KR20160102149A - Toothbrush - Google Patents

Abstract

Prevention of wrinkles and wrinkles when the toothbrush is repeatedly used over a long period of time. The toothbrush 1 has a handle 10 and a head 20 extending from the tip of the handle 10. The head 21 has a plurality of bristles 21 of a plurality of bristles 21a , All or a part of the bristles (21a) is made of a filament made of polybutylene terephthalate, and the filament has a zero shear viscosity at 240 ° C in the range of 200 to 300 Pa · s, Is 2600% or less.

Description

Toothbrush {TOOTHBRUSH}

The present invention relates to a toothbrush.

Priority is claimed on Japanese Patent Application No. 2013-262893, filed on December 19, 2013, the entire contents of which are incorporated herein by reference.

To prevent periodontal disease, removal of jig cervical is important. Therefore, in order to improve the cleaning property of the cervical portion by the toothbrush, in particular, the periodontal pocket, a so-called tapered bristle is used as the toothbrush or a thin bristle is used as the toothbrush (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 bristles are folded in the vicinity of the corners of the corners. Particularly, this problem was remarkable when a polyester resin was used as a raw material of the bristles. In addition, the uprightness of the bristles deteriorates, and when viewed from the plane, there is a case where the area surrounded by the outermost bristles is worn as compared with when unused.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to prevent wrinkles and wrinkles when the toothbrush is repeatedly used over a long period of time.

A toothbrush according to an embodiment of the present invention includes a handle body and a head portion extending from the tip of the handle body, and the head portion has a plurality of bristles each having a plurality of bristles, wherein all or a part of the plurality of bristles Is a filament having polybutylene terephthalate as a constituent material. The filament has a zero shear viscosity at 240 占 폚 in the range of 200 to 300 Pa 占 퐏, and has a fracture elongation per unit area determined by the following formula (1) Is 2600% or less.

Breaking elongation per unit area (%) = elongation at break (%) / sectional area (mm 2) (1)

The elongation at break was measured using a tensile tester under the measurement conditions of a measurement temperature of 25 DEG C and a tensile speed of 20 mm / min. The cross-sectional area is the cross-sectional area of the thickest portion described later.

Further, in the toothbrush according to another embodiment of the present invention, the filament has a zero shear viscosity at 240 캜 of 260 to 280 Pa · s.

Further, the toothbrush according to another embodiment of the present invention has a breaking elongation per unit area of 2500% or less as measured at a measurement temperature of 25 DEG C and a tensile speed of 20 mm / min using a tensile tester of the filament.

Further, 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 the wrinkles and wrinkles when the toothbrush is repeatedly used over a long period of time.

1 is a side view showing one embodiment of a toothbrush of the present invention.
Fig. 2 is a schematic diagram for explaining a tensile test in Examples and Comparative Examples. Fig.

One embodiment of the toothbrush of the present invention will be described.

Fig. 1 shows a side view of the toothbrush of this embodiment. The toothbrush 1 of the present embodiment has a handle body 10 and a head portion 20 extending to the handle body 10 and is integrally formed with the head portion 20 and is provided with a plurality of bristles 21a A plurality of mother ships 21 are arranged.

The head portion 20 has a substantially quadrangular plate shape in which the corner portion of the handle portion 10 is curved at a corner when viewed from the plane, (20a) is formed with a plurality of openings. And a hair follicle 21 is formed on the hair follicle hole to form a hair follicle section composed of a plurality of hair follicles 21. [

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

If the size of the head portion 20 in the width direction is excessively long, the operability in the oral cavity is deteriorated. If the head portion 20 is too short, the number of hair pieces 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, for example, 5 to 13 mm. Here, the width of the head portion is the width of the portion having the largest width. For example, when the width of the vicinity of the tip of the head portion is small due to a rounded structure or the like, the width is the width of the portion excluding the portion.

The thinner the size of the head portion 20 in the thickness direction, the greater the operability in the mouth. However, if the head portion 20 is too thin, the strength of the head portion 20 tends to become insufficient. Therefore, the thickness of the head portion 20 can be determined in consideration of the material of the handle 10, and is preferably, for example, 1.5 to 5 mm, more preferably 2 to 3 mm. Here, the thickness of the head portion is the thickness of the portion having the largest thickness. For example, when the thickness near the edge of the head portion is reduced by a round structure or the like, it is the thickness of the portion excluding the portion.

