° C. of the filament in the range of 260 to 280 Pa·s.

In addition, the toothbrush according to another embodiment of the present invention has an elongation at break of 2500% or less per unit area measured under the measurement conditions of a measurement temperature of 25° C. and a tensile rate of 20 mm/min using the tensile tester of the filament.

In addition, in the toothbrush according to another embodiment of the present invention, the bristles have a substantially circular cross-section, and a thickness of 4 to 10 mils.

(Effects of the Invention)

The toothbrush of the present invention can prevent hair breakage and hair splitting when the toothbrush is repeatedly used over a long period of time.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows one Embodiment of the toothbrush of this invention.
It is a schematic diagram explaining the tensile test in an Example and a comparative example.

One Embodiment of the toothbrush of this invention is described.

The side view of the toothbrush of this embodiment in FIG. 1 is shown. The toothbrush 1 of this embodiment is a handle body 10 and the head part 20 extended to the handle body 10 are integrally molded, and the some bristles 21a are bundled in the head part 20. A plurality of hair bundles 21 are implanted.

The head portion 20 has a length in the handle axis direction of the handle body 10, and has a substantially rectangular flat plate shape in which the corners are corner cut by a curve in plan view, and one side 20a [ A plurality of hair-transplantation holes are formed in the hair-transplantation|transplantation surface 20a]. The hair-transplantation|flocking part which the hair|bristle bundle 21 is implanted in this hair-transplantation hole, and consists of the some hair|bristle bundle 21 is formed.

The size of the head part 20 can be appropriately selected with reference to the size of the head part of a conventional toothbrush, and can be determined in consideration of operability in the oral cavity, and the like.

When the magnitude|size of the width direction of the head part 20 is too long, operability in an oral cavity will fall, and when it is too short, the number of hair|bristle bundles implanted will decrease too much, and a cleaning effect will be easy to be impaired. Therefore, the magnitude|size of the width direction of the head part 20 becomes 5-13 mm, for example. In addition, let the width|variety of a head part here be the width|variety of the part with the largest width|variety. For example, in the case where the width near the tip of the head is made small due to a round structure or the like, it is the width of the portion excluding the portion.

Although the operability in the oral cavity can be improved so that the size of the thickness direction of the head part 20 is thin, the intensity|strength of the head part 20 tends to become inadequate when it is too thin. Therefore, the thickness of the head part 20 can take into consideration the material of the handle body 10, etc., and can be determined, for example, 1.5-5 mm is preferable and 2-3 mm is more preferable. In addition, let the thickness of a head part here be the thickness of the part with the largest thickness. For example, when the thickness is made small due to a round structure or the like around the edge of the head, it is the thickness of the portion excluding the portion.

When the magnitude|size of the longitudinal direction of the head part 20 is too long, operability in an oral cavity is easy to be impaired, and when it is too short, the number of the hair|bristle bundle 21 implanted becomes too small, and a cleaning effect is easy to be impaired. Therefore, the magnitude|size of the longitudinal direction of the head part 20 is suitably determined in the range of 10-26 mm.

The shape of a tuft hole is not specifically limited, Circles, such as a perfect circle or an ellipse, polygons, such as a triangle and a quadrangle, etc. are mentioned.

The number of holes of a tuft hole is not specifically limited, For example, it is set as 10-60 holes.

The diameter of a hair-transplantation hole is determined by the thickness of the hair|bristle bundle 21 requested|required, and is set to 1-3 mm, for example.

The arrangement pattern of the tuft holes is not particularly limited, and any arrangement pattern such as a so-called checkerboard shape or a zigzag shape (also called a staggered shape) may be used.

All or one part of the some bristles 21a in this embodiment is a filament which uses polybutylene terephthalate (PBT) as a structural material. The fact that the bristles 21a are filaments made of polybutylene terephthalate as a constituent material indicates that a fine wire made of polybutylene terephthalate as a constituent material is used as it is as bristles. Here, using polybutylene terephthalate as a constituent material means a structure in which the constituent material of the filament is substantially composed of polybutylene terephthalate excluding impurities, and specifically, 90 to 100% by weight of polybutylene terephthalate It is preferable that it is lenterephthalate. When the resin constituting the filament is polybutylene terephthalate, the tapered filament can be easily produced by manufacturing means such as chemical treatment.

