Nonwoven fabrics, filters, prepregs, printed circuit boards, and electronic components

Abstract

To provide a nonwoven fabric excellent in heat resistance, having excellent structural strength even with a small fiber diameter.SOLUTION: A nonwoven fabric of the present disclosure includes fibers including fiber (A) containing a 4-methyl-1-pentene-based polymer (A). The fiber (A) has a difference in glass transition temperature ΔTg measured with a differential scanning calorimeter (DSC) of 4.0°C or more. The fiber has an average fiber diameter of 10 μm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to non-woven fabrics, filters, prepregs, printed wiring boards, and electronic components.

Background Art

[0002] Fibers containing 4-methyl-1-pentene polymers are used in a wide range of applications by taking advantage of their heat resistance and dielectric properties (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Melt-blown non-woven fabrics are excellent in flexibility, uniformity, and density, and further have a fine fiber diameter. The average fiber diameter of the fibers of melt-blown non-woven fabrics is usually 10 μm or less. A single melt-blown non-woven fabric or a non-woven fabric laminate containing a melt-blown non-woven fabric and another non-woven fabric is used in many fields. Specifically, melt-blown non-woven fabrics are used for separation membranes (for example, porous sheets for gas permeable films, etc.), electrolytic capacitor capacitors, separators for polymer batteries, filters, light diffusing materials, liquid absorbers, heat insulating materials, and the like.

[0005] However, melt-blown non-woven fabrics containing 4-methyl-1-pentene polymers tend to be inferior in mechanical properties (for example, structural strength, etc.). Therefore, melt-blown non-woven fabrics containing 4-methyl-1-pentene polymers may have problems in applications where excellent mechanical properties are required.

[0006] For example, bag filters are used to collect high-temperature dust discharged from industrial equipment (e.g., incinerators, coal-fired boilers, metal melting furnaces, etc.). The size of the high-temperature dust particles that pass through a bag filter is relatively large. Therefore, in addition to filtration performance and heat resistance, bag filters sometimes require excellent mechanical properties. Prepregs used in printed circuit boards, like bag filters, sometimes require heat resistance and a certain degree of mechanical properties. Therefore, there is a need for nonwoven fabrics that have excellent heat resistance and excellent structural strength (i.e., tensile strength in the machine direction (MD)) even when the fibers are fine (i.e., when the average fiber diameter is 10 μm or less).

[0007] This disclosure has been made in view of the above-mentioned problems and aims to provide nonwoven fabrics, filters, prepregs, printed circuit boards, and electronic components that have excellent heat resistance and excellent structural strength even with fine fibers. [Means for solving the problem]

[0008] The means for solving the above problems include the following embodiments.

[0009] <1> The material contains fibers containing a 4-methyl-1-pentene polymer (A), The glass transition temperature difference ΔTg of the fiber (A), as measured by a differential scanning calorimeter (DSC), is 4.0°C or higher. A nonwoven fabric in which the average fiber diameter of the aforementioned fibers is 10 μm or less. <2> It is a blended nonwoven fabric, The aforementioned fiber further comprises a fiber (B) containing an amorphous thermoplastic resin (B), The glass transition temperature difference ΔTg of the fiber (B), as measured by a differential scanning calorimeter (DSC), is 0.8°C or greater. <1> The nonwoven fabric described above. <3> The specific surface area is 1.3 m². 2 The above is 1 / g or more <1> or <2> The nonwoven fabric described above. <4> The structural strength is 10 N / 50 mm or more, <1> ~ <3> Nonwoven fabric as described in any one of the following. <5> The aforementioned 4-methyl-1-pentene polymer (A) 90-100 mol% of constituent units derived from 4-methyl-1-pentene, 0 to 10 mole% of constituent units derived from olefins with 2 to 20 carbon atoms other than 4-methyl-1-pentene, Including the above <1> ~ <4> Nonwoven fabric as described in any one of the following. <6> The amorphous thermoplastic resin (B) comprises a cyclic olefin polymer (B-1), The cyclic olefin polymer (B-1) comprises at least one selected from a cyclic olefin copolymer (B-1-1) and a ring-opening polymer of a cyclic olefin (B-1-2). The cyclic olefin copolymer (B-1-1) comprises the following structural unit (a) and the following structural unit (b), <2> The nonwoven fabric described above. Structural unit (a): A structural unit derived from an olefin compound, which is at least one of the following general formulas (I). Structural unit (b): A structural unit derived from a cyclic olefin compound, which is at least one selected from the group consisting of structural units represented by the following general formula (II), structural units represented by the following general formula (III), and structural units represented by the following general formula (IV).

[0010] [ka]

[0011] In the above general formula (I), R 300 This is a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 29 carbon atoms.

[0012] [ka]

[0013] In the general formula (II), u is 0 or 1, v is 0 or a positive integer, and w is 0 or 1. R 61 ~R 78 as well as R a1 and R b1 may be the same as or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. At least two of R 75 ~R 78 may be bonded to each other to form a monocyclic or polycyclic ring.

[0014]

Chemical formula

[0015] In the general formula (III), x and d are each independently 0 or an integer of 1 or more. y and z are each independently an integer of 0 to 2. R 81 ~R 99 may be the same as or different from each other, and are a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an alkoxy group. The carbon atom to which R 89 and R 90 are bonded, and the carbon atom to which R 93 is bonded or the carbon atom to which R 91 is bonded may be bonded directly or via an alkylene group having 1 to 3 carbon atoms. When y = z = 0, R 92 and R 95 or R 95 and R 99 ​​​​​​​​​​​​In the above general formula (IV), R 100 and R 101 These elements may be the same or different from each other, and are hydrogen atoms or hydrocarbon groups having 1 to 5 carbon atoms. f is 1 ≤ f ≤ 18. <7> The cyclic olefin polymer (B-1) includes the cyclic olefin copolymer (B-1-1), <6> The nonwoven fabric described above. <8> The cyclic olefin copolymer (B-1-1) comprises the structural unit (a) and the following structural unit (c), <7> The nonwoven fabric described above. Structural unit (c): A structural unit represented by the general formula (II) above, where u is 0 and v is 1. <9> The glass transition temperature Tg of the fiber (B), as measured by a differential scanning calorimeter (DSC), is 85°C or higher. <2> , and the aforementioned <6> ~ <8> Nonwoven fabric as described in any one of the following. <10> The aforementioned <1> ~ <9> A filter containing a nonwoven fabric as described in any one of the following. <11> The filter is a bug filter, <10> The filters listed below. <12> The aforementioned <1> ~ <9> A nonwoven fabric described in any one of the following, A resin composition comprising at least one of a thermosetting resin and a thermoplastic resin, Prepreg, including <13> The thermosetting resin is a thermosetting resin having a curing temperature that is 20°C or more lower than the lowest melting point of the nonwoven fabric. The thermoplastic resin is a thermoplastic resin having a melting point that is 20°C or more lower than the lowest melting point of the nonwoven fabric. <12> The prepreg described above. <14> The aforementioned <12> The cured or solidified prepreg described above, A conductive layer, which is arranged on one or both sides of the cured or solidified product and has been subjected to wiring processing, A printed circuit board having the following features. <15> An electronic component having a circuit that transmits electrical signals of 1 GHz or higher, The aforementioned <12> An electronic component having an insulating layer containing a cured or solidified prepreg as described above. [Effects of the Invention]

[0018] According to this disclosure, it is possible to provide nonwoven fabrics, filters, prepregs, printed circuit boards, and electronic components that have excellent heat resistance and structural strength even with fine fibers. [Brief explanation of the drawing]

[0019] [Figure 1] Figures 1(a) to 1(i) show examples of spinnerets having a composite spinning nozzle used in a method for manufacturing nonwoven fabrics according to the present disclosure. [Modes for carrying out the invention]

[0020] In this disclosure, the "~" symbol indicating a numerical range is used to mean that the numbers before and after it are included as the lower and upper limits, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. In numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. In this disclosure, the term "process" includes not only independent processes but also any process that cannot be clearly distinguished from other processes, as long as its intended purpose is achieved. In this disclosure, when referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, it means the total amount of all substances present in the composition unless otherwise specified. In this disclosure, “nonwoven fabric” means a planar fiber aggregate obtained by physical and / or chemical methods, excluding weaving, knitting, and papermaking, which provides a predetermined level of structural strength. In this disclosure, "web" refers to a sheet composed solely of fibers. In this disclosure, "split fiber" refers to a fiber that has the property of being split into multiple fibers from a single fiber.

[0021] (1) Nonwoven fabric The nonwoven fabric of this disclosure (hereinafter also simply referred to as "nonwoven fabric") contains fibers (A) containing a 4-methyl-1-pentene polymer (A), and fibers (hereinafter also simply referred to as "fibers"). The glass transition temperature difference ΔTg of the fibers (A), measured by differential scanning calorimeter (DSC), (hereinafter also referred to as "ΔTg(A)") is 4.0°C or higher. The average fiber diameter of the fibers is 10 μm or less.

[0022] In this disclosure, "4-methyl-1-pentene polymer (A)" refers to a polymer whose main component is a structural unit derived from 4-methyl-1-pentene. More specifically, the proportion of structural units derived from 4-methyl-1-pentene is 90 mol% to 100 mol% of the total amount of 4-methyl-1-pentene polymer (A). In this disclosure, "average fiber diameter of the fibers" refers to the average fiber diameter of the fibers constituting the nonwoven fabric of this disclosure. If the fibers include fiber (A) and fiber (B) described later, "average fiber diameter of the fibers" refers to the average fiber diameter of the entire fiber including fiber (A) and fiber (B). The method for measuring the average fiber diameter of the fibers is the same as the method described in the examples.

[0023] In this disclosure, "glass transition temperature difference ΔTg of fiber (A)" refers to the temperature difference between the first glass transition temperature of fiber (A) and the second glass transition temperature of fiber (A). "First glass transition temperature of fiber (A)" refers to the glass transition temperature of fiber (A) measured by the first heating when fiber (A) taken from a nonwoven fabric is melted by first heating at a heating rate of 10°C / min using a differential scanning calorimeter (DSC), then solidified by cooling at a cooling rate of 10°C / min, and then melted by second heating at a heating rate of 10°C / min. "Second glass transition temperature of fiber (A)" refers to the glass transition temperature of fiber (A) measured by the second heating. The method for measuring the glass transition temperature is the same as in the example.

[0024] The fact that the glass transition temperature difference ΔTg of the 4-methyl-1-pentene polymer (A) is 4.0°C or higher indicates that the fiber (A) was manufactured by the spunbond method. The reason for this is as follows: Generally, the glass transition of polymers is explained as relaxation resulting from the microburan motion of amorphous chains. Methods to increase the glass transition temperature include orientation crystallization by stretching and binding between molecular chains. Furthermore, it is known that stretching in the solid state is more suitable than stretching in the molten state for achieving higher molecular orientation. Therefore, it is estimated that the molecular orientation of fibers in nonwoven fabrics obtained by the spunbond method via solid-phase stretching is promoted, and as a result, the glass transition temperature of the fibers is higher than that of the unoriented state. At ΔTg(A), the first glass transition temperature of fiber (A) corresponds to the glass transition temperature of fiber (A) in a state where molecular orientation is promoted, and the second glass transition temperature of fiber (A) corresponds to the glass transition temperature of fiber (A) in an unoriented state. In other words, the first glass transition temperature of fiber (A) is higher than the second glass transition temperature of fiber (A). Furthermore, the glass transition temperature difference ΔTg of fibers manufactured by the meltblown method is typically less than 4.0°C.

