Brush bristles and brushes

Abstract

To provide a novel monofilament excellent in cleaning properties, functional agent retention, and durability during use, and a brush using the same. [Solution] A brush bristle material characterized by comprising a monofilament made of polyester resin containing 0.05% by mass or more and 5% by mass or less of porous silica particles having an average particle diameter of 1 μm or more and 10 μm or less, and having a tapered portion at at least one end.

Description

[Technical Field]

[0001] The present invention relates to brush bristles that have excellent cleaning properties at the tips of the bristles, excellent retention of functional materials made of liquid or powder, and excellent durability, and to brushes using the same. [Background technology]

[0002] Conventionally, a technique for tapering the tip of a synthetic monofilament for use as a brush bristle material has been widely known. However, the tapered portion of the monofilament has a smooth surface, which has the problem of being poor at cleaning plaque and other stains that have adhered to the tooth surface. It also has the problem of being poor at retaining liquids, such as medicines, and powders, such as cosmetics.

[0003] For this reason, techniques for improving the surface of the tapered portion have been disclosed. For example, a cosmetic brush bristle material has been proposed in which inorganic particles are added to the bristles to provide unevenness on the tapered surface (see, for example, Patent Document 1).

[0004] As a method for eliminating fine particles from brush bristle material, a brush bristle material has been proposed in which the sheath component of a core-sheath structure yarn is mixed with hard particles, and the sheath component is removed to make the surface of the core component uneven (see, for example, Patent Document 2).

[0005] Furthermore, polyester fibers have been proposed that use porous silica as fine particles contained in the hair material, and that have improved moisture absorption and desorption properties compared to synthetic resin fibers (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-109990 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-86683 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-18813 Summary of the Invention [Problem to be solved by the invention]

[0007] However, although the cosmetic brush bristle material described in Patent Document 1 has a rough surface due to the inorganic particles, and therefore has a high ability to retain functional agents, the fine particles fall off with repeated use, causing changes in the feel when used and the ability to retain functional agents, resulting in a problem of poor durability.

[0008] The technology described in Patent Document 2 creates irregularities in the resin itself, preventing particles from falling off. However, when the tip is tapered, the irregularities in the tapered part disappear, resulting in insufficient cleaning properties and functional material retention.

[0009] Furthermore, the technology described in Patent Document 3 uses porous silica as the fine particles, but does not improve the cleaning properties or the retention of functional materials, and the intended effect is different.

[0010] The problem to be solved by the present invention is to provide a novel monofilament that is excellent in cleaning properties, functional agent retention, and durability, and a brush using the same. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a brush bristle material that is made of a monofilament made of a polyester resin containing 0.05% by mass to 5% by weight of porous silica particles having an average particle diameter of 1 μm to 10 μm, and that has a tapered portion at at least one end.

[0012] In the present invention, the pore volume of the porous silica particles is 0.4 ml / g or more and 2.0 ml / g or less. the arithmetic mean roughness Ra of the surface of the tapered portion of the monofilament made of polyester resin in a region of 200 μm in the axial direction centered at a position 300 μm from the tip is 1.0 to 3.0 μm; A more preferable condition is that the polyester resin is a mixture of polytrimethylene terephthalate and polybutylene terephthalate in a mass ratio of 95 / 5 to 60 / 40.

[0013] The brush of the present invention is characterized in that any one of the above brush bristles is used as at least a part of the bristles. [Effects of the Invention]

[0014] According to the present invention, it is possible to obtain a novel monofilament that is excellent in cleaning properties, functional agent retention, and durability during use, and a brush using the same. DETAILED DESCRIPTION OF THE INVENTION

[0015] The brush bristle material of the present invention is characterized by comprising a monofilament made of a polyester resin containing 0.05% by mass to 5% by mass of porous silica particles having an average particle diameter of 1 μm to 10 μm, and having a tapered portion at at least one end.

[0016] The average particle size referred to here is a value determined by volume average. By using porous silica as the particles to be added, the porous silica is also dissolved by the caustic soda used during tapering, making it possible to prevent silica from remaining on the surface of the tapered portion.

[0017] First, the porous silica used in the brush bristle material of the present invention must have an average particle size of 1 μm or more and 10 μm or less, and preferably 2 μm or more and 8 μm or less.

[0018] This is because if the average particle size of the porous silica is below the above range, the surface of the tapered portion of the monofilament is not sufficiently modified and remains smooth, resulting in poor cleaning properties and poor retention of functional materials.

[0019] On the other hand, if the thickness exceeds the above range, the monofilament tends to break during production, making production difficult, and the bristles tend to break when used in a toothbrush, which is not preferable.

[0020] The porous silica particles must be present in an amount of 0.05% by mass to 5% by mass relative to the polyester resin. If the amount is less than this range, the tapered surface of the monofilament will remain smooth, resulting in poor cleaning properties and poor retention of functional materials. Conversely, if the amount is more than this range, the bristles will be prone to breakage when used in a toothbrush, which is undesirable.

