Coat layer

Abstract

To provide a coat layer capable of realizing a desired tactile feeling depending on the season.SOLUTION: A coat layer comprises a matrix resin and moisture-absorbing fine particles dispersed in the matrix resin. A dynamic friction coefficient F10 at a relative humidity of 10% and a dynamic friction coefficient F90 at a relative humidity of 90%, measured in a predetermined test, satisfy the following formula (1). (F90 / F10-1)×100<0 (1).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a coating layer. [Background technology]

[0002] Materials with excellent tactile sensation have been proposed so far.

[0003] Specifically, a synthetic leather has been proposed that includes a base layer and a resin layer (0.9 mm) that contains synthetic resin and hygroscopic fine particles (average particle size 3 μm) (for example, see Patent Document 1 below). ). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-089245 A Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, materials are required to have a texture that suits the season: specifically, a dry feel is required in summer, whereas a moist feel is required in winter.

[0006] The synthetic leather of Patent Document 1 uses hygroscopic microparticles and achieves a dry feel by adjusting the amount of increase in humidity inside the palm as measured by a specified test, but has the disadvantage of being unable to achieve the above-mentioned seasonal feel.

[0007] The present invention provides a coating layer that can provide a desired tactile feel depending on the season. [Means for solving the problem]

[0008] The present invention [1] comprises a matrix resin and moisture-absorbing fine particles dispersed in the matrix resin, and has a dynamic friction coefficient F at a relative humidity of 10% measured by the following test.10 and the coefficient of kinetic friction F at a relative humidity of 90% 90 is a coating layer that satisfies the following formula (1). (F 90 / F 10 -1)×100<0 (1) Test: The coating layer is left to stand for 3 hours under conditions of 25°C and 10% relative humidity. After that, the surface of the coating layer is subjected to a tactile evaluation machine (sliding speed 10 mm / sec, load 50 gf, sliding distance 10 mm) to measure the dynamic friction coefficient F at a relative humidity of 10%. 10 The coating layer is left to stand for 3 hours under conditions of 25°C and 90% relative humidity. After that, the dynamic friction coefficient F at 90% relative humidity is measured on the surface of the coating layer using a touch evaluation device (sliding speed 10 mm / sec, load 50 gf, sliding distance 10 mm). 90 Measure.

[0009] The present invention [2] includes the coating layer according to the above [1], in which the ratio of the average particle size of the moisture-absorbing fine particles to the thickness of the coating layer is 0.20 or more and 5.00 or less.

[0010] The present invention [3] is characterized in that the weight of the moisture-absorbing fine particles is 2.0 g / m 2 Exceeds 50.0g / m 2 The coating layer includes the coating layer described in [1] or [2] above, which is as follows:

[0011] The present invention [4] includes the coating layer according to any one of the above [1] to [3], which has a thickness of 10 μm or more and 270 μm or less.

[0012] The present invention [5] includes the coating layer according to any one of the above [1] to [4], in which the average particle size of the moisture-absorbing fine particles is 31 μm or more and 5000 μm or less. Effect of the Invention

[0013] The coating layer of the present invention has a dynamic friction coefficient F at a relative humidity of 10% measured by a predetermined test. 10 and the coefficient of kinetic friction F at a relative humidity of 90% 90 and satisfies the following formula (1). (F 90 / F 10 -1)×100<0 (1)

[0014] This allows the desired tactile sensation to be achieved depending on the season. [Brief description of the drawings]

[0015] [Figure 1] 1A and 1B are explanatory diagrams for explaining the tactile sensations of conventional materials in each season. Fig. 1A is an explanatory diagram for explaining the tactile sensation in winter. Fig. 1B is an explanatory diagram for explaining the tactile sensation in summer. [Diagram 2] 2A and 2B are explanatory diagrams for explaining the tactile sensation in each season in the coating layer of one embodiment of the present invention. Fig. 2A is an explanatory diagram for explaining the tactile sensation in winter. Fig. 2B is an explanatory diagram for explaining the tactile sensation in summer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The coating layer is formed from a coating layer composition.

[0017] The coating layer composition includes a matrix resin and moisture absorbing fine particles. That is, the coating layer includes a matrix resin and moisture absorbing fine particles.

