RU2430668C2 - Bristle for toothbrush with narrowing part and toothbrush with such bristle - Google Patents

Abstract

FIELD: personal use articles. ^ SUBSTANCE: bristle for a toothbrush comprises a cylindrical part (1) with maximum permanent diameter Dzyl, the first narrowing part (21) adjacent to the cylindrical part (1) and having the end (3) of the bristle and finishing the end (3) of the bristle with the end surface (4). The first narrowing part (21) narrows to the end (3) of the bristle. An imaginary middle axis (5) passes through the cylindrical part (1) and the first narrowing part (21), and also passes through the end surface (4) in the point (6) of passing. The first narrowing part (21) has the length L measured on the middle axis (5) from the point (6), equal to 10 mm or less, and at least 3 mm. The first narrowing part (21) has diameter D from 95 to 140 mcm at the distance X measured on the middle axis (5) from the point of passing (6), equal to the cylinder diameter Dzyl. A toothbrush with such bristle is provided. ^ EFFECT: invention increases bristle durability and improves its cleaning properties. ^ 10 cl, 6 dwg

Description

This invention relates to a bristle for a toothbrush with a tapering part, as well as to a toothbrush with such a bristle.

The classic toothbrush bristle has a cylindrical cross section. Since such a bristle has insufficient cleaning ability in the interdental space and is prone to damage the gums, in the 90s of the last century partially switched to supplying the bristles with pointed ends (see EP-A-0 596 633). Due to the smaller cross section at the pointed end, the cleaning ability in the interdental space is improved; accordingly, the bristles become more flexible due to this, which reduces the risk of damage. On the other hand, the cleaning ability on the tooth surfaces has decreased.

Korean patent KR 261658 (corresponding to US-A-6 090 488) describes a bristle for a toothbrush, wherein the bristles at the end of the tapering portion have a diameter of 0.04 to 0.08 mm. Thus, the tapering part of this bristle is no longer pointed in the above sense. However, a later patent EP-A-1 234 525 of the same inventor describes a bristle with a tapering part, in which the diameter at the end of the tapering part is only 0.02 mm or less (i.e., this bristle is rather similar to a pointed bristle, according to EP-A-0 596 633). To justify that he again reduced the diameter at the end of the bristles, the inventor indicates that using the bristles, according to KR 261658, it is difficult to remove tartar from periodontal pockets.

The present invention has the task of creating improved bristles with a tapering part.

The problem is solved according to the invention using a bristle for a toothbrush containing:

a) a cylindrical part with a maximum constant diameter D _zyl ;

b) adjacent to the cylindrical part of the first tapering part with the end of the bristles and the end surface of the bristles end surface, while the first tapering part tapers to the end of the bristles; and

c) an imaginary middle axis passing through the cylindrical part and the first tapering part, which passes through the end surface at the point of passage;

wherein the first tapering portion has a length L, measured on the middle axis from the point of passage, of 10 mm or less and at least 3 mm,

which is characterized in that the first tapering part has, at a distance X, measured on the middle axis from the point of passage, equal to the diameter D _{zyl of the} cylinder, the diameter D from 95 to 140 microns.

Preferred embodiments follow from the dependent claims.

Unexpectedly, it was found that the bristles according to the invention have a longer service life than the previously known pointed bristles: the pointed bristles are bent, as the applicant has established, under the action of pressing forces arising from brushing teeth, which eventually leads to fatigue destruction of the bristle tip; this is prevented by only tapering (not pointed) bristles according to the invention. At the same time, it was found that the bristles according to the invention are mechanically so stable that they exhibit comparable to a cylindrical bristles and even slightly superior cleaning ability on the buccal tooth surfaces. In addition, the bristles according to the invention are better suited for cleaning interdental spaces and adjacent tooth surfaces than bristles with non-tapering ends of the bristles, since the bristles according to the invention can better reach adjacent tooth surfaces.

Preferably, the diameter D is in the range of 100 to 130 μm, more preferably in the range of 100 to 125 μm. Also preferably, the first tapering part of the bristles has a diameter of 120 to 160 μm at a distance of 1 mm, measured on the middle axis from the point of passage, and a diameter of 90 to 135 mm at a distance of 0.1 mm measured in the same way.