[0025] Because the nonwoven fabric of this disclosure has the above-described structure, it has excellent heat resistance and excellent structural strength even with fine fibers. Furthermore, the nonwoven fabric of this disclosure has excellent dielectric properties and heat resistance, as well as excellent filtration performance and structural strength.

[0026] Nonwoven fabrics are sheet-like materials. The structure of a nonwoven fabric is appropriately selected according to its intended use, and may, for example, be a single-layer structure or a multi-layer structure of two or more layers. When the nonwoven fabric is used as a filter or prepreg, a single-layer structure is preferred.

[0027] The nonwoven fabric preferably includes spunbond nonwoven fabric, and more preferably is spunbond nonwoven fabric. The nonwoven fabric may also include other nonwoven fabrics, woven fabrics, knitted fabrics, paper, etc. The other nonwoven fabric may be a short-fiber nonwoven fabric or a long-fiber nonwoven fabric. Examples of other nonwoven fabrics include meltblown nonwoven fabric, wet-laid nonwoven fabric, water-entangled nonwoven fabric, dry-laid nonwoven fabric, dry-laid pulp nonwoven fabric, airlaid nonwoven fabric, flash-spun nonwoven fabric, tow-opened nonwoven fabric, needle-punched nonwoven fabric, and long-fiber cellulose nonwoven fabric.

[0028] The nonwoven fabric of this disclosure is a blended nonwoven fabric, and it is preferable that the fibers further include fibers (B) containing an amorphous thermoplastic resin (B). The glass transition temperature difference ΔTg of the fibers (B) measured by differential scanning calorimeter (DSC) (hereinafter also referred to as "ΔTg(B)") is 0.8°C or higher. Details of the fibers (B) will be described later.

[0029] In this disclosure, "blended nonwoven fabric" refers to a nonwoven fabric in which fibers of different resins are mixed during the spinning stage. In this disclosure, "amorphous thermoplastic resin" refers to a thermoplastic resin that does not have a clear melting point as measured by differential scanning calorimetry (DSC).

[0030] In this disclosure, "glass transition temperature difference ΔTg of fiber (B)" refers to the temperature difference between the first glass transition temperature of fiber (B) and the second glass transition temperature of fiber (B). "First glass transition temperature of fiber (B)" refers to the glass transition temperature of fiber (B) measured by the first heating when fiber (B) taken from a nonwoven fabric is melted by first heating at a heating rate of 10°C / min, then solidified by cooling at a cooling rate of 10°C / min, and then melted by second heating at a heating rate of 10°C / min, using a differential scanning calorimeter (DSC). "Second glass transition temperature of fiber (B)" refers to the glass transition temperature of fiber (B) measured by the second heating. If the nonwoven fabric of this disclosure is a blended nonwoven fabric, the target of measurement for the glass transition temperature difference ΔTg between fiber (A) and fiber (B) may be each of the fibers (A) and fiber (B) separated from the blended nonwoven fabric, or it may be the blended nonwoven fabric itself. The glass transition temperatures Tg of fiber (A) and fiber (B) are different. Therefore, even if the target of measurement is the blended nonwoven fabric itself, the glass transition temperatures Tg of fiber (A) and fiber (B) can be determined from the DSC measurement results of the blended nonwoven fabric itself.

[0031] The nonwoven fabric disclosed herein is a blended nonwoven fabric, and the inclusion of fiber (B) further enhances the filter performance and mechanical properties of the nonwoven fabric. This effect is presumed to be due to, but is not limited to, the following reasons. The blended nonwoven fabric in this disclosure is preferably obtained by producing multiple split fibers by the spunbond method and splitting one split fiber into multiple fibers. Generally, in order to improve the divisibility of split fibers, it is considered necessary that the compatibility between the multiple resins constituting the split fibers is low. In particular, in the case of a combination of a crystalline thermoplastic resin and an amorphous thermoplastic resin, the amorphous thermoplastic resin is easily excluded from the crystalline structure when the crystalline thermoplastic resin crystallizes. Therefore, it is presumed that the compatibility between different resins in the split fibers remains at a macroscopic level. Accordingly, it is presumed that the combination of a crystalline thermoplastic resin such as a 4-methyl-1-pentene polymer (A) and an amorphous thermoplastic resin (B) results in very high divisibility of the split fibers. The high divisibility of split fibers leads to a reduction in the average fiber diameter and improves the filter performance and structural strength of the nonwoven fabric. Specifically, the ease with which split fibers separate means that fewer undivided fibers remain. Therefore, the average fiber diameter of the split fibers becomes smaller. Particle collection occurs when particles adhere to the surface of the fibers that make up the filter. Therefore, an increase in the surface area of ​​the fibers (i.e., fiber fineness) improves the filter performance of the nonwoven fabric. Furthermore, the ease with which split fibers separate means that there are more points of contact between the split fibers. Therefore, the split fibers can bear greater frictional force. As a result, the structural strength of the nonwoven fabric improves. The performance of electronic materials strongly depends on properties such as the dielectric constant and dielectric loss tangent of the resin. In particular, 4-methyl-1-pentene polymers (A) and cyclic olefin polymers (B-1), described later, are known as thermoplastic resins with low dielectric constant and dielectric loss tangent. Therefore, nonwoven fabrics are expected to exhibit excellent electronic material performance.

[0032] The thickness of the nonwoven fabric is not particularly limited and can be appropriately selected according to the intended use of the nonwoven fabric, and may be between 0.05 mm and 100 mm, or between 0.02 mm and 50 mm. The method for measuring the thickness of the nonwoven fabric is the same as that described in the examples.

[0033] The basis weight of the nonwoven fabric is not particularly limited and is selected appropriately according to the intended use of the nonwoven fabric, etc., 1 g / m² 2 ~400g / m 2 It may also be 5g / m 2 ~100g / m 2 That's fine. The method for measuring the basis weight of the nonwoven fabric is the same as that described in the examples.

[0034] The specific surface area of ​​the nonwoven fabric is not particularly limited and is appropriately selected depending on the application of the nonwoven fabric. From the viewpoint of obtaining a nonwoven fabric with excellent filtration performance and structural strength, the specific surface area of ​​the nonwoven fabric is preferably 0.5 m². 2 / g or more, more preferably 0.8m 2 / g or more, more preferably 1.0m 2 / g or more, particularly preferably 1.3m 2 It is 1 / g or more. The specific surface area is, for example, 3.0 m². 2 It may be less than / g. From these viewpoints, the specific surface area of ​​the nonwoven fabric is 0.5m². 2 / g~3.0m 2 / g is also acceptable. The method for measuring the specific surface area of ​​the nonwoven fabric is the same as that described in the examples.

[0035] The structural strength of the nonwoven fabric is not particularly limited and can be appropriately selected depending on the application of the nonwoven fabric, but it is preferably 10 N / 50 mm or more. This makes it possible to apply it to prepregs used in bag filters and printed circuit boards, for example. The structural strength of the nonwoven fabric is more preferably 15N / 50mm or more, even more preferably 20N / 50mm or more, and particularly preferably 25N / 50mm or more, from the viewpoint of application to prepregs used in bag filters and printed circuit boards. The structural strength of the nonwoven fabric may also be, for example, 100N / 50mm or less. From these viewpoints, the structural strength of the nonwoven fabric may be 10N / 50mm to 100N / 50mm. The method for measuring the structural strength of the nonwoven fabric is the same as that described in the examples. Methods for adjusting the structural strength of the nonwoven fabric within the above range include, for example, the type of resin, the shape of the spinneret with a composite spinning nozzle, the fiber molding conditions, or the pressure and number of processing cycles of the high-pressure liquid flow in the splitting process described later. Specifically, the spinning temperature is preferably 260°C to 350°C. The discharge rate per single hole is preferably 0.1 g / min to 5 g / min. The velocity (airflow rate) of the stretching air is 1000 Nm 3 / h / m~50000Nm 3 A value of / h / m is preferable.

[0036] The fabric texture index of the nonwoven fabric is not particularly limited and is appropriately selected according to the intended use of the nonwoven fabric. The fabric texture index of the nonwoven fabric is not particularly limited and may be, for example, between 5 and 300. The method for measuring the fabric density index of the nonwoven fabric is the same as the method described in the examples.

[0037] The quality factor (Q value) of a nonwoven fabric indicates the performance of the nonwoven fabric filter. The Q value of a nonwoven fabric is appropriately selected depending on the application of the nonwoven fabric, for example, from the viewpoint of application to a bag filter, it is preferably 0.08 or higher, more preferably 0.1 or higher, and even more preferably 0.14 or higher. The Q value of a nonwoven fabric is not particularly limited, but is preferably 0.5 or lower, more preferably 0.4 or lower. From these viewpoints, the Q value of a nonwoven fabric may be between 0.08 and 0.5.

[0038] The Q-value of a nonwoven fabric is calculated using the following formula (a) with respect to collection efficiency and pressure loss. As shown in the following formula, the lower the pressure loss and the higher the collection performance, the higher the Q-value, indicating that the filtration performance is good when using nonwoven fabric as a filter. Equation (a): Q value (Pa) -1 ) = -[ln(1-[collection efficiency]) / (pressure loss (Pa))] In equation (a), the collection efficiency represents the collection efficiency of the nonwoven fabric described above, and the pressure drop (Pa) represents the pressure drop of the nonwoven fabric described above.

[0039] The nonwoven fabrics disclosed herein can be used in a wide range of applications in which nonwoven fabrics are typically used. Examples of applications for nonwoven fabrics include filters, sanitary materials, medical components, packaging materials, battery separators, heat-insulating materials, protective clothing, clothing components, electronic materials, sound-absorbing materials, and civil engineering materials.

[0040] Nonwoven fabrics can be preferably used as filters, for example, gas filters (air filters), liquid filters, etc. The nonwoven fabrics of this disclosure are preferably used in high-performance filters with excellent filtration performance. They are useful in the manufacture of bag filters for collecting high-temperature dust (for example, high-temperature dust generated by incinerators, coal-fired boilers, metal melting furnaces, etc.). Nonwoven fabrics are preferable to use as prepregs because they have excellent heat resistance and mechanical properties.

[0041] Nonwoven fabrics may be electrostatically charged depending on their application. Electrostatically charged nonwoven fabrics are suitably used in air filters. Electrostatically charged nonwoven fabrics can be obtained by electrostatically treating nonwoven fabrics.

[0042] (1.1) Fibers The average fiber diameter of the fibers is 10 μm or less. From the viewpoint of obtaining a nonwoven fabric with excellent filtration performance and structural strength, the average fiber diameter of the fibers is preferably 8 μm or less, more preferably 7 μm or less, and even more preferably 6 μm or less. The average fiber diameter of the fibers may be, for example, 1 μm or more, or 2 μm or more. From these viewpoints, the average fiber diameter of the fibers may be between 1 μm and 10 μm. The method for measuring the average fiber diameter of the fibers is the same as the method described in the examples.

[0043] The coefficient of variation (CV) value of the fiber is not particularly limited, but is preferably 70% or less, more preferably 65% ​​or less, and even more preferably 60% or less. The CV value may be 10% or more. The method for measuring the CV value of the fibers is the same as the method described in the examples.

[0044] The fibers may be long fibers or short fibers. The cross-sectional shape of the fibers is not particularly limited and may include, for example, circular, elliptical, or irregularly shaped cross-sections.

[0045] The fibers may be composite fibers or monocomponent fibers. It is preferable that the composite fibers consist of two or more thermoplastic resins. Examples of composite fibers include core-sheath type, side-by-side type, sea-island type, and parallel type.

[0046] (1.1.1) Fibers (A) The fibers include fiber (A).

