JP2020175608A - Brush tip and liquid applicator having brush tip - Google Patents

Abstract

To provide a brush tip having flexibility as fibers of the brush tip, in aspects of a kind of fibers, a chemical structure of fibers, fiber diameters, a crimping degree and a recovery degree after deformation, and a liquid applicator having the brush tip.SOLUTION: A brush tip is formed in a desired shape after bundling fibers having 50% or more of a 20% elongation recovery ratio and bonding with a resin binder. Further, a bulky ratio of the fibers is set 125% or less. Further, polytrimethylene terephthalate fibers are used for the fibers. Further, a single yarn of the fiber is set to 4 dtex or less, and polyurethane resin is used for the resin binder. A liquid applicator has the brush tip.SELECTED DRAWING: None

Description

The present invention relates to a brush tip used for a liquid coating tool such as a writing instrument or a cosmetic tool, and a liquid coating tool provided with the brush tip.

Fiber-made brush tips used in brush-type writing instruments and cosmetics are made by bundling fibers in the longitudinal direction, adhering them with a resin binder, and then grinding the tips into a desired shape such as a brush.
Nylon fiber and polyester fiber have been mainly used as the material of the fiber of the brush tip.

The reason why nylon fibers have been widely used is that nylon fibers are flexible, have good adhesion to an adhesive binder, and easily exhibit functions as a brush tip (stopping, splashing, shavings, etc.). However, although it was understood that the highly flexible fiber is not limited to nylon, it has not been known what kind of fiber can obtain the flexibility of the brush tip equal to or higher than that of nylon fiber.

On the other hand, the brush tip of polyethylene terephthalate fiber, which is mainly used among polyester fibers, is inferior in flexibility to nylon fiber, and has a problem that it is difficult to exhibit the function as a brush tip (stop, splash, shaving, etc.). It was. In addition, due to friction between the brush tip and the object to be coated such as paper, the resin binder that adheres the fibers gradually peels off, and some of the bundled fibers are separated and cannot recover to the shape at the time of molding, so-called. There was also a problem that the fibers were scattered from each other.

In other words, the simple selection of the material of "nylon fiber or polyester fiber", which is the type of fiber material, is more flexible as the fiber of the brush tip and functions as the brush tip (stop, splash, shaving, etc.). ) Is more easily expressed, and it has been difficult to provide a brush tip having a feature of high shape recovery.

Japanese Unexamined Patent Publication No. 2-295799

The present invention has been made in view of the above circumstances, and not only the type of fiber of the brush tip, but also the chemical structure, fiber diameter (thinness), degree of crimping, and post-crimping of the same type of fiber. It is an object of the present invention to provide a brush tip having high flexibility and improved shape recovery by examining fibers having different heating states and tensile states.

In order to solve the above problems, the brush tip of the present invention is a brush tip in which fibers are bundled in the longitudinal direction, bonded with a resin binder, and then molded into a desired shape, and the 20% elongation recovery rate of the fibers is 50%. It is characterized by the above.

The bulkiness of the fiber is preferably 125% or less.

The fiber is preferably a polytrimethylene terephthalate fiber.

The single yarn of the fiber is preferably 4 dtex or less.

The resin binder is preferably a polyurethane resin.

The liquid coating tool of the present invention is characterized by including the above-mentioned brush tip.

According to the brush tip of the present invention, since the fiber having high elasticity having a 20% elongation recovery rate of 50% or more is provided, the recovery property of the shape of the brush tip can be improved.
Further, in addition to the above-mentioned elongation recovery rate, when the bulkiness rate of the brush tip is as low as 125% or less, that is, in the case of a brush tip provided with fibers having a low crimp rate of the molded product, the contact area between the fibers increases and the resin binder Adhesion area also increases. For this reason, the resin binder that adheres the fibers to each other is less likely to come off due to friction between the brush tip and the object to be coated such as paper, and it is possible to suppress the occurrence of loosening between the fibers.

An example of a scanning electron microscope (SEM) longitudinal cross-sectional photograph of the brush tip for each type of fiber of the brush tip is shown. An example of a microscope photograph of the appearance of the brush tip in the dispersal / deformation test for each type of fiber of the brush tip is shown.

