Brush tip unit, method for manufacturing a brush tip unit, and liquid application tool using a brush tip unit

Abstract

The present invention provides a liquid applicator that can stably coat multiple lines at once, allows for easy control of the coating lines, is less prone to liquid dispensing failures, and is easy to assemble. [Solution] A brush tip unit 1 is provided, comprising a single brush tip 3 made of a tapered monofilament at its tip, and a mouthpiece 2 provided to cover the outer circumference of the tip portion of the brush tip, excluding the tip end, wherein when the brush tip is assembled to the mouthpiece and immersed in a coating liquid, the tip of the brush tip branches into multiple bundles of bristles with capillary action.

Description

【Technical Field】 【0001】 The present invention relates to a nib unit used in liquid applicators such as cosmetic tools and writing implements, a method for manufacturing the nib unit, and a liquid applicator using the nib unit. In particular, it relates to a liquid applicator capable of drawing a plurality of lines at once. 【Background Art】 【0002】 Liquid applicators include types that relay liquid from the rear end portion to the front end portion of the nib, types that immerse the liquid in the front end portion of the nib, and the like. Such types of liquid applicators have been widely popular as essential for cosmetic tools and writing implements since they were first marketed until now. Note that porous materials are used for the nibs of liquid applicators of the type that relays liquid, and types such as those that adhere an aggregate of synthetic fibers with resin and those that converge monofilaments with tapered tips are known. 【0003】 Patent Document 1 discloses a liquid applicator that supplies liquid with a relay core to a nib in which monofilaments with tapered tips are converged. However, since there is only one tip portion of the nib, there is a problem that a plurality of lines cannot be drawn at once. Also, when drawing a plurality of lines separately, there is a problem that it is difficult to control the lines to be applied, and lines with uniform thickness and width cannot be applied. 【0004】 Patent Document 2 discloses a liquid applicator in which the opening at the tip of the mouthpiece is divided by one or more partitions to form a plurality of holes, and the tassel tip branches along the holes. However, each flexible filament of the tassel tip tends to point in a random direction, and since it is a delicate operation of inserting from the rear end side of the mouthpiece and branching into holes of about 1 mm, assembly is difficult or a certain degree of skill is required. Also, since the tassel tip is evenly divided, there is a problem that only uniform lines can be drawn. 【Prior Art Documents】 【Patent Documents】 【0005】 [Patent Document 1] Japanese Utility Model Publication No. 7-35084 [Patent Document 2] Japanese Patent Publication No. 2023-083886 [Overview of the Initiative] [Problems that the invention aims to solve] 【0006】 This invention addresses the above circumstances and aims to provide a liquid applicator that can apply multiple lines at once and is easy to assemble. The inventors have found that by adjusting the shape of the mouthpiece opening, the tip of the brush can be branched into multiple bundles of bristles with capillary action, thus completing the present invention. [Means for solving the problem] 【0007】 To solve the above problems, the brush tip unit of the present invention comprises a single brush tip made of a monofilament with a tapered tip, and a mouthpiece provided to cover the outer circumference of the tip portion of the brush tip, excluding the tip end, wherein the tip of the brush tip branches into multiple bundles of bristles having capillary action when the brush tip is assembled to the mouthpiece and immersed in a coating liquid. 【0008】 The filament diameter of the brush tip may be 0.10 mm or more. 【0009】 It is desirable that the circumscribed rectangle of the cross-section of the opening at the tip of the mouthpiece has a longer side that is at least 1.8 times the length of its shorter side. 【0010】 The cross-section of the opening at the tip of the mouthpiece may be rectangular, approximately rectangular, elliptical, a concave lens shape in which the width in the direction of the shorter side of the center is smaller than the shorter side, or a concave lens shape in which the width in the direction of the shorter side of the center is smaller than the shorter side and the shorter side is rounded outwards. 【0011】 The brush may further include an intermediate core, and the outer circumference of the tip portion of the intermediate core may be covered by the rear end portion of the brush tip. 【0012】 The material of the brush tip may be a polyester tapered filament or a nylon tapered filament. 【0013】 The manufacturing method of the brush tip unit of the present invention includes a brush tip insertion step of inserting the brush tip from the rear end of the mouthpiece. 【0014】 Another method for manufacturing a brush tip unit of the present invention includes a relay core insertion step of inserting the tip portion of the relay core into the rear end portion of the brush tip, and a brush tip insertion step of inserting the brush tip from the rear end portion of the mouthpiece after the relay core insertion step. 【0015】 The liquid application device of the present invention uses the above-described brush tip unit. 