[0047] ΔTg(A) is 4.0°C or higher. From the viewpoint of obtaining a nonwoven fabric with excellent filtration performance and structural strength, ΔTg(A) is preferably 6.0°C or higher, more preferably 8.0°C or higher, and even more preferably 10°C or higher. ΔTg(A) may be, for example, 20°C or lower, or 18°C ​​or lower. From these viewpoints, ΔTg(A) may be between 4.0°C and 20°C. The method for measuring ΔTg(A) is the same as that described in the examples.

[0048] The average fiber diameter and CV value of fiber (A) should be the same as those of the fiber described above.

[0049] Fiber (A) may be a long fiber or a short fiber. The cross-sectional shape of fiber (A) is not particularly limited and may include, for example, a circular, elliptical, or irregularly shaped cross-section.

[0050] Fiber (A) may be a composite fiber or a monocomponent fiber. The composite fiber preferably consists of two or more thermoplastic resins. Examples of composite fibers include core-sheath type, side-by-side type, sea-island type, and parallel type.

[0051] The content of fiber (A) is appropriately selected according to the intended use of the nonwoven fabric, and may be 10% to 90% by mass, 25% to 75% by mass, or 40% to 60% by mass, relative to the total amount of the nonwoven fabric. The fiber may consist only of fiber (A).

[0052] (1.1.1.1) 4-methyl-1-pentene polymer (A) Fiber (A) contains a 4-methyl-1-pentene polymer (A). Fiber (A) may consist solely of the 4-methyl-1-pentene polymer (A). The melting point of the 4-methyl-1-pentene polymer (A) is typically 200°C or higher. Therefore, the inclusion of the 4-methyl-1-pentene polymer (A) in fiber (A) provides excellent heat resistance to the nonwoven fabric.

[0053] The 4-methyl-1-pentene polymer (A) is either a homopolymer of 4-methyl-1-pentene or a copolymer of 4-methyl-1-pentene and an olefin other than 4-methyl-1-pentene. The copolymer is preferably a random copolymer. From the viewpoint of obtaining a nonwoven fabric with excellent mechanical strength and a small average fiber diameter, the 4-methyl-1-pentene polymer (A) is preferably a homopolymer of 4-methyl-1-pentene.

[0054] The 4-methyl-1-pentene polymer (A) preferably contains 90 mol% to 100 mol% of constituent units derived from 4-methyl-1-pentene and 0 to 10 mol% of constituent units derived from olefins with 2 to 20 carbon atoms other than 4-methyl-1-pentene. This results in superior heat resistance and mechanical properties of the nonwoven fabric. The constituent units derived from 4-methyl-1-pentene are preferably 95 mol% to 100 mol%, and more preferably 97 mol% to 100 mol%, relative to the total amount of constituent units of the 4-methyl-1-pentene polymer (A). The constituent units derived from olefins having 2 to 20 carbon atoms other than 4-methyl-1-pentene are preferably in an amount of 0 mol% to 5 mol%, and more preferably 0 mol% to 3 mol%, relative to the total amount of constituent units of the 4-methyl-1-pentene polymer (A).

[0055] Examples of α-olefins having 2 to 20 carbon atoms that can be copolymerized include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Of the α-olefins having 2 to 20 carbon atoms, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene are particularly preferred. In the above copolymer, not only one of these olefins but two or more may be copolymerized. Furthermore, the 4-methyl-1-pentene and α-olefin used as copolymer raw materials for the 4-methyl-1-pentene polymer (A) may be derived from biomass.

[0056] The 4-methyl-1-pentene polymer (A) can be produced using a stereospecific catalyst. Examples of stereospecific catalysts include magnesium-supported titanium catalysts and metallocene catalysts. The 4-methyl-1-pentene polymer (A) can be obtained by polymerizing or copolymerizing 4-methyl-1-pentene alone or 4-methyl-1-pentene with an olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene, in the presence of a catalyst described in, for example, International Publication WO01 / 53369, International Publication WO01 / 27124, Japanese Patent Application Publication No. 3-193796, or Japanese Patent Application Publication No. 02-41303.

[0057] The 4-methyl-1-pentene polymer (A) may contain known compounding agents (e.g., antioxidants, heat stabilizers, weather stabilizers, etc.) to the extent that they do not impair the purpose of this disclosure. The 4-methyl-1-pentene polymer (A) may be used after being granulated or pulverized by known methods. Examples of granulation or pulverization methods include using a V-blender, ribbon blender, Henschel mixer, or tumbler blender. Another method of granulation or pulverization is to mix the material in the blender and then melt-knead it using an apparatus (e.g., a single-screw extruder, a double-screw extruder, a kneader, a Banbury mixer, etc.).

[0058] To obtain a nonwoven fabric with sufficient mechanical strength and a small average fiber diameter, the melt flow rate (MFR) of the 4-methyl-1-pentene polymer (A) is preferably 100 g / 10 min to 500 g / 10 min, more preferably 200 to 500 g / 10 min. The measurement conditions for the melt flow rate (MFR) are 260°C and 5 kg load, in accordance with ASTM D1238. The MFR of the 4-methyl-1-pentene polymer (A) can be controlled by supplying hydrogen to the polymerization reaction system during polymerization, thereby increasing the MFR value of the resulting 4-methyl-1-pentene polymer (A). The MFR value of the 4-methyl-1-pentene polymer (A) obtained by the polymerization reaction can be further increased by melt kneading, or by adding peroxides and melt kneading, and the MFR value can be controlled by appropriately combining these methods.

[0059] The molecular weight distribution (Mw / Mn) of the 4-methyl-1-pentene polymer (A) is preferably 2 to 10, more preferably 2 to 8, and even more preferably 2 to 5. The molecular weight distribution (Mw / Mn) of the 4-methyl-1-pentene polymer (A) is determined from the molecular weight (weight-average molecular weight Mw, number-average molecular weight Mn) obtained by calibration using a polystyrene standard with gel permeation chromatography (GPC) (Waters Alliance 2000 type), using a Tosoh Corporation (GMH type) column and o-dichlorobenzene as the mobile phase. The Mw / Mn of the 4-methyl-1-pentene polymer (A) can be controlled by the type of polymerization catalyst used, polymerization conditions, etc. In particular, by using a metallocene catalyst, it is possible to obtain a 4-methyl-1-pentene polymer (A) with a narrow Mw / Mn.

[0060] When the MFR and Mw / Mn of the 4-methyl-1-pentene polymer (A) are within the above range, excessive heating is not required to lower the melt viscosity of the 4-methyl-1-pentene polymer (A) when spinning the fiber (A). This improves productivity reductions caused by clogging of the spinning nozzle, yarn breakage, and generation of foreign matter (e.g., charring) due to thermal decomposition of the polymer, and allows for a wider range of operating conditions during spinning. Furthermore, since fluctuations in melt viscosity can be suppressed, fibers with a uniform average fiber diameter can be obtained.

[0061] The crystallization temperature (Tc) of the 4-methyl-1-pentene polymer (A) is preferably 200°C to 225°C, more preferably 210°C to 225°C. When the crystallization temperature (Tc) of the 4-methyl-1-pentene polymer (A) is 200°C to 225°C, the processability of the nonwoven fabric is excellent. The crystallization temperature (Tc) of the 4-methyl-1-pentene polymer (A) is measured using a differential scanning calorimeter (DSC) after heating the 4-methyl-1-pentene polymer (A) in air to 300°C, holding it for 5 minutes, and cooling it at a rate of 20°C / min.

[0062] The melting point (Tm) of the 4-methyl-1-pentene polymer (A) is preferably 210°C to 245°C, more preferably 230°C to 245°C. The melting point (Tm) of the 4-methyl-1-pentene polymer (A) is measured using a differential scanning calorimeter (DSC) in air at a heating rate of 20°C / min.

[0063] (1.1.2) Fibers (B) The fiber may further contain fiber (B) in addition to fiber (A).

[0064] From the viewpoint of obtaining a nonwoven fabric with excellent filtration performance and structural strength, ΔTg(B) is preferably 0.8°C or higher, more preferably 1.0°C or higher, even more preferably 1.2°C or higher, and particularly preferably 1.45°C or higher. ΔTg(B) may also be, for example, 5.0°C or lower. From these viewpoints, ΔTg(B) may be between 0.8°C and 5.0°C. The method for measuring ΔTg(B) is the same as that described in the examples.

[0065] The glass transition temperature (Tg) of fiber (B) is preferably 85°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, particularly preferably 110°C or higher, and even more preferably 125°C or higher, from the viewpoint of reducing variation in average fiber diameter and heat resistance. The glass transition temperature (Tg) of fiber (B) is preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower, from the viewpoint of excellent spinning stability. The glass transition temperature (Tg) of fiber (B) is preferably 85°C to 170°C, more preferably 90°C to 170°C, even more preferably 100°C to 160°C, particularly preferably 110°C to 150°C, and even more preferably 125°C to 150°C. The method for measuring ΔTg(B) is the same as that described in the examples.

[0066] The average fiber diameter and CV value of fiber (B) should be the same as those of the fiber described above.

[0067] Fiber (B) may be a long fiber or a short fiber. The cross-sectional shape of fiber (B) is not particularly limited and may include, for example, a circular, elliptical, or irregularly shaped cross-section.

[0068] Fiber (B) may be a composite fiber or a monocomponent fiber. The composite fiber preferably consists of two or more thermoplastic resins. Examples of composite fibers include core-sheath type, side-by-side type, sea-island type, and parallel type.

[0069] If the fiber further contains fiber (B), the content ratio of fiber (A) and the content ratio of fiber (B) are preferably within the following ranges. The ratio of resin composition A constituting fiber (A) to resin composition B constituting fiber B (resin composition A:resin composition B) is not particularly limited, but is preferably 90:10 to 90:10 by mass ratio, more preferably 70:30 to 30:70, and even more preferably 50:50.

[0070] (1.1.2.1) Amorphous thermoplastic resin (B) The fiber (B) contains an amorphous thermoplastic resin (B). The fiber (B) may consist solely of the amorphous thermoplastic resin (B).

[0071] Examples of amorphous thermoplastic resins (B) include cyclic olefin polymers (B-1), polycarbonates, polyarylates which are copolymers of bisphenol A and terephthalic acid, polyphenylene ethers, modified polyphenylene ethers which are polymer alloys of polyphenylene ether and polystyrene (including high-impact polystyrene), polyvinyl chloride, polyphenylene sulfide, polyethersulfone, polyamide-imide, polyetherimide, and polyester carbonate. Among these, from the viewpoint of achieving both excellent filter performance and structural strength, as well as a low average fiber diameter, the amorphous thermoplastic resin (B) preferably contains a cyclic olefin polymer (B-1), and is more preferably a cyclic olefin polymer (B-1).

[0072] (1.1.2.2) Cyclic olefin polymer (B-1) The cyclic olefin polymer (B-1) is not particularly limited as long as it is a polymer containing structural units derived from a cyclic olefin compound.

[0073] The fibers contained in the nonwoven fabric may contain only a cyclic olefin polymer (B-1) as the resin, or they may contain a cyclic olefin polymer (B-1) and other resins. Examples of other resins include thermoplastic resins.

[0074] From the viewpoint of heat resistance, the content of the cyclic olefin polymer (B-1) is preferably 50% by mass or more, more preferably 90% by mass or more, and even more preferably 99% by mass or more, relative to the total amount of resin. The content of the cyclic olefin polymer (B-1) may be 100% by mass relative to the total amount of fiber.