If the size of the head portion 20 in the longitudinal direction is too long, the operability in the oral cavity tends to be damaged. If the head portion 20 is too short, the number of hair loops 21 to be implanted is too small, and the cleaning effect tends 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 circular shape such as a circle or an ellipse, and a polygon such as a triangle or a square.

The number of holes of the flocked hole is not particularly limited, and is, for example, 10 to 60 holes.

The diameter of the hair-removal hole is determined according to the thickness of the required hair 21, and is, for example, 1 to 3 mm.

The arrangement pattern of the flock holes is not particularly limited and may be any arrangement pattern such as a so-called checkerboard pattern or a zigzag pattern (also referred to as a stagger pattern).

All or a part of the plurality of bristles 21a in this embodiment is a filament made of polybutylene terephthalate (PBT). The bristles 21a are filaments made of polybutylene terephthalate as a constituent material, which means that the fine lines comprising polybutylene terephthalate as a constituent material are used as they are as bristles. Here, when polybutylene terephthalate is used as the constituent material, it means that the constituent material of the filament is almost composed of polybutylene terephthalate except impurities and the like, specifically 90 to 100% by weight is polybutyl It is preferable that it is a rheneterephthalate. When the resin constituting the filament is polybutylene terephthalate, tapered filaments can be easily produced by a manufacturing means such as a chemical treatment.

The whole or a part of the plurality of bristles 21a is a filament made of polybutylene terephthalate as a constituent material because the polybutylene terephthalate among a plurality of bristles 21a included in the hair blades 21 It is preferable that the filaments are contained in a number of 25% or more with respect to the total number of bristles 21a included in the hair 21.

The shape of the bristles 21a may be a straight shape having the same diameter throughout the lengthwise direction, or a tapered shape tapering toward the hair end. In order to further improve the cleaning property of the cervical portion, the bristles 21a are preferably tapered bristles (tapered bristles).

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

The filament in the present embodiment preferably has a zero shear viscosity at 240 캜 in the range of 200 to 300 Pa · s and in the range of 260 to 280 Pa · s. If the zero shear viscosity is lower than the above lower limit value, it is likely to be broken. Further, if the zero shear viscosity of the filament exceeds the upper limit value, the formability at the time of extrusion molding tends to be lowered in obtaining the filament, and in the case of tapering, productivity tends to decrease.

The zero shear viscosity in this embodiment is obtained by measuring the dynamic viscoelasticity at 240 占 폚. The dynamic viscoelasticity measurement (or DMA) is a measurement that applies a force that varies with time to a sample and determines a change in elastic modulus from a change in the strain generated by the sample.

Specifically, a graph in which the abscissa is the angular frequency (ω) and the longitudinal axis is the loss elastic modulus (G ") is prepared by measuring the dynamic viscoelasticity at 240 ° C. and the loss elastic modulus The loss elastic modulus when the frequency (omega) is 0 is defined as the zero shear viscosity.

Further, for example, in the case of a filament composed of polybutylene terephthalate, the zero shear viscosity is proportional to 3.4 times the weight average molecular weight of the above-mentioned polybutylene terephthalate molecule. Therefore, the compound Of the weight average molecular weight. That is, the larger the zero shear viscosity, the larger the weight average molecular weight of the compound.

The filament of the present embodiment preferably has a breaking elongation per unit area of 2600% or less and 2500% or less.

Here, the elongation at break per unit area is a value expressed by the following formula (1).

Breaking elongation per unit area (%) = elongation at break (%) / sectional area (mm 2) (1)

The cross-sectional area of the filament is, for example, the cross-sectional area at a cross section (transverse section) where the filament is cut at the thickest position and perpendicular to the longitudinal direction. The thickest position means, for example, the tapered shape of the filament, which means that the filament is thin (cross-sectional area is small) at both ends, excluding thin portions at both ends thereof. Examples are the average of cross-sectional areas of 50 to 90% of the length including the center in the length direction of the filament, excluding the fine portions at both ends described above. 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 frame of the molded device).

When the elongation at break per unit area of the filaments exceeds the upper limit value, wicking tends to occur. On the other hand, considering the strength and thickness required for filaments generally used in toothbrushes, the elongation at break 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 the measurement conditions of a measurement temperature of 25 占 폚 and a tensile speed of 20 mm / min. Here, the tensile tester can suitably use a device capable of exerting a force in the tensile direction (e.g., in the direction of stretching the filament in the longitudinal direction in the filament of the present embodiment) with respect to the specimen. More specifically, it is possible to use a device capable of measuring the force at the time of fracture of the sample and the rate of change of the length of the sample by applying a tensile force to the sample at a predetermined extension rate. As an example of the tensile tester, an autograph tester or the like can be preferably used.