[0018] <Matrix resin> The matrix resin is not particularly limited as long as it is a resin capable of dispersing moisture-absorbing particles, and examples thereof include polyurethane resin, (meth)acrylic resin, vinyl acetate resin, and polyacrylonitrile resin. In addition, monomer and polymer products using biomass raw materials may also be used.

[0019] As the matrix resin, preferably, a polyurethane resin is used.

[0020] The matrix resin can also be prepared as an aqueous dispersion in which the matrix resin is dispersed in water (aqueous dispersion of the matrix resin). As the aqueous dispersion of the matrix resin, preferably, an aqueous dispersion of a polyurethane resin (polyurethane dispersion) is used.

[0021] In the aqueous dispersion of the polyurethane resin, an aqueous polyurethane resin is selected as the polyurethane resin. The aqueous polyurethane resin is a polyurethane resin having a hydrophilic group. Examples of the aqueous polyurethane resin include polycarbonate-type aqueous polyurethane, polyether-type aqueous polyurethane, and polyester-type aqueous polyurethane.

[0022] As the water-based polyurethane resin, preferably, polycarbonate-type water-based polyurethane is used.

[0023] In addition, it is preferable to select a lacquer type that can form a coating layer by volatilizing water in an aqueous dispersion of a polyurethane resin.

[0024] As the matrix resin, commercially available products can also be used, specifically, Takelac W6110 (polycarbonate-type water-based polyurethane, lacquer type, manufactured by Mitsui Chemicals, Inc.) can be mentioned as a commercially available product.

[0025] The matrix resins can be used alone or in combination of two or more kinds.

[0026] The content of the matrix resin in the coating layer composition (coating layer) is, for example, 70 mass % or more, preferably 80 mass % or more, and for example, 99 mass % or less, preferably 95 mass % or less.

[0027] <Moisture-absorbing fine particles> Hygroscopic particulates include, for example, hygroscopic polymer particles and inorganic particles.

[0028] Examples of the hygroscopic polymer include polyamide particles and sodium polyacrylate particles. Also, monomer and polymer products using biomass raw materials may be used.

[0029] An example of the inorganic particles is silica particles.

[0030] As the moisture absorbing fine particles, preferably, moisture absorbing polymer particles are used, and more preferably, sodium polyacrylate particles are used.

[0031] The average particle size of the moisture absorbing fine particles is, for example, 31 μm to 5000 μm, preferably 35 μm to 1000 μm, more preferably 38 μm to 100 μm, and still more preferably 40 μm to 50 μm.

[0032] In detail, the average particle size of moisture-absorbing particles is calculated by the coefficient of kinetic friction F at a relative humidity of 10%. 10 (see below) The coefficient of kinetic friction F at a relative humidity of 90% 90 From the viewpoint of reliably reducing the average primary particle diameter (described later), for example, at a temperature of 25° C. and a relative humidity of 24%, the average primary particle diameter is 31 μm or more, preferably 35 μm or more, more preferably 38 μm or more, and even more preferably 40 μm or more; and from the viewpoint of reducing roughness of the coating layer, the average primary particle diameter is 5000 μm or less, preferably 1000 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0033] The average particle size of the moisture-absorbing fine particles can be determined by creating a particle size distribution curve using a laser diffraction / scattering particle size distribution analyzer and calculating the 50% by mass equivalent particle size.

[0034] The moisture-absorbing fine particles can be used alone or in combination of two or more kinds.

[0035] The content of the moisture absorbing fine particles in the coating layer composition (coating layer) is, for example, 1 mass % or more, preferably 5 mass % or more, and for example, 30 mass % or less, preferably 20 mass % or less.

[0036] The content ratio of the moisture-absorbing microparticles is, for example, 1 part by mass or more, preferably 5 parts by mass or more, more preferably 15 parts by mass or more, and for example, 40 parts by mass or less, preferably 30 parts by mass or less, per 100 parts by mass of the matrix resin.

[0037] <Additives> The coating layer composition contains additives at an appropriate ratio as necessary. That is, the coating layer contains additives at an appropriate ratio.