[0075] The thermoplastic resin that may be included in fiber (B) is not particularly limited and includes homopolymers or copolymers of α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, and 4-methyl-1-hexene; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon-6, nylon-66, and polymetaxylene adipamide; polyvinyl chloride; polyimide; ethylene-vinyl acetate copolymer; polyacrylonitrile; polycarbonate; polystyrene; and ionomers. The thermoplastic resin may consist of one type or a mixture of two or more types.

[0076] Examples of α-olefin homopolymers or copolymers include ethylene-based polymers such as ethylene-propylene random copolymer, high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene, and ethylene-1-butene random copolymer; propylene-based polymers such as polypropylene (propylene homopolymer), propylene-ethylene random copolymer, and propylene-1-butene random copolymer; and poly-1-butene and poly-4-methyl-1-pentene.

[0077] The amorphous thermoplastic resin (B) contains a cyclic olefin polymer (B-1), and the cyclic olefin polymer (B-1) contains at least one selected from a cyclic olefin copolymer (B-1-1) and a ring-opening polymer of a cyclic olefin compound (B-1-2). The cyclic olefin copolymer (B-1-1) preferably contains the following structural unit (a) and the following structural unit (b), and more preferably contains the cyclic olefin copolymer (B-1-1). As a result, the nonwoven fabric has superior filtration performance and mechanical properties. Details of structural unit (a) and structural unit (b) will be described later.

[0078] (1.1.2.3) Cyclic olefin copolymer (B-1-1) A cyclic olefin copolymer (B-1-1) is a copolymer containing structural units derived from a cyclic olefin compound and structural units derived from a compound other than a cyclic olefin compound. Preferably, a cyclic olefin copolymer (B-1-1) is a copolymer containing at least one structural unit selected from the group consisting of structural units derived from ethylene and structural units derived from α-olefins, and structural units derived from a cyclic olefin compound. More preferably, a cyclic olefin copolymer (B-1-1) is a copolymer containing structural units derived from ethylene or α-olefins, and structural units derived from a cyclic olefin compound.

[0079] The cyclic olefin compound constituting the cyclic olefin copolymer (B-1-1) is not particularly limited, and examples include the cyclic olefin monomers described in paragraphs 0037 to 0063 of International Publication No. 2006 / 118261.

[0080] From the viewpoint of obtaining a nonwoven fabric with low fiber diameter variation and low average fiber diameter, the cyclic olefin copolymer (B-1-1) preferably contains structural unit (a) and structural unit (b). Structural unit (a): A structural unit derived from an olefin compound, which is at least one of the following general formulas (I). Structural unit (b): A structural unit derived from a cyclic olefin compound, which is at least one selected from the group consisting of structural units represented by the following general formula (II), structural units represented by the following general formula (III), and structural units represented by the following general formula (IV).

[0081] [ka]

[0082] In the above general formula (I), R 300 This is a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 29 carbon atoms.

[0083] [ka]

[0084] In the general formula (II) above, u is 0 or 1, v is 0 or a positive integer, and w is 0 or 1. 61 ~R 78 R a1 and R b1 These may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkyl halide having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. 75 ~R 78 At least two of these may be joined together to form a monoring or polyring. v is preferably an integer between 0 and 2, more preferably 0 or 1.

[0085] [ka]

[0086] In the general formula (III) above, x and d are each independent integers of 0 or greater than or equal to 1. y and z are each independent integers between 0 and 2. 81 ~R 99 These may be the same or different from each other, and are a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an alkoxy group. 89 and R 90 The carbon atom to which it is bonded, and R 93 The carbon atom or R to which it is bonded 91 The carbon atoms to which it is bonded may be directly bonded or via an alkylene group having 1 to 3 carbon atoms. When y=z=0, R 92 and R 95 or R 95 and R 99These elements may be bonded to each other to form a monocyclic or polycyclic aromatic ring. x and d are each independently preferably integers between 0 and 2, more preferably 0 or 1.

[0087] [ka]

[0088] In the above general formula (IV), R 100 , R 101 These elements may be identical or different, and represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms. f is 1 ≤ f ≤ 18.

[0089] From the viewpoint of obtaining a nonwoven fabric with excellent filter performance, the cyclic olefin polymer (B-1) preferably contains a cyclic olefin copolymer (B-1-1). The cyclic olefin polymer (B-1) consists of the aforementioned structural unit (a) and the aforementioned structural unit (b), and it is more preferable that the aforementioned structural unit (b) includes the structural unit represented by the aforementioned general formula (II). The cyclic olefin polymer (B-1) is more preferably composed of the aforementioned structural unit (a) and the following structural unit (c). It is particularly preferable that the cyclic olefin polymer (B-1) consists only of the aforementioned structural unit (a) and the following structural unit (c). Structural unit (c): A structural unit represented by the general formula (II) above, where u is 0 and v is 1.

[0090] The olefin compound, which is one of the copolymerization raw materials for cyclic olefin copolymers (B-1-1), is a compound that forms a structural unit represented by the above general formula (I) through addition polymerization. Specifically, the olefin compound represented by the following general formula (Ia), which corresponds to the above general formula (I), is used.

[0091] [ka]

[0092] In the above general formula (Ia), R 300 This refers to a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms.

[0093] Examples of olefin compounds represented by the above general formula (Ia) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. From the viewpoint of obtaining better heat resistance and mechanical properties, among these, ethylene and propylene are preferred as olefin compounds, and ethylene is more preferred. The olefin compound represented by the above general formula (Ia) may be used alone or in combination of two or more.

[0094] When the total structural units constituting the cyclic olefin copolymer (B-1-1) are considered to be 100 mol%, the proportion of structural units (a) derived from the olefin compound is preferably 5 mol% to 95 mol%, more preferably 20 mol% to 90 mol%, even more preferably 40 mol% to 80 mol%, and particularly preferably 50 mol% to 70 mol%. The proportion of structural units (a) derived from olefin compounds can be measured by 13C-NMR.

[0095] Examples of cyclic olefin compounds that are copolymerization raw materials for cyclic olefin copolymers (B-1-1) include cyclic olefin monomers represented by general formula (IIa), cyclic olefin monomers represented by general formula (IIIa), and cyclic olefin monomers represented by general formula (IVa), which correspond to the structural unit represented by general formula (II), the structural unit represented by general formula (III), and the structural unit represented by general formula (IV), respectively.

[0096] [ka]

[0097] In the above general formula (IIa), u is 0 or 1, v is 0 or a positive integer, preferably an integer between 0 and 2, more preferably 0 or 1, w is 0 or 1, R 61 ~R 78 R a1 and R b1 These may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkyl halide having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms, R 75 ~R 78 At least two of these may be bonded to each other to form a monocycle or polycycle.

[0098] From the viewpoint of obtaining a nonwoven fabric with low fiber diameter variation and low average fiber diameter, it is preferable that the cyclic olefin compound, which is one of the copolymerization raw materials for the cyclic olefin copolymer (B-1-1), forms a structural unit represented by the above general formula (II) by addition polymerization. Specifically, it is preferable to use a cyclic olefin monomer represented by general formula (IIa), which corresponds to the above general formula (II).

[0099] As copolymerization raw materials for the cyclic olefin copolymer (B-1-1), it is preferable to use only olefin compounds represented by general formula (Ia) and cyclic olefin compounds represented by general formula (IIa). From the viewpoint of obtaining a nonwoven fabric with excellent filter performance, it is even more preferable to use only olefin compounds represented by general formula (Ia) and cyclic olefin compounds represented by general formula (IIa) where u is 0 and v is 1.

[0100] [ka]

[0101] In the above general formula (IIIa), x and d are each an independent integer of 0 or 1 or more, preferably an integer between 0 and 2, more preferably 0 or 1, and y and z are each an independent integer of 0, 1 or 2, R 81 ~R 99 These may be the same or different from each other, and are a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group which is an aromatic hydrocarbon group which is a 6 to 20 carbon atom or an alkoxy group, R 89 and R 90 The carbon atom to which it is bonded, and R 93 The carbon atom or R to which it is bonded 91 The carbon atom to which it is bonded may be directly bonded or bonded via an alkylene group having 1 to 3 carbon atoms, and when y=z=0, R 95 and R 92 or R 95 and R 99 These elements may be bonded to each other to form a monocyclic or polycyclic aromatic ring.

[0102] [ka]

[0103] In the above general formula (IVa), R 100 and R 101 These elements may be the same or different from each other, and are hydrogen atoms or hydrocarbon groups having 1 to 5 carbon atoms, where f is 1 ≤ f ≤ 18.

[0104] It is preferable to use the olefin compound represented by the general formula (Ia) described above, along with a cyclic olefin monomer represented by the general formula (IIa), a cyclic olefin monomer represented by the general formula (IIIa), or a cyclic olefin monomer represented by the general formula (IVa) as copolymerization components. This further improves the solubility of the cyclic olefin copolymer (B-1-1) in the solvent, resulting in good moldability.

[0105] Specific examples of cyclic olefin monomers represented by general formula (IIa), cyclic olefin monomers represented by general formula (IIIa), and cyclic olefin monomers represented by general formula (IVa) include the compounds described in paragraphs 0037 to 0063 of International Publication No. 2006 / 118261. Specifically, these include bicyclo-2-heptene derivatives (bicyclohept-2-ene derivatives), tricyclo-3-decene derivatives, tricyclo-3-undecene derivatives, tetracyclo-3-dodecene derivatives, pentacyclo-4-pentadecene derivatives, pentacyclopentadecadiene derivatives, pentacyclo-3-pentadecene derivatives, pentacyclo-4-hexadecene derivatives, pentacyclo-3-hexadecene derivatives, hexacyclo-4-heptadecene derivatives, and heptacyclo-5-eicosene. Examples include derivatives, heptacyclo-4-eicosene derivatives, heptacyclo-5-heneicosene derivatives, octacyclo-5-docosene derivatives, nonacyclo-5-pentacosene derivatives, nonacyclo-6-hexacosene derivatives, cyclopentadiene-acenaphthylene adducts, 1,4-methano-1,4,4a,9a-tetrahydrofluorene derivatives, 1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene derivatives, and cycloalkylene derivatives having 3 to 20 carbon atoms.

[0106] Among the cyclic olefin monomers represented by general formula (IIa), cyclic olefin monomers represented by general formula (IIIa), and cyclic olefin monomers represented by general formula (IVa), the cyclic olefin monomer represented by general formula (IIa) is preferred.

[0107] As the cyclic olefin monomer represented by the above general formula (IIa), it is preferable to use bicyclo[2.2.1]-2-heptene (also called norbornene) or tetracyclo[4.4.0.12,5.17,10]-3-dodecene (also called tetracyclododecene), and it is more preferable to use tetracyclo[4.4.0.12,5.17,10]-3-dodecene. These cyclic olefin monomers have the advantage that the elastic modulus of the copolymer is easily maintained because they contain a rigid ring structure.

[0108] When the total amount of structural units constituting the cyclic olefin copolymer (B-1-1) is considered to be 100 mol%, the proportion of structural unit (b) is preferably 5 mol% to 95 mol%, more preferably 10 mol% to 80 mol%, even more preferably 20 mol% to 60 mol%, and particularly preferably 30 mol% to 50 mol%. The proportion of structural unit (b) can be measured by 13C-NMR.

[0109] The type of copolymerization of the cyclic olefin copolymer (B-1-1) is not particularly limited, and examples include random copolymers and block copolymers. In this disclosure, from the viewpoint of obtaining optical components with excellent optical properties such as transparency, refractive index and birefringence, and high precision, it is preferable to use a random copolymer as the cyclic olefin copolymer (A-1).

