Cosmetic filament, cosmetic brush bristle material using same filament, and cosmetic brush using same bristle material
09949560 ยท 2018-04-24
Assignee
Inventors
Cpc classification
A46D1/0207
HUMAN NECESSITIES
Y10T428/2927
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
Abstract
A filament for cosmetic brush is constituted by a polyester resin filament having many projections over its entire surface, wherein the polyester resin is polytrimethylene terephthalate and/or polybutylene terephthalate, the polyester resin contains glass particles of 1 to 2 m in average particle size by 0.3 to 1.0 percent by weight as the inorganic particles, the thermal conductivity of the glass particle is in a range of 5 to 7 times that of the resin, and the projections are formed over the entire surface of the cosmetic filament by the glass particles covered with the resin.
Claims
1. A cosmetic brush bristle material having a body and tapered tip formed by alkali treatment on one end of a cosmetic filament constituted by polyester resin containing inorganic particles, wherein: the polyester resin is polytrimethylene terephthalate and/or polybutylene terephthalate; the polyester resin contains silver glass particles of 1 to 2 m in average particle size by 0.4 to 0.5 percent by weight as the inorganic particles; a thermal conductivity of the silver glass particles is in a range of 5 to 7 times that of the resin; and the cosmetic filament has three regions along an axial direction of the cosmetic filament, the three regions being: a first region where projections are formed over an entire surface of the first region of the filament by the silver glass particles covered with the resin, a second region corresponding to the body which is not a part of the tapered tip, closer to the tapered tip than is the first region, and contiguous with the first region, where projections are formed by the silver glass particles which manifest over the entire surface of the second region of the filament as a result of melting and removing the resin covering the projections of the glass particles, wherein the projections formed over the entire surface of the body have a height of 1.1 to 1.3 m, wherein a distribution density of projections on the body of the cosmetic brush bristle material is in a range of 20 to 65 projections per 50 m.sup.2, and a third region corresponding to the tapered tip contiguous with the second region and gradually tapered toward an end of the tapered tip, where projections are formed by the silver glass particles which manifest over the entire surface of the third region of the filament as a result of melting and removing the resin covering the projections of the glass particles, wherein a diameter of the tapered tip is in a range of 10 to 25 m.
2. A cosmetic brush bristle material according to claim 1, wherein the thermal conductivity of the silver glass particle is 1.38 to 1.50 W/mK.
3. A cosmetic brush bristle material according to claim 1, wherein a fineness of the cosmetic filament is 2 to 4 mils.
4. A cosmetic brush bristle material according to claim 1, wherein a bacteriostatic activity of the cosmetic brush bristle material whose glass particles are made of silver glass in a range of 4 to 6.
5. A cosmetic brush that uses a cosmetic brush bristle material having a body and tapered tip formed by alkali treatment on one end of a cosmetic filament constituted by polyester resin containing inorganic particles, wherein: the polyester resin is polytrimethylene terephthalate and/or polybutylene terephthalate; the polyester resin contains silver glass particles of 1 to 2 m in a average particle size by 0.4 to 0.5 percent by weight as the inorganic particles; a thermal conductivity of the silver glass particle is in a range of 5 to 7 times that of the resin; the cosmetic filament has three regions along an axial direction of the cosmetic filament, the three regions being: a first region where projections are formed over an entire surface of the first region of the filament by the silver glass particles covered with the resin, a second region corresponding to the body which is not a part of the tapered tip, closer to the tapered tip than is the first region, and contiguous with the first region, where projections are formed by the silver glass particles which manifest over the entire surface of the second region of the filament as a result of melting and removing the resin covering the projections of the glass particles, wherein the projections formed over the entire surface of the body have a height of 1.1 to 1.3 m, wherein a distribution density of projections on the body of the cosmetic brush bristle material is in a range of 20 to 65 projections per 50 m.sup.2, and a third region corresponding to the tapered tip contiguous with the second region and gradually tapered toward an end of the tapered tip, where projections are formed by the silver glass particles which manifest over the entire surface of the third region of the filament as a result of melting and removing the resin covering the projections of the glass particles, wherein a diameter of the tapered tip is in a range of 10 to 25 m; and the cosmetic brush bristle material used for the brush in which the first and second regions covering the body and the third region covering the tapered tip are used to apply cosmetic materials is applied to a foundation brush, powder brush, eye shadow brush, lip brush or shadow brush.