【0016】 The liquid applicator of the present invention is a liquid applicator manufactured using the method for manufacturing the brush tip unit described above. [Effects of the Invention] 【0017】 The brush tip unit of the present invention allows for the application of two, three, or more lines at once, and it is also possible to create lines of varying widths. Furthermore, assembly is easy because the brush tip branches appropriately depending on the shape of the opening at the front of the mouthpiece simply by inserting the brush tip from the rear end. [Brief explanation of the drawing] 【0018】 [Figure 1] An example of a schematic diagram of the brush tip unit of the present invention is shown. Figure 1(a) is a side view seen from above in the short-side direction of the opening at the tip of the mouthpiece, Figure 1(b) is a side view seen from above in the long-side direction of the opening at the tip of the mouthpiece, and Figure (c) is a perspective view. [Figure 2]Fig. 2(a) shows a photograph of an example of the nib unit of the present invention. Fig. 2(b) is a photograph when the application liquid is impregnated in Fig. 2(a). [Figure 3] An example of the mouthpiece of the present invention is shown. Fig. 3(a) is a side view seen from the tip side of the mouthpiece, Fig. 3(b) is a longitudinal sectional view cut in the long side direction so as to pass through the center of the short side of the opening at the tip of the mouthpiece, Fig. 3(c) is a longitudinal sectional view cut in the short side direction so as to pass through the center of the long side of the opening at the tip of the mouthpiece, and Fig. 3(d) is a perspective view. [Figure 4] An example of a side view of the mouthpiece of the present invention seen from the tip side is shown. The cross section of the opening in Fig. 4(a) is rectangular, Fig. 4(b) is a rectangular shape with rounded corners, Fig. 4(c) is a concave lens shape in which the width of the center part in the short side direction is smaller than the short side and the center part of the long side of the rectangle is concave, Fig. 4(d) is a concave lens shape in which the width of the center part in the short side direction is smaller than the short side and the short side is rounded outward, Fig. 4(e) is an elliptical shape, Fig. 4(f) is a small wave shape, Fig. 4(g) is a large wave shape, Fig. 4(h) is a double concave lens shape in which two concave parts are formed on the long side of the rectangle, and Fig. 4(i) is a triple concave lens shape in which three concave parts are formed on the long side of the rectangle. [Figure 5] It is a figure showing the circumscribed rectangle of the cross section of the opening at the tip of the mouthpiece of the present invention. The cross section of the opening in Fig. 5(a) is rectangular, Fig. 5(b) is a rectangular shape with rounded corners, Fig. 5(c) is a concave lens shape in which the width of the center part in the short side direction is smaller than the short side and the center part of the long side of the rectangle is concave, Fig. 5(d) is a concave lens shape in which the width of the center part in the short side direction is smaller than the short side and the short side is rounded outward, Fig. 5(e) is an elliptical shape, Fig. 5(f) is a small wave shape, Fig. 5(g) is a large wave shape, Fig. 5(h) is a double concave lens shape in which two concave parts are formed on the long side of the rectangle, and Fig. 5(i) is a triple concave lens shape in which three concave parts are formed on the long side of the rectangle. [Figure 6] Fig. 6(a) shows an example of a longitudinal sectional view of the liquid applicator of the present invention, and Fig. 6(b) shows an example of a longitudinal sectional view of the nib unit of the present invention. 【Embodiments for Carrying Out the Invention】 【0019】 The nib unit of the present invention includes a nib and a mouthpiece. An example is shown in FIGS. 1 to 6. Hereinafter, it will be described with reference numerals, but it does not limit the present invention. In the present specification, the "tip portion" refers to the foremost end portion (position) on the tip side of the liquid applicator in each component or part, the "rear end portion" refers to the last end portion (position) on the side opposite to the tip of the liquid applicator in each component or part, the "tip part" refers to the tip portion and the vicinity of the tip portion in each component, and the "rear end part" refers to the rear end portion and the vicinity of the rear end portion in each component. Also, the "tip side" refers to the tip side, and the "rear end side" refers to the side opposite to the tip. 【0020】 (Configuration of the nib) The nib 3 of the present invention is provided for writing with the liquid supplied from a relay core 4 described later from the rear end portion of the nib 3 or with the liquid immersed in the tip part of the nib 3 at the tip of the tip part of the nib 3. The nib 3 is defined by a mouthpiece 2 or the like that covers the outer periphery of the part of the tip part of the nib 3 excluding the tip. Also, one nib 3 is inserted into one mouthpiece 2. 【0021】 The nib 3 is composed of a monofilament with a tapered tip part. The material of the nib 3 is not particularly limited as long as it is a tapered monofilament and is arbitrarily selected. Examples of the material of the nib 3 include polyester tapered filaments such as PBT (polybutylene terephthalate) tapered filaments, PET (polyethylene terephthalate) tapered filaments, PTT (polytrimethylene terephthalate) tapered filaments, nylon tapered filaments, PPS (polyphenylene sulfide) tapered filaments, fluororesin tapered filaments, and the like. Among them, from the aspect of versatility, PBT (polybutylene terephthalate) tapered filaments and nylon tapered filaments are preferable. 【0022】 The filament diameter of the monofilament of the brush tip 3 is set appropriately depending on the application and purpose of the liquid applicator 10 in which this brush tip unit 1 is used. From the standpoint of brush feel and skin feel, a range of 0.05 to 0.30 mm is preferred, and the ranges of 0.10 to 0.28 mm, 0.10 to 0.24 mm, and 0.10 to 0.20 mm are more preferred. In addition, the monofilament of the brush tip 3 may be a mixture of multiple filament diameters. For example, a 0.10 mm monofilament and a 0.15 mm monofilament may be mixed in a ratio of 1:9 to 9:1. 