JP2006112008A - Bristle material for brush, method for producing the same and brush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bristle material for brush having excellent chemical resistance and heat resistance and high cleaning efficiency in the form of a brush and provide a method for producing the bristle material and a brush. <P>SOLUTION: The bristle material for brush is composed of a monofilament composed mainly of a tetrafluoroethylene copolymer and having 0.010-0.040% of a surface irregularity S defined by formulae (I), (II) and (III) wherein ΔD<SB>n</SB>is the absolute value of the difference between the diameters D<SB>n</SB>and D<SB>n+1</SB>at adjacent two measuring points n and n+1 (n is a natural number) determined by measuring the diameter of the monofilament along the fiber axis at intervals of 1.5 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bristle material for a brush that is excellent in chemical resistance and heat resistance and has high cleaning efficiency when used as a brush, a method for producing the same, and a brush.

  Brush materials made of thermoplastic resin and brushes using the same have been used for various applications. In addition, various types of thermoplastic resins, such as polyamide-based resins, polyester-based resins, polyolefin-based resins, and fluorine-based resins, have been used as the thermoplastic resin constituting the bristle material depending on the brush application and required characteristics.

  In particular, various industrial brushes such as roll brushes, linear brushes, wheel brushes, cup brushes, hebel brushes, torsion brushes, and niblet brushes are used because they are susceptible to various physical and chemical effects. The bristle material is required to have proper characteristics according to its use.

  On the other hand, in recent years, IT-related technologies and information-related technologies have expanded, and the demand for flat panel displays used for TVs, personal computers, mobile phones and the like has increased. In particular, the demand for liquid crystal displays will continue to increase, and the market is actively expanding in various countries and manufacturers.

  Since the cost of liquid crystal displays varies depending on the number of panels cut out from a single mother glass, the mother glass for liquid crystal displays has been increasing in size for the purpose of cost reduction, and the efficiency has increased with the increase in size in the manufacturing process. It is out.

  The liquid crystal display manufacturing process includes a cleaning process. In this cleaning process, a solvent is used as a cleaning agent under high temperature conditions to improve cleaning efficiency. Excellent chemical resistance and heat resistance are required.

  It has been well known that a fluororesin is a polymer having excellent chemical resistance, and fibers made of this fluororesin are already known. As these conventional examples, for example, polytetrafluoroethylene-based modified cross-section fibers (for example, see Patent Document 1), carbon component content is 0.1 to 0.5% by weight, crystal orientation is 92% or more, tensile strength 2.0 g / d or more polytetrafluoroethylene fiber (for example, refer to Patent Document 2), single fineness of 3000 d or less, strength of 1.2 g / d or more, cross-sectional major axis / minor axis ratio 5: 4 to 1: 1, decomposition A polytetrafluoroethylene fiber having a carbon component content of 1% by weight or less (see, for example, Patent Document 3), and a perfluorinated thermoplastic copolymer of tetrafluoroethylene having a melt flow rate of 1 to 30 g / min, and having a tensile strength of Fluoropolymer fibers having a linear shrinkage of less than 15% in a temperature range of 190 MPa or more and 40 to 60 ° C. lower than the melting point of the copolymer (for example, see Patent Document 4)

  However, when these fibers made of fluororesins are used as industrial brush hair materials such as cleaning brushes used in the cleaning process of liquid crystal display manufacturing, they have excellent chemical resistance, but are resistant to heat. Not only is it not sufficient, but fluororesins have high water and oil repellency, so it is easy to repel cleaning liquids, and the hair surface is slippery, resulting in low friction with the object to be cleaned, resulting in low cleaning efficiency. was there.

Further, there is known a brush (see, for example, Patent Document 5) in which the flocked surface of the brush handle is divided into a plurality of flocked areas, and fluorine fibers are implanted in one of the flocked areas adjacent to each other and non-fluorinated fibers are implanted in the other. However, this brush is characterized by lowering the static charge and facilitating the removal of dust from clothes and carpets. When applied as an industrial brush, it is also resistant to chemicals and heat. The cleaning efficiency was not sufficient.
JP-A-63-219616 Japanese Patent Application Laid-Open No. 8-199421 JP-A-8-296113 JP-T-2002-504197 JP 59-186509 A

  The present invention has been achieved as a result of studying the solution of the above-described problems in the prior art as an object, and is excellent in chemical resistance and heat resistance, and has a high cleaning efficiency when used as a brush. The object is to provide a manufacturing method and a brush.