Filament in which all or part of the plurality of bristles 21a is made of polybutylene terephthalate as a constituent material includes polybutylene terephthalate among the plurality of bristles 21a included in the bristles 21 as constituent materials. It is preferable that the filament is included in the number of 25% or more with respect to the total number of bristles 21a included in the hair bundle 21.

The shape of the bristle 21a may be the straight shape which is the same diameter over the whole longitudinal direction, and the taper shape tapered toward a bristle point may be sufficient as it. It is preferable that the bristle 21a is a tapered bristle (taper bristle) from a point which improves the cleaning property of a tooth neck part more.

When a part of the bristles 21a is a filament made of polybutylene terephthalate, the remaining bristles 21a are straight or tapered filaments made of a resin (for example, nylon) other than polybutylene terephthalate. can be used

The filament in the present embodiment has a zero shear viscosity at 240°C in the range of 200 to 300 Pa·s, and preferably in the range of 260 to 280 Pa·s. If the zero shear viscosity is less than the lower limit, hairs are easily broken. In addition, when the zero shear viscosity of the filament exceeds the upper limit, the moldability during extrusion molding to obtain the filament tends to decrease, and when the filament is tapered, the productivity tends to decrease.

The zero shear viscosity in this embodiment is calculated|required by the dynamic viscoelasticity measurement in 240 degreeC. Dynamic viscoelasticity measurement (or DMA) is a measurement in which a force varying with time is applied to a sample and a change in elastic modulus is obtained from a change in deformation of the sample caused thereby.

Specifically, by measuring dynamic viscoelasticity at 240° C., a graph is prepared in which the horizontal axis is the angular frequency (ω) and the vertical axis is the loss elastic modulus (G″), and from the graph, the loss elastic modulus at the angular frequency (ω) is 0. is calculated by the interpolation method, and the loss modulus when the angular frequency ω is 0 is taken as the zero shear viscosity.

In addition, for example, in the case of a filament containing polybutylene terephthalate as a constituent material, the zero shear viscosity is proportional to the 3.4th power of the weight average molecular weight of the polybutylene terephthalate molecule, so a compound contained as a constituent material of the filament is an index of the weight average molecular weight of That is, the greater the zero shear viscosity, the greater the weight average molecular weight of the compound.

Moreover, it is preferable that the breaking elongation per unit area of the filament in this embodiment is 2600 % or less, and it is 2500 % or less.

Here, the breaking elongation per unit area is a value represented by the following formula (1).

Elongation at break per unit area (%) = Elongation at break (%) / cross-sectional area (mm2) (1)

The cross-sectional area of a filament is, for example, a cross-sectional area in a cross-section (transverse cross-section) obtained by cutting the filament perpendicular to the longitudinal direction at the thickest position. The thickest position means, for example, that when the filament is tapered and the filament is thin (cross-sectional area) at both ends, the thin part at both ends is excluded. As an example, it is the average of the cross-sectional area of the site|part of the length 50-90% including the center in the longitudinal direction of a filament excluding the thin site|parts at both ends mentioned above. Further, the cross-sectional area may be estimated from the thickness at the time of manufacturing the filament (eg, estimated from the size of the mold of the molded device).

When the elongation at break per unit area of the filament exceeds the above upper limit, chamfering tends to occur. On the other hand, in consideration of the strength and thickness required as a filament generally used in toothbrushes, it is preferable that the elongation at break per unit area is 1500% or more. In consideration of these values, the elongation at break per unit area of the filament is preferably 1500 to 2600%, more preferably 1500 to 2500%.

In addition, breaking elongation is the value measured using the measurement conditions of 25 degreeC of measurement temperature, and 20 mm/min of tensile rate using a tensile tester. Here, the tensile tester can suitably use an instrument capable of applying a force to the sample in the tensile direction (eg, in the filament of the present embodiment, in the direction in which the filament is elongated with respect to the longitudinal direction). More specifically, an instrument capable of measuring the force when the sample is broken and the rate of change in length of the sample by applying a force in the tensile direction to the sample at a constant elongation rate may be used. As an example of a tensile tester, an autograph tester etc. can be used preferably.

Moreover, in this embodiment, it is preferable that 50% or more of the filaments which satisfy|fill the conditions of the said zero shear viscosity and break elongation per unit area are contained in the bristles 21a.

The elongation at break of the filament is affected by the spinning conditions during filament production. Therefore, in order to make the breaking elongation into the said range, what is necessary is just to adjust the elongation during a spinning process, and heat processing conditions suitably.