【0023】 The total length of the brush tip 3 is 15mm to 35mm, and the diameter of the base is 2mm to 6mm as an example. To ensure that the rear end of the brush tip 3 covers the outer circumference of the tip of the intermediate core 4, for example, the intermediate core 4 may be inserted into the brush tip 3. Preferably, a hole is provided at the rear end of the brush tip 3 to facilitate insertion of the intermediate core 4. The diameter of the hole is the same as, or slightly smaller than, the outer diameter of the tip side of the intermediate core 4. If insertion is possible due to the elasticity of the intermediate core 4, the diameter of the hole in the brush tip 3 may be slightly smaller than the outer diameter of the tip side of the intermediate core. 【0024】 In order to position the mouthpiece 2, which covers the outer circumference of the tip portion of the brush tip 3 excluding the brush tip, so as not to shift position at the rear end of the brush tip 3, it is preferable that the mouthpiece 2 covers the outer circumference of the entire portion of the brush tip 3 other than the tip (including the rear end portion), and that a flange portion is provided at the rear end of the brush tip 3. The flange portion can contact the rear end of the mouthpiece 2 to fix its position, and examples include a flange portion diameter of about 2.5 mm to 7.0 mm and a flange portion thickness of about 0.3 mm to 2.5 mm. The hole and flange can be formed, for example, by cutting a bundle of monofilaments with tapered tips to a predetermined length (slightly longer than the total length of the brush tip) at the rear end, welding the cut surfaces together by heating, forming a flange during welding, hollowing out the center of the welded cut surface in a circular shape with the diameter of the hole in the brush tip 3, and removing the monofilaments welded to the center of the hollowed-out cut surface. The diameter of the hole is typically around 1.0 mm to 2.5 mm. 【0025】 The shape of the cross-section of the rear end portion (excluding the flange) of the brush tip 3 is not particularly limited as long as it can be inserted along the shape of the inner cross-section of the rear end portion of the mouthpiece 2, which will be described later, but examples include circular, elliptical, square, rectangular, and polygonal shapes with rounded corners. Among these, a rounded circular or elliptical shape or a polygonal shape with rounded corners is preferred from the viewpoint of making it easier to smoothly insert the tip of the brush tip 3 into the mouthpiece 2, and a circular or nearly circular elliptical shape is preferred from the viewpoint of not having to adjust the relative rotation direction of the brush tip 3 and the mouthpiece 2 during assembly. 【0026】 When the tip of the brush end 3 is assembled to the mouthpiece 2 (described later) and immersed in the application liquid, it branches into multiple bundles of bristles with capillary action due to the shape of the opening of the mouthpiece 2. Three or more branches are preferable, and four or more are even preferable. 【0027】 (Mouthpiece construction) The mouthpiece 2 of the present invention is provided so as to cover the outer circumference of the tip portion of the brush tip 3, excluding the tip end. As shown in Figures 3 to 5, examples of cross-sectional shapes of the opening at the tip of the mouthpiece 2 include rectangles, rounded rectangles, elliptic shapes, concave lens shapes where the width in the direction of the shorter side of the center is smaller than the shorter side, concave lens shapes where the width in the direction of the shorter side of the center is smaller than the shorter side and the shorter side is rounded outwards, small wave shapes, large wave shapes, double concave lens shapes, triple concave lens shapes, etc. Among these, from the viewpoint of branching of the tip end of the brush tip 3, rectangles, rounded rectangles, elliptic shapes, concave lens shapes where the width in the direction of the shorter side of the center is smaller than the shorter side, or concave lens shapes where the width in the direction of the shorter side of the center is smaller than the shorter side and the shorter side is rounded outwards are preferred. By shaping the cross-section of the opening at the tip of the mouthpiece 2 in these ways, when the application liquid is immersed in the brush tip 3, the force that would cause the brush tip 3 to converge can be released towards the long side. In particular, a concave lens shape allows the force that would cause the brush tip 3 to converge to converge even more effectively towards the long side. 【0028】 The circumscribed rectangle of the cross-section of the opening at the tip of the mouthpiece 2 has a longer side length 2b that is 1.8 times or more than the shorter side length 2a, and more preferably 2.0 times or more. As the length of the longer side 2b shortens and approaches the length of the shorter side 2a, the brush tip 3 tends to merge into a single unit, making it difficult to branch into multiple strands of hair, and thus preventing the application of multiple lines at once. On the other hand, if the length of the shorter side 2a becomes too short, the brush tip 3 will be crushed too much at the opening. As a result, the tip of the brush 3 will not have the appropriate cohesion, and the tip will spread out too much, preventing capillary action from working. In other words, it will not form multiple bundles of hair that have capillary action, and it will not be possible to draw a line with a proper cluster. Furthermore, if the length of the shorter side 2a becomes too small, depending on the diameter of the monofilament of the brush tip 3, it may not be possible to insert it into the opening at the tip of the mouthpiece 2, making assembly impossible. For example, if the diameter of the monofilament is 0.10 mm, and the length of the shorter side 2a of the circumscribed rectangle needs to be at least 0.5 mm, then if the length of the longer side 2b is 2.8 mm, then the length of the longer side 2b will be 5.6 times the length of the shorter side 2a. This calculation is merely an example, but for the circumscribed rectangle of the cross-section of the opening at the tip of the mouthpiece 2, it is preferable that the length of the longer side 2b is approximately 10 times or less the length of the shorter side 2a, and more preferably 9.3 times or less, or 5.6 times or less. 