In order to achieve the above object, according to the present invention, a monofilament comprising a tetrafluoroethylene-based copolymer as a main component, the diameter of the monofilament is measured at intervals of 1.5 mm along the fiber axis direction, and continuous 2 One measuring point n and n + 1 (n is a natural number) the absolute value of the difference between the diameter D _n and D _{n + 1} in the case of the [Delta] D _n, M the mean value of the common logarithm of the [Delta] D _n represented by the following formula (I) The average value of ΔD _n represented by the following formula (II) is ΔD _AV, and the surface roughness ratio S represented by the following formula (II) is 0.010 to 0.040%. A brush bristle material is provided.

However, k is a natural number and represents the total number of measurement points.

Moreover, in the brush hair material of this invention, satisfy | filling the conditions of following (1)-(3) is all preferable conditions, and when these conditions are applied, the further excellent effect is acquired. can do.
(1) The melt viscosity measured according to ASTM D3307 of the tetrafluoroethylene-based copolymer is 15 to 40 g / 10 minutes.
(2) The tetrafluoroethylene copolymer is a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer.
(3) The Young's modulus measured according to JIS L1013: 1999 8.10 of the monofilament is 1500 to 3000 N / mm ² .

  Further, in the method for producing the brush hair material of the present invention, when the tetrafluoroethylene copolymer is melt-spun, it is melt-kneaded at a temperature 20 to 100 ° C. higher than its melting point, and then discharged from the die hole at a discharge rate of 0.5. The monofilament extruded by ˜1.5 m / min, subsequently cooled, stretched and wound up is cut into a desired length.

  Furthermore, the brush of the present invention is a brush using the above-mentioned brush hair material as at least a part of the hair material, and particularly when used as a brush used in a liquid crystal screen cleaning process, has high cleaning efficiency and excellent practical use. Demonstrate sex.

  According to the present invention, as described below, it is possible to obtain a bristle material for a brush that is excellent in chemical resistance and heat resistance and has high cleaning efficiency when used as a brush.

  In addition, the brush of the present invention has high cleaning efficiency, and is extremely useful as a brush in a liquid crystal screen cleaning process using a solvent as a cleaning liquid under high temperature conditions.

  The present invention will be specifically described below.

In order to obtain brush hair material that has excellent chemical resistance and heat resistance, and has high cleaning efficiency when used as a brush, the brush hair material consists of a monofilament composed mainly of a tetrafluoroethylene copolymer. The diameter of the monofilament is measured at 1.5 mm intervals along the fiber axis direction, and the absolute value of the difference between the diameters D _n and D _{n + 1} at two consecutive measurement points n and n + 1 (n is a natural number) is ΔD _n The average value of the common logarithm of ΔD _n represented by the following formula (I) is M, and the average value of ΔD _n represented by the following formula (II) is ΔD _AV, and is represented by the following formula (III) It is necessary that the surface irregularity S is from 0.010 to 0.040%.

However, k is a natural number and represents the total number of measurement points.

  That is, in the liquid crystal screen cleaning process, since a solvent is used as a cleaning liquid under high temperature conditions, the material constituting the brush bristle material used for such applications must have excellent chemical resistance and heat resistance. Therefore, the bristle material for brushes of the present invention is required to be made of a tetrafluoroethylene copolymer having excellent chemical resistance and heat resistance among fluorine resins.

  Examples of the tetrafluoroethylene-based copolymer used in the present invention include a tetrafluoroethylene / hexafluoropropylene copolymer, an ethylene / tetrafluoroethylene copolymer, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, and Examples include tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride copolymers. Among these, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymers having particularly excellent chemical resistance and heat resistance are preferably used. The

  However, since the tetrafluoroethylene-based copolymer has many fluorine atoms bonded to the polymer molecule, when used as a brush hair material, the surface of the hair material is slippery, In addition to the problem that the friction is reduced and the cleaning effect is reduced, there is a problem that the cleaning liquid is easily repelled due to high water repellency and oil repellency and the cleaning efficiency is lowered.

  As a means for solving this problem, it is conceivable to add an inorganic abrasive or abrasive to the bristle material for the brush. In this case, the brush can be used during use by containing an inorganic abrasive or abrasive. Not only does the problem such as a decrease in strength of the hair material and breakage of hair occur, but also an inorganic abrasive or abrasive material is eroded by the cleaning liquid, so that a further decrease in strength or breakage is more likely to occur.

  Therefore, in the bristle material for brushes of the present invention, in order to increase the cleaning efficiency of the bristle material for brushes without using inorganic abrasives or abrasives, appropriate irregularities are intentionally imparted to the surface of the bristle material. It is characterized by that.