The brush tip of the present invention uses a liquid supplied from the rear end portion of the brush tip, or immerses the liquid in the tip portion of the brush tip and applies the liquid to an object to be coated such as paper or skin.
Such a brush tip is obtained by bundling fibers in the longitudinal direction, passing them through a molding die, heat-processing them, impregnating them with a resin binder, drying them, adhering them, and then grinding them into a desired length and shape.

(20% elongation recovery rate of fiber)
The fiber of the brush tip of the present invention has a 20% elongation recovery rate of 50% or more, preferably 62% or more, and more preferably 65% or more.
The 20% elongation recovery rate indicates the recovery rate after 20% elongation of the fiber excluding the influence of slackening and crimping of the fiber (thread), and 100 when the fiber is restored to its original length. %, 0% when the length is extended.

The test method for the 20% elongation recovery rate of the present invention is as follows, and refers to the elongation elastic modulus B method of JIS L1013: 2010.
That is, the sample (fiber) is grasped at a grip interval of 20 cm, a load G0 is applied at a constant speed, and 3% (5%, 2%, if necessary) of the grip interval is stretched. The length at this time is L0. The reason why the 3% (5% or 2%) of the gripping interval is stretched in advance is that the length excluding slack and crimp of the fiber (thread) is used as a reference.
After extending 3% (5% or 2%) of the grip interval and holding for 1 minute, the load G0 is removed at the same speed and held for 3 minutes. After that, the load G1 is applied again at the same speed, and the load is stretched to 20% with respect to L0. The length at this time is L1.
After stretching to 20% of L0, the load G1 is removed, and the initial load G0 is applied again to stretch. The length at this time is L2.

The 20% elongation recovery rate (%) is expressed by the formula of Equation 1.

(Number 1)
20% elongation recovery rate (%) = {(L1-L2) / (L1-L0)} × 100

The average value of 5 times is rounded to an integer according to JIS Z8401 rule B (rounding method), and the obtained value is defined as a 20% elongation recovery rate.

For example, a load G0 is applied to a fiber (thread) having a gripping interval of 20 cm, and 0.6 cm is stretched by 3% of the gripping interval of 20 cm to 20.6 cm. At this time, L0 = 20.6 cm. After holding for 1 minute, remove the load G0 and hold for 3 minutes. After that, the load G1 is applied again at the same speed, and the load G1 is stretched to 24.72 cm, which is a 20% elongation with respect to L0. At this time, L1 = 24.72 cm. After stretching, the load G1 is removed, and the initial load G0 is applied to stretch. If the length L2 at this time is 21.6 cm, from the equation of Equation 1,
{(24.72-21.6) / (24.72-20.6)} x 100 = 75.7
Therefore, the 20% growth recovery rate is 76%.

When the 20% elongation recovery rate of the fiber is 50% or more, the elasticity of the brush tip is high, and the recovery of the shape of the brush tip can be improved.

(Bulk ratio of fiber bundle)
The bulkiness (%) of the fiber of the brush tip of the present invention is preferably 125% or less, more preferably 122% or less, and further preferably 120% or less.
The bulkiness ratio (%) is expressed by the formula of Equation 2, and the unit weight D1 (g / m) of the fiber bundle after molding is the apparent unit weight D2 (g / m) when the fiber bundle is straight. ) Divided and multiplied by 100.

(Number 2)
Bulkiness (%) = unit weight D1 / apparent unit weight D2 x 100

The unit weight D1 (g / m) of the fiber bundle after molding is obtained after the fibers are focused in the longitudinal direction and heat-processed through a molding die, and the fiber bundle before impregnation with the resin binder is used. The unit weight D1 (g / m) is calculated from the length and weight of the fiber bundle.
The apparent unit weight D2 (g / m) when the fiber bundle is straight is calculated by dividing the total decitex by 10,000. The decitex is a weight (g) per 10,000 m of fiber (thread).

When the fiber bundle of the brush tip is close to straight, the bulkiness ratio is small and approaches 100%, and when the fiber bundle of the brush tip is greatly crimped, the bulkiness ratio is large.

The bulkiness is affected by the crimped state of the fiber.
The fibers of the brush tip are usually crimped and then molded in order to improve moldability and secure a passage for a liquid such as ink. Since the fibers are heated and pulled during molding, the crimps of the fibers are also stretched, but the fibers after molding do not completely return to straight and have a crimped state. When the crimp ratio in the crimped state is high, the fiber bundle becomes bulky.