【0029】 Here, the circumscribed rectangle of the cross-section of the opening at the tip of mouthpiece 2 is the rectangle that is tangent to the figure of the cross-section of the opening. The circumscribed rectangle of Figure 4(a) is shown in Figure 5(a), the circumscribed rectangle of Figure 4(b) is shown in Figure 5(b), the circumscribed rectangle of Figure 4(c) is shown in Figure 5(c), the circumscribed rectangle of Figure 4(d) is shown in Figure 5(d), the circumscribed rectangle of Figure 4(e) is shown in Figure 5(e), the circumscribed rectangle of Figure 4(f) is shown in Figure 5(f), the circumscribed rectangle of Figure 4(g) is shown in Figure 5(g), the circumscribed rectangle of Figure 4(h) is shown in Figure 5(h), and the circumscribed rectangle of Figure 4(i) is shown in Figure 5(i). 【0030】 If the cross-sectional shape of the opening at the tip of the mouthpiece 2 is a concave lens shape with the center of the long side of the rectangle being concave, the way the tip of the brush 3 branches can also be changed by the minimum distance 2d in the short side direction. Note that if the minimum distance 2d in the short side direction is too small, depending on the diameter of the monofilament of the brush 3, it may not be possible to insert it into the opening at the tip of the mouthpiece 2, making assembly difficult. 【0031】 Figure 3(a) is a side view of the mouthpiece 2 as seen from the tip side, Figure 3(b) is a longitudinal section of the mouthpiece 2 cut along the long side, passing through the center of the short side of the opening at the tip, Figure 3(c) is a longitudinal section of the mouthpiece 2 cut along the short side, passing through the center of the long side of the opening at the tip, and Figure 3(d) is a perspective view of the mouthpiece 2. The length of the shorter side 2a of the circumscribing rectangle of the cross-section of the opening at the tip of the mouthpiece 2 is typically 0.3 mm to 3.0 mm, preferably 0.3 mm to 1.3 mm. When the length of the shorter side 2a is 0.3 mm to 1.3 mm, the branched bristles tend to line up in a horizontal row, or if the shape of the opening at the tip of the mouthpiece is a small wave shape or a large wave shape, the branched bristles tend to line up in a zigzag horizontal row. The length of the longer side 2b of the circumscribing rectangle is typically 2.0 mm to 6.0 mm. The length of the longitudinal section 2c of the mouthpiece 2 is typically 5 mm to 20 mm. The minimum distance 2d in the direction of the shorter side of the cross-section of the opening at the tip of the mouthpiece 2 is typically 0.3 mm to 1.5 mm. 2a' is the length of the shorter side of the opening at the rear end of the mouthpiece 2, and 2b' is the length of the longer side of the opening at the rear end of the mouthpiece 2. When the cross-section of the opening at the rear end is approximately circular, 2a' and 2b' are approximately equal, and a range of about 2.0 mm to 6.0 mm is exemplified. Furthermore, as shown in Figures 3(b) and 3(c), if there is a step at the rear end of the mouthpiece 2, the position of the mouthpiece 2 can be fixed to the flange of the brush tip 3. 【0032】 Figure 4 shows an example of a side view of mouthpiece 2 as seen from the tip. In Figure 4(a), the cross-section of the opening at the tip of mouthpiece 2 is rectangular; in Figure 4(b), it is a rectangle with rounded corners; in Figure 4(c), it is a concave lens shape with the center of the long side of the rectangle being concave; in Figure 4(d), it is a concave lens shape with the short side rounded outwards; in Figure 4(e), it is an ellipse; in Figure 4(f), it is a small wave shape; in Figure 4(g), it is a large wave shape; in Figure 4(h), it is a double concave lens shape with two recesses formed on the long side of the rectangle; and in Figure 4(i), it is a triple concave lens shape with three recesses formed on the long side of the rectangle. Figure 5 shows the circumscribed rectangles of each cross-section in Figure 4. 【0033】 The cross-section of the opening at the rear end of the mouthpiece 2 is appropriately selected to have a shape and area that allows for the insertion of the connecting core 4, making it easy to insert the brush tip 3 and supplying a sufficient amount of liquid to the brush tip 3. In addition to circular and elliptical shapes, polygonal shapes such as triangles, squares, and rectangles with rounded corners may also be used. Among these, circular, nearly circular elliptical, and polygonal shapes with rounded corners are preferred from the viewpoint of making it easy to smoothly insert the tip of the brush tip 3 into the mouthpiece 2, and circular, nearly circular elliptical, etc. are preferred from the viewpoint of not having to adjust the relative rotation direction of the brush tip 3 and the mouthpiece 2 during assembly. 【0034】 The material of mouthpiece 2 is not particularly restricted as long as it can secure the brush tip; ABS resin, PP resin, etc., are commonly used. Furthermore, the external shape of the mouthpiece 2 is designed taking into consideration the shape of the liquid applicator 10 that houses the brush tip unit 1. Injection molding is an example of a manufacturing method for the mouthpiece 2. 【0035】 (Configuration of the relay core) The intermediate core 4 is a core provided to supply liquid from the rear end of the brush tip 3, that is, to "relay" the liquid to the brush tip 3, and its tip is polished in a tapered shape. The rear end of the intermediate core 4 is immersed in the liquid, and the liquid is drawn up to the tip by the capillary force of the intermediate core 4. The outer circumference of the tip of the intermediate core 4 is covered by the rear end of the brush tip 3, and the liquid drawn up by the capillary force is supplied to the brush tip 3. 