The bristles according to the invention are essentially (or as technically as possible) rotationally symmetrical around the mid-axis.

The profile line of the tapering part of the bristle (i.e., the diameter of the tapering part, depending on the decreasing distance from the point of passage of the middle axis of the bristles through the end surface) preferably passes with a monotonic fall to the end surface. The concept of "monotonous fall" in the framework of this invention is common in mathematics. More preferably, the profile line of the tapering part in the mathematical sense is strictly monotonously falling.

The length of the tapering part (i.e. in the case of a U-shaped bristle with two tapering parts, the length of both tapering parts) is preferably in the range of 6 to 10 mm.

The end surface of the end of the first tapering part has at the indicated point of passage normal to a surface that is inclined relative to the specified middle axis, preferably not more than 30 °. This, as a rule, automatically takes place when the end surface is formed by aligning the pointed end (see below); this can also be caused by suitable rounding processing of the end surface and its adjacent edges along the tapering part of the edges (see below).

Three particularly preferred types of bristles according to the invention are as follows:

i) a bristle with a cylindrical portion adjacent to exactly one substantially rotationally symmetric tapering portion 10 mm or less in length (i.e., similar to a bristle sharpened on one side);

ii) a bristle with a cylindrical part, to which exactly two essentially rotationally symmetric tapering parts adjacent to a length of 10 mm or less adjoin which adjoin on the opposite sides to the cylindrical part (i.e., similar to a bristle sharpened on both sides), in particular both tapering parts are essentially uniformly formed, and

iii) a bristle with a cylindrical part, a substantially rotationally symmetrical tapering part of a length of 10 mm or less and a substantially rotationally symmetrically pointed end, wherein the tapering part and the pointed part adjoin the cylindrical part on opposite sides.

In all embodiments of the bristles according to the invention, all existing edges between the end surface and the tapering part can be removed by rounding, as is usually done with a cylindrical bristle. Rounding can be carried out using conventional known methods, for example, using sandpaper.

Particularly preferred profile lines of the first tapering part follow from the following profile tables 1-3. The diameters are indicated depending on the distance from the point of passage of the midline through the end surface (average values with dispersion of 6 specimens of bristles). The _rightmost column of each table indicates the maximum diameter of the cylindrical part (D _zyl ) of the bristles. In accordance with the definition of the measurement according to the invention, the diameter D of the first tapering part in each table indicates the corresponding value of the diameter at a distance X = D _zyl . In addition, profile diameters 1-3 also indicate diameter values at a distance of 0.1 mm from the end surface as an example of the preferred embodiment of the invention when the first tapering portion passes near the end surface.

Profile 1

The distance from the pointed end, in mm 0 0.1 0.202 one 2 3 four 5 6 7 8 9 10 Diameter in mm 0.107
(0.108) 0.113 0.117 0.147 0.172 0.183 0.190 0.195 0.197 0.199 0.201 0,203 0.202 Diameter range, in +/- mm 0.012 0.019 0,021 0,020 0.019 0.014 0.014 0.014 0.012 0.011 0.010

Profile 2

The distance from the pointed end, in mm 0 0.1 0.202 one 2 3 four 5 6 7 8 9 10 eleven Diameter in mm 0,086
(0,089) 0,095 0,101 0.140 0.172 0.185 0.192 0.198 0.201 0.204 0.205 0.205 0.208 0.209 Diameter range, in +/- mm 0.012 0.009 0.009 0.008 0.007 0.006 0.008 0.005 0.006 0.006 0.005 0.006

Profile 3

The distance from the pointed end, in mm 0 0.1 0.209 one 2 3 four 5 6 7 8 9 10 Diameter in mm 0,086
(0,098) 0,101 0.104 0.127 0.151 0.170 0.183 0.191 0.199 0.202 0.206 0.283 0.209 Diameter range, in +/- mm 0.009 0.009 0.009 0.008 0.007 0.006 0.008 0.005 0.006 0.005 0.003

