WO2015093334A1

WO2015093334A1 - Toothbrush

Info

Publication number: WO2015093334A1
Application number: PCT/JP2014/082405
Authority: WO
Inventors: 浩子松尾
Original assignee: ライオン株式会社
Priority date: 2013-12-19
Filing date: 2014-12-08
Publication date: 2015-06-25
Also published as: KR102319783B1; CN105828666B; KR20160102149A; CN105828666A; JP2015116411A

Abstract

An objective of the present invention is to avoid bristle breakage or bristle wear when a toothbrush is used repeatedly over an extended period. Provided is a toothbrush (1) which comprises a handle body (10) and a head part (20) which extends from the leading end of the handle body (10), and in which a plurality of staples (21) of a plurality of bristles (21a) is embedded in the head part (20). All or part of the plurality of bristles (21a) are formed from a polybutylene terephthalate filament. The filament has a zero shear viscosity at 240°C in a range of 200-300Pa∙s, and a rupture elongation per unit area of 2600% or less.

Description

toothbrush

The present invention relates to a toothbrush.
This application claims priority based on Japanese Patent Application No. 2013-262893 filed in Japan on December 19, 2013, the contents of which are incorporated herein by reference.

For the prevention of periodontal disease, it is important to remove plaque from the cervical region. Therefore, in order to improve the cleaning performance of the tooth neck by the toothbrush, especially the periodontal pocket, a so-called tapered hair with a sharpened tip is used as a toothbrush, or a thin hair is used. There is a case where a thing is used (Patent Document 1).

Japanese Patent No. 3145213

However, when the toothbrush is repeatedly used over a long period of time, there is a case where the hair is broken near the flocked surface. This problem was particularly noticeable when a polyester resin was used as a raw material for hair. In addition, the uprightness of the hair is reduced, and when viewed in plan, the region surrounded by the outermost all hair may be spread more than when it is not used.
Then, this invention makes it a subject to prevent the breakage and the bristle-opening at the time of using a toothbrush repeatedly over a long term.

The toothbrush which concerns on the embodiment of this invention has a handle body and the head part extended at the front-end | tip of the said handle body, The toothbrush by which the bristles which have a plurality of hairs were planted by the said head part Wherein all or part of the plurality of hairs is a filament comprising polybutylene terephthalate, and the filament has a zero shear viscosity at 240 ° C. in the range of 200 to 300 Pa · s, and The breaking elongation per unit area obtained by the formula (1) is 2600% or less.
Breaking elongation per unit area (%) = breaking elongation (%) / cross-sectional area (mm ² ) (1)
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 speed of 20 mm / min. The cross-sectional area is the cross-sectional area of the thickest part described later.
In a toothbrush according to another embodiment of the present invention, the filament has a zero shear viscosity at 240 ° C. in the range of 260 to 280 Pa · s.
In addition, the toothbrush according to another embodiment of the present invention has a breaking elongation of 2500% or less per unit area measured using the filament tensile tester under measurement conditions of a measurement temperature of 25 ° C. and a tensile speed of 20 mm / min. is there.
In the toothbrush according to another embodiment of the present invention, the bristle has a substantially circular cross section and a thickness of 4 to 10 mils.

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

It is a side view which shows one Embodiment of the toothbrush of this invention. It is a schematic diagram explaining the tension test in an Example and a comparative example.

An embodiment of the toothbrush of the present invention will be described.
In FIG. 1, the side view of the toothbrush of this embodiment is shown. The toothbrush 1 of the present embodiment is formed by integrally forming a handle body 10 and a head portion 20 extending from the handle body 10, and a bunch of hair bundled with a plurality of hairs 21 a on the head portion 20. A plurality of 21 are planted.

The head portion 20 has a substantially rectangular flat plate shape in which the handle axis direction of the handle body 10 is long, and the corner portion is cut off with a curve in plan view, and a flocked hole is formed on one surface 20a (flocked surface 20a). Are formed. A hair bundle 21 is implanted in the flocked hole, and a flocked portion composed of a plurality of hair bundles 21 is formed.