【0036】 The material of the intermediate core 4 can be arbitrarily selected, having a porous structure that allows liquid to be supplied to the brush tip 3 by capillary force. Examples include nylon fibers, polyester fibers, acrylic fibers, or mixtures thereof. There are no particular restrictions on the porosity of the intermediate core 4; for example, a porosity of approximately 30-90% can be appropriately selected. Furthermore, examples of materials for the relay core 4 include porous synthetic resins such as polyethylene terephthalate (PET), polybutylene terephthalate, polyacetal, polyamides such as nylon, polyethylene, polypropylene, acrylic resin, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, Teflon®, ABS resin, AS resin, polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, and polyimide. The size of the intermediate core 4 is set appropriately depending on the cross-sectional shape and cross-sectional area of ​​the rear end of the brush tip 3 into which it is inserted, the intended use of the liquid applicator 10, etc., but it is desirable that the diameter be about 1.5 mm to 3.0 mm and the length be about 25 mm to 60 mm. 【0037】 (Brush tip unit) The brush tip unit 1 comprises a single brush tip 3 as described above, and a mouthpiece 2 provided to cover the outer circumference of the tip portion of the brush tip 3, excluding the tip end. When the brush tip 3 is assembled to the mouthpiece and immersed in the coating liquid, the tip of the brush tip 3 branches into multiple bundles of bristles that have capillary action. Figure 2(a) is a photograph of the brush tip 3 and mouthpiece 2 before immersion in the coating liquid, and Figure 2(b) is a photograph of the brush tip 3 in Figure 2(a) after it has been impregnated with the coating liquid. Furthermore, the brush tip unit 1 may further include a connecting core 4, wherein the outer circumference of the tip portion of the connecting core 4 is covered by the rear end portion of the brush tip 3. The brush tip unit 1 including the connecting core 4 is illustrated in Figure 1. Figure 1(a) is a side view of the opening at the tip of the mouthpiece seen from above in the direction of the short side, Figure 1(b) is a side view of the opening at the tip of the mouthpiece seen from above in the direction of the long side, and Figure 1(c) is a perspective view. 【0038】 The method for assembling (manufacturing) the brush tip unit includes a brush tip insertion step in which the brush tip 3 is inserted from the rear end of the mouthpiece 2. Furthermore, it is desirable to include a relay core insertion step before the brush tip insertion step in which the tip portion of the relay core 4 is inserted into the rear end portion of the brush tip 3. Here, when the tip of the brush 3 is branched according to the shape of the opening of the mouthpiece 2, the tip separates, but when immersed in the coating liquid, it branches into multiple bundles of hair that have capillary action (see Figure 2(b)). Since the fibers of the brush tip stick together due to capillary action in each branched bundle (bundle of hair), it becomes possible to draw multiple lines. Furthermore, a step of trimming the tips of the branched brush heads may be included for visual inspection before shipment as parts. For example, by immersing the tip of each brush head in a 0.1% aqueous solution of PVA (polyvinyl alcohol), the fibers can be bound together by surface tension and the shape can be adjusted. 【0039】 (Liquid applicator) The brush tip unit 1 of the present invention is applicable to various liquid application tools 10 such as cosmetic tools and writing instruments (see Figures 6(a) and 6(b)). In addition to the intermediate core 4, the liquid application method can also be a cotton type or a direct liquid type. For example, it can be applied to cosmetic liquid applicators such as eyeliner, eyeshadow, eyebrow pencil, lip liner, lip gloss, concealer, nail care products, and eyelash care products. Furthermore, it can be applied to writing liquid applicators such as oil-based markers, water-based markers, board markers, line markers, paint markers, correction pens, medical markers, and drug application devices. [Examples] 【0040】 The following describes specific embodiments of the present invention, but the present invention is not limited in any way to these embodiments. 【0041】 (Example 1) —The tip of the brush— A bundle of 0.2mm diameter PBT (polybutylene terephthalate) monofilaments with tapered tips was used to create a brush tip 3 with a base diameter of 3.0mm, an overall length of 16.0mm, a flange outer diameter of 3.7mm, a flange thickness of 0.6mm, and an insertion hole diameter of 1.2mm for the intermediate core 4. 【0042】 —Mouthpiece— A mouthpiece 2 was used, which was injection-molded from polypropylene. In its longitudinal section, its length 2c was 9.7 mm, the opening at the rear end was circular with inner diameters 2a' and 2b' of 3.1 mm, and the cross-section of the opening at the front end was a concave lens shape with the shorter side rounded outwards, with the longer side 2b of the circumscribed rectangle being 3.1 mm, the shorter side 2a being 1.2 mm, and the minimum distance 2d in the direction of the shorter side being 0.5 mm. That is, 2b / 2a = 2.58. 【0043】 —Relay Core— A porosity 60% intermediate core 4 was used, which was a molded body made of polyester fiber with an outer diameter of 2.0 mm, a total length of 35 mm, a stepped diameter of 1.2 mm, and a single filament diameter of 5 denier, and polyurethane resin. 【0044】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0045】 -Assembly into a liquid applicator for evaluation testing- The assembled brush tip unit was placed in a container containing a cotton core (single filament diameter 5d, porosity 90%) filled with 0.7g of eyebrow dye ink with a viscosity of 2.5 cps, specific gravity 1.00, and pH 7.4, thereby obtaining a liquid applicator 10 for evaluation testing. 【0046】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation tests are shown in Tables 1 and 2. 【0047】 (Example 2) —The tip of the brush— The same brush tip 3 as in Example 1 was used. 【0048】 —Mouthpiece— A mouthpiece 2 was used, which was injection-molded from polypropylene. It had a longitudinal cross-section length 2c of 9.7 mm, a circular opening at the rear end with inner diameters 2a' and 2b' of 3.1 mm, and a rectangular cross-section at the front opening, with the longer side 2b of the (circumscribed) rectangle being 3.1 mm and the shorter side 2a being 0.8 mm. That is, 2b / 2a = 3.88. 