JPS6088110A - Monofilament for tooth brush - Google Patents

Abstract

PURPOSE:To provide the titled filament having a specific multi-lobed cross-section with point symmetry and balanced dental cleaning effect and gingival massaging effect, and made of a linear synthetic polymer having a specific flexural recovery. CONSTITUTION:The objective monofilament is made of a linear synthetic polymer having a flexural recovery of >=60%, and has a multi-lobed cross-section having preferably 3-6 lobes and point symmetry, wherein the form of the cross- section is characterized in that (A) the protruded part of each lobe has a tapered form, (B) the maximum space area ratio is <=0.2, (C) the flatness ratio is 1-1.7, (D) the solidity ratio is 0.5-1, and (E) the cross-sectional area is 0.002-0.2mm.<2>. The linear polymer is preferably composed mainly of polybutylene terephthalate having an intrinsic viscosity of 0.8-2.2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-lobed cross-sectional monofilament for toothbrushes that has an excellent tooth cleaning effect and a gum surge effect in a well-balanced manner.

In general, the bristles of toothbrushes need to have a well-balanced effect of cleaning the teeth and pulsating the gums.In order to achieve the above characteristics, the bristles of circular cross-section monofilament, which have been mainly used in the past, have to be thick. difference,
Various studies have been made on the length, flocking method, material and shape of the handle, etc. However, if the thickness of the brush bristles is increased, the stiffness of the brush becomes stronger, which can increase the cleaning effect on the flat surfaces of the teeth and the pine surge effect, but on the other hand, the cleaning effect between the teeth may decrease, and the brush may be damaged by the gums. Become more easily injured. Furthermore, if the thickness of the bristles is made thinner in order to improve the cleaning effect between the teeth, the pine surge effect will be reduced, and problems will arise in terms of the durability of the toothbrush. Therefore, when designing toothbrushes that use monofilament with a circular cross section, various measures have been taken, such as mixing monofilaments of different thicknesses and making the height of the bristles different. The reality is what is required.

On the other hand, with the aim of diversifying the texture and luster of synthetic fibers and imparting stiffness, water permeability, and bulk, the cross-sectional shape of the fibers was made into a multi-lobed cross-section (for example,
Publication No. 20770 and edited by Japan Institute of Textile Science; "Form of Fibers" Breakfast Shoten (1982 T-IJ) are known, and in Publication No. 33512 of 1982, there are several corner parts used as a brush material for car wash cleaning. The use of fibers having protruding thin fins with an acute cross section is further disclosed in Japanese Patent Application Laid-Open No. 56-4347.
Publication No. 1 proposes the use of tapered synthetic fibers with deadly lines in brushes and the like. However, when using such multi-lobed monofilament as the bristles of a toothbrush, there is a concern that it may easily damage the gums.
Moreover, it was considered unsuitable for use in toothbrushes because it was difficult to set appropriate shapes and physical properties.

The present inventors conducted studies aimed at obtaining a high-performance toothbrush bristles that do not damage the gums and have a well-balanced tooth-cleaning effect and gum-surge effect.
By specifying the cross-sectional shape and physical properties, it was discovered that the multi-lobed cross-sectional monofilament exhibits excellent performance as a toothbrush, and the present invention was achieved.

That is, the present invention has the following cross-sectional shape (A) -= (D)
The cross-sectional area is 0.002 to 0.2 and satisfies the characteristics of
The present invention provides a monofilament for a toothbrush made of a linear synthetic polymer, which has a multi-lobed cross-section having substantially point symmetry of zw2 and has a bending recovery rate of 70% or more.

(A) The protruding parts of the multilobes are 3- It has a tapered shape.

(B) Maximum space area ratio is 0.2 or less (C) Oblateness ratio is 1 or more and 1.7 or less (D) Solid ratio is 0.5 or more and less than 1.0 The multi-lobed cross-sectional body as referred to in the present invention is: As shown in FIGS. 1 to 4, the monofilament cross section has substantially point symmetry, and a plurality of protrusions A
and a concave portion B, and the protruding portion A becomes thinner toward the tip. The required number of protrusions may be 3 or more, but if the number is 8 or more, the cleaning effect and pine surge effect will be relatively small in improvement, so a multi-lobed cross-sectional body having 3 to 6 protrusions is particularly preferred. Further, in order to maintain uniformity of the cleaning effect in the direction of the cross section, it is necessary that the cross-sectional shape has substantially point symmetry. The characteristics of point symmetry are defined as: (1) monofilament and the one with the largest area among the spatial parts (C+, Ci, and Cs in Figure 1) surrounded by straight lines circumscribing adjacent protrusions and concave parts; The ratio of the actual cross-sectional area (S) and the sum of the areas of the above-mentioned spatial parts, that is, the maximum spatial area ratio represented by maxAx 4- / (S + ΣAx) and (2
) Among the two parallel lines circumscribing any one or two points of the multilobal cross section, the length of the one with the maximum distance between the straight lines and the one with the minimum distance is the ratio of Lmax x and LMII+) in Figure 6, i.e. It is defined by two characteristics of flatness expressed as Lmax/L=. The range that is substantially point symmetric in the present invention has a maximum space area ratio of 0.2 or less, preferably 0.15 or less, and an aspect ratio of 1 or more and L7 or less, preferably 1 or more and 1.6.
It is as follows.