[0038] Examples of the additives include matting agents, pigments, antioxidants, ultraviolet absorbers, light stabilizers, crystal nucleating agents, flame retardants, and anti-mite agents.

[0039] The additives can be used alone or in combination of two or more kinds.

[0040] <Preparation of Coating Layer Composition> To prepare the coating layer composition, the matrix resin (or the aqueous dispersion of the matrix resin), the moisture-absorbing fine particles, and the additives to be added as required are mixed and stirred as required. Thus, the coating layer composition is prepared.

[0041] When an aqueous dispersion of a matrix resin is used in preparing the coating layer composition, the moisture-absorbing fine particles are dispersed in the water in the coating layer composition.

[0042] Furthermore, the coating layer composition can be diluted with water and / or an organic solvent, if necessary.

[0043] <Production of Coating Layer> The coating layer is formed from a coating layer composition.

[0044] Specifically, the coating layer can be obtained by applying a coating layer composition to the surface of the article to be coated, and then drying it as necessary.

[0045] The object to be coated is not particularly limited, and examples thereof include cloth, resin, and metal.

[0046] The method for applying the composition for the coating layer is not particularly limited, and examples thereof include gravure coating, reverse coating, roll coating, bar coating, spray coating, air knife coating, and dipping. The preferred application method is bar coating.

[0047] This produces a coating layer on the surface of the object to be coated.

[0048] In such a coating layer, the moisture absorbing fine particles are dispersed in the matrix resin.

[0049] The coating layer has a thickness at a temperature of 25° C. and a relative humidity of 24%, of, for example, 10 μm to 270 μm, preferably 15 μm to 100 μm, more preferably 20 μm to 80 μm, and still more preferably 30 μm to 50 μm.

[0050] In detail, the thickness of the coating layer is, for example, 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more, from the viewpoint of suppressing roughness due to convex portions derived from moisture-absorbing microparticles (described later), and is 270 μm or less, preferably 100 μm or less, more preferably 50 μm, and even more preferably 40 μm or less, from the viewpoint of reliably forming convex portions derived from moisture-absorbing microparticles (described later).

[0051] In the coating layer, the basis weight of the moisture-absorbing fine particles is, for example, 2.0 g / m from the viewpoint of increasing the number of protrusions (described later) derived from the moisture-absorbing fine particles and changing the tactile feel. 2 More than 5.0 g / m 2 More preferably, 10.0 g / m 2 In addition, from the viewpoint of suppressing the occurrence of roughness due to excessive protrusions (described later) resulting from moisture-absorbing fine particles, for example, 50.0 g / m 2 Less than 15.0 g / m 2 The following is the result.

[0052] The ratio of the average particle size of the moisture-absorbing particles to the thickness of the coating layer is the dynamic friction coefficient F at a relative humidity of 10%. 10 (see below) The coefficient of kinetic friction F at a relative humidity of 90% 90 From the viewpoint of reliably reducing the moisture content (described later), the moisture content is, for example, 0.17 or more, preferably 0.20 or more, more preferably 0.50 or more, even more preferably 0.80 or more, particularly preferably 0.90 or more, and most preferably more than 1.00 or even 1.20. From the viewpoint of suppressing roughness due to convex portions (described later) derived from moisture-absorbing fine particles, the moisture content is, for example, 5.50 or less, preferably 5.00 or less, more preferably 4.00 or less, even more preferably 3.50 or less, particularly preferably 3.00 or less, most preferably 2.00 or less, and even 1.50 or less.

[0053] In addition, this coating layer has a dynamic friction coefficient F at a relative humidity of 10% (low humidity) measured by the following test. 10 and the coefficient of kinetic friction F at a relative humidity of 90% (high humidity) 90 and satisfies the following formula (1). (F 90 / F 10 -1)×100<0 (1)

[0054] The test consisted of first leaving the coating layer at rest for 3 hours under conditions of 25°C and 10% relative humidity (low humidity), and then measuring the dynamic friction coefficient F at 10% relative humidity (low humidity) using a texture evaluation device (sliding speed 10 mm / sec, load 50 gf, sliding distance 10 mm) against the surface of the coating layer. 10 Separately, the coating layer is left to stand for 3 hours under conditions of 25°C and 90% relative humidity (high humidity), and then the dynamic friction coefficient F at 90% relative humidity (high humidity) is measured on the surface of the coating layer using a touch evaluation device (sliding speed 10 mm / sec, load 50 gf, sliding distance 10 mm). 90 Measure.