The size of the head portion 20 can be appropriately selected with reference to the size of the head portion of a conventional toothbrush, and can be determined in consideration of the operability in the oral cavity.
If the size of the head portion 20 in the width direction is too long, the operability in the oral cavity is lowered, and if it is too short, the number of hair bundles to be implanted becomes too small, and the cleaning effect tends to be impaired. Therefore, the size of the head portion 20 in the width direction is set to, for example, 5 to 13 mm. Here, the width of the head portion is the width of the largest portion. For example, when the width of the vicinity of the tip of the head portion is reduced due to a round structure or the like, the width of the portion excluding that portion.
As the size of the head portion 20 in the thickness direction is thinner, the operability in the oral cavity is improved, but if it is too thin, the strength of the head portion 20 tends to be insufficient. Therefore, the thickness of the head portion 20 can be determined in consideration of the material of the handle body 10 and the like, and is preferably 1.5 to 5 mm, and more preferably 2 to 3 mm. Here, the thickness of the head portion is the thickness of the thickest portion. For example, when the thickness of the vicinity of the edge of the head portion is reduced due to a round structure or the like, it is the thickness of the portion excluding that portion.
If the size of the head portion 20 in the longitudinal direction is too long, the operability in the oral cavity is liable to be impaired, and if it is too short, the number of hair bundles 21 to be implanted becomes too small and the cleaning effect is liable to be impaired. Therefore, the size of the head portion 20 in the longitudinal direction is appropriately determined in the range of 10 to 26 mm.

The shape of the flocked hole is not particularly limited, and examples thereof include a circle such as a perfect circle or an ellipse, and a polygon such as a triangle or a rectangle.
The number of flock holes is not particularly limited, and is, for example, 10 to 60 holes.
The diameter of the flock hole is determined according to the desired thickness of the hair bundle 21 and is set to 1 to 3 mm, for example.
The arrangement pattern of the flock holes is not particularly limited, and may be any arrangement pattern such as a so-called grid pattern or staggered pattern (also called a staggered pattern).

All or part of the plurality of hairs 21a in the present embodiment is a filament made of polybutylene terephthalate (PBT). That the hair 21a is a filament having polybutylene terephthalate as a constituent material means that a thin wire having polybutylene terephthalate as a constituent material is used as the hair as it is. Here, 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 the like. Specifically, 90 to 100% by weight is polybutylene terephthalate. Preferably there is. When the resin constituting the filament is polybutylene terephthalate, a tapered filament can be easily produced by a manufacturing means such as chemical treatment.
That all or a part of the plurality of hairs 21a is a filament comprising polybutylene terephthalate as a constituent material, among the plurality of hairs 21a contained in the hair bundle 21, a filament containing polybutylene terephthalate as a constituent material, It is preferable that the number of hairs 21a included in the hair bundle 21 is 25% or more.
The shape of the bristles 21a may be a straight shape having the same diameter throughout the longitudinal direction, or may be a tapered shape that narrows toward the hair tips. The hair 21a is preferably a tapered hair (tapered hair) in terms of further improving the cleaning performance of the tooth neck.
When a part of the hair 21a is a filament made of polybutylene terephthalate, a straight or tapered filament made of a resin other than polybutylene terephthalate (for example, nylon) is used as the remaining hair 21a. Can do.

The filament in this 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. When the zero shear viscosity is less than the lower limit, the hair is easily broken. Further, if the zero shear viscosity of the filament exceeds the upper limit, the moldability during extrusion molding when obtaining the filament tends to be low, and the productivity tends to decrease when taper processing is performed. It is in.
The zero shear viscosity in the present embodiment is determined by dynamic viscoelasticity measurement at 240 ° C. The dynamic viscoelasticity measurement (or DMA) is a measurement for obtaining a change in elastic modulus from a change in strain of a sample caused by applying a force that changes with time to the sample.
Specifically, by measuring the dynamic viscoelasticity at 240 ° C., a graph in which the horizontal axis is the angular frequency ω and the vertical axis is the loss elastic modulus G ″ is generated, and the loss when the angular frequency ω is 0 is calculated from the graph. The elastic modulus is obtained by interpolation, and the loss elastic modulus when the angular frequency ω is 0 is defined as zero shear viscosity.
For example, in the case of a filament comprising polybutylene terephthalate as a constituent material, the zero shear viscosity is proportional to the power of the above-mentioned polybutylene terephthalate molecule, which is 3.4 powers of the weight average molecular weight. It is an index of molecular weight. That is, the greater the zero shear viscosity, the greater the weight average molecular weight of the compound.