Further, in the present embodiment, it is preferable that filaments satisfying the conditions of the zero shear viscosity and the elongation per unit area include 50% or more of the bristles 21a.

The elongation at break of the filament is influenced by the spinning conditions at the time of filament production. Therefore, in order to set the elongation at break within the above range, the elongation and the heat treatment conditions in the spinning process may be appropriately adjusted.

The cross-sectional shape obtained by cutting the bristles 21a at an arbitrary position in the longitudinal direction in the longitudinal direction is not particularly limited and may be circular, polygonal, star-shaped, three-leaf-clover, good.

The thickness of the bristles 21a can be determined in consideration of the material and the like. When the cross section is circular, for example, 4 to 10 mil (1 mil = 1/1000 inch = 0.025 mm) is obtained. In addition, a plurality of bristles 21a having different thicknesses or cross-sectional shapes may be arbitrarily used in consideration of feeling of use, chain sawing, cleaning effect, or durability.

As a method of setting the mother wire 21, a known method such as a method of pulling in a flat wire or a method of heat welding can be applied.

In the method of inserting the flat lines, a plurality of bristles 21a are folded and folded in half, a fastener called a flat line is sandwiched therebetween, and the bristles 21 are inserted into the respective flatting holes.

The flat line passes through the central portion of the flocking hole and is laid on the flocking hole so as to cover the flocking hole. As the material of the flat wire, for example, metal such as brass or stainless steel can be mentioned, and hard plastic or biodegradable plastic can be mentioned.

The length, width, and thickness of the flat lines may be arbitrarily adjusted in accordance with the blind spots 21 or the flocked holes, but the length of the flat lines is usually larger than the diameter of the flocked holes and the width of the flat lines is smaller than the depth of the flocked holes. In addition, by controlling the thickness of the flat line, it is possible to reliably fix the blind spiral 21 in the flat bottom and reduce the air gap. It is preferable that the sum of the lengths of the protruding portions from both sides of the flocked hole is 0.3 to 0.6 mm in order to prevent the flattening from coming out of the flocked hole.

The material of the head portion 20 and the handle 10 can be determined in consideration of the stiffness and the mechanical characteristics required of the head portion 20 and the handle 10 and the bending elastic modulus (JIS K7203) 500 (Hereinafter sometimes referred to as a hard resin) is preferable, and a resin having a flexural modulus of 700 MPa or more is more preferable. The upper limit of the bending elastic modulus of the resin used for the head portion 20 and the handle 10 is not particularly limited, but is, for example, 3000 MPa. Specifically, for example, the bending elastic modulus of the material of the head portion 20 and the handle 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), polycyclohexylenedimethylene terephthalate (PCT) (PS), acrylonitrile-butadiene-styrene resin (ABS), cellulose propionate (CP), polyarylate, polycarbonate or acrylonitrile-styrene copolymer resin (AS), polyethylene naphthalate (PEN), polystyrene Among them, POM, PEN, PBT or PCT having a bending modulus of 2,000 MPa or more is preferable. By using a resin having a bending elastic modulus of 2000 MPa or more, the head 20 can be thinned to improve operability in the oral cavity, and breakage of the handle 10 can be prevented.

The handle body 10 may be partially or entirely covered with a soft resin. A part or the whole of the handle body 10 is covered with the soft resin so that the fit feeling of the hand when the user holds the handle body 10 is improved and the gripped finger can be prevented from slipping.

As the flexible resin, for example, a resin having a Shore hardness A90 or less, more preferably a resin having a Shore hardness A30 to 80 can be given. Examples of the soft resin include an elastomer resin such as a polyolefin elastomer, a styrene elastomer, a polyester elastomer or a polyurethane thermoplastic elastomer, or silicon.

As described above, the toothbrush of the present embodiment has a zero shear viscosity at 240 ° C in the range of 200 to 300 Pa · s and a filament made of polybutylene terephthalate having a breaking elongation per unit area of 2600% or less Therefore, it is prevented from being worn and worn.