Profile 4

The distance from the pointed end, in mm 0 0.1 0.166 one 2 3 four 5 6 7 8 9 10 Diameter in mm 0,112
(0,117) 0.119 0.122 0.137 0.150 0.156 0.159 0.162 0.164 0.165 0.165 0.165 0.165 Diameter range, in +/- mm 0.009 0.011 0.009 0.009 0.008 0.007 0.007 0.007 0.007 0.007 0.007

It may happen that in some embodiments according to the invention, the diameter at the end surface or at a small distance from the end surface cannot be reasonably measured. This is the case when the end of the bristles of the tapering part was subjected to subsequent rounding. This rounding may, under certain circumstances, leave unevenly curved shapes and non-planar surfaces at the end of the bristles, which makes it impossible to directly measure the diameter near the end surface. In a bristle according to the invention, it was also unexpectedly found that in these cases the diameter near or at the end surface can be approximately determined by extrapolation with a parabola, while for the parabola, the diameter of the bristles at a distance of 1, 2 and 3 mm from the end surface is taken as reference points. These reference points are indicated in bold in the above tables. To prove this, the above tables at a distance of 0 from the end surface indicate both the initial, actually measured bristle diameters (after alignment of the end, but before rounding), and the diameters determined using this extrapolation, indicated in parentheses below. Deviations between the actual diameters and the diameters determined by extrapolation are minimal. Such a simple extrapolation for the bristles according to the invention is possible because the curvature of the tapering part is less pronounced than in the previously known bristles.

The bristles according to the invention consist of plastic suitable for toothbrush bristles. It can consist, on the one hand, preferably of a polyester, in particular of a polyester, which is obtained from (C ₂ -C ₄ ) -1, ω-alkylene glycol) and terephthalic acid. More preferred is polyester polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), and particularly preferably PBT. On the other hand, it may consist of polyamide, in particular polyamide, which is obtained from (C ₂ -C ₈ ) -1, ω-diamine and (C ₂ -C ₈ ) -1, ω-dicarboxylic acid; particularly preferred in this case is polyamide-6,6 (e.g. nylon).

For the manufacture of bristles according to the invention, one can start from commercially available single or double-pointed bristles. At the time of filing this application, the manufacturers of such bristles were Pragma, Shinoung, Wessen, Hylon, Sago, Best Whasung or Cheil Jedang.

A bristle according to the invention, which has exactly one first tapered end, can be obtained, for example, from a commercially available one-sided pointed bristle by aligning the tapered end while forming a tapered end and an end surface. In order for the bristles to have a generally suitable length for the toothbrush bristles, the other, cylindrical end of the bristles can be cut accordingly.

The bristles according to the invention, which, along with the first tapering end, have a second tapering end or a pointed part, can usually be made from commercially available bristles of suitable length by giving the ends by chemical etching a suitable tapering or pointed shape. This etching method has long been known for the manufacture of pointed bristles. In this case, the tapering end may not necessarily be aligned to set a suitable overall bristle length.

On the other hand, a commercially available double-pointed bristle is proposed which only needs to be properly aligned at both ends in order to obtain a bristle according to the invention with two pointed parts and a length suitable for a toothbrush (see Example 1).

In the chemical etching method, the bristles can first be aligned to a single length. After that, it can be etched by vertical immersion in an etching liquid with a temperature of usually 80-150 ° C. Examples of etching liquids are inorganic solutions, for example, a highly alkaline etching solution (for example, a 25-50 wt.% Aqueous solution of NaOH or KOH) or a strongly alkaline etching solution (for example, a 60-98 wt.% Aqueous solution of sulfuric acid). Organic solvents are also examples of etching liquids, such as, for example, m-cresol, trifluoroacetic acid, o-chlorophenol, trichlorophenol, DMSO, DMF, and a mixture of phenol and tetrachloroethane. The duration of immersion can usually be 10-20 minutes, while the bristles can be removed during this time from the etching liquid at a freely selectable, constant or time-varying speed, due to which it can affect the profile of the etched end (for example, monotony of the profile line). After etching, the ends can be washed depending on the etching liquid with water, a diluted base, a diluted acid or a suitable solvent at ordinary room temperature and dried.