The cross-sectional shape of the bristles 21a cut perpendicular to the longitudinal direction at any position in the longitudinal direction is not particularly limited, and even if it is a circular shape such as a perfect circle or an ellipse, a polygon, a star shape, a three-leaf clover type, or a four-leaf clover type, etc. good.

The thickness of the bristles 21a can be determined in consideration of the material and the like, and when the cross section is circular, for example, 4 to 10 mil (1 mil = 1/1000 inch = 0.025 mm). Moreover, in consideration of a feeling of use, a feeling of cleaning, a cleaning effect, durability, etc., you may use combining the several bristles 21a from which thickness or the shape of a cross-section differs arbitrarily.

As a planting method of the said hair|bristle bundle 21, well-known methods, such as the method of inserting a flat wire, or the method of thermal welding, are applicable.

In the method of inserting a flat wire, a plurality of bristles 21a are bundled and folded in half, and a fixture called a flat wire is sandwiched therebetween, and the hair bundle 21 is implanted in each hair transplantation hole by driving it into the hair transplantation hole.

The flat line passes through the center of the tuft hole and is poured into the tuft hole so as to span the tuft hole. As a material of a flat wire, metals, such as brass and stainless steel, are mentioned, for example, In addition, hard plastic, biodegradable plastic, etc. are mentioned.

The length, width, and thickness of the flat line may be arbitrarily adjusted according to the hair bundle 21 or the tuft hole, but usually the length of the flat line is larger than the diameter of the tuft hole, and the width of the flat line is smaller than the depth of the tuft hole. Moreover, by adjusting the thickness of a flat line, the hair|bristle bundle 21 can be fixed reliably in a hair-transplantation hole, and a space|gap can be decreased. Moreover, it is preferable that the sum total of the length of the part protruding from both sides of a tuft hole is 0.3-0.6 mm in order to prevent a flat line from falling out from a tuft hole.

The material of the head part 20 and the handle body 10 can be determined in consideration of the rigidity and mechanical properties required for the head part 20 and the handle body 10, for example, bending elastic modulus (JIS K7203) 500 Resin of MPa or more (hereinafter, sometimes referred to as hard resin) is preferable, and resin of flexural modulus of 700 MPa or more is more preferable. Although the upper limit of the bending elastic modulus of resin used for the head part 20 and the handle body 10 is not specifically limited, For example, it is set as 3000 MPa. Specifically, for example, the bending elastic modulus of the material of the head part 20 and the handle body 10 is 500-3000 MPa, Preferably it can select from the range of 700-3000 MPa.

Examples of the resin having a flexural modulus of 500 MPa or more include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexylene dimethylene terephthalate (PCT), and polyacetal (POM). , polyethylene naphthalate (PEN), polystyrene (PS), acrylonitrile butadiene styrene resin (ABS), cellulose propionate (CP), polyarylate, polycarbonate or acrylonitrile styrene copolymer resin (AS) These etc. are mentioned, Especially, POM, PEN, PBT, PCT, etc. whose flexural modulus is 2000 MPa or more are preferable. By using resin with a bending elastic modulus of 2000 MPa or more, the head part 20 can be made thin, the operability in an oral cavity can be improved, and also the damage|damage of the handle body 10 can be prevented.

Further, the handle body 10 may be partially or entirely covered with a soft resin. Part or all of the handle body 10 is coated with the soft resin, so that the user's hand fit when the handle body 10 is gripped is improved, and the gripping finger can be prevented from slipping.

As soft resin, For example, Preferably resin of Shore hardness A90 or less, More preferably, resin of Shore hardness A30-80 is mentioned. As such a soft resin, elastomer resins, such as a polyolefin type elastomer, a styrene type elastomer, a polyester type elastomer, or a polyurethane type thermoplastic elastomer, or silicon, etc. are mentioned, for example.

As described above, the toothbrush of this embodiment has a zero shear viscosity at 240° C. in the range of 200 to 300 Pa·s, and a polybutylene terephthalate filament having a breaking elongation per unit area of 2600% or less. Therefore, hair breakage and hair splitting are prevented.

Example

(Example 1, Comparative Examples 1 and 2)

Polycyclohexylenedimethylene terephthalate resin (product name: Eastar BR203, flexural strength; 68 MPa, flexural modulus; 1900 MPa, Eastman Chemical Co., Ltd.) was injection molded to obtain an integrally molded product of the head part and the handle body. The diameter of the tuft holes was 1.5 mm, and the arrangement of the tuft holes was set to be 2 holes × 1 row, 3 holes × 1 row, 4 holes × 5 rows, and 3 holes × 1 row, respectively, from the tip of the head part toward the handle body.