Example

(Example 1, Comparative Examples 1 and 2)

Polycyclohexylenedimethylene terephthalate resin (product name: ISTA BR203, bending strength: 68 MPa, bending elastic modulus: 1900 MPa, manufactured by Eastman Chemical Company) was injection-molded to obtain an integral molded body of the head part and the handle body. The diameter of the flocked holes was 1.5 mm, and the arrangement of the flocked holes was 2 pore x 1 column, 3 pore x 1 column, 4 pore x 5 column and 3 pore x 1 column respectively from the tip of the head toward the steering wheel.

Then, the hair of the tapered bristles (7.5 mil) made of the polybutylene terephthalate-made filament shown in Table 1 was stuck to the head portion by flat wire type floss to prepare a toothbrush.

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]

Dynamic viscoelasticity was measured at 240 ° C in a frequency-dependent mode using a dynamic viscoelasticity measuring apparatus (AR-2000ex, manufactured by TI Instrument Co., Ltd.) equipped with a cone-disc (conical angle of 4 degrees, conical diameter of 25 mm) Respectively. As a result, a graph in which the abscissa represents the angular frequency (?) And the ordinate represents the loss elastic modulus (G ") is prepared and the loss elastic modulus when the angular frequency (?) Is 0 is obtained by interpolation from the graph. and the loss elastic modulus when the elastic modulus (?) was 0 was defined as the zero shear viscosity.

[Breaking elongation per unit area]

The elongation at break per unit area was determined by the following formula (1) by performing a tensile test on filaments using Autograph of Shimadzu Corporation.

Breaking elongation per unit area (%) = elongation at break (%) / sectional area (mm 2) (1)

The conditions of the tensile test were a measurement temperature of 25 占 폚, a tensile speed of 20 mm / min, and a distance between the chucks (test jig) of 5 mm. A plan view of the test piece used in the tensile test of this measurement is shown in the figure. Further, as shown in Fig. 2, a chuck was attached to a portion except for a portion between the portions A and A of 2.5 mm from the midpoint C.

<Evaluation>

In each of the toothbrushes, the durability and the durability were evaluated. The evaluation results are shown in Table 1.

[Modified durability]

The test liquid in which a commercially available toothpaste agent was dispersed in water was set at 35 占 폚, and toothbrushes were repeatedly reciprocated in a test solution while being pressed against a metal wavy plate. The test conditions at that time were a load of 300 g, a crushing stroke of 40 mm, a reciprocating speed of 160 times / minute, and a number of times of crushing of 150,000 times. Thereafter, using a microscope, the number of fractures per one toothbrush after the tooth brushing, that is, the number of bumps was measured. Table 1 shows the average value of the number of teeth measured for five measured toothbrushes. The smaller the number of bumps, the higher the durability.

[Wearing durability]

The breadth of the floss in the direction of the short axis of the toothbrush before and after the bran was measured, and the breadth of the bran at the end of the bran was calculated to determine the ratio to the width of the floss in the initial state. Based on the ratio, the wake was evaluated based on the following criteria.

◎: Less than 20%

○: 20% or more to less than 60%

?: 60% or more to -100% or less

×: exceeding 100%

The toothbrush of Example 1 using a PBT tapered tooth having a zero shear viscosity in the range of 200 to 300 Pa · s and a fracture elongation per unit area of 2600% or less was hardly generated in the toothbrush.

On the other hand, the toothbrush of Comparative Example 1 using a PBT tapered eye having a zero shear viscosity of less than 200 Pa · s was easily prone to breakage.

On the other hand, the toothbrush of Comparative Example 2 using a PBT tapered tooth with a break elongation per unit area exceeding 2600% was prone to wilting.

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

Claims (4)

A toothbrush comprising a handle body and a head portion extending from a distal end of the handle body, the head having a plurality of bristles having a plurality of bristles,
Wherein all or a part of the plurality of bristles is a filament having polybutylene terephthalate as a constituent material,
The filament has a zero shear viscosity at 240 ° C in the range of 200 to 300 Pa · s and a tensile elongation per unit area measured at a measuring temperature of 25 ° C. and a tensile speed of 20 mm / Is less than or equal to 2600%. The method according to claim 1,
Wherein the filament has a zero shear viscosity at 240 占 폚 in the range of 260 to 280 Pa 占 퐏. 3. The method according to claim 1 or 2,
Wherein a tensile elongation per unit area measured at a measurement temperature of 25 DEG C and a tensile speed of 20 mm / min using a tensile tester of the filament is 2500% or less. 4. The method according to any one of claims 1 to 3,
Wherein the bristles are substantially circular in cross-section and have a thickness of 4 to 10 mils.

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