When the bulkiness ratio of the fiber bundle is as low as 125% or less, the crimp ratio is low, the contact area between the fibers increases, and the adhesive area of the resin binder also increases. For this reason, the resin binder that adheres the fibers to each other is less likely to come off due to friction between the brush tip and the object to be coated such as paper, and the occurrence of loosening between the fibers can be suppressed.

(Fiber thickness and fiber bundle diameter)
The diameter (thickness) of the fiber of the brush tip is exemplified in the range of 0.1 dtex to 11.1 dtex, preferably in the range of 0.5 dtex to 4.0 dtex, and more preferably in the range of 0.5 dtex to 2.0 dtex. In general, the smaller the diameter of the fiber, the larger the adhesive area with the resin binder, so that it becomes easier to suppress the occurrence of looseness between the fibers.

The diameter of the fiber bundle is appropriately set according to the purpose of the liquid coating tool such as a writing instrument or a cosmetic tool. In order to utilize the elasticity of the fiber and secure the adhesive area of the resin binder, the range of 0.5 mm to 10.0 mm is preferable, and the range of 2.0 mm to 7.0 mm is more preferable.

(Fiber material)
Synthetic fibers are used as the fibers of the brush tip, and acrylic fibers such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate of polyester fibers such as nylon (registered trademark) of polyamide fiber are used. Etc. are exemplified. Of these, polytrimethylene terephthalate is preferable. As described above, even if the same type of fiber material is used, the bulkiness ratio, which is one of the indicators of disintegration, differs depending on the diameter (thickness) of the fiber (thread) and the crimped state, and the fibers of the same category. Even so, the 20% elongation recovery rate, which is one of the indicators of flexibility, differs depending on the chemical structure (difference in carbon number, etc.).

Further, as long as the moldability is maintained, the passage of the liquid is secured, and the range corresponds to the 20% elongation recovery rate specified in the present invention, a plurality of types of the above fibers may be used, and even the same material may be rolled. Fibers having different shrinkage states may be bundled. Straight fibers may be mixed with crimped fibers and bundled. In addition to the elongation recovery rate specified in the present invention, it is more preferable if the range corresponds to the bulkiness rate specified in the present invention.

(Resin binder)
Examples of the resin binder of the brush tip of the present invention include polyurethane resin, phenoxy resin, epoxy resin, and melamine resin. A resin binder having high adhesiveness to the fiber material is preferable, and a polyurethane resin is more preferable for nylon fibers and polyester fibers.

(Liquid coating tool)
The brush tip of the present invention can be applied to liquid coating tools such as writing instruments and cosmetic tools.

Examples of the liquid application tool include writing tools that use a brush, such as a brush-type pen, a brush-type pen for fine lines, and a correction fluid. Examples of cosmetic tools include various cosmetic liners such as eyeliner and lip liner, nail polish brushes, eyebrow, eyeshadow, lipstick, and concealer.
Examples of the liquid used in the liquid coating tool include water-based and oil-based ones depending on the application of the coating tool.

Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

-Structure of brush tip-
In order to carry out various tests, the brush tips of the materials and diameters shown in Table 1 were prepared.

As shown in Table 1, in Sample 1, 52,128 1.3 dtex polytrimethylene terephthalate fibers were bundled in the longitudinal direction and passed through a molding die to be heat-processed to obtain an outer diameter of 4.4 mm, and a polyurethane resin was used. It is impregnated, dried, bonded, and then ground to form a brush shape having a length of 32.5 mm.
Sample 2 is obtained by bundling 17,088 polyethylene terephthalate fibers of 3.3 dtex in the longitudinal direction, passing them through a molding die, heat-processing them to obtain an outer diameter of 4.4 mm, impregnating them with polyurethane resin, drying them, adhering them, and then grinding them. It is shaped like a brush with a length of 32.5 mm.
Sample 3 is obtained by bundling 20,928 nylon 6 fibers of 3.3 dtex in the longitudinal direction, passing them through a molding die, heat-processing them to obtain an outer diameter of 4.4 mm, impregnating them with polyurethane resin, drying them, adhering them, and then grinding them. It is shaped like a brush with a length of 32.5 mm.