6. A cosmetic brush according to claim 5, wherein the thermal conductivity of the silver glass particles is 1.38 to 1.5 W/mK.
7. A cosmetic brush according to claim 5, wherein a fineness of the cosmetic filament is 2 to 4 mils.
8. A cosmetic brush according to claim 5, wherein a bacteriostatic activity of the cosmetic brush bristle material whose glass particles are made of silver glass is in a range of 4 to 6.
9. A cosmetic brush bristle material according to claim 1, wherein the polyester resin consists of a blend of polytrimethylene terephthalate and polybutylene terephthalate.
10. A cosmetic brush bristle material according to claim 5, wherein the polyester resin consists of a blend of polytrimethylene terephthalate and polybutylene terephthalate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
DESCRIPTION OF THE SYMBOLS
(8) 1 Extrusion machine 2 Motor 3 Gear reducer 4 Screw 5 Heater/blower 6 Screw thread 7 Breaker plate 8 Nozzle die 9 First hopper 9 Pellets 10 Second hopper 10 E glass powder
MODE FOR CARRYING OUT THE INVENTION
(9) (Thermoplastic Resin)
(10) Polyester resins that can be used for the cosmetic brush bristle material include polytrimethylene terephthalate (hereinafter referred to as PTT) and polybutylene terephthalate (hereinafter referred to as PBT) from the viewpoints of physical properties such as flexibility, elastic recovery and water resistance. PTT may be used on its own, PTT and PBT may be blended, or PBT may be used on its own.
(11) (Glass Particles)
(12) Glass particles that can be contained in the resin used for the cosmetic brush bristle material include those made of E glass, silver glass, and silica glass. The thermal conductivity of E glass is 1.50 W/mK, while that of silver glass varies around 1.40 W/mK depending on the blended material(s). The silver glass used in the examples has a thermal conductivity of 1.40 W/mK. Also, the thermal conductivity of quartz glass is 1.38 W/mK, but it varies from 1.38 W/mK depending on the blended material(s).
(13) Glass particles are blended with the polyester resin by 0.3 to 1.0 percent by weight. If the blending ratio is 0.3 percent by weight or less, the heights of glass particles projecting over the entire surface of the tapered part of the filament become 1.0 m or less, which is not preferable. If the blending ratio is 1.0 percent by weight or more, on the other hand, the filament may break during the drawing process. As a result, preferably glass particles are blended with the resin at a blending ratio in a range of 0.3 to 1.0 percent by weight.
(14) Note that manufacturing methods for E glass, silica glass, and silver glass are well known and therefore not explained.
(15) (How to Manufacture Pellets Containing Glass Particles)
(16) First, how to manufacture pellets constituted by the resin containing glass particles, as the material for the cosmetic brush bristle material proposed by the present invention, is explained.
(17) The pellets are manufactured using the conventional extrusion machine shown in
(18) Reference numeral 1 represents an extrusion machine, 2 represents a motor, 3 represents a gear reducer, 4 represents a screw, 5 represents a heater/blower, 6 represents a screw thread, 7 represents a breaker plate, 8 represents a nozzle die, 9 represents a first hopper, 9 represents pellets, 10 represents a second hopper, and 10 represents E glass powder.
(19) The extrusion machine 1 has two hoppers into which to introduce the supplied materials, or specifically the resin pellets 9 and E glass powder 10. The hoppers of the extrusion machine 1 shown in
(20) An appropriate weight of pellets 9 to be supplied is measured according to the specified blending ratio of the resin and glass particles and introduced into the first hopper 9, after which the pellets 9 are kneaded and transferred by the screw 4 and melted by the heater, at which position, or specifically at the position where the second hopper is placed, the weighed glass particles 10 to be supplied are introduced into the second hopper. The molten resin is kneaded with the glass particles 10 introduced in it and the mixture is extruded to form a molding containing glass particles 10, which is then cut to obtain pellets containing glass particles 10. The temperature of the heater is determined according to the melting point of the resin used.
(21) It should be noted that the extrusion machine in
(22) (How to Manufacture Cosmetic Brush Bristle Material)
(23) Next, how to manufacture the cosmetic brush bristle material proposed by the present invention is explained.