[0055] If the coating layer satisfies the above formula (1), a desired tactile sensation can be achieved depending on the season.

[0056] On the other hand, if the coating layer does not satisfy the above formula (1), it is not possible to achieve a desired tactile sensation depending on the season.

[0057] (F 90 / F 10 The value of -1) x 100 is preferably -1 or less, more preferably -3 or less, even more preferably -5 or less, particularly preferably -10 or less, and, for example, -30 or more.

[0058] In addition, the maximum peak height Rp of this coating layer at a relative humidity of 10% (low humidity) measured by the second test described below 10 and the maximum peak height Rp at 90% relative humidity (high humidity) 90 and satisfies the following formula (2). 5<(Rp 10 / Rp 90 -1)×100<293 (2)

[0059] The second test is to first leave the coating layer at rest for 3 hours under conditions of 25°C and 10% relative humidity (low humidity), and then measure the maximum peak height Rp of the surface of the coating layer using a one-shot 3D shape measuring device in accordance with JIS B 0601. 10 Separately, the coating layer is left to stand for 3 hours under conditions of 25°C and 90% relative humidity (high humidity), and then the maximum peak height Rp is measured on the surface of the coating layer using a one-shot 3D shape measuring device in accordance with JIS B 0601. 90 Measuring

[0060] If the coating layer satisfies the above formula (2), it is possible to more effectively achieve a desired tactile sensation according to the season.

[0061] The storage modulus (E') of the coat layer at 23°C is, for example, 0.1 MPa or more, preferably 0.3 MPa or more, more preferably 0.5 MPa or more, and even more preferably 1 MPa or more. The storage modulus (E') of the coat layer at 23°C is, for example, 100 MPa or less, preferably 80 MPa or less, more preferably 70 MPa or less, and even more preferably 60 MPa or less.

[0062] The 100% modulus of the coating layer is, for example, 20.0 MPa or less, preferably 17.0 MPa or less, more preferably 15.0 MPa or less. The 100% modulus of the coating layer is, for example, 0.1 MPa or more, preferably 0.3 MPa or more, more preferably 0.5 MPa or more, even more preferably 0.7 MPa or more, and particularly preferably 1.0 MPa or more. The 100% modulus is the stress value at an elongation rate of 100%. In particular, even if the 100% modulus of the coating layer is a relatively high value (for example, exceeding 5.0 MPa), an excellent touch can be obtained as long as the modulus of the surface of the coating layer is within the above range.

[0063] <Action and effect> The coefficient of dynamic friction F at a relative humidity of 10% is measured by the following test. 10 and the coefficient of kinetic friction F at a relative humidity of 90% 90 and satisfies the following formula (1). (F 90 / F 10 -1)×100<0 (1)

[0064] Therefore, it is possible to realize the desired tactile sensation according to the season.

[0065] Specifically, materials are required to have a texture that suits the season: in summer, a dry feel is required, whereas in winter, a moist feel is required.

[0066] However, as shown in Fig. 1A, in winter (low temperature), the material 1 (specifically, the same material as the above-mentioned object to be applied) cools and hardens. Then, the contact area 3 between the material 1 and the finger 2 decreases, and it becomes easy to feel a dry feeling.

[0067] 1B, in summer (high temperature), the material 1 warms up and becomes soft, and the contact area 3 between the material 1 and the finger 2 increases, making it easier to feel a moist sensation.

[0068] In other words, conventional materials tend to provide the opposite feel to the seasonal feel described above, and have the drawback of being unable to provide a seasonal feel.

[0069] On the other hand, when considering the change in the dynamic friction coefficient in Figure 1A and Figure 1B, in Figure 1A, the contact area 3 between material 1 and finger 2 decreases, so the dynamic friction coefficient is low. On the other hand, in Figure 1B, the contact area 3 between material 1 and finger 2 increases, so the dynamic friction coefficient is high.