  However, the greater the surface irregularity of the brush hair material, the higher the cleaning efficiency when using a brush. On the other hand, if the surface irregularity is too large, the quality of the strength and bending hardness are likely to vary. In addition, it is not preferable because the hair is easily bent or broken.

  Therefore, it is necessary to represent the degree of surface irregularities for obtaining cleaning efficiency by numerical values and to control the surface irregularities appropriately to obtain the brush hair material of the present invention. The degree of surface irregularities is generally expressed by the difference in diameter between two points in the fiber axis direction of the bristle material for brushes, but the value of the difference in diameter varies from several hundred to several thousand times depending on the measurement location. If the diameter difference is simply arithmetically averaged over the wide range described above, it is difficult to say that the average value represents the true surface irregularity of the brush hair material.

However, in the present invention, the common logarithm of the diameter difference between the measurement points is averaged using the above formula (I), and the average value of the diameter difference between the measurement points is calculated from the average value M using the above formula (II). If the sought [Delta] D _AV, the surface irregularity degree-of brush bristles can be adequately represented, the quality of the cleaning efficiency and the brush bristles in the case of the brush can be accurately evaluated.

  Therefore, in the bristle material for brushes of the present invention, the surface unevenness ratio S represented by the above formula (III) is set to a range of 0.010 to 0.040%, particularly 0.010 to 0.025%. It is an important requirement.

  Here, when the surface unevenness ratio S is below the above range, it is difficult to obtain sufficient cleaning efficiency in the case of a brush, and conversely, when the above range is exceeded, the quality of the brush hair material varies. In the case of a brush, it is not preferable because the hair is easily bent or broken.

  It should be noted that the brush hair material of the present invention may optionally include a heat-resistant agent, a weather-resistant agent, a light-resistant agent, an anti-oxidant, an antistatic agent, a dye and a pigment as long as the object of the present invention is not impaired. can do.

  In addition, the viscosity of the tetrafluoroethylene copolymer measured according to ASTM D3307 is 15 to 40 g, because it can be stably produced and a bristle material for brushes with less variation in quality can be obtained. / 10 minutes, and particularly preferably 20 to 35 g / 10 minutes. When the melt viscosity of the tetrafluoroethylene-based copolymer is below the above range, the surface irregularities of the resulting brush bristle material become large, so that not only the quality tends to vary, but also the hair when used as a brush. Bending and breakage are likely to occur, and melt fracture occurs when monofilaments are melt-spun, which may result in an undesirable tendency that the base is easily soiled or broken.

  On the other hand, if the melt viscosity of the tetrafluoroethylene copolymer exceeds the above range, it becomes difficult to obtain appropriate surface irregularities on the brush hair material, and if it is made into a brush, it becomes a hair material with low cleaning efficiency. In addition, since the degree of polymerization of the polymer is low, the hair may be easily bent or broken.

Furthermore, in order that the bristle material for brushes of the present invention has appropriate flexibility as a brush, the Young's modulus measured in accordance with JIS L1013: 1999 8.10 of monofilament is 1500 to 3000 N / mm ² , especially 1800. It is preferably ˜2800 N / mm ² . If the Young's modulus of the monofilament is lower than the above range, the bristle and hips when used as a brush are too soft, so that the washing efficiency cannot be obtained sufficiently. In some cases, an undesired tendency to become a hair material that easily breaks.

  Next, the manufacturing method of the bristle material for brushes of this invention is demonstrated. About the manufacturing method of the monofilament used as the bristle material for brushes of this invention, it is not necessary to use any special manufacturing apparatus, For example, it can manufacture by using an extruder type or a melt pressure type melt spinning machine.

  However, in the production of monofilaments, when melt spinning using a tetrafluoroethylene copolymer as a raw material, the temperature is 20 to 100 ° C. higher than the melting point of the tetrafluoroethylene copolymer, particularly 30 to 80 ° C. When melt-kneading and extruding the melt of the tetrafluoroethylene copolymer from the die hole, the discharge rate of the copolymer melt is 0.5 to 1.5 m / min, especially 0.8 per one die hole. It is necessary to discharge under the condition of ~ 1.2 m / min.