The etching conditions (type and temperature of the etching liquid, the duration of immersion) can, on the one hand, be chosen so that the diameter D of the tapering part after etching lies precisely in the range according to the invention from 100 to 140 μm. To do this, etching is carried out in a shorter period of time than when etching known pointed bristles. On the other hand, the conditions can be chosen so that to obtain the end surface and the tapering part, alignment is performed.

If desired, the bristle ends can be leveled after etching in an alkaline or acid solution before rounding the ends. The need for alignment of the ends can be determined by simply examining the condition of the ends with a magnifying device after extraction from the solution.

A subject of the invention is also a toothbrush with bristles according to this invention. The bristles according to the invention can be installed similarly to the one- or two-sided pointed bristles in the toothbrush bristle support. In this case, the bristles with two tapering parts or with one tapering part and one pointed part are preferably bent U-shaped and set with the help of an anchor plate into the bristle support. The bristles according to the invention with only one tapering part and one cylindrical part are installed in contrast to this, preferably in a non-bent form, using the so-called AFT method (Anchor-Free Tufting = firmware without anchor) in the bristle support.

The following is a detailed explanation of the invention based on examples and with reference to the accompanying drawings, which depict:

figure 1 - section of the bristles according to the invention, indicating the essential for the invention measuring parameters;

figure 2, 3 and 4 are three options for performing bristles according to the invention; and

5 and 6 are in vitro tests of the cleaning ability for teeth stained black, then coated with a layer of TiO ₂ using the invention and a conventional cylindrical bristle.

Example 1: Production of bristles with two identical tapering parts, according to the above tables of profiles 1-4

We proceeded from a commercially available, on two sides, pointed bristles, which was as follows:

Source bristles Aligned in distance
from the tops, in mm For profile table number Pragma 0.18 × 28 mm
033004 A-Air Force 2 one Pragma 0.19 × 28 mm
033004 A-Air Force one 2 Shinyoung 0.20 × 28 mm 2 3 Wessen 0.18 × 24 mm 2 four

Each initial bristle was aligned at both vertices at the distances indicated in the above table in the middle column. The ends of the tapering bristle ends thus obtained were rounded, and a TR89 bristle rounding machine (manufactured by the Japanese company Tsujimura Co.) with sandpaper 240 was used.

Figure 1 shows the end with a tapering part of the bristles according to the invention. On the right, the cylindrical part 1 is schematically shown, the constant diameter of which at the same time is the maximum diameter D _{zyl of the} bristles. The tapering part 21 is adjacent to the cylindrical part 1, the narrowing of which begins at a distance L from the point 6 of passage along the middle axis 5 of the end surface 4 and runs strictly monotonously to the end 3. The end surface 4 of the end 3 is shown here after idealizing rounding, i.e. approximately in the shape of a hemisphere; due to alignment and subsequent real rounding, the end surface can also be rather flat, but with more or less uneven and split edges. It is also shown that the diameter D essential for the invention is measured at a distance X from the passage point 6, while the distance X is exactly equal to the indicated maximum diameter D _{zyl of the} cylindrical part.

Figure 2-4 shows three bristles according to the invention. In all these drawings, the bristles are curved in a U-shape and mounted, as shown, in particular, in FIGS. 2 and 3, in the surface for the bristles of the toothbrush. The bending is carried out in the cylindrical part 1, which in this case is bent U-shaped. Figure 2 shows the bristles according to the invention with two tapering parts 21, 22; figure 3 shows the bristles according to the invention with one tapering part 21 and one pointed end 7; and FIG. 4 shows a bristle according to the invention with only one tapering part 21, with the remainder of the bristles formed by the cylindrical part 1. This last bristle can be inserted, unlike in FIG. 3, also in an unbent form into the support for the bristles of the toothbrush head .

Figures 5 and 6 show the results of tests on the cleaning ability, which were obtained in vitro on stained black, then coated with a layer of TiO ₂ teeth. In this test were subjected to:

(A) Brushes with a tapering on both sides according to the invention rotationally symmetric, U-shaped bent bristles installed in the brush (see FIG. 2) with a bristle field height of 11.5 mm, with a maximum diameter D _{zyl of} about 0.21 mm and with a diameter D of about 0.104 mm at a distance of X = D _zyl (this bristle corresponds to the profile 3 given in the tables as an example) and

(B) Brushes with a conventional cylindrical, U-shaped bent bristle installed in the brush with a diameter of D _zyl 0.175 mm and a bristle field height of 11.5 mm.