[0110] The cyclic olefin copolymer (B-1-1) is preferably a random copolymer of ethylene and tetracyclo[4.4.0.12,5.17,10]-3-dodecene, and preferably a random copolymer of ethylene and bicyclo[2.2.1]-2-heptene, with the random copolymer of ethylene and tetracyclo[4.4.0.12,5.17,10]-3-dodecene being more preferred.

[0111] The cyclic olefin copolymer (B-1-1) may be used alone or in combination of two or more types. Furthermore, the monomers used as copolymerization raw materials for the cyclic olefin copolymer (B-1-1) may be derived from biomass.

[0112] The cyclic olefin copolymer (B-1-1) can be manufactured by selecting appropriate conditions according to the methods described in, for example, Japanese Patent Publication No. 60-168708, Japanese Patent Publication No. 61-120816, Japanese Patent Publication No. 61-115912, Japanese Patent Publication No. 61-115916, Japanese Patent Publication No. 61-271308, Japanese Patent Publication No. 61-272216, Japanese Patent Publication No. 62-252406, and Japanese Patent Publication No. 62-252407.

[0113] The content of the cyclic olefin copolymer (B-1-1) is preferably 80% to 100% by mass, more preferably 80% to 99% by mass, even more preferably 90% to 99% by mass, and particularly preferably 95% to 99% by mass, relative to the total amount of fibers contained in the nonwoven fabric.

[0114] The glass transition temperature (Tg) of the cyclic olefin copolymer (B-1-1) is preferably 85°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, particularly preferably 110°C or higher, and even more preferably 125°C or higher, from the viewpoint of reducing the variation in average fiber diameter and heat resistance. The glass transition temperature (Tg) of the cyclic olefin copolymer (B-1-1) is preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower, from the viewpoint of excellent spinning stability. The glass transition temperature (Tg) of the cyclic olefin copolymer (B-1-1) is preferably 85°C to 170°C, more preferably 90°C to 170°C, even more preferably 100°C to 160°C, particularly preferably 110°C to 150°C, and even more preferably 125°C to 150°C. The glass transition temperature (Tg) of a cyclic olefin copolymer (B-1-1) can be measured using a differential scanning calorimetry (DSC). For example, using an RDC220 manufactured by SII Nanotechnology, the glass transition temperature can be measured when the temperature is raised from room temperature to 200°C at a rate of 10°C / min under a nitrogen atmosphere, held for 5 minutes, then cooled to 30°C at a rate of 10°C / min, held for 5 minutes, and then raised to 200°C at a rate of 10°C / min. When measuring the glass transition temperature of a cyclic olefin copolymer (B-1-1) using a nonwoven fabric, the glass transition temperature may be measured after melting the nonwoven fabric into a resin mass. If multiple glass transition temperatures are observed, the effects of this disclosure are preferably achieved if at least one of them satisfies the aforementioned numerical range of glass transition temperatures.

[0115] (1.1.2.4) Ring-opening polymers of cyclic olefins (B-1-2) The cyclic olefin polymer (B-1) may be a ring-opened polymer of a cyclic olefin (B-1-2). Examples of ring-opened polymers of cyclic olefins (B-1-2) include ring-opened polymers of norbornene monomers, ring-opened polymers of norbornene monomers and other monomers copolymerizable with them, and their hydrides.

[0116] Examples of norbornene monomers include bicyclo[2.2.1]hepto-2-ene (also known as norbornene) and its derivatives (those containing substituents on the ring), tricyclo[4.3.01,6.12,5]deca-3,7-diene (also known as dicyclopentadiene) and its derivatives, 7,8-benzotricyclo[4.3.0.12,5]deca-3-ene (methanotetrahydrofluorene: also known as 1,4-methano-1,4,4a,9a-tetrahydrofluorene) and its derivatives, tetracyclo[4.4.0.12,5.17,10]-3-dodecene (also known as tetracyclododecene) and its derivatives, and the like.

[0117] Substituents that can be substituted on the rings of these derivatives include alkyl groups, alkylene groups, vinyl groups, alkoxycarbonyl groups, alkylidene groups, and the like. There may be one or more substituents. Examples of derivatives containing substituents on such rings include 8-methoxycarbonyl-tetracyclo[4.4.0.12,5.17,10]dodeca-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo[4.4.0.12,5.17,10]dodeca-3-ene, and 8-ethylidene-tetracyclo[4.4.0.12,5.17,10]dodeca-3-ene.

[0118] These norbornene monomers can be used individually or in combination of two or more. Ring-opening polymers of norbornene monomers, or ring-opening polymers of norbornene monomers and other monomers copolymerizable thereto, can be obtained by polymerizing the monomer components in the presence of a known ring-opening polymerization catalyst.

[0119] Examples of ring-opening polymerization catalysts that can be used include catalysts comprising a metal halide such as ruthenium or osmium, a nitrate or acetylacetone compound, and a reducing agent; catalysts comprising a metal halide or acetylacetone compound such as titanium, zirconium, tungsten, or molybdenum, and an organoaluminum compound; and others. Examples of other monomers that can be ring-opening copolymerized with norbornene monomers include monocyclic cyclic olefin monomers such as cyclohexene, cycloheptene, and cyclooctene.

[0120] Hydrogenates of ring-opening polymers of norbornene monomers, and hydrides of ring-opening polymers of norbornene monomers and other monomers copolymerizable thereto, can usually be obtained by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to the polymerization solution of the ring-opening polymer and hydrogenating the carbon-carbon unsaturated bond.

[0121] The ring-opening polymer of the cyclic olefin (B-1-2) may be used alone or in combination of two or more types.

[0122] The ring-opening polymer (B-1-2) of the cyclic olefin can be produced by selecting appropriate conditions according to the methods described in, for example, Japanese Patent Publication No. 60-26024, Japanese Patent Publication No. 9-268250, Japanese Patent Publication No. 63-145324, and Japanese Patent Publication No. 2001-72839.

[0123] (1.1.3) Additives The fibers contained in the nonwoven fabric may, if necessary, contain commonly used additives. Examples of additives include various known additives such as antioxidants, weather stabilizers, heat stabilizers, light stabilizers, antistatic agents, antifogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, and waxes. From the viewpoint of reducing the variation in average fiber diameter and minimizing the average fiber diameter, it is preferable that the fibers contained in the nonwoven fabric include antioxidants and lubricants.

[0124] Examples of methods for kneading a cyclic olefin polymer (B-1) and an additive are given. When the cyclic olefin polymer (B-1) and the additive each have either a melting point or a glass transition temperature, known methods include mixing them in a mixer tumbler or the like at a temperature below their respective melting points or glass transition temperatures, and then supplying the mixture to the hopper of a molding machine; supplying the cyclic olefin polymer (B-1) and the additive to an extruder while mixing them using a mixing feeder or the like; and side-feeding to an extruder hopper or the like.

[0125] (1.1.3.1) Antioxidants As antioxidants, phenol-based antioxidants, phosphorus-based stabilizers, sulfur-based stabilizers, and ultraviolet absorbers have antioxidant activity against heated and melted cyclic olefin polymers (B-1).

[0126] Examples of antioxidants include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Examples of phenol-based antioxidants include octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Examples of phosphorus-based antioxidants include triphenyl phosphite, tris(cyclohexylphenyl) phosphite, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene. Examples of sulfur-based antioxidants include dimyristyl 3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, laurylstearyl-3,3'-thiodipropionate, and pentaerythritol-tetrakis(β-lauryl-thiopropionate). These antioxidants can be used individually or in combination of two or more. Among these, it is preferable that a phenol-based antioxidant is included.

[0127] In the fibers contained in the nonwoven fabric, the antioxidant content is preferably 0.01 to 0.4 parts by mass, more preferably 0.02 to 0.3 parts by mass, even more preferably 0.02 to 0.2 parts by mass, particularly preferably 0.02 to 0.1 parts by mass, and even more preferably 0.02 to 0.08 parts by mass, per 100 parts by mass of the cyclic olefin polymer (B-1). A content of 0.01 parts by mass or more of antioxidants tends to suppress the occurrence of burning in molded products. When the antioxidant content is 0.4 parts by mass or less, it tends to suppress the reduction in the blocking rate of fine particles and the leaching of antioxidants from the molded product.

[0128] (1.1.3.2) Lubricants The lubricant preferably contains functional groups such as hydroxyl groups, carboxyl groups, oxyalkylene groups, ester groups, amino groups, amide groups, sulfo groups, epoxy groups, acid anhydride groups, metal acid salts, phosphono groups, phosphino groups, and silyl groups. When a lubricant containing the aforementioned functional groups is used in combination with a cyclic olefin polymer (B-1), the lubricant begins to dissolve before the cyclic olefin polymer (B-1) during molding, thereby suppressing the pressure and shear force applied to the cyclic olefin polymer (B-1). As a result, variations in the average fiber diameter during spinning tend to be effectively suppressed.

[0129] The lubricant may contain two or more functional groups. If the lubricant contains two or more functional groups, they may contain different types of functional groups or the same type of functional group. The lubricant may be a compound having a structure in which at least one of the aforementioned functional groups is bonded to a carbon atom of a linear hydrocarbon group, or a compound having a structure in which the aforementioned functional group is bonded to a carbon atom of a linear hydrocarbon group and at least one other carbon atom of the linear hydrocarbon group is bonded to the aforementioned functional group. Among the functional groups, amide groups and silyl groups are preferred, and amide groups are more preferred.

[0130] Examples of lubricants include fatty acid amides, fatty acid metal salts, and silicone compounds. Examples of fatty acid amides include fatty acid monoamides, fatty acid diamides, saturated fatty acid monoamides, and unsaturated fatty acid diamides. Specific examples of fatty acid amides include lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, montanic acid amide, methylenebislauric acid amide, methylenebismyristic acid amide, methylenebispalmitic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide, methylenebisbehenic acid amide, methylenebisoleic acid amide, methylenebiserucic acid amide, ethylenebisoleic acid amide, and ethylenebiserucic acid amide. Examples of fatty acid metal salts include zinc stearate, calcium stearate, magnesium stearate, lithium stearate, sodium stearate, calcium 12-hydroxystearate, zinc 12-hydroxystearate, sodium 12-hydroxystearate, zinc montanate, and sodium montanate. Examples of silicone-based compounds include alkyl silicon alkoxides such as methyltrimethoxysilane and dimethyldimethoxysilane, and silylated polyolefins. As for silylated polyolefins, any compound containing both a silicone portion and a polyolefin portion is acceptable. For example, compounds described in paragraphs 0025 to 0032 of Japanese Patent Application Publication No. 2017-39892 can be used.

[0131] In the fibers contained in the nonwoven fabric, the lubricant content is preferably 0.005 to 0.4 parts by mass, more preferably 0.01 to 0.4 parts by mass, even more preferably 0.02 to 0.3 parts by mass, particularly preferably 0.02 to 0.2 parts by mass, and even more preferably 0.02 to 0.1 parts by mass, per 100 parts by mass of the cyclic olefin polymer (B-1). When the lubricant content is 0.01 parts by mass or more, variations in average fiber diameter tend to be more effectively suppressed. When the lubricant content is 0.4 parts by mass or less, it tends to suppress the reduction in the effectiveness of blocking fine particles and the leaching of lubricant from the molded product.

[0132] By combining the cyclic olefin polymer (B-1) with an antioxidant and a lubricant, spinning stability is further improved, and the variation in average fiber diameter and the average fiber diameter itself can be suitably reduced. In particular, the effects of the present invention are more favorably achieved by setting the antioxidant content to 0.01 to 0.4 parts by mass per 100 parts by mass of the cyclic olefin polymer (B-1), and the lubricant content to 0.005 to 0.4 parts by mass per 100 parts by mass of the cyclic olefin polymer (B-1). The content of the antioxidant and lubricant may be appropriately combined within the above numerical ranges.