-20% elongation recovery rate and bulkiness-
The 20% elongation recovery rate and bulkiness rate were measured for the fibers of Samples 1 to 3 by the method described above.
The 20% elongation recovery rate of the polytrimethylene terephthalate fiber of Sample 1 was as high as 88%, the nylon 6 fiber of Sample 3 was 62%, and the polyethylene terephthalate fiber of Sample 2 was as low as 29%. That is, it was found that the polytrimethylene terephthalate fiber of Sample 1 is a fiber having higher elasticity than that of Sample 2 and Sample 3.

The bulkiness of the polytrimethylene terephthalate fiber of Sample 1 was as low as 103%, the polyethylene terephthalate fiber of Sample 2 was 110%, and the nylon 6 fiber of Sample 3 was 122%. That is, the polytrimethylene terephthalate fiber of the sample 1 is a fiber having a lower crimp ratio as compared with the sample 2 and the sample 3, the contact area between the fibers increases, and the adhesive area of the resin binder also increases. It turned out.

FIG. 1 shows a vertical cross-sectional photograph of the tip of a scanning electron microscope (SEM) of Samples 1 to 3. It was found that the polytrimethylene terephthalate fiber bundle of Sample 1 having a low bulkiness ratio had a small gap between the fibers.

-Evaluation test 1 (Pen built-in line width measurement)-
The brush tips of Samples 1 to 3 were incorporated into the pen body, and one day later, the pen-embedded line width was measured. The reason for leaving it for one day is to sufficiently permeate the liquid such as ink supplied from the rear end portion on the opposite side of the tip of the brush to the fibers of the brush tip and stabilize the supply of the liquid.
For pen-embedded line width measurement, place the coated paper on the scale, set the writing angle to 90 ° with respect to the coated paper, set the writing speed to 8 cm / s, and change the load in the order of 50 gf, 100 gf, 200 gf to write. Then, the line width of the handwriting was measured with a line width measuring device.

For the obtained line width, the rate of change of the line width when the load was 50 gf and 200 gf was calculated, and the results are shown in Table 1.
It was found that the tip of the polytrimethylene terephthalate fiber of Sample 1 had a large rate of change of 155%, the line width could be changed according to the load, that is, the writing pressure, and the fiber had high flexibility. If the line width can be changed according to the writing pressure, it becomes easier to write and apply with the intended line width (thickness).
On the contrary, the brush tip of the polyethylene terephthalate fiber of sample 2 has a change rate of 128%, which is smaller than that of sample 1, and it is difficult to change the line width (difficult to write) according to the load, that is, the writing pressure, and the flexibility as a fiber is low. It turned out.
With the brush tip of the nylon 6 fiber of Sample 3, the rate of change was 134%.

-Evaluation test 2 (test to confirm the disparity between fibers by zigzag writing)-
The brush tips of Samples 1 to 3 were incorporated into the pen body, and one day later, a zigzag writing test was conducted to confirm the disparity between the fibers.
In the zigzag writing test, a plain paper is placed, the writing angle is set to 70 ° with respect to the plain paper, the load is set to 200 gf, and the 2 cm wide zigzag writing is performed 50 reciprocations (50 zigzags) for 2 m. After that, the pen body is rotated 90 ° in the circumferential direction, the same 2 cm wide zigzag writing is performed 50 reciprocations (50 zigzags) for 2 m, and then the pen body is further rotated 90 ° in the circumferential direction repeatedly. Was done by. Every time such zigzag writing was performed for a total of 40 m, 100 m, 120 m, and 180 m, a microscope photograph was taken at a magnification of 25 times. Zigzag writing was done with n = 2. The scope photographs of each brush tip are shown in FIG. 2, and the results are shown in Table 1.

With the brush tip of the polytrimethylene terephthalate fiber of Sample 1, no variation between the fibers was observed. On the other hand, at the brush tip of the polyethylene terephthalate fiber of Sample 2, disparity between the fibers was observed at the time of writing at 40 m. At the tip of the nylon 6 fibers of Sample 3, no disparity between the fibers was observed until the time of writing at 120 m, but some disparity between the fibers was observed after writing at 180 m.
It is considered that the polytrimethylene terephthalate fiber of sample 1 has a smaller bulkiness ratio than the other samples and has a large adhesive area between the fibers and between the fibers and the resin binder, so that the fibers are suppressed from being separated from each other. ..