[0070] This shows that the relationship between the dynamic friction coefficient and the tactile sensation is such that as the dynamic friction coefficient decreases, a smooth feeling is more likely to be felt, and as the dynamic friction coefficient increases, a moist feeling is more likely to be felt.

[0071] In this coating layer, the relationship between the dynamic friction coefficient and the tactile sensation is adjusted to realize a tactile sensation according to the season.

[0072] Specifically, the coating layer has a dynamic friction coefficient F at a relative humidity of 10% (low humidity) measured by the following test. 10 and the coefficient of kinetic friction F at a relative humidity of 90% (high humidity) 90 and satisfies the above formula (1).

[0073] In other words, the coefficient of kinetic friction F at a relative humidity of 90% (high humidity) 90 The coefficient of kinetic friction F at a relative humidity of 10% (low humidity) 10 will be smaller than

[0074] The feel of the coating layer for each season will be described with reference to Figures 2A and 2B. In Figures 2A and 2B, a coating layer 4 is disposed on the surface of the material 1.

[0075] As shown in FIG. 2A, in winter (low humidity), the amount of moisture in the air is low, so the moisture absorption amount of the moisture-absorbing microparticles 5 is low, and the amount of expansion tends to be small. Therefore, the convex parts 6 derived from the moisture-absorbing microparticles 5 (the convex parts 6 formed when the moisture-absorbing microparticles 5 protrude from the surface of the coating layer 4) become smaller. As a result, the contact area 3 between the coating layer 4 and the finger 2 increases, and the dynamic friction coefficient F10 Such a coating layer 4 is more likely to give a moist feeling.

[0076] On the other hand, as shown in FIG. 2B, in summer (high humidity), the moisture content in the air is high, so the moisture absorbing microparticles 5 tend to absorb more water and expand more. This causes the protrusions 6 resulting from the moisture absorbing microparticles 5 to become larger. This reduces the contact area 3 between the coating layer 4 and the finger 2, and the dynamic friction coefficient F 10 Such a coating layer 4 is more likely to give a smooth feel.

[0077] That is, the coating layer can provide a dry feel in summer and a moist feel in winter, i.e., the coating layer can provide a desired tactile feel depending on the humidity (season).

[0078] This coating layer can be used in products that come into direct contact with the skin, including, but not limited to, clothing, furniture, home appliances, daily necessities, public facility equipment, automobile parts, accessories, vehicles, sports, robots, office supplies, architecture, health care, general industrial applications, industrial products, vehicle parts, ships, aircraft materials, machine mechanism parts, civil engineering materials, agricultural materials, and decorative items. Specific examples include linen, clothing, handles, doors, smartphone cases, smartphones, remote controls, earphones, mice, keyboards, headphones, tablet pens, wearable devices (such as VR goggles), game controllers, water bottles, helmets, writing utensils, flooring, doorknobs, toilet seats, chairs (arm rests, control levers, etc.), handrails, automobile interior materials, watches, instrument panels, armrests, door trim, ornaments, steering wheels and other automobile interior materials, toys, canes, umbrellas, desk tops, cooking utensils, cup holders, trays, cosmetic bottles, bags, wallets, business card holders, power tool parts, food containers, film, sheets, fibers, robot skins, and covers for communication devices (tablets, smart watches, etc.). EXAMPLES

[0079] Specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values ​​(numerical values ​​defined as "not more than" or "less than") or lower limit values ​​(numerical values ​​defined as "not less than" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention." In addition, unless otherwise specified in the following description, "parts" and "%" are based on mass.

[0080] <Ingredient details> The product names and abbreviations of the components used in each Example and Comparative Example are described in detail below. Matrix resin: Water dispersion of polyurethane resin containing polycarbonate type water-based polyurethane, Takelac W6110, manufactured by Mitsui Chemicals, Inc. Moisture-absorbing particles: sodium polyacrylate particles, average primary particle diameter 46 μm (temperature 25°C, relative humidity 24%)

[0081] <Production of Coating Layer> Example 1 1.41g (solid content) of Takelac W6110 as a matrix resin, 0.15g of sodium polyacrylate particles as moisture-absorbing fine particles, and 2.94g of water were individually put into a screw tube bottle and stirred with a stirrer tip for 30 minutes. Next, 1cc of this coating layer composition was dropped onto a glass substrate (dimensions 100mm x 200mm x 2mm (thickness)), and the coating layer composition was applied to an area of ​​70mm x 150mm using a bar coater, and dried in a draft at 25°C for 12 hours to obtain a coating layer. The moisture-absorbing fine particle basis weight and thickness of the coating layer (temperature 25°C, relative humidity 24%) are as shown in Table 1. The numerical values ​​of the matrix resin and moisture-absorbing fine particles in Table 1 are the mass (g) of the solid content.