[0021] Furthermore, the pore volume of the porous silica contained in the brush bristle material of the present invention is preferably 0.4 ml / g or more and 2.0 ml / g or less.

[0022] If the pore volume is below the above range, the silica tends to remain undissolved during tapering, and the silica tends to fall off during use, resulting in poor durability. Silica with a pore volume exceeding the above range is not preferred because its production is difficult.

[0023] Furthermore, the arithmetic mean roughness Ra of the surface of the tapered portion of the monofilament in a region of 200 μm in the axial direction centered at a position 300 μm from the tip is preferably 1.0 to 3.0 μm.

[0024] If the arithmetic mean roughness is below the above range, it is not preferred because the cleaning ability and the ability to retain the functional agent are poor, and if it is above the above range, it is not preferred because the surface becomes rough, not only is the feeling of use poor, but also bristle breakage is likely to occur.

[0025] There are no particular restrictions on the resin that constitutes the brush bristle material of the present invention, as long as it is a polyester resin that dissolves in caustic soda, but a resin that is a mixture of polytrimethylene terephthalate (hereinafter sometimes abbreviated as PTT) and polybutylene terephthalate (hereinafter sometimes abbreviated as PBT), which have excellent durability, in a mass ratio of 95 / 5 to 60 / 40 is preferably used.

[0026] If the PTT content exceeds the above range, durability will be poor, with bristles breaking and the like, and if it is below this range, durability in terms of bristles opening will be poor, which is undesirable.

[0027] Furthermore, the brush bristle material of the present invention can contain various additives depending on the purpose, as long as the effects of the invention are not impaired. Specific examples include particles such as various inorganic particles, various metal particles, and crosslinked polymer particles, as well as known antioxidants, light resistance agents, weather resistance agents, ion exchange agents, color inhibitors, antistatic agents, various colorants, waxes, silicone oils, various surfactants, and various reinforcing fibers.

[0028] Here, the method for producing the brush bristle material of the present invention will be described.

[0029] The method for producing the brush bristle material of the present invention does not require any special method, and known spinning methods can be applied. For example, a thermoplastic resin is melt-extruded using a mixed extruder such as an extruder or a melt-spinning machine such as a pressure melter, and then the extruded resin is cooled and solidified, heat-stretched, and heat-set to form a synthetic resin monofilament, which is then cut to the required length.

[0030] The cross-sectional shape of the brush bristle material of the present invention is not particularly limited, and may be flat, square, crescent, fan-shaped, triangular, polygonal with five or more sides, multi-lobed, dogbone-shaped, cocoon-shaped, or have a hollow portion. It can also be used as one of the components of a composite yarn.

[0031] Furthermore, in order to make the tip of the synthetic resin monofilament tapered, it can be easily formed into a tapered shape by immersing it in caustic soda and dissolving the tip.

[0032] The brush bristles obtained in this way have unevenness at the tip and, furthermore, no particles fall off during use, resulting in little change in feel when used and excellent durability.The brush bristles of the present invention can be used in oral care products such as toothbrushes and interdental brushes, as well as hairbrushes, body brushes, cleaning brushes, cosmetic brushes, etc. [Example]

[0033] The brush bristle material of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0034] The various characteristic values ​​of the brush bristles were measured by the following methods after preparing a toothbrush in which the bristles were implanted in a head having a diameter of 1.5 mm and bristle implantation holes arranged in 8 rows and 4 columns.

[0035] The cleaning properties and durability of the examples were evaluated according to the following methods, with n=4 for each evaluation. [Cleaning evaluation] Nissin artificial plaque was applied to a dental model and allowed to dry for at least 5 minutes. Evaluation was performed by brushing the upper surface of the dental model 100 times with an average brushing pressure of 250g, a stroke of 20mm, and a speed equivalent to 150 rpm. After brushing, the model was photographed under a microscope and the percentage of artificial plaque removed was calculated using image analysis, and cleanability was evaluated according to the following criteria.

[0036] ○: Artificial plaque removal rate (%) is 80.0% or more △: Artificial plaque removal rate (%) is 70.0% or more but less than 80.0% ×: Artificial plaque removal rate (%) is less than 70.0% [Evaluation of durability of hair opening] A 300g load was applied to the toothbrush, and with 37°C warm water dripping onto it, the toothbrush was brushed 20,000 times against a stainless steel corrugated plate with a stroke width of 70mm and a stroke speed of 180mm / sec. After this, the condition of the toothbrush was measured to determine the width of the bristles opening, and the bristles opening rate (%) was calculated using the following formula (1) and evaluated according to the following criteria.

[0037] ○: Hair opening rate (%) is less than 20.0% △: Hair opening rate (%) is 20.0% or more but less than 30.0% ×: Hair opening rate (%) is 30.0% or more Hair opening rate (%) = 100 × (ba) / a (1) Here, a represents the width (mm) of the bristle portion of the toothbrush before the sliding test, and b represents the width (mm) of the bristle portion of the toothbrush after the sliding test. [Evaluation of durability against bristle breakage] The samples that had been subjected to the evaluation of bristle opening durability were visually observed for the presence or absence of breakage at the bristle roots, and were evaluated according to the following criteria.