【0049】 —Relay Core— The same relay core 4 as in Example 1 was used. 【0050】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0051】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator 10 for evaluation testing was obtained in the same manner as in Example 1. 【0052】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation test are shown in Table 1. 【0053】 (Example 3) —The tip of the brush— The same brush tip 3 as in Example 1 was used. 【0054】 —Mouthpiece— A mouthpiece 2 was used, which was injection-molded from polypropylene, with a longitudinal cross-section length 2c of 9.7 mm, a circular opening at the rear end with inner diameters 2a' and 2b' of 3.1 mm, and an elliptical cross-section at the front opening with a circumscribed rectangle, long side 2b of 3.1 mm and short side 2a of 1.2 mm. That is, 2b / 2a = 2.58. 【0055】 —Relay Core— The same relay core 4 as in Example 1 was used. 【0056】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0057】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator 10 for evaluation testing was obtained in the same manner as in Example 1. 【0058】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation test are shown in Table 1. 【0059】 (Example 4) —The tip of the brush— The same brush tip 3 as in Example 1 was used. 【0060】 —Mouthpiece— A mouthpiece 2 was used, which was injection-molded from polypropylene. In its longitudinal section, its length 2c was 9.7 mm, the opening at the rear end was circular with inner diameters 2a' and 2b' of 3.1 mm, and the cross-section of the opening at the front end was concave lens-shaped, with the long side 2b of the circumscribed rectangle being 2.8 mm, the short side 2a being 1.3 mm, and the minimum distance 2d in the short side direction being 0.5 mm. That is, 2b / 2a = 2.15. 【0061】 —Relay Core— The same relay core 4 as in Example 1 was used. 【0062】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0063】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator 10 for evaluation testing was obtained in the same manner as in Example 1. 【0064】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation test are shown in Table 1. 【0065】 (Example 5) —The tip of the brush— The same brush tip 3 as in Example 1 was used. 【0066】 —Mouthpiece— A mouthpiece 2 was used, which was injection-molded from polypropylene, with a longitudinal cross-section length 2c of 9.7 mm, a circular opening at the rear end with inner diameters 2a' and 2b' of 3.1 mm, and a rectangular cross-section at the front opening, with the longer side 2b of the (circumscribed) rectangle being 2.8 mm and the shorter side 2a being 1.3 mm. That is, 2b / 2a = 2.15. 【0067】 —Relay Core— The same relay core 4 as in Example 1 was used. 【0068】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0069】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator 10 for evaluation testing was obtained in the same manner as in Example 1. 【0070】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation test are shown in Table 1. 【0071】 (Example 6) —The tip of the brush— A bundle of 0.25mm diameter PBT (polybutylene terephthalate) monofilaments with a tapered tip was used to create a brush tip 3 with a base diameter of 3.0mm, an overall length of 16.0mm, a flange outer diameter of 3.7mm, a flange thickness of 0.6mm, and an insertion hole diameter of 1.2mm for the intermediate core 4. 【0072】 —Mouthpiece— The same mouthpiece 2 as in Example 1 was used. 【0073】 —Relay Core— The same relay core 4 as in Example 1 was used. 【0074】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0075】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator 10 for evaluation testing was obtained in the same manner as in Example 1. 【0076】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation test are shown in Table 2. 【0077】 (Example 7) —The tip of the brush— A bundle of 0.15mm diameter PBT (polybutylene terephthalate) monofilaments with a tapered tip was used to create a brush tip 3 with a base diameter of 3.0mm, an overall length of 16.0mm, a flange outer diameter of 3.7mm, a flange thickness of 0.6mm, and an insertion hole diameter of 1.2mm for the intermediate core 4. 【0078】 —Mouthpiece— The same mouthpiece 2 as in Example 1 was used. 【0079】 —Relay Core— The same relay core 4 as in Example 1 was used. 【0080】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0081】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator 10 for evaluation testing was obtained in the same manner as in Example 1. 【0082】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation test are shown in Table 2. 【0083】 (Example 8) —The tip of the brush— A brush tip 3 was created by mixing a 0.15mm diameter PBT (polybutylene terephthalate) monofilament with a tapered tip and a 0.10mm diameter PBT (polybutylene terephthalate) monofilament with a tapered tip in a 50:50 ratio and bundling them together. The resulting brush tip had a base diameter of 3.0mm, an overall length of 16.0mm, a flange outer diameter of 3.7mm, a flange thickness of 0.6mm, and an insertion hole diameter for the intermediate core 4 of 1.2mm. 【0084】 —Mouthpiece— The same mouthpiece 2 as in Example 1 was used. 【0085】 —Relay Core— The same relay core 4 as in Example 1 was used. 【0086】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip 3 was inserted from the rear end of the mouthpiece 2, bringing the flange of the brush tip 3 into contact with the step on the mouthpiece 2. The tip of the brush tip 3 was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of mouthpiece 2, and it was possible to insert them smoothly. 【0087】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator 10 for evaluation testing was obtained in the same manner as in Example 1. 【0088】 —Evaluation Test— Using the liquid applicator 10 for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines with a narrow line width. The results of the evaluation test are shown in Table 2. 