[0133] (2) Filter The filter of this disclosure includes the nonwoven fabric of this disclosure. As a result, the filter of this disclosure has excellent heat resistance, filtration performance and structural strength.

[0134] Examples of filters include bag filters, dust collection filters, air cleaners, hollow fiber filters, and water purification filters. Among these, bag filters are preferred because nonwoven fabrics have excellent heat resistance.

[0135] The filter structure may be appropriately selected depending on the application of the filter, and may be a single-layer structure or a multi-layer structure of two or more layers. If the filter structure is a multi-layer structure, the filter may include multiple nonwoven fabrics of the present disclosure.

[0136] (3) Prepreg The prepreg of the present disclosure comprises the nonwoven fabric of the present disclosure and a resin composition comprising at least one of a thermosetting resin and a thermoplastic resin. Because the prepreg of the present disclosure includes the nonwoven fabric of the present disclosure, it exhibits excellent heat resistance when the resin composition is cured or solidified.

[0137] From the viewpoint of providing a prepreg with superior heat resistance when cured or solidified, the thermal expansion coefficient of the cured product obtained by heating at 145°C for 10 minutes or the solidified product obtained by cooling at room temperature (23°C) is preferably 50 ppm / °C or less, more preferably 40 ppm / °C or less.

[0138] From the viewpoint of providing superior performance when used as an insulating layer in a printed circuit board as described later, the prepreg of this disclosure has a dielectric loss tangent value at 1 GHz when cured, preferably 0.005 or less, and more preferably 0.001 or less. The methods used to bring the dielectric loss tangent value within the above range are not particularly limited and include, for example, methods to reduce the moisture content; methods to reduce the fiber diameter; etc.

[0139] The method for manufacturing the prepreg is not particularly limited, and known manufacturing methods can be applied. For example, a method for manufacturing the prepreg includes the steps of impregnating a nonwoven fabric of the present disclosure with a varnish containing a resin composition to obtain an impregnated body, and heating the obtained impregnated body to remove the solvent contained in the varnish and drying it.

[0140] Impregnation of a nonwoven fabric of the present disclosure with the above-mentioned resin composition of varnish can be carried out, for example, by applying a predetermined amount of varnish to the nonwoven fabric of the present disclosure, and if necessary, further applying a protective film on top of it, and pressing it from above with a roller or the like. Examples of application methods include spray coating, dip coating, roll coating, curtain coating, die coating, and slit coating.

[0141] The method for heating the impregnated body and drying the solvent contained in the varnish is not particularly limited and includes, for example, a batch drying method using a forced-air dryer under an atmospheric or nitrogen atmosphere, or a continuous drying method using a heating furnace.

[0142] Examples of thermosetting resins include epoxy resins, melamine resins, phenolic resins, unsaturated polyester resins, and silicone resins. Among these, it is preferable that the thermosetting resin includes epoxy resin. The thermosetting resin may be a single type or a combination of two or more types. From the viewpoint of producing a prepreg with excellent heat resistance when cured, it is preferable that the curing resin is a thermosetting resin having a curing temperature at least 20°C lower than the lowest melting point of the nonwoven fabric.

[0143] Examples of thermoplastic resins include those exemplified in the other thermoplastic resins mentioned above. The thermoplastic resin may be used alone or in combination of two or more types. From the viewpoint of producing a prepreg with excellent heat resistance when solidified, it is preferable that the thermoplastic resin has a melting point at least 20°C lower than the lowest melting point of the nonwoven fabric.

[0144] The thickness of the prepreg can be appropriately selected depending on the intended use. From the viewpoint of improving the formability when laminating the prepreg, the mechanical strength and toughness of the cured product, etc., the thickness of the prepreg is preferably 0.001 mm to 10 mm, more preferably 0.005 mm to 1 mm, and even more preferably 0.01 mm to 0.5 mm.

[0145] The uses of the prepreg of this disclosure are not particularly limited, and it can be used, for example, in printed circuit boards as described later.

[0146] (4) Conductor Tensioned Laminate The conductive laminate of the present disclosure comprises a prepreg of the present disclosure and a conductive layer laminated on at least one surface of the prepreg. Because the conductive laminate of the present disclosure has the above configuration, it has excellent heat resistance.

[0147] The conductive layer is not particularly limited as long as it contains a conductive material, and metal foil is preferred. Examples of metal foils include copper foil, aluminum foil, nickel foil, gold foil, silver foil, and stainless steel foil. The conductive laminate of this disclosure can be manufactured by known manufacturing methods.

[0148] (5) Printed circuit board The printed circuit board of the present disclosure comprises a cured or solidified prepreg of the present disclosure, and a conductive layer disposed on one or both sides of the cured or solidified prepreg and subjected to wiring processing. Because the printed circuit board of the present disclosure has the above configuration, it has excellent heat resistance.

[0149] The printed circuit board may have a conductive layer on one or both sides of a laminate formed by stacking cured or solidified prepregs of the present disclosure, with wiring processing applied to each side.

[0150] The printed circuit board may have a conductive layer on one or both sides of the cured or solidified prepreg of the present disclosure, which is processed to form an antenna circuit.

[0151] The method for manufacturing a printed circuit board is not particularly limited, and known manufacturing methods can be applied. For example, in a method for manufacturing a printed circuit board, a prepreg manufactured by the aforementioned method is heat-cured by lamination press or the like to form an insulating layer. Next, a conductive layer is laminated onto the obtained insulating layer by a known method to create a laminate. After that, a printed circuit board can be obtained by processing the conductive layer in the laminate into a circuit or the like.

[0152] A metal is preferred for the conductive layer. Suitable metals include copper, aluminum, nickel, gold, silver, and stainless steel. Methods for forming the conductive layer include, for example, heat-sealing a conductive material such as metal into a foil to the insulating layer; bonding the insulating layer and the conductive layer using an adhesive; and forming the conductive layer by sputtering, vapor deposition, plating, etc. The printed circuit board may be single-sided or double-sided. The printed circuit board of this disclosure can be used as an electronic component by mounting electronic components such as semiconductor elements on it.

[0153] (6) Electronic components The electronic component of this disclosure is an electronic component having a circuit for transmitting electrical signals of 1 GHz or higher, and having an insulating layer containing a cured or solidified prepreg of this disclosure. The electronic component of this disclosure has excellent heat resistance due to the above configuration.

[0154] Electronic components can be manufactured using known methods. Examples of electronic components having circuits that transmit electrical signals of 1 GHz or higher include high-frequency antenna circuits, backplanes for high-speed servers and routers; flexible substrates for high-speed transmission used in hard disks, liquid crystal displays, etc.; and radar components.

[0155] (7) Method for manufacturing nonwoven fabrics The method for manufacturing the nonwoven fabric of the present disclosure is not particularly limited, but the spunbond method is preferred. Below, a method for manufacturing the nonwoven fabric of the present disclosure by the spunbond method when the nonwoven fabric is a blended nonwoven fabric will be described.

[0156] The method for manufacturing a nonwoven fabric according to this disclosure comprises a web-forming step and a division step. The web-forming step and the division step are carried out in this order. This results in a spunbond nonwoven fabric composed of multiple fibers having a smaller average fiber diameter than fibers produced by the conventional spunbond method.

[0157] (7.1) Web formation process In the web-forming process, a 4-methyl-1-pentene polymer (A) and an amorphous thermoplastic resin (B) are melted separately in an extruder, and the molten materials are discharged from a spinneret having a composite spinning nozzle to spin out multiple divided fibers. This yields a web composed of multiple divided fibers. Each divided fiber contains at least one solidified 4-methyl-1-pentene polymer (A) and at least one solidified amorphous thermoplastic resin (B).

[0158] The extruder is not particularly limited and may be a single-screw extruder or a multi-screw extruder. The resin fed from the hopper may be melted in the compression section of the extruder.

[0159] The spinneret is located at the tip of the extruder. The spinneret has a plurality of composite spinning nozzles. The spinneret with composite spinning nozzles has a structure such that, in the longitudinal cross-section of the divided fiber, each of the 4-methyl-1-pentene polymer (A) and amorphous thermoplastic resin (B) is arranged radially, parallel, or in a row. For example, the plurality of spinning nozzles may be arranged in a row.

[0160] Examples of spinnerets having composite spinning nozzles, spinnerets 10A to 10I, are shown in Figures 1(a) to 1(i). As shown in Figures 1(a) to 1(i), spinnerets 10A to 10I have a plurality of spinning nozzles 11 and a plurality of spinning nozzles 12. Molten 4-methyl-1-pentene polymer (A) is supplied to spinning nozzle 11, and molten amorphous thermoplastic resin (B) is supplied to spinning nozzle 12.

[0161] The diameter of the spinning nozzle is preferably 0.1 mm to 2.0 mm. The molten resin is transported by the extruder to the spinning die and introduced into the spinning nozzle. The molten resin in fibrous form is discharged from the opening of the spinning nozzle. The discharge pressure of the molten resin is 0.01 kgf / cm². 2 ~200 kgf / cm² 2 It is preferable that the discharge rate is within this range. By increasing the discharge rate, mass production of nonwoven fabrics can be achieved.

[0162] In this case, considering the decomposition of the 4-methyl-1-pentene polymer (A) and the amorphous thermoplastic resin (B), it is preferable that the melting temperature of these resins be in a temperature range of 20 to 100°C higher than the higher of the two temperatures: the melting point of the 4-methyl-1-pentene polymer (A) and the glass transition temperature of the amorphous thermoplastic resin (B).

[0163] The spun divided fibers are cooled with a cooling fluid such as air, and then tension is applied to the long fibers with a fluid such as stretching air to thin them to a predetermined fineness, and they are then deposited on a collection belt to a predetermined thickness. The cooling fluid and the fluid used to thin the divided fibers by applying tension may be the same or different.

[0164] The velocity (airflow rate) of the extending air is preferably 1000 Nm 3 / h / m~10000Nm 3 / h / m, more preferably 2000Nm 3 / h / m~6000Nm 3 The ratio is / h / m. This allows for the production of nonwoven fabrics with excellent texture. The temperature of the stretching air is usually between 5°C and 100°C, preferably in the range of 15°C to 50°C. In this process, it is necessary to appropriately select the molding temperature, spinning speed, and cooling air temperature within a range that provides good spinnability to orient the 4-methyl-1-pentene polymer (A) or to orient the amorphous thermoplastic resin (N). The orientation of the 4-methyl-1-pentene polymer (A) and the orientation of the amorphous thermoplastic resin are evaluated based on the difference in glass transition temperatures observed between the first and second heating cycles in DSC measurements.

[0165] (7.2) Segmentation process In the splitting process, stress is applied to the web made up of split fibers. This causes one split fiber to split into multiple fibers. Specifically, the solidified product of at least one 4-methyl-1-pentene polymer (A) contained in one split fiber becomes fiber (A). The solidified product of at least one amorphous thermoplastic resin (B) contained in one split fiber becomes fiber (B). In other words, a nonwoven fabric that is a blended fiber nonwoven is obtained.

[0166] The partitioning process may be performed immediately after the web formation process, or it may not be performed immediately after the web formation process. Other processes different from the web formation process and the partitioning process may be performed between the web formation process and the partitioning process.

[0167] The method of applying stress to the web is not particularly limited and includes methods such as high-pressure liquid flow. When applying high-pressure water flow to a web made of segmented fibers, it is preferable to replace the air present between adjacent segmented fibers constituting the web with water in order to promote entanglement, for example, before the step of applying segmented fiber splitting and entanglement by high-pressure liquid flow. Specifically, water can be applied to the web.