[0038] ○: No hair breakage was observed △: Some brushes had broken bristles ×: Broken bristles were observed on all brushes [Evaluation of cleaning performance retention] The cleaning performance was evaluated again using the samples that had been subjected to the bristle opening durability evaluation. The artificial plaque removal rate (%) was calculated, and the cleaning performance retention rate (%) was calculated using the following formula (2), and the cleaning performance retention was evaluated according to the following criteria.

[0039] 〇: Cleaning performance retention rate (%) is 90.0% or more △: Cleaning performance retention rate (%) is 80.0% or more but less than 90.0% ×: Cleaning performance retention rate (%) is less than 80.0% Cleaning performance retention rate (%)=100-100×(cd) / c...(2) Here, c represents the percentage of artificial plaque removed by the toothbrush before the evaluation of bristles' durability to opening, and d represents the percentage of artificial plaque removed by the toothbrush after the evaluation of bristles' durability to opening. [Example 1] The raw material was a 90:10 blend of PTT pellets (SORONA, manufactured by Conovation Biomaterials) and PBT pellets (Trecon 1200S, manufactured by Toray Industries, Inc.), mixed with 0.2% porous silica (Silisia 430, manufactured by Fuji Silysia Chemical Co., Ltd.) with an average particle size of 4.1 μm and a pore volume of 1.25 ml / g. The mixture was then fed into a melt spinning machine, and the synthetic resin melt was extruded from the nozzle.

[0040] Subsequently, the extruded synthetic resin melt was cooled and solidified in a cooling bath, and then drawn and heat-set to obtain a monofilament having a diameter of 0.18 mm.

[0041] The obtained monofilaments were bundled in a straight bundle with a bundle diameter of 45 mm, packaged, and then cut to a length of 29 mm. Next, both ends of the cut bundle were immersed in an alkaline solution to form tapered portions, washed with water, and then dried to obtain tapered brush bristle materials.

[0042] The cleaning ability and durability of the obtained brush bristles are shown in Table 1. [Examples 2 to 5] Brush bristle materials were obtained in the same manner as in Example 1, except that the particle size, amount added, and pore volume of the porous silica added to the resin were as shown in Table 1. [Examples 6 to 8] Brush bristle materials were obtained in the same manner as in Example 1, except that the resins used were as shown in Table 1. [Comparative Examples 1 and 2] Brush bristle materials were obtained in the same manner as in Example 1, except that the inorganic particles added to the resin were changed as shown in Table 1. Comparative Example 3 A brush bristle material was obtained in the same manner as in Example 1, except that no inorganic particles were added to the resin.

[0043] Table 1 shows the evaluation results of the brush bristles obtained in the above Examples and Comparative Examples.

[0044] [Table 1]

[0045] As is clear from the results shown in Table 1, the brush bristles of the present invention (Examples 1 to 8) have unevenness at the tip, which makes the tip of the bristles easier to clean, and furthermore, no particles fall off during use, which means that there is little change in performance.

[0046] In contrast, monofilaments that do not satisfy the conditions of the present invention (Comparative Examples 1 to 3) were unable to fully exhibit the effects of the present invention. For example, the brush bristles to which alumina that is not soluble in alkali was added (Comparative Example 1) had the alumina particles fall off during use, and were unable to maintain cleaning performance. The brush bristles to which titanium oxide with a small average particle size was added (Comparative Example 2) and the brush bristles to which no inorganic particles were added (Comparative Example 3) had poor unevenness at the tip and were inferior in cleaning performance. [Industrial Applicability]

[0047] The brush bristles of the present invention have unevenness at the tip and do not lose particles during use, resulting in brush bristles that are less sensitive to use and have excellent durability.The brush bristles of the present invention can be used in oral care products such as toothbrushes and interdental brushes, as well as hairbrushes, body brushes, cleaning brushes, cosmetic brushes, etc.

Claims

1. A brush bristle material characterized by comprising a monofilament made of a polyester resin containing 0.05% by mass or more and 5% by mass or less of porous silica particles having an average particle diameter of 1 μm or more and 10 μm or less, and having a tapered portion at at least one end.

2. 2. The brush bristle material according to claim 1, wherein the pore volume of the porous silica particles is 0.4 ml / g or more and 2.0 ml / g or less.

3. The brush bristle material according to claim 1 or 2, characterized in that the arithmetic mean roughness Ra of the surface of the tapered portion of the monofilament made of polyester resin in a region of 200 μm in the axial direction, centered at a position 300 μm from the tip, is 1.0 to 3.0 μm.

4. The brush bristle material according to any one of claims 1 to 3, characterized in that the polyester-based resin is a mixture of polytrimethylene terephthalate and polybutylene terephthalate in a mass ratio of 95 / 5 to 60 / 40.

5. A brush characterized in that the brush bristles according to any one of claims 1 to 4 are used as at least a part of the bristles.

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