【0089】 (Comparative Example 1) —The tip of the brush— The same brush tip as in Example 1 was used. 【0090】 —Mouthpiece— A mouthpiece was used that was injection-molded from polypropylene, with a longitudinal cross-section length 2c of 9.7 mm, a circular opening at the rear end with inner diameters 2a' and 2b' of 3.1 mm, and a rectangular cross-section at the front opening, with the longer side 2b of the (circumscribed) rectangle being 2.5 mm and the shorter side 2a being 1.5 mm. That is, 2b / 2a = 1.67. 【0091】 —Relay Core— The same relay core as in Example 1 was used. 【0092】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip was inserted from the rear end of the mouthpiece, and the flange of the brush tip was brought into contact with the step in the mouthpiece. The tip of the brush tip was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of the mouthpiece, and it was possible to insert them smoothly. 【0093】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator for evaluation testing was obtained in the same manner as in Example 1. 【0094】 —Evaluation Test— Using a liquid applicator designed for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was not possible to write multiple lines. The results of the evaluation test are shown in Table 1. 【0095】 (Comparative Example 2) —The tip of the brush— The same brush tip as in Example 1 was used. 【0096】 —Mouthpiece— A mouthpiece was used that was injection-molded from polypropylene, with a longitudinal cross-section length 2c of 9.7 mm, a circular opening at the rear end with inner diameters 2a' and 2b' of 3.1 mm, and a concave lens-shaped cross-section at the front opening, with a circumscribed rectangle whose long side 2b is 2.5 mm, short side 2a is 2.0 mm, and the minimum distance 2d in the short side direction is 1.2 mm. That is, 2b / 2a = 1.25. 【0097】 —Relay Core— The same relay core as in Example 1 was used. 【0098】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip was inserted from the rear end of the mouthpiece, and the flange of the brush tip was brought into contact with the step in the mouthpiece. The tip of the brush tip was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles did not get stuck in the opening at the tip of the mouthpiece, and it was possible to insert them smoothly. 【0099】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator for evaluation testing was obtained in the same manner as in Example 1. 【0100】 —Evaluation Test— Using a liquid applicator designed for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was not possible to write multiple lines. The results of the evaluation test are shown in Table 1. 【0101】 (Comparative Example 3) —The tip of the brush— The brush tip was constructed by bundling 0.15mm diameter PBT (polybutylene terephthalate) monofilaments with tapered tips, resulting in a base diameter of 3.2mm, an overall length of 18.2mm, a flange outer diameter of 3.9mm, a flange thickness of 0.6mm, and a core insertion hole diameter of 1.45mm. 【0102】 —Mouthpiece— Polypropylene is injection molded, with a length of 11.6 mm in the longitudinal section and an opening at the rear end. It is circular with an inner diameter of 3.2 mm, and the opening at the tip is elliptical with two partitions, creating three holes. The distance between the centers of the holes is 1.225 mm, and the area of ​​the central hole is 1.40 mm². 2 The area of ​​the holes on either side is 1.24 mm². 2 Therefore, a mouthpiece was used. 【0103】 —Relay Core— The same relay core as in Example 1 was used. 【0104】 —Assembling the brush tip unit— After inserting the tip of the connecting core 4 into the hole at the rear end of the brush tip 3, the brush tip was inserted from the rear end of the mouthpiece, and the flange of the brush tip was brought into contact with the step in the mouthpiece. The tip of the brush tip was immersed in a 0.1% PVA aqueous solution, shaped, and dried. During assembly, the bristles could be inserted into the three holes in the opening at the tip of the mouthpiece. However, skill and technique were required to branch the bristles in a manner roughly proportional to the area of ​​the holes. Therefore, Comparative Example 3 was less easy to assemble compared to the embodiment without partitions in the opening. 【0105】 -Assembly into a liquid applicator for evaluation testing- A liquid applicator for evaluation testing was obtained in the same manner as in Example 1. 【0106】 —Evaluation Test— Using a liquid applicator designed for evaluation testing, multiple lines were written on paper with a writing load of 1g, confirming that it was possible to write multiple lines. The results of the evaluation test are shown in Table 1. 【0107】 [Table 1] 【0108】 [Table 2] 【0109】 In Tables 1 and 2, the evaluation of whether multiple lines could be written was based on the following criteria: when the brush tip was dipped in the coating liquid, a ○ indicated that the brush tip branched into three or more branches, and a × indicated that it did not. Table 3 shows examples of photographs of the branching state of the brush tip and the writing state for each of the ○ and × cases. 【0110】 [Table 3] 【0111】 Within the scope of the evaluation tests shown in Table 1, a comparison of Examples 1-5 and Comparative Examples 1 and 2 revealed that if the ratio of the length of the longer side 2b to the length of the shorter side 2a (2b / 2a) of the circumscribing rectangle of the cross-section of the opening at the tip of the mouthpiece 2 is at least 1.67, it becomes impossible to write multiple thin lines, and if the ratio exceeds this, it becomes possible to write multiple thin lines. Furthermore, in Comparative Example 3, which has a partition at the opening of the tip of the mouthpiece, it was found that although it was possible to write multiple lines, the ease of assembling the brush tip and mouthpiece was lower compared to Examples 1-5 or Comparative Examples 1 and 2. 【0112】 Table 2 shows the results of evaluation tests where the shape of mouthpiece 2 was kept the same, but the filament diameter was changed. Within the scope of the evaluation tests, it was found that it was possible to write multiple lines with a narrow line width even when the filament diameter was changed, as shown in Examples 1, 6-8. Assembly was easy in all cases. 