[0168] A high-pressure liquid flow is obtained by passing liquid through a nozzle hole, pressurizing it with a high-pressure pump, and then ejecting it. The diameter of the nozzle hole is typically 0.05 mm to 1.0 mm, preferably 0.1 mm to 0.5 mm. The pressure of the high-pressure liquid flow is typically 50 kgf / cm². 2 ~600 kgf / cm² 2 Preferably 50 kgf / cm² 2 ~250 kgf / cm² 2 The liquid is preferably water or warm water due to its ease of handling. The water or warm water is preferably pure water. The resistivity of the pure water, as measured by a known water quality measuring device, is preferably 10 MΩ·cm or higher, more preferably 15 MΩ·cm or higher.

[0169] The distance between the nozzle hole and the web is preferably between 0.5 cm and 15 cm. If this distance exceeds 15 cm, the energy imparted to the web by the liquid decreases, and the effect of splitting and entanglement of the split fibers tends to decrease. If the distance between the nozzle hole and the web is less than 0.5 cm, the web's structure tends to become disordered.

[0170] Generally, nozzle holes for high-pressure liquid flow are arranged in rows perpendicular to the direction of web propagation. When stress is applied to one side of the web, in order to obtain uniform splitting and tight entanglement of the split fibers, the rows in which multiple injection holes are arranged are preferably two or more, more preferably three or more. It is preferable to have a lower pressure for the high-pressure liquid flow on the upstream side and a higher pressure on the downstream side in order to achieve uniform formation. The number of times stress is applied to the web (hereinafter referred to as "number of processing times") is selected according to the method of applying stress to the web. When the method of applying stress to the web is a high-pressure liquid flow, the number of processing times is preferably 2 to 8 times, more preferably 3 to 7 times, and even more preferably 4 to 6 times.

[0171] The pattern of the nonwoven fabric can be changed by appropriately selecting the pattern of the screen belt used when processing high-pressure liquid flow.

[0172] Nonwoven fabrics that have undergone a splitting process using a high-pressure liquid flow are then subjected to mechanical squeezing to remove excess moisture, followed by drying and heat treatment to produce the final product. The heat treatment temperature and time can be selected not only to remove moisture but also to allow for moderate shrinkage and promotion of crystallization. The heat treatment may be dry heat treatment or wet heat treatment. [Examples]

[0173] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to the following examples unless it exceeds the spirit of the disclosure.

[0174] [1] Preparation [1.1] 4-methyl-1-pentene polymer (A) [1.1.1] 4-methyl-1-pentene polymer (A1) As the 4-methyl-1-pentene polymer (A) for Examples 1 to 3 and Comparative Example 2, the following 4-methyl-1-pentene polymer (A1) was prepared. 4-Methyl-1-pentene polymer (A1): 4-methyl-1-pentene / decene-1 copolymer (decene-1 content: 3% by mass, melting point (Tm): 233°C, melt flow rate (MFR): 320 g / 10 min, molecular weight distribution (Mw / Mn): 5, crystallization temperature (Tc): 214°C)

[0175] [1.1.2] 4-methyl-1-pentene polymer (A2) As the 4-methyl-1-pentene polymer (A) for Comparative Example 1, the following 4-methyl-1-pentene polymer (A2) was prepared. 4-Methyl-1-pentene polymer (A2): 4-methyl-1-pentene / decene-1 copolymer (decene-1 content: 3% by mass, melting point (Tm): 233°C, melt flow rate (MFR): 500g / 10min, molecular weight distribution (Mw / Mn): 3, crystallization temperature (Tc): 214°C)

[0176] [1.2] Cyclic olefin copolymer (B) As the cyclic olefin copolymer (B), cyclic olefin copolymer (B1) was prepared as follows.

[0177] [1.2.1] Preparation of catalyst A cyclohexane solution of a vanadium catalyst with a vanadium concentration of 6.7 mmol / L was prepared by diluting VO(OC2H5)Cl2 with cyclohexane. A cyclohexane solution of an organoaluminum compound catalyst with an aluminum concentration of 107 mmol / L was prepared by diluting ethylaluminum sesquichloride (Al(C2H5)1.5Cl1.5) with cyclohexane.

[0178] [1.2.2] Polymerization of monomers A continuous copolymerization reaction of ethylene and tetracyclo[4.4.0.12,5.17,10]-3-dodecene was carried out using a stirred polymerizer (inner diameter 500 mm, reaction volume 100 L). Here, ethylene was supplied into the polymerizer along with hydrogen gas. Cyclohexane was used as the polymerization solvent. During the polymerization reaction, a cyclohexane solution of the vanadium catalyst prepared by the above method was supplied into the polymerizer so that the vanadium catalyst concentration relative to the cyclohexane in the polymerizer was 0.6 mmol / L. Furthermore, ethylaluminum sesquichloride, an organoaluminum compound, was supplied to the polymerizer so that the mass ratio of aluminum to vanadium (Al / V) was 18.0. The polymerization temperature was set to 8°C and the polymerization pressure to 1.8 kg / cm². 2 The copolymerization reaction was carried out continuously as G to obtain a copolymer of ethylene and tetracyclo[4.4.0.12,5.17,10]-3-dodecene (ethylene-tetracyclo[4.4.0.12,5.17,10]-3-dodecene copolymer).

[0179] [1.2.3] Catalyst removal To a solution of ethylene-tetracyclo[4.4.0.12,5.17,10]-3-dodecene copolymer extracted from the polymerizer, a 25% by mass NaOH solution was added as water and a pH adjuster to stop the polymerization reaction. Catalyst residue present in the ethylene-tetracyclo[4.4.0.12,5.17,10]-3-dodecene copolymer was removed.

[0180] [1.2.4] Removal of unreacted monomers As a heat source: 20 kg / cm³ 2 A double-tube humidifier (outer tube diameter 2B, inner tube diameter 3 / 4B, length 21m) using water vapor G was supplied with a cyclohexane solution of the copolymer at a concentration of 5% by mass at a rate of 150 kg / h and heated to 180°C. A heat source of 25 kg / cm³ was used. 2 Using steam from G, and employing a double-tube flash dryer (outer tube diameter 2B, inner tube diameter 3 / 4B, length 27m) and a flash hopper (volume 200L), most of the unreacted monomers were removed from the cyclohexane solution of the copolymer that had undergone the above heating process, along with the polymerization solvent, cyclohexane. This yielded a flash-dried molten cyclic olefin polymer (B1).

[0181] [1.2.5] Extrusion of resin The molten cyclic olefin polymer (B1) described above was charged into a twin-screw compounding extruder with a vent from the resin charging section. Next, in order to remove volatile matter from the vent section, the extruder conditions were adjusted so that the difference between the maximum and minimum resin temperatures in the extruder diverter section was within 3°C, while suction was performed using a vacuum pump through a trap. Then, the material was pelletized using an underwater pelletizer attached to the extruder outlet, and the resulting pellets were dried with hot air at a temperature of 100°C for 4 hours. The glass transition temperature (Tg) of the cyclic olefin polymer (B1) constituting the pellets was measured using the method described later, and the Tg was found to be 135°C.

[0182] [2] Examples and Comparative Examples [2.1] Example 1 As the 4-methyl-1-pentene polymer (A), 4-methyl-1-pentene polymer (A1) is used, and as the amorphous thermoplastic resin, cyclic olefin polymer (B1) is used. The molding temperature of the 4-methyl-1-pentene polymer (A1) is 310 °C and the molding temperature of the cyclic olefin polymer (B1) is 300 °C, respectively, melted in separate extruders, and a split-type composite fiber spinning die with a cross-sectional shape as shown in Fig. 1(f) with a total number of segments of 16 is used. The speed (air volume) of the injected gas is 2240 Nm 3 / h / m, and the discharge amount per single hole is 0.6 g / min. Split fibers with a mass ratio of 50 / 50 of the 4-methyl-1-pentene polymer (A1) and the cyclic olefin polymer (B1) are spun. After the spun split fibers are stretched while being cooled by air (25 °C), they are deposited on a collecting belt to obtain a web. Next, in order to split the split fibers, a nozzle with a pore diameter of φ0.11 mm is used, the distance from the nozzle to the web is 1 cm, and a water jet process is applied 5 times to the surface of the web at a water pressure of 100 kgf / cm 2 , and a non-woven fabric with a basis weight of 31 g / m 2 is produced. When the obtained non-woven fabric was confirmed by an electron microscope, it was confirmed that a part of the split fibers was split into a plurality of fibers and the non-woven fabric was a conjugated fiber non-woven fabric. For the obtained non-woven fabric, various data were measured and evaluated. The results are shown in Table 1.

[0183] [2.2] Examples 2 and 3 A non-woven fabric was obtained in the same manner as in Example 1, except that the air volume of the gas was changed as shown in Table 1.

[0184] [2.3] Comparative Example 1 The 4-methyl-1-pentene polymer (A2) was spun by the melt blowing method under the conditions of a resin temperature of 345 °C and a speed (air volume) of the injected gas of 465 Nm 3 / h / m, and a non-woven fabric was obtained by collecting the fibers with a web former. The average fiber diameter of the obtained fibers was 2.5 μm. The basis weight of the obtained non-woven fabric was 30 g / m 2 .

[0185] [2.4] Comparative Example 2 A 4-methyl-1-pentene polymer (A1) was melted at a molding temperature of 310°C, and the gas was injected at a velocity (airflow) of 1600 Nm. 3 Long fibers of a 4-methyl-1-pentene polymer (A1) were spun at a discharge rate of 0.6 g / min per single pore at a rate of 0.6 g / min. The spun long fibers were then stretched while being cooled with air (25°C) and deposited on a collection belt. This yielded a nonwoven fabric. The average fiber diameter of the obtained fibers was 18 μm. The basis weight of the obtained nonwoven fabric was 30 g / m². 2 That was the case.

[0186] [3]Measurement method The measurement of the fiber properties of the nonwoven fabric is as follows. The measurement results for Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1.

[0187] [3.1] Glass transition temperature Fibers were collected from nonwoven fabric and used as samples. In accordance with JIS K7121 (1987), the extrapolation glass transition onset temperature of the samples was measured using differential scanning calorimetry (DSC) at a heating rate of 10°C / min. The measured extrapolation glass transition onset temperature was defined as the glass transition temperature (Tg).

[0188] [3.2] Glass transition temperature difference ΔTg Fibers were collected from nonwoven fabric and used as samples. Using DSC, the samples were melted by first heating at a heating rate of 10°C / min, then solidified by cooling at a cooling rate of 10°C / min, and then melted again by second heating at a heating rate of 10°C / min. At this time, the first glass transition temperature of the sample after first heating and the second glass transition temperature of the sample after second heating were measured in the same manner as the glass transition temperature measurement method described above (in accordance with JIS K7121 (1987)). The value obtained by subtracting the measured value of the second glass transition temperature from the measured value of the first glass transition temperature was defined as the glass transition temperature difference ΔTg. The samples in Examples 1 to 3 contained two different types of fibers.

[0189] [3.3] Average fiber diameter and coefficient of variation (CV value) Using an electron microscope (S-3500N manufactured by Hitachi, Ltd.), a photograph of the non-woven fabric at a magnification of 1000 times was taken. Fibers whose diameters could be measured were selected from the obtained photograph, and the diameters of the selected fibers were measured. Imaging and measurement were repeated until the total number of measured fibers exceeded 100. The arithmetic mean value of the measured values of the fiber diameters obtained was taken as the average fiber diameter. As shown in the following formula (1), the value obtained by dividing the standard deviation (Dp) of this measurement result by the average fiber diameter (Da) was taken as the coefficient of variation (CV value) of the fiber diameter. Formula (1): CV value = [standard deviation (Dp) / average fiber diameter (Da)] × 100

[0190] [3.4] Basis weight Three samples of 100 mm in the longitudinal direction and 100 mm in the transverse direction were taken from the non-woven fabric, and the mass of each sample was measured. The average value of the obtained measurement values was converted per unit area, and the value obtained by rounding off the first digit after the decimal point was taken as the basis weight (g / m 2 ).