(24) The filament of the cosmetic brush bristle material is manufactured by melting and spinning pellets containing glass particles. The pellets containing glass particles are dried and introduced to a spinning machine where they are melted, kneaded, extruded, and spun into a yarn from a spinning outlet, after which the yarn is drawn to 4 to 5 times longer through three stages of heating and drawing to manufacture a 3-mill filament. This filament has projections formed over its entire surface by the glass particles covered with polyester resin. Then, multiple filaments thus produced are bundled into a cylinder shape and cut to a specified length, after which one end of the cut filament bundle is alkali-treated with an aqueous sodium hydroxide solution, followed by water washing and drying.
(25) One end of the filament is soaked in an alkali solution to hydrolyze the resin and thereby reduce weight, in order to form a region on this end which is tapered toward the tip and where projections by the glass particles manifest, and this region is referred to as the tapered tip. The aqueous sodium hydroxide solution is siphoned to the cylindrical filament bundle by means of the capillary effect and the resin covering the projections of the glass particles is melted and removed, in order to form a region where the glass particles manifest over the entire surface of the body of the filament, and this region is referred to as the body. Accordingly, the cosmetic brush bristle material proposed by the present invention has a region where projections are formed by the glass particles covered with the resin over the entire surface of the cosmetic filament, and also has regions covering the body and tapered tip, which are contiguous with the above region, where projections are formed by the glass particles over the entire surface.
(26) And, the cosmetic brush proposed by the present invention is used to apply foundation and other cosmetic materials using the aforementioned regions having projections of the glass particles (body and tapered tip).
EXAMPLES
(27) PTT (SORONA J2240 Semi-Dull by DuPont) was introduced to the first hopper of the extrusion machine and melted at 270 C., after which glass particles (of 1 to 2 m in average particle size) were introduced, while being weighed, into the molten PTT from the second hopper, and the screw for which a sufficient agitation and kneading zone had been set was used to extrude and thereby manufacture pellets containing glass particles.
(28) The pellets were dried at 110 C. and then introduced to a spinning machine where the pellets were melted at 270 C., kneaded at 250 C., extruded, and spun into a yarn from the spinning outlet, after which the yarn was drawn to 4 to 5 times longer through three stages of heating and drawing, to manufacture a 3-mill filament. Multiple filaments thus produced were bundled into a cylinder shape of 5 cm in diameter and cut to 6 cm in length. One end of the cut filament bundle was immersed in a 12 wt % aqueous sodium hydroxide solution at 120 C., and the non-immersed part of the immersed filament bundle was gradually raised over time, with the soak time adjusted over a range up to 120 minutes so that the tip of the filament bundle was hydrolyzed to a thickness of 10 to 25 m, in order to form the tapered tip. The bundled filaments on the upper side of the soaked part of the filament bundle siphoned the aqueous sodium hydroxide solution by means of the capillary effect, after which the resin covering the projections formed by the glass particles on the filament surface was melted and removed to form the body. The width of this body can be changed as desired by adjusting the level of tightness of the filament bundle. Next, the obtained filament bundle was water-washed and dried to obtain a cosmetic brush bristle material.
(29) When the tip of the 3-mill (76-m) filament is tapered to 10 to 25 m by means of alkali treatment, non-uniformly blended glass particles may cause the filament to break at a part where glass particles are not blended uniformly, and accordingly it is essential to knead the ingredients sufficiently at the time of blending.
Examples 1 to 8
PTT
(30) The aforementioned manufacturing method was used to manufacture pellets containing glass particles at different glass particle contents and then melt and spin the pellets into a yarn, to manufacture the cosmetic brush bristle materials in Examples 1 to 8 below.
(31) To be specific, filaments made of PTT blended with E glass particles by 0.3 percent by weight (Example 1), 0.4 percent by weight (Example 2), 0.5 percent by weight (Example 3) and 1.0 percent by weight (Example 4), respectively, were drawn to 4 to 5 times longer under the aforementioned conditions to manufacture filaments of 3 mills in fineness. Also, filaments blended with silver glass particles by 0.3 percent by weight (Example 5), 0.4 percent by weight (Example 6), 0.5 percent by weight (Example 7) and 1.0 percent by weight (Example 8), respectively, were drawn to 4 to 5 times longer under the aforementioned conditions to manufacture filaments of 3 mills in fineness. These filaments were each given the aforementioned alkali treatment to form the body and tapered tip.
Comparative Example 1
(32) Comparative Example 1 represents a PTT filament not containing glass particles, which was given the aforementioned alkali treatment to form the body and tapered tip.