In these tests, the teeth of the upper jaw model with six teeth (3 molars, 2 molars, and 1 eye tooth) were first stained with black, and then stained with white using TiO ₂ paste (25 g in 75 ml of 26% ethanol). After a standard brushing process with a 1 minute bristle field to be tested with a clamping weight of 250 g, the surface fraction released from the TiO ₂ paste was determined. This process is carried out for each bristle field to be tested with horizontal, vertical and rotational cleaning movements and is repeated four times for each bristle field to be tested and for each cleaning movement. For horizontal cleaning (white stripes in the drawings), the standard brushing process consisted of 60 reciprocating movements with an amplitude of 30 mm; for vertical cleaning (shaded parts of strips in the drawings), the standard brushing process consisted of 60 movements up and down with an amplitude of 8 mm; and during rotational cleaning (dotted parts of the strips in the drawings), the standard brushing process consisted of 60 rotations with a radius of 4 mm while 16 reciprocating movements with an amplitude of 30 mm were simultaneously performed. 5 and 6, the fraction of TiO ₂ removed is shown in arbitrary units.

Figure 5 shows the sum of the average values of the cleaning abilities after horizontal, vertical and rotational cleaning movements using the bristles according to the invention (lane A), and using a conventional cylindrical bristle (lane B), on the buccal surfaces of the teeth.

Fig. 6 shows the sum of the average values of the cleaning abilities after horizontal, vertical and rotational cleaning movements with the bristles according to the invention (lane A), and with the help of a conventional cylindrical bristle (lane B), on the front / far surfaces of the teeth, i.e. on the surfaces of the teeth facing the interdental spaces.

From figure 5 it follows that the bristles according to the invention, despite lower mechanical strength, with horizontal and vertical brushing movements on the buccal surfaces of the teeth slightly exceeds conventional bristles. From Fig.6 it follows that the bristles according to the invention, in particular with horizontal and vertical brushing movements on the front / far surfaces of the teeth, are clearly superior to conventional bristles.

Claims (10)

1. A toothbrush bristle comprising:
a) a cylindrical part (1) with a maximum constant diameter D _zyl ;
b) the first tapering part (21) adjacent to the cylindrical part (1) with the bristle end (3) and the end surface (4) ending the bristle end (3), the first tapering part (21) tapering to the bristle end (3); and
c) an imaginary middle axis (5) passing through the cylindrical part (1) and the first tapering part (21), which passes through the end surface (4) at the point (6) of passage;
wherein the first tapering part (21) has a length L measured on the middle axis (5) from the passage point (6) of 10 mm or less and at least 3 mm,
characterized in that the first tapering part (21) has a diameter D from 95 to 140 μm at a distance X measured on the middle axis (5) from the passage point (6) equal to the diameter D _{zyl of the} cylinder. 2. The bristles according to claim 1, characterized in that the diameter D is in the range from 100 to 130 microns, preferably from 100 to 125 microns. 3. Bristle according to any one of claims 1 or 2, characterized in that the first tapering part (21) has a diameter of 120 to 160 μm at a distance of 1 mm, measured on the middle axis (5) from the passage point (6), and at a distance of 0.1 mm measured in the same way, a diameter of from 90 to 135 mm. 4. Bristle according to claim 1, characterized in that it has a second tapering part (22), which is adjacent to the cylindrical part (1) on the opposite first tapering part (21). 5. Bristle according to claim 4, characterized in that the second tapering part (22) has essentially the same shape as the first tapering part (21). 6. Bristle according to claim 1, characterized in that it has a pointed end (7), which is adjacent to the cylindrical part (1) on the opposite first tapering part (21). 7. The bristles according to claim 1, characterized in that the diameter D _zyl lies in the range from 150 to 170 microns or in the range from 180 to 210 microns. 8. The bristles according to claim 1, consisting of a polyester or polyamide. 9. The bristles of claim 8, consisting of polyethylene terephthalate, polybutylene terephthalate or polyamide-6,6. 10. Toothbrush containing one or more bristles according to any one of claims 1 to 9.

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