[0191] [3.5] Thickness The thicknesses at five points, i.e., the center and the four corners of the main surface of the sample for which the basis weight was measured, were measured using a thickness gauge (manufactured by PEACOCK, product number "R1-250", measuring terminal 25 mmφ) at a load of 7 g / m 2 . For the three samples of the sample for which the basis weight was measured, the thickness was measured by this method, and the average value was taken as the thickness (mm).

[0192] [3.6] Specific surface area The specific surface area of the non-woven fabric is a value determined in accordance with JIS Z8830:2013.

[0193] [3.7] Average and standard deviation of absorbance Using Nomura Shoji Co., Ltd. Farmation Tester FMT-MIII, the average and standard deviation of the absorbance of the non-woven fabric were measured. The average value at five arbitrary locations was obtained and rounded off to the first digit after the decimal point.

[0194] [3.8] Collection efficiency The dust collection efficiency of nonwoven fabric was measured using the following method. Three 15cm x 15cm samples were taken from any part of the nonwoven fabric, and the collection efficiency of each sample was measured using a dust collection performance measuring device (Tokyo Direc Co., Ltd., Model 8130). For measuring the collection efficiency, NaCl particle dust with a number median diameter of 0.3 μm was generated using an atomizer, then the sample was set in a holder, and the airflow was adjusted using a flow control valve so that the filter passage velocity was 5.3 cm / sec, and the dust concentration was set to 15 mg / m³. 3 ~20mg / m 3 The sample size was stabilized within this range. The median number diameter represents the diameter corresponding to the 50% cumulative probability of the sample size distribution. The number of dust particles D2 upstream and D1 downstream of the sample were detected using a laser particle detector, and the collection efficiency was calculated by rounding the value obtained by the following formula (2) to the second decimal place. The arithmetic mean of the collection efficiencies of the three samples was taken as the collection efficiency. Equation (2): Collection efficiency = 1 - (D1 / D2) In equation (2), D1 represents the number of dust particles downstream, and D2 represents the number of dust particles upstream.

[0195] [3.9] Pressure loss The static pressure difference upstream and downstream of the sample during the measurement of the collection efficiency described above was read using a pressure gauge. The arithmetic mean of the measured static pressure differences of the three samples was defined as the pressure loss.

[0196] [3.10] Q value The Q value was calculated using equation (a) from the arithmetic mean of the measured pressure loss of the nonwoven fabric.

[0197] [3.11] Structural strength A sample measuring 50 mm wide x 200 mm long was taken from the nonwoven fabric. Using a tensile testing machine, the tensile strength (MD) in the fiber direction (MD) of the sample was measured at five points with a chuck distance of 100 mm and a head speed of 300 mm / min. The average of the five tensile strengths (MD) was defined as the structural strength (N / 50 mm). The acceptable range for structural strength is 8N / 50mm or more.

[0198] [3.12] Formation index The fabric consistency index was measured at five arbitrary points on the nonwoven fabric using a fabric consistency tester (FMT-MIII, Nomura Trading Co., Ltd.). The average of the five fabric consistency index measurements was rounded to the first decimal place and used as the fabric consistency index. The market sentiment index (V) is expressed by the following formula (2). Equation (2): V=10σ / E In equation (2), σ is the standard deviation of the density variation of the nonwoven fabric, and E is a value obtained from the light transmittance (T [%]) of the nonwoven fabric using the formula E = 2 - logT. When the light transmittance of the nonwoven fabric is close to 100% (poor fabrication), E ≈ 0, and V shows an infinitely large value. A smaller fabrication index indicates better fabrication.

[0199] [3.13] Molecular weight distribution of 4-methyl-1-pentene polymer (A) Using gel permeation chromatography (GPC) (Waters Alliance 2000 model), with Tosoh Corporation (GMH type) as the column and o-dichlorobenzene as the mobile phase, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in polystyrene equivalent were determined, and the molecular weight distribution (Mw / Mn) was calculated.

[0200] [3.14] Crystallization temperature and melting point of 4-methyl-1-pentene polymer (A) Using a differential scanning calorimeter (DSC) (PerkinElmer, PYRIS-I type), 5 mg of the sample was heated at 300°C for 5 minutes in an air atmosphere, then crystallized at a cooling rate of 20°C / min. The exothermic curve was determined, and the peak temperature was identified as the crystallization temperature (Tc). After cooling to room temperature, the sample was heated to 300°C at a heating rate of 20°C / min. The endothermic curve was determined, and the peak temperature was identified as the melting point (Tm).

[0201] [Table 1]

[0202] The notation in Table 1 is as follows: "SB" indicates the spunbond method. "MB" indicates the meltblown method. "(A)" indicates 4-methyl-1-pentene polymer (A). "(A1)" indicates 4-methyl-1-pentene polymer (A1). "(A2)" indicates 4-methyl-1-pentene polymer (A2). "(B)" indicates amorphous thermoplastic resin (B). "(B1)" indicates amorphous thermoplastic resin (B1). "(A)" in the "ΔTg" column indicates the glass transition temperature difference ΔTg of fiber (A) measured by differential scanning calorimeter (DSC). "(B)" in the "ΔTg" column indicates the glass transition temperature difference ΔTg of fiber (B) measured by differential scanning calorimeter (DSC).

[0203] In Comparative Example 1, the glass transition temperature difference ΔTg of the 4-methyl-1-pentene polymer (A) was not 4.0°C or greater. Therefore, the structural strength of the nonwoven fabric in Comparative Example 1 was less than 8 N / 50 mm. In Comparative Example 2, the average fiber diameter was not 10 μm or less. In other words, the fibers in Comparative Example 2 were not thin. These results show that the nonwoven fabrics of Comparative Example 1 and Comparative Example 2 are not nonwoven fabrics that have excellent mechanical strength and heat resistance, even if the fibers are fine.

[0204] In Examples 1 to 3, the nonwoven fabrics contained fibers with a 4-methyl-1-pentene polymer (A). The glass transition temperature difference ΔTg of the 4-methyl-1-pentene polymer (A) was 4.0°C or higher. The average fiber diameter was 10 μm or less. Therefore, the structural strength of the nonwoven fabrics in Examples 1 to 3 was 8 N / 50 mm or higher. These results show that the nonwoven fabrics of Examples 1 to 3 are excellent in heat resistance and structural strength even with fine fibers.

Claims

1. A nonwoven fabric which is a blended nonwoven fabric, The nonwoven fabric comprises fibers (A) containing a 4-methyl-1-pentene polymer (A) and fibers (B) containing an amorphous thermoplastic resin (B). The glass transition temperature difference ΔTg of the fiber (A), as measured by a differential scanning calorimeter (DSC), is 4.0°C or higher. The glass transition temperature difference ΔTg of the fiber (B), as measured by a differential scanning calorimeter (DSC), is 0.8°C or higher. The ratio of resin composition A constituting the fiber (A) to resin composition B constituting the fiber (B) (resin composition A: resin composition B) is 70:30 to 30:

70. The average fiber diameter of the aforementioned fibers is 10 μm or less. The basis weight of the aforementioned nonwoven fabric is 5 g / m² to 100 g / m². A nonwoven fabric having a structural strength of 10 N / 50 mm or more.

2. The specific surface area is 1.3 m². ２ The nonwoven fabric according to claim 1, wherein the weight is 1 / g or more.

3. The aforementioned 4-methyl-1-pentene polymer (A) 90 to 100 mol% of constituent units derived from 4-methyl-1-pentene, 0 to 10 mol% of constituent units derived from olefins with 2 to 20 carbon atoms other than 4-methyl-1-pentene, A nonwoven fabric according to claim 1 or claim 2, comprising:

4. The amorphous thermoplastic resin (B) comprises a cyclic olefin polymer (B-1), The cyclic olefin polymer (B-1) comprises at least one selected from a cyclic olefin copolymer (B-1-1) and a ring-opening polymer of a cyclic olefin (B-1-2). The nonwoven fabric according to claim 1 or claim 2, wherein the cyclic olefin copolymer (B-1-1) comprises the following structural unit (a) and the following structural unit (b). Structural unit (a): A structural unit derived from an olefin compound, which is at least one of the following general formulas (I). Structural unit (b): A structural unit derived from a cyclic olefin compound, which is at least one selected from the group consisting of the structural unit represented by the following general formula (II), the structural unit represented by the following general formula (III), and the structural unit represented by the following general formula (IV). 【Chemistry 1】 In the above general formula (I), R ３００ This is a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 29 carbon atoms. 【Chemistry 2】 In the general formula (II) above, u is 0 or 1, v is 0 or a positive integer, and w is 0 or 1. ６１ ~R ７８ And R ａ１ and R ｂ１ These may be the same or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkyl halide having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. ７５ ~R ７８ At least two of these may be bonded to each other to form a monocycle or polycycle. 【Transformation 3】 In the general formula (III), x and d are each independently an integer of 0 or 1 or more. y and z are each independently an integer of 0 to 2. R ８１ ~R ９９ may be the same as or different from each other, and is a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an alkoxy group. R ８９ and R ９０ The carbon atom to which is bonded, the carbon atom to which R ９３ is bonded or the carbon atom to which R ９１ is bonded may be bonded directly or via an alkylene group having 1 to 3 carbon atoms. When y = z = 0, R ９２ and R ９５ or R ９５ and R ９９ and R may be bonded to each other to form a monocyclic or polycyclic aromatic ring. 【Chemistry 4】 In the above general formula (IV), R １００ and R １０１ These elements may be the same or different from each other, and are hydrogen atoms or hydrocarbon groups having 1 to 5 carbon atoms. f is 1 ≤ f ≤ 18.

5. The nonwoven fabric according to claim 4, wherein the cyclic olefin polymer (B-1) comprises the cyclic olefin copolymer (B-1-1).

6. The nonwoven fabric according to claim 5, wherein the cyclic olefin copolymer (B-1-1) comprises the structural unit (a) and the following structural unit (c). Structural unit (c): A structural unit represented by the general formula (II) above, where u is 0 and v is 1.

7. The nonwoven fabric according to claim 1 or claim 2, wherein the glass transition temperature Tg of the fiber (B), as measured by differential scanning calorimeter (DSC), is 85°C or higher.

8. A filter comprising the nonwoven fabric described in claim 1 or claim 2.

9. The filter according to claim 8, wherein the filter is a bug filter.

10. A nonwoven fabric according to claim 1 or claim 2, A resin composition comprising at least one of a thermosetting resin and a thermoplastic resin, Prepreg, including

11. The thermosetting resin is a thermosetting resin having a curing temperature that is 20°C or more lower than the lowest melting point of the nonwoven fabric. The prepreg according to claim 10, wherein the thermoplastic resin has a melting point at least 20°C lower than the lowest melting point of the nonwoven fabric.

12. A cured or solidified product of the prepreg according to Claim 10, A conductive layer, which is arranged on one or both sides of the cured or solidified product and has been subjected to wiring processing, A printed circuit board having the following features.

13. An electronic component having a circuit for transmitting electrical signals of 1 GHz or higher, An electronic component having an insulating layer containing a cured or solidified prepreg according to claim 10.

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