Examples 9 to 12
PBT
(33) PBT (TORAYCOM 140106 by Toray) was introduced to the first hopper of the extrusion machine and melted at 270 C., after which glass particles (of 1 to 2 m in average particle size) were introduced, while being weighed, into the molten PBT from the second hopper, and the screw for which a sufficient agitation and kneading zone had been set was used to extrude and thereby manufacture pellets containing glass particles.
(34) Each filament and its body and tapered tip was manufactured according to the same method used in Examples 1 to 8.
(35) The aforementioned manufacturing method was used to manufacture pellets containing glass particles at different glass particle contents and then melt and spin the pellets into a yarn, to manufacture the cosmetic brush bristle materials in Examples 9 to 12 below.
(36) To be specific, filaments made of PBT blended with silver glass particles by 0.3 percent by weight (Example 9), 0.4 percent by weight (Example 10), 0.5 percent by weight (Example 11) and 1.0 percent by weight (Example 12), respectively, were drawn to 4 to 5 times longer under the aforementioned conditions to manufacture filaments of 3 mills in fineness. These filaments were each given the aforementioned alkali treatment to form tapered tip.
Comparative Example 3
(37) Comparative Example 3 shows a PBT filament not containing glass particles, which was given the aforementioned alkali treatment to form the body and tapered tip.
(38) Next, 1000 photographs capturing the surface of a horse hair and surface of each filament of the above cosmetic brush bristle material, all taken by a laser microscope (VK-Analyzer VK-8710 by Keyence), are shown in
(39) The photograph of the surface of an auxiliary horse hair in
(40) The photograph of the surface of the body of a filament constituted by PTT containing silver glass particles by 1 percent by weight, in
(41) The photograph of the surface of the alkali-treated body of a filament constituted by PTT containing silver glass particles by 1 percent by weight, in
(42) The photograph of the surface of the body of a filament constituted by PTT containing silver glass particles by 0.5 percent by weight, in
(43) The photograph of the surface of the alkali-treated body of a filament constituted by PTT containing silver glass particles by 0.5 percent by weight, in
(44) The photograph of the surface of the alkali-treated tapered tip shown on the left side of
(45) The photographs in
(46) Additionally, the body surface of each of the cosmetic brush bristle materials in Examples 1 to 4 (PTT containing E glass), Examples 5 to 8 (PTT containing silver glass) and Examples 9 to 12 (PBT containing silver glass) was observed with a laser microscope (VK-Analyzer VK-8710 by Keyence) to measure the height and distribution of surface projections and thickness of the tapered tip. Table 1 lists the aforementioned heights, distributions and thicknesses of the cosmetic brush bristle materials containing E glass particles (PTT), Table 2 lists the aforementioned heights, distributions and thicknesses of the cosmetic brush bristle materials containing silver glass particles (PTT), and Table 3 lists the aforementioned heights, distributions and thicknesses of the cosmetic brush bristle materials containing silver glass particles (PBT).
(47) TABLE-US-00001 TABLE 1 Comparative Example Example Example Example Comparative Example 1 1 2 3 4 Example 2 Content of E glass 0.0 0.3 0.4 0.5 1.0 Horse hair (% by weight) Height of projections (m) 1.1 1.3 1.3 1.5 2.6 Distribution of projections 26 32 39 65 28 (number of projections per 50 m.sup.2) Thickness of tip (m) 10~20 10~22 12~23 12~23 14~25 10~30 Abnormal thickness (m (%))
(48) According to Table 1, the height of projections in Examples 1 to 4 (PTT) are 1.1 to 1.5 m, while the height of projections on the horse hair is 2.6 m, meaning that the height of projections in Examples 1 to 4 are approx. one-half that on the horse hair, respectively. Table 1 also shows that the distributions of projections in Examples 1 to 4 are 26 to 65 projections per 50 m.sup.2, while the distribution of projections on the horse hair is 28 projections per 50 m.sup.2, where, specifically, the distributions of projections in Examples 1 and 2 are similar to the distribution of projections on the horse hair, and in Examples 3 and 4, the distribution of projections on the PTT hair increases as the content of E glass increases.
(49) Furthermore, Table 1 shows that the thickness of the tips in Examples 1 to 4 (PTT) are 10 to 25 m, while the thickness of the tip of the horse hair is 10 to 30 m, meaning that the thickness of the tips in Examples 1 to 4 (PTT) is similar to the thickness of the tip of the horse hair.