If the maximum space area ratio or aspect ratio deviates from this value, both the toothbrush's cleaning effect and pine surge effect will not be sufficient.

Furthermore, as an essential condition for the shape of the multi-lobed cross-sectional body, it is necessary that the size of the protrusion be within a specific range. What defines this property is the actual cross-sectional area of the monofilament,
It is defined as the ratio of the area of each space formed by the straight line circumscribing the adjacent protrusion and the four parts to the sum of the actual cross-sectional area of the monofilament, that is, the solidity ratio shown by S/(S + ΣAx), and this value is 0. It is necessary that it is .5 or more and less than 1.0, preferably 0.6 or more and less than 1.0. If the solidity ratio is less than 0.5, the pine surge effect will not be sufficient and the cleaning effect will not be obtained. There is no one with a solidity ratio of 1.0 or more.

The reason why the multi-lobed cross-sectional monofilament according to the present invention has an excellent cleaning effect and pine surge effect is not necessarily clear, but the following may be considered.

(1) The protrusions of the multi-lobed cross-section are narrow, allowing for deep cleaning between teeth.

(2) Toothpaste is retained in the four parts, improving the polishing effect.

(3) Since the number of points where each bristles comes into contact with the teeth and gums increases, the polishing effect and pine surge effect are improved.

(4) It is easy to obtain the strength of the hair, and it has an excellent pine surge effect without damaging the gums.

In order to maintain the durability of the toothbrush and withstand long-term use, the multi-lobed cross-sectional body has a specific shape as described above, and must have a bending recovery rate of 60% or more as specified below.
Preferably, it needs to be 70% or more. In other words, make an intersecting ring with two monofilaments, apply a load of 1/2F per denier for 3 minutes, and then
The bending recovery rate is the value expressed as a percentage of the opening angle of the bending point with respect to the flat angle after cutting at the 0H point and leaving it for 60 minutes.If this value is less than 60%, it will deteriorate in a short period of time and permanent deformation will occur. This is not preferable because the cleaning effect is greatly reduced and the pine surge effect is also reduced, making it unusable as a toothbrush.

In order to obtain a monofilament with a flexural recovery rate of 6096 or more, a polyester containing polybutylene terephthalate as a main component or a polyester having an intrinsic viscosity of 0.8 to 2.2 as measured at 25°C in an orthochlorophenol solution or 98%
The relative viscosity of a solution of Polymer IN dissolved in 100 cc of sulfuric acid was measured at a temperature of 25°C using an Ostwald viscometer. It is preferable to use a polyamide containing at least one type of polyamide as a main component, and monofilaments obtained by melt-spinning, stretching 3 to 7 times, and then heat-treating any of the polymers are preferable.

The thickness of the monofilament for toothbrushes of the present invention is such that its cross-sectional area is 0.002 to 0.2, particularly 0.007 to 1.
A range of m2 is preferred. If the cross-sectional area is smaller than o,oo2gg'', it is too soft for toothbrush bristles, 0.211
If it exceeds 12, it is undesirable because it is too hard and can easily damage the gums.

The present invention will be explained in more detail with reference to Examples below.

The cleaning properties of the toothbrushes were tested using the following method.

Apply black magic ink to an aluminum plate, place a toothbrush so that the tip of the bristles touch it, apply a load of 490 f, and shake it] 75 fins, 180 cpm, and replenish with 5% water slurry of commercially available toothpaste. I rubbed them together and read the number of times it took to remove the marker ink.

8- Hair stiffness, which indicates the pine surge effect, was tested using the following method.

The tips of the toothbrush bristles are pressed against a rubber plate and compressed at a speed of 12 fins/min to read the maximum load.

Examples 1 to 4 and Comparative Example 1 Polybutylene terephthalate with an intrinsic viscosity of 2.0 (bundled P
BT-1500) was melted and extruded into water through Y-shaped, ten-shaped, star-like Homare-shaped and X-shaped nozzles with an IHφ circular shape, a slit length of 0.4 fl, and a width of 0.3 cod, respectively. After cooling and assimilation, it was stretched to a total of 4.6 times in warm water at 60°C in the first stage and 80°C in the second stage, and then adjusted to 180°C and sent to a hot blast oven for 5 seconds at a stretching ratio of 1.0x. Pass through the tube for a long time, and after cooling, wind it up in a straight line with a cross-sectional area of about 0.035n.
A monofilament for toothbrush No. 2 was obtained.