  When the melting temperature of the spinning machine is lower than the above range, not only the pressure rises in the melt spinning machine but also it is difficult to obtain appropriate surface irregularities on the monofilament, which is not preferable. Conversely, if the spinning temperature of the spinning machine exceeds the above range, the surface irregularities of the monofilament will increase, and this will not only cause variations in the quality of the monofilament, but will also cause bending and breakage of the hair when used as a brush. This is not preferable because melt fracture occurs during melt spinning, and the base stain and thread breakage tend to occur.

  Also, when the discharge rate of the copolymer melt is below the above range, it is difficult to obtain appropriate surface irregularities on the monofilament, and conversely, if it exceeds the above range, the surface irregularities of the monofilament will increase, so the quality of the monofilament As a brush, hair is likely to bend or break, and when melt spinning, melt fracture occurs, and the base becomes dirty and breaks easily. Therefore, it is not preferable.

  Then, the copolymer melt extruded at the above discharge speed is cooled and solidified in a cooling bath, and subsequently, under a temperature condition of 120 to 180 ° C. in order to obtain an appropriate Young's modulus as a brush bristle material. The film is stretched by heating 5 to 5.5 times, and further subjected to a heat relaxation treatment as necessary to be wound. Then, the wound monofilament is cut into a length corresponding to the brush application and used as a hair material.

  The cross-sectional shape perpendicular to the fiber axis direction of the brush bristle material of the present invention is circular, hollow, flat, square, half moon, triangular, five or more polygons, multileaf, dockbone, and heel A type etc. are mentioned, It does not specifically limit.

  The brush of the present invention is a known production method such as using the bristle material for a brush obtained by the production method described above as at least a part of the bristle material, and planting the bristle material on a base such as a handle. can get.

  As described above, the bristle material for brushes of the present invention is excellent in chemical resistance and heat resistance, as well as a roll brush, a linear brush, a wheel brush, a cup brush, a hebel-type brush, a torsion-type brush, a niblet brush, and the like. LCD screen cleaning that uses a solvent as a cleaning solution, especially at high temperatures, with high cleaning efficiency when used on at least part of various brushes for various types of general brushes and various brushes such as industrial brushes, clothes brushes, and hair brushes When used for a brush in a process, its usefulness is extremely high.

  Hereinafter, although the hair material for brushes of the present invention will be described in detail with reference to examples, the present invention is not limited to the following examples unless it exceeds the gist. The physical properties of the brush hair material of the present invention are values measured by the following method.

[Evaluation of surface roughness and average diameter]
A method for measuring the diameter of a monofilament to be used as a bristle material for a brush and how to obtain the surface unevenness ratio S representing the surface unevenness state will be described with reference to FIG.

Using the KL506A SLB DIA MEASURING SYSTEM manufactured by Anritsu, the diameter of the monofilament 1 having a yarn length of 1 m running at a speed of 15 mm / sec was measured at a constant interval of L = 1.5 mm along the fiber axis direction, and the measurement points n (n is a natural number) and the diameter _{D n} of.

Next, the absolute value [Delta] D _n at regular intervals L = two consecutive difference in diameter _{D n} and _{D n + 1} at the measuring point n and n + 1 of 1.5 mm, the common logarithm of the [Delta] D _n using the following formula (I) The average value M was calculated. Next, the average value ΔD _AV of ΔD _n was calculated using the following formula (II), and the surface roughness ratio S was calculated using the following formula (III). The formula on the molecular side (in parentheses) of the following formula (III) represents the arithmetic average value of the diameters of the measurement points. The larger the surface irregularity value, the larger the surface irregularity of the monofilament.

However, k is a natural number and represents the total number of measurement points.

[Melt viscosity]
Measured according to ASTM D3307.

〔Young's modulus〕
Measured according to JIS L1013: 1999, 8.10.

[Quality variation due to tensile strength]
The tensile strength of the monofilament was measured according to 8.5 of JIS L1013: 1999. The number of measurements was 10 times, and quality variations due to tensile strength were evaluated in the following three stages.
○: When the difference between the maximum value and the minimum value of tensile strength is less than 15% of the arithmetic average value of all measured values,
Δ: When the difference between the maximum value and the minimum value of tensile strength is 15% or more and less than 25% of the arithmetic average value of all measured values,
X: When the difference between the maximum value and the minimum value of the tensile strength is 25% or more of the arithmetic average value of all measured values.

〔chemical resistance〕
Three monofilament pieces cut into 50 cm were added to 500 ml of a stripping solution 502A (mixture of aromatic hydrocarbon 60% by weight, phenol 20% by weight, and alkylbenzene sulfonic acid 20% by weight) manufactured by Tokyo Ohka Kogyo Co., Ltd. It was immersed for 15 hours at 75 ° C. and evaluated in the following two stages.
○: The monofilament piece remained without melting,
X: The monofilament piece was partially melted or completely unmelted.