(50) TABLE-US-00002 TABLE 2 Comparative Example Example Example Example Comparative Example 1 5 6 7 8 Example 2 Content of silver glass 0.0 0.3 0.4 0.5 1.0 Horse hair (% by weight) Height of projections (m) 1.1 1.2 1.3 1.6 2.6 Distribution of projections 21 27 33 64 28 (number of projections per 50 m.sup.2) Thickness of tip (m) 10~20 10~22 13~23 13~23 15~25 10~30 Abnormal thickness (m (%)) 45 (15%) Bacteriostatic activity 4.2 4.5 4.7 5.6
(51) It is clear from Table 2 that, because the height and distribution of projections and thickness of tapered parts in Examples 5 to 8 (PTT) are roughly the same, the cosmetic brush bristle materials containing E glass particles and silver glass particles have roughly the same height, distribution, and thickness shape.
(52) However, Example 8 where the aforementioned content is 1.0 percent by weight had a 15% probability of the aforementioned tip having a thickness of 45 m. This thickness of the tip is at least twice the normal thickness and thus abnormal. Because the fineness of the filament is 3 mills, its diameter is 76 m and therefore the above thickness of 45 m of the tip formed by alkali treatment is abnormal, and any cosmetic brush whose filaments include those of such thickness has a serious drawback as the thick bristles will irritate the skin.
(53) Such abnormal thickness occurs in a region where glass particles are not contained uniformly, which in turn results from applying alkali treatment when glass particles are not uniformly contained during the course of screw-kneading of the material after glass particles have been introduced from the second hopper. Accordingly, the aforementioned incidence of abnormal thickness will drop if consideration is given to the kneading conditions of glass particles to achieve uniform distribution of glass particles.
(54) The bacteriostatic activities in Table 2 represent the values obtained from an antibacterial test of Staphylococcus aureus based on the standard of JIS L 1902-1998 (ISO 20743).
(55) According to the test results, the bacteriostatic activities measured on Staphylococcus aureus are in a range of 4 to 6, indicating excellent antibacterial property. The aforementioned standard specifies that a bacteriostatic activity of 2.2 or greater represents antibacterial/deodorizing performance beyond the standard, and the aforementioned bacteriostatic activity range of 4 to 6 is associated with much higher performance.
(56) One problem the users of cosmetic brushes want to see solved as soon as possible is that when the brush contacts the skin, resident bacteria on the skin and aquatic bacteria attach to the brush and the attached bacteria grow on the brush to give off unpleasant smell. Such smell is no longer recognized if 99% of the bacteria are killed. The state where 99% of the bacteria are killed represents a bacteriostatic activity of 2.2. The cosmetic brush bristle materials in Examples 5 to 8 have a bacteriostatic activity ranging from 4 to 6, indicating that the bacteria can be killed more quickly than when the bacteriostatic activity is 2.2 and consequently production of smell can be prevented early. The cosmetic brush bristle materials in Examples 5 to 8 have silver glass projections of 1.0 to 1.5 m present over the entire surface at their tip, at a distribution density of 21 to 64 projections per 50 m.sup.2, which translates to excellent antibacterial property and deodorizing property against resident bacteria in the skin and aquatic bacteria.
(57) TABLE-US-00003 TABLE 3 Comparative Example Example Example Example Comparative Example 3 9 10 11 12 Example 2 Content of silver glass 0.0 0.3 0.4 0.5 1.0 Horse hair (% by weight) Height of projections (m) 1.1 1.1 1.2 1.4 2.6 Distribution of projections 24 30 35 63 28 (number of projections per 50 m.sup.2) Thickness of tip (m) 10~20 10~22 12~23 12~23 14~25 10~30 Abnormal thickness (m (%)) 40 (2%) Bacteriostatic activity 4.0 4.5 4.6 5.5
(58) Examples 9 to 12 represent cosmetic brush bristle materials constituted by PBT containing silver glass by 0.3, 0.4, 0.5 and 1.0 percent by weight, respectively.
(59) Since the height and distribution of projections and thickness of tips in Examples 9 to 12 (PBT) as shown in Table 3 are roughly the same as those in Examples 5 to 8 (PTT), it is suggested that both the cosmetic brush bristle materials constituted by PTT containing silver glass particles and cosmetic brush bristle materials constituted by PBT containing silver glass particles have roughly the same height, distribution and thickness shape.