Further, the filament according to this embodiment has a breaking elongation per unit area of 2600% or less, and preferably 2500% or less.
Here, the breaking elongation per unit area is a value represented by the following formula (1).
Breaking elongation per unit area (%) = breaking elongation (%) / cross-sectional area (mm ² ) (1)
The cross-sectional area of the filament is, for example, a cross-sectional area in a cross section (transverse cross section) obtained by cutting the filament perpendicularly to the length direction at the thickest position. The thickest position is the area in any cross section at that position, for example, when the filament is tapered and the filament is thin at both ends (the cross-sectional area is small), excluding thin parts at both ends. However, as an example, it is an average of the cross-sectional areas of the portions having a length of 50 to 90% including the center in the length direction of the filament, excluding the thin portions at both ends described above. Further, the cross-sectional area may be estimated from the thickness at the time of manufacturing the filament (for example, estimated from the size of the mold of the molded device).
When the elongation at break per unit area of the filament exceeds the upper limit, fleece breakage is likely to occur. On the other hand, in view of the strength and thickness required for filaments generally used in toothbrushes, the breaking elongation per unit area is preferably 1500% or more. In view of these values, the elongation at break per unit area of the filament is preferably 1500 to 2600%, more preferably 1500 to 2500%.
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 speed of 20 mm / min. Here, the tensile tester can appropriately use a device that can apply a force in the tensile direction (for example, in the filament of the present embodiment, the direction in which the filament is elongated in the length direction) to the sample. More specifically, an apparatus that can apply a force in the tensile direction to the sample at a constant elongation rate and measure the force at the time of the sample breaking and the sample length change rate can be used. As an example of the tensile tester, an autograph tester or the like can be preferably used.
In addition, in this embodiment, it is preferable that 50% or more of the filaments 21a satisfy the above-described conditions of zero shear viscosity and breaking elongation per unit area.

The breaking elongation of the filament is affected by the spinning conditions during filament production. Therefore, in order to make the breaking elongation within the above range, the stretching ratio and heat treatment conditions during the spinning process may be adjusted as appropriate.

The cross-sectional shape obtained by cutting the bristles 21a perpendicularly to the length direction at an arbitrary position in the length direction is not particularly limited, and may be a circle such as a true circle or an ellipse, a polygon, a star, or a trefoil. A clover shape or a four-leaf clover shape may be used.
The thickness of the hair 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). In addition, in consideration of a feeling of use, a feeling of cleaning, a cleaning effect, durability, and the like, a plurality of hairs 21a having different thicknesses or cross-sectional shapes may be used in any combination.

As a method of planting the hair bundle 21, a known method such as a method of driving a flat wire or a method of heat welding can be applied.
In the method of driving a flat wire, a plurality of bristles 21a are bundled and folded in half, and a hair retainer 21 called a flat wire is sandwiched therebetween and driven into a flocked hole, thereby flocking the hair bundle 21 into each flocked hole.
The flat line is placed in the flock hole so as to pass through the center of the flock hole and straddle the flock hole. Examples of the material of the flat wire include metals such as brass and stainless steel, and other examples include hard plastic and biodegradable plastic.
The length, width, and thickness of the flat line may be arbitrarily adjusted according to the hair bundle 21 and the flocked hole. Usually, the length of the flat line is larger than the diameter of the flocked hole, and the width of the flat line is It is made smaller than the depth of the pores. Moreover, by adjusting the thickness of the flat wire, the hair bundle 21 can be securely fixed in the flock hole and the gap can be reduced. Further, in order to prevent the flat wire from coming out of the flocked hole, the total length of the portions protruding from both sides of the flocked hole is preferably 0.3 to 0.6 mm.

The material of the head part 20 and the handle body 10 can be determined in consideration of the rigidity and mechanical characteristics required for the head part 20 and the handle body 10, for example, a resin having a flexural modulus (JIS K7203) of 500 MPa or more (hereinafter, a hard resin). And a resin having a 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 3000 MPa. Specifically, for example, the flexural modulus of the material of the head portion 20 and the handle body 10 can be selected from the range of 500 to 3000 MPa, preferably 700 to 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), polyacetal (POM), and polyethylene naphthalate (PEN). ), Polystyrene (PS), acrylonitrile / butadiene / styrene resin (ABS), cellulose propionate (CP), polyarylate, polycarbonate, or acrylonitrile / styrene copolymer resin (AS). POM, PEN, PBT, PCT or the like as described above is preferable. By using a resin having a flexural modulus of 2000 MPa or more, the head portion 20 can be thinned, the operability in the oral cavity can be improved, and the handle body 10 can be prevented from being damaged.

Moreover, the handle body 10 may be partially or entirely covered with a soft resin. Since part or all of the handle body 10 is covered with the soft resin, the fit of the hand when the user grips the handle body 10 is improved, and the gripped fingers can be prevented from slipping.
Examples of the soft resin include resins having a Shore hardness of A90 or less, more preferably resins having a Shore hardness of A30 to 80. Examples of such soft resins include elastomer resins such as polyolefin-based elastomers, styrene-based elastomers, polyester-based elastomers, and polyurethane-based thermoplastic elastomers, and silicon.