Next, the bristle bundles of tapered bristles (7.5 mils) which consist of the filament made from polybutylene terephthalate shown in Table 1 were implanted in the head part by flat-wire hair transplantation, and the toothbrush was produced.

In addition, the zero shear viscosity of the filament and the elongation at break per unit area were measured as follows. Table 1 shows the measurement results.

[Zero Shear Viscosity]

Using a dynamic viscoelasticity measuring device (AR-2000ex manufactured by TA Instruments Co., Ltd.) equipped with a cone-disk (conical angle of 4°, cone diameter of 25 mm) as a jig of the measurement sample, the dynamic viscoelasticity was measured at 240° C. in frequency dependence mode. measured. This creates a graph in which the horizontal axis is the angular frequency (ω) and the vertical axis is the loss elastic modulus (G"), and from the graph, the loss elastic modulus when the angular frequency (ω) is 0 was calculated by interpolation. Angular frequency The loss elastic modulus when (ω) is 0 was made into zero shear viscosity.

[Elongation at break per unit area]

The elongation at break per unit area was obtained by performing a tensile test of the filament using an autograph manufactured by Shimadzu Corporation, and obtained by the following formula (1).

Elongation at break per unit area (%) = Elongation at break (%) / cross-sectional area (mm2) (1)

The conditions of the tensile test were a measurement temperature of 25°C, a tensile rate of 20 mm/min, and a distance between the chucks (fitting jigs for testing) of 5 mm. The plan view of the test piece used for the tensile test of this measurement is shown in a figure. Moreover, as shown in FIG. 2, the chuck|zipper was attached to the part except the part between (interval) of 2.5 mm of parts A and A from the midpoint C. As shown in FIG.

<Evaluation>

The toothbrush of each case WHEREIN: The hair|bristle bending durability and hair|bristle break durability were evaluated. An evaluation result is shown in Table 1.

[Bend durability]

The test solution in which a commercially available toothpaste was dispersed in water was set to 35° C., and the toothbrush was repeatedly cleaned reciprocally while pressing the hair bundle against the metal corrugated plate in the test solution. The test conditions at that time were a load of 300 g, a cleaning stroke of 40 mm, a reciprocating speed of 160 times/min, and a number of cleaning of 150,000 times. Then, the number of fractures per toothbrush after cleaning, ie, the number of hairs bent, was measured using a microscope. The column of "the number of hair breaks" of Table 1 shows the average value which measured the number of hair breaks with respect to 5 measured toothbrushes. The lower the number of bristle bends, the higher the bristle break durability.

[Buzzing Durability]

The width of the hair-transplantation part in the short axis direction of the toothbrush before and after cleaning was measured, the bristle spread width after cleaning was computed, and the ratio with respect to the hair-transplantation part width of an initial state was calculated|required. Based on the ratio, the following references|standards evaluated the hair opening.

◎: less than 20%

○: 20% or more - 60% or less

△: 60% or more -100% or less

×: greater than 100%

The toothbrush of Example 1 using tapered bristles made of PBT having a zero shear viscosity in the range of 200 to 300 Pa·s and having an elongation at break of 2600% or less per unit area did not easily cause breakage and splitting of hairs.

On the other hand, the toothbrush of the comparative example 1 using the tapered bristles made from PBT whose zero shear viscosity is less than 200 Pa*s was easy to generate|occur|produce hair breakage.

On the other hand, the toothbrush of the comparative example 2 using the tapered bristles made from PBT in which the breaking elongation per unit area exceeded 2600 % was easy to generate|occur|produce the bristle breakage.

1: toothbrush 10: handle body
20: head part 20a: hair transplantation surface
21: bristles 21a: bristles

Claims (4)

In the toothbrush having a handle body and a head extending to the tip of the handle body, the toothbrush having a plurality of bristles in the head portion is implanted with a plurality of bristles,
All or part of the bristles are made of polybutylene terephthalate filaments,
The filament has a zero shear viscosity at 240° C. in the range of 260 to 280 Pa·s, and the elongation at break per unit area measured using a tensile tester at a measurement temperature of 25° C. and a tensile rate of 20 mm/min. Toothbrush, characterized in that 1500% or more and 2500% or less. The method of claim 1,
The bristles have a circular cross-section and a toothbrush, characterized in that the thickness is 4-10mil. delete delete

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