[Stained base and yarn-making properties]
The following three stages were evaluated for the spinning condition of the monofilament for 20 hours from the start of the melt spinning of the monofilament and the condition of the die surface after 20 hours.
○: There was no dirt on the base and no thread breakage during yarn production.
Δ: The base was slightly dirty, but there was no thread breakage during yarn production.
X: The base was very dirty and thread breakage frequently occurred during yarn production.

[Cleaning efficiency]
Roll brushes were created using the brush bristle materials obtained in the examples and comparative examples, and the roll brushes were actually used in the cleaning process of the liquid crystal display production line. Then, the cleaning efficiency of the roll brush was evaluated in the following three stages.
○: There was no dirt on the substrate surface, and it was washed sufficiently.
Δ: Some dirt remains on the substrate surface, and the cleaning is slightly insufficient.
X: Dirt remained on the substrate surface and cleaning was insufficient.

[Example 1]
Ethylene / tetrafluoroethylene copolymer resin pellets (manufactured by Daikin Industries, Ltd., Fullon ETFE-C88AXP, melt viscosity of 28.5 g / 10 min) are supplied to an extruder type melt spinning machine with a diameter of 30 mm and a temperature of 290 ° C. After being melt-kneaded in the melt, it was melt-extruded from the die hole at a discharge speed of 1.24 m / min, led to warm water at 50 ° C. and solidified by cooling. Subsequently, the cooled and solidified undrawn yarn was drawn 4.8 times in a dry heat bath at 150 ° C., and further subjected to a heat relaxation treatment of 0.95 times to obtain a monofilament having a diameter of 0.1 mm. Table 1 shows the measurement results of the physical properties of the monofilament and the cleaning efficiency evaluation results when using a brush.

[Examples 2, 4 to 5]
Tetrafluoroethylene / peralkyl vinyl ether copolymer resin pellets (Asahi Glass Co., Ltd., P-62XP, melt viscosity 30.2 g / 10 min) were supplied to an extruder type melt spinning machine with a diameter of 30 mm and a temperature of 380 ° C. After melt-kneading, the mixture was melt-extruded from the nozzle hole at the discharge speed shown in Table 1, and led to warm water at 50 ° C. to be cooled and solidified. Subsequently, the cooled and solidified undrawn yarn was drawn 4.5 times in a dry heat bath at 150 ° C., and further subjected to a heat relaxation treatment of 0.85 times to obtain a monofilament having a diameter of 0.1 mm. Table 1 shows the results of physical properties of monofilaments and the results of cleaning efficiency evaluation in the case of a brush.

Example 3
Tetrafluoroethylene / peralkyl vinyl ether copolymer resin pellets (manufactured by Daikin Industries, Ltd., AP-210, melt viscosity 18.0 g / 10 min) were supplied to an extruder type melt spinning machine with a diameter of 30 mm at 380 ° C. After melt-kneading at a temperature, it was melt-extruded from the die hole at a discharge speed of 0.79 m / min, led to warm water at 50 ° C. and solidified by cooling. Subsequently, the cooled and solidified undrawn yarn was drawn 4.5 times in a dry heat bath at 150 ° C., and further subjected to a heat relaxation treatment of 0.85 times to obtain a monofilament having a diameter of 0.1 mm. Table 1 shows the measurement results of the physical properties of the monofilament and the cleaning efficiency evaluation results when using a brush.

[Comparative Example 1]
Polyvinylidene fluoride resin pellets (manufactured by SOLVAY SOLEXIS, SOLEF 1012, melt viscosity measured according to ASTM D1238 is 5.0 g / 10 min) are supplied to an extruder type melt spinning machine of φ30 mm and melted at a temperature of 230 ° C. After kneading, it was melt-extruded from the die hole at a discharge speed of 0.51 m / min, led to warm water at 20 ° C. and solidified by cooling. Subsequently, the cooled and solidified undrawn yarn was drawn 6.0 times in a high-temperature polyethylene glycol bath and a dry heat bath, and further subjected to a heat relaxation treatment of 0.90 times to obtain a monofilament having a diameter of 0.1 mm. Table 1 shows the measurement results of the physical properties of the monofilament and the cleaning efficiency evaluation results when using a brush.