(60) It is clear from the foregoing that, regardless of whether their polyester resin is PTT or PBT, cosmetic brush bristle materials constituted by PTT or PBT containing glass particles have roughly the same height and distribution of projections and thickness at the tip.
(61) Moreover, since the cosmetic brush bristle materials in Examples 9 to 12 have a bacteriostatic activity ranging from 4 to 6, the bacteria can be killed more quickly than when the bacteriostatic activity is 2.2 and consequently production of smell can be prevented early.
(62) TABLE-US-00004 TABLE 4 Comparative Example Example Example Example Comparative Example 4 13 14 15 16 Example 2 Content of silver glass 0.0 0.3 0.4 0.5 1.0 Horse hair (% by weight) Height of projections (m) 1.1 1.1 1.3 1.5 2.6 Distribution of projections 25 32 37 65 28 (number of projections per 50 m.sup.2) Thickness of tip (m) 10~20 10~22 12~23 12~23 14~25 10~30 Abnormal thickness (m (%)) 40 (2%) Bacteriostatic activity 4.0 4.4 4.7 5.5
(63) Examples 13 to 16 represent cosmetic brush bristle materials constituted by a mixed resin of 60 percent by weight of PTT and 40 percent by weight of PBT, containing silver glass by 0.3, 0.4, 0.5 and 1.0 percent by weight, respectively.
(64) Since the height and distribution of projections and thickness of tips in Examples 13 to 16 (mixed resin of PTT and PBT) as shown in Table 4 are roughly the same as those in Examples 1 to 8 (PTT) and Examples 9 to 12 (PBT), it is suggested that both the cosmetic brush bristle materials constituted by PTT or PBT containing silver glass and cosmetic brush bristle materials constituted by PTT and PBT containing silver glass have roughly the same height, distribution and thickness shape. It is clear from the foregoing that, regardless of whether their polyester resin is PTT or PBT or a mixture thereof, cosmetic brush bristle materials containing glass particles have roughly the same height and distribution of projections and thickness at the tip.
(65) Moreover, since the cosmetic brush bristle materials in Examples 13 to 16 have a bacteriostatic activity ranging from 4 to 6, the bacteria can be killed more quickly than when the bacteriostatic activity is 2.2 and consequently production of smell can be prevented early.
(66) (Use Test Results)
(67) The results of use tests conducted by five subjects on liquid foundation brushes and powder brushes using the bristle materials blended with silver glass in Examples 5 to 8 (PTT) and hair in Comparative Examples 1 and 2, were evaluated on a scale of 1 to 5. The evaluation results of liquid foundation brushes are shown in Table 5, while the evaluation results of powder brushes are shown in Table 6.
(68) Evaluation was made on a scale of 1 to 5, where 5 represents Very good, 4 represents Good, 3 represents Average, 2 represents Bad and 1 represents Very bad.
(69) Similarly, Table 7 lists the evaluation results of use tests conducted by five subjects on powder brushes using silver-glass blended materials in Examples 9 to 12 (PBT).
(70) TABLE-US-00005 TABLE 5 Comparative Example Example Example Example Comparative Example 1 5 6 7 8 Example 2 Content of silver glass 0.0 0.3 0.4 0.5 1.0 Horse hair (% by weight) Loading property 3 4 4 4 5 5 Transfer property 3 4 4 5 5 5 Feeling during use 3 5 5 5 2-5 5
(71) TABLE-US-00006 TABLE 6 Comparative Example Example Example Example Comparative Example 1 5 6 7 8 Example 2 Content of silver glass 0.0 0.3 0.4 0.5 1.0 Horse hair (% by weight) Loading property 3 4 4 4 5 5 Transfer property 3 4 4 5 5 5 Feeling during use 3 5 5 5 2-5 5
(72) TABLE-US-00007 TABLE 7 Comparative Example Example Example Example Comparative Example 3 9 10 11 12 Example 2 Content of silver glass 0.0 0.3 0.4 0.5 1.0 Horse hair (% by weight) Loading property 3 4 4 4 5 5 Transfer property 3 4 4 5 5 5 Feeling of use 3 4 4 4 2-4 5
(73) Compared to the PTT100% brush in Comparative Example 1 or PBT100% brush in Comparative Example 3, both the liquid and powder brushes in the Examples present clearly better loading property and transfer property with respect to cosmetic materials, and offer excellent functionality and touch when used.