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

(Example 1, Comparative Examples 1 and 2)
Polycyclohexylenedimethylene terephthalate resin (product name: Easter BR203, flexural strength: 68 MPa, flexural modulus: 1900 MPa, manufactured by Eastman Chemical Co., Ltd.) was injection molded to obtain an integrally molded product of the head portion and the handle body. . The diameter of the flocked hole is 1.5 mm, and the arrangement of the flocked holes is 2 holes × 1 row, 3 holes × 1 row, 4 holes × 5 rows, 3 holes × 1 row from the tip of the head part toward the handle body. It was.
Next, a hair bundle of taper hairs (7.5 mils) made of a polybutylene terephthalate filament shown in Table 1 was implanted in the head portion by flat wire flocking to produce a toothbrush.

In addition, the zero shear viscosity of the filament and the elongation at break per unit area were measured as follows. The measurement results are shown in Table 1. [Zero shear viscosity]
Using a dynamic viscoelasticity measuring device (AR-2000ex manufactured by TA Instruments Inc.) equipped with a cone-disk (cone angle 4 °, cone diameter 25 mm) as a measurement sample jig, a frequency-dependent mode The dynamic viscoelasticity was measured at 240 ° C. As a result, a graph was created 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 obtained by interpolation. The loss elastic modulus when N was 0 was defined as zero shear viscosity.
[Elongation at break per unit area]
The elongation at break per unit area was determined from the following formula (1) by conducting a tensile test of the filament using an autograph manufactured by Shimadzu Corporation.
Breaking elongation per unit area (%) = breaking elongation (%) / cross-sectional area (mm ² ) (1)
The tensile test conditions were a measurement temperature of 25 ° C., a tensile speed of 20 mm / min, and a distance between chucks (test clamping jigs) of 5 mm. The top view of the test piece used for the tensile test of this measurement is shown in the figure. Further, as shown in FIG. 2, a chuck was attached to a portion excluding the portion A between A and 2.5 mm from the intermediate point C.

<Evaluation>
In each of the toothbrushes, the durability against breaking and the opening durability were evaluated. The evaluation results are shown in Table 1.

[Durability of broken hair]
A test solution in which a commercially available dentifrice was dispersed in water was set at 35 ° C., and the toothbrush was repeatedly reciprocated while pressing the hair bundle against a metal corrugated plate in the test solution. The test conditions at that time were a load of 300 g, a brushing stroke of 40 mm, a reciprocating speed of 160 times / minute, and a number of times of brushing of 150,000 times. Thereafter, the number of breaks per toothbrush after brushing, that is, the number of broken hairs, was measured using a microscope. The column of “number of broken hairs” in Table 1 shows an average value obtained by measuring the number of broken hairs for five measured toothbrushes. The smaller the number of broken hairs, the higher the durability of broken hairs.

[Drilling durability]
The width of the flocked portion in the direction of the minor axis of the toothbrush before and after the brushing was measured, the width of the bristles spread after the brushing was calculated, and the ratio to the width of the flocked portion in the initial state was determined. Based on the ratio, the hair opening was evaluated according to the following criteria.
◎: Less than 20% ○: 20% or more and less than -60% △: 60% or more and -100% or less ×: More than 100%

The toothbrush of Example 1 using the PBT tapered bristles having a zero shear viscosity in the range of 200 to 300 Pa · s and a breaking elongation per unit area of 2600% or less was less likely to bend and open. .
On the other hand, the toothbrush of the comparative example 1 using the PBT taper hair whose zero shear viscosity is less than 200 Pa * s was easy to break.
On the other hand, the toothbrush of the comparative example 2 using the PBT taper bristle whose break elongation per unit area exceeded 2600% was easy to open.

DESCRIPTION OF SYMBOLS 1 Toothbrush 10 Handle body 20 Head part 20a Flocked surface 21 Hair bundle 21a Hair for hair

Claims

In a toothbrush having a handle body and a head portion extending to the tip of the handle body, and a plurality of hair bundles having a plurality of hairs implanted in the head portion,
All or a part of the plurality of hairs is a filament composed of polybutylene terephthalate,
The filament has a zero shear viscosity at 240 ° C. in the range of 200 to 300 Pa · s, and the elongation at break measured per unit area measured using a tensile tester at a measurement temperature of 25 ° C. and a tensile speed of 20 mm / min. A toothbrush having a degree of 2600% or less.
The toothbrush according to claim 1, wherein the filament has a zero shear viscosity at 240 ° C in the range of 260 to 280 Pa · s.
The toothbrush according to claim 1 or 2, wherein the elongation at break per unit area measured at a measurement temperature of 25 ° C and a tensile speed of 20 mm / min using the filament tensile tester is 2500% or less.
The toothbrush according to any one of claims 1 to 3, wherein the bristles have a substantially circular cross section and a thickness of 4 to 10 mils.