[0082] Examples 2 to 5, Comparative Examples 1 and 2 A coating layer was produced in the same manner as in Example 1, except that the formulation was changed based on the description in Table 1.

[0083] <Evaluation> (Measurement of dynamic friction coefficient) The dynamic friction coefficient F 10 and the coefficient of kinetic friction F 90 was measured.

[0084] Specifically, the coating layer sample and a desiccant (clay desiccant) were placed in a plastic bag, and the coating layer was left to stand for 3 hours under conditions of 25°C and 10% relative humidity. After that, the kinetic friction coefficient F at a relative humidity of 10% was measured for the surface of the coating layer using a tactile evaluation device (dynamic / static friction tester TL201Ts, sliding speed 10 mm / sec, load 50 gf, sliding distance 10 mm). 10 Separately, a tabletop humidifier and a coating layer sample were placed in a 30cm x 30cm x 30cm acrylic box, and the coating layer was left to stand for 3 hours under conditions of 25°C and 90% relative humidity. After that, the dynamic friction coefficient F at 90% relative humidity was measured for the surface of the coating layer using a tactile evaluation device (dynamic / static friction measuring device TL201Ts, sliding speed 10mm / sec, load 50gf, sliding distance 10mm). 90 The results are shown in Table 1. 90 / F 10 The value of −1) × 100 was calculated and is shown in Table 1.

[0085] (Tactile test) The coating layers of each Example and Comparative Example were observed for tactile sensation when rubbed with the pad of an index finger under conditions of 10% relative humidity (low humidity) and 90% relative humidity (high humidity). The tactile sensation was evaluated based on the following criteria. The results are shown in Table 1. The experiment was performed by three people, and the evaluations were consistent. {standard} At 10% relative humidity (low humidity) 〇: I felt a moist feeling. ×: A moist feeling was felt. When the relative humidity is 90% (high humidity) 〇: I felt a smooth texture. ×: No smooth feeling was felt.

[0086] [Table 1] [Explanation of symbols]

[0087] 4 Coating Layer 5 Moisture-absorbing particles

Claims

1. A matrix resin and moisture-absorbing fine particles dispersed in the matrix resin, The coefficient of dynamic friction F at a relative humidity of 10% measured by the following test １０ and the dynamic friction coefficient F at a relative humidity of 90% ９０ and the coating layer satisfies the following formula (1): (F ９０ / F １０ -1)×100<0 (1) Test: The coating layer is left to stand for 3 hours under conditions of 25°C and 10% relative humidity. After that, the surface of the coating layer is subjected to a tactile evaluation using a touch evaluation machine (sliding speed 10 mm / sec, load 50 gf, sliding distance 10 mm) to measure the dynamic friction coefficient F at a relative humidity of 10%. １０ The coating layer is left to stand for 3 hours under conditions of 25°C and 90% relative humidity. After that, the dynamic friction coefficient F at 90% relative humidity is measured on the surface of the coating layer using a touch evaluation machine (sliding speed 10 mm / sec, load 50 gf, sliding distance 10 mm). ９０ Measure.

2. The coating layer according to claim 1 , wherein a ratio of an average particle diameter of the moisture absorbing fine particles to a thickness of the coating layer is 0.20 or more and 5.00 or less.

3. The weight of the moisture-absorbing fine particles is 2.0 g / m ２ Exceeds 50.0 g / m ２ The coating layer according to claim 1 , wherein:

4. The coating layer according to claim 1 , which has a thickness of 10 μm or more and 270 μm or less.

5. The coating layer according to any one of claims 1 to 4, wherein the average particle diameter of the moisture-absorbing fine particles is 31 µm or more and 5000 µm or less.

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