-Evaluation test 3 (evaluation of deformation by zigzag writing)-
The distance (deviation) between the tip of the brush tip and the center line of the brush tip was measured from the microscope photograph taken in the evaluation test 2, and the degree of deformation of the brush tip was evaluated. The larger the distance, the larger the degree of deformation, indicating that the shape of the brush tip is difficult to recover. The evaluation results are shown in Table 1.

The brush tip of the polytrimethylene terephthalate fiber of Sample 1 did not deform until the time of writing at 100 m, and even at the time of writing at 120 m and 180 m, the deviation from the center line was as small as 0.3 mm and 0.5 mm, respectively, and the shape of the brush tip. Was found to be easy to recover. On the other hand, it was found that the brush tip of the polyethylene terephthalate fiber of Sample 2 had a large deviation from the center line of 2.5 mm at the time of writing at 40 m, and the shape of the brush tip was harder to recover than that of Sample 1 and Sample 3. The tip of the nylon 6 fiber of sample 3 was not deformed until the time of writing at 100 m, and at the time of writing at 120 m and 180 m, the deviation from the center line was 1.1 mm and 1.5 mm, respectively, when compared with sample 1. Although the shape of the brush tip is a little difficult to recover, it was found that the shape of the brush tip is easy to recover when compared with Sample 2.

-Evaluation test 4 (Measurement of line width change by zigzag writing)-
Using the brush tips before and after the zigzag writing performed in the evaluation test 2, the line width was measured at a load of 50 gf, and the rate of change was calculated. The rate of change (%) is the line width of the brush tip after writing 180 m divided by the line width of the brush tip at the start and multiplied by 100. The results are shown in Table 1.

With the brush tip of the polytrimethylene terephthalate fiber of Sample 1, the rate of change in line width before and after zigzag writing was as small as 104%, and it was found that stable writing was possible. It was found that the rate of change in the line width before and after zigzag writing was 120% at the tip of the nylon 6 fiber of Sample 3 as compared with Sample 1, which was slightly larger than that of Sample 1. With the brush tip of the polyethylene terephthalate fiber of Sample 2, the deformation after writing at 180 m was large, and it was difficult to measure the rate of change.

-Evaluation test 5 (discoloration evaluation)-
108 pieces of samples 1 to 3 in which the brush tips were incorporated in the pen body were prepared, liquids of different colors were supplied to each, and discoloration evaluation was performed.
Place the evaluation pen body with the built-in brush tip horizontally in an oven at a temperature of 50 ° C, and immediately after assembling into the pen body, color the handwriting after 1 day, 1 week, 2 weeks, and 4 weeks. For comparison, the number of colors in which discoloration was observed was counted. The evaluation results are shown in Table 1.

No discoloration was observed in the brush tip of the polytrimethylene terephthalate fiber of Sample 1 and the brush tip of the polyethylene terephthalate fiber of Sample 2. On the other hand, the brush tip of the nylon 6 fiber of Sample 3 was found to be discolored in 17 colors after 1 day, 26 colors after 1 week, and 28 colors after 2 weeks. It was confirmed that the nylon fiber adsorbs a specific pigment compound in the liquid such as ink, so that the original color of the liquid is lost.

The above evaluation results are those of a brush tip having the configurations shown in Table 1. The brush tip of the present invention is appropriately configured according to the use of the liquid coating tool, the required writing pressure (load), the angle between the object to be coated and the brush, the color to be used, the period of use, and the like.

Claims (6)

A brush tip that is formed into a desired shape after the fibers are bundled in the longitudinal direction and bonded with a resin binder.
The tip of the brush has a 20% elongation recovery rate of the fiber of 50% or more. The brush tip according to claim 1, wherein the bulkiness of the fiber is 125% or less. The brush tip according to claim 1 or 2, wherein the fiber is a polytrimethylene terephthalate fiber. The brush tip according to any one of claims 1 to 3, wherein the single yarn of the fiber is 4 dtex or less. The brush tip according to any one of claims 1 to 4, wherein the resin binder is a polyurethane resin. A liquid coating tool comprising the brush tip according to any one of claims 1 to 5.

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