The cross-sectional shapes of the obtained monofilaments were circular and multilobal as shown in FIGS. 1 to 4, respectively, and the bending recovery rates were as shown in Table 1. Next, these monofilaments were grafted onto a toothbrush base material, and the cleaning performance and stiffness of the bristles were measured. The results are also shown in Table 1. As is clear from Table 1, the cleaning effect of the multi-lobed sections of the present invention (Examples 1 to 4) is superior to that of the circular sections (Comparative Example 1), and the effectiveness of 3.4.6 lobed sections is In addition, the hair strength is the same or higher, and the pine surge effect is also excellent.

Examples 5 to 8 and Comparative Example 2.3 Nylon 610 (east nylon M2O) with relative viscosity 2.7
01) and nylon 612 (Dupont's 'Zytel' 151) with a relative viscosity of 2.3 were used to prepare cross-sections of approximately o and o35g with different cross-sectional shapes as in Example 1 and Comparative Example I.
Six types of monofilaments for toothbrushes of ig were obtained.

Table 1 shows the cross-sectional shape and bending recovery rate of the obtained monofilament. Table 1 also shows the results of measuring the cleaning performance and stiffness of the bristles by implanting the bristles onto a toothbrush base material. From this result, it is clear that the 3-lobed and 6-lobed sections are superior in cleaning performance compared to the circular section.

Comparative Examples 4 to 6 Slit length 1.0 n 1 width Q, 3 III Y type, and two slits have length Q, 4 sn, l is l,
Qmm, width is 0.3H, foot length and slit length l, Q
A polybutylene terephthalate monofilament having a cross-sectional area of about 0.035 tz2 was obtained in the same manner as in Example 1 using a Y-shaped die having a width of 0.2 am and a width of 0.2 fins.

Table 1 also shows the measurement results of the cleaning performance and bristles strength of toothbrushes implanted with these monofilaments.

The cross-sectional shapes of the obtained monofilaments are
It had a multilobed shape as shown in Figure 6, and the bending recovery rate was as shown in Table 1. From this result, in Comparative Example 4, the maximum space area ratio was 0.2.
2. Comparative Example 5 had an aspect ratio of 1.81, and Comparative Example 6 had a solid ratio of 047, both of which were out of the appropriate range, and it was clear that the cleaning performance was significantly inferior.

Comparative Example 7.8 Example! A monofilament 11-lament having a cross-sectional area of 0.035 m2 was obtained in the same manner as in Example 1 and 6 except that the heat treatment after stretching was omitted.

The evaluation results of the obtained monofilaments are shown in Table 1, and it is clear that the cleaning properties are poor due to the small bending recovery rates of 57% and 62%.

Example 9, IO Nylon 1'l (Fura:/y,
#RI LSAN' manufactured by ATO) and relative viscosity 2
．． A cross-sectional area of about 0.0351W2 was prepared in the same manner as in Example 1, except that No. 5 nylon 12 (CM5051F manufactured by Toshishiku Co., Ltd.) was used and the heat treatment temperature after stretching was 160°C.
A monofilament for a toothbrush with a trilobal cross section was obtained. As shown in Table 1, these evaluation results showed that the cleaning properties were excellent.

12- -14-

[Brief explanation of drawings]

Figures 1 to 7 are cross-sectional views (approximately 130 times enlarged) of multi-lobed monofilaments; Figures 1 to 4 are examples of the present invention;
Figures 7 to 7 show comparative examples. A~Protrusion B~Four parts C~Space portion Patent application Daito Monofilament Co., Ltd. 1i11 Figure 5

Claims (4)

[Claims] (1) The cross-sectional shape satisfies the following characteristics (A) to medium), is a multi-lobed cross-sectional body with a cross-sectional area of 0.002 to 0.2 mtf, and has substantially point symmetry, and has bending recovery. A monofilament for a toothbrush made of a linear synthetic polymer, characterized in that the ratio is 60% or more. (A) The multilobed protrusion has a shape that tapers toward the tip. (B) The maximum space area ratio is 0.2 or less. (C) The flattening ratio is 1 or more and 1.7 or less. (D) Solidity ratio is 0.5 or more and less than 1.0. (2) The monofilament for a toothbrush according to claim 1, which has a multi-lobed cross section of 3 to 6 lobes. (3) The monofilament for a toothbrush according to claim 1, wherein the linear synthetic polymer is substantially polybutylene terephthalate having an intrinsic viscosity of 068 to 2.2. (4) The linear synthetic polymer is substantially nylon 61O, nylon 612, or nylon 11 with a relative viscosity of 1.5 to 4.5.
The monofilament for a toothbrush according to claim 1, characterized by at least one selected from nylon 12 and nylon 12.