[Comparative Examples 2 and 4]
Tetrafluoroethylene / peralkyl vinyl ether copolymer resin pellets (Asahi Glass Co., Ltd., P-62XP, melt viscosity 30.2 g / 10 min) were supplied to an extruder type melt spinning machine with a diameter of 30 mm and a temperature of 380 ° C. After melt-kneading, the mixture was melt-extruded from the nozzle hole at the discharge speed shown in Table 1, and led to warm water at 50 ° C. to be cooled and solidified. Subsequently, the cooled and solidified undrawn yarn was drawn 4.5 times in a dry heat bath at 150 ° C., and further subjected to a heat relaxation treatment of 0.85 times to obtain a monofilament having a diameter of 0.1 mm. Table 1 shows the measurement results of the physical properties of the monofilament and the cleaning efficiency evaluation results when using a brush.

[Comparative Example 3]
Tetrafluoroethylene / peralkyl vinyl ether copolymer resin pellets (manufactured by Asahi Glass Co., Ltd., P-66P, melt viscosity of 3.0 g / 10 min) are supplied to an extruder melt spinning machine with a diameter of 30 mm and a temperature of 380 ° C. After being melt-kneaded in the melt, it was melt-extruded from the die hole at a discharge speed of 0.40 m / min, led to warm water at 50 ° C. and solidified by cooling. Subsequently, the cooled and solidified undrawn yarn was drawn 4.5 times in a dry heat bath at 150 ° C., and further subjected to a heat relaxation treatment of 0.85 times to obtain a monofilament having a diameter of 0.1 mm. Table 1 shows the measurement results of the physical properties of the monofilament and the cleaning efficiency evaluation results when using a brush.

  As is apparent from the results in Table 1, the brush bristle material (Examples 1 to 6) satisfying the conditions of the present invention is excellent in chemical resistance and quality, and has high cleaning efficiency when used as a brush. . However, when a tetrafluoroethylene-based polymer having a low melt viscosity is used (Example 3), or when the discharge speed at the time of melt spinning is high (Example 5), the contamination of the die and the variation in quality are slightly increased. There is a trend.

  On the other hand, the bristle material for brushes (Comparative Examples 1 to 4) that does not satisfy the conditions of the present invention has problems such as poor chemical resistance, variation in quality, and contamination of the base. The cleaning efficiency when using a brush was low.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in chemical resistance and heat resistance, the bristle material for brushes with the high washing | cleaning efficiency at the time of setting it as a brush can be acquired.

  In addition, the brush of the present invention uses a brush bristle material having the above-mentioned characteristics as at least a part of the bristle material, has high cleaning efficiency, and uses a solvent as a cleaning liquid particularly under high temperature conditions. Very useful as a brush in the process.

It is explanatory drawing of the evaluation method of the diameter and surface unevenness | corrugation state of a monofilament.

Explanation of symbols

1 Monofilament n nth measurement point (natural number)
D _n Diameter at the nth measurement point L Distance between successive measurement points (1.5 mm)

Claims (7)

It consists of a monofilament whose main component is a tetrafluoroethylene-based copolymer. The diameter of the monofilament is measured at 1.5 mm intervals along the fiber axis direction, and the diameter at two consecutive measurement points n and n + 1 (n is a natural number). the absolute value of the difference D _n and _{D n + 1} in case of the [Delta] D _n, the [Delta] D _n represented the average value of common logarithm of the [Delta] D _n represented by the following formula (I) M, by the following formula (II) An average value is ΔD _AV, and the surface irregularity ratio S represented by the following formula (III) is 0.010 to 0.040%.

However, k is a natural number and represents the total number of measurement points. The bristle material for brushes according to claim 1, wherein the tetrafluoroethylene copolymer has a melt viscosity of 15 to 40 g / 10 minutes measured according to ASTM D3307. The bristle material for brush according to claim 1 or 2, wherein the tetrafluoroethylene-based copolymer is a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer. The JIS monofilament L1013: 1999 brush bristle material according to claim 1, the measured Young's modulus according to 8.10 characterized in that it is a 1500~3000N / mm ² of. When melt spinning the tetrafluoroethylene-based copolymer, it is melt-kneaded at a temperature 20 to 100 ° C. higher than its melting point, and then extruded from the die hole at a discharge speed of 0.5 to 1.5 m / min, followed by cooling and stretching. The method for producing a bristle material for a brush according to any one of claims 1 to 4, wherein the monofilament wound up is cut into a desired length. A brush comprising the brush bristle material according to any one of claims 1 to 4 as at least a part of the bristle material. The brush according to claim 6, wherein the brush is used in a liquid crystal screen cleaning process.

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