(74) The poor touch of the brushes using materials blended with 1.0 percent by weight of silver glass is due to some of the filaments being broken at the tapered tip as a result of alkali treatment and consequently having an abnormal thickness at the tip, which indicates that the blending ratio of glass particles is limited to 1.0 percent by weight even with increased kneading when glass particles are blended.
(75) (Action Mechanism of Projection Forming)
(76) Here, the action mechanism of how a filament produced by melting and spinning pellets containing glass particles into a yarn and then drawing the yarn by 4 to 5 times has projections formed over its entire surface by glass particles covered with polyester resin, and how projections are formed on the surface of the tip when this filament is alkali-treated, is examined.
(77) While the thermal conductivities of glass particles (silica glass, silver glass, and E glass) are 1.38 to 1.50 W/mK, the thermal conductivity of polyester resin (PTT or PBT) is 5.1 to 5.6 times lower at 0.27 W/mK, which means that 5 to 7 times more heat conducts through glass particles than through polyester resin.
(78) Incidentally, it was mentioned earlier that concaves are formed on the surface of the cosmetic brush bristle material containing inorganic powder (silver zeolite) as described in Patent Literature 1. While the thermal conductivity of PBT constituting this brush bristle material is 0.27 W/mK, the thermal conductivity of silver zeolite is 0.58 W/mK, representing only a small difference between the two.
(79) In the drawing process where the resin containing glass particles that has been extruded from the spinning outlet is drawn to 4 to 5 times longer through three stages of heating and drawing, the glass particles present on the surface of this resin are heated at a thermal conductivity around five times the thermal conductivity of the resin, and consequently the resin around the glass particles is heated and softens more quickly than the rest of the resin. This quickly heated and softened resin is drawn first and the glass particles are lifted to form projections. Although the surface of these projections is covered with resin, the resin is subsequently removed by alkali treatment and the height of projections becomes more prominent as a result. It is important that the content of glass particles is in a range of 0.3 to 1.0 percent by weight. If the content of glass particles is 0.3 percent by weight or less, the height of projections becomes 1.0 m or less, which is not desirable. If the content of glass particles is 1.0 percent by weight or more, on the other hand, some of the filaments will break along the tapered tip as a result of alkali treatment and consequently have an abnormal thickness at the tip, which is not desirable as it leads to a poor feeling during use of the cosmetic brush.
(80) On the other hand, the cosmetic brush bristle material containing silver zeolite as described in Patent Literature 1 is such that, as a filament is spun and heated/extended in the drawing process where the filament is drawn to 4 to 5 times longer through three stages of heating and drawing, the molecular chain of the PBT fiber is oriented in the axial direction of the fiber and the cross-section area of the fiber decreases as a result. This is probably explained by the application of tension in the axial direction of the fiber in this drawing process, and consequent action of contracting force toward the center of the fiber section, because, as the thermal conductivity of silver zeolite is not very different from that of PBT, this contracting force causes silver zeolite to sink and allows concaves to be formed on the filament surface.
(81) (Cosmetic Brushes in Examples and Horse-hair Cosmetic Brush)
(82) The cosmetic brush bristle materials in the Examples have the same shape as horse hair in that many projections are formed by glass particles on the surface. Also from the measured height and distribution of projections and thickness of tips in Tables 1 to 4, these projections have a height of approx. one-half the height of projections on horse hair, as well as a distribution of projections similar to or greater than the distribution of projections on horse hair, and the thickness of tips are similar to the thickness of tip of the horse hair. Although the bristle materials in the Examples have a height of projections corresponding to approx. one-half the height of projections on horse hair, their distribution of projections and thickness of tips are similar. Additionally, the results in Tables 5 to 7 indicate that the liquid foundation brushes and powder brushes that represent cosmetic brushes using these bristle materials have loading property and transfer property with respect to cosmetic materials and feeling of use very similar to what is expected from horse hair, and therefore they can be used as substitutes for horse-hair cosmetic brushes. Furthermore, the cosmetic brushes containing silver glass particles have a bacteriostatic activity ranging from 4 to 6 because their projections are formed by silver glass, and consequently demonstrate excellent antibacterial property and deodorizing property.