【0113】 The present invention may have the following configurations: [Section 1] A single brush tip made of a tapered monofilament, A mouthpiece is provided to cover the outer circumference of the tip portion of the brush, excluding the tip end, Equipped with, The brush tip unit is such that when the brush tip is assembled to the mouthpiece and immersed in the application liquid, it branches into multiple bundles of bristles that have capillary action. [Section 2] The brush tip unit according to item 1 above, wherein the filament diameter of the brush tip is 0.10 mm or more. [Section 3] The brush tip unit according to item 1 or 2, wherein the circumscribing rectangle of the cross-section of the opening at the tip of the mouthpiece has a longer side that is 1.8 times or more than the shorter side. [Section 4] The brush tip unit according to any one of items 1 to 3 above, wherein the cross-section of the opening at the tip of the mouthpiece is rectangular, substantially rectangular, elliptical, a concave lens shape in which the width in the direction of the shorter side of the center is smaller than the shorter side, or a concave lens shape in which the width in the direction of the shorter side of the center is smaller than the shorter side and the shorter side is rounded outwards. [Section 5] Equipped with additional relay cores, The outer circumference of the tip portion of the relay core is covered by the rear end portion of the brush tip, as described in any one of items 1 to 4 above. [Section 6] The brush tip unit according to any one of items 1 to 5 above, wherein the material of the brush tip is a polyester tapered filament or a nylon tapered filament. [Section 7] A method for manufacturing the brush tip unit described in item 1 above, The brush tip insertion step involves inserting the brush tip from the rear end of the mouthpiece, A method for manufacturing a brush tip unit, including the method described above. [Section 8] A method for manufacturing a brush tip unit as described in item 5 above, The intermediate core insertion step involves inserting the tip portion of the intermediate core into the rear end portion of the brush tip, Following the intermediate core insertion step, there is a brush tip insertion step in which the brush tip is inserted from the rear end of the mouthpiece, A method for manufacturing a brush tip unit, including the method described above. [Section 9] A liquid applicator using a brush tip unit as described in any one of items 1 to 6 above. [Section 10] A liquid applicator manufactured using the method for manufacturing a brush tip unit as described in item 7 or 8 above. [Explanation of symbols] 【0114】 1 brush tip unit 2 mouthpieces 2a. The length of the shorter side (inner diameter) of the circumscribed rectangle of the cross-section of the opening at the tip of the mouthpiece. 2a' Length of the shorter side (inner diameter) of the opening at the rear end of the mouthpiece. 2b. The length of the longer side (inner diameter) of the circumscribed rectangle of the cross-section of the opening at the tip of the mouthpiece. 2b' Length of the longer side (inner diameter) of the opening at the rear end of the mouthpiece. 2c Length of the mouthpiece in the longitudinal section Minimum distance in the short-side direction of the cross-section of the opening at the tip of the 2D mouthpiece. 3. Brush tip 4 relay cores 10 Liquid applicators

Claims

[Claim 1] A single brush tip made of a tapered monofilament, A mouthpiece is provided to cover the outer circumference of the tip portion of the brush, excluding the tip end, Equipped with, The brush tip unit is such that when the brush tip is assembled to the mouthpiece and immersed in the application liquid, it branches into multiple bundles of bristles that have capillary action. [Claim 2] The brush tip unit according to claim 1, wherein the filament diameter of the brush tip is 0.10 mm or more. [Claim 3] The brush tip unit according to claim 1 or 2, wherein the circumscribing rectangle of the cross-section of the opening at the tip of the mouthpiece has a longer side that is 1.8 times or more than the shorter side. [Claim 4] The brush tip unit according to claim 1 or 2, wherein the cross-section of the opening at the tip of the mouthpiece is rectangular, substantially rectangular, elliptical, a concave lens shape in which the width in the direction of the shorter side of the center is smaller than the shorter side, or a concave lens shape in which the width in the direction of the shorter side of the center is smaller than the shorter side and the shorter side is rounded outwards. [Claim 5] Equipped with additional relay cores, The brush tip unit according to claim 1 or 2, wherein the outer circumference of the tip portion of the relay core is covered by the rear end portion of the brush tip. [Claim 6] The brush tip unit according to claim 1 or 2, wherein the material of the brush tip is a polyester tapered filament or a nylon tapered filament. [Claim 7] A method for manufacturing a brush tip unit according to claim 1, The brush tip insertion step involves inserting the brush tip from the rear end of the mouthpiece, A method for manufacturing a brush tip unit, including the method described above. [Claim 8] A method for manufacturing a brush tip unit according to claim 5, The intermediate core insertion step involves inserting the tip portion of the intermediate core into the rear end portion of the brush tip, Following the intermediate core insertion step, there is a brush tip insertion step in which the brush tip is inserted from the rear end of the mouthpiece, A method for manufacturing a brush tip unit, including the method described above. [Claim 9] A liquid applicator using the brush tip unit described in claim 1. [Claim 10] A liquid applicator manufactured using the method for manufacturing a brush tip unit as described in claim 7.

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